Showing papers on "Moving target indication published in 2008"

MIMO Radar Signal Processing

Abstract: PREFACE. CONTRIBUTORS. 1 MIMO Radar - Diversity Means Superiority (Jian Li and Petre Stoica). 1.1 Introduction. 1.2 Problem Formulation. 1.3 Parameter Identifiability. 1.4 Nonparametric Adaptive Techniques for Parameter Estimation. 1.5 Parametric Techniques for Parameter Estimation. 1.6 Transmit Beampattern Designs. 1.7 Conclusions. Appendix IA Generalized Likelihood Ratio Test. Appendix 1B Lemma and Proof. Acknowledgments. References. 2 MIMO Radar: Concepts, Performance Enhancements, and Applications (Keith W. Forsythe and Daniel W. Bliss). 2.1 Introduction. 2.2 Notation. 2.3 MIMO Radar Virtual Aperture. 2.4 MIMO Radar in Clutter-Free Environments. 2.5 Optimality of MIMO Radar for Detection. 2.6 MIMO Radar with Moving Targets in Clutter: GMTI Radars. 2.7 Summary. Appendix 2A A Localization Principle. Appendix 2B Bounds on R(N). Appendix 2C An Operator Norm Inequality. Appendix 2D Negligible Terms. Appendix 2E Bound on Eigenvalues. Appendix 2F Some Inner Products. Appendix 2G An Invariant Inner Product. Appendix 2H Kronecker and Tensor Products. Acknowledgments. References. 3 Generalized MIMO Radar Ambiguity Functions (Geoffrey San Antonio, Daniel R. Fuhrmann, and Frank C. Robey). 3.1 Introduction. 3.2 Background. 3.3 MIMO Signal Model. 3.4 MIMO Parametric Channel Model. 3.5 MIMO Ambiguity Function. 3.6 Results and Examples. 3.7 Conclusion. References. 4 Performance Bounds and Techniques for Target Localization Using MIMO Radars (Joseph Tabrikian). 4.1 Introduction. 4.2 Problem Formulation. 4.3 Properties. 4.4 Target Localization. 4.5 Performance Lower Bound for Target Localization. 4.6 Simulation Results. 4.7 Discussion and Conclusions. Appendix 4A Log-Likelihood Derivation. Appendix 4B Transmit-Receive Pattern Derivation. Appendix 4C Fisher Information Matrix Derivation. References. 5 Adaptive Signal Design For MIMO Radars (Benjamin Friedlander). 5.1 Introduction. 5.2 Problem Formulation. 5.3 Estimation. 5.4 Detection. 5.5 MIMO Radar and Phased Arrays. Appendix 5A Theoretical SINR Calculation. References. 6 MIMO Radar Spacetime Adaptive Processing and Signal Design (Chun-Yang Chen and P. P. Vaidyanathan). 6.1 Introduction. 6.2 The Virtual Array Concept. 6.3 Spacetime Adaptive Processing in MIMO Radar. 6.4 Clutter Subspace in MIMO Radar. 6.5 New STAP Method for MIMO Radar. 6.6 Numerical Examples. 6.7 Signal Design of the STAP Radar System. 6.8 Conclusions. Acknowledgments. References. 7 Slow-Time MIMO SpaceTime Adaptive Processing (Vito F. Mecca, Dinesh Ramakrishnan, Frank C. Robey, and Jeffrey L. Krolik). 7.1 Introduction. 7.2 SIMO Radar Modeling and Processing. 7.3 Slow-Time MIMO Radar Modeling. 7.4 Slow-Time MIMO Radar Processing. 7.5 OTHr Propagation and Clutter Model. 7.6 Simulations Examples. 7.7 Conclusion. Acknowledgment. References. 8 MIMO as a Distributed Radar System (H. D. Griffiths, C. J. Baker, P. F. Sammartino, and M. Rangaswamy). 8.1 Introduction. 8.2 Systems. 8.3 Performance. 8.4 Conclusions. Acknowledgment. References. 9 Concepts and Applications of A MIMO Radar System with Widely Separated Antennas (Hana Godrich, Alexander M. Haimovich, and Rick S. Blum). 9.1 Background. 9.2 MIMO Radar Concept. 9.3 NonCoherent MIMO Radar Applications. 9.4 Coherent MIMO Radar Applications. 9.5 Chapter Summary. Appendix 9A Deriving the FIM. Appendix 9B Deriving the CRLB on the Location Estimate Error. Appendix 9C MLE of Time Delays - Error Statistics. Appendix 9D Deriving the Lowest GDOP for Special Cases. Acknowledgments. References. 10 SpaceTime Coding for MIMO Radar (Antonio De Maio and Marco Lops). 10.1 Introduction. 10.2 System Model. 10.3 Detection In MIMO Radars. 10.4 Spacetime Code Design. 10.5 The Interplay Between STC and Detection Performance. 10.6 Numerical Results. 10.7 Adaptive Implementation. 10.8 Conclusions. Acknowledgment. References. INDEX.

