SAR Imaging, Receiver and Transmitter at Different Speeds

Synthetic Aperture Radar (SAR) makes possible high-resolution imaging in a variety of contexts. Applications include imaging the Earth’s terrain, monitoring forestry bio-mass, aircraft identifica- tion, etc.

Although it is possible to collect enough data so that SAR images are reliable, it is often not practical to collect and process large amounts of data, especially when the image is needed in (almost) real time. Therefore, it may be the case that just a single sweep (instead of multiple sweeps) over the scene to be imaged is made and image is reconstructed based on this limited data.

It is reasonable to investigate the possibility of obtaining acceptable images using limited data and also, perhaps more importantly, study what artifacts can be expected when such SAR data is processed by conventional backprojection methods. Indeed, the results of our work [1] show that in the case of bistatic SAR, where the transmitter and receiver are moving with equal speed in opposite directions, there are unavoidable artifacts in the reconstructed image of the Earth’s surface.

The current work continues on from [1] by analyzing the situation where the transmitter and receiver are either moving in the same direction or opposite direction and with different speeds. When the transmitter and receiver are moving in the same direction, we show that the scattering operator F that models the SAR data is a Fourier Integral Operator (FIO).