Azimuth Angle Estimation Using a Dual Accelerometer Vector Sensor with Active and Passive Underwater Signals

During decades, the direction of arrival estimation, in terms of azimuth and elevation angles, have been obtained using the pressure acquired with hydrophones or arrays of hydrophones. More recently, the particle velocity information became important in this research area, since the left/right ambiguity can be canceled when Vector Sensors (VS) or VS Arrays (VSA) are used, due to their high spatial directivity. The main objective of this paper is to estimate azimuth angles using a prototype called Dual Accelerometer Vector Sensor (DAVS) with active and passive underwater signals. The DAVS consists of a pressure sensor and two tri-axial accelerometers arranged in a compact unit. The advantage of this equipment is its portability and autonomy. Therefore, it can be easily deployed or embarked in a moving platform. The experimental data results presented in this paper were obtained during the REX’17 experiment where: 1) the DAVS was mounted in an AUV for azimuth angles estimation using active signals and 2) the DAVS was moored in a fixed position collecting passive signals from sources of opportunity. The azimuth estimation results are stable during time, for both active and passive signals, leading to the conclusion that this compact device may be used for platforms self-localization and in operations involving target detection. Keywords–Azimuth angle estimation; Vector Sensor signal processing; Intensity based method, Pressure and particle velocity combination.