Enhancing RSSI-based Tracking Accuracy in Wireless Sensor Networks Bracha Hod Based on a joint work with: Gaddi Blumrosen, Dr. Tal Anker, Prof. Danny Dolev and Prof. Boris Rubinsky

Motivation Precise tracking systems in an indoor environment are important in many fields, such as sports and medicine Wireless sensor networks can provide motion and location tracking

RSSI-based Tracking RSSI (Received Signal Strength Indicator) is a measurement of the signal power on a radio link RSSI-based tracking includes two steps Range estimation between pairs of nodes based on RSSI measurements Location estimation using geometric or statistical methods applied on the information from all nodes Simple and cheap, widely used, low-power consumption, and not suffer from any drift

Contribution Existing RSSI-based tracking systems provide a tracking accuracy in the scale of a meter Variations in the wireless medium, reflections, scatterers, multi-paths interference Our RSSI-based tracking system achieves an accuracy in the order of a few centimeters Close-proximity High transmission rate

Setup The mobile node transmits data packets The static sensor nodes receive packets from the mobile node and calculate the RSSI The computer processes the information and estimates the mobile node’s location

Close-proximity

Spatial-Temporal Correlation Interpolation Low-pass filter

Spatial-Temporal Correlation Before post-processing After median filter After low-pass filter

High Transmission Rate

Error Analysis

Summary We proposed a new RSSI-based tracking system that achieves a high accuracy Close-proximity High transmission rate Future work Integration of RSSI measurements with other motion sensors More extensive experiments

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