GPS based attitude determining system for marine navigation

Under contract with the US Coast Guard, Adroit Systems, Inc. has developed a low cost, GPS based attitude determining system (ADS) for marine navigation, TRIADS. The Coast Guard will use the system for general navigation, as well as hydrographic surveying, ice breaker navigation, and positioning buoys or other objects. Following a successful system demonstration validating the concept design, a system has been developed and tested. The ADS navigation system makes use of the full visible satellite constellation. This allows the GPS based attitude determining system to be designated as a primary navigation sensor. Approval for GPS ADS as a primary navigation system can be pursued now that the constellation is complete. The full constellation also allows the optimum satellite constellation to be selected based on the attitude of a platform. Having more than the required number of satellites available not only enhances system accuracy and robustness, but it also enables the system to perform integrity checks in the form of receiver autonomous integrity monitoring (RAIM)