A spring-mass-support structure is arranged as an accelerometer with two electrostatic feedback loops so as to measure two components of acceleration. Two of such accelerometers are advantageously used on a submerged platform to determine the direction of a sound source in a body of water. One of such feedback loops of each accelerometer is used to measure low frequency gravitational acceleration applied to the platform as a result of the tilt of the platform due to the action of current and wave action of the water. The other of the feedback loops of each accelerometer measures sound wave induced acceleration on the platform. The gravitational acceleration of each accelerometer is used to compensate the higher frequency acceleration for the effect of tilt of the platform.
