【作者】 孙成朋；

【导师】 于铭；

【作者基本信息】 哈尔滨工程大学 ， 信号与信息处理， 2010， 硕士

【摘要】 无源定位能够在隐蔽的状态下连续工作,是重要的侦察手段。针对DS-SS通信信号,本文提出一套无源定位理论方案。方案从估计DS-SS信号到达时间差(TDOA)入手,设计了相关法估计TDOA的快速算法,借助FFT能够把运算量减小到直接进行相关运算的很小一部分。接着就相关法面临的问题,导出频域交织子空间法,着力解决了直接使用常规的子空间法估计TDOA时低输入信噪(干)比、有限带宽和信道频率响应估计的有偏性三个问题。该方法能够识别小于一个码片时延的多径信号,对各路信号的TDOA予以超分辨率的估计,使TDOA测量精度满足战术定位要求。由于使用了无源匹配滤波器进行接收,对干扰也有很好的抑制作用。在介绍TDOA测量技术之后,还探讨了对敌未知码结构DS-SS信号TDOA测量方法,尝试对LPI信号源侦察定位。最后在高精度,超分辨率TDOA测量的基础上进行目标坐标估算,力求达到最小方差定位。条件允许的情况下增加一个主站信号到达角测量值进行定位,由于信号到达角测量技术已经非常成熟,本文不对AOA测量作过多的探讨。综合利用TDOA和仅有的一个AOA测量值,提出了一种近似最优的TDOA-AOA-2LS定位算法,以闭合解的形式给出了目标的最小方差定位结果。与仅用TDOA测量结果的TDOA-2LS方法相比,TDOA-AOA-2LS第二次近似带来的误差完全可以忽略,因而在能够在更大的范围内逼近克拉美-罗界,保持最优估计性能。仿真结果表明,在通信(话音)可以容忍的干扰和噪声环境中,方案可以对100km距离上的目标提供GDOP小于300m的定位,满足作战和训练的需求,为DS-SS信号源战术定位提供了理论依据。更多还原

【Abstract】 Passive location, which can work silently for quite long time, is an important reconnaissance strategy. This paper provides a scenario aiming at location of a DS-SS communication signal emitter. Starting with estimating TDOAs of the DS-SS signals, the scenario projects first a fast correlation method that can reduce the amount of calculation to a small fraction of original amount by means of FFT. However, the cross correlation method suffers a lot from the small delay multi-paths and jamming. Frequency domain subspace method with interleaving can solve these two problems. This algorithm exerts extensive efforts to solve three problems, the low input SNR, limited frequency samples and biased estimation of the channel frequency response in normal subspace TDOA methods, distinguishing multi-path signals with arrival difference less than 1 chip time from each other, acquiring high precision and super resolution TDOAs. Receiving the signals by passive match filter can suppress most jamming. Following the TDOA estimating methods provided is interception of the DS-SS code in noisy and interferential background, in order to utilize the super resolution method to estimate the TDOAs of unknown DS-SS signals. Based on the high precession, super resolution estimate of TDOAs, the target is located with the least square error. An AOA value is added to the TDOAs when it is convenient to get the AOA information in the main base. As the AOA estimation belongs to another task, no more discussion provides here. Colligating the TDOAs and the only one AOA, TDOA-AOA-2LS, a method that can get optimum results is provided. Compared with twice in TDOA-2LS utilizing only the TDOA information, this method approximates only once, so as to keep location errors’rms achieving the Cramer-Rho bound with larger TDOA errors tolerance. The simulation indicates that this scenario satisfies tactic location, supplying theoretic foundation for location of DS-SS signal emitter.更多还原