雷達(dá)偵察中LFMCW信號(hào)檢測(cè)與參數(shù)估計(jì)方法研究
發(fā)布時(shí)間：2018-07-18 08:52
【摘要】：線性調(diào)頻連續(xù)波(Linear Frequency Modulated Continuous Wave,LFMCW)雷達(dá)由于結(jié)構(gòu)簡(jiǎn)單、體積小、距離分辨率高、無距離盲區(qū)、成本低、低功耗和低截獲等優(yōu)點(diǎn),在軍用導(dǎo)航、戰(zhàn)場(chǎng)偵察與地面成像等領(lǐng)域得到越來越廣泛的應(yīng)用。由于采用連續(xù)波體制,LFMCW雷達(dá)的發(fā)射功率相比于脈沖多普勒雷達(dá)具有更低的發(fā)射功率,這就導(dǎo)致更低的信噪比,進(jìn)而需要更多的采樣點(diǎn)數(shù)保證信號(hào)檢測(cè)的有效性,因此,高計(jì)算復(fù)雜度和低信噪比成為制約LFMCW信號(hào)有效檢測(cè)和參數(shù)估計(jì)的主要因素。降低計(jì)算復(fù)雜度和提高信噪比成為了LFMCW信號(hào)檢測(cè)與參數(shù)估計(jì)的核心和關(guān)鍵。本論文從信號(hào)處理的角度出發(fā),對(duì)LFMCW信號(hào)的模型、檢測(cè)和參數(shù)估計(jì)等方面做了比較全面的分析和闡述。主要工作概括如下:1.研究了單分量周期LFMCW信號(hào)的檢測(cè)和參數(shù)估計(jì)方法。首先介紹了兩種常用的LFMCW信號(hào)的發(fā)射模型及其截獲模型;然后,針對(duì)低信噪比和高計(jì)算復(fù)雜度的問題,提出一種聯(lián)合變窗長(zhǎng)相干平均法、循環(huán)平穩(wěn)法和解線頻調(diào)處理的單分量周期LFMCW信號(hào)的檢測(cè)與參數(shù)估計(jì)方法。該方法首先基于信號(hào)的周期性,利用變窗長(zhǎng)相干平均法和循環(huán)平穩(wěn)法提高了信噪比增益并實(shí)現(xiàn)了調(diào)制周期和調(diào)頻率的估計(jì),然后基于估計(jì)的調(diào)制周期和調(diào)頻率,利用解線頻調(diào)處理完成了起始頻率、起始時(shí)間、幅度和初相的估計(jì)。該方法以較低計(jì)算復(fù)雜度實(shí)現(xiàn)了長(zhǎng)時(shí)間積累,并有效地提高了信噪比。然而,該方法的檢測(cè)性能受窗長(zhǎng)搜索范圍的制約。針對(duì)該問題,進(jìn)一步提出了改進(jìn)的方法。改進(jìn)的方法首先對(duì)變窗長(zhǎng)相干平均法進(jìn)行了改進(jìn),然后利用改進(jìn)的變窗長(zhǎng)相干平均法和循環(huán)平穩(wěn)法估計(jì)調(diào)制周期和調(diào)頻率,最后,利用解線頻調(diào)處理實(shí)現(xiàn)了起始頻率、起始時(shí)間、幅度和初相的估計(jì)。改進(jìn)方法的檢測(cè)性能不再受搜索窗長(zhǎng)的制約,并且仍以較低計(jì)算復(fù)雜度實(shí)現(xiàn)了長(zhǎng)時(shí)間積累,有效地提高了信噪比。仿真實(shí)驗(yàn)驗(yàn)證了所提方法的有效性。2.研究了多分量周期LFMCW信號(hào)的檢測(cè)和參數(shù)估計(jì)方法。針對(duì)在低信噪比條件下如何快速實(shí)現(xiàn)多分量周期LFMCW信號(hào)的檢測(cè)和估計(jì)問題,提出了一種聯(lián)合幀間相關(guān)法、循環(huán)平穩(wěn)法和解線頻調(diào)處理的多分量周期LFMCW信號(hào)的檢測(cè)與參數(shù)估計(jì)方法。該方法首先基于信號(hào)的周期性,提出一種幀間相關(guān)法及其等價(jià)形式,幀間相關(guān)法及其等價(jià)形式只需簡(jiǎn)單的復(fù)乘和復(fù)加就可實(shí)現(xiàn)多分量信號(hào)能量的線性疊加;其次,根據(jù)幀間相關(guān)法的線性疊加的特點(diǎn),提出一種目標(biāo)剝離方法,目標(biāo)剝離方法可以將多分量LFMCW信號(hào)的調(diào)制周期依次估計(jì)出來,并實(shí)現(xiàn)各信號(hào)分量的檢測(cè);然后,基于CLEAN算法的思想并結(jié)合各信號(hào)分量的調(diào)制周期的估計(jì),利用循環(huán)平穩(wěn)法和解線頻調(diào)處理依次將各信號(hào)分量的幅度、調(diào)頻率、起始頻率、起始時(shí)間和初相估計(jì)出來。所提方法以較低計(jì)算復(fù)雜度實(shí)現(xiàn)了信號(hào)的長(zhǎng)時(shí)間積累,有效地提高了信噪比,并且無需二維峰值搜索就可實(shí)現(xiàn)各信號(hào)分量的檢測(cè),因此計(jì)算量比較小。仿真實(shí)驗(yàn)驗(yàn)證了所提方法的有效性。3.針對(duì)在低信噪比下如何快速實(shí)現(xiàn)LFMCW信號(hào)的檢測(cè)和參數(shù)估計(jì)的問題,提出了一種聯(lián)合零頻搜索法、循環(huán)平穩(wěn)法和解線頻調(diào)處理的LFMCW信號(hào)的檢測(cè)與參數(shù)估計(jì)方法。該方法首先基于LFMCW信號(hào)的瞬時(shí)相關(guān)特性,給出了一種零頻搜索法,零頻搜索法可以實(shí)現(xiàn)信號(hào)的檢測(cè)和調(diào)制周期的估計(jì);其次,針對(duì)零頻搜索法計(jì)算量大的問題,對(duì)其進(jìn)行了改進(jìn),改進(jìn)后的零頻搜索法在保持相同檢測(cè)性能的基礎(chǔ)上有效地減小了計(jì)算量;然后,結(jié)合信號(hào)的調(diào)制周期,利用循環(huán)平穩(wěn)法實(shí)現(xiàn)了信號(hào)調(diào)頻率的估計(jì);最后,基于調(diào)制周期和調(diào)頻率,利用解線頻調(diào)處理估計(jì)信號(hào)幅度、起始時(shí)間、起始頻率和初相。所提方法以較低計(jì)算復(fù)雜度實(shí)現(xiàn)了信號(hào)的長(zhǎng)時(shí)間積累,有效地提高了信噪比。此外,所提方法可以對(duì)符合一定限制條件的多分量LFMCW信號(hào)進(jìn)行檢測(cè)與參數(shù)估計(jì)。仿真實(shí)驗(yàn)驗(yàn)證了所提方法的有效性。4.針對(duì)LFMCW信號(hào)檢測(cè)與參數(shù)估計(jì)所面臨的高計(jì)算復(fù)雜度和低信噪比的問題,提出了一種基于匹配幀間相關(guān)法、循環(huán)平穩(wěn)法和解線頻調(diào)處理的LFMCW信號(hào)的檢測(cè)與參數(shù)估計(jì)方法。該方法首先基于LFMCW信號(hào)周期間的固有規(guī)律,給出了一種匹配幀間相關(guān)法,匹配幀間相關(guān)法可以根據(jù)各信號(hào)分量的調(diào)制周期和起始頻率的不同實(shí)現(xiàn)其檢測(cè)和調(diào)制周期的估計(jì);然后,基于CLEAN算法的思想并結(jié)合各信號(hào)分量的調(diào)制周期的估計(jì),按照信號(hào)幅度由大到小的順序,利用循環(huán)平穩(wěn)法和解線頻調(diào)處理實(shí)現(xiàn)了各信號(hào)分量的調(diào)頻率、起始時(shí)間、起始頻率、初相和幅度的估計(jì)。該方法可在較低的信噪比下對(duì)LFMCW信號(hào)進(jìn)行有效的檢測(cè)和參數(shù)估計(jì),其運(yùn)算復(fù)雜度低,利于工程實(shí)現(xiàn)。仿真實(shí)驗(yàn)驗(yàn)證了所提方法的有效性。
