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  Subjects -> ELECTRONICS (Total: 207 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
ACS Applied Electronic Materials     Open Access   (Followers: 1)
Acta Electronica Malaysia     Open Access  
Advanced Materials Technologies     Hybrid Journal   (Followers: 2)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 5)
Advances in Electronics     Open Access   (Followers: 122)
Advances in Microelectronic Engineering     Open Access   (Followers: 12)
Advances in Power Electronics     Open Access   (Followers: 56)
Advancing Microelectronics     Hybrid Journal   (Followers: 2)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 26)
Annals of Telecommunications     Hybrid Journal   (Followers: 6)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 8)
Archives of Electrical Engineering     Open Access   (Followers: 14)
Australian Journal of Electrical and Electronics Engineering     Hybrid Journal  
Automatika : Journal for Control, Measurement, Electronics, Computing and Communications     Open Access  
Batteries     Open Access   (Followers: 8)
Batteries & Supercaps     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
Bioelectronics in Medicine     Hybrid Journal  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 50)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Electronics     Open Access  
Circuits and Systems     Open Access   (Followers: 16)
Control Systems     Hybrid Journal   (Followers: 235)
e-Prime : Advances in Electrical Engineering, Electronics and Energy     Open Access   (Followers: 2)
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access   (Followers: 1)
Edu Elektrika Journal     Open Access   (Followers: 1)
Electronic Design     Partially Free   (Followers: 125)
Electronic Markets     Hybrid Journal   (Followers: 6)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 125)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 8)
Electronics For You     Partially Free   (Followers: 114)
Electronics Letters     Open Access   (Followers: 25)
Elektronika ir Elektortechnika     Open Access  
Elkha : Jurnal Teknik Elektro     Open Access  
Emitor : Jurnal Teknik Elektro     Open Access  
Energy Storage     Hybrid Journal   (Followers: 2)
Energy Storage Materials     Full-text available via subscription   (Followers: 5)
EPE Journal : European Power Electronics and Drives     Hybrid Journal   (Followers: 3)
EPJ Quantum Technology     Open Access   (Followers: 2)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 7)
Frontiers in Electronics     Open Access   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 112)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 88)
IEEE Embedded Systems Letters     Hybrid Journal   (Followers: 60)
IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology     Hybrid Journal  
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 52)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 8)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 2)
IEEE Letters on Electromagnetic Compatibility Practice and Applications     Hybrid Journal   (Followers: 1)
IEEE Magnetics Letters     Hybrid Journal   (Followers: 7)
IEEE Nanotechnology Magazine     Hybrid Journal   (Followers: 45)
IEEE Open Journal of Circuits and Systems     Open Access  
IEEE Open Journal of Industry Applications     Open Access  
IEEE Open Journal of the Industrial Electronics Society     Open Access  
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 90)
IEEE Pulse     Hybrid Journal   (Followers: 5)
IEEE Reviews in Biomedical Engineering     Hybrid Journal   (Followers: 19)
IEEE Solid-State Circuits Letters     Hybrid Journal  
IEEE Solid-State Circuits Magazine     Hybrid Journal   (Followers: 11)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 281)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 79)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 65)
IEEE Transactions on Autonomous Mental Development     Hybrid Journal   (Followers: 8)
IEEE Transactions on Biomedical Engineering     Hybrid Journal   (Followers: 35)
IEEE Transactions on Broadcasting     Hybrid Journal   (Followers: 11)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 31)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 45)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 18)
IEEE Transactions on Geoscience and Remote Sensing     Hybrid Journal   (Followers: 174)
IEEE Transactions on Haptics     Hybrid Journal   (Followers: 4)
IEEE Transactions on Industrial Electronics     Hybrid Journal   (Followers: 85)
IEEE Transactions on Industry Applications     Hybrid Journal   (Followers: 57)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 27)
IEEE Transactions on Learning Technologies     Full-text available via subscription   (Followers: 12)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 87)
IEEE Transactions on Services Computing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Signal and Information Processing over Networks     Hybrid Journal   (Followers: 14)
IEEE Transactions on Software Engineering     Hybrid Journal   (Followers: 84)
IEEE Women in Engineering Magazine     Hybrid Journal   (Followers: 11)
IEEE/OSA Journal of Optical Communications and Networking     Hybrid Journal   (Followers: 19)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 11)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
IET Energy Systems Integration     Open Access   (Followers: 1)
IET Microwaves, Antennas & Propagation     Open Access   (Followers: 35)
IET Nanodielectrics     Open Access  
IET Power Electronics     Open Access   (Followers: 76)
IET Smart Grid     Open Access   (Followers: 2)
IET Wireless Sensor Systems     Open Access   (Followers: 17)
IETE Journal of Education     Open Access   (Followers: 3)
IETE Journal of Research     Open Access   (Followers: 10)
IETE Technical Review     Open Access   (Followers: 9)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Informatik-Spektrum     Hybrid Journal   (Followers: 3)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 12)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 10)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 14)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 12)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 23)
International Journal of Antennas and Propagation     Open Access   (Followers: 10)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 3)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 5)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 8)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Hybrid Intelligence     Hybrid Journal   (Followers: 1)
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 22)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 16)
International Journal of Nanoscience     Hybrid Journal  
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
International Journal of Power Electronics     Hybrid Journal   (Followers: 30)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 2)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 13)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 6)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 12)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 4)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 18)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 41)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 4)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 6)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 10)
Journal of Electronic Science and Technology     Open Access  
Journal of Electronics (China)     Hybrid Journal   (Followers: 5)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Engineered Fibers and Fabrics     Open Access  
Journal of Field Robotics     Hybrid Journal   (Followers: 5)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 165)
Journal of Information and Telecommunication     Open Access   (Followers: 2)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 2)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 14)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 9)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal   (Followers: 2)
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal   (Followers: 8)
Journal of Nuclear Cardiology     Hybrid Journal   (Followers: 1)
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Journal of Power Electronics     Hybrid Journal   (Followers: 8)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 19)
Journal of Sensors     Open Access   (Followers: 25)
Jurnal Rekayasa Elektrika     Open Access  
Jurnal Teknik Elektro     Open Access  
Jurnal Teknologi Elektro     Open Access  
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access   (Followers: 5)
Machine Learning with Applications     Full-text available via subscription   (Followers: 3)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 1)
Metrology and Measurement Systems     Open Access   (Followers: 8)
Microelectronics and Solid State Electronics     Open Access   (Followers: 27)
Nanotechnology, Science and Applications     Open Access   (Followers: 7)
Nature Electronics     Hybrid Journal   (Followers: 3)
Networks: an International Journal     Hybrid Journal   (Followers: 4)
npj Flexible Electronics     Open Access  
Open Electrical & Electronic Engineering Journal     Open Access   (Followers: 1)
Open Journal of Antennas and Propagation     Open Access   (Followers: 8)
Power Electronics and Drives     Open Access   (Followers: 2)
Problemy Peredachi Informatsii     Full-text available via subscription  
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 8)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 6)
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 62)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Sensors International     Open Access   (Followers: 3)
Solid State Electronics Letters     Open Access  
Solid-State Electronics     Hybrid Journal   (Followers: 7)
Superconductivity     Full-text available via subscription   (Followers: 4)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 4)
Technical Report Electronics and Computer Engineering     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 2)
Transactions on Cryptographic Hardware and Embedded Systems     Open Access   (Followers: 1)
Transactions on Electrical and Electronic Materials     Hybrid Journal   (Followers: 2)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
Ural Radio Engineering Journal     Open Access   (Followers: 1)
Visión Electrónica : algo más que un estado sólido     Open Access  
Wireless and Mobile Technologies     Open Access   (Followers: 4)
Електротехніка і Електромеханіка     Open Access   (Followers: 1)

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IEEE Transactions on Aerospace and Electronic Systems
Journal Prestige (SJR): 0.611
Citation Impact (citeScore): 3
Number of Followers: 281  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0018-9251
Published by IEEE Homepage  [228 journals]
  • IEEE Aerospace and Electronic Systems Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Dual Quaternion Kalman Filtering and Observability Analysis for Satellite
           Relative Navigation With Line-of-Sight Measurements

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      Authors: Yigal Zivan;Daniel Choukroun;
      Pages: 754 - 765
      Abstract: This article is concerned with the development of two novel Kalman filters for satellite relative pose estimation. The relative pose, which is represented by a dual quaternion, is estimated from noisy lines-of-sight via a single camera, along with biases of linear velocity and angular rate measurements. The constraints on the dual quaternion are handled by brute-force and virtual measurement techniques. The partial reset analysis shows how to propagate the estimation error biases and covariances. Closed-form expressions for the Jacobians are provided. A quantitative observability analysis for the position states is provided. Compared with traditional representations, the dual quaternion model increases the position observability by a factor of four for each line-of-sight. The additive dual quaternion model enhances the observability of the rotation states thanks to a specific coupling term in the pose dynamics. Extensive Monte-Carlo simulations of a flight formation case verify that the proposed novel filters are asymptotically unbiased and statistically consistent for all practical purposes. They outperform the other candidate estimators in particular during the transient phase. The numerical simulations validate the observability analysis.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Kalman Filter and Correlated Measurement Noise: The Variance Inflation
           Factor

