The μPAP is a portable system designed for tracking ROV’s, tow fish, divers and other subsea objects. μPAP is a small and compact acoustic positioning system designed for operation from a surface vessel to track ROV’s, tow fish, divers and any other subsea object at several thousand metres range. The system operates in SSBL mode where it measures the distance and direction to subsea transponders and computes a 3D position in local coordinates or in geographical coordinates.