[Abstract]:Linear Frequency Modulated Continuous Wave (LFMCW) radar is becoming more and more widely used in military navigation, battlefield reconnaissance and ground imaging because of its advantages of simple structure, small size, high distance resolution, low distance blind area, low cost, low power consumption and low interception. The application of continuous wave system, LFMCW The transmission power of radar has lower transmission power than that of pulse Doppler radar, which leads to lower signal to noise ratio and more sampling points to ensure the effectiveness of signal detection. Therefore, high computational complexity and low signal to noise ratio become the main factors that restrict the effective detection and parameter estimation of LFMCW signals. Degree and enhancement of signal to noise ratio have become the core and key of LFMCW signal detection and parameter estimation. From the angle of signal processing, this paper makes a comprehensive analysis and exposition of the LFMCW signal model, detection and parameter estimation. The main work is summarized as follows: 1. the detection and parameter estimation of single component periodic LFMCW signal are studied. Methods. First, two kinds of common LFMCW signal emission models and their intercept models are introduced. Then, for low signal to noise ratio and high computing complexity, a method of detection and parameter estimation of single component periodic LFMCW signals with a joint variable window long phase mean method, a cyclostationary method and a line frequency modulation is proposed. The signal's periodicity is used to improve the signal to noise ratio gain and estimate the modulation period and frequency modulation by using the variable window length average method and the cyclostationary method. Then based on the estimated modulation period and frequency modulation, the initial frequency, the starting time, the amplitude and the initial phase are estimated by the frequency modulation of the solution. A long time accumulation is realized and the signal to noise ratio is improved effectively. However, the detection performance of the method is restricted by the scope of the window length search. In view of the problem, an improved method is proposed. The improved method first improves the dry average method of the variable window, and then uses the improved variable window length average method and the cyclostationary method. The modulation period and frequency modulation are estimated. Finally, the initial frequency, the starting time, the amplitude and the initial phase are estimated by the line frequency modulation. The detection performance of the improved method is no longer restricted by the length of the search window, and the long time accumulation is realized with the lower computational complexity, and the signal to noise ratio is improved effectively. The simulation experiment verifies the proposed method. .2. studies the detection and parameter estimation methods of multicomponent periodic LFMCW signals. Aiming at how to quickly realize the detection and estimation of multicomponent periodic LFMCW signals under low signal to noise ratio, a joint inter frame correlation method, the detection and reference of multicomponent periodic LFMCW signals with cyclic stationary and line frequency modulation are proposed. The method of number estimation is based on the periodicity of the signal, and a frame correlation method and its equivalent form are proposed. The interframe correlation method and its equivalent form only need simple complex multiplying and adding to realize the linear superposition of the multicomponent signal energy. Secondly, a target stripping method is proposed according to the linear superposition of interframe correlation method. The target stripping method can estimate the modulation period of the multicomponent LFMCW signal in turn and realize the detection