Terrain aided underwater navigation using pockmarks

Terrain aided navigation techniques are attractive for obtaining submerged position fixes for an underwater vehicle. However, their use is dependent on a certain degree of variation in the terrain. This paper investigates the performance of terrain navigation algorithms in an area with pockmarks, i.e. craters in the sea bed formed by expulsion of gas or water from the sediments. We use real terrain data from an area with pockmarks, together with simulated vehicle and multibeam echo sounder measurements, to investigate the behavior of the terrain navigation techniques in the area. The simulations indicate that this type of terrain is suitable for terrain aided navigation. The pockmarks also seem to be sufficiently different to provide unique fixes. As pockmarks often occur in flat terrain, traditionally thought of as not suited for terrain navigation, the use of pockmarks facilities terrain navigation in a number of new applications.