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

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Inamiya, Kenichi
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US07/571,760
• Time in Patent Office: 600 Days
• Field of Search: 342/457, 342/352, 342/357
• US Class Current: 342/457
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

A method of determining the position of an observation point on the earth using M satellites on geosynchronous orbits having predetermined orbit inclination angle such that N (<M) satellites are in the range of vision of the observation point. One of the N satellites generates a reference signal at a known time. This reference signal is sent directly to the observation point, sequentially relaved to the remaining subsequent satellites and transmitted from the respective satellites in order upon receiving the reference signal from a preceding adjacent satellite to the observation point. The observation point measures the differences in time of reception of the signals from the N satellites. The position of the observation point is determined as an intersecting point of the hyperboloids each having foci on adjacent two of the satellite positions.

Claims

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.

2. A method as set forth in claim 1, wherein said step (e) includes the step of calculating the mutual range between two adjacent satellites of the N satellites.

3. A method set forth in claim wherein number N is at least four.

4. A method of determining the position of an observation point on the earth using five or more satellites disposed on geosynchronous orbits, comprising the steps of:

(a) transmitting a reference signal at a predetermined time from a first one of four satellites of five or more satellites disposed on geosynchronous orbits to an observation point and to a second satellite adjacent to the first satellite, the geosynchronous orbits having an inclination angle of substantially 6 degrees with respect to the equitorial plane such that a sequence of four satellites of the five or more satellites are simultaneously in the range of vision of the observation point and that the anomalies of the four satellites are separated from one another substantially at an angle of 120 degrees at the same point of time

(b) causing in the sequential order the second and third satellites to relay the reference signal to the adjacent third and fourth satellite respectively;

(c) causing the second to fourth satellites each in response to receipt of the reference signal from the adjacent respective first to third satellites to transmit the received reference signal to said observation point;

(d) determining at the observation point the times of reception of the reference signals transmitted from the four satellites;

(e) calculating the positions of the four satellites using the reception times determined in said step (d) and estimated values of the orbit positions of the four satellites within the geosynchronous orbits obtained from a control station on the earth; and

(f) determining three hyperboloids each having foci on adjacent two of the calculated positions of the four satellites, whereby the position of the observation point is determined as an intersectingg point of the hyperboloids.

5. A method as set forth in claim 4, wherein said step (a) includes transmitting the reference signal from the first of the four satellites at a time calibrated by the control station.

6. A method as set forth in claim 5, wherein said transmitting step of said step (a) includes transmitting the reference signal from the first of the four satellites at a time calibrated by the control station at an integral-second time.

7. A method as set forth in claim 6 further including the steps of calculating the mutual range between a satellite and an adjacent subsequent satellite and transmitting the calculated results to the observation point.

8. A method as set forth in claim 5, wherein said step (a) comprises:

calibrating a clock means in the first of four satellites by a signal sent from the control station;

in response to the calibrated clock means, transmitting from the first of four satellites a reference signal to the observation point; and

transmitting from the first four satellites the reference signal to the adjacent subsequent satellite.

9. A method for determining the position of an observation point on the earth using five or more satellites disposed on geosynchronous orbits, comprising the steps of:

(a) transmitting a synthesized signal including a time signal designating a transmission time and a reference signal synchronized with the time signal from a first one of four adjacent satellites disposed on geosynchronous orbits to an observation point and to an adjacent subsequent satellite to the first satellite, the geosynchronous orbits having an inclination angle of 6-10 degrees with respect to the equitorial plane such that four adjacent satellites of the five or more satellites are simultaneously in the range of vision of the observation point and that the anomalies of the four satellites are separated from one another substantially at an angle of 120 degrees at the same point of time;

(b) allowing, in sequential order, the adjacent subsequent satellite and the remaining two satellites to transmit a new synthesized signal including the reference signal and a time signal designating a time at the respective satellite, to the observation point and an adjacent subsequent satellite thereto;

(c) determining at the observation point times of reception of the signals transmitted from the four satellites;

(d) calculating the orbit positions of the four satellites from the reception times determined in said step (c) and estimated values of the orbit position of the four satellites within the geosynchronous orbits obtained from the control station on the earth; and

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

10. A method as set forth in claim 9, wherein said steps (a) and (b) comprise:

calibrating a clock means for producing a timing signal in the first of four satellites by a command signal sent from the control station;

generating a reference signal for range measurement;

producing a synthesized signal including the timing signal and the reference signal; and

transmitting from the first of four satellites th synthesized signal to the observation point and the adjacent subsequent satellite.

11. A method as set forth in claim 10, wherein said calibrating step further includes the step of producing the command signal at the control station.

12. A method as set forth in claim 11, wherein said producing step includes the step of producing the command signal on the basis of the time signal contained in the synthesized signal received by the observation point, the calculated positions of the orbits and predicted values of the orbit positions of the four satellites and the standard time at the control station.

13. A method of determining the position of an observation point on the earth using four satellites disposed on geosynchronous orbits comprising the steps of:

(a) transmitting a synthesized signal including a time signal designating a transmission time and a reference signal synchronized with the time signal, from a first of adjacent three satellites disposed on geosynchronous orbits to an observation point and to an adjacent subsequent satellite, the geosynchronous orbits having the inclination angle of substantially 6 degrees with respect to the equitorial plane, such that a sequence of first, second and third satellites of said four satellites are simultaneously in the range of vision of said observation point and that the anomalies of said three satellites are separated from one another substantially at an angle of 120 degrees at the same point of time;

(b) allowing, in sequential order, an adjacent subsequent satellite to the first satellite and remaining subsequent satellites to each transmit a new synthesized signal including the synthesized signal, and a time signal designating a time at the satellite, to the observation point and an adjacent subsequent satellite, thereto;

(c) repeating said steps (a) and (b) after the lapse of a period sufficient for detecting the orbit positions of the three satellites;

(d) determining at the observation point the times of reception of the synthesized signals transmitted from the three satellites in said steps (a) and (b);

(e) calculating the positions of the three satellites when they perform the operations in said steps (a) and (b), using the times determined in step (d) and estimated values of the orbit positions of the three satellites within the geosynchronous orbits obtained from a control station on the earth; and

(f) determining three hyperboloids each having foci on adjacent two of the positions of the three satellites calculated in said step (e), whereby the position of the observation point is determined as an intersecting point of the hyperboloids.

14. A method as set forth in claim 13, wherein said steps (a) and (b) comprise:

calibrating a clock means for producing a timing signal in the first of adjacent three satellites by a command signal sent from the control station;

generating a reference signal for rang measurement;

producing a synthesized signal of the timing signal and the reference signal; and

transmitting the synthesized signal to the observation point and an adjacent subsequent satellite.

15. A method as set forth in claim 14, wherein said calibrating step further includes a step of producing the command signal at the control station.

16. A method as set forth in claim 15, wherein said producing step includes the step of producing the command signal on the basis of the time signal contained in the synthesized signal received by the observation point, the calculated positions of the orbit and predicted values of the orbit positions of the respective three satellites and the standard time at the control station.