Research on GPS/INS/WIFI Personnel Tight Combination Positioning Method

Abstract

With the development of current information technology, it has become a common demand to obtain accurate location information quickly. However, in the indoor environment where people generally live, GPS signals are partially occluded, and the INS of inertial navigation system will significantly increase the error due to the integral accumulation error. In view of the problems of poor robustness and low accuracy of the existing loose combination positioning methods, a GPS/INS/WIFI personnel tight combination positioning method was proposed by using the WIFI network signals with wide coverage at present. Firstly, the characteristics of WIFI positioning technology were analyzed, and the INS positioning error model was established. The measurement equation under tight coupling was established by using the pseudo range value of GPS and the RSSI parameters of WIFI system, and the state equation was established by using the INS error model, so as to realize the establishment of the combined GPS/INS/WIFI positioning state space equation. Then, based on unscented Kalman filter theory, a GPS/INS/WIFI based compact combined position solution model is established. Finally, the human wearable combined positioning experiment platform was used for experimental verification. The experimental results show that the GPS/INS/WIFI based tight combined positioning method can significantly adapt to the indoor environment with complex interference, has high positioning stability and positioning accuracy, and the maximum positioning error is 0.45m. Compared with the extended Kalman filter and Kalman filter, the positioning accuracy of unscented Kalman filter is improved by 56% and 89% respectively, which can meet the requirements of field use.