A Study On Multi-channel Beacon Identification In Ultrasonic Indoor Positioning

Ultrasound indoor positioning has become a hot topic of indoor positioning, due to the comprehensive advantages of accuracy, cost, and sensitivity etc. Ultrasonic multi-beacon identification is to improve the positioning system and anti-jamming capability to achieve precise positioning of key technologies. Beacon identification accuracy directly affects the targeting efficiency. Firstly, there is an ultrasonic level summary of the indoor positioning involved in the basic principles and key technologies. Then expand for multiple ultrasonic beacon identification technology exploration and research, learn communication technologies, research and analysis of the signal following method can correctly identify the beacon.Firstly, introducing the new transducer use polyvinylidene fluoride as piezoelectric material. Studying Frequency Division Multiple Access (FDMA) multiplexing technique based on the beacon identification which is according to the broadband transducer characteristics, combined with frequency division multiplexing principle Transmitting node modulated wideband carrier drive transducers by different frequencies of the beacon encoded. The receiving node separate the effective signal from aliasing signal through a specific frequency, demodulate to restore the original encoded information, and identify the transmission beacon signal to distinguish between different sources.Secondly, for the existing ultrasonic spreading code recognition hardware architecture complicated computational cost and other issues, researched simplified spreading codes multiplexed beacon identification technology. Demodulated and then shaped signal so that microcontroller make autocorrelation operation directly bit by bit from the digital signal, Not only reduces hardware complexity and cost, but also greatly reduces the amount of calculation, and the use of low-end microcontroller can be done.Finally, combining the strengths of frequency division multiple access spread and spectrum coding method, using spread spectrum modulation mode to make ultrasonic carry information presented multiple beacon identification method based on the information spread spectrum modulation. Simulation results show that this approach can completely recover transmit information.by solving a receiving node spread demodulation process In addition, for the advantages of information carried, proposed a method of ultrasonic autonomous positioning without RF, it helps to improve the efficiency of positioning.