本文選題：LPI雷達(dá)信號(hào) + 時(shí)頻分析��； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：雷達(dá)信號(hào)調(diào)制方式的復(fù)雜化對(duì)電子偵察技術(shù)提出了更高的要求。目前雷達(dá)廣泛采用低截獲概率(LPI)技術(shù),研究LPI雷達(dá)信號(hào)的參數(shù)估計(jì)具有重要的現(xiàn)實(shí)意義和應(yīng)用價(jià)值。本文以時(shí)頻分析為基礎(chǔ),采用不同的算法對(duì)LPI雷達(dá)信號(hào)進(jìn)行參數(shù)估計(jì)。本文主要工作和成果如下:首先,介紹了時(shí)頻分析的基本理論,同時(shí)介紹了四種典型的LPI雷達(dá)信號(hào),包括二相編碼信號(hào)、多相編碼信號(hào)、線性調(diào)頻與二相編碼混合信號(hào)、線性調(diào)頻連續(xù)波信號(hào)。其次,針對(duì)上述四種LPI雷達(dá)信號(hào),分別研究了其各自的參數(shù)估計(jì)算法。針對(duì)二相編碼信號(hào),采用基于周期模糊函數(shù)構(gòu)造統(tǒng)計(jì)量的參數(shù)估計(jì)算法。選取一組時(shí)延向量構(gòu)造統(tǒng)計(jì)量,通過累積作用提高性能,抑制噪聲干擾。針對(duì)多相編碼信號(hào),如果截獲的多相編碼信號(hào)具有完整周期,則采用周期模糊函數(shù)估計(jì)參數(shù)。如果截獲的信號(hào)不具有完整周期,則結(jié)合二次相位函數(shù)和模糊函數(shù)的參數(shù)估計(jì)算法。該算法避免了在較低信噪比下無法通過最高值尋找Radon變換后尖峰的問題,提高了參數(shù)估計(jì)性能。針對(duì)線性調(diào)頻與二相編碼混合信號(hào),先采用離散Chirp傅里葉變換(DCFT)對(duì)信號(hào)進(jìn)行去噪處理。再對(duì)去噪后的信號(hào)平方,采用LVD和DCFT估計(jì)信號(hào)的調(diào)頻斜率。最后對(duì)信號(hào)解調(diào),使之變成二相編碼信號(hào),采用基于周期模糊函數(shù)構(gòu)造統(tǒng)計(jì)量的算法估計(jì)信號(hào)碼速率。通過DCFT去噪算法,提高了后續(xù)算法低信噪比下的性能。針對(duì)線性調(diào)頻連續(xù)波信號(hào),采用幀間相關(guān)法估計(jì)信號(hào)的周期。對(duì)于信號(hào)起始存在時(shí)延的情況,先采用DCFT估計(jì)信號(hào)時(shí)延,再截取完整周期信號(hào)估計(jì)載頻和調(diào)頻斜率。
[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.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN957.51

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