4D GIS based virtual reality for moving target prediction

Abstract: The technology of the 4D-GIS system deploys a GIS-based algorithm used to determine the location of a moving target through registering the terrain image obtained from a Moving Target Indication (MTI) sensor or small Unmanned Aerial Vehicle (UAV) camera with the digital map from GIS. For motion prediction the target state is estimated using an Extended Kalman Filter (EKF). In order to enhance the prediction of the moving target's trajectory a fuzzy logic reasoning algorithm is used to estimate the destination of a moving target through synthesizing data from GIS, target statistics, tactics and other past experience derived information, such as, likely moving direction of targets in correlation with the nature of the terrain and surmised mission.

Wide-Area Traffic Monitoring With the SAR/GMTI System PAMIR

Abstract: This paper presents a wide area traffic monitoring experiment under real conditions, using the scan-MTI mode of the airborne radar sensor PAMIR. This flexible GMTI (Ground Moving Target Indication) mode was designed in order to rapidly monitor wide areas for moving targets. The scan operation enables the detection of targets from different aspect angles with a high revisit rate. The parameters (e.g., radial velocity, signal-to-noise ratio, and positioning accuracy) of the detected vehicles are investigated and compared to the expected theoretical GMTI performance. It will be shown that the scan-MTI mode is particularly adapted to perform an efficient wide-area traffic monitoring.

Improved Space-Based Moving Target Indication via Alternate Transmission and Receiver Switching

Abstract: Ground moving target indication (GMTI) by space-based radar systems requires special antenna and data acquisition concepts to overcome the problem of discriminating target signals from clutter returns. Owing to the high satellite speed, the clutter contains a broad mixture of radial velocities within the antenna beam, leading to a large Doppler spread. Effective clutter suppression can solely be achieved by multiple aperture or phase center antennas. For space-based systems, however, the number of receiver channels connected to subapertures is very limited due to their weight, volume, and high data rates (current systems such as TerraSAR-X and RADARSAT-2 possess only two). This classical along-track interferometry architecture, in which the antenna is split into two halves, achieves only suboptimum GMTI performance. This paper presents and statistically analyzes an innovative approach to create additional independent phase centers to improve the GMTI performance considerably. The extra degrees of freedom are created by cyclical phase and amplitude switchings of the transmit/receive modules for transmitter and receiver between pulses, hence trading Doppler bandwidth for extra spatial diversity. In the first part of this paper, different strategies of spatial-temporal diversity are introduced and analyzed for realistic system parameters with respect to ambiguities and detection performance. The second part is concerned with the elaborate theoretical analysis of the relocation improvement for the spatial diversity approach.

