Positioning method utilizing artificial satellites in geosynchronous altitude orbits

• US 5,160,935 A
• Filed: 11/27/1991
• Issued: 11/03/1992
• Est. Priority Date: 11/28/1990
• 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): Barron, Jr., Gilberto
• Application Number:
  US07/799,443
• Time in Patent Office: 342 Days
• Field of Search: 342/357
• US Class Current: 342/357.31
• CPC Class Codes: G01S 19/00 Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236

Abstract

A method of positioning an observation point utilizing artificial satellites. In order to make it possible to make a range measurement in areas within the latitude of 65 degrees where almost all people in the world reside, a predetermined first number of satellites, for example, ten satellites are placed in geosynchronous orbits, the inclination angle thereof being set to about six degrees. The respective satellites are placed so that the mean anomalies thereof are equally separated. A control station, which keeps track of a predetermined second number of satellites, monitors signals indicating times and frequencies generated from the satellites and compares the times and frequencies with national standard time and frequency obtained in a ground station, thereby enabling the position of the observation point to be determined. The control station frequently transmits commands for compensating clocks mounted in the satellites whereby each satellite generates a highly accurate signal for range measurement.

Claims

1. A positioning method utilizing artificial satellites for determining the position of an observing point, the method comprising the steps of:

disposing M satellites on geosynchronous altitude orbits having an inclination angle of about six degrees such that the means anomalies of neighbouring two satellites are separated from each other by about 120 degrees at the same time and that N (<

M) satellites are simultaneously visible from said observation point;

transmitting a range measuring signal, having a constant phase for an integral number of seconds based on a time signal calibrated by a control station, from a first one of said N satellites to said observation point and to a subsequent second satellite;

reflecting the received range measuring signal from said second satellite to said first satellite;

transmitting from said first satellite to said control station, the range measuring signal originally generated by said first satellite and the range measuring signal reflected by said second satellite;

comparing the phase of the two range measuring signals in said control station to detect a phase difference therebetween;

transmitting the phase difference from said control station to said second satellite;

transmitting a phase comparison indicator and a range measuring signal, from said second satellite to said observation point, unique to said second satellite and also transmitting the range measuring signal unique to said second satellite from said second satellite to a neighbouring third satellite, thereby transmitting respective range measuring signals and phase comparison indicators from said N satellites to said observation point; and

in said observation point, calculating, for each pair of neighbouring two satellites selected from said N satellites, a difference between the ranges between said neighbouring two satellites and said observation point on the basis of the times of arrival of the range measuring signals, the times of transmision thereof obtained from the range measuring signals and predicted positions of said N satellites, thereby determining the position of said observation point.

2. A positioning method according to claim 1, wherein a hyperboloid drawn by putting said neighbouring two satellites on the focal points is assumed for said each pair of neighbouring two satellites and the position of said observation point is determined as an intersecting point of those hyperboloids.

3. A positioning method utilizing artificial satellites to determine the position of an observing point, the method comprising the steps of:

disposing M satellites on geosynchronous altitude orbits having an inclination angle of about six degrees such that the mean anomalies of neighbouring two satellites are separated from each other by about 120 degrees at the same time, and such that N (<

M) satellites are simultaneously in the visibility of said observation point;

transmitting a range measuring signal, having a constant phase for an integral number of seconds based on a time signal calibrated by a control station, from a first one of said N satellites to said observation point and a subsequent second satellite;

reflecting the received range measuring signal from said second satellite to said first satellite;

comparing the phase of the range measuring signal with the phase of the reflected range measuring signal in said first satellite to detect a phase difference therebetween;

transmitting the phase difference via said control station to said second satellite;

transmitting, from said second satellite to said observation point, a phase comparison indicator and a range measuring signal unique to said second satellite, and also transmitting the range measuring signal unique to said second satellite to a neighbouring third satellite, and transmitting respective range measuring signals and phase comparison indicator from others of said N satellites to said observation point; and

in said observation point, calculating, for each pair of neighbouring two satellites selected from said N satellites, a difference between the ranges between said observation point and respective N satellites on the basis of the times of arrival of the range measuring signals, the times of transmission thereof obtained from the range measuring signals and predicted orbital positions of said N satellites, thereby determining the position of said observation point.

