R. E. Anderson, R. L. Frey and J. R. Lewis

Peer Reviewed

Abstract: Position Surveillance can be added to a satellite-aided mobile communication service by connecting an automatic responder circuit between the vehicle receiver and transmitter and adding a receiver for signals from another satellite. The technique was tested with a towboat on the Mississippi River using NASA’s ATS-6 satellite and the GOES satellite of the National Oceanic and Atmospheric Administration. A commercial mobile radio base station was adapted for communication through the ATS-6 satellite. The 10-meter antenna on the satellite enabled clear, reliable voice communications with a vehicle transmitter power of 25 watts and a nondirectional, fixed antenna 70 cm tall and 2 cm in diameter. An experimental tone-code ranging transponder was connected between the receiver and transmitter. A 468 MHz receiver for the passive reception of the 100 bit per second timing and data signal of the NOAA-GOES satellite was connected to the responder unit. Tone-code interrogations addressed to the towboat were transmitted from the General Electric Earth Station Laboratory and repeated by the ATS-6 satellite. Each time the towboat received an interrogation, it automatically transmitted its tone-code response followed by a data message stating the time interval between its last received once-per-second time signal from GOES and its reception of the tone-code interrogation. One second after the Earth Station Laboratory transmitted the interrogation, its computer printed out the latitude and longitude of the towboat. Lines-of-position derived from the active ranging through ATS-6 were accurate to about 0.1 nautical mile. The active ranging bandwidth was 2.44 kHz, the integration time was 0.1 second. Lines-of-position derived from the NOAA-GOES signals were accurate to about 1.6 miles. The limitation on accuracy was the 100 Hz bandwidth of the signals. If the bandwidth and signal-to-noise ratio of the GOES signals received on the towboat were approximately the same as the ATS-6 signals, the accuracy of the GOES derived lines-of-position, and the position fixes would have been accurate to about 0.1 nautical miles.
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 27, Number 4
Pages: 305 - 317
Cite this article: Anderson, R. E., Frey, R. L., Lewis, J. R., "POSITION SURVEILLANCE USING ONE ACTIVE RANGING SATELLITE AND TIME-OF-ARRIVAL OF A SIGNAL FROM AN INDEPENDENT SATELLITE", NAVIGATION, Journal of The Institute of Navigation, Vol. 27, No. 4, Winter 1980-1981, pp. 305-317.
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