Showing papers on "Moving target indication published in 2013"

Knowledge-Aided (Potentially Cognitive) Transmit Signal and Receive Filter Design in Signal-Dependent Clutter

Abstract: We consider the problem of knowledge-aided (possibly cognitive) transmit signal and receive filter design for point-like targets in signal-dependent clutter. We suppose that the radar system has access to a (potentially dynamic) database containing a geographical information system (GIS), which characterizes the terrain to be illuminated, and some a priori electromagnetic reflectivity and spectral clutter models, which allow the raw prediction of the actual scattering environment. Hence, we devise an optimization procedure for the transmit signal and the receive filter which sequentially improves the signal- to-interference-plus-noise ratio (SINR). Each iteration of the algorithm, whose convergence is analytically proved, requires the solution of both a convex and a hidden convex optimization problem. The resulting computational complexity is linear with the number of iterations and polynomial with the receive filter length. At the analysis stage we assess the performance of the proposed technique in the presence of either a homogeneous ground clutter scenario or a heterogeneous mixed land and sea clutter environment.

A Generalization of DPCA Processing for Multichannel SAR/GMTI Radars

Abstract: This paper generalizes the well-known displaced- phase-center antenna (DPCA) method for efficient ground moving target indication (GMTI) with a two-channel synthetic aperture radar (SAR) to any multichannel SAR/GMTI radars independent of the number of receive channels. This processing method called extended DPCA (EDPCA) is derived in this paper and is applied to data acquired with the Canadian RADARSAT-2 satellite. The expected GMTI performance of RADARSAT-2 after EDPCA processing is compared to results achieved with measured RADARSAT-2 data recorded during several trials in order to validate the developed theory.

Two-Step Detector for RADARSAT-2's Experimental GMTI Mode

Abstract: Ground moving target indication (GMTI) from space has currently raised interest from wide area traffic monitoring as well as for military surveillance activities. This paper presents theoretical and real data GMTI results of RADARSAT-2's Moving Object Detection Experiment based on data gathered during the commissioning phase in February 2008. The proposed constant false alarm rate target detection is based on a novel and thorough analysis of the multilook test statistics. The practical and relevant case in which a target, for instance a passenger car, occurs in only l-out-of-n ground resolution multilook cells is analyzed. This general case is analyzed for the determination of adequate detection thresholds as well as the anticipated probability of detection Pd particularly with regard to a varying degree of terrain heterogeneity and target characteristics. The overall false alarm rate Pfa is significantly reduced by a complementary detection step using the along-track interferometric phase. The validity of these theoretical findings are corroborated by real two-channel space-based synthetic aperture radar-GMTI data of civilian vehicles of opportunity, whose main parameters have been estimated and compared with the derived Cramer-Rao Bounds.

A Parametric Moving Target Detector for Distributed MIMO Radar in Non-Homogeneous Environment

Abstract: This paper considers moving target detection (MTD) with distributed multi-input multi-output (MIMO) radars in non-homogeneous environments, where the received disturbance signal (clutter and noise) exhibits non-homogeneity in not only power but also covariance structure from one transmit-receive (TX-RX) antenna pair to another as well as across different test cells. To address this problem, we introduce a parametric approach by employing a set of distinctive auto-regressive (AR) models, one for each TX-RX pair, to model the non-homogeneous disturbance signals. We develop a parametric generalized likelihood ratio test (PGLRT), referred to as the MIMO-PGLRT detector, for MTD in distributed MIMO radars. The MIMO-PGLRT detector, which consists of local adaptive subspace detection, non-coherent combining using local decision variables, and a global threshold comparison, is shown to asymptotically achieve constant false alarm rate (CFAR). We also investigate the target velocity estimation problem, an integral part of MTD, and develop its maximum likelihood estimator. The Cramer-Rao bound, in both the exact and asymptotic forms, respectively, is examined to shed additional light to the problem. Numerical results are presented to demonstrate the effectiveness of the proposed methods.

New Antivelocity Deception Jamming Technique using Pulses with Adaptive Initial Phases

Abstract: An effective electronic counter-countermeasures (ECCM) technique for a moving target indication/pulsed Doppler (MTI/PD) radar system against velocity deception jamming is proposed. A novel radar signaling strategy is outlined based on variations of the initial phases of the transmitted pulses in pulse repetition interval (PRI) domain. It makes the Doppler spectrum of the false targets, created by a digital radio frequency memory (DRFM) repeat-back jammer, form a notch around the Doppler frequency of the true one. The penalty function and corresponding algorithm for designing adaptive initial phases are given. We also present an approach of the multi-channel matched filter processing to estimate the manner, by which a DRFM repeat jammer operates, and the parameters of the false targets. The working flow of an MTI/PD radar for countering velocity deception jamming is investigated. Simulation results show the effectiveness of the above methods.

