伪码调相中断连续波雷达的信号处理系统设计及FPGA实现

【作者】 赵红伟；

【导师】 谢仁宏；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2012， 硕士

【摘要】 在现代高技术战争中,以雷达为代表的战场感知系统,对战争的胜负起着不可估量的作用。近程地面侦察雷达能够对入侵方的坦克、装甲车辆、步兵等地面活动目标进行全天候的监视。而伪码调相中断连续波雷达结合了脉冲多普勒雷达和伪码调相连续波雷达的优势,克服了连续波雷达发射泄漏的缺点,有效地提升了地面侦察雷达的性能,是国内外研究的热点。论文首先对常用的伪随机码的自相关特性进行了分析,建立了伪码调相中断连续波雷达的目标回波模型,在此基础上仿真分析了伪码调相中断连续波信号的模糊函数图。其次,设计了满足雷达性能要求且适合FPGA实现的信号处理算法,包括数字下变频、杂波抑制、匹配滤波及旁瓣抑制、距离门重排、多普勒滤波、功率谱估计等处理模块,并利用MATLAB仿真工具对处理算法的功能和性能进行了评估。再次,在信号处理硬件平台的Altera EP3SE110上实现了该信号处理算法,并进行了测试。测试表明本文设计的算法可以正确地检测到目标并得到目标的距离、速度、强度等信息。最后,讨论了伪码调相中断连续波雷达的多普勒补偿技术,在对常用的普勒补偿技术分析的基础上,设计实现了基于FPGA的补偿方法,并完成了该方法在信号处理硬件平台上的功能测试,验证了该方法的正确性。更多还原

【Abstract】 Battlefield information acquisition system, including radar, plays an important role in modern high-technology war. Short-range ground reconnaissance radar can monitor enemy moving targets such as tanks, armored vehicles, infantries and so on in all-weather conditions. The pseudo-random coded quasi-continuous wave(QCW) radar, which has the advantage of pulse Doppler radar and pseudo-random coded continuous wave(CW) radar, not only solves the problem of transmit leakage of CW radar, but also improves the detection performance effectively. So pseudo-random coded QCW radar is always the focus of the research work in China and abroad recently.This paper discusses the autocorrelation function of common pseudo-random codes firstly.After building the model of the radar echo signals, the ambiguity function figure of pseudo-random coded QCW radar is shown in the paper. Then a digital signal processing system for the radar based on FPGA is simulated and illustrated in detail to meet its performance requirements. The system consists of digital down converter (DDC), clutter suppression, matched filtering, sidelobe suppression, range-gate permutation and power spectral density estimate. Then the function and performance of the algorithm is evaluated by MATLAB.Next, the implementation of signal processing algorithm in FPGA on the hardware platform based on Altera EP3SE110 is described and the test results are also provided.The experimental data prove that signal processing algorithm mentioned in this paper can detect the existence of moving targets exactly and can obtain relevant information, such as their distance, speed, intensity and so on. Finally, the paper talks about Doppler compensation of pseudo-random coded QCW radar. After introducing the existing method, a Doppler compensation way based on FPGA is designed and implemented and the test results are given to prove the validity of the proposed method.更多还原