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      Authors: Gaël Kermarrec;Ankit Jain;Steffen Schön;
      Pages: 766 - 780
      Abstract: Observations from high rate sensors are known to be time-correlated. When processed in a Kalman filter (KF) without accounting for correlations, i) a discrepancy with the true solution occurs, up to a divergence of the filter and ii) the covariance estimates are overestimated, which is equally problematic. Two main solutions exist to account for correlations in a KF: The time differenced and the state augmentation approach. They both model the correlated noise corresponding to an autoregressive process of the first order (AR(1), also called the Gauss Markov process) as it has a short memory, is linear and can be easily implemented. In this contribution, we propose a new method to account for measurement correlations by means of a variance inflation factor (VIF). The latter is derived from an AR(1) assumption for the measurement noise, and its parameters can be estimated by whitening the KF residuals. Our proposal, called the KF_VIF, is further extended to an AR(p) model to account for finer correlation structures. We compare the different approaches and address the impact of noise mismodeling. We use simulations to test the sensitivity of the KF solution to misspecifications and show that the KF_VIF proposed is a powerful answer to account for correlated measurement noise. A real case analysis corresponding to a precomputed flight trajectory with a constant velocity validates the results of the simulations.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Performance of UAV-Assisted Multiuser Terrestrial-Satellite Communication
           System Over Mixed FSO/RF Channels

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      Authors: Praveen Kumar Singya;Mohamed-Slim Alouini;
      Pages: 781 - 796
      Abstract: In this letter, performance of a multiantenna multiuser unmanned aerial vehicle (UAV)-assisted terrestrial-satellite communication system over mixed free space optics (FSO)/radiofrequency (RF) channels is analyzed. Downlink transmission from the satellite to the UAV is completed through FSO link which follows gamma–gamma distribution with pointing error impairments. Both the heterodyne detection and intensity modulation direct detection techniques are considered at the FSO receiver. To avail the antenna diversity, multiple transmit antennas are considered at the UAV. Selective decode-and-forward scheme is assumed at the UAV and opportunistic user scheduling is performed while considering the practical constraints of outdated channel state information (CSI) during the user selection and transmission phase. The RF links are assumed to follow Nakagami-m distribution due to its versatile nature. In this context, for the performance analysis, analytical expressions of outage probability, asymptotic outage probability, ergodic capacity, effective capacity, and generalized average symbol-error-rate expressions of various quadrature amplitude modulation (QAM) schemes such as hexagonal-QAM, cross-QAM, and rectangular QAM are derived. A comparison of various modulation schemes is presented. Further, the impact of pointing error, number of antennas, delay constraint, fading severity, and imperfect CSI are highlighted on the system performance. Finally, all the analytical results are verified through the Monte–Carlo simulations.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Adaptive Confidence Verification for Analysis of BPSK Signals

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      Authors: Guobing Hu;Bin Gu;Mengxi Xu;Weiping Wang;Pinjiao Zhao;
      Pages: 797 - 814
      Abstract: The existing extreme statistic-based confidence test approaches for the analysis results of binary phase-shift keying (BPSK) signals, i.e., modulation recognition and parameter estimation, do not perform well under transmission impairments, partly due to their insufficient use of extreme samples. This article proposes a copula-based algorithm for the confidence test of BPSK signal analysis by combining the block maxima-based and peak-over-the-threshold-based extreme statistics. The test statistic is developed relying on the one-class detector using the copula probability density function under the null hypothesis, and the threshold is obtained adaptively through the bootstrap algorithm. The proposed statistic is proved to be asymptotically Gaussian distributed. By comparing the statistic with such a threshold, the confidence test is performed. Extensive simulations validate the effectiveness of the proposed algorithm.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • 3-D Target Localization and Motion Analysis Based on Doppler Shifted
           Frequencies

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      Authors: Musaab M. Ahmed;K. C. Ho;Gang Wang;
      Pages: 815 - 833
      Abstract: This article proposes two algorithms for the localization or motion analysis of a moving target, by using a number of stationed sensors observing the frequency of the emitted target signal. This is a challenging problem due to the complicated non-linear relation between the target location parameters and the observations. The first algorithm is closed-form through algebraic evaluation that is computationally efficient. The second is derived from semidefinite programming by relaxationthat is robust against noise. The situations of having target frequency known but erroneous and completely unknown are investigated, as well as the presence of sensor position errors. Sequential algorithms for motion analysis are proposed in addition to the two for reducing latency and complexity. The algorithms are analyzed and their performance is able to achieve the CRLB accuracy under Gaussian noise.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Range–Angle Transceiver Beamforming Based on Semicircular-FDA
           Scheme

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      Authors: Yanhong Xu;Anyi Wang;Jingwei Xu;
      Pages: 834 - 843
      Abstract: Incontrast to the steady angle-dependent transmit beampattern of the conventional phased array, the counterpart of a frequency diverse array (FDA) is basically time variant and range–angle coupled, which limits its potential application in many scenarios. In this article, we consider the beamforming in joint transmit and receive domains to handle the time-variant problem and propose a novel range–angle transceiver beamforming approach based on the semicircular-FDA scheme. In particular, the transceiver scheme of semicircular-FDA is first established.In the sequel, the periodicities of its transceiver beampattern in range and angle dimensions are briefly analyzed. Based on this analysis, a semicircular-FDA applied with nonlinearly increasing frequency offset (NIFO), termed as NIFO semicircular-FDA, is proposed to achieve the beampattern with a single mainlobe peak in range–angle space. Then, an optimization problem is constructed based on an advanced bat algorithm to further reduce the sidelobe level (SLL) of the NIFO semicircular-FDA. Numerical results show that focused time-invariant beampattern with low SLL in both range and angle dimensions can be achieved with the proposed approach.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Optimal Sensor Precision for Multirate Sensing for Bounded Estimation
           Error

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      Authors: Niladri Das;Raktim Bhattacharya;
      Pages: 844 - 854
      Abstract: We address the problem of determining optimal sensor precisions for estimating the states of linear time-varying discrete-time stochastic dynamical systems, with guaranteed bounds on the estimation errors. This is performed in the Kalman filtering framework, where the sensor precisions are treated as variables. They are determined by solving a constrained convex optimization problem, which guarantees the specified upper bound on the posterior error variance. Optimal sensor precisions are determined by minimizing the $l_1$ norm, which promotes sparseness in the solution and indirectly addresses the sensor selection problem. The theory is applied to realistic flight mechanics and astrodynamics problems to highlight its engineering value. These examples demonstrate the application of the presented theory to 1) determine redundant sensing architectures for linear time invariant systems, 2) accurately estimate states with low-cost sensors, and 3) optimally schedule sensors for linear time-varying systems.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Range-Dependent Ambiguous Clutter Suppression for Airborne SSF-STAP Radar

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      Authors: Wei Chen;Wenchong Xie;Yongliang Wang;
      Pages: 855 - 867
      Abstract: Range-dependent clutter suppression is a challenging problem in nonsidelooking, bistatic, and conformal antenna array airborne radar, especially in the presence of range ambiguity. Superimposed stepped frequency (SSF) radar employs a small frequency increment across the stepped signals in each pulse, which introduces a dimension related to slant range. In this article, an airborne radar framework is established, which takes SSF signal as the transmit waveform. Thus, a two-stage adaptive clutter suppression method is proposed, which utilizes the degrees of freedom in range, space, and time domains provided by airborne SSF radar. In the first stage, the secondary range dependence compensation approach is adopted to distinguish the clutter of each range region in the carrier frequency domain. Then, a target-free covariance matrix is estimated by the compensated data, and the covariance matrix is used for the range-ambiguous clutter separation in the carrier frequency domain. Thus, the space-time snapshot of each range region can be extracted. In the second stage, a clutter segmentation processing method is devised for residual clutter suppression. For the near-range unambiguous clutter, the traditional clutter compensation approach is applied to further align the spectrum distribution of clutter, while the conventional space-time adaptive processing is utilized to suppress far-range clutter directly. Since the proposed method takes full advantage of the range dimension and the two stages of adaptive processing are data-dependent, excellent clutter suppression performance can be obtained. The proposed method can also extract the real range of the target since each range region is processed separately. Simulation results demonstrate the effectiveness of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Radio Frequency Interference Detection Using Nonnegative Matrix
           Factorization

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      Authors: Felipe B. da Silva;Ediz Cetin;Wallace A. Martins;
      Pages: 868 - 878
      Abstract: This article proposes a new precorrelation interference detection technique based on the nonnegative matrix factorization (NMF) for global navigation satellite system (GNSS) signals. The proposed technique uses the NMF to extract the time and frequency properties of the received signal from its spectrogram. The estimated spectral shape is then compared with the spectrogram’s time slices by means of a similarity function to detect the presence of radio frequency interference (RFI). In the presence of RFI, the NMF estimated spectral shape tends to be well-defined, resulting in high similarity levels. In contrast, in the absence of RFI, the received signal is solely comprised of noise and GNSS signals resulting in a noise like spectral shape estimate, leading to considerably reduced similarity levels. The proposal exploits these different similarity levels to detect the presence of interference. Simulation results indicate that the proposed technique yields increased detection capability with low false alarm rate even in low jammer-to-noise ratio environments for both narrow and wideband interference sources without requiring fine tuning of parameters for specific RFI types. In addition, the proposal has reduced computational complexity, when compared with an existing statistical-based detector.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • RFI Mitigation for One-Bit UWB Radar Systems

