Ground moving target detection based on MIMO SAR systems

Multichannel space-based synthetic aperture radar (SAR) systems that exploit receiving antenna subarrays displaced in the along-Track direction have been shown to provide the capability to detect ground moving targets and potentially estimate their radial motion velocity, thus making possible their correct relocation inside the SAR image of the background. However, the use of only two receiving channels to contain cost, mass, and data-rate, imposes limitations in terms of potentiality of joint clutter cancelation and target velocity estimation. To overcome this problem, we propose a full MIMO SAR scheme obtained by transmitting nearly orthogonal waveforms with the two subarrays achieved from a single antenna aperture and receiving with the same subarrays. A complete processing chain for the joint detection, imaging, and radial speed estimation is presented showing that by properly applying the clutter cancelation step before waveform compression, a good clutter removal performance is obtained despite the waveforms are not fully orthogonal. The performance of the proposed MIMO system is deeply investigated and compared to the performance of conventional multichannel systems to assess the relative merits and drawbacks