Application Of Phase Coded Pulse Compression Technology In Radar Applications

Pulse compression signal is a kind of radar signals with large time width and large bandwidth, it solves the problem of simple pulse can also improve the range resolution and radar target detection function. Phase-coded signal is a common pulse compression signal. Phase-coded signal get wide application because of its easy implementation of actual circuit, anti-fading ability, strong anti-interference ability and low probability of intercept. In this paper, the pulse compression system is realized by FPGA chip. Use FPGA chip could reduce equipment size and hardware costs, short development cycles, increase the flexibility and reliability of the system, so it has practical value.This paper first discussed pulse compression technology and related theories. Then it also discussed the property of the Barker code, M code sequence, random sequence code and Taylor code, and their autocorrelation function were simulated by MATLAB. According to the results of simulation, a Taylor code which prototype code is a 35bit-random-code was adopted as the symbols of the Phase-coded signal.In this paper, the main research is the realization method of phase coded pulse compression system based on FPGA project. The program was designed by Xilinx ISE Design Suite 14.4, used VHDL.The specific content is divided into two parts:1) Generate 7.5MHz phase-coded signal. The function module used method of FPGA+DAC, and the digital IF signal used DDWA (direct digital waveform synthesis).This module output a pulse which pulse width is 7μs and carrier frequency is 7.5MHz.2) Digital pulse compression system. This module used method of ADC+FPGA. DDC(Digital Down Convert) was used to convert digital IF signal into baseband I/Q signal, and then the pulse compression processing was realized by time-domain methods. The pulse compression algorithm had a transversal filter structure that can be achieved by using FPGA FIR Core. This module finally get a pulse compression result with a MSLR(Main-to-Side Lobe Ratio)of 17.6dB.This design not only had good performance of MSLR and good performance of common frequency jamming, but also reduced the sensitivity of the Doppler, is a useful pulse compression system.