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      Authors: Tianyi Zhang;Jiaying Ren;Jian Li;Lam H. Nguyen;Petre Stoica;
      Pages: 879 - 889
      Abstract: Radio frequency interference (RFI) mitigation is critical to the proper operation of ultrawideband (UWB) radar systems because RFI can severely degrade the radar imaging capability and target detection performance. In this article, we address the RFI mitigation problem for one-bit UWB radar systems. A one-bit UWB system obtains its signed measurements via a low-cost and high rate sampling scheme, referred to as the continuous time binary value (CTBV) technology. This sampling strategy compares the signal to a known threshold that varies with slow-time and can be used to achieve a high sampling rate and quantization resolution with simple and affordable hardware. This article establishes a proper data model for the RFI sources and proposes a novel RFI mitigation method for the one-bit UWB radar system that uses the CTBV sampling technique. Specifically, we model the RFI sources as a sum of sinusoids with frequencies fixed during the coherent processing interval (CPI) and we exploit the sparsity of the RFI spectrum. We use an extended majorization-minimization-based 1bRELAX algorithm, referred to as 1bMMRELAX, to estimate the RFI source parameters from the signed measurements obtained by using the CTBV sampling strategy. We also devise a new fast frequency initialization method for the extended 1bMMRELAX algorithm to improve its computational efficiency. Moreover, a sparse method is introduced to recover the desired radar echoes using the estimated RFI parameters. Both simulated and experimental results are presented to demonstrate that our proposed algorithm outperforms the existing digital integration method, especially for severe RFI cases.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Poisson Multi-Bernoulli Approximations for Multiple Extended Object
           Filtering

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      Authors: Yuxuan Xia;Karl Granström;Lennart Svensson;Maryam Fatemi;Ángel F. García-Fernández;Jason L. Williams;
      Pages: 890 - 906
      Abstract: The Poisson multi-Bernoulli mixture (PMBM) is a multiobject conjugate prior for the closed-form Bayes random finite set filter. The extended object PMBM filter provides a closed-form solution for multiple extended object filtering with standard models. This article considers computationally lighter alternatives to the extended object PMBM filter by propagating a Poisson multi-Bernoulli (PMB) density through the filtering recursion. A new local hypothesis representation is presented, where each measurement creates a new Bernoulli component. This facilitates the developments of methods for efficiently approximating the PMBM posterior density after the update step as a PMB. Based on the new hypothesis representation, two approximation methods are presented: one is based on the track-oriented multi-Bernoulli (MB) approximation, and the other is based on the variational MB approximation via Kullback–Leibler divergence minimization. The performance of the proposed PMB filters with gamma Gaussian inverse-Wishart implementations are evaluated in a simulation study.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Cooperative Range and Angle Estimation With PA and FDA Radars

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      Authors: Jingjing Zhu;Shengqi Zhu;Jingwei Xu;Lan Lan;Xiongpeng He;
      Pages: 907 - 921
      Abstract: Target localization with unambiguous range and angle estimation of the signal-of-interest is a key task of a radar system, especially for wide region surveillance. In this article, we develop a novel dual-mode array radar scheme, namely phased array and frequency diverse array cooperated radar, to provide unambiguous range and angle estimation. Our approach combines the advantages of the PA in high transmit gain and that of the FDA in resolving range ambiguity. In general, two kinds of cooperative parameter estimation algorithms are derived to determine the range and angle parameters jointly. The proposed algorithms can be interpreted as different combination methods of the PA and FDA, including the uniform combination and weighted combination based on weighted least squares, where the weight is designed with user tunable angle parameters. Particularly, the design criterion for the tunable parameter is given. At the analysis stage, the Cramér–Rao bounds are studied to verify the performance of parameter estimation. Extensive simulation results demonstrate the effectiveness of parameter estimation with the dual-mode array radar.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Relative Orbital Motion of a Charged Object Near a Spaceborne Radially
           Directed Rotating Magnetic Dipole

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      Authors: Chao Peng;Zhengfan Zhu;Hao Zhang;Changxuan Wen;
      Pages: 922 - 941
      Abstract: The relative orbital motion of a charged object near a spaceborne magnetic dipole is presented in this article, where the intersatellite Lorentz force is taken into consideration. Assuming that a reference point is constrained in a circular reference orbit, a chief satellite and a constantly charged object move close to the reference point. Under the assumptions that the chief satellite generates a rotating magnetic dipole (the axis of the dipole is in the direction of the reference orbital radius vector) and the charged object moves nearby in the artificial magnetic field, a nonlinear dynamical model of the proposed relative motion is established based on the Hill–Clohessy–Wiltshire equation. We first derive the system’s equilibrium points and analyze their stabilities based on the system parameters, such as the charge-to-mass ratio of the charged object, the moment and rotating rate of the magnetic dipole, and the angular velocity of the reference orbit. All of the equilibrium points are classified into ten cases, and their structures of the submanifold (which determine the stable and unstable behaviors near the equilibrium points) are described according to their stability characteristics. In addition, the necessary and sufficient conditions for the ten cases are derived, and the periodic orbits near the equilibrium points are depicted in detail. Subsequently, an integral constant and zero-velocity surfaces in the dynamical system are derived to present the bounded orbits around the magnetic dipole and the transient orbits that travel through the equilibrium points. The flight mechanics of the presented relative orbital motion, including equilibrium points, periodic orbits, bounded orbits, and transient orbits, reveals the prospects of potential applications for proximity operations to a wide range of charged space objects.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Modeling of Fixed Service Interference in Aeronautical SATCOM Channels

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      Authors: Stephan P. Winter;Andreas Knopp;
      Pages: 942 - 961
      Abstract: A detailed assessment of the radiofrequency interference from terrestrial fixed service into aeronautical earth stations operating with geostationary satellite orbit networks in the fixed-satellite service is performed. We analyze the impact of the major physical, technical, operational, and regulatory parameters in the interference environment having multiple degrees of freedom to be considered. By performing exhaustive geometric computer simulations, we determine the statistical characteristics of the time-variant radiofrequency interference caused by multiple terrestrial fixed service transmitters using information of existing/registered fixed service stations in France. Subsequently, a stochastic channel model to predict the impact of the terrestrial interference using a higher order finite-state Markov process is developed. Balancing model accuracy and complexity, a reasonable vector quantization clustering algorithm is applied for the partitioning of the interference into representative channel states. For these channel states, we provide a method for scaling this model to different antenna sizes and flight velocities, to be used for development of interference mitigation measures and system design of aeronautical earth stations in motion operating in the 17.7–19.7 GHz frequency range.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Entropy-Driven Morphological Top-Hat Transformation for Infrared Small
           Target Detection

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      Authors: Lizhen Deng;Guoxia Xu;Jieke Zhang;Hu Zhu;
      Pages: 962 - 975
      Abstract: Infrared small target detection is a key technique in an infrared system. In the past decade, many methods have concentrated on traditional top-hat transformation, which relies on the hand-crafted shape and value of structural elements. However, these methods are inevitably challenged by the following two aspects: first, the structural elements cannot suppress heavy clutter because the construction of structural elements is always according to the prior information of the target and unable to consider the feature of clutter. Second, adaptively extracting sufficient local feature information for background suppression is hard for the structural element. In this article, we propose an entropy-driven top-hat transformation with guided filter kernel for considering the features of both the clutters and background. First, we propose an entropy-driven top-hat transformation method with our proposed local mean entropy, which can be used to suppress clutter according to the local complex degree of clutter. Then, an adaptive structural element based on a guided filter kernel is further exploited to capture the local feature information of image for background suppression. Finally, an adaptive threshold is combined with our algorithm to achieve target detection in image sequences. The experimental results show that the proposed algorithm is not only robust for suppressing different kinds of backgrounds but can also obtain a higher value of the signal-to-clutter ratio gain and detection accuracy compared with some popular traditional baseline methods and related top-hat methods.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Bayesian Approximation Filtering With False Data Attack on Network

