Target motion analysis by inverse triangulation

We propose a new method to estimate the trajectory of a source based on the two angles of the arrival lines of two waves emitted by the source but propagating with two different speeds. This difference between speeds is due to either the different natures of the waves or the different natures of the media in which the waves propagate. The source is assumed to move with a constant velocity and the observer is motionless. First we prove that such a trajectory is observable, and then we propose the maximum likelihood estimate (under Gaussian hypothesis) which is shown to be almost efficient.