基于TDOA与GROA的信号源被动定位偏差消除技术

本文针对Ho提出的基于TDOA(Time Difference of Arrival)与GROA(Gain Ratio of Arrival)信号源定位的代数闭式解,提出两种偏差消减方法.首先对其闭式解偏差进行了推导,然后给出BiasRed法与BiasSub法两种偏差消减算法,BiasSub法从Ho给出的解中直接减去期望偏差,BiasRed法通过分析误差表达方程并引入二次约束来提升定位估计精度;分析表明两种方法均可针对远距离信号源,在较小高斯误差情况下有效消减定位偏差,BiasRed法可将偏差降低到最大似然估计算法的水平;计算机仿真分析验证了所提算法的性能.

基于TDOAs与GROAs的多信号源被动定位

为提高感知节点位置模糊条件下多目标被动定位结果精度,提出基于TDOAs与GROAs的混合定位代数闭式解算法,该算法联合估计未知信号源位置与带误差感知节点位置,利用TDOAs与GROAs所包含的相同感知节点位置误差信息提升定位精度,并推导得到基于TDOAs与GROAs多目标混合定位的克拉美罗下界(CRLB),仿真结果表明,所提算法能较好的达到CRLB,并且GROAs信息的引入给多目标定位精度带来明显性能提升.

基于TDOA与GROA的多运动站误差配准算法

针对多运动站无源定位过程中存在系统误差的问题,该文提出一种基于到达时差(TDOA)与到达增益比(GROA)最小二乘配准算法。该算法利用泰勒展开把非线性的量测方程线性化,利用最小二乘算法得到对目标状态和系统误差的联合估计,并考虑了量测噪声和站址误差的影响。同时推导了存在量测噪声、站址误差和系统误差时的克拉美罗下界(CRLB),并分析了系统误差对CRLB的影响。多种条件下的仿真表明,该算法对系统误差和目标状态的估计精度较高,说明了算法的有效性。

基于飞行理论萤火虫算法的TDOA与GROA定位机制

节点定位是无线传感器网络中最为关键的一项技术。针对无源定位的问题,提出一种到达时间差(TDOA)和到达信号增益比(GROA)联合定位算法,并且采用飞行机制的萤火虫算法(GSO)来求得最终结果。结合TDOA和GROA定位模型,引入辅助变量将方程伪线性化;然后采用修正两步加权最小二乘算法(TSWLS)来进行求解。并且在不影响收敛速度和精度的前提下,采用带有飞行机制的GSO算法来寻求目标定位的最优解,克服粒子群算法易陷入局部最优的缺点。仿真结果表明,该算法相比较TDOA算法,定位精度提高了23 d B,并且具有相对较高和较稳定的定位精度。

BFGS quasi-Newton location algorithm using TDOAs and GROAs

With the emergence of location-based applications in various fields, the higher accuracy of positioning is demanded. By utilizing the time differences of arrival （TDOAs） and gain ratios of arrival （GROAs）, an efficient algorithm for estimating the position is proposed, which exploits the Broyden-Fletcher-Goldfarb-Shanno （BFGS） quasi-Newton method to solve nonlinear equations at the source location under the additive measurement error. Although the accuracy of two-step weighted-least-square （WLS） method based on TDOAs and GROAs is very high, this method has a high computational complexity. While the proposed approach can achieve the same accuracy and bias with the lower computational complexity when the signal-to-noise ratio （SNR） is high, especially it can achieve better accuracy and smaller bias at a lower SNR. The proposed algorithm can be applied to the actual environment due to its real-time property and good robust performance. Simulation results show that with a good initial guess to begin with, the proposed estimator converges to the true solution and achieves the Cramer-Rao lower bound （CRLB） accuracy for both near-field and far-field sources.

基于TDOA与GROA的信号源两步加权多维标度定位技术

首先利用时差与增益比测量值求得目标与接收站之间的距离值,再利用基于测距定位的多维标度定位技术(MDS)实现目标定位。仿真结果表明,所提算法在参数测量误差较小时能够达到定位CRLB,且性能优于两步加权最小二乘(TSWLS)算法。

基于TDOAs与GROAs信息的多信号源约束总体最小二乘定位算法

基于辐射源信号的到达时间差(TDOA)和到达增益比(GROA)信息,提出一种协同多信号源进行联合定位的约束总体最小二乘定位算法。首先推导出协同多信号源TDOAs和GROAs信息的伪线性观测模型,并在TDOAs/GROAs测量误差和观测站位置扰动误差同时存在下建立约束总体最小二乘定位优化模型,设计出相应的数值优化算法。仿真实验表明,在观测站位置存在扰动误差下,协同多目标进行联合定位比单个目标分离定位具有更高性能增益,并且约束总体最小二乘定位算法比已有文献中两步加权最小二乘闭式解具有更高的噪声门限。

Semidefinite programming approach for TDOA/GROA based source localization

Time-differences-of-arrival （TDOA） and gain-ratios-of- arrival （GROA） measurements are used to determine the passive source location. Based on the measurement models, the con- strained weighted least squares （CWLS） estimator is presented. Due to the nonconvex nature of the CWLS problem, it is difficult to obtain its globally optimal solution. However, according to the semidefinite relaxation, the CWLS problem can be relaxed as a convex semidefinite programming problem （SDP）, which can be solved by using modern convex optimization algorithms. Moreover, this relaxation can be proved to be tight, i.e., the SDP solves the relaxed CWLS problem, and this hence guarantees the good per- formance of the proposed method. Furthermore, this method is extended to solve the localization problem with sensor position errors. Simulation results corroborate the theoretical results and the good performance of the proposed method.