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  Subjects -> ELECTRONICS (Total: 138 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 4)
Advances in Microelectronic Engineering     Open Access   (Followers: 1)
Advances in Power Electronics     Open Access   (Followers: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 50)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 2)
Archives of Electrical Engineering     Open Access   (Followers: 8)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 8)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 14)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Biomedical Instrumentation & Technology     Full-text available via subscription   (Followers: 4)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 12)
China Communications     Full-text available via subscription   (Followers: 1)
Circuits and Systems     Open Access   (Followers: 7)
Consumer Electronics Times     Open Access   (Followers: 3)
Control Systems     Hybrid Journal   (Followers: 18)
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 2)
Electronics     Open Access   (Followers: 3)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 4)
Electronics Letters     Hybrid Journal   (Followers: 15)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 14)
EURASIP Journal on Embedded Systems     Open Access   (Followers: 8)
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (Followers: 5)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (Followers: 4)
Frequenz     Full-text available via subscription   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 19)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 7)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 3)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription  
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 9)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 19)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 10)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 6)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 13)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 11)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 7)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Power Electronics     Hybrid Journal   (Followers: 7)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 5)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 4)
IETE Technical Review     Open Access   (Followers: 1)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 1)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 3)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 1)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 10)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 4)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Computer & Electronics Research     Full-text available via subscription   (Followers: 2)
International Journal of Control     Hybrid Journal   (Followers: 9)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 3)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
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 Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 2)
International Journal of Power Electronics     Hybrid Journal   (Followers: 3)
International Journal of Power Management Electronics     Open Access  
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 1)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 2)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 7)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 11)
ISRN Electronics     Open Access   (Followers: 1)
ISRN Signal Processing     Open Access  
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 1)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Full-text available via subscription   (Followers: 1)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 2)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 1)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 1)
Journal of Electronics (China)     Hybrid Journal   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 3)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 49)
Journal of Intelligent Procedures in Electrical Technology     Open Access  
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 4)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 1)

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Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of
   [17 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1939-1404
     Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [172 journals]   [SJR: 1.232]   [H-I: 14]
  • IEEE Journal of Selected Topics in Applied Earth Observations and Remote
           Sensing Information for Authors
    • Pages: C3 - C3
      Abstract: Provides instructions and guidelines to prospective authors who wish to submit manuscripts.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • IEEE Transactions on Geoscience and Remote Sensing institutional listings
    • Pages: C4 - C4
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Front cover
    • Pages: C1 - C1
      Abstract: Presents the front cover for this issue of the publication.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • IEEE Journal of Selected Topics in Applied Earth Observations and Remote
           Sensing publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Table of contents
    • Pages: 1409 - 1411
      Abstract: Presents the table of contents for this issue of the periodical.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Foreword to Special Issue on Reflectometry using Global Navigation
           Satellite Systems and Other Signals of Opportunity (GNSS+R)
    • Authors: Garrison; J.L.;Cardellach, E.;Gleason, S.;Katzberg, S.;
      Pages: 1412 - 1415
      Abstract: The 17 papers in this special issue focus on reflectometry using global navigation satellite systems and other signals of opportunity (GNSS+R). Papers are organized around three application areas (altimetry; land applications; ocean winds and waves) and modeling.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Precision Bounds in GNSS-R Ocean Altimetry
    • Authors: Pascual; D.;Camps, A.;Martin, F.;Park, H.;Arroyo, A.A.;Onrubia, R.;
      Pages: 1416 - 1423
      Abstract: Global navigation satellite systems (GNSS) signals offer a promising opportunity to perform mesoscale altimetry with worldwide coverage using small satellites. However, unlike the signals used in classical altimeters, the GNSS signals have smaller bandwidth and lower transmitted power. This paper analyzes the achievable height precision of the Global Navigation Satellite System Reflectometry (GNSS-R) altimeters based on the Cramér–Rao bound for time-delay estimation. Precision bounds for the composite signals GPS L1 and L5 and Galileo E1, E5, and E6 in a spaceborne mission scenario are assessed, and the optimum receiver bandwidths which minimize them are obtained.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • GNSS-Based Model-Free Sea Surface Height Estimation in Unknown Sea State
    • Authors: Yu; K.;Rizos, C.;Dempster, A.G.;
      Pages: 1424 - 1435
      Abstract: Estimating sea surface height (SSH) based on Global Navigation Satellite System (GNSS) signal measurements in the presence of a rough sea surface is a challenging problem. This paper presents a model-free SSH estimation method to handle this challenging problem. The concept of power ratio is introduced that is defined as the ratio of the correlation power at the desired code phase over the peak correlation power. This desired code phase corresponds to the peak correlation power of reflected signal when the sea surface is perfectly smooth. A power-ratio-based method is presented to estimate the delay of the reflected signal relative to the direct signal, which is then used to estimate the SSH. Two cost functions are defined to estimate the desired power ratio and the SSH through minimizing the cost functions. A low-altitude airborne experiment was conducted and both direct and reflected GNSS signals were collected. The airborne experimental data were processed to generate delay waveforms (correlation power versus code delay). Applying the experimental data to the proposed method demonstrated that the error of mean SSH estimation can be of the order of decimeter in the presence of significant wave height of about 4 m. The main advantage of the proposed method is that it does not require any a priori knowledge of the sea state information or any theoretical model. Thus, the proposed method is not affected by the modeling errors or uncertainties.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Optimization and Performance Analysis of Interferometric GNSS-R
