基于CPPM-RSSI算法的可见光室内定位技术研究

Research on visible light indoor localization technology based on CPPM-RSSI algorithm

针对如何提高室内定位精度问题,提出一种基于混沌脉冲位置调制(CPPM)和接收信号强度指示(RSSI)相结合的定位算法。利用二值混沌码作为扩频码,对LED灯的位置信息进行扩频处理,然后进行脉冲位置调制(PPM),将调制后的信号发送出去,接收端用相同的二值混沌码解扩恢复出每个LED的位置信息,通过光电检测器(PD)检测到来自各个灯的光强,再结合RSSI算法进行定位。仿真结果表明:在5 m×5 m×2 m的定位空间内,不扩频的情况下,最大误差为51 cm,最小误差为3 cm,平均误差为15.47 cm。随着扩频码长度增加,与之对应的误码率会降低,定位精度也随之提高,当扩频码长度为64位时,最大误差为10 cm,最小误差接近1 cm,平均误差为4 cm。

Aiming at the problem of improving indoor localization precision,a localization algorithm based on chaotic pulse position modulation(CPPM)and received signal strength indication(RSSI)is proposed.Using binary chaotic code as spread spectrum code,spread spectrum processing is carried out to the LED lamp position information,then carries on the pulse position modulation(PPM),sends out the modulated signal,the receiver uses the same binary chaotic code to decode and spread to restore the position information of each LED,through the photoelectric detector(PD)to detect the light intensity from each lamp,then combines with RSSI algorithm for localization.The simulation results show that the maximum error is 51 cm,the minimum error is 3 cm and the average error is 15.47 cm in the 5 m×5 m×2 m positioning space without spread spectrum.As the length of the spread spectrum code increases,the bit error rate will decrease,and the positioning precision will also increase.When the length of the spread spectrum code is 64 bits,the maximum error is 10 cm,the minimum error is nearly 1 cm,and the average error is 4 cm.