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Aerospace and Electronic Systems, IEEE Transactions on
Journal Prestige (SJR): 0.611
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  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0018-9251
Published by IEEE Homepage  [191 journals]
  • IEEE Aerospace and Electronic Systems Society
    • 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: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Bistatic SAR: Forecasting Spatial Resolution
    • Authors: William Dower;Mark Yeary;
      Pages: 1584 - 1595
      Abstract: This paper derives closed-form expressions for bistatic synthetic aperture radar (SAR) spatial resolution of a generalized system from the k-space or the wavenumber domain. These spatial resolution equations have not previously appeared in the literature. From these equations, significant resolution is found in range and cross range, forecasting a forward-scatter bistatic SAR image when the elevation angles of each bistatic platform are significantly different. Simulation and laboratory tests demonstrated the forward-scatter resolution.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Initial Orbit Determination Using Very Short Arc Data Based on
           Double-Station Observation
    • Authors: Huatao Shang;Defeng Chen;Huawei Cao;Tuo Fu;Meiguo Gao;
      Pages: 1596 - 1611
      Abstract: A method of initial orbit determination (IOD) of a space object, which uses very short arc (VSA) data of double-station observations, is presented. Closed-form solutions of the initial orbit are derived, and these solutions utilize radial measurements (the range, velocity, and acceleration) from two radar stations. The performance of the method based on the geometric dilution of precision (GDOP) metric is analyzed in detail. The analytical approximation expressions of the GDOP metric are also derived, and these expressions can serve as guidance for choosing an observation arc in order to obtain better IOD performance. Comparison of the analytical results with Monte Carlo simulations shows good consistency. Theoretical analysis and simulation results show that several seconds of VSA data can produce an IOD accuracy of several kilometers in position and several meters per second in velocity, provided that highly accurate measurements of phase-derived velocity and acceleration are available.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Structured Light System on Mars Rover Robotic Arm Instrument
    • Authors: David Arge Klevang Pedersen;Carl Christian Liebe;John Leif Jørgensen;
      Pages: 1612 - 1623
      Abstract: A structured light system is used to position a scientific instrument mounted on a Mars rover robotic arm relative to a Mars surface sample. Fifty laser spots are projected on the Mars surface sample. The identification of individual laser spots, the centroiding algorithm, and the calibration are discussed. Results show that the system measures the distance to the Mars surface sample more accurate than 50 μm at a nominal operating distance of 30 mm.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Classification, Denoising, and Deinterleaving of Pulse Streams With
           Recurrent Neural Networks
    • Authors: Zhang-Meng Liu;Philip S. Yu;
      Pages: 1624 - 1639
      Abstract: Pulse streams of many emitters have flexible features and complicated patterns. They can hardly be identified or further processed from a statistical perspective. In this paper, we introduce recurrent neural networks (RNNs) to mine and exploit long-term temporal patterns in streams and solve problems of sequential pattern classification, denoising, and deinterleaving of pulse streams. RNNs mine temporal patterns from previously collected streams of certain classes via supervised learning. The learned patterns are stored in the trained RNNs, which can then be used to recognize patterns-of-interest in testing streams and categorize them to different classes, and also predict features of upcoming pulses based on features of preceding ones. As predicted features contain sufficient information for distinguishing between pulses-of-interest and noises or interfering pulses, they are then used to solve problems of denoising and deinterleaving of noise-contaminated and aliasing streams. Detailed introductions of the methods, together with explanative simulation results, are presented to describe the procedures and behaviors of the RNNs in solving the aimed problems. Statistical results are provided to show satisfying performances of the proposed methods.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • A Box Particle Filter Method for Tracking Multiple Extended Objects
    • Authors: Allan De Freitas;Lyudmila Mihaylova;Amadou Gning;Marek Schikora;Martin Ulmke;Donka Angelova;Wolfgang Koch;
      Pages: 1640 - 1655
      Abstract: Extended objects generate a variable number of multiple measurements. In contrast with point targets, extended objects are characterized with their size or volume, and orientation. Multiple object tracking is a notoriously challenging problem due to complexities caused by data association. This paper develops a box particle filter (box PF) method for multiple extended object tracking, and for the first time, it is shown how interval-based approaches can deal efficiently with data association problems and reduce the computational complexity of the data association. The box PF relies on the concept of a box particle. A box particle represents a random sample and occupies a controllable rectangular region of nonzero volume in the object state space. A theoretical proof of the generalized likelihood of the box PF for multiple extended objects is given based on a binomial expansion. Next, the performance of the box PF is evaluated using a challenging experiment with the appearance and disappearance of objects within the area of interest, with real laser rangefinder data. The box PF is compared with a state-of-the-art particle filter with point particles. Accurate and robust estimates are obtained with the box PF, both for the kinematic states and extent parameters, with significant reductions in computational complexity. The box PF reduction of computational time is atleast 32% compared with the particle filter working with point particles for the experiment presented. Another advantage of the box PF is its robustness to initialization uncertainty.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Networking in Interstellar Dimensions: Communicating With TRAPPIST-1
