A novel two-dimensional spectrum for bistatic SAR processing based on range equation approximation

The frequency spectrum expression plays a key role In bistatic SAR image formation. However, due to the existence of double-square-roots in the bistatic range equation, it is difficult to obtain an analytical two-dimensional spectrum. This paper derives a novel spectrum expression for bistatic SAR processing. Based on the appropriate approximation, the original range equation with double-square-roots form can be approximated as the sum of a linear function and a single square-root. Thus the analytical stationary point and spectrum expression can be calculated according the principle of stationary phase. Finally, numerical simulations are performed to validate the proposed frequency spectrum.