Synthetic Aperture Radar Flight Path Optimization for Resolution and Coverage

Two key components in Synthetic Aperture Radar (SAR) are image resolution and scene coverage. To improve SAR image resolution, one may increase the bandwidth of the system (frequency diversity) or increase the range of aspect angles to view the target (geometric diversity). In most applications, the radar must operate within a fixed and specified frequency band, so increasing the frequency diversity is not feasible. To exploit geometric diversity and maximize scene coverage, one may fly around the target scene of interest in a non-straight path and steer the radar antenna towards the desired targets. This leads to a hybrid SAR mode that combines stripmap SAR and spotlight SAR modes. To investigate the trade-off between resolution and coverage, we develop a mathematical tool to quantify the attainable resolution of the target scene by incorporating the data-collection manifold (DCM). We use the DCM to build an objective function that is used as a means for determining optimal flight paths for desired coverage and resolution objectives by varying a SAR vehicle's heading, pitch, and antenna steering angles.