    • Authors: Juan Andres Fraire;Marius Feldmann;Felix Walter;Elena Fantino;Scott C. Burleigh;
      Pages: 1656 - 1665
      Abstract: The recent discovery of potentially habitable planets orbiting the TRAPPIST-1 system intensified interest in interstellar exploration. In these challenging mission concepts, communication protocols would need to cope with unprecedented signal propagation delays. In this paper, we propose and explore delay tolerant networking (DTN) technologies and analyze in a case study based on the TRAPPIST-1. Results suggests that DTN protocols features could become a valuable means to achieve data delivery in future interstellar networks.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • ECDSA-Based Message Authentication Scheme for BeiDou-II Navigation
           Satellite System
    • Authors: Zhijun Wu;Rusen Liu;Haijuan Cao;
      Pages: 1666 - 1682
      Abstract: This paper proposes a BeiDou-II navigation message authentication scheme to defend against the generating spoofing attacks. In this scheme, a digital signature is generated by the elliptic curve digital signature algorithm and is inserted into the reserved bits of the BeiDou-II navigation message. This signature will verify the integrity and authenticity of the navigation data to avoid entity masquerade and data tampering. Furthermore, the key exchange process is also designed through the short message service or digital certificate. The effectiveness and security of the scheme is evaluated in the simulation. The results indicate that the authentication of BeiDou-II navigation message can be realized in the harsh environment, and the resistance ability of civil BeiDou-II against a spoofing attack could be enhanced by this scheme.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Far-Field Inversion for the Deep Interior Scanning CubeSat
    • Authors: Mika Takala;Patrick Bambach;Jakob Deller;Esa Vilenius;Manfred Wittig;Harald Lentz;Hans Martin Braun;Mikko Kaasalainen;Sampsa Pursiainen;
      Pages: 1683 - 1697
      Abstract: This study aims at advancing mathematical and computational techniques for reconstructing the interior structure of a small solar system body via computed radar tomography (CRT). We introduce a far-field model for full-wave CRT and validate it numerically for an orbiting distance of 5 km using a synthetic three-dimensional target asteroid and sparse limited-angle data. As a potential future application of the proposed method, we consider the deep interior scanning CubeSat concept in which the goal is to localize macroporosities inside a rubble-pile near-earth asteroid with two small spacecraft carrying a bistatic radar.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Attitude Estimation and Geometry Reconstruction of Satellite Targets Based
           on ISAR Image Sequence Interpretation
    • Authors: Yejian Zhou;Lei Zhang;Yunhe Cao;Zhenhua Wu;
      Pages: 1698 - 1711
      Abstract: Analysis of the attitude and geometry of space targets with the inverse synthetic aperture radar (ISAR) technique is a significant and difficult task. Most of the existing methods hardly consider the radar observation geometry in the determination of target attitude. This paper proposes a novel approach to estimating the three-dimensional attitude and reconstructing typical component geometry of space targets from an ISAR image sequence. The approach bridges range-Doppler images and target attitude parameters with the accommodation of target trajectory information and the ISAR geometric projection model. By exploring the shape feature within the ISAR sequence, the target attitude and the rectangular component size are estimated through solving an optimization with prior shape constraints. Comparative experiments illustrate the advantages of the proposed method in both feature association and reconstruction feasibility. Moreover, considering practical circumstances, a further analysis is made of the robustness of the proposed algorithm after the attitude estimation experiment.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Classifying Multichannel UWB SAR Imagery via Tensor Sparsity Learning
           Techniques
    • Authors: Tiep Huu Vu;Lam H. Nguyen;Vishal Monga;
      Pages: 1712 - 1724
      Abstract: Using low-frequency (UHF to L-band) ultrawideband synthetic aperture radar (SAR) technology for detecting buried and obscured targets, e.g., bomb or mine, has been successfully demonstrated recently. Despite promising recent progress, a significant open challenge is to distinguish obscured targets from other (natural and manmade) clutter sources in the scene. The problem becomes exacerbated in the presence of noisy responses from rough ground surfaces. In this paper, we present three novel sparsity-driven techniques, which not only exploit the subtle features of raw captured data, but also take advantage of the polarization diversity and the aspect angle dependence information from multichannel SAR data. First, the traditional sparse representation-based classification is generalized to exploit shared information of classes and various sparsity structures of tensor coefficients for multichannel data. Corresponding tensor dictionary learning models are consequently proposed to enhance classification accuracy. Finally, a new tensor sparsity model is proposed to model responses from multiple consecutive looks of objects, which is a unique characteristic of the data set we consider. Extensive experimental results on a high-fidelity electromagnetic simulated data set and radar data collected from the U.S. Army Research Laboratory side-looking SAR demonstrate the advantages of proposed tensor sparsity models.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • GP-PDA Filter for Extended Target Tracking With Measurement Origin
           Uncertainty
    • Authors: Yunfei Guo;Yong Li;Ratnasingham Tharmarasa;Thiagalingam Kirubarajan;Murat Efe;Bahadir Sarikaya;
      Pages: 1725 - 1742
