Showing papers on "Moving target indication published in 2017"

Robust Adaptive Beamforming for Fast-Moving Target Detection With FDA-STAP Radar

Abstract: Frequency diverse array (FDA), which employs a small frequency increment across the array elements, is able to resolve range ambiguity. However, the frequency diversity results in angle-Doppler-defocusing of target especially at a high speed in space-time adaptive processing (STAP) radar, thus, causing serious detection performance degradation. In this paper, a robust adaptive beamforming approach is proposed for the FDA-STAP radar to enhance fast-moving target detection performance. In our solution, a large feasible region is employed to include the true steering vector of target. To avoid the trivial solution, an angle-Doppler-defocusing steering vector constraint is devised and incorporated into the large feasible region. The problem is formulated as a nonconvex quadratically constrained quadratic program which is efficiently solved via semidefinite relaxation technique. Because the retrieved steering vector of target is close to the true one, the performance is significantly improved. It is demonstrated via computer simulations that the proposed algorithm is superior to the state-of-the-art methods, which includes maintaining the mainlobe of the beampattern and improving the signal-to-clutter-plus-noise ratio performance.

Track-Before-Detect Strategies for Radar Detection in G0-Distributed Clutter

Abstract: This paper considers target detection via dynamic-programming based track-before-detect (DP-TBD) for radar systems. The clutter is modeled usingenlr G0 distribution, which is usually used to model clutter received from high-resolution radars and radars working at small grazing angles. Two target models, namely, Swerling 0 and 1 models, are considered to capture the radar cross section changes over time. DP-TBD techniques that integrate amplitude suffer from significant performance loss in this case due to the high likelihood of target-like outliers. In this paper, the log-likelihood ratio (LLR) is used in the integration process of DP-TBD, taking the place of amplitude, to enhance radar detection performance. The expressions for the LLR for the above target models are derived first. However, neither of them has a closed-form solution. In order to reduce the complexity of evaluating the LLR, efficient but accurate approximation methods are proposed. Then the approximated LLR is used in the integration process of DP-TBD. Simulations are used to examine the efficiency of the approximation methods as well as the performances of different DP-TBD strategies.

Preliminary Research of Low-RCS Moving Target Detection Based on Ka-Band Video SAR

Abstract: Conventional synthetic aperture radar (SAR) ground moving target detection is only effective for targets with high radar cross section (RCS), and its performance is degraded by focusing distortion caused by the motion of the target. This letter proposes a new low-RCS moving target detection method which exploits the target’s shadow using high-resolution sequential images captured by a Ka-band video SAR system. First, the characteristics of target shadow are investigated, which are mainly influenced by the size of the target, the incidence of the radar beam, and the target velocity. Then the presented method based on video SAR system is described, and its moving target detection performance is also analyzed. As a preliminary study, a simulated experiment is conducted in which the signal of a low-RCS moving target is simulated and inserted into real airborne Ka-band video SAR images. The results demonstrate the feasibility of the proposed method for low-RCS moving target detection.

An Approach for Refocusing of Ground Moving Target Without Target Motion Parameter Estimation

Abstract: In synthetic aperture radar (SAR), long integration time may induce range migration and Doppler frequency migration of a received signal, which may degrade the SAR imaging performance of ground moving targets. Most of the conventional algorithms deal with the problems of range migration and Doppler frequency migration based on parameter searching. However, the exhaustive searching of target motion parameters may result in heavy computational burden. To avoid this problem, this paper proposes a new imaging method for ground moving targets without target motion parameter estimation. First, Keystone transform is applied to correct the range walk. Second, range curvature is compensated by the matched filtering function. Third, Doppler frequency migration is compensated via multiplying the data in range- and azimuth-time domains by its reversed conjugate data according to the equal interval sampling of the azimuth slow time, which avoids the searching procedure for target motion parameter estimation. Finally, the signal energy will be well accumulated in the range–Doppler domain, and thus, the moving targets can be efficiently recognized in the focused image. The major advantage of the proposed method is that it can obtain well-focused images of all targets in one processing step without target motion parameter estimation; thus, it is computationally efficient. Both simulated and real data processing results are used to validate the effectiveness of the proposed method.

