Loran-C TD Calibration in the Lower St. Lawrence Area Using a Mobile DGPS System

G. Lachapelle, B. Townsend, D. Chen, D. Hains

Abstract:	A mobile, DGPS-based Loran-C calibration system, namely LORCAL2 (LOR CALibration at The University of CALgary), was used to collect some 3,500 km of road and ship data to calibrate the Loran- C Time Differences (TDs) in the Lower St.Lawrence area. These measurements were made in Winter and Summer 91 on the East Coast Canada Chain (593OM, X, Y, Z) and the Northeast US Chain (9960M, W, XI along continuous road profiles between Quebec City and Havre-St-Pierre on the North Shore, Quebec City and the Gaspesia Peninsula on the South Shore, and selected profiles in the river. The seasonal effect on the TDs observed between Winter and Summer reached 0.2 ps. The measured combined effect of the secondary and additional secondary phase lags reached several ps. This measured effect is compared with that predicted using various ground conductivity assumptions to determine the advantages of en-route Loran-C calibration versus the use of phase velocity models. The accuracy gain, in terms of TDs, ranges from 0.5p to a few ps. This translates into a position accuracy gain of several hundred metres in the St.Lawrence area.
Published in:	Proceedings of the 1993 National Technical Meeting of The Institute of Navigation January 20 - 22, 1993 Parc 55 Hotel San Francisco, CA
Pages:	553 - 560
Cite this article:	Lachapelle, G., Townsend, B., Chen, D., Hains, D., "Loran-C TD Calibration in the Lower St. Lawrence Area Using a Mobile DGPS System," Proceedings of the 1993 National Technical Meeting of The Institute of Navigation, San Francisco, CA, January 1993, pp. 553-560.
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