      Abstract: Extended target tracking (ETT) is an issue in high-resolution radar surveillance, ship tracking, and video tracking. Most of the previous works focus on tracking an ellipsoidal extended target without measurement origin uncertainty (missed detections and clutter). In this paper, a new estimator called the Gaussian process probabilistic data association (GP-PDA) filter is proposed to track an irregularly shaped extended target with measurement origin uncertainty. First, a generalized measurement model for ETT using the Gaussian process (GP) is presented. Both the interior scattering points and the external clutter are considered in this model. Second, a GP-based gating technique is constructed to select validated measurements to feed the filter. Third, the GP-PDA filter is proposed to simultaneously estimate the kinematic state and the contour state of the extended target with measurement origin uncertainty. It is proven that the GP-PDA is a generalized version of the classic PDA, and the latter is a special case of the former in the point target tracking applications. Finally, the GP-based posterior Cramér-Rao lower bound (PCRLB) is derived to evaluate the performance of the ETT with measurement origin uncertainty. Two cases of the PCRLB are discussed, with the number of scattering points being known and unknown. Simulation results verify the effectiveness of the proposed method.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • UAV Collision Avoidance Based on Varying Cells Strategy
    • Authors: Xiaobin Zhou;Xiang Yu;Xiaoyan Peng;
      Pages: 1743 - 1755
      Abstract: This paper presents a trajectory planning strategy for collision avoidance in unmanned aerial vehicles. First, a varying cell strategy is proposed to integrate aerodynamic constraints into trajectory planning. Basic avoidance actions in the varying cell strategy are adapted accordingly to go through different cells, enabling more flexible avoidance maneuvers. Second, given the limited decision-making time involved, offline and online path planning methods are developed to increase the convergence rate. Finally, Monte Carlo simulations demonstrate that the proposed method satisfies aerodynamic constraints, while both the convergence and collision avoidance rates are better than that achieved by fixed cell-based methods.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • On Bayesian Tracking and Prediction of Radar Cross Section
    • Authors: Michał Meller;
      Pages: 1756 - 1768
      Abstract: We consider the problem of Bayesian tracking of radar cross section. The adopted observation model employs the gamma family, which covers all Swerling cases in a unified framework. State dynamics are modeled using a nonstationary autoregressive gamma process. The principal component of the proposed solution is a nontrivial gamma approximation, applied during the time update recursion. The superior performance of the proposed approach is confirmed using simulations and a real-world dataset.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Tracking of Multiple Targets Using Optimal Number of UAVs
    • Authors: Arun Das;Shahrzad Shirazipourazad;David Hay;Arunabha Sen;
      Pages: 1769 - 1784
      Abstract: In this paper, we study the problem of mobile target tracking using the fewest number of mobile trackers for two different types of targets. Given the target trajectories and the period of observation, we propose techniques to compute the minimum number of trackers and their trajectories required to track all mobile targets. Two classes of mobile targets are considered in this paper: 1) targets that need tracking for the entire duration of observation and 2) targets that need tracking at least once during the period of observation. We show that even when target trajectories are known in advance, the problem is computationally hard, i.e., NP-complete. We formulate the problem as a network flow problem and propose algorithms for its solution. We evaluate the performance of our algorithms through simulation and study the impact of parameters such as the speed and sensing range of the trackers.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Filtering DC Bias in a Hard-Limited Radar Signal Processor Using Code
           Imbalance
    • Authors: Gregory Emmett Coxson;
      Pages: 1785 - 1793
      Abstract: A radar signal processor subchain containing a pulse compression module employing binary ±1 phase codes is studied in an effort to understand the behavior of the output mean and variance as functions of phase code imbalance, in noise-limited environments. It is a relatively simple subchain consisting of an R/Theta limiter, a pulse compressor using a length-N phase code for match filtering, scaling by 1/N, and a squarer (also known as I2 + Q2). The input to this system is a sampled input string assumed to be formed of a small dc bias with added two-dimensional Gaussian noise. The output of this system is studied for a range of values of the pulse compression code imbalance. Imbalance is the difference between the number of 1 and -1 elements in the binary phase code. A nonzero imbalance is sometimes a cause for concern, since the pulse compression dc gain is proportional to the code imbalance. Hence, the dc gain might be expected to yield a nonzero component at the output, resulting in an increased risk of false alarms on a radar return comprised of noise alone. However, we show that for imbalance of ±√N, any contribution from the dc bias is nearly eliminated. When N is a perfect square, dc bias is completely eliminated, in theory at least. Analytical formulae are provided, along with simulation results for pulse compression code length N = 512.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Phase Unwrapping for Bistatic InISAR Imaging of Space Targets
    • Authors: Zhengkun Yuan;Junling Wang;Lizhi Zhao;Di Xiong;Meiguo Gao;
      Pages: 1794 - 1805
      Abstract: In this paper, the spatial-variant property of inverse synthetic aperture radar (ISAR) imaging plane of space targets is exploited for phase unwrapping in bistatic interferometric ISAR (InISAR) imaging of space targets. We utilize the interferometric phases in different orbit arcs to obtain the correct fuzzy factor in a calculated set. The threshold for incorrect fuzzy factor excluding and the orbit arc selection strategy are derived for efficiency. Numerical simulations illustrate the effectiveness of the proposed method.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Gaussian Bounds of Sample Distributions for Integrity Analysis
    • Authors: Juan Blanch;Todd Walter;Per Enge;
      Pages: 1806 - 1815