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      Authors: Abhinoy Kumar Singh;Sumit Kumar;Nagendra Kumar;Rahul Radhakrishnan;
      Pages: 976 - 988
      Abstract: Very often, a measurement is transmitted through network systems before it is available for filtering. The network systems, designed with several communication channels, are prone to cyber-attacks. The cyber-attack often injects false data to alter the original measurement. This article develops a modified Bayesian approximation filtering method for nonlinear filtering with measurements altered due to cyber-attack. The proposed development is within the scope of nonlinear Gaussian filtering. It considers the false data to have either additive or multiplicative effect over the original measurement. Subsequently, two modified measurement models are introduced to model the possibility of false data stochastically. Then, the traditional nonlinear Gaussian filtering method is redesigned for the modified measurement models to deal with the false data attack. The proposed modification is applicable to any of the existing nonlinear Gaussian filters, such as extended Kalman filter, unscented Kalman filter, cubature Kalman filter, and Gauss–Hermite filter. The simulation results show an enhanced estimation accuracy for the proposed modification over the traditional nonlinear Gaussian filtering in the presence of false data.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • An Autofocus Approach With Applications to Ionospheric Scintillation
           Compensation for Spaceborne SAR Images

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      Authors: Yifei Ji;Zhen Dong;Yongsheng Zhang;Qilei Zhang;
      Pages: 989 - 1004
      Abstract: Spaceborne synthetic aperture radar (SAR) systems, operating at L-band or lower, are very susceptible to ionospheric scintillation. The scintillation phase error (SPE) can bring about serious azimuth decorrelation and resolution loss. Compared with the motion phase error, the SPE takes on a much stronger spatial-variation both in along-track and across-track orientations, and its anisotropic feature makes the compensation more intractable. In this article, the phase gradient autofocus (PGA) is used for the first time to compensate the spatial-varying and anisotropic SPE for spaceborne SAR images. It begins with achieving a reliable SPE estimate by applying PGA to a strong scatterer. According to the preknowledge of the phase screen altitude and the anisotropic elongation heading, the emphasis is then on estimating the SPEs for other pixels from the well-estimated SPE, based on the mutual correlation and overlapping of SPEs. The pixel-by-pixel strategy is adopted for the final compensation. The proposed methodology is very appropriate for SAR images with few corner reflectors, which is validated on a simulated L-band stripmap data and a PALSAR-2 spotlight real data. It shows more powerful utility than the classical PGA. The performance analysis is implemented with regard to two necessary factors, which further confirms the effectiveness of the proposed methodology.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Compressive Sensing Technique for Mitigating Nonlinear Memory Effects in
           Radar Receivers

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      Authors: Euan Ward;Shahzad Gishkori;Bernard Mulgrew;
      Pages: 1005 - 1020
      Abstract: Receiver nonlinearities pose a serious risk to the functionality of modern radars as they can compromise the sensor’s immunity to interfering signals. With the radio frequency (RF) spectrum becoming increasingly crowded, it is now more important than ever that the sensor can maintain system performance when exposed to mutual interference. In this article, we present a nonlinear compressive sensing (NCS) solution, which, unlike the standard nonlinear equalization (NLEQ) techniques, is designed around the forward nonlinearity rather than the inverse. Importantly, in this article, the NCS theory is extended to include nonlinear memory. Furthermore, a radar-specific formalization is derived, which allows the nonlinear optimization to exploit the unique properties of pulsed-Doppler radar processing. As a result, the NCS solution can successfully restore system sensitivity back to the linear case when in-band interference drives the radar receiver into its nonlinear regime. Additionally, it is shown that the technique can consistently mitigate complex nonlinear memory effects generated in the RF receiver. This is a significant result as it proves that forward modeling techniques are a viable alternative to NLEQ. This is of particular importance to radar systems as they provide a far more explicit formalization to mitigate nonlinear memory effects.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Detection of Radio-Frequency Electronics by Stimulated Emission of Carrier
           Modulation

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      Authors: Gregory James Mazzaro;
      Pages: 1021 - 1028
      Abstract: Carrier modulation, a variant of intermodulation distortion, is described and exploited for the remote detection of radio-frequency (RF) electronics. To generate carrier modulation, a single frequency illuminates an electronic device, which is actively transmitting, and mixing of the applied probe tone with the device's emission produces intermodulation distortion. Theory predicts that carrier modulation is detectable from an emitter at a greater distance away from a radar than the traditional intermodulation distortion. Benchtop measurements taken using commercial RF electronic devices confirm this theory. The experiments demonstrate that carrier modulation may be stimulated remotely from a variety of RF electronics. The spectrum of the distortion may be used to pinpoint an emitter's frequency-of-operation.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Analysis of Guidance Laws With Nonmonotonic Line-of-Sight Rate Convergence

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      Authors: Seokwon Lee;Namhoon Cho;Hyo-Sang Shin;
      Pages: 1029 - 1041
      Abstract: This article presents analyses of guidance laws that involve nonmonotonic convergence in heading error from a new perspective based on an advanced stability concept. Pure proportional navigation with range-varying navigation gain is considered, and the gain condition to guarantee asymptotic convergence to the collision course is investigated while allowing the heading error to exhibit patterns that involve intermediate diversion. The extended stability criterion considered in this study allows local increase of the Lyapunov function in some finite intervals, which is less conservative than the standard Lyapunov stability theorem. The existing guidance laws involving intentional modulation of the heading error as well as the design of the navigation gain are discussed with respect to the new stability criterion.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Augmented Nonlinear Least Squares Estimation With Applications to
           Localization

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      Authors: Qin Li;Jian Lan;Le Zhang;Badong Chen;Kaijian Zhu;
      Pages: 1042 - 1054
      Abstract: Least squares (LS) estimation is simple yet effective for parameter estimation. Most real-world problems are nonlinear. In practice, nonlinear LS problems are linearized first and then solved by a linear LS estimator. However, since these methods solve a nonlinear LS problem by a linear way, there is room for improvement only if estimators being nonlinear in the original measurement. In this article, an LS approach is proposed for nonlinear LS problems, along with theoretical analysis and justification. First, for a general nonlinear measurement model with any form of noise, a unified linearization (UL) approach is proposed under certain assumptions and a linearized least squares (LLS) estimator is defined based on the UL model. Second, an augmented nonlinear least squares (ANLS) estimator is proposed based on LLS estimation. In the ANLS estimator, the original measurement is augmented by its nonlinear conversion intended to further utilize the nonlinear measurement. Moreover, we prove that the ANLS estimator outperforms LLS estimation-based estimators. Finally, the UL and the ANLS estimator are applied to source localization with time difference of arrival and/or frequency difference of arrival measurement, and a two-step ANLS localization algorithm is developed. The performance of the proposed algorithm is evaluated via simulation of some typical localization scenarios.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Flexible Task Scheduling in Data Relay Satellite Networks

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      Authors: Guohua Wu;Qizhang Luo;Yanqi Zhu;Xinjiang Chen;Yanghe Feng;Witold Pedrycz;
      Pages: 1055 - 1068
      Abstract: The task-schedulingalgorithm is a key module to satisfy various complex user requirements, and improve the usage flexibility and efficiency of data relay satellites networks (DRSN). In this context, we first propose a novel application mode for DRSN, in which users are allowed to submit multiple optional service time windows and specify a preferred antenna as well as an expected execution duration for each task. Meanwhile, the start time of a service time window can be adjusted within a specified range. A mathematical programming model that maximizes the completion ratio of tasks and the expectation satisfaction of users is established. Moreover, a conflict resolution-assisted iterative task-scheduling algorithm (CRITS) is designed, composing of five closely dependent operators: resource matching, service durations generation, conflict evaluation, conflict resolution, and solution update. To verify the effectiveness of the proposed CRITS, extensive experiments are carried out. The experimental results demonstrate the competitive performance of CRITS in addressing the DRSN scheduling problem. In comparison with two heuristic algorithms (heuristic algorithm based on time-freedom degree and a heuristic algorithm based on task priority) and a meta-heuristic algorithm (adaptive variable neighborhood descent combined with a tabu list), the proposed CRITS increases the overall completion ratio of tasks by 6.65, 10.26, and 10.96%, respectively.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Adaptive Fault-Tolerant Distributed Formation Control of Clustered
           Vertical Takeoff and Landing UAVs

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      Authors: Yao Zou;Kewei Xia;Wei He;
      Pages: 1069 - 1082
      Abstract: This article investigates the formation control issue of clustered vertical takeoff and landing (VTOL) unmanned airborne vehicles (UAVs) subject to undesired perturbations composed by actuator faults, parametric uncertainties, and external disturbances. In particular, a cluster of VTOL UAVs fly together in a given velocity with a well-specified formation configuration. For this purpose, an adaptive fault-tolerant distributed control algorithm via local information interaction is proposed under a hierarchical framework. Specifically, a distributed command force resorting to projection-based adaptation is first synthesized in the outer position loop. Such a command force is of a saturation attribute in order that a boundeddesired thrust and a nonsingular command attitude can be extracted in terms of appropriate control parameters. Next, in the inner attitude loop, a desired torque also with the help of projection-based adaptation is synthesized. Given that the underlying undirected topology is connected, it is shown based on the Lyapunov theory that the proposed adaptive fault-tolerant distributed control algorithm ensures the accomplishment of the concerned formation control objective of the clustered VTOL UAVs in spite of the undesired perturbations. Simulations validate and further highlight the effectiveness of the proposed distributed control algorithm.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Prescribed Performance-Based Powered Descent Guidance for Step-Shaped
           Hazardous Terrains

