Satellite location and pointing system for use with global positioning system

• US 5,446,465 A
• Filed: 06/29/1993
• Issued: 08/29/1995
• Est. Priority Date: 06/18/1993
• Status: Expired due to Fees

• Current Assignee: Adroit Systems, Inc. (General Dynamics Corporation)
• Original Assignee: Adroit Systems, Inc. (General Dynamics Corporation)
• Inventors: Rodgers, Charles E., Diefes, Debra L., Fan, Leopold C.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/083,267
• Time in Patent Office: 791 Days
• Field of Search: 342/357, 342/359, 342/352, 342/419, 455/12.1
• US Class Current: 342/357.34
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/54 using carrier phase measurements; using long or short baseline interferometry
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured

Abstract

A system for determining location and pointing angle to a selected one of a first series of orbiting satellites as provided, wherein information relating to the system and desired satellite, is provided the electronic signals emitted by a second series of orbiting satellites. System is hand-held, compact, and portable, and is adapted to work in any environment, being immune to magnetic deviations. The satellite locating and pointing system makes use of certain hardware configurations and mathematical algorithms to determine location, and elevation information with respect to both the user and the desired satellite. The mathematical algorithms are also adapted to reduce errors inherent in incoming information from said satellites.

Claims

1. A system for determining the location of and pointing angle to a selected one of a first series of orbiting satellites by receiving telemetry and other electronic signals provided by a second series of orbiting satellites, calculating the location of said system from said telemetry and other electronic signals, and calculating the location and pointing angle of said selected one of said first series of orbiting satellites relative to the location of said system, said system comprising:

antenna array means comprising at least two discrete antenna, said antenna array adapted to receive the telemetry and electronic signals transmitted by the second series of orbiting satellites;

receiver means electronically communicating with each of said discrete antenna and adapted to interpret the telemetry and electronic signals collected by said antenna array means and to generate receiver output signals;

algorithmic means for locating said selected one of said first series of orbiting satellites and calculating the location of and pointing angle to said selected one of said first series of orbiting satellites; and

microprocessor means for receiving said receiver output signals and for processing said receiver output signals with said algorithmic means to determine the location of and pointing angle to said selected one of said first series of orbiting satellites.

2. A system as defined in claim 1, wherein said algorithmic means calculates the azimuth and elevation of said system and the azimuth and the elevation of said selected one of said first series of orbiting satellites.

3. A system as defined in claim 1, further comprising input means for receiving input by a user, said input means electronically transmitting the input information to said microprocessor means to alter the parameters of said algorithmic means, said input means electrically communicating with said microprocessor means.

4. A system as defined in claim 1, further comprising display means for visually displaying information to a user of said system.

5. A system as defined in claim 4, wherein said information displayed by said display means corresponding to the azimuth and elevation of said system and the azimuth and elevation of said selected one of said first series of orbiting satellites.

6. A system as defined in claim 1, further comprising means for establishing the orientation of said system, said orientation establishing means electrically communicating with said microprocessor means, said algorithmic means comparing information received from said receiver means and said orientation establishing means to determine the orientation of said system.

7. A system as defined in claim 6, wherein said orientation establishing means comprises an inclinometer for measuring the elevation angle of said system, said inclinometer electrically communicating with said microprocessor means.

8. A system as defined in claim 1, wherein said antenna array means comprises three antenna arranged in a generally triangular configuration on an antenna platform, each of said antennae forming a baseline with another of said antennae.

9. A system as defined in claim 8, wherein the length of each said baseline being less than the wavelength of the telemetry and electronic signals provided from said second series of orbiting satellites.

10. A system as defined in claim 1, wherein said antenna array means comprises two antennas, defining a baseline extending between said two antennas.

11. A system as defined in claim 1, wherein said antenna array means and a baseplane upon which said antenna array means is mounted form a pointing plane.

12. A system as defined in claim 1, further comprising auditory information means for providing audio information related to system location.

13. A system as defined in claim 1, wherein said microprocessor means further comprises memory means for storing satellite ephemeris data entered into said microprocessor means through said input means.

14. A system as defined in claim 1, further comprising algorithmic comparing means for selecting one or more preferred satellites from among said second series of orbiting satellites to determine the attitude and orientation of said system.

15. A method of determining the location of and pointing angle to one of a first series of earth orbiting satellites, said method comprising the steps of:

providing means adapted to collect and receive telemetry and other electronic signals from one or more satellites of a second series of earth orbiting satellites, said collecting and receiving means comprising at least two antennas, each of said antenna electrically communicating with a receiver;

providing an algorithm embedded in a microprocessor, said algorithm employing carrier phase interferometry to interpret said received telemetry and electronic signals to calculate the location and attitude of said system and then from the system location and attitude information to calculate the location of and pointing angle to the selected one of said first series of earth-orbiting satellites;

relaying information received by each said antenna and each said receiver to said microprocessor for calculation of the location of and pointing angle to the selected one of said first series of earth-orbiting satellites by said algorithm; and

displaying system location information and information relating to said selected earth orbiting satellites.

16. A method as defined in claim 15, further comprising the step of providing a visual and audio display of the current position of the selected satellite.

17. A method as defined in claim 15, including the further step of calculating elevation and attitude information by employing double differenced carrier phase interferometry.

18. A method as in claim 15, including the further step of providing at least three antennas arranged in an equilateral triangle.

19. A method as in claim 15, including the further step of calculating said location and attitude information by first establishing a coarse measurement of elevation and attitude, with accuracy between about +/-30°

, and subsequently establishing a second, fine measurement of attitude and location improving the accuracy of said first determination to within about +/-0.5°

.

20. A method as in claim 16, wherein said visual information is displayed on a touch sensitive liquid crystal display.

21. A method as in claim 15, including the further step of arranging said three antenna in an equilateral triangle, said antenna mounted upon a base plane and forming a pointing plane.

22. A method as in claim 15, including the further step of calculating the location and pointing angle to each satellite within the said series of satellites.

23. A method as in claim 22, wherein said algorithm selects the best available satellite from said second series of satellites, said selection based upon, at least, satellite visibility and signal quality.

24. A method as in claim 15, wherein said algorithm is further adapted to reduce errors inherent in said telemetry.

25. A method as in claim 15, comprising the further step of plotting location and pointing angle to a selected satellite with respect to a position remote from said system.