Real-time navigation on Naval Oceanographic Office survey ships and hydrographic survey launches

The present-day need for accurate survey data in a quick-turnaround environment requires that nearly flawless navigation information be available to a variety of survey sensors. This presents a challenge to system integrators to obtain the best possible measurement of ship´s position, velocity, time, roll, pitch, heading, and vertical displacement with a minimum amount of equipment. In addition, complex corrections are required to compensate for the offsets in physical locations of the various navigation and survey sensors mounted on the vessel and to match the data sampling requirements of each component. The Naval Oceanographic Office survey ships, hydrographic survey launches, and field parties use an integrated navigation system, designed to take advantage of the unprecedented accuracies and reliability available from the Global Positioning System and state-of-the-art strap-down inertial navigation systems, to collect hydrographic and oceanographic data. This paper describes the approach taken in developing this integrated system, the equipment and processes involved, and the potential sources of error. Detailed results of the testing are also presented to evaluate the performance of the system