Design Theory And Realization Of Signal Processing System For Spaceborne MMW Radar

In this thesis, a systematic study on the design and realization of signal processing system for spaceborne MMW radar is carried out. Several subjects are discussed, including direct IF signal quadrature sampling , digital pulse compression, moving target detection, and system development.In the introduction, the research background and significance are introduced firstly. Then, the content, the key technology and the tendence of radar digital signal processing are presented. The requirement for the design and realization of spaceborne radar signal peocessing system is stated. Lastly, main work of this thesis is introduced.In the second chapter, after analyzing the merits of IF signal quadrature sampling, different realizations are introduced. According to the requirement of filter design , the possible range and optimal value of sampling frenquency are deduced. Then, based on the rule of weighted least mean square, a new method of designing IF filter is put forward. It has analytic formula and good performance. In the end, using this method an IF signal quadrature sampling system is designed and implemented.In chapter 3, the methods of realizing digital pulse compression are summarized. Then a systematic study on the key technology of implementing digital pulse compression is carried out. A self-defined floating-point data and parallel time-divided butterfly arithmetic unit are presented to get good performance. In the end, a digital pulse compression system is realized using two pieces of FPGA, with large dynamic range, high precision, light weight, short processing time, small bulk and power.In chapter 4, a detecting method based on coherent integrating after compensating envelope migration by median interpolating and shifting sampling is proposed to improve the detection performance of high speed targets. Then, a method of noncoherent integrating is put forward based on frequency divisionand envelope shift to decrease computational complexity. Simulations indicate that the two methods are useful.In chapter 5, after analyzing the structure and key technology of the spaceborne MMW radar signl processing system, a high performance system is designed and implemented using devices including two pieces of TMS320C6701 and FPGA. Two successful outer test indicates that the design theory is correct and the MMW radar signal processing system is useful.In the last chapter, a summary is presented, and the defects are analyzed. At last, the directions for future research are pointed out.