      Abstract: We present a method to determine Gaussian overbounding distributions used in integrity analysis. This method overcomes the limitations of previous techniques by combining them, through the determination of an intermediate symmetric and unimodal overbounding distribution. This method is the basis of a MATLAB toolset that computes strict Gaussian overbounding distributions for any sample distribution. We apply the method to the determination of the overbounding distribution of the GPS clock and ephemeris errors for the advanced receiver autonomous integrity monitoring.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Machine Learning Methods for Spacecraft Telemetry Mining
    • Authors: Sara K. Ibrahim;Ayman Ahmed;M. Amal Eldin Zeidan;Ibrahim E. Ziedan;
      Pages: 1816 - 1827
      Abstract: Spacecrafts are critical systems that have to survive space environment effects. Due to its complexity, these types of systems are designed in a way to mitigate errors and maneuver the critical situations. Spacecraft delivers to the ground operator an abundance data related to system status telemetry; the telemetry parameters are monitored to indicate spacecraft performance. Recently, researchers proposed using Machine Learning (ML)/Telemetry Mining (TM) techniques for telemetry parameters forecasting. Telemetry processing facilitates the data visualization to enable operators understanding the behavior of the satellite in order to reduce failure risks. In this paper, we introduce a comparison between the different machine learning techniques that can be applied for low earth orbit satellite telemetry mining. The techniques are evaluated on the bases of calculating the prediction accuracy using mean error and correlation estimation. We used telemetry data received from Egyptsat-1 satellite including parameters such as battery temperature, power bus voltage and load current. The research summarizes the performance of processing telemetry data using autoregressive integrated moving average (ARIMA), Multilayer Perceptron (MLP), Recurrent Neural Network (RNN), Long Short-Term Memory Recurrent Neural Network (LSTM RNN), Deep Long Short-Term Memory Recurrent Neural Networks (DLSTM RNNs), Gated Recurrent Unit Recurrent Neural Network (GRU RNN), and Deep Gated Recurrent Unit Recurrent Neural Networks (DGRU RNNs).
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Universal Kriging for Loran ASF Map Generation
    • Authors: Pyo-Woong Son;Joon Hyo Rhee;Jaehui Hwang;Jiwon Seo;
      Pages: 1828 - 1842
      Abstract: After a series of intentional Global Positioning System (GPS) jamming attacks impacted a large area of South Korea, the Ministry of Oceans and Fisheries of South Korea considers long-range navigation (Loran) and enhanced Loran (eLoran) as a maritime backup navigation system. Despite its robustness to signal jamming, the positioning accuracy of Loran/eLoran is lower than that of GPS. Because the signal delay due to the land path, which is called the additional secondary factor (ASF), is the largest unknown component of Loran/eLoran, it is necessary to account for temporal and spatial ASF errors to ensure high accuracy. The generation of ASF maps based on ASF survey data in a service area is the most convenient way to mitigate spatial ASF error, but the quality of ASF maps depends on the applied interpolation algorithm. It is desirable to generate high-quality ASF maps based on ASF measurements at only a few survey points, because extensive ASF surveys are expensive and time consuming and require considerable effort. This paper proposes kriging methods for satisfying this objective and shows their superior performance during a field test in Incheon, Korea. In particular, universal kriging with the proposed drift model showed a better performance than linear interpolation, inverse distance weighing, and ordinary kriging when the test vehicle was close to a coastline. The positioning accuracy with the ASF maps generated by the proposed universal kriging along a 5-km route during the field test was 25.24 m (95%). The land vehicle used for the test experienced significant signal-to-noise ratio (SNR) degradation owing to the noise caused by its engine. A vessel without such SNR degradation is expected to achieve higher accuracy.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Integral Global Sliding Mode Guidance for Impact Angle Control
    • Authors: Shaoming He;Defu Lin;Jiang Wang;
      Pages: 1843 - 1849
      Abstract: This paper proposes a new guidance law based on integral sliding mode control (ISMC) technique for maneuvering target interception with impact angle constraint. A time-varying function weighted line-of-sight error dynamics, representing the nominal guidance performance, is introduced first. The proposed guidance law is derived by utilizing ISMC to follow the desired error dynamics. The convergence of the guidance law developed is supported by Lyapunov stability. Simulations with extensive comparisons explicitly demonstrate the effectiveness of the proposed approach.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • GNSS Integrity Monitoring for Rail Applications: Two-Tiers Method
    • Authors: Cosimo Stallo;Alessandro Neri;Pietro Salvatori;Roberto Capua;Francesco Rispoli;
      Pages: 1850 - 1863
      Abstract: This paper presents an innovative global navigation satellite system (GNSS) fault detection and exclusion approach for the adoption of satellite localization in the rail sector. Current global integrity monitoring systems cannot guarantee the safety level needed for such applications as train control where tolerable hazard rate in the order of 10-9/h is required. A new method, named two tiers, enabling to integrate local augmentation systems and global augmentation infrastructures, is presented. It is based on the comparison of single differences residuals among satellites for detecting signal in space (SIS) faults and double difference residuals among local augmentation stations and satellite-based augmentation systems ranging and integrity monitoring stations for detecting reference stations faults. GPS SIS faults described in literature and real GNSS raw data recorded on a train are taken into account. This study reports the performance analysis for the two-tiers approach carried out during relevant European projects. A test-bed architecture has been developed through the implementation of the algorithm in real time on a local augmentation operational center. Relevant performances have been tested on a rail track for validating the algorithm in real operative conditions. Significant results of the analysis are reported for SIS integrity assessment only.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • A Precoding OFDM MIMO Radar Coexisting With a Communication System
