基于TDOA测向交叉的脉冲声源定位优化方法研究

Usually it is difficult to determine the position of a signal source of impulse sound from a great distance simply by the hyperbolic cross technology of Time Difference of Arrival (TDOA). We will adopt the acoustic sensor array to implement the direction-finding function with TDOA measurements, and then take several arrays to build a network and compute the triangle bearing location of the sound source. However, the traditional direction-finding method cannot ensure to reach the Cramer-Rao lower bound for the array with a random structure. Sometimes the field rolling terrain would heavily result in a systematic error of TDOA measurements. Moreover, an unfavorable geometry structure built by those array positions would deteriorate the triangle bearing location performance. Thus, there are bottlenecks for the direction-finding cross technology to be realized in positioning an impulse sound source if these scientific problems can not be solved. We will focus on the positioning optimization methods of impulse sound source by the intelligent optimization, geometric dilution of precision, and Cramer-Rao lower bound theory. The research contents of this work are summarized as follows: the error distribution character of biased TDOA measurement; the expectation-maximization direction-finding method of biased TDOA measurements; the triangle bearing location method of virtual rotation array. The research results are expected to noticeably improve the localization precision of sound source from a great distance, and enrich the direction-finding cross theory. They can be applied to some important occasions such as anti-terrorist security and battlefield detection.

.通常远距离脉冲声源难以直接通过到达时间差(TDOA)的双曲线交叉技术定位其坐标，我们提出先采用传声器阵列TDOA测向，再将多阵列组网交叉定位声源。但传统的TDOA测向方法不能保证任意结构阵列测向精度达到Cramer-Rao下界，有时野外起伏地形存在严重的TDOA测量偏差，且不利的阵列位置结构会恶化交叉性能，这些科学问题是阻碍测向交叉技术实用化的瓶颈。本课题拟借助智能优化、几何精度因子和Cramer-Rao下界理论，探索脉冲声源定位优化方法。研究内容包括：TDOA有偏测量的误差分布特征、TDOA有偏测量的期望最大化测向方法、虚拟旋转阵列交叉定位方法。研究结果有望显著提高远距离声源定位精度，丰富测向交叉理论，可用于反恐安全和战场探测等重要场合。

本项目主要研究了基于TDOA的传感器阵列测向问题。首先，针对野外起伏地形可能引起严重的TDOA测量偏差问题，基于野外数据分析了TDOA可能存在的有偏测量，建立了TDOA误差分布的概率模型，据此提出了一种消除TDOA有偏测量的期望最大化测向方法，将未知的偏差量也作为待优化求解的参数，联合优化TDOA偏差量和信号源的波达方向。其次，针对传统的伪线性估计没有考虑波达方向子变量之间存在的非线性约束关系，本项目将此约束条件转化为拉格朗日乘子模型，并提出了一种近似方法求解出该乘子，避免了非线性约束优化求解的高计算复杂性问题。本项目的研究内容一方面有利于基于TDOA测量的波达方向估计技术的发展，使传统测向方法得到突破和创新，另一方面也将较好地促进声波方向发现理论的自身发展和完善，为信号处理、目标定位和传感器网络等相关学科方向提供理论工具和新方法。本项目的研究结果可用于枪声定位、反恐安全和智能化战场探测等国防和国家安全场合。