Showing papers on "Moving target indication published in 2001"
TL;DR: It is shown that, for similar tracking performance, the optimal Bayes tracker can achieve peak signal-to-noise ratio gains possibly larger than 10 dB over the commonly used combination of a spatial matched filter (spatial correlator) and a linearized Kalman-Bucy tracker.
Abstract: We develop the optimal Bayes multiframe detector/tracker for rigid extended targets that move randomly in clutter. The performance of this optimal algorithm provides a bound on the performance of any other suboptimal detector/tracker. We determine by Monte Carlo simulations the optimal performance under a variety of scenarios including spatially correlated Gaussian clutter and non-Gaussian (K and Weibull) clutter. We show that, for similar tracking performance, the optimal Bayes tracker can achieve peak signal-to-noise ratio gains possibly larger than 10 dB over the commonly used combination of a spatial matched filter (spatial correlator) and a linearized Kalman-Bucy tracker. Simulations using real clutter data with a simulated target suggest similar performance gains when the clutter model parameters are unknown and estimated from the measurements.
75 citations
01 Jun 2001
TL;DR: In this article, a new sensor model adapted to space-time adaptive processing (STAP) is proposed and its benefits to tracking well-separated targets are discussed and the model in particular provides a more appropriate treatment of missing detections.
Abstract: The problem of tracking ground moving targets by a moving radar (airborne, spaceborne) is addressed. Tracking of low Doppler targets within a strong clutter background is of special interest. The motion of the radar platform induces a spreading of the clutter Doppler spectrum so that low Doppler target echoes may be buried in the clutter band. Detection of such targets can be much alleviated by space–time adaptive processing (STAP), which implicitly compensates for the Doppler spread effect caused by the platform motion. Even if STAP is applied, low Doppler targets can be masked by the clutter notch. This physical phenomenon is frequently observed and results in a series of missing detections which may seriously degrade the tracking performance. A new sensor model adapted to STAP is proposed and its benefits to tracking well-separated targets are discussed. By exploiting a priori information on the sensor specific clutter notch, the model in particular provides a more appropriate treatment of missing detections. In this context, the minimum detectable velocity (MDV) proves to be an important sensor parameter, explicitly entering into ground moving target indication (GMTI) tracking.
63 citations
TL;DR: The generic characteristics and performance of an experimental long-range air-surveillance radar, known at the Naval Research Laboratory as Senrad, is described, which can operate with simultaneous transmissions over a very wide bandwidth-from 850 to 1400 MHz.
Abstract: The generic characteristics and performance of an experimental long-range air-surveillance radar, known at the Naval Research Laboratory as Senrad, is described. Its distinguishing feature is that it can operate with simultaneous transmissions over a very wide bandwidth-from 850 to 1400 MHz. The technology and type of experimental radar equipment employed are discussed and examples are given of its performance capabilities obtained by means of very wideband operation. The unusually wide bandwidth of this radar allows 1) improved detection and tracking performance because of the absence of the nulls that are common in the antenna elevation radiation-pattern of a single-frequency radar; 2) moving target indication (MTI) without loss of targets due to blind speeds and without the need for multiple PRFs (pulse repetition frequencies); 3) accurate height finding with a fan-beam radar by taking advantage of the multipath time difference as a function of target height; 4) a form of limited target recognition based on high range-resolution; and 5) a reduction of the effectiveness of electronic countermeasures that can seriously degrade more narrowband radars.
46 citations
01 Jul 2001
TL;DR: In this article, the authors examined the statistics of the phase and magnitude of SAR interferograms towards the deployment of along-track interferometry (ATI) for slow ground moving target indication (GMTI).
