CELESTIALLY REFERENCED ELECTRONIC SPACE TRACKING

Robert Irving

Peer Reviewed

Abstract:	Increased interest in tracking of and telemetry from long range venicles, and investigation of ever fainter radio stars, has led to increased requirements for accuracy angular positioning of larger steerable antennas. The low-altitude earth-orbiting satellites can be tracked quite precisely using range and range-rate information from pulse-doppler radars having relatively poor angular information. In this case the antenna positioning problem is primarily that of placing the transmitted beam on the target close enough to the beam axis to obtain a useable radar reflection. As shown in Fig.1, this situation begins to break down as the satellite altitude approaches a synchronous orbit, as the angle subtended at the satellite by the baseline between the radars is too smal to permit either radar to sense a sufficient portion of the orbital velocity. For lunar and interplanetary vehicles a similar situation exists, in that range and range-rate information provides only one dimension of the three required to define the trajectory. Even in the case of the low-altitude satellites, improved angular accuracy is required in order to obtain precise orbital information in the shortest possible time, as in the case of certain military applications. These and other potential uses of precise angular tracking and pointing sytems are shown in Fig. 2.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 12, Number 4
Pages:	321 - 329
Cite this article:	Irving, Robert, "CELESTIALLY REFERENCED ELECTRONIC SPACE TRACKING", NAVIGATION: Journal of The Institute of Navigation, Vol. 12, No. 4, Winter 1965-1966, pp. 321-329.
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