Performance Improvements Using Constraints in Marine OTF Ambiguity Resolution

S. Weisenburger and M. E. Cannon

Abstract:	By placing two rover receivers onboard a ship and using several constraints, the time to resolve ambiguities on the fly can be decreased while the reliability of the solution is increased. Possible constraints include a height constraint, a heading and pitch constraint computed between the rover pair, a fixed baseline constraint between the rover pair, and an ambiguity constraint in which the sum of the double difference ambiguities must be equal to zero. In order to determine the effectiveness of these constraints, two tests were carried out. The first test was conducted using a small vessel on a reservoir in the Calgary, Alberta area. Distances between the monitor and rover receivers did not exceed 2km. The second test was carried out on the Okanagan Lake in British Columbia. Here, two monitor stations were used, one in Kelowna and the other in Peachland. The separation between the monitor in Kelowna and rover receivers ranged from 2km to 18km, while the separation for the monitor in Peachland ranged from 20km to 40km. Dual frequency receivers were used in the measurement campaigns which allowed for both Ll-only as well as widelane processing. For both cases, the time to resolution when using all constraints was reduced to less than half compared to the unconstrained solution. The effect of each individual constraint is analyzed and shows that the height constraint is the most effective since the vertical component is the weakest from GPS. It is shown that the effect of the constraints decreases as the distance from the monitor increases. Finally, the effect of the constraints on the reliability of the solution was shown to increase from 80% to 95% when using Ll only observations at distances up to 18km.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	585 - 594
Cite this article:	Weisenburger, S., Cannon, M. E., "Performance Improvements Using Constraints in Marine OTF Ambiguity Resolution," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 585-594.
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