Abstract: : This report examines the statistics of the phase and magnitude of SAR interferograms towards the deployment of along-track interferometry (ATI) for slow ground moving target indication (GMTI). Great importance is attached to the practical applicability of the derived theoretical results, particularly with regard to the experimental MTI-mode of Radarsat2. Therefore, the results are evaluated with experimental airborne SAR data acquired during flight trials conducted in Petawawa in 1999. While the known probability density function (pdf) of the interferogram's phase (derived under the assumption of Gaussian backscatter) is shown to agree almost perfectly for a wide variety of backscatter conditions, the corresponding magnitude's pdf tends to deviate strongly in most cases. Motivated by this discrepancy, a novel distribution is derived for the interferogram's magnitude. This pdf, called the polynomial or p-distribution, matches the real data much more accurately, particularly for extremely heterogeneous composite terrain. Based on these statistics, a completely automatic detection scheme with constant false alarm rates for slow moving targets is proposed. All involved parameters required to determine the detection thresholds are estimated from the sample data. It is demonstrated on the basis of a real SAR scene that this detector is capable of detecting slow moving vehicles within severe ground clutter. Finally, practical aspects of the implementation and numerical stability are addressed, since many of the functions involved are comprised of indefinite power series which have to be handled cautiously.
43 citations
TL;DR: The feature extraction of moving targets in the presence of temporally and spatially correlated ground clutter for airborne high-range resolution (HRR) phased-array radar is studied and a relaxation-based high-resolution feature extraction algorithm is proposed, RELAX.
Abstract: We study the feature extraction of moving targets in the presence of temporally and spatially correlated ground clutter for airborne high-range resolution (HRR) phased-array radar. To avoid the range migration problems that occur in HRR radar data, we first divide the HRR range profiles into low-range resolution (LRR) segments. Since each LRR segment contains a sequence of HRR range bins, no information is lost due to the division, and hence, no loss of resolution occurs. We show how to use a vector auto-regressive (VAR) filtering technique to suppress the ground clutter, Then, a parameter estimation algorithm is proposed for target feature extraction. From the VAR-filtered data, the target Doppler frequency and the spatial signature vectors are first estimated by using a maximum likelihood (ML) method. The target phase history and direction-of-arrival (DOA) (or the array steering vector for an unknown array manifold) are then estimated from the spatial signature vectors by minimizing a weighted least squares (WLS) cost function. The target radar cross section (RCS)-related complex amplitude and range-related frequency of each target scatterer are then extracted from the estimated target phase history by using RELAX, which is a relaxation-based high-resolution feature extraction algorithm. Numerical results are provided to demonstrate the performance of the proposed algorithm.
43 citations
01 May 2001
TL;DR: This work proposes a model for seeding the radar data cube with target signals and calculates both asymptotic and finite training data detection losses for STAP in ground moving target indication (GMTI) scenarios.
Abstract: We consider the impact of target signals corrupting the covariance estimate when implementing STAP in ground moving target indication (GMTI) scenarios. Herein, we propose a model for seeding the radar data cube with target signals and calculate both asymptotic and finite training data detection losses. In general, both the location and strength of the corruptive target signals influence performance: under practical conditions, SINR loss can exceed 10 dB. Measured MCARM data confirms the presence of ample ground moving target signals in the radar field of regard under typical operating conditions. We conclude by briefly considering several mitigating strategies as well.
41 citations
TL;DR: A relaxation-based algorithm, which is robust and computationally simple, is proposed to deal with the problem of extracting the HRR features of moving targets with very closely spaced scatterers in the presence of strong stationary clutter.
Abstract: High range resolution (HRR) moving target indicator (MTI) is becoming increasingly important for many military and civilian applications such as the detection and classification of moving targets in strong clutter background. We consider the problem of extracting the HRR features of moving targets with very closely spaced scatterers in the presence of strong stationary clutter, where the range migration and Doppler frequency are taken into account. A relaxation-based algorithm, which is robust and computationally simple, is proposed to deal with the above problem. Numerical results have shown that the proposed algorithm exhibits super resolution and excellent estimation performance.
38 citations
TL;DR: It is shown that accurate georegistration can be obtained even with a small number of measurements in target tracking systems and that these biases can be estimated in such a scenario, i.e., they meet the complete observability condition.