           Altimeters: Application to the PARIS IoD Mission
    • Authors: Camps; A.;Park, H.;Valencia i Domenech, E.;Pascual, D.;Martin, F.;Rius, A.;Ribo, S.;Benito, J.;Andres-Beivide, A.;Saameno, P.;Staton, G.;Martin-Neira, M.;DAddio, S.;Willemsen, P.;
      Pages: 1436 - 1451
      Abstract: Reflectometry using Global Navigation Satellite System’s signals (GNSS-R) of opportunity was originally conceived in the early 1990 s for mesoscale altimetry, and since then, many studies have shown its applicability to other remote sensing applications such as sea state determination, soil moisture, vegetation, snow monitoring, etc. In December 2012, the Phase A studies of ESA’s PAssive Reflectometry and Interferometry System In-orbit Demonstration (PARIS IoD) mission concluded. In conventional GNSS-R (cGNSS-R), the satellite navigation signals scattered over the Earth’s surface are cross-correlated with a locally generated replica of the transmitted ones shifted in frequency ( ${Deltab}{{bf f}_{bf d}}$ ), and in delay ( ${Deltab taub}$ ). However, in PARIS, a different technique called interferometric GNSS-R (iGNSS-R) is used, which allows the use of the whole signal’s bandwidth, and improve the altimetry precision, despite the large bandwidth signals’ codes being not publically available. This is achieved by using the direct signal collected by a directive antenna, instead of the locally generated replica. This study presents a methodology to optimize the configuration of a generic iGNSS-R altimeter, and evaluate its performance. The methodology presented is then particularized to a PARIS IoD-like case.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • GNSS-R Altimeter Based on Doppler Multi-looking
    • Authors: D'Addio; S.;Martin-Neira, M.;di Bisceglie, M.;Galdi, C.;Martin Alemany, F.;
      Pages: 1452 - 1460
      Abstract: Measuring ocean mesoscale variability is one of the main objectives of next generation satellite altimeters. Current radar altimeters make observations only at the nadir sub-satellite ground track, which is not sufficient to sample the ocean surface with the required spatial and temporal sampling. The GNSS-R concept has been proposed as an alternative observation system in order to overcome this limitation, since it allows performing altimetry along several points simultaneously over a very wide swath. Latest proposed GNSS-R altimeter configurations allow measuring sea height with an accuracy of few decimeters over spatial scales of 50–100 km, by means of a single-pass. This paper proposes an innovative processing and retracking concept for GNSS-R altimeters based on the acquisition of the full delay-Doppler map (DDM), which allows to acquire multiple waveforms at different Doppler frequencies, whose footprints are located outside the typical pulse-limited region. The proposed processing adapts the Synthetic Aperture Radar (SAR) delay-Doppler concept of spaceborne radar altimeters for use in a GNSS-R system. This processing yields additional multi-look with respect to conventional GNSS-R concepts and translates into an improvement of the altimetry performance estimated to be at least 25%–30%, and even higher, depending on the wanted along-track spatial resolution. The proposed processing can also provide measurements with high spatial resolution at best possible performance, and more generally, offers various possibilities for optimal trade-off between spatial-resolution and height estimation accuracy.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Simulation and Analysis of GNSS-R Composite Waveforms Using GPS and
           Galileo Signals
    • Authors: Pascual; D.;Park, H.;Camps, A.;Arroyo, A.A.;Onrubia, R.;
      Pages: 1461 - 1468
      Abstract: Nowadays, several global navigation satellite system (GNSS) services coexist at L-band and some more will be available in the near future. These new signals were originally conceived to enhance the location accuracy, but they also offer a promising opportunity for improved GNSS-reflectometry (GNSS-R) retrievals. This work gives closed form expressions for GNSS-R waveform simulation using the composite GPS L1 and L5 and Galileo E1, E5, and E6 signals as function of the receiver bandwidth. The impact of the observation geometry and sea state on the waveform shape is studied in airborne and spaceborne conditions. Finally, the altimetric height bias using the derivative method is analyzed as function of the receiver bandwidth.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Direct Signal Enhanced Semicodeless Processing of GNSS Surface-Reflected
    • Authors: Lowe; S.T.;Meehan, T.;Young, L.;
      Pages: 1469 - 1472
      Abstract: This paper presents an aircraft demonstration of direct-signal enhanced semicodeless processing of global navigation satellite systems (GNSS) signals reflected from the Earth’s surface. Comparisons are made between this new method and an interferometric approach to GNSS reflectometry. Results show that this technique produces waveforms with greater signal-to-noise compared with the interferometric approach for all GNSS signals currently in use or planned for the near future. Alternatively, the semicodeless technique can have similar performance with smaller antennas for lower hardware costs. The semicodeless approach also has the advantage that different signals along with their different surface spatial resolutions are processed separately, each signal’s coherent integration time can be optimized, and ground/aircraft experiments and tests are free of spurious signals. The signal processing demands of the semicodeless approach are shown to be proportional to the number of signal components processed when integrated with a GNSS precise orbit determination (POD) receiver.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Study of Delay Drift in GNSS-R Altimetry
    • Authors: Martin-Neira; M.;DaAddio, S.;Vitulli, R.;
      Pages: 1473 - 1480
      Abstract: Differently to the case of a conventional spaceborne nadir-looking mono-static radar altimeter, where the fly-around time of the pulses remains basically constant (assuming an almost circular orbit around an almost spherical Earth), the bistatic geometry of GNSS-R with the transmitter and the receiver embarked on different satellites imprints a significant temporal variation to the delays of the direct and reflected signals. Within a GNSS-R-based spaceborne ocean altimeter using the PARIS concept, such temporal variation in the delay has to be compensated for with the objective to finely adjust the delay of the direct signal to permanently match with that of the reflected signal according to some a priori model of the geometry. The impact of the residual delay drift on the accuracy and the precision of the range observations is assessed here.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Analysis of Spaceborne GNSS-R Delay-Doppler Tracking
    • Authors: Park; H.;Pascual, D.;Camps, A.;Martin, F.;Alonso-Arroyo, A.;Carreno-Luengo, H.;
      Pages: 1481 - 1492
      Abstract: For spaceborne Global Navigation Satellite System-Reflectometry (GNSS-R), the delay and Doppler frequency conditions dynamically change, so the compensation of the delay and Doppler errors using tracking is important to the altimetric and scatterometric performances. This work presents the characteristics of the delay and the Doppler frequency in spaceborne GNSS-R, such as the range of them, the Doppler spreading width, and the change rate. They are important considerations for design of the delay and Doppler tracking strategy. The characteristics of delay-Doppler conditions of spaceborne GNSS-R are presented with additional considerations for tracking design. The tracking methods are discussed, and the error impacts are visually demonstrated by using the spaceborne measured data from United Kingdom’s Disaster Monitoring Constellation (UK-DMC) satellite.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Experimental Evaluation of GNSS-Reflectometry Altimetric Precision Using
           the P(Y) and C/A Signals
    • Authors: Carreno-Luengo; H.;Camps, A.;Ramos-Perez, I.;Rius, A.;
      Pages: 1493 - 1500
      Abstract: This work describes a novel dual-band Global Navigation Satellite Systems Reflectometer (GNSS-R) that uses the P(Y) and C/A signals scattered over the sea surface to perform highly precise altimetric measurements. The results derived from two different ground-based field experiments over a dam and over the sea under different surface’s roughness conditions are presented. The analysis of the altimetric performance shows that the results obtained using the P(Y) code improve by a factor between 1.4 and 2.4 as compared to the results obtained using the C/A code, respectively, for high and mid-low satellite’s elevation angles.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Normalized Microwave Reflection Index: A Vegetation Measurement Derived
