本文選題：組合編碼信號 + 隨機序列線性調頻信號�。� 參考：《電子科技大學》2014年碩士論文

【摘要】：本文主要進行了組合編碼信號的波形設計與信號處理方面的研究。波形設計設是雷達系統(tǒng)的關鍵技術之一,直接影響系統(tǒng)的分辨力、測量精度、抑制雜波以及抗干擾等性能。近年以來,隨著數(shù)字處理技術發(fā)展,為新體制探測技術和雷達波形捷變技術應用提供了可能,因為常規(guī)雷達波形樣式各有缺陷,需要研究一種具備豐富碼元資源和良好探測性能的新型波形樣式。首先,介紹了雷達經典理論,如距離分辨率、脈沖壓縮技術、多普勒敏感性等,為本文提供了理論基礎。本文總結了傳統(tǒng)雷達波形的性能特點,以及近年來人們在組合編碼信號設計領域的研究狀況,對現(xiàn)有的組合編碼波形構筑方法進行了歸納總結,并通過數(shù)字仿真分析了常見組合編碼信號性能及優(yōu)缺點。在此基礎上,作者選擇了一種新型隨機序列線性調頻信號波形樣式,并通過數(shù)字仿真分析了其各項信號特征,包括頻譜分布、脈沖壓縮、多普勒敏感,互相關特性。通過研究發(fā)現(xiàn)隨機序列線性調頻信號如采用傳統(tǒng)脈沖壓縮方式,其探測性能上存在缺陷,無法進入實用。為了發(fā)揮隨機序列線性調頻信號的潛力,本文進一步研究了專用處理方法,提出序列重排和分段積累消差兩種新型處理方法,通過數(shù)字處理彌補了隨機序列線性調頻信號的性能缺陷,大幅提升了隨機序列線性調頻信號的探測性能。序列重排處理方法參考了合成孔徑雷達CS算法,在CS算法中,采用頻域校正方法消除了地物回波的距離走動,我們將其引入隨機序列線性調頻信號處理,在信號脈沖壓縮前在頻域進行碼元序列位置移動,將隨機序列線性調頻信號5重構為標準序列線性調頻信號,再進行脈壓處理,從而有效降低了脈壓旁瓣,提高了探測能力。分段積累消差處理方法參考了早期逆合成孔徑雷達處理方法,通過分段處理提高了信號多普勒容限,然后根據(jù)信號分段脈壓后分布特性加入消差處理,大幅降低序列之間的互相關影響,使隨機序列線性調頻信號具備了較高實用性。除此之外,本文還提出一種采用多樣本脈沖壓縮的信號處理思路。利用數(shù)字信號處理能力提升,可以將采集的信號利用多個樣本和相應的處理方法進行脈沖壓縮處理,再對處理結果進行融合處理,充分發(fā)揮各個積累方式的優(yōu)點,獲得優(yōu)化的探測能。本文還設計搭建一個半實物仿真系統(tǒng),通過半實物射頻試驗的方法,驗證隨機序列線性調頻信號的實際性能。仿真實驗的結果證明,通過序列重排和分段積累消差處理算法,隨機序列線性調頻信號可以獲得優(yōu)良的探測性能。最后,對全文進行總結,并展望了隨機序列線性調頻信號在波形捷變技術和新體制探測技術的應用前景。本文的研究成果對開展雷達波形設計的研究具有一定的意義。
[Abstract]:In this paper, the waveform design and signal processing of combined coded signals are studied. Waveform design is one of the key technologies of radar system, which directly affects the system resolution, measurement accuracy, clutter suppression and anti-jamming performance. In recent years, with the development of digital processing technology, it is possible to apply the new system detection technology and radar waveform agile technology, because the conventional radar waveform patterns have their own defects. A new waveform pattern with rich symbol resources and good detection performance needs to be studied. Firstly, the classical theory of radar, such as range resolution, pulse compression, Doppler sensitivity and so on, is introduced, which provides a theoretical basis for this paper. This paper summarizes the characteristics of traditional radar waveforms and the research status in the field of combinatorial coding signal design in recent years, and summarizes the existing methods of constructing combined coding waveforms. The performance, advantages and disadvantages of common combined coded signals are analyzed by digital simulation. On this basis, the author chooses a new type of random sequence LFM signal waveform, and analyzes its signal characteristics by digital simulation, including spectrum distribution, pulse compression, Doppler sensitivity and cross-correlation characteristics. It is found that the detection performance of the LFM signal with random sequence, such as the traditional pulse compression method, is defective and can not be applied. In order to give full play to the potential of random sequence LFM signals, this paper further studies the special processing methods, and proposes two new processing methods, sequence rearrangement and piecewise accumulation cancellation. Digital processing makes up for the performance defect of random sequence linear frequency modulation (LFM) signal and greatly improves the detection performance of random sequence LFM signal. The sequence rearrangement method refers to the synthetic Aperture Radar (SAR) CS algorithm. In the CS algorithm, the range walk of the echo is eliminated by using the frequency domain correction method, which is introduced into the random sequence linear frequency modulation (LFM) signal processing. The position of symbol sequence is moved in the frequency domain before pulse compression. The random sequence LFM signal 5 is reconstructed into a standard sequence LFM signal, and then processed by pulse compression, which effectively reduces the sidelobe of pulse compression and improves the detection ability. The piecewise accumulation cancellation method refers to the early inverse synthetic Aperture Radar processing method. The Doppler tolerance of the signal is improved by the piecewise processing, and then the cancellation process is added according to the distribution characteristics of the signal segments after pulse compression. The cross-correlation between the sequences is greatly reduced, which makes the linear frequency modulation signals of random sequences more practical. In addition, a new method of signal processing using multi-sample pulse compression is proposed. With the improvement of digital signal processing ability, the collected signal can be processed by pulse compression with multiple samples and corresponding processing methods, and then the processing results can be fused to give full play to the advantages of each accumulation mode. The optimized detection energy is obtained. A hardware-in-the-loop simulation system is designed and built in this paper to verify the practical performance of random sequence LFM signals by the method of semi-physical RF test. The simulation results show that the random sequence LFM signal can obtain good detection performance through sequence rearrangement and piecewise accumulation cancellation algorithm. Finally, the application prospect of random sequence linear frequency modulation (LFM) signal in waveform agility and new detection technology is prospected. The research results of this paper have a certain significance for the research of radar waveform design.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN957.51

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相關期刊論文 前1條

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本文編號：1914774