Image-Based Target Detection and Radial Velocity Estimation Methods for Multichannel SAR-GMTI

Abstract: In order to enhance the performance of spaceborne synthetic aperture radar–ground moving target indication (SAR-GMTI) systems, multichannel systems with large and preferably nonuniform baselines are required. In this paper, SAR-GMTI algorithms for multichannel SAR systems, which we call multichannel displaced phase center antenna (DPCA), multichannel along track interferometry (ATI), and multichannel DPCA-ATI, are presented. Multichannel DPCA is a deterministic algorithm for clutter and azimuth ambiguity suppression. It successfully suppresses not only uniform azimuth ambiguities but also nonuniform isolated ones, since it does not require uniform clutter covariance assumption as adaptive algorithms do. Multichannel ATI and multichannel DPCA-ATI are the algorithms for target radial velocity estimation. Both of them reduce the target radial velocity ambiguities, which arise with the long baseline systems, by exploiting the multiple receive channel signals. And multichannel DPCA-ATI further achieves robust performance to clutter influence by suppressing the clutter and the azimuth ambiguity in advance. The performances of the proposed algorithms are shown through airborne Ku-band three-channel SAR experiments. It is shown that the multichannel DPCA suppresses strong azimuth ambiguity up to more than 20 dB, and the accuracy of the radial velocity estimation of the multichannel DPCA-ATI is on the order of 0.1 m/s. Furthermore, statistical performance analysis is presented to discuss the potential performance on the spaceborne system.

GMTI and Parameter Estimation via Time-Doppler Chirp-Varying Approach for Single-Channel Airborne SAR System

Abstract: Conventionally, a single-channel synthetic aperture radar (SC-SAR) system can hardly detect weak moving targets simply. In this paper, a time-Doppler chirp-varying (TDCV) filter is proposed for ground moving target indication and parameter estimation with the airborne SC-SAR system. The proposed method is easy to implement and mainly includes three steps. First, a traditional 2-D frequency range-Doppler algorithm is used to generate an original image. Second, the second-order range cell migration (RCM) phase term is partly compensated in the range frequency and azimuth time domain, and the rest of second-order RCM phase term is compensated in 2-D frequency domain. The whole processing, which is referred to as the TDCV approach, is employed to acquire a new TDCV image. Third, compared the original image with the new image, the clutter scatterers are nearly motionless while the moving targets are translated along the range direction due to their nonzero radial velocities. After the cancellation between two normalized images, the clutter background would be significantly suppressed since the two images generated by the same data. As a result, the moving targets can be indicated and the range difference of the moving target between two images can be exploited to estimate their radial velocities. The results obtained by applying the proposed method into a set of real SAR data are consistent with the analysis presented in this paper.

Moving and stationary target detection scheme using coherent integration and subtraction for automotive FMCW radar systems

Abstract: In this paper, we proposed an automotive radar signal processing scheme for target detection, tracking, and classification. The target detection part consists of range-processing, moving target indication using the coherent phase difference method, Doppler-processing, digital beam forming, and hit decisions to determine the moving target and strong stationary targets. To delete ghost targets and compensate for missing targets, we design the target tracking stage to include clustering, data association, track management, and a track filter. Finally, the target classification stage selects the range-, velocity-, and angle-ROIs (Regions Of Interest) based on the output from the target track aspect, and analyzes the 3D profiles extracted during the target detection stage. In the experimental results, we verify the proposed radar signal processing scheme using a 24 GHz FMCW transceiver with a single antenna.

Non-coherent Radar Detection Performance in Medium Grazing Angle X-Band Sea Clutter

Abstract: This paper describes the non-coherent target detection performance of an airborne surface surveillance radar in the presence of medium grazing angle sea clutter. In the absence of frequency agility, the temporal correlation of the sea clutter can be significant and if it is not accounted for in the clutter model, the required signal to interference ratio for a given probability of detection will be incorrect by several decibels, resulting in overestimated performance. This paper describes a robust method for calculating the detection probability for both K and Pareto compound sea-clutter distributions. Empirical models of the amplitude distribution and the speckle correlation are used to determine the expected detection performance given different collection geometries and environmental conditions with the output used to determine the minimum detectable target radar cross section in a detection scenario.