           From GPS Networks
    • Authors: Larson; K.M.;Small, E.E.;
      Pages: 1501 - 1511
      Abstract: Measurements of vegetation state are required both for modeling and satellite validation. Reflected GPS signals recorded by the Plate Boundary Observatory network provide a source of new information about vegetation state in the western United States and Alaska. The GPS ground stations were installed between 2005 and 2008 to measure plate boundary deformation. They operate continuously and transmit their data to a public facility at least once per day. However, they also act as bi-static radars by recording the interference between a direct GPS signal (transmitted at 1.5 GHz) and a reflected GPS signal. The frequency of this interference pattern primarily depends on the vertical distance between the antenna and the ground reflector. As an L-band sensor, the amplitude of the interference pattern depends on vegetation water content. A daily vegetation metric that depends on reflection amplitudes, Normalized Microwave Reflection Index (NMRI), is defined. A method for removing outliers caused by snow and rain is described. The footprint of NMRI depends on the antenna height and local terrain. The minimum footprint is ${bf 1000}nbsp{bf m}^{bf 2}$ . A database of more than 300 station NMRI time series has been compiled; these data span the period from 2007 to 2012. Comparisons between NMRI and in situ sampling of vegetation state are the subject of a companion paper.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Normalized Microwave Reflection Index: Validation of Vegetation Water
           Content Estimates From Montana Grasslands
    • Authors: Small; E.E.;Larson, K.M.;Smith, W.K.;
      Pages: 1512 - 1521
      Abstract: The Normalized Microwave Reflection Index (NMRI) measures the intensity of GPS reflections, which is affected by vegetation within $sim{bf 100}nbsphbox{bf m}$ of GPS antennas. In a companion paper, the theoretical basis for NMRI and how it is derived from data archived at geodetic GPS installations are described. NMRI is calculated by normalizing the standard GPS metric ${bf MP}_{bf 1}{bf rms}$ on a site-by-site basis to minimize terrain effects. Here, we validate NMRI as a metric for estimating vegetation water content (VWC) and evaluate the normalization procedure. In situ measurements of plant height, biomass, and VWC were taken on a biweekly basis during 2012 at four grassland sites in Montana. These measurements were compared to time series of ${bf MP}_{bf 1}{bf rms}$ , NMRI, and Normalized Difference Vegetation Index (NDVI) from each site. At each site, a significant linear relationship exists between ${bf MP}_{bf 1}{bf rms}$ and VWC. However, this relationship is not consistent across sites. Once normalized, a linear relationship exists between NMRI and VWC ( ${bf r}^{bf 2} = {bf 0.71}$ ) that is consistent across the four sites. This suggests that VWC could be predicted from NMRI at sites without in situ observations, as long as vegetation and climate are similar. There is no clear relationship between NMRI and either vegetation height or biomass. The importance of normalization is shown using data from eight additional sites. After normalization, a strong positive correlation is apparent between NMRI and NDVI across all grassland GPS sites in Mo- tana.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Airborne GNSS-R Polarimetric Measurements for Soil Moisture and
           Above-Ground Biomass Estimation
    • Authors: Egido; A.;Paloscia, S.;Motte, E.;Guerriero, L.;Pierdicca, N.;Caparrini, M.;Santi, E.;Fontanelli, G.;Floury, N.;
      Pages: 1522 - 1532
      Abstract: Soil moisture content (SMC) and above-ground biomass (AGB) are key parameters for the understanding of both the hydrological and carbon cycles. From an economical perspective, both SMC and AGB play a significant role in the agricultural sector, one of the most relevant markets worldwide. This paper assesses the sensitivity of Global Navigation Satellite System (GNSS) reflected signals to soil moisture and vegetation biomass from an experimental point of view. For that, three scientific flights were performed in order to acquire GNSS reflectometry (GNSS-R) polarimetric observations over a wide range of terrain conditions. The GNSS-R data were used to obtain the right–left and right–right reflectivity components, which were then georeferenced according to the transmitting GNSS satellite and receiver positions. It was determined that for low-altitude GNSS-R airborne platforms, the reflectivity polarization ratio provides a highly reliable observable for SMC due to its high stability with respect to surface roughness. A correlation coefficient ${bf r}^{bf 2}$ of 0.93 and a sensitivity of 0.2 dB/SMC (%) were obtained for moderately vegetated fields with a surface roughness standard deviation below 3 cm. Similarly, the copolarized reflection coefficient shows a stable sensitivity to forest AGB with ${bf r}^{bf 2}$ equal to 0.9 with a stable sensitivity of 1.5 dB/(100 t/ha) up to AGB values not detectable by other remote sensing systems.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Dual-Polarization GNSS-R Interference Pattern Technique for Soil Moisture
    • Authors: Alonso Arroyo; A.;Camps, A.;Aguasca, A.;Forte, G.F.;Monerris, A.;Rudiger, C.;Walker, J.P.;Park, H.;Pascual, D.;Onrubia, R.;
      Pages: 1533 - 1544
      Abstract: The interference pattern technique (IPT) consists of the coherent addition of the direct and reflected global navigation satellite systems (GNSS) signals in the receiving antenna. The detected power oscillates (fading), and the amplitude of these oscillations is very sensitive to the soil reflection coefficient at the specular reflection point. Therefore, variations of the reflection coefficient can be mapped, and thus dielectric constant variations, from which soil moisture can be retrieved. This work extends the use of the IPT technique from vertical polarization (V-Pol) to horizontal polarization (H-Pol). Moreover, the IPT equations are reformulated to facilitate the combination of dual-polarization retrievals. Simulations of the interference patterns at V- and H-Pol are presented for different soil moisture conditions. An upgrade of the SMIGOL GNSS-R instrument for dual-polarization observations is presented. This instrument was deployed in a flat, dry grassland in Yanco, Australia, in order to validate the proposed concepts. Finally, a comparison between the data retrieved from the SMIGOL instrument and the ground-truth soil moisture data is presented showing a good agreement between them and rainfall information.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Modeling and Analysis of GNSS-R Waveforms Sample-to-Sample Correlation
    • Authors: Martin; F.;DAddio, S.;Camps, A.;Martin-Neira, M.;
      Pages: 1545 - 1559
      Abstract: The exploitation of global navigation satellite systems Earth-reflected signals to perform ocean mesoscale altimetry from space has been originally proposed at the beginning of the 1990s. This technique is generally defined as “GNSS-R.” Since then, the versatility and availability of the GNSS-R has been the subject of studies targeting many other earth remote sensing applications, for both ocean and land. GNSS-R observables (called GNSS-R “waveforms”) are typically obtained by performing a complex cross-correlation of the received GNSS reflected signals with a locally generated replica of one of the open access GNSS signals, evaluated over a pre-defined set of delays of the local replica. The knowledge of the statistical properties of GNSS-R waveforms is of fundamental importance in order to define the retrieval algorithms to estimate the geophysical parameters and in order to optimize the accuracy of these estimations. The statistical properties of interest are mainly: 1) the correlation between realizations of GNSS-R waveforms generated at different time instants (generally defined as slow-time correlation) and 2) the correlation between the different delay samples of a given GNSS-R waveform (generally defined as fast-time or sample-to-sample correlation). The modeling and analysis of the slow-time statistical properties has been the subject of previous works. On the other hand, this paper presents for the first time a detailed analytical model describing the sample-to-sample statistics of GNSS-R waveforms. The model has been validated with real measurements of global positioning systems (GPSs) reflected signals collected by UK-DMC receiver, showing excellent agreement with the observations from space. The model is generic and can be easily extended to GNSS-R waveforms from other systems. For altimetry applications, the knowledge of waveform statistics allows to assess the dependence of altimetry performance on crit- cal system/instrument and retrieval parameters such as the sampling frequency, the receiver bandwidth or signal-to-noise-ratio (SNR). This paper also presents an analysis of the impact of these parameters on instrument performance, the conclusions of which are general and constitute an important basis for optimization of future GNSS-R instruments.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Cross-Correlation Waveform Analysis for Conventional and Interferometric
