GNSS自适应阵列通道不一致性校正技术研究

发布时间：2018-04-05 03:34

  本文选题：空域干扰抑制　切入点：通道不一致性　出处：《电子科技大学》2014年硕士论文

【摘要】：随着全球卫星导航系统(GNSS,Global Navigation Satellite System)处于日益恶劣的电磁干扰环境下,抗干扰型导航接收机起着越发重要的作用。它利用自适应阵列进行空域干扰抑制(DBF)有效地避免干扰,提高信干噪比,从而有利于接收机后端的信号捕获、跟踪、位置解算功能。然而,在实际应用中,DBF抗干扰性能深受阵列通道不一致性问题的影响。因此,为了保证导航接收机抗干扰能力,对于接收机通道不一致性校正方法的研究要求也越来越迫切。论文围绕GNSS导航接收机自适应阵列通道不一致性的问题展开了深入的研究,目的是提出结合导航接收机特性的通道不一致性校正方法。论文主要工作和具体内容如下:1.研究了卫星导航接收机通道不一致性的特性,发现接收机通道的天线部分是通道不一致性的重要组成部分,不容忽视。而常用的通道不一致性校正方法仅仅考虑了射频前端部分的不一致性。因此,必须针对GNSS自适应阵列通道不一致性研究校正方法。2.研究了通道不一致性对卫星导航接收机的影响。首先从不同的抗干扰性能衡量标准的角度出发,研究发现通道不一致性会造成抗干扰性能恶化,表现为阵列方向图零点深度减小,干扰抑制度减小以及捕获过程中最高峰与次峰比值减小。然后研究发现通道的非理想频率特性会造成卫星信号伪随机码的码元高度、码相位延迟发生变化,进而造成相关峰峰值变化、相关峰出现总体上延迟以及发生倾斜,给码延迟估计带来误差,而通道不一致性则会导致经过不同通道的卫星信号变化不一致。最后通过理论推导发现卫星信号经过各通道后的不一致性变化会造成空域干扰抑制模块输出的卫星信号与本地参考信号的相关峰发生畸变,并且畸变情况随DBF权向量变化,造成码延迟估计误差随加权系数变化,不易补偿,最终导致伪距测量误差。3.研究接收机通道不一致性的窄带模型,提出了一种用于GNSS自适应阵列的通道不一致性窄带校正方法。该方法充分利用导航接收机能够提供位置信息的优势,并且结合导航信号自相关特性以及正交投影原理,在不依赖于任何辅助源的情况下实现了通道不一致性的校正。首先对该方法进行了理论分析,然后通过仿真证明了该方法可以准确估计出表征通道不一致性的误差矩阵的参数,利用该方法校正后的自适应阵列进行DBF时,抗干扰性能得到大大地提升。同时分析了校正过程中的接收信号信噪比SNR以及相关时间T这两个因素对方法性能的影响。最后研究了方法的容差性,分析了卫星信号来波方向这一先验信息的误差来源,通过仿真证明在该先验信息存在最大角度误差时,该方法仍能够很好地实现通道不一致性校正。4.研究接收机通道不一致性宽带模型,提出了一种用于卫星导航接收机的通道频域均衡方法。该方法的关键点是在通道频域均衡前,利用接收卫星信号与本地参考信号的相关峰值及其附近足够多的点,结合在频域上对通道特性进行泰勒级数展开的方式,采用最小二乘求解出泰勒级数系数实现了通道频率特性的在线估计。它有效地避免了常用通道均衡方法中采用线性调频信号(LFM)作为辅助校正信号的诸多缺点。在获取各通道频率响应后,采用逆傅里叶变换频域均衡算法实现了通道不一致性校正。首先对在线估计算法进行了深入的理论分析和仿真验证,证明它能准确估计出通道频率特性,同时分析了算法性能受泰勒级数展开阶数N以及在相关峰值附近取值方式的影响。然后仿真验证了经过逆傅里叶变换频域均衡后的各通道能够达到一致性。最后分析了进行通道均衡后卫星信号码延迟估计误差的来源以及误差补偿方案。
[Abstract]:With the development of global navigation satellite system (GNSS, Global Navigation Satellite System) in the electromagnetic interference environment deteriorating, anti-jamming navigation receiver plays an increasingly important role. It uses adaptive array spatial interference suppression (DBF) can effectively avoid interference, improve the SINR, which is conducive to the acquisition of signal receiver, tracking, position calculation function. However, in the practical application effect of DBF anti jamming performance by array channel inconsistency. Therefore, in order to ensure the ability of anti-jamming navigation receiver, receiver for channel mismatch correction method research also more and more urgent. The GNSS navigation receiver channel adaptive array the consistency problem is studied deeply, the purpose is proposed combining the characteristics of navigation receiver channel mismatch correction method. The main work and The specific contents are as follows: 1. research on the channel of satellite navigation receiver inconsistency characteristics, found that part of the receiver channel channel antenna is an important part of inconsistent, can not be ignored. But the common channel mismatch correction method only considers the inconsistency of the RF front-end. Therefore, according to the GNSS adaptive array Channel Study on the inconsistent impact of channel difference on satellite navigation receiver.2. correction research. First, from the anti-jamming performance of different measure angle, the study found that inconsistency of channels will cause deterioration of the anti-jamming performance, performance for the array nulls depth decreases, the peak time and peak interference suppression ratio in the system of reducing and capture process. Then the study found that non ideal channel frequency will cause the height of the satellite signal symbol of