Distance Estimation Based on RSSI Improvements of Orientation Aware Nodes

Received signal strength indicator (RSSI) is widely used as an indicator that could be used for distance estimation between two nodes. However, many factors influence on the accuracy of RSSI ranging (e.g. antenna radiation pattern, reflections, obstacles etc.). Hence, RSSI alone is rarely used as a tool for precise distance measurement. In this paper, an improvement of RSSI ranging based on finding the best node orientation is presented. The experimental results are obtained using IRIS wireless sensor network nodes for outdoor and indoor scenarios. It is shown that lower bounds for the relative distance estimation accuracy, using curve fitting for the best orientation outdoor and indoor scenario, are 91% and 57%, respectively.