An approach to remove the clutter and detect the target for ultra-wideband through-wall imaging

Abstract: Through-wall imaging (TWI) is important from the point of view of rescue operations and surveillance. Several researchers have been working in this field but have still not obtained any concrete results. TWI using narrow band radar faces the problem of low resolution whereas ultra-wideband (UWB) radar provides better resolution, classification and low loss for the imaging signals. TWI faces many challenges in collecting the scattered electromagnetic fields from objects located behind the wall and also in processing the data in order to detect, locate and image the object. One of the important factors for achieving a high-quality image is to use clutter reduction techniques so that clutter as well as false target detection can be minimized. Therefore, in this paper, an attempt has been made to develop a clutter reduction technique for TWI in the UWB range for target detection. For this purpose, an experiment has been carried out with a TWI system in the UWB range for determination of the target position and size along with the development of the signal processing technique to minimize the clutter. A singular value decomposition (SVD) algorithm has been applied for clutter reduction. Encouraging results have been obtained from a metallic target behind a plywood wall of thickness 12 mm and a brick wall of thickness 110 mm. Application of the SVD approach provides a powerful technique for minimizing clutter and false detection for the TWI system in the UWB range. The position of the target behind the wall is predicted quite accurately by taking into account the propagation speed of waves through-walls. The approximate size of the target is also predicted successfully.

Ground Moving Target Indication With Tandem Satellite Constellations

Abstract: Ground moving target indication (GMTI) from space by existing dual-channel radar systems such as TerraSAR-X and RADARSAT-2 has been shown to perform only insufficiently with respect to the relocation error of targets to their true ground position. Only two parallel receiver channels are too little to suppress the severe ground clutter and to estimate the target's parameters. Although this deficiency may partly be alleviated through antenna aperture switching, the resulting positioning accuracy is still not adequate for effective traffic monitoring purposes. Satisfactory results are only achievable with extended apertures, primarily with satellite constellations. This letter presents a statistical analysis of the performance of different concepts for cooperating back-to-back flying satellite systems. Particularly in anticipation of TanDEM-X, which will form the first operational GMTI-capable coherent synthetic aperture radar constellation after its launch in 2009.

Parametric Velocity Synthetic Aperture Radar:Signal Modeling and Optimal Methods

Abstract: Velocity synthetic aperture radar (VSAR) is equipped with a linear array to receive the echoes from a radar illuminating area via multiple channels, each of which can reconstruct a reflectivity image for the same stationary scene. Based on analysis of pixel vector sampled among multi-images, VSAR may effectively suppress the strong ground clutter and improve moving target detection and location. In this paper, different Doppler-distributed properties are derived for the moving target and clutter, respectively. Then, we propose a novel parametric statistical model for VSAR by dividing the pixel vector into three components, namely, target, clutter, and noise. Furthermore, a method of adaptive implementation of optimal processing (AIOP-VSAR) is presented for moving target detection. It is shown that the optimum detection performance may be obtained via AIOP-VSAR, particularly for the slowly moving target in an inhomogeneous clutter environment. Also, the Cramer-Rao bounds (CRBs) are derived for the estimation of unknown model parameters, as well as the azimuth locations of moving targets, and the maximum-likelihood methods are proposed to reach these CRBs. Based on the proposed target detection and parameter estimation methods, we present a complete parametric flowchart for VSAR. It is demonstrated that the proposed flowchart may effectively mitigate the "azimuth location ambiguity" of VSAR and has the super-resolution ability to resolve "velocity layover" for multiple targets. Finally, some detailed numerical experiments and scene simulations are provided to show the effectiveness of the proposed methods.

Time-Frequency Analysis for the Localization of Multiple Moving Targets Using Dual-Frequency Radars

Abstract: A dual-frequency radar, which estimates the range of a target based on the phase difference between two closely spaced frequencies, has been shown to be a cost-effective approach to accomplish both range-to-motion estimation and tracking. This approach, however, suffers from two drawbacks: it cannot deal with multiple moving targets, and it has poor performance in noisy environments. In this letter, we propose the use of time-frequency signal representations to overcome these drawbacks. The phase, and subsequently the range information, is obtained based on the moving target instantaneous Doppler frequency law, which is provided through time-frequency signal representations. The case of multiple moving targets is handled by separating the different Doppler signatures prior to phase estimation.

