PRECISE POSITIONING OF A SHIP AT SEA UTILIZING VLF TRANSMISSIONS

Gregory N. P. A. Rupport, Ralph Bernstein, and Carl O. Bowin

Peer Reviewed

Abstract:	LONG RANGE RELATIVE PRECISE positionin was attempted with the use of existing very low frequency (VLF) radio transmitters, shipboard receivers and precision frequency standards. The VLF receivers were i&ally set to a calculated time delay at a known geographic location. The change in range (determined from the transmission time delays and propagation velocities) combined with known transmitter locations was used to determine an updated ship’s position. A computer algorithm which converts the observed time delays to precise ship’s position was used and is described in this paper. The analytic approach uses the Andoyer-Lambert distance formula for computing propagation distances and azimuth angles relative to the transmitter locations by an iterative method. A shipboard digital computer was used to solve the algorithm which converges on the true ship’s position from an assumeds hip’sp osition, even with large initial position errors. Computer simulation of the navigation system and actual shipboard results are presented.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 16, Number 2
Pages:	110 - 128
Cite this article:	Rupport, Gregory N. P. A., Bernstein, Ralph, Bowin, Carl O., "PRECISE POSITIONING OF A SHIP AT SEA UTILIZING VLF TRANSMISSIONS", NAVIGATION: Journal of The Institute of Navigation, Vol. 16, No. 2, Summer 1969, pp. 110-128.
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