Optimum relative speed discretisation for detection of moving objects in wide band SAR

Abstract

This is an author produced version of a paper published in IET Radar, Sonar and Navigation. This paper has been peer-reviewed but may not include the final publisher proof-corrections or journal pagination.Citation for the published paper: Mats I. Pettersson Optimum relative speed discretisation for detection of moving objects in wide band SAR IET Radar, Sonar and Navigation Volume 1, Issue 3, page 213-220, Year 2007 Access to the published version may require subscription. Published with permission from: IET Abstract: This paper considers Ground Moving Target Indication (GMTI) using Synthetic Aperture Radar (SAR). SAR GMTI requires that Relative Speed between the target and the SAR platform is included in the detection algorithm. A separation between the true Relative Speed and the Relative Speed used in the SAR process will cause unfocused targets, and decrease detectability. Blind hypotheses of Relative Speeds are used in the detection phase of moving targets in SAR.The step size between the hypotheses (or, discretization step) in Relative Speed involves a trade off between the number of hypotheses to test and detectability. A large number of tests will increase detectability but will also increase computation load and vice versa. The relevance of Relative Speed increases as the azimuth integration time gets larger. Long integration time is associated with low signature moving target detection in strong clutter environments, or for SAR GMTI at low frequencies. In this paper we determine the optimum discretization of Normalized Relative Speed (NRS) for moving target detection. The optimum discretization is derived from the moving target impulse response. Use of optimum discretization reduces the computation burden in SAR GMTI and secures the detectability.

Moving Target Relative Speed Estimation and Refocusing in Synthetic Aperture Radar Images

“…Using the GBP integral [15] combined with NRS [19], the image response can be represented by (10), where X p and Y p are the processed SAR images pixels and s pc is the pulse-compressed target radar echo [26]. To evaluate the…”

Four-dimensional discretization for detection of moving objects in Wide Band SAR

“…For detection, different hypotheses on range migration and bearing are tested in (6). The hypothesis of range migration is given by…”

“…Considering a WB SAR the width changes over the integration interval of k in (6). Because the smallest width is associated with the largest k, we select max k k = in equation (6) in order to ensure secure detection, and we rewrite (6) as ( ) However, [6] demonstrates that it is also a good approximation for large apertures.…”

Ground Moving Target Trajectory Reconstruction in Single-Channel Circular SAR

“…The first category concerns moving target detection and tracking with multiple aperture antennas SAR. This category relies on Displaced Phase Center Array (DPCA) [3], Space-Time adaptive processing (STAP) [4], along-track interferometry (ATI) [5] and detection by focusing using different full velocity vector hypothesis [6]. One advantage of these techniques is the ability to suppress clutter.…”