An Experimental Study of an Integrated GPS/INS System for Shallow-Water AUV Navigation (SANS)

Abstract

The Naval Postgraduate School's "Phoenix" AUV has thus far been operated only in a test pool environment. In preparation for open water testing, currently planned for mid-1996, a series of towfish experiments are being conducted in Monterey Bay to investigate the feasibility of integrated GPS/INS transit mode navigation, in significant sea states, using a GPS antenna mounted only a few inches above the AUV body. In this configuration, either wave action or deliberate submergence will cause loss of GPS position fix information for periods extending from several seconds to a few minutes. The main research question being investigated is, therefore, to determine whether or not a low cost strapped down IMU can be used to navigate accurately between GPS fixes. Our goal is to achieve inertial navigation accuracy comparable to GPS accuracy during periods between successive GPS fixes. Experimental results reported in this paper indicate that this is feasible.