           GNSS-R Approaches
    • Authors: Martin; F.;Camps, A.;Park, H.;DaAddio, S.;Martin-Neira, M.;Pascual, D.;
      Pages: 1560 - 1572
      Abstract: Reflectometry using Global Navigation Satellite System (GNSS-R) signals has become an attractive tool for Earth remote sensing. Back to 1993, it was proposed as an alternative to the conventional spaceborne ocean altimetry to estimate the sea surface height over a large field-of-view. After Doppler compensation, the cross-correlation of the received scattered signal with either a locally generated replica [conventional GNSS-R (cGNSS-R)] or either the direct signal (interferometric GNSS-R (iGNSS-R)] is called the waveform. This paper provides a critical review of the cross-correlation waveform model, addressing issues such as the correlation characteristics, the bandwidth, the observation geometry, and the thermal and speckle noises. It provides a comprehensive and systematic overview of the impact of all these effects on the GNSS-R observables, which is important to properly define future GNSS-R instrument and mission concepts.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Reconstruction of the Normalized Radar Cross Section Field From GNSS-R
           Delay-Doppler Map
    • Authors: Schiavulli; D.;Nunziata, F.;Pugliano, G.;Migliaccio, M.;
      Pages: 1573 - 1583
      Abstract: An effective approach to reconstruct the normalized radar cross section (NRCS) image from Global Navigation Satellite System-Reflectometry (GNSS-R) Delay-Doppler Map (DDM) is proposed. It is physically based on the truncated singular value decomposition (TSVD), properly extended to the 2-D case (2-D TSVD). The proposed approach is tested against simulated noisy DDMs, where both the additive and multiplicative noise are accounted for. The latter, generally known as speckle, is modeled using a Rice distribution. Experimental results show that the 2-D TSVD can be successfully exploited to reconstruct the NRCS field from DDM noisy measurements. Moreover, an analysis on the spatial resolution which characterizes the reconstructed domain is undertaken: it shows that generally a nonuniform spatial resolution is achieved while an area of the observed scene presents a almost uniform resolution that can be useful for remote sensing purposes.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Application of the ICF Coherence Time Method for Ocean Remote Sensing
           Using Digital Communication Satellite Signals
    • Authors: Shah; R.;Garrison, J.L.;
      Pages: 1584 - 1591
      Abstract: This paper applies an ocean remote sensing method, first developed for reflected Global Navigation Satellite System (GNSS-R) signals, to reflected digital communication satellite signals. The fundamental observation is the time series of the Interferometric Complex Field (ICF) of the reflected signal. A relationship is derived between the coherence time of the ICF time series and the significant wave height (SWH) and mean wave period (MWP) of the ocean. Direct and reflected signals from the S-band satellite transmissions providing the commercial XM radio service were recorded at Platform Harvest over a 65-day period. In situ measurements from a nearby buoy were used to calibrate this measurement by determining coefficients of a semi-empirical model. SWH retrievals using this model on 1 min of reflected signal observations were found to have a standard deviation of 0.38 m over the range from 1 to 4.5 m. An error analysis was done to show that the primary contribution to this error was uncertainty in the relationship between MWP and SWH, and to quantify the retrieval error from different forward models.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Ray-Tracing of GNSS Signal Through the Atmosphere Powered by CUDA, HMPP
           and GPUs Technologies
    • Authors: Gegout; P.;Oberle, P.;Desjardins, C.;Moyard, J.;Brunet, P.-M.;
      Pages: 1592 - 1602
      Abstract: The ray-tracing of signals emitted by the Global Navigation Satellite Systems (GNSS) is implemented on Graphics Processing Units (GPU) by two parallel programming techniques: the “Compute Unified Device Architecture” (CUDA) C-language and the directives for “Hybrid Multicore Parallel Programming” (HMPP) developed by CAPS Entreprise. The signal propagation is obtained by the numerical integration of the differential system derived from the eikonal equation by the Runge-Kutta method. The computation of atmospheric delays on GPU has to preserve the millimeter accuracy using the double precision arithmetic. Four versions describe how the ray-tracing of 8,100 rays was optimized for the Fermi architecture. As referring to a single-core single-threaded CPU version, accelerations ranging from 20 to 50 times are progressively obtained when the software enhancements gradually harness the hardware capabilities. The versions HMPP and CUDA provide exactly the same accelerations. HMPP further provides an easy implementation for multiple kind of GPU cards. A speed-up of 75 times versus the CPU version is finally reached when the ray-tracing algorithm is applied to 130,000 rays.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Adaptive Retracking of Jason-1, 2 Satellite Altimetry Data for the Volga
           River Reservoirs
    • Authors: Troitskaya; Y.;Rybushkina, G.;Soustova, I.;Lebedev, S.;
      Pages: 1603 - 1608
      Abstract: The problem of minimization of errors in water level retrieval for the Volga reservoirs from altimetry measurements can be resolved by retracking Jason-1, 2 satellite altimetry data. For justification of the optimal retracking algorithm average impulse response of a statistically inhomogeneous surface was calculated theoretically for a model of the terrain in the neighbourhood of the reservoirs. The modeled waveforms are in good agreement with Jason-1, 2 waveforms for the same area. Comparison of the data with in situ measurements shows that retracking significantly improves measurement of the water level. General principles of the retracking algorithms for complex areas (land, coastal zone, inland waters, etc.) based on calculations of the waveforms taking into account statistical inhomogeneity of the reflecting surface adapted to a certain geographic region, are discussed.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • A Landsat-5 Atmospheric Correction Based on MODIS Atmosphere Products and
           6S Model
    • Authors: Hu; Y.;Liu, L.;Liu, L.;Peng, D.;Jiao, Q.;Zhang, H.;
      Pages: 1609 - 1615
      Abstract: The Landsat satellite series represents the longest record of global-scale medium spatial resolution earth observations, and the utility of Landsat data for long-term and/or large-area monitoring depends on accurate and quantitative atmospheric correction to produce a consistently corrected surface reflectance (SR) dataset. In this study, we developed a rapid, automated atmospheric correction procedure based on Moderate Resolution Imaging Spectrometer (MODIS) atmospheric characterization products and the 6S (Second Simulation of a Satellite Signal in the Solar Spectrum) radiative transfer code for Landsat-5 Thematic Mapper (TM) imagery. Three MODIS atmosphere products at the resolution of 0.05 ${^circ}$ , MOD04, MOD05, and MOD07 were used as input to the 6S radiative transfer model in order to compute the parameters required for atmospheric correction, which were then used to correct TM imagery per-pixel automatically. This method was tested using five multi-date Landsat TM images in Beijing, China, and the atmospheric correction precision was assessed using ground-measured reflectance. The result showed that the SR retrieved from Landsat TM is consistent with the ground measurements, with a mean ${R^2}$ of 0.773 and a mean root mean square error value of 0.045.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • A Robust Algorithm to Determine Diffuse Attenuation Coefficient of