An ML-Based Radial Velocity Estimation Algorithm for Moving Targets in Spaceborne High-Resolution and Wide-Swath SAR Systems

Abstract: Multichannel synthetic aperture radar (SAR) is a significant breakthrough to the inherent limitation between high-resolution and wide-swath (HRWS) compared with conventional SAR. Moving target indication (MTI) is an important application of spaceborne HRWS SAR systems. In contrast to previous studies of SAR MTI, the HRWS SAR mainly faces the problem of under-sampled data of each channel, causing single-channel imaging and processing to be infeasible. In this study, the estimation of velocity is equivalent to the estimation of the cone angle according to their relationship. The maximum likelihood (ML) based algorithm is proposed to estimate the radial velocity in the existence of Doppler ambiguities. After that, the signal reconstruction and compensation for the phase offset caused by radial velocity are processed for a moving target. Finally, the traditional imaging algorithm is applied to obtain a focused moving target image. Experiments are conducted to evaluate the accuracy and effectiveness of the estimator under different signal-to-noise ratios (SNR). Furthermore, the performance is analyzed with respect to the motion ship that experiences interference due to different distributions of sea clutter. The results verify that the proposed algorithm is accurate and efficient with low computational complexity. This paper aims at providing a solution to the velocity estimation problem in the future HRWS SAR systems with multiple receive channels.

A low-cost through-the-wall FMCW radar for stand-off operation and activity detection

Abstract: In this paper we present a new through-wall (TW) FMCW radar system. The architecture of the radar enables both high sensitivity and range resolutions of <1.5 m. Moreover, the radar employs moving target indication (MTI) signal processing to remove the problematic primary wall reflection, allowing higher signal-to- noise and signal-to-interference ratios, which can be traded-off for increased operational stand-off. The TW radar operates at 5.8 GHz with a 200 MHz bandwidth. Its dual-frequency design minimises interference from signal leakage, and permits a baseband output after deramping which is digitized using an inexpensive 24-bit off-the-shelf sound card. The system is therefore an order of magnitude lower in cost than competitor ultrawideband (UWB) TW systems. The high sensitivity afforded by this wide dynamic range has allowed us to develop a wall removal technique whereby high-order digital filters provide a flexible means of MTI filtering based on the phases of the returned echoes. Experimental data demonstrates through-wall detection of individuals and groups of people in various scenarios. Target positions were located to within ±1.25 m in range, allowing us distinguish between two closely separated targets. Furthermore, at 8.5 m standoff, our wall removal technique can recover target responses that would have otherwise been masked by the primary wall reflection, thus increasing the stand-off capability of the radar. Using phase processing, our experimental data also reveals a clear difference in the micro-Doppler signatures across various types of everyday actions.

Using SVD-FRFT Filtering to Suppress First-Order Sea Clutter in HFSWR

Abstract: This letter presents a novel signal processing method for HF surface wave radar that offers a solution to suppress significant sea clutter interference Conventional clutter rejection methods, when the target signal and first-order sea clutter are mixed in the Doppler spectrum, tend to eliminate both the target signal and clutter without distinction To address this problem, the frequency-modulated difference between the target signal and clutter is considered Target echoes can be characterized as a linear-frequency modulation signal in long coherent time, while first-order sea clutter can be regarded as a superposition of several single-frequency signals Based on the hybrid use of singular value decomposition (SVD) and the fractional Fourier transform (FRFT), SVD-FRFT filtering is conducted to suppress the components of the first-order sea clutter without impairing the target signals The effectiveness of this method is illustrated by simulation and experimental results It is further demonstrated that SVD-FRFT filtering can improve the signal-to-clutter ratio (SCR) to up to 40 dB for different SCRs

Coherent method for ground-moving target indication and velocity estimation using Hough transform

Abstract: In this study, a novel algorithm for detecting the ground-moving targets and estimating their motion parameters is proposed Based on the fact that clutter has a certain phase pattern, clutter cancellation is accomplished using a phase modification and finite impulse response filtering Then a type of coherent Hough transform is utilised to estimate the moving target velocity By employing the coherent Hough transform, the proposed algorithm leads to the significant signal-to-noise ratio (SNR) and signal-to-clutter ratio improvement in comparison with similar previous Hough- or Radon-based ground-moving target indication and velocity estimation methods In fact, uncorrelated noise samples have random phases that cancel each other, therefore, a noticeable SNR improvement would be achieved Moving target detection is done by conventional constant false alarm rate (CFAR) techniques over different range gates

GNSS-based passive radar for maritime surveillance: Long integration time MTI technique

Abstract: The exploitation of the Global Navigation Satellite Systems (GNSS) as transmitters of opportunity in passive radar systems for maritime surveillance is particularly attractive because of the main advantages consisting in a global coverage (even in open sea) and in the availability of multiple sources (different satellites and constellations). The main drawback stays in the restricted power budget provided by navigation satellites. This makes necessary to conceive, define and develop innovative moving target detection techniques specifically tailored for the system under consideration, in order to make this technology a powerful tool for persistent surveillance of sea areas of interest. To this aim, a long integration time Maritime Moving Target Indication technique is proposed in this work, and its effectiveness is proved against experimental data involving a small maritime target, not detectable by conventional MTI techniques. Obtained results prove the feasibility of a maritime MTI mode for GNSS based passive systems.

