Moving target indication

About: Moving target indication is a research topic. Over the lifetime, 2653 publications have been published within this topic receiving 32435 citations.

A Novel Deceptive Jamming Method Against Two-Channel SAR-GMTI Based on Two Jammers

Abstract: The traditional synthetic aperture radar (SAR) deceptive jamming can effectively create false static and moving targets in the SAR image. However, the deceptive capability could be significantly reduced or denied by the two-channel SAR-ground moving target indication (GMTI) system. To achieve the effective deception, the impact of SAR deceptive jamming against two-channel SAR-GMTI system is first analyzed. Then, a novel effective deceptive jamming method based on two jammers is described. Using this method, the two stationary jammers are made to be located at different positions along the azimuth direction. By applying the complex modulation in each jammer, the additional phase term of the synthetic jamming signals in the two coregistered SAR images is canceled. It is shown that the expected modulation coefficient for each jammer can be precisely calculated by solving a linear system of equations of two unknowns. Finally, the proposed deceptive jamming against the two-channel SAR-GMTI system is achieved by generating the jamming signal in each jammer via the efficient deceptive jamming technique. By utilizing the optimal layout of the jammers, this scheme is both robust and computationally efficient. It will generate false static and moving targets with high fidelity in the two SAR images. Only the false moving targets can be detected by the displaced phase center antenna (DPCA) and then relocated to the correct positions by along-track interferometry (ATI) in the two-channel SAR-GMTI system. Some simulations are provided to demonstrate the effectiveness of the proposed method.

Joint Monostatic and Bistatic STAP for Improved SAR-GMTI Capabilities

Abstract: This paper proposes a novel simultaneous monostatic and bistatic ground moving target indication (GMTI) mode for improved target detection and imaging capability. The mode uses an airborne multichannel radar system and a stationary transmitter. Both systems transmit simultaneously on adjacent frequency bands, and the airborne multichannel system receives both its monostatic echoes and the bistatic returns. Geometrical diversity between the monostatic and bistatic measurements enhances moving target detection capabilities. Moreover, for movers detected in both data sets, an estimation of the target velocity vector (i.e., velocity and direction of motion) can be performed. By simply extracting a single-channel data set, this also allows correct focusing of moving targets both in monostatic and bistatic data sets, if synthetic aperture radar GMTI capability is required. Consequently, situational awareness over the observed area is greatly improved. The effectiveness of the proposed technique is analyzed both from a theoretical point of view and by means of an ad hoc experiment conducted by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) in fall 2013.

Impact of experimentally measured Doppler spectrum of ground clutter on MTI and STAP

Abstract: The experimental measurement of the Doppler spectrum of the ground clutter has revealed an exponential shape in contrast to the commonly used Gaussian shape. The goal of this paper is to investigate its consequences on two practical applications, namely: clutter cancellation and target detection with coherent optimum MTI on ground based radar and with space-time adaptive processor (STAP) on airborne radar. The experimental evidence of the Doppler spectrum for ground clutter is included and the improvement factor of an optimum MTI is compared for Gaussian shaped as well as exponentially shaped clutter spectrum. The loss of improvement factor (IF) and the reduction of the target visibility as a function of the target Doppler frequency and of the number of integrated pulses are evaluated. A similar analysis is also presented for the case of an airborne radar equipped with a digital beam forming and a STAP.

A digital beamforming processor for the joint DoD/NASA space based radar mission

Abstract: The space based radar (SBR) program includes a joint technology demonstration between NASA and the Air Force to design a low-earth orbiting, 2/spl times/50 m L-band (1.26 GHz) radar system for both Earth science and intelligence-related observations. A key subsystem aboard SBR is the electronically-steerable digital beamformer (DBF) network that interfaces between 32 smaller sub-antenna panels in the array and the on-board processing electronics for synthetic aperture radar (SAR) and moving target indication (MTI). In this paper, we describe the development of a field-programmable gate array (FPGA) based DBF processor for handling the algorithmically simple yet computationally intensive inner-product operations for wideband, coherent beamforming across the 50 m length of the array. Tests with an antenna array simulator demonstrate that the beamformer performance metrics (0.07/spl deg/ rms phase precision per channel, -39.0 dB peak sidelobe level) will meet the system-level requirements for SAR and MTI operating modes.

Differential Geometry Measures of Nonlinearity for Ground Moving Target Indicator (GMTI) Filtering

Abstract: The ground moving target indicator (GMTI) radar is widely used to detect, geolocate, track, and classify ground-moving targets in all weather, day-night, and cluttered conditions. The measurements of a GMTI radar are slant range, azimuth, and range-rate or Doppler. These measurements are nonlinear functions of the target state. Until recently, a quantitative measure of the degree of nonlinearity (DoN) for nonlinear filtering problems was lacking. Recently, the DoN of a filtering problem with a nonlinear measurement model has been quantified using the differential geometry based measures of nonlinearity such as the parameter-effects curvature and intrinsic curvature. We calculate three types of parameter-effects curvature and intrinsic curvature for the nonlinear GMTI filtering problem for a variety of scenarios. We vary the distance between the target and the GMTI sensor in these scenarios using simulated data. We demonstrate that the state estimation mean square error (MSE) increases with increase in the DoN