直扩信号的参数检测与估计综述

直扩信号自提出以来,其检测和参数估计就一直是电子对抗方所面对的难题。文章概述了现有的估计各参数的方法及其优缺点,并结合国内外的研究现状和现在的需求,对未来的发展作出了展望。     

一种QPSK-DS信号参数估计方法

基于QPSK-DS信号的结构特征,从直扩通信的基本特征和QPSK-DS信号做平方及延迟相乘处理后所具有的典型特征入手,探寻可实现对QPSK-DS信号参数估计的方法。提出了一种基于时域信号处理与频域特征提取的QPSK-DS通信参数估计方法,该方法通过对接收信号做平方和延迟相乘处理然后搜索特征谱线的方法完成对QPSK-DS扩频参数符号周期和码片时宽的估计。仿真试验表明该方法简单有效,可操作性强。     

Optimal Regularization Parameter of the Multichannel Filtered- x Affine Projection Algorithm

We discuss the optimal regularization parameter of the Filtered- Affine Projection (FX-AP) algorithm suitable for feedforward active noise control. While the original FX-AP algorithm always provides a biased estimate of the minimum-mean-square solution, we show that the optimal regularized FX-AP algorithm is capable to eliminate the bias of the asymptotic solution and thus that the regularization parameter can optimize both the convergence speed and the residual MSE of the algorithm. We derive some expressions for the optimal regularization parameter, and we discuss some heuristic estimations of the optimal regularization parameter in practical conditions.     

Bounds on Error in Signal Parameter Estimation

In this correspondence, the problem of lower bounds on mean-square error in parameter estimation is considered. Lower bounds on mean-square error can be used, for instance, to bound the performances, namely the attainable output signal-to-noise ratio, of pulse modulation transmission systems, such as pulse-position modulation (PPM) or pulse-frequency modulation (PFM). The tightest lower bounds to mean-square error previously known are the Ziv-Zakai bounds; the analysis carried out in this paper, which is based on an inequality first obtained by Kotel'nikov, leads to lower bounds tighter than previously known bounds.     

压缩域信号参数估计算法

参数估计作为盲信号处理的关键环节,对后续信号的侦察处理意义重大.提出一种压缩域信号参数估计算法,通过分析不同测量矩阵下稀疏系数的位置特征,对信号参数进行预判;通过引入降升调频思想,提高了参数估计的分辨率;利用多级搜索策略,大大减少了稀疏字典原子个数,降低了运算复杂度.仿真结果和理论分析表明,算法在没有增加运算复杂度的前提下信号参数估计性能明显提高.     

Link16数据链信号参数估计方法研究

Link16数据链信号采用了一种混合扩频通信方式,具有较强的反侦察和抗干扰性能。通过分析该通信信号结构和射频调制技术,提出了信号的载频、码速率和扩频序列等关键参数的估计方法,分别设计了用于估计Link16数据链信号载频、码速率和对信号扩频序列估计的误比特率测试的仿真实验。仿真结果表明,该参数计算法可以为后续的信号检测时的增加样本数量提供理论基础。     

Improved Lower Bounds on Signal Parameter Estimation

An improved technique for bounding the mean-square error of signal parameter estimates is presented. The resulting bounds are independent of the bias and stronger than previously known bounds.     

MF-TDMA信号检测和参数估计系统

MF-TDMA卫星通信系统具有节省卫星资源、组网灵活、网络易扩展等优点,因而得到了越来越广泛的应用.文中主要介绍了在卫星通信中的MF-TDMA信号的识别和参数估计系统,该系统具有循环平稳特性.     

一种短波跳频信号参数估计的方法

针对短波跳频信号跳速慢、一跳持续长、多径效应的特点,采用多窗口叠加,把截获信号分成若干段,分别对其进行重排Gabor谱分析,提取频率脊线,再把脊线按顺序拼成一个整体,从而提取跳频信号的参数。     

低信噪比下LFMCW信号的参数估计

针对线性调频连续波(LFMCW)雷达信号特征参数提取的问题,提出了一种参数估计的方法。首先根据信号自相关函数的特点,进行峰值距离的平均,实现了调制周期的估计。然后通过解线调法得到信号的调频斜率,再通过共轭匹配法进行起始时间的搜索,得到信号的起始频率。与其他方法相比,该算法在减少计算量的同时,具有较强的抗噪性。仿真结果验证了该算法可以在低信噪比(SNR)下对LFMCW进行参数估计,具有很好的参数估计性能。     

基于循环谱的MSK信号参数估计

分析了MSK信号的谱相关特性,在此基础上提出了一种基于循环谱的MSK信号载频和波特率估计算法,通过对算法渐近特性和消失特性的分析,得出了算法随数据采样点的增加以速率收敛的结论.计算机仿真实验证明了该算法在低信噪比下具有较好的性能.     