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      Authors: Youmin Gong;Yanning Guo;Guangfu Ma;Yao Zhang;Minwen Guo;
      Pages: 1083 - 1095
      Abstract: The planetary powered descent guidance problem for step-shaped hazardous terrains is investigated in this article based on prescribed performance function (PPF) methodology. Initially, the distances between the lander and step-shaped terrains around the landing site have been formulated in a new form boundaryfunction using PPF, in which a new step-shaped boundary PPF is specifically designed to constrain the lateral motion. Furthermore, a fixed-time convergent PPF is chosen to coordinate the vertical motion. Next, to avoid the collision with step-shaped terrains and planetary surface, a feedback guidance algorithm is proposed based on the backstepping method. Considering a large guidance gain is beneficial for the lander to move away from the boundary PPF, but excessive control acceleration will be generated when the landing error is large. To solve this problem, an adaptive guidance gain is designed using Gaussian function. Finally, the feasibility and effectiveness of the proposed algorithm have been verified through typical numerical simulations inspired by realistic Martian terrains. Moreover, this attempt using PPF methodology here can be easily reformulated to adjust the powered descent problem with collision avoidance for a flat surface or glide-slope constraint.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Composite Guidance for Impact Time Control Under Physical Constraints

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      Authors: Hyeong-Geun Kim;Hyeonbeom Lee;
      Pages: 1096 - 1108
      Abstract: This article presents a composite guidance law comprising a three-stage proportional navigation (PN) structure for the simultaneous arrival of multiple missiles. Motivated by the fact that the selection of the navigation constant considerably influences the trajectory shape, the proposed composite law is designed to have different navigation constants at each stage to achieve the desired impact time. The three stages of the proposed law are configured to sequentially increase, maintain, and decrease the magnitude of the look angle by switching only the navigation constant, through which the seeker’s field-of-view constraint, which is mainly determined by the look angle, can be satisfied without additional considerations. Furthermore, the simple PN-based structure of the proposed law makes it possible to obtain an exact closed-loop solution, providing various useful information for practical implementation, such as the expected trajectory, required guidance command, and range of achievable impact time. In addition, the relevant investigations based on the theoretical analysis as well as the demonstration results obtained through the numerical simulation are presented herein.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Clustering Methods for Particle Filters With Gaussian Mixture Models

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      Authors: Sehyun Yun;Renato Zanetti;
      Pages: 1109 - 1118
      Abstract: New clustering methods are proposed to develop novel particle filters with Gaussian mixture models (PFGMM). In the PFGMM, the propagated samples are clustered to recover a Gaussian mixture model (GMM) using a clustering algorithm, which plays a fundamental role in the filter’s performance. Two clustering methods are introduced that simultaneously minimize the covariance of each of the GMM components and maximize the likelihood function. Under the scenarios considered in this article, it is shown through numerical simulation that the PFGMMs with the proposed clustering algorithms lead to better performance than the PFGMM employing the K-means or the expectation-maximization algorithms as well as the regularized particle filter (PF) and the Gaussian sum PF.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Economic Model-Predictive Control for Aircraft Forced Landing: Framework
           and Two-Level Implementation

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      Authors: Zihang Dong;Jingjing Jiang;Cunjia Liu;Matthew Coombes;Wen-Hua Chen;
      Pages: 1119 - 1132
      Abstract: This article presents an optimization-based control framework for the autonomous forced landing of a fixed-wing unmanned aircraft (UA). A two-level model-predictive control (MPC) scheme is proposed to realize this framework, where an economic model-predictive control (EMPC) in a long piecewise constant fashion is proposed at the high level, while a short fixed-horizon linear time-varying MPC at the low level responds to fast dynamics of UA and tracks the optimal path provided by the high-level controller, alleviating computational burden compared to the high-frequency single-layer MPC scheme. Compared with a single EMPC setup with high sampling frequency, this hierarchical EMPC controller can significantly reduce the computational complexity and make it feasible to be implemented in real time. In addition, it also responds to disturbances (e.g., wind) and aircraft fast dynamics in a timely manner. The recursive feasibility and stability of the high- and low-level MPC schemes are established. The performance of the proposed EMPC forced landing function is illustrated by simulation case studies on both Aerosonde and Skywalker X8, compared favorably with competing schemes.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Constrained Contextual Bandit Learning for Adaptive Radar Waveform
           Selection

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      Authors: Charles E. Thornton;R. Michael Buehrer;Anthony F. Martone;
      Pages: 1133 - 1148
      Abstract: A sequential decision process in which an adaptive radar system repeatedly interacts with a finite-state target channel is studied. The radar is capable of passively sensing the spectrum at regular intervals, which provides side information for the waveform selection process. The radar transmitter uses the sequence of spectrum observations as well as feedback from a collocated receiver to select waveforms which accurately estimate target parameters. It is shown that the waveform selection problem can be effectively addressed using a linear contextual bandit formulation in a manner that is both computationally feasible and sample efficient. Stochastic and adversarial linear contextual bandit models are introduced, allowing the radar to achieve effective performance in broad classes of physical environments. Simulations in a radar-communication coexistence scenario, as well as in an adversarial radar-jammer scenario, demonstrate that the proposed formulation provides a substantial improvement in target detection performance when Thompson sampling and EXP3 algorithms are used to drive the waveform selection process. Further, it is shown that the harmful impacts of pulse-agile behavior on coherently processed radar data can be mitigated by adopting a time-varying constraint on the radar’s waveform catalog.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • A Parametric Approach to Space-Time Adaptive Processing in Bistatic Radar
           Systems

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      Authors: Jacob Klintberg;Tomas McKelvey;Patrik Dammert;
      Pages: 1149 - 1160
      Abstract: Space-time adaptive processing (STAP) is an important airborne radar technique used to improve target detection in environments of clutter and jammers. Effective STAP implementations are dependent on an accurate estimate of the space-time covariance matrix, which characterizes noise and interference in the radar signal. Inside-looking monostatic radar systems, the estimate based on secondary radar observations is rather straight forward as all the samples in secondary data can be argued to be from a single distribution, and the sample covariance can be used as an estimate of the space-time covariance matrix. However, in many other radar configurations, the vital underlying STAP training assumption that secondary data are identically distributed is violated, which implies that detection performance can be significantly degraded. This article develops a new method that can be used when secondary data do not share a common distribution due to geometry-induced range dependencies. This phenomenon is of particular concern in bistatic radar systems. We propose a model-based approach, where the distribution of noise and clutter for each range bin is parameterized by a set of scenario parameters. Using secondary data, the scenario parameters are estimated by maximizing the likelihood function. Based on the estimated scenario parameters, the STAP covariance estimate is formed for the cell under test. The presented method is compared with other state-of-the-art methods for bistatic radar STAP via numerical simulations. The simulations indicate that the presented method, with a proper initialization, yields an estimate of the STAP covariance matrix that significantly increases the signal-to-interference-plus-noise ratio compared to the other investigated methods.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Cooperative Game Method for On-Orbit Substructure Transportation Using
           Modular Robots

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      Authors: Nan Han;Jianjun Luo;Lijun Zong;
      Pages: 1161 - 1175
      Abstract: This article studies the problem of cooperative substructure transportation using multiple modular robots in an on-orbit assembly mission. Two kinds of modular robots, termed as force and torque robots, are used to provide control forces and torque for the substructure, respectively. Using the framework of cooperative games, a set of Pareto optimal control problems are formulated to solve for the optimal control forces and torque of modular robots, such that they can cooperatively bring the substructure to dock with the main body of a large space structure. Additionally, an event-triggered coordinated compensatory control mechanism using the model predictive control principles is designed for modular robots, which guarantees that the substructure can follow the desired optimal trajectories with the computation and communication burden of modular robots being reduced. Numerical simulations demonstrate the effectiveness of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Pursuer Aim Identification for an Aircraft Formation Using a Passive
           Sensor Without State Estimation

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      Authors: Zijiao Tian;Kaipei Yang;Meir Danino;Yaakov Bar-Shalom;Benny Milgrom;
      Pages: 1176 - 1186
      Abstract: In a pursuit evasion scenario, a missile (pursuer) launched from the ground or the air aims to intercept an aircraft (evader) flying in formation. This article considers the problem of whether an aircraft is aimed by a missile or not, based only on the line-of-sight (LOS) measurements from an on-board passive sensor. The motion of the missile is assumed to be governed by pure proportional navigation guidance. Previous works on this problem estimate the missile’s state motion parameters, which, for a passive sensor, requires a numerical search, i.e., significant computation time, algorithm complexity and is ill-conditioned. We present a methodology that relies on the geometric relationship between the aircraft and the missile without state estimation. A plane is defined by the aircraft velocity vector and one aircraft-to-missile LOS vector, and if a second LOS vector at a subsequent time is in this plane, it is known that the missile aims at the aircraft. A coplanarity test is designed on the basis of these three vectors. We then provide a test statistic for inferring whether the airplane is aimed by the missile. An approximate distribution is used to set the threshold for detection and false alarm probabilities. Simulation results are presented for surface-to-air and air-to-air missile scenarios to illustrate the efficiency of the proposed method and compared to the state estimation method.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Robust Copula-Based Detection of Shallow-Buried Landmines With
           Forward-Looking Radar