Abstract: In target tracking systems: using GMTI (ground moving target indicator) radars on airborne platforms, the locations of these platforms are available from GPS-based estimates. However, these estimated locations are subject to errors that are, typically, stationary autocorrelated random processes, i.e., slowly varying biases. In situations where there are no known-location targets to estimate these biases, the next best recourse is to use targets of opportunity at fixed but unknown locations. Such targets can be, e.g., static rotators (ground-based radars with rotating antenna), which yield detections in moving target indicator (MTI) radars. It is shown that these biases can be estimated in such a scenario, i.e., they meet the complete observability condition. Following this, the achievable accuracy for a generic scenario is evaluated. It is shown that accurate georegistration can be obtained even with a small number of measurements.
29 citations
TL;DR: A moving target detector based on a generalized likelihood ratio test (GLRT) detection strategy is derived and a simple detection variable is computed and compared with the detection threshold to render a decision on the presence of a target.
Abstract: We study moving target detection in the presence of temporally and spatially correlated ground clutter for airborne high range resolution (HRR) phased array radar. We divide the HRR range profiles into large range segments to avoid the range migration problems that occur in the HRR radar data. Since each range segment contains a sequence of HRR range bins, no information is lost due to the division and hence no loss of resolution occurs. We show how to use a vector autoregressive (VAR) filtering technique to suppress the ground clutter. Then a moving target detector based on a generalized likelihood ratio test (GLRT) detection strategy is derived. The detection threshold is determined according to the desired false alarm rate, which is made possible via an asymptotic statistical analysis. After the target Doppler frequency and spatial signature vectors are estimated from the VAR-filtered data as if a target were present, a simple detection variable is computed and compared with the detection threshold to render a decision on the presence of a target. Numerical results are provided to demonstrate the performance of the proposed moving target detection algorithm.
22 citations
26 Nov 2001
TL;DR: In this paper, the minimum detectable velocity (MDV) is used to improve the accuracy of ground surveillance with airborne GMTI radar, which can be combined with road map information or sensor data fusion.
Abstract: The aim of ground surveillance with airborne GMTI radar is the near real-time production of a dynamic ground picture. Since the sensors often record merely certain aspects of the situation of interest, information fusion is of particular importance. In addition, even after platform motion compensation by signal processing techniques (STAP), ground moving targets can well be masked by the clutter notch of the sensor. This physical phenomenon directly results from the low-DOPPLER characteristics of the targets and causes interfering fading effects that seriously affect the tracking performance/continuity. In this context a GMTI sensor model provides significant performance improvements being relevant also to sensor data fusion. The Minimum Detectable Velocity (MDV) proves to be an important sensor parameter explicitly entering into GMTI tracking. In combination with road map information or sensor data fusion the refined model can in particular alleviate the recognition of stopping targets. A numerical example quantitatively illustrates the potential gain by exploiting GMTI-modeling, road-maps, and sensor fusion.
22 citations
01 Feb 2001
TL;DR: In this paper, the use of a bistatic antenna configuration for ground moving target indication in an ultra-wideband and widebeam synthetic aperture radar system is discussed, and an attempt is made to estimate the Bistatic effects on clutter scattering cannot be compensated.
Abstract: The use of a bistatic antenna configuration for ground moving target indication in an ultra-wideband and widebeam synthetic aperture radar system is discussed. To suppress the strong clutter signal the radar channels have a strict requirement on equality. In a bistatic system they are not equal, and the author investigates how to compensate for the bistatic configuration. Bistatic effects on clutter scattering cannot be compensated, and an attempt is therefore made to estimate the bistatic scattering influence of the ground moving target indication. The bistatic to monostatic synthetic aperture inversion in a wide antenna beam is derived in both the time and the frequency domain. The mismatch between the radar channels will cause clutter leakage. The pulse compressed impulse response leakage is determined both for the time and frequency domains.
