Imaging method for the extended scene of missile-borne bistatic forward-looking SAR

Due to such problems as high order terms in double square roots and more serious range cell migration than monostatic or bistatic SAR in range history, caused by high velocities and accelerations in both the transmitter and the receiver platforms in a new and special bistatic synthetic aperture radar imaging mode, i.e., missile-borne bistatic forward-looking synthetic aperture radar, an imaging algorithm correcting space variance for the extended scene for is proposed. The range walk is firstly corrected in the time domain to reduce the two dimensional (2D) coupling. And then the space variance of phase terms, in the 2D frequency spectrum of the echo signal with high precision gained by the method of series reversion, is analyzed quantitatively. The imaging is completed through polynomial fitting and variant match filter designing. With simple operation and less computation, our algorithm is convenient for imaging processing and subsequent procedure in the missile-borne platform. Simulation results show our imaging method significantly corrects the space variance, improves the focus quality of fringe targets, and thus extends the imaging scene.