FM Signal Pulse Compression On FPGA

Pulse compression technology has been widely used in the modern pulse radar system. Pulse compression technique solves the problem of the single frequency pulse radar can not take into account the range resolution and the radar maximum detection range.Pulse compression technique needs the transmitted signal to obtain the wide band width product by frequency modulation(FM) or phase modulation(PM), and then get a narrow pulse through a matched filtering at the receiving end. In the FM signals, the study of linear frequency modulation(LFM) signal has been started early and widely used in all kinds of pulse radar. One of the major problems of LFM signal is that the high side lobe after pulse compression needs to be suppressed by the weighted network, which will lead to the problem of the main lobe broadening and the loss of the signal to noise ratio. Nonlinear frequency modulated(NLFM) signal is a hot research topic in recent years. It does not need a weighted network, directly through the pulse compression can get a lower side lobe, so as to avoid the problem of loss of signal to noise ratio and so on.This paper bases on the research and development of a multi-function emplacement reconnaissance radar, and the theoretical analysis of the pulse compression system and the realization of FPGA in the radar are introduced. The design and implementation of NLFM signal are mainly researched. In this paper, we also analyze and simulate the performance of pulse compression of the LFM signal and NLFM signal, and discuss some of the problems encountered in practical application. For practical applications to achieve, the principle and method of design and the verify of results for the FPGA design of the AD Acquisition, the Digital Down Converter, and the Pulse Compression are mainly introduced. For the problems met in practical application such as the false alarm in short distance, the simulation analyses are did and the solutions are made, and the program realization is proved to be correct and effect by firing range after the system implementation.