Research On Indoor Location Of LED Based On CPPM-RSSI Algorithm

As we all know,LED lights have both lighting and communication functions,which lay a good foundation for LED lights to carry out visible light communication.The emerging visible light positioning technology is rapidly emerging,and subsequently has successfully attracted the high attention of scholars at home and abroad,and gradually become a hot spot for research.At present,the requirements for indoor positioning are getting higher and higher.Among the mature indoor positioning technologies,the general positioning accuracy is high,but the cost required for it is also relatively high and easily interfered by the outside world.Visible light communication is an emerging indoor positioning technology with low equipment price,high safety performance and high positioning accuracy,so it has become a new idea for indoor positioning technology.For the problem of improving the accuracy of indoor positioning,this paper proposes a CPPM-RSSI positioning algorithm,which combines Chaos-Pulse Position Modulation(CPPM)and Received Signal Strength Indication(RSSI),the The algorithm uses the binary chaos code as a spreading code,and uses the advantages of chaos such as orthogonality to improve the antiinterference ability of the signal,and then performs the PPM modulation to further improve the anti-interference ability of the signal,sends out the modulated signal,and the receiver side demodulates the received signal with PPM,and uses the same binary chaos code to decompose and recover the position of each LED information,and the light intensity from each lamp is detected by a photoelectric detector,and then combined with RSSI algorithm for positioning,thus realizing indoor positioning.This thesis also investigates the effect of m-RSSI positioning algorithm on visible light indoor positioning accuracy by combining m-sequence in pseudo-random sequence with RSSI algorithm.m-r SSI positioning algorithm is similar to CPPM-RSSI positioning algorithm in principle,and the effect of both algorithms on positioning error is studied under the premise of changing only the spreading sequence.The simulation environment in this thesisis a typical indoor scene,the size of the room is5m×5m×2m,the system includes a photodetector and three light-emitting diodes,the three LEDs are distributed in fixed positions on the roof,and the photodetector is located in the middle of the ground.In this simulation environment,the effects of the two algorithms on the positioning accuracy and the effects of the spreading code length on the positioning accuracy are studied.The simulation results show that as the spreading code length increases,the average positioning error of the CPPM-RSSI positioning algorithm and the m-RSSI positioning algorithm is smaller,and the CPPM-RSSI positioning algorithm has a smaller average positioning error than the m-RSSI positioning algorithm when the spreading code is lower than64 bits.