高精度室内可见光定位算法

High accuracy indoor visible light positioning algorithm

针对目前室内定位算法精度不高、实现复杂等问题,提出了一种基于白光LED的可见光室内定位方法。首先利用由室内不同LED发出的定位参考信号到达定位终端的时间差(TDOA)的测量估计,得到定位终端到达两个LED的传输距离之差,以此构造距离估计目标函数,然后采用有约束非线性规划算法得到定位终端的位置坐标,从而有效地解决了室内噪声环境中常规TDOA定位算法不收敛或误差偏大的问题。同时,为了进一步优化定位性能,将距离信息引入加权因子中,提出了质心加权混合定位算法。将提出的定位算法在5 m×5 m×3 m的空间区域中进行了仿真实验,同时考虑噪声因素的影响,结果表明,提出的距离估计目标函数法在信噪比(SNR)为2dB的条件下可以达到平均5cm的定位误差,采用质心加权处理后平均定位误差仅为3cm,有效地提高了室内定位精度和系统应用的普适性及鲁棒性。

Aimed at some limitations of current indoor localization algorithm with low accuracy and com- plex implementation, an indoor visible light positioning method is proposed in this paper by using white lighting LEDs. In this method, the position terminal receives pilot signals transmitted by various LEDs so that the time difference of arrival （TDOA） of these signals can be estimated, thereby the differences of transmission distance between the terminal and LEDs are obtained to construct a distance estimate ob- jective function. By utilizing a nonlinear programming algorithm with constraints, the position coordinates of the terminal can be obtained. It effectively solves the problem of divergence as well as large deviation in the case that conventional TIX）A algorithm is used in indoor noisy environments. Meanwhile, the transmission distance information as a weighted factor is introduced in the positioning called centroid weighted localization algorithm in order to optimize the positioning results further. The performance of the proposed localization method is evaluated in the room measuring 5 mX 5 mX 3 m by simulation with the effect of noise. The simulation results show that the objective function method can achieve a high es- timation accuracy of 5 em in average with SNR= 2 dB,and the average localization error of the eentroid weighted algorithm is only 3 era,which effectively improves the indoor positioning precision and univer- sality of application and system robustness.