A Hybrid Distance-measurement/Angle-of-arrival Approach to Localization

Localization has received considerable attention because many wireless sensor network applications require accurate knowledge of the locations of the sensors in the network. The two main localization techniques are distance measurement and angle-of-arrival measurement. The former requires extensive calculations to resolve sign ambiguities in calculated angles, while the latter requires careful calibration to provide high accuracy. In this paper, we describe a hybrid technique, in which low-accuracy estimates of the angle-of-arrival are used to resolve the sign ambiguity in distance measurements. In many practical situations, the ambiguity can be resolved with a high probability of success even with an RMS error as high as 30 degrees in the line-of-bearing estimate, which avoids the need for calibration. Early resolution of this sign ambiguity can be used to develop lower-complexity localization techniques using distance measurement.