Change Detection Analysis of Humans Moving Behind Walls

Abstract: In this paper, we consider the problem of detection of humans behind walls and inside enclosed structures using radars. We use change detection techniques to mitigate the heavy clutter caused by strong reflections from exterior and interior walls. To improve spatial resolution, we apply multiple-input multiple-output (MIMO) configurations to moving target indication (MTI). We examine change detection formulation and performance when clutter removal is performed pre- and postbeamforming. Using signal multiplexing from two transmitters and several receiver positions, we show that the virtual array (coarray) implementing the prebeamforming change detection MIMO scheme permits enhanced clutter rejection and improvement in imaging resolution of moving targets without increasing the physical aperture. Laboratory experiments are conducted to validate the proposed approaches with targets walking behind walls.

Ground Moving Target Extraction in a Multichannel Wide-Area Surveillance SAR/GMTI System via the Relaxed PCP

Abstract: This letter presents a novel approach for extracting moving targets in a multichannel wide-area surveillance radar system. In the algorithm, after proper preprocessing and matrix combination, the combined matrix of radar echoes can be regarded as the superposition of three matrices, namely, a low-rank matrix of ground clutter, a sparse matrix of moving targets, and an entry-wise matrix of noise component. Then, the recently proposed relaxed version of principal component pursuit is used to realize ground clutter (low-rank matrix) and moving target (sparse matrix) separation under the influence of entry-wise noise. Both simulation and real data processing results are provided to demonstrate the effectiveness of the proposed method. In addition, the results show the advantage of the proposed method in a nonhomogeneous environment when compared with a reduced-dimension space-time adaptive processing method.

Ground Moving Target Indication in SAR Images by Symmetric Defocusing

Abstract: A new algorithm is presented to indicate ground moving targets in synthetic aperture radar images. Two filters, which differ only in the signs of the phase responses, are used to defocus the complex image respectively. In the two defocused images, each stationary target is blurred to the same extent, but each moving target is blurred to different extents. Therefore, moving targets can be indicated by the patch-by-patch sharpness comparison of the two defocused images. The results of the simulated and real data show that this algorithm is effective and efficient.

Phase coherence factor for mitigation of sidelobe artifacts in through-the-wall radar imaging

Abstract: The phase coherence factor (PCF) is revised according to stepped frequency signal imaging radar, adding additional phase diversity in frequency domain. Then, it is applied to through-the-wall moving target indication processing for side and grating lobe artifacts mitigation. Experimental results show that PCF weighting approach can suppress both side and grating lobe artifacts effectively for through-the-wall images.

An effective CLEAN algorithm for interference cancellation and weak target detection in passive radar

Abstract: In passive radar which exploits opportunity source as the illuminator, the presence of direct signal and clutter echoes in surveillance channel is demonstrated strongly affecting the detection performance. In this paper, based on the well-known CLEAN approach which iteratively removes strong signal and detects targets, an effective CLEAN algorithm is derived for interference cancellation. The new technique adopts the method of orthogonal subspace projection and is more robust even under the following cases: (i) The arrival time of interference signals may be fractional sampling interval after sampling; (ii) The Doppler-delay estimation of interference may be inaccuracy; (iii) The echoes from continuous scattering targets may be Dopplerdelay spread. The approach is shown to be effective through simulation results which considers digital video broadcasting satellites (DVB-S) as the illuminator.

Multichannel synthetic aperture radar signatures and imaging of a moving target

Abstract: An airborne multichannel synthetic aperture radar imaging process is analyzed to derive spatial image and spectral signatures of a point target moving at a constant velocity. These signatures are expressed in terms of the moving target focal position that changes with the antenna array element location and the relative target-to-radar velocity vector and, as a result, the geometric transformation between two coordinate frames. One frame is stationary while the other moves with the target. The resulting target image spectrum is used to formulate a moving target image refocusing algorithm and a calibration approach useful to compensate the image modulation due to the directional antenna pattern effects. The potential applications of the multichannel signatures to target motion estimation and adaptive image processing will be explored.

