Azimuth-Variant Multi-Antenna SAR Image Formulation Processing
Distributed multi-antenna synthetic aperture radar (SAR), especially bistatic SAR, will play a great role in future remote sensing because of its special advantages. Although bistatic SAR has received much recognition in years, bistatic configurations considered in open literature are primarily azimuth-invariant bistatic SAR. Bistatic SAR systems can be divided into semi-active and fully active configurations. Semi-active configurations combine passive receiver with an active radar illuminator; fully active bistatic SAR uses two conventional radars flying in close formation to acquire bistatic SAR data during a single pass. For bistatic SAR imaging, both of the antennas are steered to obtain an overlapping beam on the ground, and the exposure of a target is governed by this composite beam pattern. An analysis of imaging time and imaging coverage is thus necessary. A space-time diagram-based approach was investigated in, but a rectangular approximation is employed.