Research On Fast Time-domain Imaging Algorithm Of Bistatic Forward-looking SAR

Forward-looking imaging has great significance and broad application prospects in autonomous landing,battlefield reconnaissance and so on.BiSAR(Bistatic Synthetic Aperture Rada)has flexible configuration,and the transmitting antenna and receiving antenna of bistatic SAR are placed at two platforms.In the appropriate case Bi SAR can accomplish forward-looking imaging which mono-static SAR can't achieve.BP(Back projection)algorithm,as the representative of the SAR time-domain imaging algorithm,has the advantage which is applicable to any configuration compared to frequencydomain imaging algorithm.BP algorithm has large computation,so it is significant to research on bistatic forward-looking SAR fast time-domain imaging algorithm.Focusing on the bistatic forward-looking SAR fast time-domain imaging algorithm,this paper mainly carries on the following work:(1)The echo character and two-dimensional resolution of shift invariant bistatic forward-looking SAR are researched.The work laid the foundation for the analysis and design of the following algorithm.(2)BP algorithm and FFBP(Fast Factorized Back Projection)algorithm of bistatic forward-looking SAR are researched.And the precise imaging of the two algorithms are achieved.(3)FFBP algorithm based on azimuth equal spacing coordinates is proposed.According to the range-doppler-iso,azimuth of sub-image in every step sampled in ground rectangular coordinate instead of local elliptical polar coordinate.Thus,we finished the improvement of the FFBP algorithm in computation.(4)The compensate algorithm of FFBP is researched.We model the moion errors of the transmitter and the receiver.By compensating the phase,we can transform the curved flight trajectory into an ideal straight line.It makes FFBP still effective to curved flight trajectory.(5)A new echo fast simulation algorithm of extended scenes' in time-domain is proposed.Through the combination of the pixels in the extended scene,the interpolation of the echo,the approximation and the superposition operation of the echo.We finished the simulation.In tems of operational,this algorithm is better then traditional timedomain simulation algorithm.The above work is all verified to be feasibility and validity through many simulations.The simulations' results indicate that the algorithms which are analyzed and proved in this paper can do a good job in imaging and echo data simulation of extended scenes.