03 May 2001
TL;DR: In this article, a new method of target coherent range ambiguity resolution is presented, which is substantially different from previously proposed methods and eliminates the generation of target ghosts associated with most conventional techniques.
Abstract: A new method of target coherent range ambiguity resolution is presented which is substantially different from previously proposed methods. The new target ranging eliminates the generation of target ghosts associated with most conventional techniques. A range-ambiguous radar with a medium to high pulse repetition frequency is assumed. Clutter is assumed to be present in multiple range intervals. The method utilizes constant frequency pulses that change phase pseudo-randomly from pulse to pulse. The phase progression of the received pulses are correlated with a bank of matched filters constructed using phase progressions representative of the different range intervals. Performance degradation of target detection using the pseudo-random phases is also examined. Target detection with strictly pseudo-random phases is found to degrade in comparison to the conventional constant phase methods. A technique that utilizes both constant phase and pseudo-random phases is proposed that performs both detection and target ranging well.
10 Mar 2001
TL;DR: It is shown that clutter within the main lobe of the individual aperture pattern can indeed be separated from the targets, using the deterministic geometric relationship between observation direction and clutter Doppler shift.
Abstract: A method of performing space based Ground Moving Target Indication (GMTI) using radar interferometric processing is presented The algorithm, referred to as Scanned Pattern Interferometric Radar (SPIR), uses the high angular variability of a sparse array Point Spread Function (PSF) to collect sufficient data from the signal return that the clutter and targets can be separated without an a priori assumption of the clutter statistics It is shown that clutter within the main lobe of the individual aperture pattern can indeed be separated from the targets, using the deterministic geometric relationship between observation direction and clutter Doppler shift If the computational domain is extended to the side lobes of the gain pattern, clutter entering through these lobes can also be extracted Constraints on the cluster geometry are derived from the invertibility of the PSF matrix
TL;DR: In this article, the authors describe the design and implementation of multiple model nonlinear filters (MMNLF) for ground target tracking using Ground Moving Target Indicator (GMTI) radar measurements.
Abstract: This paper describes the design and implementation of multiple model nonlinear filters (MMNLF) for ground target tracking using Ground Moving Target Indicator (GMTI) radar measurements. The MMNLF is based on a general theory of hybrid continuous-discrete dynamics. The motion model state is discrete and its stochastic dynamics are a continuous- time Markov chain. For each motion model, the continuum dynamics are a continuous-state Markov process described here by appropriate Fokker-Plank equations. This is illustrated here by a specific two-model MMNLF in which one motion model incorporates terrain, road, and vehicle motion constraints derived from battlefield observations. The second model is slow diffusion in speed and heading. The target state conditional probability density is discretized on a moving grid and recursively updated with sensor measurements via Bayes' formula. The conditional density is time updated between sensor measurements using Alternating Direction Implicit (ADI) finite difference methods. In simulation testing against low signal to clutter + noise Ratio (SNCR) targets, the MMNLF is able to maintain track in situations where single model filters based on either of the component models fail. Potential applications of this work include detection and tracking of foliage-obscured moving targets.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
03 May 2001
TL;DR: The AN/APY-6 is an X-band radar developed by Northrop Grumman under ONR (Office of Naval Research) sponsorship and was installed in a USA Navy NP-3 aircraft in July 1999.
Abstract: The AN/APY-6 is an X-band radar developed by Northrop Grumman under ONR (Office of Naval Research) sponsorship. It was developed to provide all-speed target detection, location, tracking, imaging and exploitation. It was installed in a USA Navy NP-3 aircraft in July 1999 and continues to undergo testing and demonstration in the NP-3. This paper presents test results in the form of SAR, GMTI and tracking imagery obtained from programs in which the NP-3 has participated. These include the DARPA Affordable Moving & Stationary Target Exploitation (AMSTE) GMTI precision location program and a number of USN fleet battle exercises (FBE) and the NATO Clean Hunter 2000 exercises.
