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Exploiting Ultrasonic Reflections for Improving Accuracy of Indoor Location Tracking

The TDoA (Time Difference of Arrivals) based location tracking systems using the RF and ultrasonic signals often give unacceptable errors due to the line-of-sight limitation of the ultrasonic signal. Overcoming this limitation, this paper proposes a novel TDoA based location tracking technique that explicitly exploits the ultrasonic reflection scenarios in the target location estimation. The proposed system can achieve a high location accuracy with errors smaller than 23 cm even when the lines-of-sight of ultrasonic signals are blocked pretty often and hence they are received through reflections.