Systems and methods to compensate a frequency

1. In a satellite communications system involving a satellite vehicle SV 1 and a second satellite vehicle SV 2 moving relative to one another, a method for compensating at least one of a transmission frequency associated with SV 1 and a received frequency associated with SV 2 , the method comprising the steps of:

predicting a motion of satellite vehicle SV 1 and generating a first output signal representative of the predicted motion of satellite vehicle SV 1 ;

predicting a motion of satellite vehicle SV 2 and generating a second output signal representative of the predicted motion of satellite vehicle SV 2 ;

supplying said first output signal and said second output signal to a processor and computing in said processor at least one of a compensating transmission frequency and a compensated receiving frequency based on said first output signal and said second output signal;

determining an actual motion of SV 1 and generating a third output signal representative of the actual motion of SV 1 ;

determining an actual motion of SV 2 and generating a fourth output signal representative of the actual motion of SV 2 ;

supplying said first output signal and said third output signal to a first summing junction and generating a first feedback signal representative of the difference between said first output signal and said third output signal;

supplying said second output signal and said fourth output signal to a second summing junction and generating a second feedback signal representative of the difference between said second output signal and said fourth output signal;

using said first feedback signal to improve the accuracy of said first output signal; and

using said second feedback signal to improve the accuracy of said second output signal.

2. A method of compensating a frequency associated with a first communications node or a second communications node in a communications system, comprising:

generating a first signal representing a predicted motion of said first communications node;

generating a second signal representing a predicted motion of said second communications node;

computing at least one of a compensated transmission frequency or a compensated receiving frequency based on a predicted relative motion between said first and second communications nodes, wherein said predicted relative motion is based on said first and second signals;

generating a third signal representing an actual motion of said first communications node;

generating a feedback signal representing a difference between said first signal and said third signal; and

applying said feedback signal to improve accuracy of said first signal.

3. The method of claim 2 , wherein said generating a first signal comprises:

utilizing a static or dynamic flight plan associated with said first communications node to generate said first signal.

4. The method of claim 3 , wherein said static or dynamic flight plan includes information relating to acceleration.

5. The method of claim 3 , wherein said static or dynamic flight plan includes information relating to trajectory.

6. The method of claim 3 , wherein said static or dynamic flight plan includes information relating to speed.

7. The method of claim 3 , wherein said static or dynamic flight plan includes information relating to position.

8. The method of claim 2 , wherein said generating a second signal comprises:

receiving a real - time update including ephemeris data associated with at least one of said first communications node or said second communications node to generate said second signal.

9. A communications system that compensates a frequency associated with a first communications node or a second communications node, comprising:

a motion predictor configured to provide a first signal representing a predicted motion of said communications node;

a data block configured to provide a second signal representing an actual motion of said first communications node;

an element configured to adjust said first signal based on a difference between said first and second signals; and

a processor configured to compute at least one of a compensated transmission frequency or a compensated receiving frequency based on a predicted relative motion between said first and second communications nodes;

wherein said predicted relative motion is based on said first signal and a third signal that is representative of a predicted motion of said second communications node.

10. The communications system of claim 9 , wherein at least one of said first or second communications nodes is stationary.

11. The communications system of claim 9 , wherein at least one of said first or second communications nodes is mobile.

12. The communications system of claim 9 , wherein at least one of said first or second communications nodes is airborne.

13. The communications system of claim 9 , wherein at least one of said first or second communications nodes is space- based.

14. The communications system of claim 9 , wherein said data block is configured to provide real- time updates that include ephemeris data associated with at least one of said first or second communications nodes.

15. A communications node, comprising:

a motion predictor configured to obtain a first signal representing a predicted motion of said node;

a data block configured to obtain a second signal representing an actual motion of said node;

an element configured to adjust said first signal based on a difference between said first and second signals; and

a processor configured to compute at least one of a compensated transmission frequency or a compensated receiving frequency based on a predicted relative motion between said node and a second communications node;

wherein said predicted relative motion is based on said first signal and a third signal that is representative of a predicted motion of said second communications node.

16. A communications system, comprising:

means for predicting a motion of a first communications node to generate a first signal representing the predicted motion of said first communications node;

means for predicting a motion of a second communications node to generate a second signal representing the predicted motion of said second communications node;

a processor to compute at least one of a compensated transmission frequency and a compensated receiving frequency based on said first signal and said second signal;

means for determining an actual motion of said first communications node to generate a third signal representing the actual motion of said first communications node;

means for determining an actual motion of said second communications node to generate a fourth signal representing the actual motion of said second communications node;

means for generating a first feedback signal representing a difference between said first signal and said third signal to improve accuracy of said first signal; and

means for generating a second feedback signal representing a difference between said second signal and said fourth signal to improve accuracy of said second signal.

17. A communications system, comprising:

a first communications node, including

a first motion predictor to generate a first signal representative of a predicted motion of said first communications node,

a first data block to generate a second signal representative of an actual motion of said first communications node, and

a first element that generates a first feedback signal representative of a difference between said first signal and said second signal to improve accuracy of said first signal;

a second communications node, including

a second motion predictor to generate a third signal representative of a predicted motion of said second communications node,

a second data block to generate a fourth signal representative of an actual motion of said second communications node, and

a second element that generates a second feedback signal representative of a difference between said third signal and said fourth signal to improve accuracy of said third signal; and

a processor to compute at least one of a compensated transmission frequency or a compensated receiving frequency based on said first signal and said third signal.

18. The communications system of claim 17 , wherein at least one of said first communications node or said second communications node is a moving satellite.

19. The communications system of claim 17 , wherein at least one of said first communications node or said second communications node is a ground- based station.

20. The communications system of claim 17 , wherein at least one of said first communications node or said second communications node is a space- based vehicle.

21. The communications system of claim 17 , wherein at least one of said first communications node or said second communications node is an airborne vehicle.

22. The communications system of claim 17 , wherein said first communications node or said second communications node includes said processor.