of the signal components. Then, based on the thought of the CLEAN algorithm and the estimation of the modulation period of each signal component, the amplitude, frequency modulation rate and starting frequency of each signal component are sequentially used by the cyclostationary method and the line frequency modulation. The initial time and initial phase are estimated. The proposed method achieves long time accumulation of signals with a lower computational complexity, effectively improves the signal to noise ratio and does not need a two-dimensional peak search to detect the signal components, so the computation is relatively small. The simulation experiment shows how the effectiveness of the proposed method.3. is directed against the low signal to noise ratio. In order to quickly realize the detection and parameter estimation of LFMCW signals, a method of detection and parameter estimation of LFMCW signals combined with zero frequency search, cyclostationary and line frequency modulation is proposed. Firstly, based on the instantaneous correlation characteristic of LFMCW signal, a zero frequency search method is given, and the zero frequency search method can be used to detect the signal. The estimate and modulation period are estimated. Secondly, in view of the problem of large computation of zero frequency search method, it has been improved. The improved zero frequency search method effectively reduces the computation on the basis of maintaining the same detection performance. Then, combining the modulation period of the signal, the estimation of the signal frequency modulation is realized by using the cyclostationary method. Finally, based on the signal modulation method, the method is used to estimate the frequency of the signal. The modulation period and frequency modulation are used to estimate the amplitude, starting time, starting frequency and initial phase by the frequency modulation of the solution line. The proposed method realizes the long time accumulation of the signal with a lower computational complexity and improves the signal to noise ratio effectively. Furthermore, the proposed method can detect and parameter the multicomponent LFMCW signals which are in accordance with certain limit conditions. It is estimated that the effectiveness of the proposed method.4. is based on the problem of high computing complexity and low signal to noise ratio facing LFMCW signal detection and parameter estimation, and a method of detection and parameter estimation of LFMCW signals based on matched frame correlation, cyclostationary and line frequency modulation is proposed. The method is based on LFMCW first. A matching frame correlation method is given, which can be used to estimate the detection and modulation period according to the modulation period and starting frequency of each signal component. Then, the idea based on the CLEAN algorithm and the estimation of the modulation period of each signal component are based on the amplitude of the signal. In the order of large to small, the frequency modulation rate, starting time, starting frequency and initial phase and amplitude of the signal components are estimated by using the cyclostationary method and the line frequency modulation. The method can detect and estimate the LFMCW signal effectively at a low signal to noise ratio, and its operation complexity is low and it is beneficial to the project. The simulation experiment is proved to be good. The effectiveness of the proposed method.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN957.51
本文編號(hào)：2131392