           Downwelling Irradiance From Satellite Data in Coastal Oceanic Waters
    • Authors: Tiwari; S.P.;Shanmugam, P.;
      Pages: 1616 - 1622
      Abstract: Despite the importance of diffuse attenuation coefficient of downwelling irradiance (K $ _{rm d}$ ) to physical, chemical and biological processes in the euphotic zone, accurate determination of this apparent optical property from satellite ocean color data for coastal oceanic waters is still challenging with most of the existing algorithms. This paper presents a simple and robust algorithm developed using the relationship (R² = 0.995) of the ratio of remote sensing reflectances at 490 and 670 nm to the K $ _{rm d}$ at a wavelength of 490 nm derived from a large number of radiometric profiles from various regional waters. When tested with three independent data sets from relatively clear and turbid waters, accuracy of K $ _{rm d}$ (490) prediction by the present algorithm is statistically good compared to that of the existing algorithms. The effectiveness of the present algorithm is also tested on MODIS-Aqua images from complex waters around India. It is found that the present algorithm makes better retrievals of K $_{rm d}$ (490) capturing the spatial characteristics of bloom and turbid water features. These results suggest that the present algorithm has the potential to provide more accurate K $_{rm d}$ (490) from satellite ocean color data for coastal oceanic waters.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Assimilation of MODIS Chlorophyll-a Data Into a Coupled
           Hydrodynamic-Biological Model of Taihu Lake
    • Authors: Qi; L.;Ma, R.;Hu, W.;Loiselle, S.A.;
      Pages: 1623 - 1631
      Abstract: MODIS chlorophyll-a concentration (Chla) data were assimilated into a coupled hydrodynamic-biological model using an Optimal Interpolation method. Simulations were conducted using MODIS data covering Taihu Lake in May 2009, when algal blooms typically begin to occur. The results of the assimilation approach showed improvements in the estimation of Chla distributions in spatial coherency and temporal continuity. Bias of assimilation (model run after assimilation) was 5.1%, with a RMSE of 49.7%. In comparison, the free run (model run without assimilation) had a bias of –34.9% and RMSE of 176.5%. In situ data used for comparison showed reduced RMSE and the Bias for assimilation. Two sensitivity experiments were used to determine the suitable correlation length scale with respect to observation data accuracy. The result showed that 500m is the optimum scale to construct the background error covariance matrix. The sensitivity experiment of observational data accuracy also showed that more accurate observation data allowed for better assimilation results.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Empirical Relationships for Monitoring Water Quality of Lakes and
           Reservoirs Through Multispectral Images
    • Authors: Dona; C.;Sanchez, J.M.;Caselles, V.;Dominguez, J.A.;Camacho, A.;
      Pages: 1632 - 1641
      Abstract: Remote sensing techniques can be used to estimate water quality variables such as chlorophyll ${mbi a}$ , total suspended particles, and water transparency. This paper describes empirical algorithms for the estimation of these variables using Landsat Thematic Mapper (TM) data. Ground data were taken from several Spanish lakes covering a variety of trophic statuses, ranging from oligotrophic to hypereutrophic. The studied lakes were the Albufera de Valencia and lakes and ponds of the Southeast Regional Park in Madrid. Empirical equations were obtained to estimate chlorophyll ${mbi a}$ from the ratio in reflectance values between bands 2 and 4 of TM ( $bf{ R^2 , {mmb =}, 0.66}$ , ${bf p} {bf lt} {bf 0.001}$ ), transparency [Secchi disk (SD)] from reflectance in band 2 ( $bf{ R}^2, {mmb =}, 0.80$ , $bf{ p} {bf lt} {bf 0.001}$ ), and total suspended particles from reflectance in band 4 ( $bf{ R}^2, {mmb =}, 0.92$ , $bf{ p} {bf lt} {bf 0.001}$ ). The spectral equivalence between TM and the recent satellite Deimos-1 was also tested. By applying the proposed algorithms to this new sensor, the temporal resolution is improved by up to 3 days, which increases spatial resolution to 22 m. The algorithms were validated using three Deimos-1 scenes of the Albufera de Valencia together with ground measurements. Results of this validation showed root-mean-square errors (RMSEs) of $bf- 40nbsphbox{mg}cdothbox{m}^{mmb-3}$ for Chl- $mbi a$ (data range: $bf 32 mmb {-} 238nbsphbox{mg}cdothbox{m}^{-3}$ ), $bf 10nbsphbox{mg}cdothbox{L}^{mmb -1}$ for total suspended solid (TSS) (data range: $bf 25{mmb -}89nbsphbox{mg}cdothbox{L}^{mmb -1}$ ), and 0.10 m for SD (data range: 0.17–0.40 m). In any case, these results show the potential of Deimos-1 as a substitute of TM in water quality monitoring in small/medium water bodies, providing continuity to three decades of TM imagery.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Subsidence Monitoring of Tianjin Suburbs by TerraSAR-X Persistent
           Scatterers Interferometry
    • Authors: Luo; Q.;Perissin, D.;Lin, H.;Zhang, Y.;Wang, W.;
      Pages: 1642 - 1650
      Abstract: This paper illustrates the first wide area study over Tianjin suburbs of China using persistent scatterers interferometry (PSI) technique for ground subsidence monitoring via high-resolution TerraSAR-X (TSX) SAR data. The deformation rate and the displacement history of the subsiding areas from April 29, 2009 to November 11, 2011 have been reconstructed. The results demonstrate the capability of applying PSI technique to high-resolution SAR time series imageries for monitoring of the subsidence of multiple towns and large-scale man-made linear features (LMLFs) such as railways, highways, and power lines. The comprehensive uncertainties were analyzed between PSI results and ground-leveling data whose densities are very different in both spatial and temporal domains. The overall results show a good agreement with each other. We also found that the underground water extraction and lithological character are the two important potential explanations to the location and shape of the subsiding centers.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • ${rm+CO}_2$++Gas&rft.title=Selected+Topics+in+Applied+Earth+Observations+and+Remote+Sensing,+IEEE+Journal+of&rft.issn=1939-1404&;Shaw,++J.A.;Lawrence,++R.L.;Nugent,++P.W.;Hogan,++J.A.;Dobeck,++L.M.;Spangler,++L.H.;">Comparison of Long-Wave Infrared Imaging and Visible/Near-Infrared Imaging
           of Vegetation for Detecting Leaking        Notation="TeX">${rm CO}_2$ Gas
    • Authors: Johnson; J.E.;Shaw, J.A.;Lawrence, R.L.;Nugent, P.W.;Hogan, J.A.;Dobeck, L.M.;Spangler, L.H.;
      Pages: 1651 - 1657
      Abstract: Recent research demonstrated that ${mmb CO}_{mmb 2}$ gas leaking from underground can be identified by observing increased stress in overlying vegetation using spectral imaging. This has been accomplished with both visible/near-infrared (Vis/NIR) sunlight reflection and long-wave infrared (LWIR) thermal emission. During a 4-week period in summer 2011, a controlled ${mmb CO}_{mmb 2}$ release experiment was conducted in Bozeman, Montana, as part of a study of methods for monitoring carbon sequestration facilities. As part of this experiment, reflective and emissive imagers were deployed together to enable a comparison of these two types of imaging systems for vegetation-based ${mmb CO}_{mmb 2}$ leak detection. A linear regression was performed using time as the response variable with red and NIR reflectances, Normalized Difference Vegetation Index (NDVI), and LWIR brightness temperature as predictors. The regression study showed that the reflectance and LWIR brightness temperature data together explained the most variability in the data (96%), equal to the performance of the Vis/NIR reflectance data alone, followed by NDVI alone (90%), and LWIR data alone (44%). Therefore, the two types of imagers contributed in a synergistic fashion, while either method alone was capable of gas detection with increased statistical variability.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Viability Statistics of GLAS/ICESat Data Acquired Over Tropical Forests
    • Authors: Baghdadi; N.N.;El Hajj, M.;Bailly, J.S.;Fabre, F.;
      Pages: 1658 - 1664
