Radiation pattern correlation for mobile robot localization in low power wireless networks

We present a new method for localization using received signal strength indicator (RSSI) in ordinary wireless communication networks such as specified by IEEE 802.15.4. The method exploits the anisotropy of the antenna gain to determine the bearing of the robot relative to reference radio nodes. This method is not only more precise than the mapping of the RSSI to distance only, it also allows to estimate the orientation of the robot and to monitor the integrity of the measurement. The integrity measure is also incorporated into the RSSI to distance mapping and a thorough error analysis is presented. The paper describes the localization concept and presents experimental results for mobile robot localization in an outdoor environment. The achieved accuracy is significantly increased compared to previously developed RSSI based localization methods.