01 Jan 2001
TL;DR: This paper addresses the issue of adaptive weight training in space-time adaptive processing (STAP) algorithms for airborne radar in non-homogeneous clutter environments, while avoiding the inclusion of target signals in the training.
Abstract: This paper addresses the issue of adaptive weight training in space-time adaptive processing (STAP) algorithms for airborne radar in non-homogeneous clutter environments, while avoiding the inclusion of target signals in the training. A common method of ensuring STAP clutter cancellation performance in the presence of strong clutter discretes is to train the STAP adaptive weights using the returns with the largest power for a given Doppler bin. The presumption is that the strongest returns are from the strongest clutter. Many times, however, targets are also present whose inclusion in the STAP weight training results in significant target self-nulling as well as a degradation in clutter mitigation performance. A new STAP training method is presented that excises targets from the training set based on an interferometric measurement of phase for each potential STAP training sample. The resulting training method based on both phase and power selection criteria is shown to offer significant performance gains on experimental data.
15 Oct 2001
TL;DR: A new robust 2D-OS-CFAR detector is developed to resolve existent problems, with CFAR processing on a two-dimensional R-Fd (range-Doppler frequency) plane in place of the conventional one-dimensional range.
Abstract: The problems of CFAR processing are investigated by means of real cloud clutter data. Based on FFT processing techniques, a comparison of cloud clutter suppressing performance is made between CAGO-CFAR detectors, 3D-CLUTTER MAP-CFAR detectors and MX-OS-CFAR detectors. A new robust 2D-OS-CFAR detector is developed to resolve existent problems, with CFAR processing on a two-dimensional R-Fd (range-Doppler frequency) plane in place of the conventional one-dimensional range. Order statistics are used to estimate clutter amplitude at the same time. The processing results of real cloud clutter and target simulation signals have verified excellent performances of the 2D-OS-CFAR detector.
TL;DR: A new ultra-wideband technique, based on the E-pulse concept, is shown to be effective in maximizing the target to clutter ratio and to demonstrate the usefulness of this method.
Abstract: A new ultra-wideband technique to detect a sea-skimming missile in a sea-surface clutter background is presented. This technique, based on the E-pulse concept, is shown to be effective in maximizing the target to clutter ratio. Results using both measured and theoretical data from simulated sea surfaces demonstrate the usefulness of this method.
01 Aug 2001
TL;DR: In this paper, the results of publicly available data and analyses are applied to a specific strawman FOPEN space-based radar (SBR) system operating from low-Earth orbit.
Abstract: : This report provides the results of a brief study of the possible effects of ionospheric scintillation on a space-based, foliage-penetration (FOPEN), ground moving-target indication (GMTI) radar operating in the ultrahigh-frequency (UHF) band. The results of publicly available data and analyses are applied to a specific strawman FOPEN space-based radar (SBR) system operating from low-Earth orbit. Performance degradations due to ionospheric scintillation and a combination of ionospheric scintillation and internal clutter motion caused by wind are calculated for a 3 m/s target minimum detectable velocity (MDV) at 15-deg grazing, point parameters felt to be minimally acceptable for an operational system. Space-time adaptive processing (STAP) is used to provide the clutter rejection necessary for successful performance. Implications of ionospheric scintillation for synthetic aperture-based GMTI processing are also discussed.
15 Oct 2001
TL;DR: In this article, the authors proposed an effective image sequence processing scheme based on analyzing the targets and background model correctly. But, this method focuses on reducing the cost of computation, tracking the target in real-time, enhancing the SNR, and suppressing the clutter.
Abstract: This paper presents an algorithm of designing an effective image sequence processing scheme, which based on analyzing the targets and background model correctly. This algorithm will successfully detect very small (point) target in spatially varying clutter background when both the target and clutter are moving through the image scene. This method focuses on reducing the cost of computation, tracking the target in real-time, enhancing the SNR, and suppressing the clutter.
