Extended Phase Accordance Method: A Real-time and Accurate Technique for Estimating Position and Velocity of Moving Objects using Ultrasonic Communication

Abstract

The Phase Accordance Method, as previously proposed by the authors, shows a high level of accuracy in localizing static objects. However, its performance degrades when localizing moving objects because of the Doppler effect. In this paper, we propose an extension of the Phase Accordance Method, called the Extended Phase Accordance Method, to cancel the errors in localizing moving objects. Moreover, with this method we can obtain the velocities of objects, along with their positions, by using a combined ultrasound waveform of two different frequency carriers of a known power ratio. The fine point of the proposed method is that it uses virtually the same algorithm as the original position-only method but it can estimate positions and velocities simultaneously and hence achieve real-time tracking of moving objects. Through computer simulations and real-world experiments, we have proved that the proposed method has the same level of accuracy as the Phase Accordance Method. In real-world experiments, the Extended Phase Accordance Method achieved less than 1 mm standard deviation in the 1.0–1.8 m distance measurement of a moving object whose velocity ranged from –1.5 m/s to 1.5 m/s.

Keywords

• Localization
• Tracking
• Velocity estimation
• Doppler effect