    • Authors: Dan Bao;Guodong Qin;Jingjing Cai;Gaogao Liu;
      Pages: 1864 - 1877
      Abstract: A novel orthogonal frequency-division multiplexing (OFDM) multiple-input multiple-output (MIMO) radar is proposed in this paper in a scenario of coexisting with a communication system. For the purpose of avoiding interference to communication while maintaining MIMO radar's capabilities, such as measuring signal's direction of departure (DOD), a collocated antenna array is divided into several overlapped subarrays. Mutually OFDM waveforms exploiting an orthogonal space-time block code are transmitted through these subarrays to obtain waveform diversity, which can be separated at the radar receiver. A MUSIC-like DOD estimation algorithm and the Cramér-Rao bound of DOD are proposed for overlapped subarrays' configuration in order to evaluate performance of the beamforming strategy. The beamformer is designed using an optimization technique at cost of maximizing the input SNR of radar while keeping communication rate constant. Due to nonconvexity of the optimization problem, a two-step optimization algorithm is proposed. Simulation experiments validate theoretical analysis of the proposed precoding radar. Experiments also show robustness of the precoding scheme and the ability of balancing the input SNR of radar and the communication rate.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Energy Management Strategy for Solar-Powered UAV Long-Endurance Target
           Tracking
    • Authors: Jianfa Wu;Honglun Wang;Yu Huang;Zikang Su;Menghua Zhang;
      Pages: 1878 - 1891
      Abstract: In this study, two types of three-dimensional (3-D) flight-based energy management strategies for solar-powered unmanned aerial vehicle (SUAV) long-endurance target tracking are proposed. In SUAV dynamic modeling, we consider the influence of wind on SUAV kinematics. Aiming at the complexity of the long-endurance tracking, namely the long flight time and space spans, the influences of the wind, variations of temperature, air density and solar cell photovoltaic efficiency, and a finite battery capacity are considered in our modified SUAV energy model. Then, considering the mission flexibility, we design two types of energy management strategies that comprehensively utilize the solar energy, gravitational potential energy, and wind to address different situations. The proposed strategies can be divided into several stages in chronological order according to the solar irradiation conditions, electrical energy storage conditions, and relative motion relationships among the SUAV, target, and wind. We then design respective strategies for these stages. The core of our proposed energy management strategies is to design the corresponding objective functions in each stage and the switching conditions between adjacent stages. Finally, we verify our proposed strategies by comparison with the traditional 2-D tracking strategy in a 24-h target tracking mission, and the results show the validity of our proposed strategies.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Semi-Automated Emergency Landing Site Selection Approach for UAVs
    • Authors: Bulent Ayhan;Chiman Kwan;Yool-Bin Um;Bence Budavari;Jude Larkin;
      Pages: 1892 - 1906
      Abstract: The use of unmanned aerial vehicles (UAV) in military and industry today is becoming more widespread. There are a wide range of UAV models that are functional today. The size of these UAVs can be as small as a hawk and can be as big as a passenger jetliner. It is critical for these UAVs to have contingency plans before flight in case of unexpected situations, such as engine-out events which cause total loss of thrust during flight. An important part of contingency planning is to identify emergency landing sites along the flight path of the UAV. This paper discusses the development of an offline semi-automated approach for finding emergency landing sites in the shape of a rectangular runway to be used in preflight contingency planning. The approach introduces a total of five emergency landing measures and a surface type estimation, which are applied to the identified emergency landing site candidates for their safety assessment. The output is a list of emergency landing site candidates together with their surface type estimates that are ranked from the safest to least safe through a generalized safety score for each surface type. The approach can label the ranked landing site candidates according to their reachability in the presence of wind, given the UAV's altitude and coordinates at the time the total loss of thrust happened and the wind forecast for the area.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • GPS Multireceiver Joint Direct Time Estimation and Spoofer Localization
    • Authors: Sriramya Bhamidipati;Grace Xingxin Gao;
      Pages: 1907 - 1919
      Abstract: We propose a novel algorithm for the joint estimation of spoofer location (LS) and GPS time using multireceiver direct time estimation (MRDTE). To achieve this, we utilize the geometry and known positions of multiple static GPS receivers distributed within the power substation. The direct time estimation computes the most likely clock parameters by evaluating a range of multipeak vector correlations, each of which is constructed via different pregenerated clock candidates. Next, we compare the time-delayed similarity in the identified peaks across the receivers to detect and distinguish the spoofing signals. Later, we localize the spoofer and estimate the GPS time using our joint particle and Kalman filter. Furthermore, we characterize the probability of spoofing detection and false alarm using Neyman Pearson decision rule. Later, we formulate the theoretical Cramér Rao lower bound for estimating the localization accuracy of the spoofer. We validate the robustness of our LS-MRDTE by subjecting the authentic open-sky GPS signals to various simulated spoofing attack scenarios. Our experimental results demonstrate precise localization of the spoofer while simultaneously estimating the GPS time to within the accuracy specified by the power community (IEEE C37.118 standard for synchrophasors).