Compressive sensing-based ground moving target indication for dual-channel synthetic aperture radar

Abstract: Multi-channel synthetic aperture radar (SAR) system has excellent performance of main-lobe clutter suppression. However, the resulting enormous amount of sampling raw data increases storage and transmission load. To alleviate such payloads, the authors propose a SAR/ground moving target indication (GMTI) method using compressive sensing (CS) with a very limited number of echo samples, based on the fact that the moving targets are usually sparse although clutter scattering centres are non-sparse in most cases. In the proposed method, dual channel SAR data are sampled sparsely in the azimuth direction and jointly processed. Firstly, a transform matrix is constructed to separate the energy support areas of moving targets from that of all scattering centres. Then, the authors can roughly obtain the energy support areas of all scattering centres via CS. Finally, based on the acquired energy support areas above, GMTI is achieved by solving a weighted l 1 optimisation problem. Simulated and real data experiments demonstrate that the proposed method performs well with reduced sampled raw data, even if clutter scattering centres have a low-sparse level.

High-Accuracy Measurement of Small Movement of an Object behind Cloth Using Airborne Ultrasound

Abstract: The acoustic measurement of vital information such as breathing and heartbeat in the standing position whilst the subject is wearing clothes is a difficult problem. In this paper, we present the basic experimental results to measure small movement of an object behind cloth. We measured acoustic characteristics of various types of cloth to obtain the transmission loss through cloth. To observe the relationship between measurement error and target speed under a low signal-to-noise ratio (SNR), we tried to measure the movement of an object behind cloth. The target was placed apart from the cloth to separate the target reflection from the cloth reflection. We found that a small movement of less than 6 mm/s could be observed using the M-sequence, moving target indicator (MTI) filter, and tracking phase difference, when the SNR was less than 0 dB. We also present the results of theoretical error analysis in the MTI filter and phase tracking for high-accuracy measurement. Characteristics of the systematic error were clarified.

Airborne behaviour monitoring using Gaussian processes with map information

Abstract: This study proposes an airborne behaviour monitoring methodology of ground vehicles based on a statistical learning approach with domain knowledge given by road map information. To monitor and track the moving ground target using unmanned aerial vehicle aboard a moving target indicator, an interactive multiple model (IMM) filter is firstly applied. The IMM filter consists of an on-road moving mode using a road-constrained filter and an off-road moving mode using a conventional filter. Mode probability is also calculated from the IMM filter, and it provides deviation of the vehicle from the road. Then, a novel hybrid algorithm for anomalous behaviour recognition is developed using a Gaussian process regression on velocity profile along the one-dimensionalised position of the vehicle, as well as the deviation of the vehicle. To verify the feasibility and benefits of the proposed approach, a numerical simulation is performed using realistic car trajectory data in a city traffic.

Wideswath synthetic aperture radar ground moving targets indication with low data rate based on compressed sensing

Abstract: Wideswath synthetic aperture radar/ground moving targets indication (SAR/GMTI) system increases severely data transmission and storage load. To mitigate this problem, a wideswath GMTI method based on compressed sensing (CS) is proposed. In this method, CS is utilised to process each SAR data sampled sparsely in the azimuth direction for multiple aperture systems after conventional range compression. Then the wavelet transform matrix is used to construct the sparse matrix. Each SAR image is unambiguously achieved by solving l 1 norm optimisation problem in the azimuth. The clutter rejection is performed for all spatial SAR images and then moving targets can be well detected. In this way, the data rate together with storage load is reduced, and then the wideswath GMTI can be efficiently realised. Results of real measured and simulated SAR data processing demonstrate the effectiveness of the CS-based wideswath GMTI.

Modeling and simulation for multistatic coherent MIMO radar

Abstract: Multiple input multiple output (MIMO) radar systems employ multiple transmit and receive elements with transmit elements that have the ability to transmit arbitrary waveforms simultaneously and receive elements that have the ability to process all of the transmitted signals jointly. For ground moving target indication (GMTI) systems, MIMO offers the potential to improve angular resolution and illumination time of the radar and therefore lower the minimum detectable velocity of moving targets. In this paper, we consider GMTI systems consisting of airborne platforms in configurations which include collocated transmit and receive elements on a single platform, distributed transmit/receive elements using multiple platforms, and hybrid arrangements. A multistatic coherent MIMO GMTI model is formulated that consists of multiple spatially distributed, moving, multi-element transmit and receive platforms that form multiple bistatic coherent MIMO pairs. Optimum and adaptive detectors are developed and performance is evaluated via simulation for the multistatic coherent MIMO system as well as each bistatic coherent MIMO pair. A clutter simulation methodology is presented that combines a realistic physics-based bistatic scattering model with a spherically invariant random vector (SIRV) random sample generator.