Clutter suppression and GMTI for hypersonic vehicle borne SAR system with MIMO antenna

Abstract: This study proposes a clutter suppression approach and the corresponding ground moving target imaging algorithm for hypersonic vehicle (HSV) borne synthetic aperture radar (SAR) system with multiple-input-multiple-output (MIMO) antenna. HSV-borne radar platforms fly with a high speed, which can lead to severe Doppler ambiguity, and the radar system usually cannot provide enough channel freedom degree for clutter suppression. In this study, an SAR ground moving target indication (GMTI) approach with MIMO antenna is presented for HSV-borne radar. Compared with the traditional multichannel SAR GMTI methods, the proposed approach can provide more space freedom degree and obtain a wider imaging swath without decreasing pulse repetition frequency. Besides, the improved deramp space-time adaptive processing method decreases the ambiguity times of the ground clutter and focuses the moving target. The simulation results validate the effectiveness of the proposed method.

Ground Moving Target Imaging and Motion Parameter Estimation With Airborne Dual-Channel CSSAR

Abstract: This paper deals with the issue of ground moving target imaging and motion parameter estimation with an airborne dual-channel circular stripmap synthetic aperture radar (CSSAR) system. Although several methods of ground moving target motion parameter estimation have been proposed for the conventional airborne linear stripmap SAR, they cannot be applied to airborne CSSAR because the range history of a ground moving target for airborne CSSAR is different than that for airborne linear stripmap SAR. In this paper, the moving target’s range history for airborne dual-channel CSSAR and the target signal model after the displaced phase center antenna processing are derived, and a new ground moving target imaging and motion parameter estimation algorithm is developed. In this algorithm, the estimation of baseband Doppler centroid and its compensation are first performed. Then focusing is implemented in the 2-D frequency domain via phase multiplication, and the target is focused in the SAR image without azimuth displacement due to the compensation of the Doppler shift caused by its motion. Finally, the target’s motion parameters are estimated with its Doppler parameters and its position in the SAR image. Numerical simulations are conducted to validate the derived range history and the performance of the proposed algorithm.

A Moving Target Imaging Algorithm for HRWS SAR/GMTI Systems

Abstract: For a target illuminated by a high-resolution and wide-swath synthetic aperture radar system, the velocity is estimated based on sparse direction-of-arrival estimation. Then, the space-time adaptive processing algorithm is utilized to suppress the clutter and reconstruct the spectra of the target, followed by the traditional target imaging. The performance of the proposed algorithm is analyzed in detail. The proposed algorithm can retain the power of the moving target, and is free of searching.

First Spaceborne SAR-GMTI Experimental Results for the Chinese Gaofen-3 Dual-Channel SAR Sensor

Abstract: In spaceborne synthetic aperture radar (SAR) sensors, it is a challenging task to detect ground slow-moving targets against strong clutter background with limited spatial channels and restricted pulse repetition frequency (PRF). In this paper, we evaluate the image-based dual-channel SAR-ground moving target indication (SAR-GMTI) workflow for the Gaofen-3 SAR sensor and analyze the impact of strong azimuth ambiguities on GMTI when the displaced phase center antenna (DPCA) condition is not fully satisfied, which has not been demonstrated yet. An effective sliding window design technique based on system parameters analysis is proposed to deal with azimuth ambiguities and reduce false alarm. In the SAR-GMTI experiments, co-registration, clutter suppression, constant false alarm rate (CFAR) detector, vector velocity estimation and moving target relocation are analyzed and discussed thoroughly. With the real measured data of the Gaofen-3 dual-channel SAR sensor, the GMTI capability of this sensor is demonstrated and the effectiveness of the proposed method is verified.

