Study On The Technique Of Digital Pulse Compression For Multi-waveforms Based On DSP

Pulse compression (PC) technique has been widely used in modern radar systems, to resolve the contradiction between the distance and resolution. Pulse compression technique includes two key techniques: the pulse compression signal generation and processing. Digital pulse compression processing can be divided into pulse compression processing in time domain and pulse compression processing in frequency domain. With the development of high performance digital signal processor and high speed real time signal processing techniques, pulse compression processing technique in frequency domain has become an important topic in modern pulse compression system.Firstly, the linear frequency modulation signal(LFM) and binary phase-coded signal(BC) are discussed based on the pulse compression basic theory, it is analyzed from the aspects of the spectrum characteristic, the ambiguity function, pulse compression and the Doppler characteristic. The solution to sidelobe suppression of the LFM and BC signal are discussed in details. For LFM signal, the method of employing Hamming weighting is demonstrated; for binary coded signal, the application of optimal peak sidelobe level(PSL) mismatched filtering algorithm is discussed.Secondly, the the design and solution of two hybrid radar signals composed of LFM and BC signals are analyzed. The co-modulated signals have better performance compared to single modulation mode. Though theoretical analysis and computer simulation, the spectrum characteristic, ambiguity function and resolution are discussed. The simulation results show that these hybrid signals are low probability of intercept radar signals. However, conventional window function is not effective for sidelobe suppression because of the signals particularity. So network synthesis is adopted to restrain sidelobe and the results are quite good.Lastly, the high precision digital pulse compression system in frequency domain based on general DSP is introduced. The test of some experimental result of linear frequency modulation, binary phase code and two types of hybrid radar signals are accomplished, on a signal processing board base on TMS320C6713. Experimental results confirmed that this system meets the requirements of the practical radar systems, and the two hybrid radar signals are easy to be produced and able to be realized in engineering.