信号DOA和极化参数的自适应估计

运用ESPRIT算法进行信号参数的估计,关键是对信号子空间的估计。在实际运用中,接收到的信号的参数往往是随时间变化的,因此要得到信号参数的实时估计值就需要根据阵列的接收数据对信号子空间进行更新。分析了如何运用ESPRIT算法得到信号的DOA和极化参数,并在矩阵扰动理论的基础上,利用矩阵特征分解一阶修正方法更新特征值和特征向量,从而使得ESPRIT算法能够自适应地估计信号DOA和极化参数。最后通过Matlab仿真验证了该方法的有效性。     

Signal Parameter Estimation Using 1-Bit Dithered Quantization

Motivated by the estimation of spatio-temporal events with cheap, simple sensors, we consider the problem of estimation of a parameter thetas of a signal s(x;thetas) corrupted by noise assuming that only 1-bit precision dithered quantized samples are available. An estimate that does not require the knowledge of the dither signal and the noise distribution is proposed, and it is analyzed in detail under variety of nonidealities. The consistency and asymptotic normality of the estimate is established for deterministic and random sampling, imprecise knowledge of sampling locations, Gaussian and non-Gaussian noise (with possibly infinite variance), a wide class of dither distributions, and under erroneous transmission of the binary observations via binary-symmetric channels (BSCs). It is also shown that if approximation to the log-likelihood equation in the full precision case yields a good estimate, then there is a corresponding good estimate based on 1-bit dithered samples. The proposed estimate requires no more computation than the maximum-likelihood estimate for the full precision case and suffers only a logarithmic rate loss compared to the full precision case when uniform dithering is used. It is shown that uniform dithering leads to the best rate among a broad class of dither distributions. A condition under which no dithering leads to a better estimate is also given     

基于时频表示的LFM信号参数估计方法

宽带非平稳干扰LFM信号对DSSS系统通信性能威胁较大,为抑制其干扰,必须估算LFM信号参数。在此介绍了几种时频表示方法及其特点,然后采用Radon变换或Hough变换相结合的方法进行LFM信号参数估计,讨论了LFM参数估算过程对时频表示方法的要求。分析表明,选择适当的函数是时频分布估计LFM信号参数的重点,分数傅里叶变换有相对好的LFM信号参数估计性能。     

Parameter Estimation Approach of FSK/PSK Radar Signal

A parameter estimation approach of reconnaissance hybrid radar signal combined frequency-shift keying(FSK) and phase-shift keying(PSK) is presented.Firstly,the multi-phase difference is adopted to calculate the instantaneous frequency(IF) of FSK/PSK,then the frequency points of FSK are estimated from the histogram of IF.The code rate of PSK is extracted from the locations of phase discontinuity.Finally,the multi-phase difference of the square of the received signal is computed to estimate the code rate of FSK.The presented algorithm has higher accuracy of parameter estimation when the signal-to-noise ratio(SNR) is above 11 dB.     

一种新的基于L_p范数的极小化信号参数估计方法

提出了一种新的基于L_P范数的参数估计方法,利用非光滑规划技术时原有方法进行了改进,仿真结果表明新方法具有很强的稳健性和很高的效率。     

基于FRFT的多LFM信号的分离及参数估计

线性调频（LFM）信号在某个阶次的FRFT域中具有能量聚集性,根据这一特性采用分数阶傅里叶变换（FRFT,Fractional Fourier Transform）来分离多个未知任何先验参数的LFM信号,通过在FRFT域搜索峰值点来检测并分离出LFM信号,并用相关系数对分离效果进行了评价。针对二维搜索峰值点的计算复杂性,提出了曲线拟合优化技术来进行FRFT模值检测,把二维搜索转化为一维曲线拟合问题,并介绍了高斯混合模型近似FRFT模值分布。计算机仿真表明,这一方法极大地降低了计算复杂度,对多分量LFM信号进行了有效的分离及参数估计。     

基于FrFT的LFM信号检测与参数估计算法

针对线性调频(Linear Frequency Modem,LFM)信号的快速检测和高精度参数估计问题,在分析LFM信号特征和分数阶傅里叶变换(FrFT)原理的基础上,基于快速解线性调频技术,提出了一种LFM信号检测和参数估计算法,该算法将LFM信号检测由二维搜索转换为一维搜索,从而有效地减少了运算量。仿真结果表明,算法在低信噪比下具有良好的参数估计性能。