4. A positioning method according to claim 3, wherein a hyperboloid drawn by putting said neighbouring two satellites on the focal points is assumed for said each pair of neighbouring two satellites and the position of said observation point is determined as an intersecting point of those hyperboloids.

5. A positioning method utilizing artificial satellites to determine the position of an observation point, the method comprising the steps of:

disposing M satellites in geosynchronous altitude orbits having an inclination angle of about six degree such that the mean anomalies of neighbouring two satellites are separated from each other by about 120 degrees at the same time, and such that N (<

M) satellites are simultaneously in the visibility of said observation point;

transmitting a range measuring signal, having a constant phase for an integral number of seconds based on a time signal calibrated by a control station, from a first one of said N satellites to said observation point and to a subsequent second satellite;

in said second satellite, dividing the range measuring signal received from said first satellite into three subsignals and reflecting a first one of the subsignals to said first satellite;

in said first satellite, transmitting, to said control station the range measuring signal originally generated by said first satellite and the first one of the subsignals reflected by said second satellite, or a signal indicating the difference in the ranges between said first and second satellites as detected in said first satellite;

in said control station, detecting or receiving the ranges between said satellites, obtaining a time difference between said first and second satellites and transmitting, to said second satellite, signals indicative of the ranges and the time difference between said first and second satellites;

in said second satellite, transmitting a second one of said subsignals as well as the signal sent from said control station to said observation point, and also transmitting a third one of said subsignals to a subsequent third satellite, and transmitting respective range measuring signals and phase comparison information between said satellites to said observation point; and

in said observation point, calculating differences betwen the ranges between said observation point and said satellites for each pair of neighbouring two satellites in the basis of the times of arrival of the range measuring signals, the times of transmission thereof obtained from the range measuring signals and predicted orbital positions of said N satellites, thereby determining the position of said observation point.

6. A positioning method according to claim 5, wherein a hyperboloid drawn by putting said neighbouring two satellites on the focal points is assumed for said each pair of neighbouring two satellites and the position of said observation point is determined as an intersecting point of those hyperboloids.

7. A positioning method utilizing artificial satellites to determine the position of an observation point, the method comprising the steps of:

disposing M satellites on geosynchronous orbits having an inclination angle of about six degrees such that the mean anomalies of neighbouring two satellites are separated from each other by about 120 degree at the same time and that N (<

M) satellites are simultaneously in the visibility of said observation point;

transmitting a range measuring signal, having a constant phase for an integral number of seconds based on a time signal calibrated by a control station, from a first one of said N satellites to said observation point and a subsequent second satellite;

comparing, in said second satellite, the phase of the range measuring signal received from said first satellite with the phase of range measuring signal of said second satellite;

transmitting from said second satellite, said phase comparison information and the range measuring signal sent from said first satellite to said observation point and also transmitting the range measuring signal sent from said second satellite to a subsequent third satellite, and transmitting respective range measuring signals and phase comparison information from others of said N satellites to said observation point; and

in said observation point, calculating, for each pair of neighbouring two satellites selected from said N satellites, a difference between the ranges between said observation point and said neighbouring two satellites on the basis of the times of arrival of the range measuring signals, the times of transmission thereof obtained from the range measuring signals and predicted orbital positions of said N satellites, thereby determining the position of said observation point.

8. A positioning method according to claim 7, wherein a hyperboloid drawn by putting said neighbouring two satellites on the focal points is assumed for said each pair of neighbouring two satellites and the position of said observation point is determined as an intersecting point of those hyperboloids.