| In SAR is a new type radar system developed from SAR with all-time and all-weather operating characteristic. It can map the terrain and monitor the surface line by the high-precision digital elevation maps obtained. In SAR gets the phase information by processing two or more different-perspective focused SAR images. The digital elevation map is obtained in a complex way with a lot of procedures and a large amount of calculation. Most of the procedures are implemented without FFT. Once In SAR is processed in real time, the high requirements of the optimization of algorithm, selection of digital chip and realization of algorithm are claimed. This paper researches the realization of In SAR real-time signal process scheme in multi-core DSP TMS320C6678. The main research contents and results are outlined as follows:1. In SAR real-time signal processing algorithm has been studied. With the analysis on key steps of In SAR processing, the influence of SAR images coregistration, phase image pre-filtering and flat phase removal on DEM is illustrated. As a result, a real-time parallel In SAR algorithm is proposed. Combining the multi-core signal processing chip C6678, the thesis introduces a specific real-time processing algorithm design flow with the satisfaction of large calculation.2. The details about In SAR real-time signal process scheme implemented in C6678 have been studied. For the large calculation of In SAR signal processing, TI DSP TMS320C6678 with eight cores is chosen to achieve the real-time processing in parallel. Under the constraint of DMA bus bandwidth, the most efficient data transmission mode is proposed to use the bus bandwidth and reduce the whole time. Two different embodiments are made for the realization of In SAR real-time signal processing system in hardware. Combining the internal architecture with cache mechanism, the advantages and disadvantages of these two programs are compared. At last, according to the storage space and data rate requirements, the choice is made for the best realization of In SAR real-time system in hardware.3. The optimized realization of In SAR real-time signal processing algorithm has been studied. On account of the conclusion of chapter three, multiple rows of data are moved from DDR3 to L2 every time in C6678 for increasing the bandwidth utilization. The comparison of time consuming between two different modes shows the effectiveness of this approach. Considering the limitation of C6678 storage space for phase unwrapping procedure, two different data cut methods are put forward. The pros and cons are represented by two images processed with two methods respectively. Finally, the differences between each DEM dealt with DSP and MATLAB show that the In SAR real-time signal processing scheme mentioned above is timely and effective. |