Joint STAP-ISAR for non-cooperative target imaging in strong clutter

Abstract: The aim of this work is to combine clutter suppression and ISAR processing in order to obtain well focused images of extended moving targets. A STAP ISAR based moving target imaging scheme for Multichannel SAR (M-SAR) in strong clutter environment is presented. This scheme consists of two main processing steps. The first step performs clutter mitigation and radar motion compensation by exploiting Space Time Adaptive Processing while the second step performs target motion compensation using ISAR processing. Two principal issues will be addressed. First a technique for applying ISAR processing after clutter mitigation is presented and then a suboptimal approach to clutter mitigation is proposed to overcome computational and statistical issues associated with estimation of clutter space time covariance matrix. Results of the processing applied to simulated data are provided in order to show the effectiveness of the proposed technique.

Signal modeling for the efficient target detection tasks

Abstract: The statistical simulation systems which are created for the efficient solving of target detection tasks need to have special signal simulation complex. The simulation methods that can be used as the base of such complex for the pulse radar signals and clutters simulation are considered. The system that uses such algorithms is realized and demonstrates the efficiency of described methods.

Robust PCA for Ground Moving Target Indication in Wide-Area Surveillance Radar System

Abstract: Robust PCA has found important applications in many areas, such as video surveillance, face recognition, latent semantic indexing and so on. In this paper, we study its application in ground moving target indication (GMTI) in wide-area surveillance radar system. MTI is the key task in wide-area surveillance radar system. Due to its great importance in future reconnaissance systems, it attracts great interest from scientists. In (Yan et al. in IEEE Geosci. Remote Sens. Lett., 10:617–621, 2013), the authors first introduced robust PCA to model the GMTI problem, and demonstrate promising simulation results to verify the advantages over other models. However, the robust PCA model can not fully describe the problem. As pointed out in (Yan et al. in IEEE Geosci. Remote Sens. Lett., 10:617–621, 2013), due to the special structure of the sparse matrix (which includes the moving target information), there will be difficulties for the exact extraction of moving targets. This motivates our work in this paper where we will detail the GMTI problem, explore the mathematical properties and discuss how to set up better models to solve the problem. We propose two models, the structured RPCA model and the row-modulus RPCA model, both of which will better fit the problem and take more use of the special structure of the sparse matrix. Simulation results confirm the improvement of the proposed models over the one in (Yan et al. in IEEE Geosci. Remote Sens. Lett., 10:617–621, 2013).

Method of measuring Doppler shift of moving targets using FMCW maritime radar

Abstract: During the operation of an FMCW (frequency modulated continuous wave) maritime radar, the system transmits a continuous radio energy with a frequency modulated by a triangular or sawtooth-shaped signal. As a result, the frequency of the transmitted signal varies gradually with time. When the signal is reflected by an object, the received waveform will build up a delayed replica of the transmitted waveform, with the time delay as a measure of the target range. If the target is moving, the radar system will register a Doppler shift within the received signal. Compared to the frequency of the emitted signal, the received signal will show a higher frequency when the target is approaching and a lower frequency when the target is moving away from the radar location. Thus, the total Doppler shift may result from the superposition of both source and observer motions. Specifically, the amount of Doppler shift is directly proportional to the radial speed of the target. The Doppler shift can be determined after performing the range Fourier transform (range FFT) first. For a target of interest, we can repeat the range FFT until we have enough data to perform the second level of FFT. The result of this second FFT is a two dimensional complex valued matrix, whose spectral peak corresponds to the Doppler shift of the moving target. This method is known as Doppler FFT. Some results of the measurement of target speed using this method are presented in this paper.

An experimental study on image based multi-channel SAR-GMTI algorithm

Abstract: The authors have recently proposed an algorithm for target detection and velocity estimation for multi-channel SAR-GMTI (Synthetic Aperture Radar - Ground Moving Target Indication) systems [1]. The proposed algorithm is a combination of extensions of DPCA (Displaced Phase Center Antenna) and ATI (Along Track Interferometry). In this paper, we report some results obtained from an airborne three-channel SAR experiment to show the potentials of the proposed algorithms.

