Eccentric conformance, satellite-position determination module

• US 6,233,507 B1
• Filed: 01/28/1999
• Issued: 05/15/2001
• Est. Priority Date: 01/28/1998
• Status: Expired due to Fees

• Current Assignee: Douglas H. May
• Original Assignee: Douglas H. May
• Inventors: May, Douglas H.
• Primary Examiner(s): Zanelli, Michael J.
• Assistant Examiner(s): Gibson, Eric M
• Application Number:
  US09/238,830
• Time in Patent Office: 838 Days
• Field of Search: 701/3, 701/13, 701/226, 701/207, 701/208, 701/222, 244/158.R, 244/164, 244/171, 342/357.15
• US Class Current: 701/13
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: B64G 1/244 Spacecraft control systems
• CPC Class Codes: B64G 1/36 using sensors, e.g. sun-sensors, horizon sensors
• CPC Class Codes: B64G 3/00 Observing or tracking cosmonautic vehicles

Abstract

The invention incorporates an eccentric conformance module that determines time and position for a satellite. The eccentric conformance module eliminates the necessity of computing an eccentric anomaly for non-circular orbits by relying on a comparison of a circular orbit and application of a general power equation. The eccentric conformance module produces coordinates in a reference frame relating to an eccentric conformance model. The invention resolves these coordinates through transformation to a common reference frame by computing the transformation between the conformance displacement angle and the true anomaly. Calculations derived from the eccentric conformance module are applicable for ground-based and space-based systems. Applications include determination of line-of-sight pointing for antennas and predictions of satellite positions for intercept or rendezvous transfers and for safe orbit trajectories. All such computations are simplified with the use of the eccentric conformance method.

Claims

1. An apparatus for tracking a satellite, the apparatus comprising:

a processor programmed to execute modules for processing orbit data corresponding to a first position of a first satellite to determine spatial coordinates therefor, the processor further programmed to execute an orbital transformation module;

a memory device operably connected to the processor for storing executable and operational data structures, the data structures comprising;

an eccentric conformance module, executable by the processor to apply conformance rules to produce first satellite coordinates as a function of time;

an orbital transformation module, executable by the processor to transform the satellite coordinates into common reference coordinates; and

a parameter module containing the orbit data relating a first satellite position to a parent body position.

2. The apparatus of claim 1, further comprising an antenna control system operably connected to the processor to direct the position of an antenna to thereby control movement of the antenna in accordance with the common reference coordinates.

3. The apparatus of claim 1, further comprising an attitude control system operably connected to the processor to control a first satellite attitude.

4. The apparatus of claim 1, further comprising:

an input device operably connected to the processor for receiving orbit data;

an output device operably connected to the processor for providing common reference coordinates; and

a telemetry system operably connected to the input and output devices for communicating the inputs to the processor and the outputs from the processor.

5. The apparatus of claim 1, wherein the processor is further programmed to determine a type of orbit path corresponding to the orbit data.

6. The apparatus of claim 1, wherein the orbit data indicates a common reference and the processor is further programmed to execute an orbital transformation module to transform the orbit data into conformance data and to provide the conformance data to the eccentric conformance module.

7. The apparatus of claim 1, wherein the processor is further programmed to execute the eccentric conformance module to determine second coordinates corresponding to a second position of a second satellite.

8. The apparatus of claim 7, wherein the processor is further programmed to provide an intercept trajectory from the first coordinates and second coordinates.

9. A method for tracking a position of a satellite, the method comprising:

receiving first orbit data corresponding to a first satellite;

providing the first orbit data to an eccentric conformance module, executable to apply conformance rules for producing first coordinates corresponding to a first position of a first satellite at a first time;

providing the first coordinates to an orbital transformation module, executable to transform the first coordinates to common reference coordinates reflecting the first position of a first satellite.

10. The method of claim 9 further comprising determining an orbital path corresponding to a first satellite and reflecting the first orbit data.

11. The method of claim 9 further comprising providing the first orbit data to the orbital transformation module to generate conformance data therefrom, the conformance data being processable by the eccentric conformance module.

12. The method of claim 9, further comprising providing second orbit data corresponding to a second satellite to determine second coordinates indicative of a second position corresponding to a second satellite at a second time.

13. The method of claim 12, further comprising determining an intercept trajectory corresponding to the first and second coordinates.

14. The method of claim 9, further comprising directing the position of an antenna in accordance with the common reference coordinates to enable transmission between the antenna and a first satellite.

15. A computer readable medium storing data structures for determining the position of a satellite orbiting a parent body, the data structures comprising:

an eccentric conformance module effective to apply conformance rules to first orbit data reflecting a first satellite position to a parent body position to produce first coordinates; and

an orbital transformation module effective to transform the first coordinates to common reference coordinates.

16. The computer readable medium of claim 15 further comprising a parameter module containing the first orbit data indicative of a first satellite position to a parent body position.

17. The computer readable medium of claim 15, wherein the eccentric conformance module is effective to provide an orbital path of a first satellite based on the first orbit data.

18. The computer readable medium of claim 15, wherein the parameter orbital transformation module is effective to transform the first orbit data to conformance data and to provide the conformance data to the eccentric conformance module.

19. The computer readable medium of claim 15, wherein the eccentric conformance module is effective to process second orbit data indicative of a second position of a second satellite to provide second coordinates.

20. The computer readable medium of claim 19, further comprising an intercept module effective to determine an intercept trajectory of the first and second satellites from the first and second coordinates of the first and second satellites.