LOCATION OF ATS-5 BY L-BAND TRILATERATION

A. F. Brisken

Peer Reviewed

Abstract:	Near Real-Time ATS-5 satellite positions and short term position predictions were derived from an experimental L-band trilateration network developed by the General Electric Company under contract to NASA. Satellite position accuracies of approximately 0.0002 degrees in latitude and longitude and 20 meters in earth center distance were demonstrated. Individual slant range measurements from the master ground station to the satellite were precise to within 12 meters; from the satellite to each of two automatic remote transponders, 23 meters. The trilateration network comprised a master ground station near Schenectady, New York and remote unmanned transponders in Buenos Aires, Argentina and near Wahiawa, Hawaii. Tone-code ranging signals consisting of a short 9.8 kHz tone burst followed by the unique digital identification code of the addressed transponder frequency modulated a 1651 MHz carrier within a total RF bandwidth of 60 kHz. After a precisely defined internal time delay, only the transponder that recognized its own unique address code retransmitted a tone-code-data response. Self calibration circuits in the transponders returned a measurement of the transponder internal time delay after everv interrogation, eliminating time delay variations as a major source of slant range measurement error.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 23, Number 2
Pages:	106 - 118
Cite this article:	Brisken, A. F., "LOCATION OF ATS-5 BY L-BAND TRILATERATION", NAVIGATION: Journal of The Institute of Navigation, Vol. 23, No. 2, Summer 1976, pp. 106-118.
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