高動(dòng)態(tài)低載噪比信號(hào)的頻率估計(jì)算法研究
發(fā)布時(shí)間：2018-10-26 19:27
【摘要】：為了從高動(dòng)態(tài)環(huán)境中估計(jì)出載噪比極低的目標(biāo)信號(hào)的頻率,國(guó)內(nèi)外開(kāi)展了大量的算法研究,但這些算法的關(guān)注點(diǎn)大都集中在對(duì)恒頻信號(hào)頻率的估計(jì),應(yīng)用環(huán)境的載噪比一般也在30dBHz以上,只有極少數(shù)的文獻(xiàn)研究了載噪比為17~18dBHz的情況。本文針對(duì)極低載噪比的高動(dòng)態(tài)信號(hào),且信號(hào)頻率并不單一,提出了一種捕獲和擬合相結(jié)合的頻率估計(jì)算法,并且保證估計(jì)的精度在5mHz內(nèi)。首先,本文給出了頻率估計(jì)的數(shù)學(xué)模型并且推導(dǎo)了參數(shù)估計(jì)的理論界,給出了其閉合表達(dá)式,為以后的研究提供了理論基礎(chǔ)。然后,本文介紹了恒頻估計(jì)和變頻估計(jì)的算法,針對(duì)恒頻估計(jì),主要介紹了基于FFT的頻率估計(jì)算法,并且給出了不同算法的仿真性能對(duì)比;針對(duì)變頻估計(jì)主要介紹了時(shí)域分析方法、基于極大似然估計(jì)和含預(yù)處理的FFT算法,仿真分析發(fā)現(xiàn)時(shí)域匹配周期圖算法在實(shí)際中性能較優(yōu);最后,通過(guò)前面對(duì)恒頻估計(jì)算法的分析,總結(jié)出了最優(yōu)的恒頻估計(jì)算法,并將其應(yīng)用于對(duì)變頻信號(hào)的估計(jì),仿真驗(yàn)證了其在高載噪比時(shí)具有較好的性能;對(duì)于低載噪比高動(dòng)態(tài)信號(hào)的頻率估計(jì),本文提出了新的高精度估計(jì)算法,由捕獲模塊和擬合模塊兩部分組成,捕獲模塊中包括兩次捕獲操作,主要是根據(jù)時(shí)域匹配周期圖算法改進(jìn)而來(lái),通過(guò)設(shè)置遞減的變化率步長(zhǎng),確定信號(hào)變化率的范圍,最終可將其變化率降到0.1Hz/s以下,實(shí)現(xiàn)對(duì)信號(hào)的抓捕,同時(shí)給出了最優(yōu)捕獲的參數(shù)設(shè)置;擬合模塊是對(duì)頻率估計(jì)精度的進(jìn)一步提升,將捕獲得到的信號(hào)看作是恒頻信號(hào),然后采用傅里葉插值的頻率估計(jì)算法進(jìn)行估計(jì)和線性擬合,其中也包括兩次擬合操作,最終該算法在載噪比為11dBHz以上,并且頻率變化率范圍為[-3kHz/s,3kHz/s]的信號(hào)中,估計(jì)精度達(dá)到5mHz的要求。
[Abstract]:In order to estimate the frequency of target signal with very low carrier to noise ratio from high dynamic environment, a large number of algorithms have been studied at home and abroad, but the focus of these algorithms is mostly on the estimation of frequency of constant frequency signal. The carrier noise ratio of the applied environment is generally above 30dBHz, and only a few literatures have studied the case where the carrier noise ratio is 17~18dBHz. In this paper, a frequency estimation algorithm combining acquisition and fitting is proposed for high dynamic signals with very low carrier / noise ratio and the signal frequency is not single, and the accuracy of the estimation is guaranteed in 5mHz. First of all, the mathematical model of frequency estimation is given, and the theoretical bound of parameter estimation is derived, and the closed expression is given, which provides a theoretical basis for further research. Then, this paper introduces the algorithms of constant frequency estimation and frequency conversion estimation. For constant frequency estimation, the frequency estimation algorithm based on FFT is mainly introduced, and the simulation performance of different algorithms is compared. Based on the maximum likelihood estimation (MLE) and the FFT algorithm with preprocessing, the simulation results show that the time-domain matching periodic graph algorithm has better performance in practice. Finally, through the analysis of the previous constant frequency estimation algorithm, the optimal constant frequency estimation algorithm is summarized, and it is applied to the frequency conversion signal estimation. The simulation results show that the algorithm has better performance when the load / noise ratio is high. For the frequency estimation of low load to noise ratio and high dynamic signal, a new high precision estimation algorithm is proposed in this paper, which consists of two parts: acquisition module and fitting module. The capture module includes two acquisition operations. It is mainly improved according to time-domain matching period diagram algorithm. By setting the decreasing rate of change step size, the range of signal change rate can be determined, and finally its change rate can be reduced below 0.1Hz/s to realize the capture of the signal. At the same time, the parameter setting of the optimal capture is given. The fitting module is a further improvement of the accuracy of frequency estimation. The captured signal is regarded as a constant frequency signal, and then the frequency estimation algorithm based on Fourier interpolation is used to estimate and linear fit, which also includes two fitting operations. Finally, the estimation accuracy of the proposed algorithm is up to the requirement of 5mHz when the carrier noise ratio is above 11dBHz and the frequency change rate is in the range of-3 kHz / s ~ 3 kHz / s.
