Position and velocity recovery from independent ultrasonic beacons

In this paper we present a study on how to estimate the position of a mobile receiver using ultrasonic beacons fixed in the environment. Unlike traditional approaches, the ultrasonic beacons are independent, and positioning is performed by measuring the Doppler shift within their observed periods. We show that this approach allows us to deduce both position and velocity, but an analysis of the space indicates that we can recover the direction of velocity very well, the magnitude of velocity less well, and that location estimation is the least accurate. Based on the characteristics of the solution space, we suggest a method for improving positioning accuracy.