      Abstract: The Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud, and land Elevation satellite (ICESat) provides a useful dataset for characterizing tropical forests. However, some GLAS data are not viable for science processing. This work aims at quantifying GLAS data viability at a global scale over all tropical forests and determining the parameters that affect this viability. The percentage of nonviable data was analyzed according to several parameters: latitude, longitude, transmitted energy, GLAS mission, local hour of acquisition, and cloud parameters. Results show that only 79.9% of all GLAS data acquired between 2003 and 2009 is viable for tropical forests characterization. By applying additional filters used by scientists in the GLAS data processing for forestry applications, only 32.8% of GLAS data acquired over tropical forests becomes exploitable. The percentage of nonviable data seems higher over the equator, for low transmitted energy, for acquisition time between 10 and 13 local hour, for high cloud humidity, and for some geographical areas. Finally, in a multifactor approach, the Random Forest regression method demonstrated that the parameters that most significantly influence the returned LiDAR signal are transmitted energy and cloud presence index.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Automatic Measurement of Polynya Area by Anisotropic Filtering and Markov
           Random Fields
    • Authors: Moctezuma Flores; M.;Parmiggiani, F.;Lopez Lopez, L.;
      Pages: 1665 - 1674
      Abstract: This paper presents a processing scheme for the automatic measurement of polynya area as observed by Cosmo-SkyMed (CSK) SAR-X images. The processing scheme, based on anisotropic filtering and on Markov Random Fields, was tested with two CSK SAR-X images captured during the polynya events occurred on September 10 and 26, 2009, at Terra Nova Bay, Antarctica. The good correspondence between the polynya extent, as obtained by the automatic method and clearly identified by visual inspection, confirms the soundness of the proposed processing scheme.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Spatial–Temporal Analyses of Surface Coal Mining Dominated Land
           Degradation in Holingol, Inner Mongolia
    • Authors: Qian; T.;Bagan, H.;Kinoshita, T.;Yamagata, Y.;
      Pages: 1675 - 1687
      Abstract: Surface coal mining and urbanization, as well as crop-based agriculture, have resulted in accelerated degradation and desertification of grasslands in the Holingol region, Inner Mongolia Autonomous Region, over the last three decades. The purpose of this study was to investigate the spatial–temporal changes of land cover due to the surface coal-mining activities in the Holingol region from 1978 to 2011. In this study, we used the subspace method to apply land-cover classification schemes to Landsat archival images from 1978, 1988, 1999, and 2011. We then used the grid square method to investigate spatial–temporal land-cover changes during the period of 1978–2011. The results show that both surface coal mining and urban areas have increased dramatically. This expansion was accompanied by considerable loss of grassland and wetland. Grid-cell-based spatial–temporal analysis showed that urban/bare expansion had a strong negative correlation with grassland change ( $-{bf 0.67}$ ), coal-mining area expansion had a negative correlation with grassland change ( $-{bf 0.29}$ ), and coal-mining area expansion was positively correlated with urban/bare expansion (0.21). Furthermore, the correlation coefficients of land-cover categories for three time intervals between 1978 and 2011 (1978–1988, 1988–1999, and 1999–2011) showed that there was almost no correlation between grassland and coal-mining area in 1978–1988 and 1988–1999, but the correlation coefficient became negative ( $-{bf 0.21}$ ) in 1999–2011.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Automatic Line Segment Registration Using Gaussian Mixture Model and
           Expectation-Maximization Algorithm
    • Authors: Long; T.;Jiao, W.;He, G.;Wang, W.;
      Pages: 1688 - 1699
      Abstract: Line segment registration (LSR) for image pairs is a challenging task but plays an important role in remote sensing and photogrammetry. This paper proposes a line segment registration method using Gaussian Mixture Models (GMMs) and Expectation-Maximization (EM) algorithm. Comparing to the conventional registration methods which consider the local appearance of points or line segments, the proposed method of LSR uses only the spatial relations between the line segments detected from an image pair, and it does not require the corresponding line segments sharing the same start points and end points. Although the proposed method is not confined to the transformation model between the image pair, the affine model, which is a simple and fast registration model and widely used in remote sensing, is taken to verify the proposed method. Various images including aerial images, satellite images and GIS data are used to test the algorithm, and test results show that the method is robust to different conditions, including rotation, noise and illumination. The results of the proposed method are compared with those of other line segment matching methods, and it is shown that the proposed method is superior in matching precision and performs better in less-texture or no-texture case.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • A Modified Phase Shift Migration Algorithm Applied to 2D and 3D
           Through-the-Wall Imaging
    • Authors: Zhang; P.;Zhang, X.;
      Pages: 1700 - 1708
      Abstract: When the PSM (phase-shift migration) is used in TWI (Through-the-wall imaging), the image is defocused due to the presence of the wall. In this paper, a new algorithm based on the PSM method is proposed to tackles this problem. In order to compensate the effects of the wall, the conjugated wall transmissivity is integrated into the imaging formula, which is derived from the spectrum Green's function for multilayered medium. The two merits of our proposed method are: 1) the wall compensation is manipulated in the spatial frequency domain, which avoids a time-consuming calculation of the incidences angles; 2) the image is reconstructed by the fast Fourier transform (FFT) efficiently. The proposed method is implemented for 2D and 3D applications on synthetic-generated data and applied to the 2D experimental data collected at a test site. The results demonstrate that our method generates high quality focused images and achieves target geometrical identification within a very short time. Therefore, the new method provides a promising real-time solution with high fidelity in TWI.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Phase-Ramp Reduction in Interseismic Interferograms From Pixel-Offsets
    • Authors: Wang; T.;Jonsson, S.;
      Pages: 1709 - 1718
      Abstract: Interferometric synthetic aperture radar (InSAR) is increasingly used to measure interseismic deformation. Inaccurate satellite–orbit information, expressed as phase ramps across interseismic interferograms, is believed to be one of the main sources of error in such measurements. However, many interferograms exhibit higher phase gradients than expected from the reported orbital accuracy, suggesting that there are other error sources. Here, we show that interferogram phase ramps are in part caused by uncorrected satellite timing-parameter errors. We propose a two-step approach to reduce the phase ramps using pixel-offsets estimated between SAR amplitude images. The first step involves using a digital elevation model (DEM) to estimate absolute timing-parameter errors for the reference image of the SAR dataset and the second step updates the timing parameters of the master image for each interferogram. We demonstrate a clear ramp reduction on interseismic interferograms covering the North Anatolian Fault in eastern Turkey. The resulting interferograms show clear signs of interseismic deformation even before stacking.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Hybrid Technique Using Singular Value Decomposition (SVD) and Support
           Vector Machine (SVM) Approach for Earthquake Prediction
    • Authors: Astuti; W.;Akmeliawati, R.;Sediono, W.;Salami, M.J.E.;
      Pages: 1719 - 1728
