窄带通信信号源的高精度时差估计

【作者】 王琰；

【导师】 万群；

【作者基本信息】 电子科技大学 ， 信息获取与探测技术， 2008， 硕士

【摘要】 本文研究了在通信、雷达、声纳、遥测等领域中都有着广泛而重要应用的时差(TDOA, time difference of arrival)参数估计问题。文中主要针对窄带信号源这一类特定的辐射源进行时差估计研究。在建立窄带信号时差估计系统模型的基础上,结合窄带信号的特点,对接收机系统模型误差以及窄带信号频域时差估计算法进行了深入的分析。文中推导提出了一些具有理论及实用价值的算法,并通过大量仿真实验验证了算法的性能。归纳起来,本文的主要内容及创新点包括以下几个方面:(1)分析时差参数估计问题的理想系统模型,总结了时域和频域两种基本的基于相关思想的估计方法。在此基础上分析了由接收机不完备性引入的各种系统模型误差,包括有限观测时间长度、采样卡时钟周期误差以及中频接收机频偏,并分析它们对时差估计结果的影响,进而提出对采样周期误差和通道间频偏的校正方法。(2)结合窄带信号时差估计特点,在建立窄带信号源时差估计模型的基础上,分析了应用频域估计方法处理窄带信号模型的优势及具体算法。并利用窄带信号在进行快速傅立叶变换(FFT)过程中,频域有效输出点远小于时域输入点这一特性,提出在算法中引入裁减FFT(FFT Pruning)的思想,实现了频域TDOA估计的快速算法,达到降低运算量的效果。(3)建立简单的室内多径模型,利用已知的多径传播环境信息对互相关函数的多个谱峰进行解模糊,从而确定各条路径之间的时差值。同时通过构造虚拟基站,将多径引入的时差信息用于定位,在该模型假设下可以利用两个接收机对信号源定位。更多还原

【Abstract】 This dissertation focuses on the TDOA (time difference of arrival) estimation problem which has various and important applications in the fields of communication, radar, sonar and so on. Corresponding to time delay estimation of narrowband signals, a lot of research has been done in this paper. In the considered narrowband signals scenario, a practical system model of time delay estimation is derived. In the following, the errors caused by receiver system imperfections and the frequency-domain TDOA estimation method are developed and analyzed in detail. Several theoretically and practically valued algorithms are proposed and derived. Computer simulations and their results are given to verify the efficiency of these algorithms. The main contribution of this dissertation can be concluded as follows:(1) Firstly, ideal system model of TDOA estimation is analyzed, and time/frequency-domain estimation methods are summarized. Then, it is shown how imperfections of the receiver system model will affect the considered correlation-based time delay estimations, and the system errors include the limited acquisition interval, sampling frequency reference error and oscillator frequency error. At last, the adjusting algorithms for system model error are proposed.(2) Based on narrowband signals, a TDOA estimation model is proposed. In the following, the advantages of frequency-domain estimators and estimation algorithm for narrowband signals are analyzed in detail. For narrowband signals, significant time-saving can be achieved in FFT since the number of output samples required to be computed is small. It can be used in frequency-domain estimators and computation can be efficiently reduced.(3) A novel acoustic source localization approach utilizing multi-path information in a reverberant environment is proposed. Making use of environment information, the TDOA of multi-path can be identified. By constructing virtual receivers, the TDOA caused by multi-path can be used for localization, and a closed-form solution to the acoustic source location can be obtained by only two receivers.更多还原