MEASUREMENTS OF THE PROPAGATION TIME OF LORAN-C SIGNALS

Tadayoshi Hara, Koji Horiai, Katsuhisa Sato, Mitsumi Fujishita, Satoshi Sakai, Kenzaburo Iwadate, Kazuyoshi Asari

Abstract:	LORAN-C signals of Iwo Jima (9970-M) and Hokkaido (9970-X) of the Northwest Pacific chain were received at 21 locations in northern Japan to estimate the accuracy of time comparison by the LORAN-C method. The distance between transmitting sites and receiving sites ranges from 24 km (9970-X to Onbetsu, Hokkaido) to 1777 km (9970-M to Ajigasawa, Aomori). The Navy Navigation Satellite System was used to determine the antenna location to an accuracy of £10 m, which is necessary to estimate the propagation time. The secondary phase is calculated by the Millington-Pressey method using Brunava's approximate formula for secondary phase computation and an effective conductivity map. The phase delay shows a general tendency of +0.65 microseconds per 100 km with respect to a wave moving at vacuum velocity. The range of deviation is 10.5 microseconds. The observed phase shows the additional delay of about 0.35 microseconds per 100 km. With this correction applied, the observed phase deviates usually in the range of +0.5 microseconds. However, sometimes the observed phase shows deviations as much as +1.5 microseconds, which seem to be due to the terrain effect.
Published in:	Proceedings of the 20th Annual Precise Time and Time Interval Systems and Applications Meeting November 29 - 1, 1988 Sheraton Premiere Hotel Vienna, Virginia
Pages:	145 - 150
Cite this article:	Hara, Tadayoshi, Horiai, Koji, Sato, Katsuhisa, Fujishita, Mitsumi, Sakai, Satoshi, Iwadate, Kenzaburo, Asari, Kazuyoshi, "MEASUREMENTS OF THE PROPAGATION TIME OF LORAN-C SIGNALS," Proceedings of the 20th Annual Precise Time and Time Interval Systems and Applications Meeting, Vienna, Virginia, November 1988, pp. 145-150.
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