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      Authors: Afief Dias Pambudi;Fauzia Ahmad;Abdelhak M. Zoubir;
      Pages: 1187 - 1198
      Abstract: We propose a technique for landmine detection using forward-looking ground-penetrating radar. The detector is applied to radar images obtained from multiple viewpoints of the region of interest and is based on a robust version of the likelihood ratio test (LRT). We incorporate the statistical dependence between multiview images into the test via copula-based model. The test is designed to maximize the worst-case performance over all feasible pairs of target and clutter distributions, thereby eliminating the need for strong assumptions about the image statistics. We evaluate the detection performance of the proposed technique for different copula functions representing the dependence structure. Using electromagnetic modeled data of shallow-buried targets under varying ground surface roughness profiles, we demonstrate the superiority of the robust copula-based detector over existing parametric and robust LRT approaches designed under the assumption of statistical independence of multiview images.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Increased Robustness to Delay in Incremental Controllers Using Input
           Scaling Gain

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      Authors: Rafael A. Cordeiro;Apolo S. Marton;José R. Azinheira;José R. H. Carvalho;Alexandra Moutinho;
      Pages: 1199 - 1210
      Abstract: The main advantage of the incremental dynamics formulation is its property of replacing state-dependent aspects of the system dynamics by measurements, solely requiring modeling the input-dependent dynamics. However, incremental controllers assume that state derivative measurements are available. The lack of accurate sensors and communication delay may appear as limitations for the use of incremental techniques. This article applies a second-order differentiator (SOD) for estimating state derivatives and attenuate measurement noise, and an input scaling gain (ISG) for attenuating the effects of high-frequency noise and delay in the feedback loop. A complete analysis of the combined solution is carried out using an incremental nonlinear dynamic inversion (INDI) strategy. First, a simple linear single-input single-output model is used to evaluate the influence of design parameters in the closed-loop response and stability. Then, the combined SOD and ISG approach is illustrated in a more complex case application, where INDI is used to control the lateral motion of an autonomous airship, results of which corroborate the ISG as an asset to increase the maximum delay allowed in the feedback loop.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Particle Swarm Optimization for Magnetometer Calibration With Rotation
           Axis Fitting Using In-Orbit Data

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      Authors: Bagus Adiwiluhung Riwanto;Petri Niemelä;Hendrik Ehrpais;Andris Slavinskis;Muhammad Rizwan Mughal;Jaan Praks;
      Pages: 1211 - 1223
      Abstract: This article demonstrates the performance of an improved particle swarm optimization (PSO) algorithm with scalar checking and rotation axis fitting objectives using in-orbit data, which is obtained from two CubeSats missions, Aalto-1 and ESTCube-1, as well as simulation as reference. The improved algorithm uses sequential objectives refinement process to combine the two optimization objectives. This improvement addresses some challenges of magnetometer calibration when using in-orbit data. First, the change in the magnetic field vector direction at different points in orbit which is uncorrelated to the rotation of the spacecraft itself. Second, the uncertainty of the rotation axis information used as the reference, e.g., from gyroscope noise. Third, the available data set is heavily affected by the rotation mode of the spacecraft, which imposes some limitation in the rotation axis information needed by the algorithm. The improved PSO algorithm is applied on simulated data in order to analyze the calibration performance under different spacecraft tumbling rates and noise levels. In ideal condition (varying rotation axis during measurements and sufficient sampling rate relative to the spin rate), the rotation axis fitting objective can reach ∼0.1° of correction accuracy.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Protecting GNSS Open Service Navigation Message Authentication Against
           Distance-Decreasing Attacks

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      Authors: Kewei Zhang;Erik G. Larsson;Panos Papadimitratos;
      Pages: 1224 - 1240
      Abstract: As the security of global navigation satellite systems (GNSSs) for civilian usage is increasingly important, navigation message authentication (NMA) significantly improves resilience to spoofing attacks. However, not all attacks can be effectively countered: a strong variant of replay/relay attacks, distance-decreasing (DD) attacks, can shorten pseudorange measurements, without manipulating the cryptographically protected navigation message, thus manipulating the position, velocity, and time solution undetected. First, we discuss how DD attacks can tamper with GNSS signals, demonstrating the attack effectiveness on a recorded Galileo signal. DD attacks might introduce bit errors to the forged signals, but the adversary can keep this error rate very low with proper attack parameter settings. Then, based on our mathematical model of the prompt correlator output of the tracking phase at the victim receiver, we find that the correlator output distribution changes in the presence of DD attacks. This leads us to apply hypothesis testing to detect DD attacks, notably a goodness-of-fit (GoF) test and a generalized likelihood ratio test (GLRT), depending on the victim’s knowledge on the DD attacks. Monte Carlo simulations are used to evaluate the detection probability and the receiver operating characteristic curves for two tests, for different adversary configuration and noise settings. Then, we evaluate the effectiveness of the GoF test and the GLRT with a synthesized DD signal. Both tests can detect DD attacks with similar performance in high-signal-to-noise-ratio (SNR) environments. The GLRT detection probability is approximately 20% higher than that of the GoF test in low-SNR environments.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Correlated Noncoherent Radar Detection for Gamma- Fluctuating Targets in
           Compound Clutter

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      Authors: Josef Zuk;
      Pages: 1241 - 1256
      Abstract: This article studies the problem of radar detection of correlated gamma-fluctuating targets in the presence of clutter described by compound models with correlated speckle. It models signals from a pulsed radar with pulse-to-pulse correlation of components of the range-gated returns from a target with added thermal noise and compound Gaussian clutter. If the correlation is not accounted for in a radar model, the required signal-to-interference ratio as predicted by the model for a given probability of detection will be incorrect, resulting in overestimated performance. Although more generally applicable, the focus of this article is on airborne maritime radar systems. Hence, $K$-distributed sea clutter is used as the main example. Detection via square-law noncoherent pulse integration is formulated in a way that accommodates arbitrary partial correlation for both target radar cross section (RCS) and clutter speckle. The obstacle to including this degree of generality in previous work was the fact that Swerling’s original characterization of the standard RCS fluctuation classes based on specifying distributions for the power is not sufficient to accommodate inclusion of both sources of correlated returns (i.e., target and clutter speckle) in the case of gamma-fluctuating targets. An extension of the model is required at the quadrature component (i.e., voltage) level, as phase relationships can no longer be neglected. This is addressed in the present article, which not only postulates an extended model, but also demonstrates how to efficiently compute it, with and without a number of simplifying approximation schemes within the framework of the saddle-point technique.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Attitude Reconstruction From Inertial Measurement: Mitigating Runge Effect
           for Dynamic Applications

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      Authors: Yuanxin Wu;Maoran Zhu;
      Pages: 1257 - 1265
      Abstract: Time-equispaced inertial measurements are practically used as inputs for motion determination. Polynomial interpolation is a common technique of recovering the gyroscope signal but is subject to a fundamentally numerical stability problem due to the Runge effect on equispaced samples. This article reviews the theoretical results of Runge phenomenon in related areas and proposes a straightforward borrowing-and-cutting (BAC) strategy to depress it. It employs the neighboring samples for higher order polynomial interpolation but only uses the middle polynomial segment in the actual time interval. The BAC strategy has been incorporated into attitude computation by functional iteration, leading to accuracy benefit of several orders of magnitude under the classical coning motion. It would potentially bring significant benefits to the inertial navigation computation under sustained dynamic motions.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • AIS Data Aided Rayleigh CFAR Ship Detection Algorithm of Multiple-Target
           Environment in SAR Images

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      Authors: Jiaqiu Ai;Zhilin Pei;Baidong Yao;Zhaocheng Wang;Mengdao Xing;
      Pages: 1266 - 1282
      Abstract: This article proposes an automatic identification system (AIS) data aided Rayleigh constant false alarm rate (AIS-RCFAR) ship detection algorithm of multiple-target environment in synthetic aperture radar (SAR) images. This method aims to improve the detection performance in complex environment with the aid of AIS data. Traditional CFAR detectors generally use all the samples in the local background window for parameter estimation. However, in multiple-target environment, clutter edges and transition areas, due to the interference of the high-intensity outliers, such as target pixels, ghosts, and other interfering pixels, the parameters are often overestimated, causing degradation of the detection performance. Aiming at solving this problem, AIS-RCFAR designs an adaptive-threshold based clutter trimming method with an adaptive-trimming-depth aided by AIS data to effectively eliminate the high-intensity outliers in the local background window while greatly sustaining the real sea clutter samples. Maximum-likelihood-estimator with a closed-form solution is proposed to precisely estimate the parameters using the adaptively-trimmed clutter samples, the probability density function of the sea clutter following Rayleigh distribution can be accurately modeled. AIS-RCFAR greatly enhances the detection rate in both homogeneous and nonhomogeneous multiple-target environment, it also achieves a very low false alarm rate. In addition, the whole procedure of AIS-RCFAR is simple and efficient. Simulated data and real SAR images with corresponding matched AIS data are used for experiments to validate the superiority and feasibility of AIS-RCFAR.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Adaptive Mutual Coupling Compensation Method for Airborne STAP Radar With
           End-Fire Array

