Double Base Before, As The Sar Doppler Parameter Estimation Algorithm

Forward-looking imaging has many potential applications, but it is impossible with the usual monostatic synthetic aperture radar (SAR). This defect can be offset by the bistatic forward-looking SAR which uses the side-looking transmitter and the forward-looking receiver. The bistatic forward-looking SAR has the capability of flexibly beam direction, high security and countering vulnerability. Because of these characteristics, it will be widely used in military and civil fields.Doppler parameters estimation is necessary for SAR high-quality image, and the Doppler parameters of bistatic forward-looking SAR is special. Focusing on Doppler parameters estimation, the main work of this thesis is shown as follows:1,Research on two geometrical models of bistatic forward-looking SAR. The characteristics of echo are analyzed. The relationship between the Doppler parameters and perspective of the plats is discussed;2,According to the Doppler centroid of the bistatic forward-looking SAR is big, a Doppler ambiguity number estimation algorithm based on Radon transform is researched; and a baseband Doppler centroid estimation algorithm based on phase is researched. Joint this two, a Doppler centroid estimation algorithm is given;3,The time-frequency rate distribution (TFRD) of polynomial phase signal is researched; the influence of cross term is analyzed; according to the Doppler frequency rate of the bistatic forward-looking SAR is small, a Doppler frequency rate estimation algorithm based on TFRD is given;4,The discrete polynomial-phase transform of polynomial phase signal is researched; a high-precision measurement method of carrier frequency for single frequency signal is analyzed; according to the Doppler cubic term of the bistatic forward-looking SAR is not negligible, a Doppler cubic term estimation algorithm based on discrete polynomial-phase transform is given.