An Investigation into Ground Moving Target Indication (GMTI) Using a Single-Channel Synthetic Aperture Radar (SAR)

Abstract: An Investigation into Ground Moving Target Indication (GMTI) Using a Single-Channel Synthetic Aperture Radar (SAR) Joseph W. Winkler Department of Electrical and Computer Engineering, BYU Master of Science Synthetic aperture radar (SAR) was originally designed as an airborne ground-imaging radar technology. But it has long been desired to also be able to use SAR imaging systems to detect, locate, and track moving ground targets, a process called Ground Moving Target Indication (GMTI). Unfortunately, due to the nature of how SAR works, it is inherently poorly suited to the task of GMTI. SAR only focuses targets and image features that remain stationary during the data collection. A moving ground target therefore does not focus in a conventional SAR image, which complicates the process of performing GMTI with SAR systems. This thesis investigates the feasibility of performing GMTI with single-channel, unsquinted, broadside stripmap SAR despite this inherent limitation. This study focuses solely on the idealized case of direct energy returns from point targets on flat ground, where they and the airborne radar platform all move rectilinearly with constant speed. First, the various aspects of how SAR works, the signal processing used to collect the SAR data, and the backprojection image formation algorithm are explained. The effects of target motion are described and illustrated in actual and simulated SAR images. It is shown how the backprojection (BPJ) algorithm, typically used to image a stationary landscape scene, can also focus on moving targets when the target motion is known a priori. A SAR BPJ ambiguity function is also derived and presented. Next, the time-changing geometry between the airborne radar and a ground target is mathematically analyzed, and it is shown that the slant range between the radar and any ground target, moving or stationary, is a hyperbolic function of time. It is then shown that this hyperbolic range history causes the single-channel SAR GMTI problem to be underdetermined. Finally, a method is then presented for resolving the underdetermined nature of the problem. This is done by constraining a target’s GMTI solution using contextual information in the SAR image. Using constraining information, a theoretical way is presented to perform limited GMTI with a single-channel SAR system by using a modified form of the BPJ imaging algorithm, and practical considerations are addressed that complicate the process. Instead of focusing on stationary pixels, this GMTI method uses the BPJ ambiguity function to search for moving targets on a straight path, such as a road, by performing matched filtering on a collection of moving pixels in a position-velocity image space. Nevertheless, it is concluded that for moving point targets, general GMTI with no path constraints is infeasible in practice with a single-channel SAR.

Method for suppressing multipath clutters of through-the-wall radar

Abstract: The invention relates to a method for suppressing multipath clutters of a through-wall radar, and belongs to the technical field of through-wall radars. Firstly a moving target indicator (MTI) is adopted to filter and suppress strong static clutters including wall back waves and the like, the back waves of moving objects are protruded, and detection of cell average-constant false alarm rate (CA-CFAR) is carried out; secondly range delay information of detected real objects and the multipath clutters is cohesively extracted in the distance direction; then corresponding range delay of multipath channels is forecast by adoption of wall position information and detected object distance delay; and finally, detected objects are separated through the range of distance delay of the detected multipath channels, and the multipath clutters are screened and suppressed. Based on a single-shot single-receiving antenna allocation, back wave data of the through-wall radar are detected, the distance information of the moving objects is extracted, meanwhile interference with a radar system by the multipath clutters is suppressed, detecting performance of the radar system can be improved significantly, and impact on the radar system by the multipath clutters is suppressed.

Clutter reduction based on coefficient of variation in through-wall radar imaging

Abstract: In this paper, the coefficient of variation (CV), defined as the ratio of the standard deviation to the mean in statistics, is applied to through-wall imaging for clutter reduction. The received signals coming from a given point in the imaging scene are taken as the statistical samples of its corresponding pixel in the image. Then the CVs in three classes of pixels are examined: the target pixel, the clutter pixel, and the noise pixel. It could be observed that the CV in target pixel is much smaller than that in clutter pixel as well as in noise pixel. Taking advantage of this, each pixel in the image is weighted by the reciprocal of its CV. The corrected image shows that this approach can highlight the target pixels by suppressing the clutter and noise pixels. The effectiveness of this approach is validated using both simulation and real data.