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Wavelength-Diverse MIMO Radar: Parameter-Coupling, Array-Carrier
           Optimization and Direction-of-Arrival Estimation
    • Authors: Michael Ulrich;Bin Yang;
      Pages: 1920 - 1932
      Abstract: This paper investigates the parameter coupling of range, Doppler, and direction of arrival (DOA) for wavelength diverse (WLD) multiple-input multiple-output (MIMO) radar with time-division multiplexing (TDM). In particular, the Cramér-Rao Bound for such a WLD-MIMO system is calculated and used for a novel array and wavelength design approach. Furthermore, a multitarget DOA estimation algorithm is presented, which can handle the WLD- and TDM-induced parameter coupling. Finally, simulations demonstrate the performance of the proposed method and the benefit over traditional MIMO.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • A Conflict Detection Method for Ellipsoidal Safety Regions
    • Authors: Donald McMenemy;David Sidoti;Krishna Rao Pattipati;Francesco A. N. Palmieri;
      Pages: 1933 - 1944
      Abstract: A novel pairwise comparison algorithm that determines whether a pair of ellipsoids is overlapping, touching, or separated by exploiting two new Mahalanobis distance conditions is presented. These conditions are filtering steps prior to a previously proposed method that transforms the intersection query problem into a least squares minimization over a sphere. The algorithm introduced here is shown to be more computationally efficient than previous methods, which either solve the least squares minimization over a sphere or check the signs of the roots of a fourth order polynomial. The proposed method may be applied in cases when an ellipsoid is an appropriate safety region. The resulting algorithm is useful in applications including, but not limited to, collision detection and avoidance.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Comparing the “Rim” Versus the “Filled” Rectangular Array
           Grids—Their Direction-Finding Cramér-Rao Bounds
    • Authors: Zakayo Ndiku Morris;Kainam Thomas Wong;
      Pages: 1945 - 1956
      Abstract: A rectangular array of sensors is often used in direction finding, due to the geometric regularity in its spatial rectangular grid. The sensor positions may be confined to the rectangle's perimeter (as in a “rim” array), or may span over the rectangle's entire interior as well (as in a “filled” array). This paper compares these two array grids by their precision in direction finding, by pioneering Cramér-Rao bound expressions for both array grids above, in closed forms and explicitly in terms of the array parameters.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Localization Accuracy Model Incorporating Signal Detection Performance for
           Wide Area Multilateration
    • Authors: Junichi Naganawa;Hiromi Miyazaki;Hirohisa Tajima;
      Pages: 1957 - 1971
      Abstract: Wide area multilateration (WAM) estimates aircraft positions on the basis of time difference of arrival (TDOA) for air traffic control. To design the receiver positions, dilution of precision has been used. However, the conventional approach ignores failure in signal detection. Therefore, this paper proposes a novel WAM accuracy model for more realistic performance prediction. The proposed model employs a stochastic constellation, i.e., the constellation of available receivers virtually changes according to the signal detection performance.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Bistatic ISAR Imaging for Nonuniformly Rotating Targets
    • Authors: Byung-Soo Kang;Bo-Hyun Ryu;Kyung-Tae Kim;
      Pages: 1972 - 1988
      Abstract: When a target undergoes nonuniform rotational motion (RM), conventional motion compensation (MOCOM) approaches for monostatic inverse synthetic aperture radar (ISAR) systems fail to correct the nonuniform RM error in bistatic radar systems; this failure is caused by nonlinear phase relationships between scatterers in bistatic ISAR (Bi-ISAR) systems. To address this problem, in this paper, we propose a new MOCOM framework for Bi-ISAR imaging of nonuniformly rotating targets. In the proposed method, a newly devised correction is performed to ensure successful RM compensation, followed by translational motion compensation. Because the phase relationships of the scatterers become virtually linear after this correction, nonuniform RM can be successfully converted into uniform RM. Namely, using the proposed method, translational and rotational motion errors are correctly removed, and focused Bi-ISAR images are obtained even for a target involved in nonuniform RM. Furthermore, for more effective use of Bi-ISAR images, a method to restore sheared Bi-ISAR images is exploited in the proposed framework. In the simulations and experiments, we determined that the proposed method can provide high-quality Bi-ISAR images for nonuniformly rotating targets.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Fault-Tolerant Attitude Stabilization Incorporating Closed-Loop Control
           Allocation Under Actuator Failure
    • Authors: Bo Li;Qinglei Hu;Guangfu Ma;Yongsheng Yang;
      Pages: 1989 - 2000