Along-track interferometry for ground moving target indication

Abstract: Synthetic aperture radar (SAR) along-track interferometry (ATI) has been used extensively to measure ocean surface currents. Given its ability to measure small velocities (-10 cm/s) of relatively radar-dark water surfaces, there is great potential that this technique can be adapted for ground moving target indication (GMTI) applications, particularly as a method for detecting very slow targets with small radar cross-sections. Herein, we describe preliminary results from an ATI GMTI experiment. The SAR data described were collected by the dual-frequency NASA/JPL airborne radar in its standard dual-baseline ATI mode. The radar system imaged a variety of control targets including a pickup truck, sport utility vehicles, passenger cars, a bicycle, and pedestrians over multiple flight passes. The control targets had horizontal velocities of less than 5 m/s. The cross-sections of the targets were not purposely enhanced, although the targets' reflectivities may have been affected by the existence of the GPS equipment used to record the targets' positions. Single-look and multiple-look interferograms processed to the full azimuth resolution were analyzed. In the data processed to date, all of the targets were observed by visual inspection in at least one of the four combinations of dual-frequency, dual-baseline interferometric data. This extremely promising result demonstrates the potential of ATI for GMTI applications.

Ground Moving Target Indication Using an InSAR System With a Hybrid Baseline

Abstract: In this letter, a two-channel airborne experimental interferometric synthetic aperture radar (InSAR) designed for terrain height estimation is exploited to acquire the ability of ground moving target indication (GMTI). Due to the hybrid baseline of this system, the interferometric phase changes with the target motion as well as the terrain height. The fluctuation of the interferometric phase worsens the performance of the clutter suppression and the radial velocity estimation. In order to resolve this problem, a GMTI method with three steps is proposed. After two steps are used to eliminate the local flat-Earth phase and the cross-track interferometric phase of the scene, respectively, an adaptive filtering method is used to suppress the stationary clutter with the benefit of calibrating the sensor responses. A conventional constant false alarm rate detector is then used to indicate the moving targets. The validity of the proposed method is demonstrated with real data collected using an experimental airborne InSAR system.

Dismount modeling and detection from small aperture moving radar platforms

Abstract: Future advanced radar systems must detect targets of diminishing radar cross section (RCS) at low radial velocity, in demanding clutter and interference environments. Presently, a deficiency in radar detection performance exists between the capabilities of synthetic aperture radar (SAR) for fixed target indication and space-time adaptive processing (STAP) for ground moving target indication (GMTI) of targets with low ground track velocity. Dismounts, individuals or groups running, walking, or crawling, constitute a class of targets that falls into this netherworld between SAR and STAP. While possessing low RCS levels and radial velocities, dismount detection is rendered even more challenging due to their complicated non-linear phase histories that give rise to significant micro-Doppler energies. In this paper we develop a physiological human-gait model for multi-channel moving radar platforms. We characterize the dismount detection performance of a notational UAV system using linear phase, quadratic phase and sinusoidal phase filters. Finally, we summarize our results and present areas of future work.

