复杂调制LPI雷达信号参数估计算法研究

发布时间：2018-05-30 09:15

本文选题：LPI雷达信号 + 时频分析　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：雷达信号调制方式的复杂化对电子侦察技术提出了更高的要求。目前雷达广泛采用低截获概率(LPI)技术,研究LPI雷达信号的参数估计具有重要的现实意义和应用价值。本文以时频分析为基础,采用不同的算法对LPI雷达信号进行参数估计。本文主要工作和成果如下:首先,介绍了时频分析的基本理论,同时介绍了四种典型的LPI雷达信号,包括二相编码信号、多相编码信号、线性调频与二相编码混合信号、线性调频连续波信号。其次,针对上述四种LPI雷达信号,分别研究了其各自的参数估计算法。针对二相编码信号,采用基于周期模糊函数构造统计量的参数估计算法。选取一组时延向量构造统计量,通过累积作用提高性能,抑制噪声干扰。针对多相编码信号,如果截获的多相编码信号具有完整周期,则采用周期模糊函数估计参数。如果截获的信号不具有完整周期,则结合二次相位函数和模糊函数的参数估计算法。该算法避免了在较低信噪比下无法通过最高值寻找Radon变换后尖峰的问题,提高了参数估计性能。针对线性调频与二相编码混合信号,先采用离散Chirp傅里叶变换(DCFT)对信号进行去噪处理。再对去噪后的信号平方,采用LVD和DCFT估计信号的调频斜率。最后对信号解调,使之变成二相编码信号,采用基于周期模糊函数构造统计量的算法估计信号码速率。通过DCFT去噪算法,提高了后续算法低信噪比下的性能。针对线性调频连续波信号,采用帧间相关法估计信号的周期。对于信号起始存在时延的情况,先采用DCFT估计信号时延,再截取完整周期信号估计载频和调频斜率。
[Abstract]:The complexity of radar signal modulation has put forward higher requirements for electronic reconnaissance technology. At present, low probability of interception (LPI) technique is widely used in radar, and it has important practical significance and application value to study the parameter estimation of LPI radar signal. Based on time-frequency analysis, different algorithms are used to estimate the parameters of LPI radar signal. The main work and achievements are as follows: firstly, the basic theory of time-frequency analysis is introduced, and four typical LPI radar signals are introduced, including binary coded signals, polyphase coded signals, linear frequency modulation and binary coded mixed signals. Linear frequency modulation continuous wave signal. Secondly, for the above four LPI radar signals, their respective parameter estimation algorithms are studied. For binary coded signals, a parameter estimation algorithm based on periodic ambiguity function is proposed. A group of time-delay vectors are selected to construct statistics to improve performance and suppress noise interference through cumulative action. For the polyphase coded signal, if the intercepted polyphase coded signal has a complete period, the parameter is estimated by the periodic ambiguity function. If the intercepted signal does not have a complete period, the parameter estimation algorithm of quadratic phase function and ambiguity function is combined. The algorithm avoids the problem of finding the peak after Radon transform through the highest value in low SNR, and improves the performance of parameter estimation. For the mixed signal of linear frequency modulation and binary phase coding, the discrete Chirp Fourier transform (DFT) is used to Denoise the signal. Then, the frequency modulation slope of the signal is estimated by LVD and DCFT for the signal square after denoising. Finally, the signal is demodulated into a two-phase coded signal, and the algorithm based on the periodic ambiguity function is used to estimate the signal rate. The DCFT denoising algorithm is used to improve the performance of the following algorithm under low signal-to-noise ratio (SNR). For the linear frequency modulation continuous wave signal, the period of the signal is estimated by the method of inter-frame correlation. In the case of signal initial delay, DCFT is used to estimate the signal delay, and then to intercept the complete periodic signal to estimate the carrier frequency and frequency modulation slope.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.51

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