With The Shift To Change The Characteristics Of The Star-union Bistatic Sar Imaging Processing Algorithms

Spaceborne-Airborne Bistatic SAR (SA-BiSAR), which is a new Bistatic SAR composed by the spacecraft and aircraft, not only inherit many advantages of BiSAR, but also demonstrate some unique advantages, such as expanding the scope of target scene, saving the costs of data acquisition, and so on. As being a typical translational variant BiSAR, SA-BiSAR has become a new hotspot in radar imaging application research. In this dissertation, basing on the characteristics of SA-BiSAR, the imaging algorithm of the system has been focused on, and the main research and contributions are as follows:1. The SA-BiSAR system is studied: Establish the general geometry and signal models of SA-BiSAR firstly, and base on these, the range history and the range cell migration (RCM) are disgussed. Then based on the characteristics of the System model, the range history has been approximated sensibly. At last, the spatial resolutions of bistatic SAR have been derived from the ambiguity function.2. An imaging algorithm for SA-BiSAR with any flight mode is proposed. First, use the range history approximated of SA-BiSAR to derivate the Doppler parameter suitably for SA-BiSAR system, which is the key point to the focus of the imaging algorithm basing on the Dimension-reduction Focus. Then use the Inverse-Projection method to correct distortion basing on the formula of final focus expression.3. Analysis the causes of the distortion, which appears after the Dimension-reduction Focus. Thus a geometric correction method for correction distortion is proposed. This method can quickly complete the distortion correction and compensate for the slower processing speed weaknesses of the Inverse-Projection method.4. The LBF model and ELBF model have been detailedly studied. Being the most representative methods of solving two-dimensional spectrum for translational variant BiSAR currently, they are combined with 2-D ISFFT imaging algorithm in this dissertation, and have been compared the imaging results by MATLAB simulation. Basing on the reasonable approximation of range history, an imaging algorithm in two-dimensional frequency-domain is proposed for SA-BiSAR system. The key point of this algorithm is getting the two-dimensional spectrum basing on the inherent characteristics of SA-BiSAR system and the Expression of the range history. Then combined with the reference function multiplication (RFM), and the stolt interpolation to complete imaging method.