Tracking systems

Abstract: The tutorial is an overview of tracking and data fusion for surveillance systems with applications both to defense and civilian systems. It is divided into four parts: Part 1 - Filtering: Covers the topics related to state estimation for stochastic dynamic systems: optimal Bayesian estimator, Kalman filter, nonlinear filters (extended and unscented Kalman filter, Gaussian sum filter, particle filter); filters for maneuvering motion (Interactive multiple-model filter); Crame-Rao lower bounds for filtering. Part 2 - Data association: Due to the imperfections of a detector, the input to a tracking system may lack the target originated detections and often contains false detections (due to clutter). The data association component of a tracking system determines the origin of each input detection. The tutorial will cover techniques such as: gating, (global) nearest neighbor algorithm, (joint) probabilistic data association, multiple hypotheses tracking. In addition, the idea of using random sets for multi-target tracking will be introduced with a review of the PHD filter. Part 3 - Distributed multi-sensor tracking: Modern surveillance systems typically consist of multiple sensors connected by a communication network for a data exchange. While the network surveillance offers potentially more accurate and reliable performance, there are many practical issues that need to be resolved beforehand. The tutorial will provide answers to problems: how to choose the multi-sensor architecture, how to avoid a repeated use of the same information, how to perform distributed track association and track fusion, how to ensure proper multi-sensor alignment in time and space. Part 4 - Selected applications: The last part of the tutorial will cover several practical applications: ballistic missile tracking, GMTI radar tracking, tracking with hard constraints, angle-only tracking, tracking using TDoA measurements, track-before-detect, video tracking, tracking using an acoustic sensor network, etc.

Improvement of Multiple Ground Targets Tracking with GMTI Sensor and Fusion of Identification Attributes

Abstract: Multiple ground targets (MGT) tracking is a challenging problem in real environment because of partial observations, high traffic density, the maneuverability of targets, the clutter and the low target detection probabilities. Most of current MGT trackers use GMTI (Ground Moving Target Indicator) sensor, since this sensor provides the range- rate measurement (Doppler) aside classical position measurements. This helps the tracking algorithms and the preliminary ground target classification. Advanced algorithms include exogeneous information like road network and terrain topography. In this paper, we develop a new improved VS-IMM (Variable Structure Interacting Multiple Model) algorithm for GMTI tracking which includes the stop-move target maneuvering model, contextual information (on-off road model, road network constraints), and identification information arising from classifiers coupled with the GMTI sensor. The identification information is integrated to the likelihood of each hypothesis of our SB-MHT and allows to solve efficiently most of ambiguities that can arise mainly at road intersections or after a target maneuver when leaving the road, or with undetected ground targets after few scans. We maintain aside each target track a set of ID hypotheses with their committed beliefs which are updated on real time with classifier decisions through target type tracker based on a proportional conflict redistribution fusion rule. The advantage of such a new approach is to deal precisely and efficiently with the identification attribute information available as it comes by taking into account its inherent uncertainty/non-specificity and possible high auto-conflict.

Recent MTI experiments using ARL's synchronous impulse reconstruction (SIRE) radar

Abstract: The Army Research Laboratory (ARL) has recently developed the ground-based synchronous impulse reconstruction (SIRE) radar - a low-frequency radar capable of exploiting both a real antenna array and along-track integration techniques to increase the quality of processed imagery. We have already demonstrated the system's utility by imaging static scenes. In this paper we address the moving target indication (MTI) problem, and we demonstrate the impulse-based system's ability to both detect and locate slowly moving targets. We begin by briefly describing the SIRE system itself as well as the system configuration utilized in collecting the MTI data. Next we discuss the signal processing techniques employed to create the final MTI image. Finally, we present processed imagery illustrating the utility of the proposed method.

Cluster tracking under kinematical constraints using random matrices

Abstract: Collectively moving object clusters are of particular interest in certain applications and have to be tracked as separate aggregated entities consisting of an unknown number of individuals. Tracking of convoys or large vehicles in wide area ground surveillance are practically important examples (GMTI: Ground Moving Target Indicator). In standard tracking algorithms, the objects of interest are usually considered as point source objects; i. e. compared to the sensor resolution their spatial extension is neglected. Due to the increasing resolution capabilities of modern sensors, however, different scattering centers of an extended object cam cause distinct detections. In this sense also collectively moving object groups can be considered as extended objects. Due to the resulting data association and resolution conflicts. any attempt of tracking individual objects within the group is no longer reasonable. In this paper ellipsoidal object extensions are modeled by random matrices, which are treated as additional state variables to be estimated. An important aspect is the incorporation of context information into the Bayesian data processing formalism. We here consider kinematical constraints such as road maps and sensor specific characteristics such as Doppler-blindness.

