基于朗伯模型参数估计的VLC室内定位优化算法

为实现高精度室内定位,本文设计了一种可见光 通信(VLC)室内定位系统,并通过 结合优化的朗伯模型、码分多址技术(CDMA)、三边定位算法而有效提升了定位精度和系统 扩展性。首先,每个发光二极管(LED)的ID信息经过直接序列调制后加载到LED驱动电路上 ,LED发出带有自身ID信息的灯光信号。在接收端通过光电探测器(PD)接收灯光信号,并 根据扩频码的正交性恢复出ID信息及接收信号强度(RSS),以此提高信道容量并增强系统 抗干扰能力。然后,根据朗伯光源模型,由三边定位算法得出待定位点的定位估计坐标。为 进一步提高精度,引入k最近邻(KNN)思想,采集适当的指纹点并由指纹点信息对每盏灯在 定位估计坐标处的朗伯光源模型参数进行估计,由优化后的朗伯模型计算出精度更高的定位 坐标。在1m×1m×1.35 m的空间区域中,进行本VLC室内定位系统 的实验测试。结果表明,提 出的高精度VLC室内定位系统的平均定位误差降低至2cm左右,其定位精度相比于传统三边 定 位算法提升了30%。此外,该系统方案所采用基于指纹点信息优化朗 伯模型参数的方法具备良好的实用扩展性,可实现广阔的应用场景。

VLC indoor positioning optimization algorithm based on the parameters estimation of lambertian model

In order to achieve high accurate indoor positioning,this paper desig ns a visible light communication (VLC) based indoor positioning system.By combi ning the optimized Lambertian model,code division multiple access (CDMA) techno logy and trilateral positioning algorithm,the positioning accuracy and system s calability are effectively improved.To begin with,the ID information of each l ight emitting diode (LED) with the direct spread spectrum modulation is loaded t o the LED driver,and the ID bearing LED light signal is launched.At the receiv er,the optical signal is detected by the photodetector (PD) and the ID informat ion with the corresponding received signal strength (RSS) are recovered based on the orthogonality of the spread spectrum code that increases the channel capaci ty and enhances the anti-interference ability of the system.Then,using the Lam bertian model,the location estimation coordinates of the point to be located ar e calculated by the traditional trilateral positioning algorithm.To further improve the positioning accuracy,an optimal approach based on the k-nearest neighb or (KNN) is introduced.The RSS fingerprints of some appropriate points are coll ected and the Lambertian model parameters of each LED are renewed by these finge rprints.Thus,the optimized Lambertian model can be applied to obtain the highe r accurate positioning coordinates.The experimental investigation of the design ed VLC indoor positioning system was carried out in a space region of 1m×1m×1.35m.The results show that the average positioning error of the proposed high ac curate VLC indoor positioning system is reduced to around 2cm,and the positioni ng accuracy is improved by 30% as compared to the traditional trilateral positio ning algorithm.The proposed scheme based the Lambertian model optimization usin g RSS fingerprints has excellent scalability and can be applied in broad applica tions.