A comparative study of DOA estimation using vector/gradient sensors

In this paper, we conduct a comparative study of DOA (direction of arrival) estimation using vector sensors and gradient sensors. Normally, the DOA of the desired source can be estimated by using a pressure sensor array. If we have the location information of sensors in the array, the DOA can be easily estimated by using some classic algorithms such as MUSIC and MVDR. However, sometimes the location information are unknown to us. In [1] Wong and Zoltowski propose an ESPRIT-based underwater acoustic direction-finding method which use vector hydrophones and do not require any location information. However, due to the difficulty of the availability of such vector sensors, an alternative, gradient sensor, is used to combine the differencing measurements from nominally identical triples of pressure hydrophones for estimating the acoustic gradients. Based on the simulations, the gradient sensors is shown to be a good solution due to its combined merits of vector sensors in performance and pressure sensors in availability.