Microwave motion detectors utilizing multi-frequency ranging and target angle detection

Abstract: A method of detecting a moving target within a predefined protected region with a microwave motion detector, by transmitting microwave frequency signals and receiving the microwave frequency signals reflected by a target. A target distance is then determined from the received microwave frequency signals, and a target angle is determined from the received microwave frequency signals. Then, a target location is determined from the target distance and the target angle, and an alarm condition is set if the target location is within the predefined protected region.

Improving Coherence of Complex Image Pairs Obtained by Along-Track Bistatic SARs Using Range–Azimuth Prefiltering

Abstract: An along-track interferometric synthetic aperture radar (SAR) can be used for ground moving target indication (GMTI) by comparing two SAR images obtained at different observation times. Different geometries of the two observations bring the decorrelation noise, which will degrade the detection performance. For bistatic SARs, the decorrelation theory is quite different from that for monostatic ones. This paper deals with the coherence between two complex SAR images formed by two along-track bistatic SARs with different baseline lengths. Using the single scattering model, the coherence between the two echoes collected by the two receivers is investigated, and the full-coherence conditions are derived. Then, a new method based on range-azimuth prefiltering is proposed to improve the coherence of complex image pairs. As the precise prefiltering is complicated, its three approximate implementations are given. The effects of prefiltering on SAR images are also analyzed. Finally, simulation results validate the effectiveness of the proposed method.

Change detection based GMTI on single channel SAR images

Abstract: The focus of this paper is on the detection and velocity estimation of moving targets in single-channel SAR images. In particular, for detection purpose, a non coherent change detection technique is proposed and its theoretical performance is investigated. Concerning the velocity estimation, an analytical model relating the observed and real cross-range velocity is derived and used for those targets having radial motion. The theoretical performance analysis and the results obtained against real SAR data show the effectiveness of the proposed approach.

Along track interferometry for foliage penetration Moving Target Indication

Abstract: Moving target indication radars for detection and tracking ground vehicles has received significant interest in the radar literature. However, when the vehicles are moving slowly and in foliage, microwave frequency radars such as X-band are not effective. Foliage penetration (FOPEN) radars using ultra high frequency (UHF) synthetic aperture waveforms have demonstrated consistent detection of stationary ground vehicles. In most applications, the vehicles are stationary to support wide angle, high resolution SAR processing. Along track interferometry (ATI) has been proposed for space based radars to detect moving targets due to the high velocity of the radar. This study will examine the target and processing requirements to detect slowly moving ground vehicles using ATI approaches. A detailed simulation of the target and clutter phenomenology is carried out to illustrate the effects of internal clutter motion and signal decorrelation effects on minimum discernable velocity.

Ground Moving Target Tracking with context information and a refined sensor model

Abstract: For the detection of targets moving on ground, airborne ground moving target indicator (GMTI) radar is well-suited. In the tracking process, complex target dynamics, particularly stop and go maneuvers, and target masking due to Doppler blindness, often lead to track losses. By means of a refined sensor model it is possible to detect and handle such diverse target states. In addition, the generation of precise and continuous tracks from GMTI radar plots often is a demanding task due to terrain and technical obscuration and clutter. The exploitation of topographic background information such as road maps and terrain data is therefore highly desirable for the enhancement of track quality and track continuity. In the present paper these two aspects have been merged. The significant gain in track quality and track continuity is demonstrated in a number of simulation scenarios involving Doppler blindness and terrain obscuration.

