Ground moving target indication using multi-channel SAR with non-uniform displaced phase centers

Abstract

This paper presents an evaluation of a post-Doppler spacetime\ud adaptive Processing (STAP) technique for non-uniformly\ud displaced phase center receivers synthetic aperture radar\ud (SAR). Both theoretical and simulation analysis are carried\ud out in order to prove the ground moving target indication\ud (GMTI) capabilities for specific non-uniformly spaced multichannel\ud configurations on-board a single satellite platform.\ud Simulated SAR data in the maritime scenario show improved\ud performance, specially for small and slow targets, compared\ud to current SAR missions, equipped with just two channels.Peer ReviewedPostprint (published version

A Performance Evaluation of SAR-GMTI Missions for Maritime Applications

“…During this time frame sea has evolved, and so clutter returns have decorrelated from a statistical standpoint. For the longest baseline separation and 10 ms coherence time, sea clutter coherence drops off to values around 0.15 according to (7). This is directly translated into a GMTI performance degradation, as pointed out by the theoretical and simulation results.…”

“…1(a)), where the two external antennas are deployed using a telescopic boom, as suggested in [7], [17], and as an unfolding system, respectively. The number of channels has been selected to limit system complexity and at the same time to fulfill the required degrees of freedom driven by the eigenvalue distribution of the interference covariance matrix, as discussed in section IV-B.…”

“…It can be theoretically demonstrated that for v z = 0 m/s and in the limit of zero clutter coherence between the different channels, IF tends to the number of channels M , since in this case clutter has no spatial structure and behaves like noise. As the worst clutter coherence is 0.15 according to (7) for the longest baseline and a 10 ms clutter coherence time, IF is expected to be lower than M.…”

“…To complement the MC simulations, synthetic multichannel data is generated using a flexible SAR-GMTI simulator tool, where different systems, modes of operation and scenarios can be easily configured [5], [7], [8].…”

“…From these considerations, this manuscript proposes an optimized SAR mission that maximizes the GMTI performance, keeping low system complexity in terms of receiving channels and hence data volume to be downloaded. The novel architecture is based on a single monostatic multichannel satellite with non-uniformly spaced receiving antennas, as briefly discussed in [7] and [17]. The objective is to provide subclutter visibility for maritime surveillance of small slowly moving boats.…”