      Abstract: Most of the existing earthquake (EQ) prediction techniques involve a combination of signal processing and geophysics techniques which are relatively complex in computation for analysis of the Earth’s electric field data. This paper proposes a relatively simpler and faster method that involves only signal processing procedures. The prediction of the EQ occurrence estimation using a combination of singular value decomposition (SVD)-based technique for feature extraction and support vector machine (SVM) classifier is presented in this paper. Using the proposed method, the Earth’s electric field signal is transformed into a new domain using SVD-based approach. In this approach, the time domain signal is projected on the left eigenvectors of impulse response matrix of the linear prediction coefficient (LPC) filter. Several features have been extracted from the transformed signal. These features are used as input for the SVM classifier in order to predict the location of the forthcoming EQ. Once the location is determined, a similar approach is used to estimate its magnitude. Finally, the time estimation of the forthcoming EQ is estimated based on the statistical observation. The occurred EQs during 2008 in Greece are used to train the classifiers, whereas those occurred from 2003 to 2010 in the same region are used to evaluate the performance of the proposed system. In predicting the location of the future EQs, the proposed system could achieve 77% accuracy. As for the magnitude prediction, the proposed system provides an accuracy of 66.67%. Moreover, the predicted time for the EQ with magnitude greater than $bf {Ms} = 5$ is 2 days ahead, whereas for magnitude greater than $bf {Ms} = 6$ is up to 7 days ahead.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Applicability of SAR to Marine Debris Surveillance After the Great East
           Japan Earthquake
    • Authors: Arii; M.;Koiwa, M.;Aoki, Y.;
      Pages: 1729 - 1744
      Abstract: After the Great East Japan earthquake on March 11, 2011, a huge amount of marine debris of more than 1.5 million tons was generated. It damaged the global marine environment, and reached the west coast of the United States around October 2012. As marine debris spreads with time, the chance of our observation was limited. To achieve an efficient time series analysis, we have to utilize complete advantage of the existing synthetic aperture radar (SAR) data with its wide range of observation conditions. In this study, an applicability of SAR to the tsunami disaster after the Great East Japan earthquake is discussed by estimating several key parameters such as total amount of marine debris and their vector velocities from SAR images obtained just after the earthquake under various observation conditions. Based on the analyses, we also discuss optimum marine debris monitoring by SAR to minimize the damage from tsunami disasters in future.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • The HelioClim-1 Database of Daily Solar Radiation at Earth Surface: An
           Example of the Benefits of GEOSS Data-CORE
    • Authors: Lefevre; M.;Blanc, P.;Espinar, B.;Gschwind, B.;Menard, L.;Ranchin, T.;Wald, L.;Saboret, L.;Thomas, C.;Wey, E.;
      Pages: 1745 - 1753
      Abstract: The HelioClim-1 database contains daily values of the solar radiation reaching the ground. This GEOSS (Global Earth Observation System of Systems) Data Collection of Open Resources for Everyone (Data-CORE) covers Europe, Africa and the Atlantic Ocean, from 1985 to 2005. It is freely accessible at no cost through the SoDa Service ( Several assessments of the HelioClim-1 data against measurements made in meteorological networks reveal that the HelioClim-1 database offers a reliable and accurate knowledge of the solar radiation and its daily, seasonal and annual variations over recent years. The HelioClim-1 data may help in qualifying in situ measurements and may supplement them, thus offering 21 years of accurate daily means of surface solar irradiance. Several published works benefited from openness, availability and accuracy of the HelioClim-1 database in various domains: oceanography, climate, energy production, life cycle analysis, agriculture, forestry, architecture, health and air quality. This demonstration of the benefit of the HelioClim-1 database draws attention to resources open to everyone such as those labeled GEOSS Data-CORE.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Clustering of Cyclostationary Signals with Applications to Climate Station
           Sitings, Eliminations, and Merges
    • Authors: Schkoda; R.F.;Lund, R.B.;Wagner, J.R.;
      Pages: 1754 - 1762
      Abstract: This paper considers methods to classify and discriminate the multidimensional cyclostationary climatological time series. The methods take into account both the seasonal mean cycles and random behavior in the series, simultaneously considering means and all component-by-component autocovariances. This improves classical Hotelling ${T^2}$ statistics that classify through mean changes only, and constant-mean speech methods that classify exclusively through sample autocovariance differences. Here, two series are compared by assuming that both follow the same time series model; from this, a test statistic representing a distance between the two series is developed from linear prediction theory. This construction generates a level- $alpha $ test statistic for Gaussian data that can be used to assess how different the two series are. The derived distances can be used in a clustering algorithm, e.g., to group series with similar behavior. Such information is useful to eliminate or merge the climate stations whose data are redundant to another station or to optimally locate a collection of stations. The techniques are first tested on simulated series with known structures, and then applied to 11 two-dimensional series in the National Oceanic and Atmospheric Administration’s data buoy catalog. Natural clusters emerge which are geographically realistic. Specifically, the methods were able to perfectly group stations in the Gulf of Mexico, the Carolina Coast, the Pacific Ocean, and offshore New England.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Performance Monitoring of the S-NPP Ozone Mapping and Profiler
           Suite’s Sensor Data Records
    • Authors: Pan; C.;Flynn, L.;Buss, R.;Wu, X.;Yu, W.;Grotenhuis, M.;
      Pages: 1763 - 1770
      Abstract: Launched on October 28, 2011, the S-NPP satellite carried an ozone mapping and profiler suite (OMPS) of sensors. OMPS opened its aperture door on January 26, 2012 to begin its Earth observation mission. After an early orbit checkout of the sensors for a couple of months and an intensive evaluation of the sensor data for several more months, an initial on-orbit calibration for OMPS was established using data acquired during these periods. To date in 2013, this sensor system calibration has been applied to produce OMPS nadir sensor data records (SDRs) and the resulting ozone environment data records (EDRs). This paper provides an evaluation of the combined performance of the orbital OMPS nadir sensors coupled with the ground data processing system for the current SDR’s provisional status, and offers lessons learned during the first 1.5 years of operation. Examples of the sensors’ short-term and limited long-term responses are provided, including cross-comparisons of OMPS EDRs with concurrent solar backscatter ultraviolet instrument (SBUV2) data from other NOAA orbital sensors, to illustrate the on-orbit stability of the data products despite some secular changes to the calibration and sensor.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Multiresolution Image Fusion: Use of Compressive Sensing and Graph Cuts
    • Authors: Harikumar; V.;Gajjar, P.P.;Joshi, M.V.;Raval, M.S.;
      Pages: 1771 - 1780
      Abstract: In this paper, we propose a new approach for multiresolution fusion, i.e., obtaining a high spatial and spectral resolution multispectral (MS) image using the available low spatial resolution MS and the high spatial resolution Panchromatic (Pan) image. Our approach is based on the idea of compressive sensing (CS) and graph cuts. Assuming that both the MS and Pan images have the same sparseness, a close approximation to the MS image is obtained from the Pan image using the theory of compressive sensing and ${l_1}$ minimization. We then use regularization framework to obtain fused image. The low resolution (LR) MS image is modeled as degraded and noisy version of fused image in which degradation matrix entires estimated using the close approximation are used. The regularization is carried out by using truncated quadratic smoothness prior which takes care of preservation of the discontinuities in the fused image. A suitable energy function is then formed consisting of data fitting term and prior term. Minimization of the energy function is carried out using a computationally efficient graph cuts optimization to obtain final fused image. Advantage of our approach is that the Pan and MS images need not be registered. This is because, we are not directly using the Pan digital numbers to derive the fused image. The effectiveness of the proposed method is illustrated by conducting experiments on real satellite images. Subjective and quantitative comparison of the proposed method with the state-of-the-art approaches indicates efficacy of our approach.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Fusion of Multispectral Images by Extension of the Pan-Sharpening ARSIS
