CHEN Jun-mei1，YE Juan1，SUN Dao-zong2

（1. Guangzhou College，Guangdong Institute of Science and Technology，Guangzhou 510640，China；

2. College of Engineering，South China Agricultural University，Guangzhou 510642，China）

Abstract：Aiming at locating large device that moves indoors，the theory of indoor positioning and its application were studied and the indoor positioning system based on radio frequency（RF）module was designed. Microcontroller STM32F103 was used as core chip in system hardware to constitute 3 fixed nodes respectively in combination with 3 nanoPAN5375 modules. Mobile node consisted of microcontroller STM32F103 and one small vehicle with nanoPAN5375. Trilateration & centroid algorithm and Kalman filter algorithm

were employed to achieve real-time location. The results indicate that mobile node can move to the given coordinate automatically at 10 cm/s；and more accurate location of mobile node can be obtained after the length of side of equilateral triangle consisting of fixed nodes are increased. The system is proved to be practical and its design scheme can be applied to places where indoor positioning is required， such as indoor workshop，mine，tunnel and protected agriculture.

Key words：indoor positioning；wireless sensor network；nanoPAN5375 module；trilateral centroid algorithm