Interest in Bistatic and Multistatic SAR (Synthetic Aperture Radar) systems has grown in the last decade. They bring additional benefits to conventional monostatic SAR systems, such as flexibility, cost reduction, reduced vulnerability, etc. At the same time, processing complexity for bistatic configurations is much higher than for conventional monostatic processors. Until now only some numerical and intuitive solutions were given in this respect. No analytical solution is available.
In this work we will focus on bistatic SAR processing problems. The algorithms we will develop are based on a point target reference spectrum derived at our research institute. In the beginning we will derive the bistatic formula itself, which contains quite lengthy and complex mathematical expressions. In the derivation, some approximations are used. We will therefore consider the constraints of validity. Later, we will demonstrate the performance of the bistatic formula with simulation by focusing the single and group of point targets.
In the very general arbitrary configuration, the processing is range and azimuth time dependent. We will focus on increased complexity configurations. In this respect, we will first consider the Tandem case and the translationally invariant case. Later, we will extend the focusing task to the general case, which is the most challenging bistatic configuration. This will be accomplished by compensating the scaling in both range and azimuth directions. Here, transmitter and receiver are moving on non-parallel trajectories with non-equal velocities. We will see that azimuth time variance causes additional scaling of Doppler frequency. As the first approximation, the focusing of the general bistatic SAR will be solved by separating the scaling in range and azimuth frequency directions.
Some modules of our current bistatic algorithm will be substituted later by a truly 2D scaling approach. We will derive the 2D Inverse Scaling approach and show some focusing results obtained from simulated raw data.