Trajectory Estimation System for an Orbiting Satellite

• US 20080275598A1
• Filed: 05/03/2007
• Published: 11/06/2008
• Est. Priority Date: 05/03/2007
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Schwartz, Lawrence
• Granted Patent: US 7,725,259 B2
• Time in Patent Office: Days
• US Class Current: 701/13
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: B64G 1/26 using jets

Abstract

In one embodiment of the disclosure, a computing system includes a processor and a computer readable medium. The computer readable medium is operable to, when executed on the processor, determine an estimated trajectory of a satellite using a sequential mode of operation, perform a thruster burn, receive a data point from an uplink/downlink facility, determine an estimated trajectory and an estimated thruster performance of the satellite based upon the received data point. If the trajectory error is above a specified threshold level, repeat receiving an updated data point from the uplink/downlink facility, determining an updated estimated trajectory and an updated estimated thruster performance of the satellite based upon the updated data point, and determining an updated trajectory error based upon the updated data point.

Claims

1. A system for calculating an estimated trajectory and an estimated thruster performance of a satellite comprising:

a processor; and

a computer program stored in a computer-readable medium, and executable on the processor, the computer program operable, when executed on the processor to;

determine an estimated trajectory of a satellite using a sequential mode of operation;

perform a thruster burn;

receive a data point from an uplink/downlink facility;

determine an estimated trajectory and an estimated thruster performance of the satellite based upon the received data point using a least squares algorithm;

determine, using the least squares algorithm, a trajectory error of the satellite based upon the received data point, the trajectory error including a vector quantity indicating position error in space and a scalar error value; and

wherein if the trajectory error is above a specified threshold level, the computer program is further operable to repeat at least one time;

receive an updated data point from the uplink/downlink facility;

determine an updated estimated trajectory and an updated estimated thruster performance of the satellite based upon the updated data point;

determine an updated trajectory error of the satellite based upon the updated data point; and

wherein if the trajectory error is below a specified threshold level, determine an estimated trajectory of a satellite using a sequential mode of operation.

2. The system of claim 1, wherein the computer program is further operable to determine the data point using ranging information from the uplink/downlink facility.

3. The system of claim 1, wherein the computer program is further operable to determine the data point using telemetry information from the uplink/downlink facility.

4. A system comprising:

a processor; and

a computer program stored in a computer-readable medium and executable on the processor, the computer program operable, when executed on the processor to;

determine an estimated trajectory of a satellite using a sequential mode of operation;

perform a thruster burn;

receive a data point from an uplink/downlink facility;

determine an estimated trajectory and an estimated thruster performance of the satellite based upon the received data point;

determine a trajectory error of the satellite based upon the received data point;

wherein if the trajectory error is above a specified threshold level, the computer program is further operable to repeat at least one time;

receive an updated data point from the uplink/downlink facility;

determine an updated estimated trajectory and an updated estimated thruster performance of the satellite based upon the updated data point;

determine an updated trajectory error based upon the updated data point.

5. The system of claim 4, wherein the computer program is further operable to determine the estimated trajectory of the satellite using a sequential mode of operation further comprises determining the estimated trajectory of the satellite by calculating a plurality of data points from the uplink/downlink facility over a corresponding plurality of elapsed periods of time.

6. The system of claim 4, wherein the computer program is further operable to determine if the trajectory error is less than a specified threshold level, and if the trajectory error becomes less than the specified threshold level, determine the estimated trajectory of the satellite using the sequential mode of operation.

7. The system of claim 4, wherein the trajectory error includes a vector quantity indicating position error in space and a scalar error value.

8. The system of claim 4, wherein the satellite includes a microwave transponder circuit.

9. The system of claim 4, wherein the computer program is further operable to determine an estimated trajectory and an estimated thruster performance of the satellite using a bounded algorithm.

10. The system of claim 9, wherein the bounded algorithm is a least squares algorithm.

11. The system of claim 4, wherein the data point is referenced to three dimensional Cartesian space.

12. The system of claim 4, wherein the computer program is further operable to determine the data point using ranging information from the uplink/downlink facility.

13. The system of claim 4, wherein the computer program is further operable to determine the data point using telemetry information from the uplink/downlink facility.

14. A method for calculating an estimated trajectory of a satellite following a maneuver comprising:

determining an estimated trajectory of a satellite using a sequential mode of operation;

performing a thruster burn;

receiving a data point from an uplink/downlink facility;

determining an estimated trajectory and an estimated thruster performance of the satellite based upon the received data point;

determining a trajectory error of the satellite based upon the received data point; and

if the trajectory error is above a specified threshold level, repeating at least one time;

receiving an updated data point from the uplink/downlink facility;

determining an updated estimated trajectory and an updated thruster performance, and an updated trajectory error of the satellite based upon the updated data point; and

determining an updated trajectory error of the satellite based upon the updated data point.

15. The method of claim 14, wherein determining a trajectory error further comprises determining a trajectory error including a vector quantity indicating position error in space and a scalar error value.

16. The method of claim 14, further comprising determining, using a least squares algorithm, an trajectory error from the estimated trajectory.

17. The method of claim 14, wherein the satellite includes a microwave transponder circuit.

18. The method of claim 14, further comprising determining the data point using ranging information from the uplink/downlink facility.

19. The method of claim 14, further comprising determining the data point using telemetry information from the uplink/downlink facility.

20. The method of claim 14, wherein determining an estimated trajectory using a sequential mode of operation further comprises determining an estimated trajectory by calculating a plurality of data points from the uplink/downlink facility over a corresponding plurality of elapsed periods of time.

21. The method of claim 14, further comprising if the trajectory error becomes less than the specified threshold level, determining the estimated trajectory of the satellite using the sequential mode of operation.