Multistage algorithms for extended dwell target detection

Abstract

Improvements in detecting weak targets from a small radar platform must come through increased temporal integration, i.e., extending the time over which target samples are coherently integrated. Conventional single-channel radar assumes a linear-phase signal model that is only accurate over a short dwell time for typical target motion. Over an extended dwell, the target signal includes multiple nonlinear phase components, each of whose effects become significant at different times during the dwell. An algorithm is presented that develops a multiphase signal model in multiple stages based on these times. A modification of the proposed approach improves the signal model for the most challenging targets. When used as the detection filter, the multiphase signal model yields near optimal performance over an extended dwell time for a wide range of target parameters. Typical improvement in output signal-to-noise ratio (SNR) for a 500 ms dwell is 12−13 dB over conventional processing.

Multichannel GMTI techniques to enhance integration of temporal signal energy for improved target detection

“…Prior research devoted to target detection over a long coherent processing interval (CPI) primarily considers single‐channel methods [9–17] that either process the extended‐dwell signal with transforms that are best suited to strong targets or assume target motion is limited to a single component of radial velocity. A more recent single‐channel approach detailed in [18] is well‐suited for weak targets with non‐linear range rate; however, processing methods used to determine the linear and non‐linear phase components of the extended dwell temporal signal require computations that make real‐time implementation impractical. In addition to the challenges of accurately modelling a low‐SNR, extended‐dwell‐time signal in [9–17] or the computational burden of the extended dwell algorithm in [18], these single‐channel methods provide suboptimal clutter mitigation and limited target spatial information in comparison with multichannel methods.…”

“…A more recent single‐channel approach detailed in [18] is well‐suited for weak targets with non‐linear range rate; however, processing methods used to determine the linear and non‐linear phase components of the extended dwell temporal signal require computations that make real‐time implementation impractical. In addition to the challenges of accurately modelling a low‐SNR, extended‐dwell‐time signal in [9–17] or the computational burden of the extended dwell algorithm in [18], these single‐channel methods provide suboptimal clutter mitigation and limited target spatial information in comparison with multichannel methods. Several recent methods combine multichannel processing concepts with synthetic aperture radar imaging techniques to improve the image quality of a stationary ground scene [19, 20].…”

“…Several recent methods combine multichannel processing concepts with synthetic aperture radar imaging techniques to improve the image quality of a stationary ground scene [19, 20]. In contrast to methods in [9–20], this paper presents a multichannel solution based on two modifications to element‐space pre‐Doppler STAP [3, 4] which are used in conjunction to improve detection of slow‐moving targets first by maximising the SINR of the pre‐Doppler temporal signal and then by combining temporal signal energy collected over an extended dwell time in a unique way that exploits the differences between target signal energy and noise energy.…”