Precision GMTI tracking using road constraints with visibility information and a refined sensor model

Abstract: For detecting targets moving on ground, airborne ground moving target indicator (GMTI) radar is well-suited due to its wide-area, all-weather, day/night, and real time capabilities. The generation of GMTI tracks from these data is the backbone for target identification, ground surveillance as well as traffic flow analysis. The generation of precise and continuous tracks from GMTI radar plots often is a demanding task due to terrain and technical obscuration and clutter. The exploitation of non-standard background information such as road maps and terrain information is therefore highly desirable for the enhancement of track quality and track continuity. The present paper presents a Bayesian tracking scheme that incorporates digital road-map information and a model for the clutter notch of the GMTI sensor. The significant gain in track quality and track continuity is demonstrated in a number of simulation scenarios involving Doppler blindness and terrain obscuration.

SAR Traffic Monitoring Using Time-Frequency Analysis for Detection and Parameter Estimation

Abstract: In the paper a ground moving target indication (GMTI) algorithm operating on preprocessed range-compressed SAR data is presented. For preprocessing range cell migration correction for stationary targets in most practical cases is sufficient. Moving target signal detection and extraction, adaptive range cell migration correction, position and across as well as along-track velocity estimation is then performed without a priori knowledge by using matched filter banks and the fractional Fourier transform. The proposed algorithm is able to cope with multi-component linear frequency modulated signals as they arise in real traffic scenarios containing a number of moving road vehicles.

A new deceptive jamming method for SAR based on false moving targets

Abstract: In SAR/GMTI, static jamming such as noise and deceptive scene will be eliminated as clutter, and will make no sense. In this paper, a deceptive jamming method for SAR is lucubrated to protect military moving targets. For false moving targets (FMT) consisting of many scattering centers, we propose an improved way to generate false signals. Through separating the response function of false signals into range-related and azimuth-related parts, the new method can reduce the algorithm complexity effectively. Moreover, the factors which will affect the jamming efficiency are analyzed. Simulation results show that the new method is effective to SAR/GMTI and the conclusions are valid.

Detecting and tracking of small moving target under the background of sea level

Abstract: Target detecting and tracking based on video is one of the significant research field of computer vision, in this paper some research has been done on the small moving target under the background of sea level. In the process of target detecting, the moving targets detecting algorithm combining the method of background subtraction with the method of symmetrical difference is proposed in this paper. In the process of target tracking, using mean shift combining Kalman filter. Kalman filter can predict the possible position on the next frame of the video image, and using the mean shift algorithm to search in this neighboring range, this method is effective on fast moving target. The experiment shows that itpsilas a good algorithm to track the small target in the circumstance of low signal noise rate.

Multistatic multihypothesis tracking: Environmentally adaptive and high-precision state estimates

Abstract: Multistatic active sonar has become an important surveillance concept. To fully exploit its benefits in a real-time and realistic scenario, a multihypotheses tracking (MHT) algorithm is proposed which as a extension from standard approaches allows high precision state estimation, treatment of multiple different types of sonar signals and allows adaptation to the highly instationary ocean environment. The algorithm is applied to two data sets gathered at sea trials conducted by NURC, and its performance is compared to the performance of the standard MHT approaches. In particular, the proposed treatment of the Doppler information, exploiting the Doppler notch of the reverberation, similarly to applications in moving target indication for ground surveillance, has led to a large performance gain.

Tracking of ground targets with bistatic airborne radar

Abstract: Detection of moving targets in stationary clutter can be accomplished by STAP radar. In contrast to monostatic radar the performance of bistatic STAP depends strongly on the actual radar-target geometry. Even for sidelooking radar the clutter Doppler is generally range dependent which causes special problems in estimating the space-time clutter covariance matrix. For certain bistatic constellations clutter notches as appearing during track (i.e. areas of low probability of detection) may be considerably wider than in monostatic radar. The bistatic transmitter-receiver constellation has strong implications on ground moving target tracking, which is basic for producing a recognized ground picture as well as for analyzing traffic flows, identifying sources and sinks of traffic, or detecting lines of communication. Aspects of a bistatic GMTI tracking algorithm are described and some typical tracking results are given. Special emphasis is placed on a suitable modeling of the bistatic radar characteristics within the tracker.