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      Authors: Yuanyi Xiong;Wenchong Xie;
      Pages: 1283 - 1298
      Abstract: Because the maximum radiation direction of the end-fire array antenna points to the axis of the array and the small element spacing required to suppress the grating lobes, the mutual coupling effect between the arrays is more serious than that of the broadside array. The article first established the end-fire array antenna pattern model and clutter signal model with the effect of mutual coupling. The clutter signal model includes two cases, ideal mutual coupling effect and mutual coupling error. On this basis, we take a ten-element uniform linear array using CST Microwave Studio to validate our model. Then we analyze the clutter distribution characteristics of the end-fire array airborne radar and the effect of mismatch on the spatial steering vector. Finally, an adaptive mutual coupling compensation method based on covariance matrix reconstruction is proposed. In general, clutter suppression methods with end-fire array take no account of the mutual coupling error changing over time, but the proposed method first adaptively estimates the mutual coupling error based on the airborne radar echo data and uses the estimated normalized impedance matrix to compensate the spatial steering vector, then combines the system parameters to construct the clutter covariance matrix. The simulations indicate that this method accurately estimate the impedance matrix, and it eliminates the clutter power reduction and spatial steering vector mismatch caused by mutual coupling error. Moreover, it also solves the serious non-stationary clutter problem of the end-fire array airborne radar.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Calibration of the Cylindrical Polarimetric Phased Array Radar via
           GPS-Disciplined Bistatic Pattern Measurement

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      Authors: Matthew M. Herndon;Mark B. Yeary;
      Pages: 1299 - 1315
      Abstract: The cylindrical polarimetric phased array radar (CPPAR) project acts as a case study in cylindrical array design for applications in dual-polarized weather radar, allowing fundamental research such as beamformer optimization and weather measurement verification to be conducted. Developed at the University of Oklahoma’s Advanced Radar Research Center (ARRC), the CPPAR system relies on GPS-disciplined reference clocks for its transceivers and nearly synchronous triggering to transmit and receive bistatically from an isolated measurement horn located in the main array’s far-field, allowing the array’s element and beam patterns to be measured. This measurement scheme introduces phase distortion resulting from time-varying differences between the two reference clocks’ frequencies, a phenomenon which adds a time-varying bias to baseband phase measurements, rendering them unusable without significant post-processing. In this article, our approach to managing this and other measurement-specific challenges is detailed. To provide appropriate background information, the CPPAR’s relevant high-level system design, control systems, and theory is also discussed. Lastly, our method for deriving array bias terms from measured element patterns is detailed. The procedures outlined in this article were successfully deployed to measure element patterns and in turn derive power and phase calibration weights for the system, which ultimately allowed for the completion of two major experiments using the platform.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Optimal Vehicle-Target Assignment: A Swarm of Pursuers to Intercept
           Maneuvering Evaders Based on Ideal Proportional Navigation

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      Authors: M. Mehdi Asadi;Luca Giovanni Gianoli;David Saussié;
      Pages: 1316 - 1332
      Abstract: The problem of vehicle-target assignment (VTA) to capture a team of evading targets using a swarm of pursuing vehicles is investigated in this article. The VTA problem is formulated as an integer linear programming (ILP), such that the time to intercept all the targets is minimized subject to a number of constraints. To obtain closed-form formulas for the time-to-go matrix in the framework of ILP optimization, a one-on-one pursuit-evasion problem based on the ideal proportional navigation (IPN) guidance law is investigated. By considering two different scenarios of non-maneuvering and maneuvering evaders, analytical closed-form solutions for the pursuit-evasion time-to-go as explicit functions of the position and velocity vectors of the pursuers and evaders are developed, and efficient evasion strategies based on IPN guidance scheme are presented. The efficacy of the theoretical results in estimating the elements of time-to-go matrix is demonstrated by solving the VTA problem in simulations.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Robust Multiple Model Predictive Control for Ascent Trajectory Tracking of
           Aerospace Vehicles

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      Authors: Rui Cao;Yanbin Liu;Yuping Lu;
      Pages: 1333 - 1351
      Abstract: For aerospace vehicles with uncertainty, strong nonlinearity, and high-performance requirements, the model predictive control (MPC) method has attracted many researchers’ attention with its unique advantages. Although this method has a good effect, it is computationally expensive, especially for the nonlinear MPC. In addition, it cannot guarantee the stability performance requirements and limited flexibility in dealing with large initial errors. To overcome these limitations, this article is implemented to obtain a control scheme that can handle uncertainty, initial deviation, and has less online calculation. To ensure the stability requirements, the guardian maps (GM) theory is combined with multimodel predictive control, and a switching rule based on GM is proposed. Then, fully considering the characteristics of linear matrix inequalities used, the idea of “offline design and online optimization” is adopted to solve the control law, which reduces the burden of online computing. Furthermore, in the case of large initial errors, a transient trajectory design method is established to reconstruct the trajectory online, and to modify the tracking command. Simulation results verify the effectiveness of the designed control scheme.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Fixed-Time Terminal Angle-Constrained Cooperative Guidance Law Against
           Maneuvering Target

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      Authors: Wei Dong;Chunyan Wang;Jianan Wang;Zongyu Zuo;Jiayuan Shan;
      Pages: 1352 - 1366
      Abstract: In this article, fixed-time cooperative guidance laws are designed for multiple missiles to simultaneously attack a maneuvering target at desired terminal angles. The 3-D guidance commands consist of tangential acceleration along line-of-sight (LOS) direction to achieve a salvo attack and normal acceleration perpendicular to the LOS direction to realize a terminal angle-constrained interception. First, the tangential acceleration is derived from a distributed cooperative protocol to guarantee the fixed-time consensus of impact times for multiple missiles. Second, based on the integral sliding manifold and fixed-time reaching law, the normal acceleration is developed for each missile to converge the LOS angle to the desired value within a fixed time. In particular, the unknown target acceleration components are estimated by fixed-time observers and compensated in the guidance commands. The fixed-time stability of the proposed cooperative guidance law is rigorously proved and the explicit estimate for the convergence time is theoretically provided. Then, the proposed methods are utilized to realize the cooperative mission in the planar guidance scenario. Finally, the effectiveness and advantages of the proposed cooperative guidance laws are demonstrated through numerical simulations with comparative studies.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • A Minimal Architecture for Real-Time Lunar Surface Positioning Using Joint
           Doppler and Ranging

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      Authors: William W. Jun;Kar-Ming Cheung;Edgar Glenn Lightsey;Charles Lee;
      Pages: 1367 - 1376
      Abstract: A positioning solution for users on the lunar surface is required for the success of upcoming missions. Technological advancements have enabled the use of accurate range and Doppler measurements from a lunar orbiter. This article introduces a filtered approach of joint Doppler and ranging (JDR), a minimal architecture that requires as few as one lunar orbiter to perform 3D positioning of lunar surface vehicles. The simulated performance of JDR and Doppler-based positioning methods is compared. Two lunar satellites are simulated: The lunar relay satellite (LRS) in a 12-h frozen orbit with its apogee above the lunar south pole, and the lunar reconnaissance orbiter in a 2-h Polar orbit. The analysis interval is 8 h over a single LRS ground pass. The ground pass has only a few intervals where both satellites are visible to the user and reference station on the lunar south pole. Navigation nodes are simulated with synchronized clocks for all methods. Measurement and satellite ephemeris errors are embedded into a Monte Carlo simulation to evaluate 3D positioning error. The relative JDR method obtains the lowest and most consistent overall 3D root mean squared error, averaging around 10–15 m. The absolute positioning methods are limited by satellite orbit height and other factors. Ultimately, JDR is able to provide reasonably accurate positioning knowledge to users with a minimal required infrastructure. Though this article introduces JDR on the Moon, the same architecture can be applied for other celestial bodies like Venus, Mars, Titan, and asteroids.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Information-Based Particle Flow With Convergence Control

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      Authors: Kari C. Ward;Kyle J. DeMars;
      Pages: 1377 - 1390
      Abstract: A new formulation of the Gaussian particle flow filter is presented using an information theoretic approach. The developed information-based form advances the Gaussian particle flow framework in two ways: it imparts physical meaning to the flow dynamics and provides the ability to easily include modifications for a non-Bayesian update. An orbit determination simulation with high initial uncertainty is used to demonstrate the consistent, robust performance of the information flow filter in situations where the extended Kalman filter fails.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • An Evidential Reasoning Rule Considering Parameter Uncertainty