Dictionary-Based Principal Component Analysis for Ground Moving Target Indication by Synthetic Aperture Radar

Abstract: This letter addresses an efficient algorithm for ground moving target detection and estimation of motion parameters by synthetic aperture radar (SAR). The proposed method outperforms the conventional robust principal component analysis (RPCA)–based ground moving target indication (GMTI) methods that were proposed in the literature. The ability to estimate the radial and along-track velocities of ground moving targets is provided. The rank constraint in the conventional RPCA problem will be automatically relaxed by employing a dictionary matrix for clutter representation. Thus, the new optimization problem will be solved easier with lower degrees of freedom. Furthermore, this dictionary helps to suppress the clutter of higher Doppler frequencies in case of wind blowing scenarios and intrinsic clutter motion modeling. By employing another dictionary matrix for all possible moving targets with different location and velocity, each solution of the optimization problem will be reasonable as it corresponds to a moving target. Although, the two dictionary matrices impose extra computational burden, this load will be prepared prior to other GMTI processing by the information of the SAR system and scenario parameters. Moreover, the algorithm is proposed for the single-channel SAR configurations and has lower computational load than the conventional RPCA-GMTI methods that have to process the recorded data of multichannel systems. Numerical and experimental results are used to evaluate the performance of the proposed method and validate the theoretical discussions.

Clutter Cancellation Along the Clutter Ridge for Airborne Passive Radar

Abstract: This letter examines the problem of clutter cancellation in airborne passive radar. This problem is exacerbated by the Doppler spread of clutter due to the receiver motion, since targets falling in the clutter Doppler band will be canceled. To address this problem, a least mean square-based algorithm is proposed for the sidelooking airborne passive radar. Making use of the directional dependence of the clutter Doppler frequency, this algorithm cancels clutter along the clutter ridge and thus avoids the cancellation of targets. Simulations with the experimental data show that clutter can be canceled ideally with the proposed algorithm and signal-to-noise ratio losses are slight, for example, the losses are within 1 dB for targets with radial velocity greater than 10 m/s.

Multipulse Adaptive Coherence for Detection in Wind Turbine Clutter

Abstract: Radar tracking of aircraft targets at low elevation angles can be complicated by clutter from wind turbines, which we define to be clutter. In this paper, we study detection in a staring pulse-Doppler radar. By exploiting the second-order correlation structure of this wind-turbine clutter we derive a target detector that uses a sequence of adaptive coherence scores. The detector uses a multipulse coherence statistic consisting of an incoherent geometric average of coherently computed adaptive coherence scores. The detector compares favorably to a multipulse coherence detector that uses no modeling or estimation of the clutter.

Narrow-Band Clutter Mitigation in Spectral Polarimetric Weather Radar

Abstract: In this paper, a new clutter suppression method, named the moving double spectral linear depolarization ratio (MDsLDR) filter, is put forward to mitigate narrow-band clutter in weather radars. The narrow-band clutter observed in the Doppler domain includes: 1) stationary clutter such as ground clutter and 2) nonstationary clutter such as artifacts caused by the radar system itself or external sources. These artifacts are difficult to remove, because they are not confined to specific azimuth and range bins. Based on the difference of the spectral-polarization feature and the spectral continuity of precipitation and clutter, the MDsLDR filter can remove ground clutter, artifacts, and noise. The performance of the newly proposed filter is assessed by data collected by the Doppler-polarimetric IRCTR Drizzle Radar. Three precipitation cases are considered in this paper: moderate/light precipitation, convective precipitation with hook-echo signature, and light precipitation with severe artifact contamination. Furthermore, the implementation of the MDsDLR filter requires relatively low computation complexity, so that the MDsLDR filter can be operated in real time.

Filters that mitigate waveform modulation of radar clutter

Abstract: Moving target indication (MTI) radars will require modified signal processing to be able to employ pulse-to-pulse agile waveforms. The main problem with conventional processing is that matched-filter pulse compression leads to range-sidelobe modulation (RSM) of clutter. Due to the fact that range sidelobes differ on each pulse, clutter energy that leaks into these sidelobes cannot be cancelled by subsequent processing. This study derives a figure-of-merit for pulse-compression filters that quantifies the signal-to-interference-plus-noise ratio (SINR) loss that results from RSM. Optimising this figure-of-merit results in sets of filters that mitigate RSM by producing matched sidelobes. The proposed filters are compared to low-sidelobe mismatch filters designed separately for each pulse. Simulation results indicate that an MTI radar could achieve a 5–10 dB improvement in SINR by using the proposed filters instead of low-sidelobe filters.

