Testing and Evaluation of an Integrated GPS/INS System for Small AUV Navigation

A Small AUV Navigation System (SANS) is being developed at the Naval Postgraduate School. The SANS is an integrated GPS/INS navigation system composed of low-cost and small-size components. It is designed to demonstrate the feasibility of using a low-cost strap-down Inertial Measurement Unit (IMU) to navigate between intermittent GPS fixes. The present hardware consists of a GPS/DGPS receiver, IMU, compass, water speed sensor, water depth sensor, and a data processing computer. The software is based on a twelve-state complementary filter that combines measurement data from all sensors to derive a vehicle position/orientation estimate. This paper describes hardware and software design, and testing results of the SANS. It is shown that results from tilt table testing and bench testing provide an effective means for tuning filter gains. Ground vehicles testing verifies the overall functioning of the SANS, and exhibits an encouraging degree of accuracy. Published in IEEE Jnl. of Oceanic Engineering, v24 n3 p1-21, Jul 1999.