15 Oct 2001
TL;DR: In this article, the imaging method of a low-altitude target in strong ground clutter is presented, where the identical amount of stretching time-delay with the adjoined echoes is applied in the signal stretching process, and then the ground clutter are filtered through the one-order canceller.
Abstract: The imaging method of a low-altitude target in strong ground clutter is presented. The identical amount of stretching time-delay with the adjoined echoes is applied in the signal stretching process, and then the ground clutter is filtered through the one-order canceller. Furthermore the target's motion parameters can be accurately estimated by the narrow pulse signals on the constant carrier, so that motion compensation can be achieved. After the theoretical analysis, the validity is proven by simulation results.
01 May 2001
TL;DR: A GMTI (ground moving target indicator)/geolocation algorithm is derived to assist with track maintenance during periods of GMTI data blackout, and a geolocation estimator is presented which fuses time difference of arrival (TDOA), frequency difference of arrivals (FDOA, and angle of arrival) measurements.
Abstract: In modern tactical environments, information from a variety of sensors may be simultaneously utilized to improve target detection and tracking procedures. Towards this goal, two data fusion algorithms are developed that implement such processing. First, a GMTI (ground moving target indicator)/geolocation algorithm is derived to assist with track maintenance during periods of GMTI data blackout. Next, a geolocation estimator is presented which fuses time difference of arrival (TDOA), frequency difference of arrival (FDOA), and angle of arrival (AOA) measurements. These algorithms lead to improved positional estimation, track accuracy, and track maintenance. They also potentially reduce the number of platforms required to successfully locate and track targets.
05 Nov 2001
TL;DR: This scheme provides more efficient clutter suppression for non-stationary clutter and provides the ability to detect a slow moving target and the computer simulation is presented to compare the performance of this adaptive clutter suppression technique.
Abstract: The clutter return presents a severe problem in target detection for radar systems. Conventional radar systems assume the clutter is stationary, with energy concentrated in the low frequency domain. To minimize the effect of clutter, radar systems use a fixed high pass filter (HPF) to eliminate the clutter. When the target Doppler frequency is below the cutoff frequency of the high pass filter, or the clutter energy does not concentrate on the low frequency domain, the performance of radar system is severely degraded. This paper proposes an adaptive clutter suppression scheme. This scheme provides more efficient clutter suppression for non-stationary clutter and provides the ability to detect a slow moving target. The computer simulation is presented to compare the performance of this adaptive clutter suppression technique and the fixed clutter suppression filter.
01 May 2001
TL;DR: An extensible method for modelling large complex radar systems that can be used to model platform and target motion, analogue and digital electronic components and complex signal processing algorithms is described.
Abstract: This paper describes an approach to modelling synthetic aperture radar (SAR) and ground moving target identification (GMTI) modes that is applicable to both monostatic and bistatic operation. We describe an extensible method for modelling large complex radar systems that can be used to model platform and target motion, analogue and digital electronic components and complex signal processing algorithms. The key to this approach is a common data file format that allows the user to exchange simulated datasets for real flight trials data or combine the two without any recompilation of the modelling.
01 Oct 2001
TL;DR: In this article, the authors examined the small sample size performance of different fast fully adaptive space-time processors (STAP) and compared it to the optimum-detector performance.