      Abstract: This paper addresses the difficult problem of fault-tolerant control and closed-loop control allocation for spacecraft attitude control system with actuator failures, actuator saturation, and external disturbances. As a fundamental step, a modified fault diagnosis observer is proposed utilizing the iterative learning methodology to reconstruct the actuator failures in real time. On the basis of the previously reconstructed failure information, a fault-tolerant control scheme incorporating with a parameter adjusting law is presented to enforce the spacecraft attitude control system to reach the real sliding mode surface in finite time. Meanwhile, the singularity of control command will be avoided using the saturation function, and the chattering problem restrained by the adjusting law. Furthermore, with the concept of control allocation, a novel on-line closed-loop constrained optimal fault-tolerant control allocation scheme is employed to distribute the signals synthesized by the baseline controller over the redundant actuators with failures and constraints. The stability of the closed-loop fault-tolerant control allocation process is guaranteed by the theory of the closed-loop discrete-time feedback control system. The key achievement of the proposed systematic strategy is that the whole closed-loop attitude control system can theoretically be guaranteed to be stable. Numerical simulations are carried out to verify the effectiveness and superiority of the developed approach.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Mars Powered Descent Phase Guidance Design Based on Fixed-Time
           Stabilization Technique
    • Authors: Yao Zhang;Ranjan Vepa;Guang Li;Tianyi Zeng;
      Pages: 2001 - 2011
      Abstract: This paper proposes a guidance scheme to achieve an autonomous precision landing on Mars and proposes a practical fixed-time stabilization theorem to analyze the robustness of the guidance. The proposed guidance is mainly based on the fixed-time stabilization method, and it can achieve the precision landing within a pre-defined time. This property enables the proposed guidance to outperform the finite-time stabilization technique which cannot handle uncertainties well and whose convergence time is dependent on initial states. Compared with the existing fixed-time stabilization theorem, the proposed practical fixed-time stabilization theorem can achieve a shorter convergence time and cope with unknown disturbances. When the Mars landing guidance is designed by this proposed theorem, the upper bound of the landing time and the maximum landing error subject to unknown disturbances can be calculated in advance. Theoretical proofs and Monte Carlo simulation results confirm the effectiveness of the proposed theorem and the proposed guidance. Furthermore, the efficacy of the proposed guidance with thrust limitations is also demonstrated by testing of 50 cases with a range of initial positions and velocities.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Interdependent Estimation and Guidance With Zero-Effort-Miss Enforcement
    • Authors: Prasiddha N. Dwivedi;Shivendra N. Tiwari;Abhijit Bhattacharya;Radhakant Padhi;
      Pages: 2012 - 2022
      Abstract: An interdependent estimation and guidance design approach for interceptors is presented by enforcing a stable zero-effort-miss dynamics. The output of the estimator is the demanded lateral acceleration, which serves as the guidance command. A dynamic inversion based inner-loop autopilot design facilitates extensive six degree-of-freedom simulation studies, which shows that the proposed interdependent approach gives improved performance compared to the conventional approach where estimation and guidance are done separately.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Robust Tracking Control for Tail-Sitters in Flight Mode Transitions
    • Authors: Hao Liu;Fachun Peng;Frank L. Lewis;Yan Wan;
      Pages: 2023 - 2035
      Abstract: Tail-sitters can fly as rotary-wing or fixed-wing aircraft and the transition between the two flight modes is critical. This paper develops a robust nonlinear control method to achieve the trajectory tracking control in flight mode transitions. The coordinate system does not need to be switched neither the controller structures or parameters. Theoretical analysis and simulation studies are conducted to verify the effectiveness of the developed control approach.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Globally Valid Posterior Cramér–Rao Bound for Three-Dimensional
           Bearings-Only Filtering
    • Authors: Lorenz Schmitt;Walter Fichter;
      Pages: 2036 - 2044
      Abstract: This paper addresses the problem of three-dimensional target motion analysis from bearing measurements. The established description of uncertain directional data involves azimuth and elevation angles with additive Gaussian noise. Investigation of this widely accepted representation in terms of the corresponding Fisher information matrices reveals that the underlying probability densities are only valid for small absolute elevation angles and precise measurements. Employing spherical statistics, an alternative representation is proposed that is sensible for the whole state space and arbitrarily imprecise bearing sensors. Based on this, a globally valid posterior Cramér-Rao lower bound is derived.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Accurate Direct Strapdown Direction Cosine Algorithm
    • Authors: Zihao Xu;Jian Xie;Zhaofa Zhou;Junyang Zhao;Zhiqiang Xu;
      Pages: 2045 - 2053
      Abstract: An assessment of the error inherent in a rotation vector algorithm utilized in a strapdown inertial navigation system is presented, which shows that the accuracy cannot be improved boundlessly only by increasing the number of the used samples. After reaching the upper limit for accuracy, increasing sample size would only enlarge the algorithm error rather than improve the performance of the rotation vector algorithm. After accuracy assessment, a new method to construct a strapdown attitude algorithm is originated. Unlike previous algorithms adopting a rotation vector, the new method utilizes the direction cosine matrix differential equation as its basis and discretizes this differential equation with Taylor time series, meanwhile extracting angular velocity and its derivatives by polynomial fitting. With this method, three direction cosine matrix attitude algorithms, taking 4, 5, and 6 samples, are deduced, and their performances are evaluated with coning motion and severe maneuver profile. The results show that the new algorithms based on a direction cosine matrix differential equation can effectively handle the coning error and severe maneuver error.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Detection Rate Optimization for Swerling Targets in Gaussian Noise