Spaceborne Interferometric and Multistatic SAR Systems

Abstract: This chapter analyses spaceborne multistatic imaging radar systems employing two or more receiver antennas on different platforms. The simultaneous data reception by multiple receivers enables a wealth of new synthetic aperture radar (SAR) imaging modes which evaluate the scattering signals from multiple view angles in combination. Potential application areas of multistatic SAR systems include, but are not limited to, single-pass cross-track and along-track interferometry, spaceborne tomography, wide swath SAR imaging, resolution enhancement, interference suppression, ground moving target indication (GMTI), and multistatic SAR imaging. Some of these applications can also be realized via multiple data acquisitions from repeat satellite passes. However, the simultaneous data acquisition with multiple satellites in a multistatic configuration avoids temporal decorrelation and atmospheric disturbances, improves the performance, and enables the detection of fast changes. This chapter gives a thorough overview of the capabilities and challenges associated with spaceborne interferometric and multistatic SAR missions. After a short introduction to interferometric SAR imaging, several design aspects are considered including phase and time synchronisation, formation and orbit selection, as well as the choice of suitable operational modes. The achievable performance is illustrated by the two mission examples TanDEM-X and TerraSAR-L cartwheel. An outlook on advanced multistatic SAR imaging modes illustrates their future potential for a wide range of remote sensing applications. The chapter is concluded with a discussion of major challenges to implement multistatic SAR missions in space.

Moving target detector

Abstract: PROBLEM TO BE SOLVED: To provide a moving target detector for detecting a moving target and estimating the speed thereof while suppressing degradation of the detection performance of the moving target. SOLUTION: This moving target detector includes data storage sections 1 and 2 for storing two received signals obtained using an antenna having an opening dividable in the moving direction of a platform, respectively, range compression processing sections 10A and 10B for compressing the received signals for two radar images stored in the data storage sections 1 and 2 in the distance directions, respectively, a moving target detection section 20 for detecting the moving target based on the data after two range compressions, and a target speed rough-estimation section 50 for estimating the target speed based on the distance to the antenna at each observation time of the detected moving target. COPYRIGHT: (C)2010,JPO&INPIT

PodSAR: A versatile real-time SAR GMTI surveillance and targeting system

Abstract: Synthetic aperture radar (SAR) and ground moving target indication (GMTI) systems from an airborne platform are in principle based on very simple concepts. The latter combines radar pulses over a short interval to extract Doppler information in order to detect ground moving targets against a clutter background. The former combines pulses over much longer intervals in a coherent manner to achieve very fine azimuth resolution. However, the many demands that are placed on such systems in terms of resolution, geolocation accuracy and coverage have led to the development of highly sophisticated algorithms. The ability to perform such complex processing in real-time on board the airborne radar platform presents significant computational challenges. This paper describes how a successful implementation of a real-time SAR GMTI system has been achieved with the QinetiQ PodSAR system. It describes the radar system that is mounted on a wide-bodied Andover aircraft. It discusses the design challenges that had to be overcome in order to achieve real-time processing for SAR and GMTI along with showing a number of examples of image exploitation techniques being developed using data from the PodSAR system.

An airborne radar system with adaptive MTD Doppler compensation scheme using DSP based real-time spectral estimation

Abstract: A scheme for the real-time estimation and compensation of the moving clutter Doppler shift due to the moving radar platform is presented for the airborne pulsed Doppler radar system. A new scheme employs the dwell-time based clutter-lock MTD method in order to estimate and compensate the mean Doppler shift within antenna beam dwell time by using high speed DSP based Doppler FFT processing. Through the helicopter-borne radar flight test using real-time radar data acquisition system, the moving clutter Doppler spectrum is measured and analyzed in terms of a various operational parameters.