[Abstract]:Linear Frequency Modulated Continuous Wave (LFMCW) radar is becoming more and more widely used in military navigation, battlefield reconnaissance and ground imaging because of its advantages of simple structure, small size, high distance resolution, low distance blind area, low cost, low power consumption and low interception. The application of continuous wave system, LFMCW The transmission power of radar has lower transmission power than that of pulse Doppler radar, which leads to lower signal to noise ratio and more sampling points to ensure the effectiveness of signal detection. Therefore, high computational complexity and low signal to noise ratio become the main factors that restrict the effective detection and parameter estimation of LFMCW signals. Degree and enhancement of signal to noise ratio have become the core and key of LFMCW signal detection and parameter estimation. From the angle of signal processing, this paper makes a comprehensive analysis and exposition of the LFMCW signal model, detection and parameter estimation. The main work is summarized as follows: 1. the detection and parameter estimation of single component periodic LFMCW signal are studied. Methods. First, two kinds of common LFMCW signal emission models and their intercept models are introduced. Then, for low signal to noise ratio and high computing complexity, a method of detection and parameter estimation of single component periodic LFMCW signals with a joint variable window long phase mean method, a cyclostationary method and a line frequency modulation is proposed. The signal's periodicity is used to improve the signal to noise ratio gain and estimate the modulation period and frequency modulation by using the variable window length average method and the cyclostationary method. Then based on the estimated modulation period and frequency modulation, the initial frequency, the starting time, the amplitude and the initial phase are estimated by the frequency modulation of the solution. A long time accumulation is realized and the signal to noise ratio is improved effectively. However, the detection performance of the method is restricted by the scope of the window length search. In view of the problem, an improved method is proposed. The improved method first improves the dry average method of the variable window, and then uses the improved variable window length average method and the cyclostationary method. The modulation period and frequency modulation are estimated. Finally, the initial frequency, the starting time, the amplitude and the initial phase are estimated by the line frequency modulation. The detection performance of the improved method is no longer restricted by the length of the search window, and the long time accumulation is realized with the lower computational complexity, and the signal to noise ratio is improved effectively. The simulation experiment verifies the proposed method. .2. studies the detection and parameter estimation methods of multicomponent periodic LFMCW signals. Aiming at how to quickly realize the detection and estimation of multicomponent periodic LFMCW signals under low signal to noise ratio, a joint inter frame correlation method, the detection and reference of multicomponent periodic LFMCW signals with cyclic stationary and line frequency modulation are proposed. The method of number estimation is based on the periodicity of the signal, and a frame correlation method and its equivalent form are proposed. The interframe correlation method and its equivalent form only need simple complex multiplying and adding to realize the linear superposition of the multicomponent signal energy. Secondly, a target stripping method is proposed according to the linear superposition of interframe correlation method. The target stripping method can estimate