LOST2: results from sea trials

Develops and demonstrates an accurate underwater positioning system, LOST2. LOST2 nonlinearly combines parts of dead-reckoning, acoustic-based, and terrain-based positioning into a single integrated system. The LOST2 system is composed of two major subsystems, a system observer and a constrained extended Kalman filter. Inputs to the system are as follows: 1) high resolution bathymetry, 2) measured ocean depth at the position of the vessel, 3) measured or estimated vessel velocity, 4) slant range to and position of a known point, and 5) an initial prediction of the vessel´s location. The system is capable of providing position estimates with the same degree of accuracy as present methods, with significantly less hardware. The system development is briefly discussed, and results from tow body and UUV sea trials are presented. The results of the field trials demonstrate the viability of the system as a new method to position underwater vessels