Multi-angle DVB-S based passive ISAR sensitivity to target motion estimation errors

In this work, we consider a multistatic passive radar configuration comprising a DVB-S illuminator of opportunity and multiple receivers on or near the Earth surface for multi-angle passive ISAR imaging. As shadowing effects are greatly reduced by merging the information taken from different viewing angles, the multistatic image can provide a more detailed representation of the target, paving the way forward its classification. Back-Projection Algorithm (BPA) is an appealing focusing tool for such a configuration, since it allows producing the individual images on a common reference plane regardless the different bistatic angles. However, as the exploitation of satellite signals of opportunity entails a poor capability to have an accurate knowledge of the target kinematics, a significant geometry-dependent image distortion is likely experienced, and therefore registration errors among the images must be taken into account. Theoretical and numerical analyses are here provided to measure the impact of errors in the target rotation estimates on the resulting multi-angle passive ISAR images. The analysis is also complemented with a few experimental results, comprising a turning ferry and an Astra satellite.