Abstract: : In ground surveillance from an airborne or space-based radar it is desirable to be able to detect small moving targets, such as tanks or wheeled vehicles, within severe ground clutter For operational moving target indication (MTI) systems the clutter filter coefficients have to be updated frequently due to rapidly changing interference environment This report examines the small sample size performance of different fast fully adaptive space-time processors (STAP) and compares it to the optimum-detector performance These recently proposed techniques, named Matrix Transformation based Projection (MTP) and Lean Matrix Inversion (LMI), were originally developed to provide fast man-made jammer suppression in large surface phased array radars with many elements For this application they have been proven to operate with near-optimum performance, yet with a computational expense drastically reduced from that of the optimum detector in most practical cases The investigation herein focuses on the performance achieved when only a few data samples are available to adapt (update) the clutter filter coefficient In this report, the techniques are described and a number of simulations carried out The two applications, STAP and jammer suppression, are similar; both are required to suppress an interference which is characterized by a certain number of dominant eigenvalues of the sample space-time covariance matrix Despite the similarities the performance between the two differs due to the different shapes of their eigenvalue distribution The LMI is shown to give the best Signal-to-Noise-plus-Clutter Ratio (SNCR) for a given computational load
01 May 2001
TL;DR: Moving target indication (MTI) is demonstrated for general antenna arrays, especially sparse 3D arrays, and the optimum detector and the minimum norm eigen canceler (MNE) are implemented through simulation to demonstrate effective clutter cancellation.
Abstract: Moving target indication (MTI) is demonstrated for general antenna arrays, especially sparse 3D arrays. The framework for space-time adaptive processing (STAP) is generalized to include frequency (fast-time) data and array elements offset in cross track dimensions. The degrees of freedom (rank) needed to represent clutter are derived for general systems. The clutter rank compared to the number of independent samples collected by a radar determine whether MTI is achievable. The optimum detector and the minimum norm eigen canceler (MNE) are implemented through simulation to demonstrate effective clutter cancellation.
Journal Article•
TL;DR: An infrared point target detection algorithm based on two filters in spatially varying clutter that can reduce the cost of computation, track the target in real-time, enhance the SNR, and suppress the clutter effectively.
Abstract: In this paper, an infrared point target detection algorithm based on two filters in spatially varying clutter is presented. The target and clutter model is analyzed correctly, and very small (point) target under spatially varying clutter background is successfully detected with the algorithm, when the target and clutter are both moving across the image scene. This method can reduce the cost of computation, track the target in real-time, enhance the SNR, and suppress the clutter effectively. \;
01 May 2001
TL;DR: This work proposes to use synthetic aperture radar (SAR) imagery to enhance the detection performance of GMTI radar by using a multiresolution Markov model to represent both target and background clutter.
Abstract: A difficult problem with ground moving target radar (GMTI) detection is how to consistently track targets moving through non-homogeneous regions of clutter such as forest and urban boundaries. Although attempts have been made to mitigate this detection problem using terrain mapping data, such data does not give current clutter information due to change in vegetation, roads, buildings, and seasonal variation. We propose to use synthetic aperture radar (SAR) imagery to enhance the detection performance of GMTI radar. We use a multiresolution Markov model to represent both target and background clutter. This multiresolution structure allows us to accurately match GMTI clutter with the geographically registered SAR imagery for consistent moving target detection through clutter boundary areas.
15 Oct 2001
TL;DR: It is shown that the two methods for estimating the center frequency and bandwidth, separately called centroid method (CM) and energy integration method (EIM), are effective for short-time clutter data in practical application.
Abstract: Two methods for estimating the center frequency and bandwidth, separately called centroid method (CM) and energy integration method (EIM), are proposed. A comparison of the complexity and the performance between the two methods and the general ones is presented. It is shown that the two methods are effective for short-time clutter data in practical application.
15 Oct 2001
TL;DR: In this article, the stability of MTI radar measured as the ratio of power of test signal residue in the target filter to power of the test signal in the clutter filter does not necessarily correspond to the actual system stability over the range of test SNO ratios.
Abstract: The stability of MTI radar measured as the ratio of power of test signal residue in the target filter to power of the test signal in the clutter filter does not necessarily correspond to the actual system stability over the range of test signal-to-noise ratios. The stability measurement algorithm should be based on the signal-to-noise ratio for which both figures match each other (that in the general case depends on the number of pulses and set of coefficients used to create a canceler or Doppler filter bank) or a correction coefficient should be introduced to account for possible discrepancy between measured and actual stability figures.