the modulation period of the multicomponent LFMCW signal in turn and realize the detection of the signal components. Then, based on the thought of the CLEAN algorithm and the estimation of the modulation period of each signal component, the amplitude, frequency modulation rate and starting frequency of each signal component are sequentially used by the cyclostationary method and the line frequency modulation. The initial time and initial phase are estimated. The proposed method achieves long time accumulation of signals with a lower computational complexity, effectively improves the signal to noise ratio and does not need a two-dimensional peak search to detect the signal components, so the computation is relatively small. The simulation experiment shows how the effectiveness of the proposed method.3. is directed against the low signal to noise ratio. In order to quickly realize the detection and parameter estimation of LFMCW signals, a method of detection and parameter estimation of LFMCW signals combined with zero frequency search, cyclostationary and line frequency modulation is proposed. Firstly, based on the instantaneous correlation characteristic of LFMCW signal, a zero frequency search method is given, and the zero frequency search method can be used to detect the signal. The estimate and modulation period are estimated. Secondly, in view of the problem of large computation of zero frequency search method, it has been improved. The improved zero frequency search method effectively reduces the computation on the basis of maintaining the same detection performance. Then, combining the modulation period of the signal, the estimation of the signal frequency modulation is realized by using the cyclostationary method. Finally, based on the signal modulation method, the method is used to estimate the frequency of the signal. The modulation period and frequency modulation are used to estimate the amplitude, starting time, starting frequency and initial phase by the frequency modulation of the solution line. The proposed method realizes the long time accumulation of the signal with a lower computational complexity and improves the signal to noise ratio effectively. Furthermore, the proposed method can detect and parameter the multicomponent LFMCW signals which are in accordance with certain limit conditions. It is estimated that the effectiveness of the proposed method.4. is based on the problem of high computing complexity and low signal to noise ratio facing LFMCW signal detection and parameter estimation, and a method of detection and parameter estimation of LFMCW signals based on matched frame correlation, cyclostationary and line frequency modulation is proposed. The method is based on LFMCW first. A matching frame correlation method is given, which can be used to estimate the detection and modulation period according to the modulation period and starting frequency of each signal component. Then, the idea based on the CLEAN algorithm and the estimation of the modulation period of each signal component are based on the amplitude of the signal. In the order of large to small, the frequency modulation rate, starting time, starting frequency and initial phase and amplitude of the signal components are estimated by using the cyclostationary method and the line frequency modulation. The method can detect and estimate the LFMCW signal effectively at a low signal to noise ratio, and its operation complexity is low and it is beneficial to the project. The simulation experiment is proved to be good. The effectiveness of the proposed method.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN957.51
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