Diverse, orthogonal waveforms and signal processing architecture for joint GMTI and SAR applications

Abstract

In this research, we introduce a signal processing framework for joint GMTI and SAR algorithms that is based on orthogonal (transmit and receive) waveforms. Traditionally, radar systems are configured to operate either in GMTI or SAR processing mode, but not both simultaneously. This is due to the fact that operational parameters for these two modes are quite different. For example, exoclutter GMTI processing requires a high pulse repetition frequency (PRF), but a high PRF results in increased range ambiguity - and an increased processing burden - in SAR imaging. We propose combining diverse, orthogonal waveforms and introducing corresponding processing techniques to reduce the problems and complexities of joint GMTI and SAR exploitation. For the exoclutter GMTI problem, the necessary high-PRF pulse train will be used to achieve finer Doppler resolution for detecting fast moving objects. For the endoclutter GMTI and SAR imaging problem, we will transmit low PRF pulses. The goal for low PRF pulses for endoclutter GMTI and SAR imaging is to ensure that range ambiguity issue has been addressed. These new approaches will achieve following benefits: (1) accomplish GMTI and SAR processing concurrently by eliminating the complexities associated with reconfiguring a radar system, (2) more efficiently use bandwidth by employing appropriate bandwidth for exoclutter GMTI pulses and SAR image formation pulses, and (3) reduce range ambiguity issue associated with high PRF operation.