【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)】：TN911.23
本文編號(hào)：2296721
[Abstract]:In order to estimate the frequency of target signal with very low carrier to noise ratio from high dynamic environment, a large number of algorithms have been studied at home and abroad, but the focus of these algorithms is mostly on the estimation of frequency of constant frequency signal. The carrier noise ratio of the applied environment is generally above 30dBHz, and only a few literatures have studied the case where the carrier noise ratio is 17~18dBHz. In this paper, a frequency estimation algorithm combining acquisition and fitting is proposed for high dynamic signals with very low carrier / noise ratio and the signal frequency is not single, and the accuracy of the estimation is guaranteed in 5mHz. First of all, the mathematical model of frequency estimation is given, and the theoretical bound of parameter estimation is derived, and the closed expression is given, which provides a theoretical basis for further research. Then, this paper introduces the algorithms of constant frequency estimation and frequency conversion estimation. For constant frequency estimation, the frequency estimation algorithm based on FFT is mainly introduced, and the simulation performance of different algorithms is compared. Based on the maximum likelihood estimation (MLE) and the FFT algorithm with preprocessing, the simulation results show that the time-domain matching periodic graph algorithm has better performance in practice. Finally, through the analysis of the previous constant frequency estimation algorithm, the optimal constant frequency estimation algorithm is summarized, and it is applied to the frequency conversion signal estimation. The simulation results show that the algorithm has better performance when the load / noise ratio is high. For the frequency estimation of low load to noise ratio and high dynamic signal, a new high precision estimation algorithm is proposed in this paper, which consists of two parts: acquisition module and fitting module. The capture module includes two acquisition operations. It is mainly improved according to time-domain matching period diagram algorithm. By setting the decreasing rate of change step size, the range of signal change rate can be determined, and finally its change rate can be reduced below 0.1Hz/s to realize the capture of the signal. At the same time, the parameter setting of the optimal capture is given. The fitting module is a further improvement of the accuracy of frequency estimation. The captured signal is regarded as a constant frequency signal, and then the frequency estimation algorithm based on Fourier interpolation is used to estimate and linear fit, which also includes two fitting operations. Finally, the estimation accuracy of the proposed algorithm is up to the requirement of 5mHz when the carrier noise ratio is above 11dBHz and the frequency change rate is in the range of-3 kHz / s ~ 3 kHz / s.
【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)】：TN911.23
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 段瑞楓;劉榮科;周游;王閏昕;侯毅;;一種低復(fù)雜度的極低信噪比高動(dòng)態(tài)信號(hào)載波粗捕獲算法[J];航空學(xué)報(bào);2013年03期
，本文編號(hào)：2296721
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