Abstract: In order to solve the problem that there are obvious errors in the conventional models and the expected positioning cannot be realized, a kind of indoor positioning system is designed. The system adopts the standardized rssi ranging model. The experiment shows that the system can solve the problem of positioning error, the error is reduced by 15%, and the reliable result is obtained.

Key words: trilateral localization, indoor positioning , Zigbee communication, received signal strength indicator (RSSI) ranging model