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      Authors: Jie Wang;Zhi-Jie Zhou;Chang-Hua Hu;Xiao-Xia Han;Shuai-Wen Tang;Peng-Yun Ning;
      Pages: 1391 - 1404
      Abstract: This article aims to propose an evidential reasoning (ER) rule considering the parameter uncertainty. As the essential parameters, the evidence weight and reliability make the ER rule constitute a generalized reasoning framework. Theoretically, the weight is affected by subjective cognition, while the reliability mainly reflects objective variation. However, most of the recent researches have focused on the quantitative calculation methods, which make the differences in the property of the two parameters ignored. In this article, a relatively different idea from previous studies is provided, in which multisource uncertainty of parameters is fully considered. On the one hand, the weight is profiled by interval variable with lower and upper bounds. On the other hand, the reliability is modeled by random variable with probability distribution function. Then, a unified inference model for evidence aggregation is developed based on the inference process of the ER rule. In addition, some basic properties of the model are clearly presented to illustrate the rationality of parameter uncertainty. Finally, a practical example is given to show the potential applications of the proposed model.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Robust Attitude Control Scheme for Constantly Spinning Small-Sized
           Quadrotor in the Presence of Imbalance Characteristics

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      Authors: Hakjun Lee;Seongwon Yoon;Soohee Han;
      Pages: 1405 - 1415
      Abstract: Unlike normal yaw motion, a constantly spinning quadrotor experiences severe instability while rotating at high angular speeds owing to its imbalancecharacteristics originating from the off-center parts. To resolve this issue, this study proposes a novel composite robust control scheme for a constantly spinning quadrotor, with the aim to achieving omnidirectional sensing by scanning its surroundings with a single field of view limited sensor. The proposed scheme makes use of both offline calibration and online disturbance observation to compensate for the variation in the center of mass and misalignment between the body-fixed frame and principal axis of rotation, respectively. Additionally, the reference inputs are reshaped, or leading in time, to achieve the desired flying direction. It is demonstrated through an experiment that the proposed control scheme compensates well for the effect of the imbalance characteristics of the quadrotor, thus achieving good omnidirectional sensing with more stable rotation.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Clutter Rank Analysis in Airborne FDA-MIMO Radar With Range Ambiguity

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      Authors: Keyi Wang;Guisheng Liao;Jingwei Xu;Yuhong Zhang;Lei Huang;
      Pages: 1416 - 1430
      Abstract: Frequency diverse array (FDA), which employs a small frequency increment across its array elements to generate controllable degrees-of-freedom (DOFs) in range dimension, has attracted extensive attentions in recent years. In order to extract and exploit the DOFs in range and angle dimensions, FDA has been combined with multiple-input multiple-output (MIMO) technique, which shows sufficient performance improvement in clutter suppression in scenarios with range ambiguities. Therefore, clutter rank evaluation is an important issue for FDA-MIMO radar mounted on a moving platform. In this article, a clutter rank evaluation criterion is developed with respect to different transmit/receive array configurations and different number of range ambiguities. It is based on a subspace transformation matrix that decouples the clutter subspace and allows a direct determination of clutter rank. With the proposed clutter rank evaluation criterion, the maximum resolvable number of range ambiguities can be determined, which is bounded by the system’s DOFs. Three cases according to different relationships between uniform array element spacings are studied. Then, the aforementioned clutter rank evaluation method is extended to nonuniform array configurations. Moreover, the robustness of the method is studied in the presence of gain-phase errors. Several simulation results are provided to verify the effectiveness of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Three-Dimensional Swarming Using Cyclic Stochastic Optimization

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      Authors: Carsten H. Botts;
      Pages: 1431 - 1445
      Abstract: In this article, we simulate an ensemble of cooperating, mobile sensing agents that implement the cyclic stochastic optimization (CSO) algorithm in an attempt to survey, track, and follow multiple targets. In the CSO algorithm proposed, each agent uses its sensed measurements, its shared information, and its predictions of other agents’ future motion to decide on its next action. This decision is selected to minimize a loss function that decreases as the uncertainty in the target state estimates decreases. Only noisy measurements of this loss function are available to each agent, and, in this study, each agent attempts to minimize this function by calculating its gradient. This article examines, via simulation-based experiments, the implications and applicability of CSO convergence in three dimensions.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Detection of Sea-Surface Small Targets Masked by Range Sidelobes of Large
           Objects

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      Authors: Kun Zhang;Peng-Lang Shui;Yuan Feng;
      Pages: 1446 - 1461
      Abstract: Many high-resolution maritime radars for sea-surface small target detection transmit pulses with large time-bandwidth-products to increase transmitter power and to use the pulse compression technique for high range resolution. On the sea surface, besides small targets of interest, there exist many uninteresting large objects such as big ships, reefs, and offshore platforms for oil production. Large objects have too strong radar returns and their range sidelobes often mask wide range intervals. In these range intervals, masked small targets are difficult to be detected directly. In this article, a complete scheme is proposed to find small targets masked by range sidelobes of large objects in high-resolution maritime radars. In this scheme, high-precision reconstruction of radar returns of large objects is crucial because tiny reconstruction errors are enough to mask weak returns of small targets of interest. An algorithm using the linear programming and oversampled high-resolution range profile model of a large object is given to obtain high-precision reconstruction of the strong radar returns of a large object. From residual radar returns removed the reconstructed strong returns, a near-optimal coherent detector under sea clutter modeled by the spherically invariant random vector with inverse Gamma texture plus colored Gaussian noise is constructed to find masked small targets. Simulated experiments and real measured radar data are used to verify the effectiveness of the proposed scheme and method and reveal their limitations. The results show that the proposed scheme and method are all effective unless small targets fall into the range mainlobe regions of large objects.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • A General Formal Method for Manifold Coverage Analysis of Satellite
           Constellations

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      Authors: Xiaoyu Chen;Zhiming Song;Guangming Dai;Maocai Wang;Emiliano Ortore;Christian Circi;
      Pages: 1462 - 1479
      Abstract: This article studies the problem of analyzing the coverage capacity of satellite constellations with respect to ground regions. The coverage characteristics and formulations are first investigated, and a corresponding symbol system is established. On this basis, the coverage state function and the corresponding extension and intermediate modes for basic coverage analysis problems are defined. By introducing the parameter wildcard characters, the properties of three basic spatial and temporal factors are described. An integrated coverage theory system is constructed accordingly to formalize the general coverage analysis problems in a uniform way, which is versatile and works on representing any type of coverage analysis problems. Additionally, in accordance with the properties of the coverage theory, a boundary function is proposed. The corresponding algorithm framework is also constructed for the calculation of complicated practical coverage analysis problems. Experiments simulating different types of coverage analysis problems are carried out, and results reveal the correctness and the effectiveness of the proposed coverage theory system and algorithm framework.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • Range Sidelobe Level Reduction With a Train of Diverse LFM Pulses

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      Authors: Nadav Neuberger;Risto Vehmas;
      Pages: 1480 - 1486
      Abstract: Target masking is a pervasive problem in radar signal processing: the range sidelobes of the waveform’s matched filter response may cause a strong target to prevent the detection of nearby weaker targets. Common solutions to sidelobe level reduction for frequency-modulated waveforms result in a signal-to-noise ratio (SNR) loss. In this correspondence, we propose a novel method using pulse diversity to reduce the range sidelobes while avoiding an SNR loss. The proposed approach is based on shaping the power spectrum of the summation of a train of constant-amplitude linearly frequency-modulated pulses to resemble a Gaussian function. We present a numerical example demonstrating a drastic sidelobe level reduction. Importantly, our approach avoids any processing SNR loss.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • The First Carrier Phase Tracking and Positioning Results With Starlink LEO
           Satellite Signals

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      Authors: Joe Khalife;Mohammad Neinavaie;Zaher M. Kassas;
      Pages: 1487 - 1491
      Abstract: This letter shows the first carrier phase tracking and positioning results with Starlink’s low earth orbit (LEO) satellite signals. An adaptive Kalman filter based algorithm for tracking the beat carrier phase from the unknown Starlink signals is proposed. Experimental results show carrier phase tracking of six Starlink satellites and a horizontal positioning error of 7.7 m with known receiver altitude.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
  • First Demonstration of the Korean eLoran Accuracy in a Narrow Waterway
           Using Improved ASF Maps

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      Authors: Woohyun Kim;Pyo-Woong Son;Sul Gee Park;Sang Hyun Park;Jiwon Seo;
      Pages: 1492 - 1496
      Abstract: The vulnerabilities of global navigation satellite systems (GNSSs) to radio frequency jamming and spoofing have attracted significant research attention. In particular, the large-scale jamming incidents that occurred in South Korea substantiate the practical importance of implementing a complementary navigation system. This letter briefly summarizes the efforts of South Korea to deploy an enhanced long-range navigation (eLoran) system, which is a terrestrial low-frequency radio navigation system that can complement GNSSs. After four years of research and development, the Korean eLoran testbed system has been recently deployed and is operational since June 1, 2021. Although its initial performance at sea is satisfactory, navigation through a narrow waterway is still challenging because a complete survey of the additional secondary factor (ASF), which is the largest source of error for eLoran, is practically difficult in a narrow waterway. This letter proposes an alternative way to survey the ASF in a narrow waterway and improve the ASF map generation methods. Moreover, the performance of the proposed approach was validated experimentally.
      PubDate: April 2022
      Issue No: Vol. 58, No. 2 (2022)
       
 
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