Radar Target Detection On IF Signal Based On DSP

With the development of maritime transportation, maritime security raises more and more concerns. Marine radar system is one of the main techniques for target detection. In modern marine radar systems, radar data processing subsystem is required to correctly detect the weak echo signals under strong interference, so as to improve the detection rate of the marine radar system.This thesis, depriving from the basic Sci& Tech researching project of "the research of digital processing method of intermediate frequency signal for marine radar " supported by the Ministry of Communication, is mainly researching on the processing method of improving the digital receiver dynamic range of intermediate frequency signal. Usually the radar video signal is used to detect, but it only utilizes the amplitude of the signals and lost the information of phase and frequency of radar signals. In this design, radar signal is sampled at IF and executed DDS, IF signal will become two signals of baseband signal-I/Q, I/Q signals keep all the information of the original signal down, so it can improve the efficiency of the detection.The method of amplitude-phase union is used to detect radar signal. As the envelope of amplitude information of the echo signals can be obtained by the amplitude of down-conversion I/Q signals through some algorithms, so on the amplitude detection, two traditional methods of the video detection are used-Moving window detector,Two-Pole filter. A comparison on system stability, the improving of SNR of two algorithms by Matlab emulation is made.However, when the echo signals are completely overwhelmed by noise, a threshold may not be used to distinguish between target signal and noise, then the echo phase information can be used to obtain the information of object. As the change of the phase of non-target-echo units are different from target-echo units, according this character, a method of phase detection is proposed in this paper-Reference Unit of Comparative Law. And a detailed description of this method is given, and the feasibility is verified by a large number of MATLAB simulation experiments.In the section of the implementation based on DSP, This high-speed four-channel data acquisition board SDZ605 provided by SDRising is used in this design, hardware and software development platform based on DSP which moving window detector,two-pole filter are implement are discussed. And the feasibility of the algorithm is validated by the result of the emulation.