pseudo random code, the code phase. Late changes, causing the correlation peak changes of correlation peaks on the whole delay and tilt to the code delay estimation error, and channel mismatch will lead to change after the satellite signals from different channels are not consistent. Finally through the theoretical derivation that correlation peak satellite signal after the inconsistency of the passage. The change will cause the spatial interference suppression module output of the satellite signal and local reference signal distortion, and distortion with DBF weight vector changes caused by the code delay estimation error changes with the weighted coefficient to compensate, resulting in the pseudorange measurement error of.3. receiver channel inconsistent narrowband model, a method is presented for GNSS adaptive array channel mismatch correction method for narrowband. The method makes full use of the navigation receiver can provide location information advantage, and combined with the air guide The number of self correlation and orthogonal projection principle, does not depend on any auxiliary source is realized under the condition of channel mismatch correction. Firstly, the theoretical analysis of the method, and then the simulation proved that the method can accurately estimate the characterization of channel mismatch error matrix parameters, using the adaptive array the correction method of DBF, anti jamming performance is greatly improved. At the same time analyzed the correction process receiving signal to noise ratio of these two factors SNR and T on time method performance. Finally the tolerance method, analyzed the error sources of satellite signals to the prior information of wave direction the simulation results show that the maximum angle error exists in the prior information, the method can well realize the channel mismatch correction.4. receiver channel inconsistency broadband model, A method for channel frequency domain equalization method for satellite navigation receiver is proposed. The key point of this method is in the channel frequency domain equalization, using the correlation peak to receive the satellite signal and the local reference signal and its near enough points, combined with the Taylor series expansion of channel characteristics in the frequency domain, using the least squares solution of Taylor coefficient the series achieves online channel frequency estimation. It can effectively avoid the LFM signal used in channel equalization method (LFM) as many disadvantages. In the auxiliary correction signal to obtain the channel frequency response, the realization of channel inconsistency correction inverse Fourier transform frequency domain equalization algorithm. Firstly, online estimation algorithm the theoretical analysis and Simulation of verification, show that it can accurately estimate the frequency characteristics of the channel, and the performance of the algorithm was analyzed by Taylor The number of expansion order N and impact on the correlation peak value near the way. Then the simulation verified through inverse Fourier transform frequency domain equalization after each channel can achieve consistency. Finally analyzes the channel equalization after the satellite channel number delay estimation error sources and error compensation scheme.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1

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