Ground Moving Target Indication for High-Resolution Wide-Swath Synthetic Aperture Radar Systems

Abstract: This letter presents a new scheme for ground moving target indication in high-resolution wide-swath (HRWS)-synthetic aperture radar (SAR) systems. The asymmetry of the Doppler spectra is measured to extract the range bins with moving targets. To improve the computational efficiency, only the extracted range bins are used to restore the unambiguous Doppler spectra. The two-look processing technique is then applied to generate two looks and moving targets are indicated by comparing the difference between the two looks. In this detection scheme, the configuration of the conventional HRWS-SAR system remains unchanged and no additional receiving channels are needed. The experimental results show the effectiveness of this detection scheme.

Multiple human-targets location and tracking method based on multichannel phase comparison location

Abstract: The present invention discloses a multiple human-targets location and tracking method based on multichannel phase comparison location. The method comprises: based on a linear frequency modulation continuous wave radar system of single input multiple output, employing the moving target indication and de-mean method to perform preprocessing of experiment data and perform diploid interpolation refinement distance dimension windowing Fourier transform of each period of the echo data so as to obtain object distance information according to the distance spectrum of an object; obtaining the object distance information according to the object distance; extracting the phase information corresponding to the target from the peak value where a frequency spectrum object is located; fusing the phase information of different receiving channels, calculating the phase differences among different receiving channels, calculating the azimuth or the pitch angle of the object, and combining the object distance information to calculate the location result of the object at a two-dimensional plane or a three-dimensional plane; and finally, employing the Kalman filtering method to realize the tracking of the target. The multiple human-targets location and tracking method based on the multichannel phase comparison location can perform detection, location and tracking of a plurality of human body objects indoors and outdoors so as to effectively reject multiple paths while keeping the target and perform accurate location of the object.

Evaluation of pulse compression techniques for X-band radar systems

Abstract: Detection of moving targets using a moving target indication (MTI) type radar system has two important tasks viz., determination of the precise range and the velocity of the target. Precise range calculations require the radar system to have a high range resolution ability. An important trade-off factor in radar systems is between range resolution, that requires shorter pulse, and transmitted pulse energy, that necessitates longer pulses. Pulse compression is a technique that helps overcome this tradeoff by modulating the pulses to be transmitted. Various frequency and phase modulation techniques can be used to achieve compression of the pulses. In the discussions here, the linear frequency modulation (LFM) and non-linear frequency modulation (NLFM) methods are compared with phase modulation techniques such as Barker codes and polyphase codes. Two new approaches for pulse compression that employ quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) are also presented. These pulse compression techniques are compared for relative performance using parameters such as the peak-sidelobe ratio (PSLR), pulse compression ratio and Doppler tolerance. Results show that polyphase codes have high Doppler tolerance. QAM and QPSK, like polyphase codes, are not limited by number of bits that can be used within a pulse, and thus can be used to achieve good compression ratios.

Target parameter estimation in moving transmitter moving receiver forward scatter radar

Abstract: This paper focuses on the estimation of target's motion parameters in a moving transmitter/moving receiver forward scatter radar scenario. An extension of the quasicoherent processing initially developed for stationary FSR mode of operation is introduced. This offers an estimation of the target's trajectory in a general case where transmitter and receiver can be moving. Simulated and real data are used to analyse the performance of the presented processing.

On the Statistics of Coherence Estimators for Textured Clutter Plus Noise

Abstract: This letter presents a theoretical analysis of the impact of thermal noise on the statistics of the classical as well as a modified estimator for the cross-correlation coefficient between two receive channels, which follow a noisy compound clutter model. This correlation coefficient, in the synthetic aperture radar (SAR) context often called coherence, is widely used as an important quality parameter in the field of SAR interferometry, SAR change detection, and SAR ground moving target indication. Based on a novel closed-form expressions for the probability density function (pdf) for integer number of averaged samples (or looks), it is shown that, contrary to widespread belief, the clutter texture does not cancel out when the noise contribution is taken into account. It is further demonstrated that the new pdfs can be used to derive the bias and variance of the sample coherence in analytical closed form. Thereby, the impact of the texture on the estimators is analyzed.

Analysis of deceptive moving target generated by single jammer in multi-channel SAR-GMTI

Abstract: Based on three-channel SAR-GMTI system, the velocity and location of the deceptive moving target generated by single jammer are studied Study result shows that both the deceptive stationary target and moving target can be considered as moving target, and the estimated azimuth location which has nothing to do with the setting value is the same as jammer