Testing a GPS-based System for the Support of Ship Berthing Operations

Mami Ueno and Rock Santerre

Abstract:	This study was conducted concerning a ship's automatic berthing system where is required precise and real-time estimation of the state vector, i.e., for a 300-m ship, position ±0.3 m, velocity ±0.02 m/s, heading ±0.05° and yaw rate ±0.02°/s. GPS (Global Positioning System) is now fully operational and provides a continuous all-weather service worldwide. Rapid and reliable cycle ambiguity resolution provides the ultimate accuracy for GPS positioning and attitude determination. In the present study, algorithms for a GPS-based system, have been developed, which make synergetic use of all the GPS observations and the characteristics of ship's berthing. Tests were conducted on board the hydrographic sounding ship "F.C.G. Smith", to verify the performance of algorithms and the quality of the navigation solution for an onboard GPS-based system consisting of an optimal 4-antenna configuration (baseline ca. 1.4 m). The ship is a stable catamaran platform, which was considered suitable for simulating a large ship. During the tests, the distance between the ship and the reference station was always less than 1 km. The position of the ship was compared to that provided by an automatic tracking total station. Attitude determination was tested by comparing GPS results with those of the TSS sensor and gyrocompass onboard. The correct solution of ambiguities allowed precise determination of position and attitude and led to the following results: 1) the RMS values (1s) of the difference of horizontal position and height between the total station and GPS were ±6 cm in horizontal position and ±2 cm in height, in moving environment for the distance to the reference station, ca. 1 km and 2) the RMS values of the difference of GPS attitude angles with the outputs of external sensors were: ±0.4° for roll, ±0.3° for pitch and ±0.6° for yaw with 1.4 m of antenna separation. The algorithms developed allow fast ambiguity resolution and would be suitable for real-time applications. Since the precision of attitude can be improved by extending the baselines between the antennas on board the ship (ca. 10 m), the GPS-based system has the potential to be used for a berthing guidance system.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	1271 - 1280
Cite this article:	Ueno, Mami, Santerre, Rock, "Testing a GPS-based System for the Support of Ship Berthing Operations," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 1271-1280.
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