Performances analysis of moving target tracking in circular SAR

Abstract: Ground moving target focusing and tracking using airborne data is a subject of increasing interest. Single antenna processing allows focusing [1] and azimuthal velocity estimation [2][3] under the assumption that the signal-to-clutter ratio (SCR) is high enough (for instance, 14dB in [3]), which is mostly not the case in an urban context. Moreover, these methods are insufficient to geolocalize the moving targets. Acquisition of SAR data over a circular path eliminates this drawback, because objects may be seen at a 360° angle during a longer time than in the case of linear path. A technique to track moving targets in SAR images with only one sensor and using a circular path has been presented in [4]. In this paper, we perform a physical and geometrical analysis of this method and present accuracy evaluations. Finally some new results are presented on real data acquired around the city of Nimes (X band).

Radar detection for non-stationary time-Doppler signal based on Fréchet distance of geodesic curves on covariance matrix information geometry manifold

Abstract: New challenge in Radar is the processing of non-stationary signal corresponding to fast time variation of Doppler Spectrum in one burst. We can observe this phenomenon for high speed or abrupt Doppler variations of clutter or target signal but also in case of target migration during the burst duration due to high range resolution. We will assume that each non-stationary target signal in one burst can be split into several short signals with less Doppler resolution but stationary, represented by time sequence of stationary covariance matrices or a geodesic polygon on covariance matrix manifold. For micro-Doppler analysis of these cases, we adapt the Frechet distance between two curves in the plane with a natural extension to more general geodesic curves in abstract metric spaces used for covariance matrix manifold. This new approach could be used for robust detection of target with non-stationary Time-Doppler spectrum (NS-OS-HDR-CFAR: Non-Stationary Ordered Statistic High Doppler Resolution CFAR), False Alarm filtering for inhomogeneous clutter (statistics of plots Time-Doppler fluctuation), but also emerging civil applications like wind-shear, micro-burst, downdraft and wake-vortex detection.

Application of Detection and Recognition Algorithms to Persistent Wide Area Surveillance

Abstract: The persistent airborne surveillance of large geographical areas is now a viable proposition. As well as providing cues to moving objects, it presents new opportunities for understanding the behaviours and motivations of people, both individually and collectively. Exploitation of these huge collections of imagery (a facet of the Big Data challenge) requires more effective tools to derive and abstract useful information to cue the analyst. This paper describes a new system which brings together a number of techniques: moving target detection; tracking; recognition and photogrammetry, to address wide area surveillance problems. We provide a first report on the demands this places on component parts and interfaces. Significantly, we adopt international interoperability standards, particularly with regard to video metadata, to constrain the solution space. We also describe new performance improvements to the video moving target indication and photogrammetry algorithms as well as analysing for the first time the performance of our integrated target model matching capability in our automated system.

Learning-based space-time adaptive processing

Abstract: Space-time adaptive processing (STAP) has been used for many years in moving target indicator (MTI) radars to solve the problem of target detection in presence of an interfering environment. Over the years, different versions of STAP have been introduced to enhance its performance and overcome its practical difficulties. In this work, we introduce a new method for target detection and localization in which the need for a large homogenous target-free set of training range bins - which is traditionally used to estimate the interference covariance matrix - is reduced by the use of regression methods and pattern classification techniques to train over the 2D spatial-temporal space. It is shown that the proposed Learning-Based Space-Time Adaptive Processing (LBSTAP) technique not only reduces the need for a large, usually unavailable, homogenous target-free set of range bins, but also provides better performance in terms of Doppler side-lobe-level reduction.

On-demand simultaneous synthetic aperture radar (sar) and ground moving target indication (gmti) using mobile devices

Abstract: Methods and apparatus are provided for obtaining current geographic imagery and moving target geolocations and tracks from a typically autonomous remote platform device with sensors spanning the electromagnetic spectrum through a mobile device interface. An autonomous system is provided capable of interpreting high-level commands, measuring data using multiple sensors and processing the data to generate relevant data products which expedites the data measurement/processing procedure enabling field personnel to request and receive mission-critical intelligence in a timely manner.

Riemannian mean and space-time adaptive processing using projection and inversion algorithms

Abstract: The estimation of the covariance matrix from real data is required in the application of space-time adaptive processing (STAP) to an airborne ground moving target indication (GMTI) radar. A natural approach to estimation of the covariance matrix that is based on the information geometry has been proposed. In this paper, the output of the Riemannian mean is used in inversion and projection algorithms. It is found that the projection class of algorithms can yield very significant gains, even when the gains due to inversion-based algorithms are marginal over standard algorithms. The performance of the projection class of algorithms does not appear to be overly sensitive to the projected subspace dimension.