    • Authors: Emanuele Grossi;Marco Lops;Luca Venturino;
      Pages: 2054 - 2065
      Abstract: In this paper, we consider a pulse radar and study the tradeoff between integration time and scan rate for diverse target scattering models. At the design stage, we optimize the available degrees of freedom (namely, pulse train length and detection threshold) so as to maximize the detection rate, defined as the average number of detections from the target per unit of time, subject to a constraint on the false alarm rate, which is the average number of false alarms from the monitored area per unit of time. This objective function allows to carefully balance the contrasting needs for a large probability of detection (achievable through a large dwell time) and a short scan time. Closed-form solutions are provided for Swerling's Cases 1 and 3 target fluctuation and for the Marcum nonfluctuating model, while, for the Swerling's Cases 2 and 4, the solution is found with the aid of computer simulation. A thorough performance analysis is given to show the achievable tradeoffs among the principal system parameters under the different target models.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Enhanced Detection of Doppler-Spread Targets for FMCW Radar
    • Authors: Wei Zhang;Huiyong Li;Guohao Sun;Zishu He;
      Pages: 2066 - 2078
      Abstract: Frequency-modulated continuous waveform signals are of great interest in automotive radar, perimeter radar, and wide-area surveillance radar applications. For automotive radars and wide-area surveillance radars, which generally utilize high Doppler frequency resolution for target recognition, the important potential target such as a walking person cannot be viewed as a point-like target due to different velocities of the reflection points of a pedestrian. The echoes of such targets have extended Doppler spectrum, and they appear as horizontal lines in the range-Doppler plane, rather than a single point considered in the traditional cases. However, the existing approaches do not make full use of the Doppler-spread characteristic to enhance the detection performance of pedestrians. In this paper, we will show how this characteristic can be used to enhance the detection performance for Doppler-spread targets. The main goal of this paper is pedestrian detection in wide-surveillance radar applications and the proposed approach can also be applied in automotive radar applications. Motivated by the Hough transform, the energies of most Doppler bins corresponding to the target will be accumulated to enhance the detection performance. The questions of how many and which cells should be accumulated in practical applications are discussed in detail. The proposed approach is based on the ordered statistical-constant false alarm rate but tailored to Doppler-spread targets. The detection performance of this algorithm is derived analytically, and verified via practical wide-area surveillance radar signals.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Novel Blind Interleaver Parameter Estimation in a Noncooperative Context
    • Authors: Changryoul Choi;Dongweon Yoon;
      Pages: 2079 - 2085
      Abstract: It is well known that the distribution of the ranks of random matrices follows a specific distribution. By partitioning ranks into two possible outcomes, we can transform the estimating interleaver parameters into the counting of success events. Using this probabilistic framework, we can efficiently determine interleaver parameters in a noncooperative context.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Optimal Sensor Placement for Dilution of Precision Minimization Via
           Quadratically Constrained Fractional Programming
    • Authors: Joe J. Khalife;Zaher Zak M. Kassas;
      Pages: 2086 - 2096
      Abstract: An approach to find the global optimal solution of the dilution of precision (DOP) problem is presented. The DOP optimization problem considered assumes an environment comprising multiple randomly predeployed sensors (or navigation sources) and an additional sensor is to be introduced at the location that minimizes variations of the DOP problem (e.g., weighted geometric DOP, horizontal DOP, vertical DOP, etc.). It is shown that the DOP problem can be formulated as a quadratically constrained fractional quadratic program. An algorithm for solving this program is presented and Monte Carlo simulation results are given demonstrating convergence of the proposed approach to the global optimal solution. Additionally, Monte Carlo simulation results are presented, demonstrating the efficacy of the proposed algorithm to solving the DOP minimization problem versus using nonlinear numerical optimization solvers, which often converge to local optima. Also, the superiority of the proposed approach is demonstrated against other approaches that approximate the DOP minimization problem.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Technical Areas and Editors: AESS IEEE Aerospace & Electronic Systems
           Society
    • Pages: 2097 - 2101
      Abstract: Presents a listing of the AESS society editors by technical area.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
  • Information for Authors
    • Pages: 2102 - 2103
      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: Aug. 2019
      Issue No: Vol. 55, No. 4 (2019)
       
 
 
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