    • Authors: Sylla; D.;Minghelli-Roman, A.;Blanc, P.;Mangin, A.;Hembise Fanton d'Andon, O.;
      Pages: 1781 - 1791
      Abstract: Some remote sensing applications, like coastal zone monitoring, require images having at the same time a high spatial, spectral, and temporal resolution. However, for the moment, no sensor provides these three characteristics at once. The medium resolution imaging spectrometer (MERIS) sensor combines high spectral resolution (15 bands) and low spatial resolution (300 m), whereas the enhanced thematic mapper (ETM) sensor combines reverse characteristics. The main objective of this work is to extend the pan-sharpening ARSIS method to the fusion of two multispectral images and to compare it with two other existing methods: the couple non-negative matrix factorization (CNMF) and a multisensor and multiresolution technique (). We then apply these three different methods to two sets of MERIS and ETM data: a synthetic set created from a Hyperion image in order to provide the reference image that would be acquired by a perfect sensor for validation, and a real set composed by MERIS and ETM co-registrated images. The results showed that the ARSIS method extended to the fusion of two multispectral images provides better statistical and visual results than the two other methods, on both synthetic and real datasets, and it is better adapted to water than to land applications.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Two-Step Sparse Coding for the Pan-Sharpening of Remote Sensing Images
    • Authors: Jiang; C.;Zhang, H.;Shen, H.;Zhang, L.;
      Pages: 1792 - 1805
      Abstract: Remote sensing image pan-sharpening is an important way of enhancing the spatial resolution of a multispectral (MS) image by fusing it with a registered panchromatic (PAN) image. The traditional pan-sharpening methods often suffer from color distortion and are still far from being able to synthesize a real high-resolution MS image, as could be directly acquired by a better sensor. Inspired by the rapid development of sparse representation theory, we propose a two-step sparse coding method with patch normalization (PN-TSSC) for image pan-sharpening. Traditional one-step sparse coding has difficulty in choosing dictionary atoms when the structural information is weak or lost. By exploiting the local similarity between the MS and PAN images, the proposed sparse coding method deals with the dictionary atoms in two steps, which has been found to be an effective way of overcoming this problem. The experimental results with IKONOS, QuickBird, and WorldView-2 data suggest that the proposed method can effectively improve the spatial resolution of a MS image, with little color distortion. The pan-sharpened high-resolution MS image outperforms those images fused by other traditional and state-of-the-art methods, both quantitatively and perceptually.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • A Pan-Sharpening Based on the Non-Subsampled Contourlet Transform:
           Application to Worldview-2 Imagery
    • Authors: Chikr El-Mezouar; M.;Kpalma, K.;Taleb, N.;Ronsin, J.;
      Pages: 1806 - 1815
      Abstract: Two pan-sharpening methods based on the non-subsampled contourlet transform (NSCT) are proposed. NSCT is very efficient in representing the directional information and capturing intrinsic geometrical structures of the objects. It has characteristics of high resolution, shift-invariance, and high directionality. In the proposed methods, a given number of decomposition levels are used for multispectral (MS) images while a higher number of decomposition levels are used for Pan images relatively to the ratio of the Pan pixel size to the MS pixel size. This preserves both spectral and spatial qualities while decreasing computation time. Moreover, upsampling of MS images is performed after NSCT and not before. By applying upsampling after NSCT, structures and detail information of the MS images are more likely to be preserved and thus stay more distinguishable. Hence, we propose to exploit this property in pan-sharpening by fusing it with detail information provided by the Pan image at the same fine level. The proposed methods are tested on WorldView-2 datasets and compared with the standard pan-sharpening technique. Visual and quantitative results demonstrate the efficiency of the proposed methods. Both spectral and spatial qualities have been improved.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Super-Resolution Land Cover Mapping with Spatial–Temporal
           Dependence by Integrating a Former Fine Resolution Map
    • Authors: Ling; F.;Li, X.;Du, Y.;Xiao, F.;
      Pages: 1816 - 1825
      Abstract: Super-resolution mapping (SRM) is a technique to predict spatial locations of land cover classes at the subpixel scale within coarse resolution remotely sensed image pixels. Due to the lack of information about the spatial pattern of land covers, uncertainty always exists in resultant fine-resolution land cover maps. In the present work, by integrating a former fine-resolution land cover map, the spatial dependence used in existing SRM algorithms is extended into a novel spatial–temporal dependence used in the SRM algorithm (SRM_STD). The spatial–temporal dependence consists of the spatial dependences of former fine-resolution land cover map, the spatial dependences of latter coarse resolution fraction images, and the corresponding dependence between former and latter land cover maps. By considering the spatial–temporal dependences of subpixels, SRM_STD can inherit valuable land cover information from the former fine-resolution land cover map, and reduce the uncertainty of SRM to a large extent. The performance of the proposed SRM_STD algorithm is assessed using a subset of the National Land Cover Database datasets and land cover maps produced by Landsat imagery in an area of rapid urban expansion. The results of two experiments show that the former dependence has little influence on the result, whereas the corresponding dependence plays a crucial role on the result. With a large weight of corresponding dependence, the proposed SRM_STD algorithm can produce fine-resolution land cover maps with higher accuracy than those of hard classification and the pixel swapping algorithm.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • A Fast and Accurate Orthorectification Algorithm of Aerial Imagery Using
           Integer Arithmetic
    • Authors: French; J.C.;Balster, E.J.;
      Pages: 1826 - 1834
      Abstract: In the past decade, imaging systems have increased in size and quality while decreasing in cost. As the cost has decreased, many aerial imaging applications have become practical such as tracking, vegetation indexing, coast line monitoring, etc. However, many of these applications require geo-location and orthorectification to enable analysis. Orthorectification is a computationally expensive process due to floating-point operations and divisions in the algorithm. To reduce the computational cost of on-board processing, two novel algorithm modifications are proposed. One modification is projection utilizing fixed-point arithmetic. Fixed-point arithmetic removes the floating-point operations and reduces the processing time by operating only on integers. The second modification is replacement of the division inherent in projection with a multiplication of the inverse. With these modifications, the processing time of the projection is reduced by a factor of 1.2 $mmbtimes$ with an average pixel position error of 0.5% of a pixel size for 128-bit integer processing and over 2 $mmbtimes$ with an average pixel position error of less than 15% of a pixel size for a 64-bit integer processing.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Open Access
    • Pages: 1835 - 1835
      Abstract: Advertisement: This publication offers open access options for authors. IEEE open access publishing.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
  • Together, we are advancing technology
    • Pages: 1836 - 1836
      Abstract: Advertisement: Now over three million documents in IEEE Xplore. Thank you for your authorship.
      PubDate: May 2014
      Issue No: Vol. 7, No. 5 (2014)
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