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Method of determining a position using satellites

  • US 5,105,198 A
  • Filed: 08/23/1990
  • Issued: 04/14/1992
  • Est. Priority Date: 01/11/1989
  • Status: Expired due to Fees
First Claim
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1. A method of determining the position of an observation point on the earth using M satellites disposed on geosynchronous orbits, comprising the steps of:

  • (a) transmitting a reference signal at a predetermined time from a first one of N satellites of M satellites (N<

    M) disposed on geosynchronous orbits to an observation point and to an adjacent second satellite of the N satellites, the geosynchronous orbits having a predetermined orbit inclination angle with respect to the equitorial plane such that the sequence of N satellites of the M satellites are simultaneously in the range of vision of said observation point;

    (b) causing the second to (N-1)th satellites to relay the reference signal received from each of their respective adjacent preceding satellites to the respective adjacent subsequent third to Nth satellites, said second to Nth satellites sending signals to the observation point when the reference signal is received from the respective adjacent preceding satellite;

    (c) measuring at the observation point the arrival times of the reference signals transmitted from the N satellites;

    (d) calculating the orbit position of the N satellites on the basis of the arrival times obtained in said step (c) and estimated values of the orbit positions of the satellites within the geosynchronous orbits provided by a control station on the earth; and

    (e) determining at least three hyperboloids each having foci on adjacent two of the calculated orbit positions of the N satellites, whereby the position of the observation point is determined at an intersecting point of the hyperboloids.

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