Long-CPI MIMO SAR Based GMTI

The problem of detecting ground moving targets with arbitrary linear motion using an airborne multiple-input multiple-output (MIMO) radar is considered. The proposed approach leverages a long coherent processing interval (CPI), and maximizes the moving target signal energy via matching the target's azimuthal signature. The algorithm forms SAR images focused to different hypothesized along-track target velocities, and then uses the MIMO array to detect moving targets in these images. The use of a MIMO array enhances the system's GMTI performance without requiring additional physical channels via the virtual array concept. By reparametrizing the target's linear motion profile, the SAR image formation process can be decoupled from the MIMO array processing, allowing for efficient implementation of the algorithm. Because the approach generates estimates of the target's along-track and cross-track velocity components, a unique determination of the target's motion parameters is possible. The approach is derived, and investigated via simulated data.