RESILIENT VIRTUAL GROUND RECEIVERS

• US 20170353228A1
• Filed: 05/12/2017
• Published: 12/07/2017
• Est. Priority Date: 06/03/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: WATSON, Timothy Douglas, BROWN, III, William Alexander
• Granted Patent: US 9,979,462 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0825 with main and with auxiliary or diversity antennas
• CPC Class Codes: H04B 7/0894 using different delays between antennas
• CPC Class Codes: H04B 7/15592 Adapting at the relay station communication parameters for supporting cooperative relaying, i.e. transmission of the same data via direct - and relayed path cooperative diversity H04B7/024
• CPC Class Codes: H04B 7/185 Space-based or airborne stations; Stations for satellite systemsH04B7/204 takes precedence
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04B 7/18519 Operations control, administration or maintenance
• CPC Class Codes: H04W 56/005 compensating for timing error by adjustment in the receiver

Abstract

An apparatus includes a storage device configured to store location information of multiple receivers and auxiliary data associated with a space vehicle. A motion compensation block configured to correct timing of a received signal by a receiver from a space-vehicle transmitter and to generate a motion-compensated signal having corrected timing for motions of the space-vehicle transmitter. The corrected timing is determined based on stored location information of the receiver and the auxiliary data. The frequency correction block is configured to correct a carrier frequency of the motion-compensated signal using information associated with a synch channel of the received signal and to generate a processed signal.

Claims

1. An apparatus comprising:

a storage device configured to store location information of a plurality receivers and auxiliary data associated with a space vehicle;

a motion compensation block configured to correct timing of a received signal by a receiver of the plurality receivers from a space-vehicle transmitter and to generate a motion-compensated signal having corrected timing for motions of the space-vehicle transmitter, the corrected timing being determined based on stored location information of the receiver of the plurality receivers and the auxiliary data; and

a frequency correction block configured to correct a carrier frequency of the motion-compensated signal using information associated with a synch channel of the received signal and to generate a processed signal.

2. The apparatus of claim 1, wherein the apparatus is implemented using hardware and firmware included in each of the plurality of receivers, and wherein the plurality of receivers comprise a plurality of ground receivers.

3. The apparatus of claim 2, wherein each of the plurality of receivers is configured to communicate the processed signal to a combining processor.

4. The apparatus of claim 3, wherein the combining processor comprises a summation processor including a tapped delay-line filter and is configured to:

receive resilient virtual ground (RVG) radio frames associated with processed signals of the plurality of the receivers;

form training vectors using a training sequence of the synch channel of the received signal;

calculate optimal coefficients associated with the tapped delay-line filter; and

configure the tapped delay-line filter to perform summation of the processed signals of the plurality of the receivers using the optimal coefficients.

5. The apparatus of claim 3, wherein the apparatus is part of the combining processor, and wherein the combining processor is configured to communicate with the plurality of receivers over a network, wherein the network includes the Internet.

6. The apparatus of claim 1, wherein the information associated with the synch channel of the received signal comprises a training sequence and training sequence detection information.

7. The apparatus of claim 1, wherein the auxiliary data comprises orbit parameters, synchronization, and training signal characteristics assigned to the space vehicle.

8. The apparatus of claim 1, wherein the motion compensation block is configured to correct timing of the received signal by reversing a time-variable delay and a phase effect due to propagation delay between the space vehicle and the receiver of the plurality of receivers.

9. The apparatus of claim 8, wherein the motion compensation block is configured to reverse the time-variable delay and the phase effect by removing a dilation, a contraction, and Doppler effects to enable coherent combining of signals received from widely-spaced receivers.

10. The apparatus of claim 1, wherein the frequency correction block is configured to correct the carrier frequency of the motion-compensated signal by removing a carrier frequency offset of time-aligned motion compensated data accumulated over a corresponding synch channel repetition period.

11. A method comprising:

storing location information of a plurality receivers and auxiliary data associated with a space vehicle in a storage device;

correcting timing of a signal based on stored location information of the receiver of the plurality receivers and the auxiliary data and generating a motion-compensated signal having corrected timing for motions of a space-vehicle transmitter, wherein the signal is received by a receiver of the plurality receivers; and

correcting a carrier frequency of the motion-compensated signal using information associated with a synch channel of the signal including training sequence and training sequence detection information and generating a processed signal.

12. The method of claim 11, further comprising coherently combing, using a summation processor and a tapped delay-line filter, processed signals of the plurality of the receivers.

13. The method of claim 12, wherein coherently combing comprises:

receiving resilient virtual ground (RVG) radio frames associated with processed signals of the plurality of the receivers;

forming training vectors using a training sequence of the synch channel of the received signal;

calculating optimal coefficients associated with the tapped delay-line filter; and

performing summation of the processed signals of the plurality of the receivers using the tapped delay-line filter and the optimal coefficients.

14. The method of claim 11, wherein the information associated with the synch channel of the received signal comprises a training sequence and training sequence detection information.

15. The method of claim 11, wherein the auxiliary data comprises orbit parameters, synchronization, and training signal characteristics assigned to the space vehicle.

16. The method of claim 11, wherein correcting timing of the received signal comprises reversing a time-variable delay and a phase effect due to propagation delay between the space vehicle and the receiver of the plurality of receivers.

17. The method of claim 16, wherein reversing the time-variable delay and the phase effect comprises removing a dilation, a contraction, and Doppler effects to enable coherent combining of signals received from widely-spaced receivers.

18. The method of claim 11, wherein correcting the carrier frequency of the motion-compensated signal comprises removing a carrier frequency offset of time-aligned motion compensated data accumulated over a corresponding synch channel repetition period.

19. A satellite communication system, comprising:

a satellite transmitter configured to accumulate terrestrial data;

a plurality of receivers, each receiver configured to receive a raw data from the satellite transmitter and organize the raw data, the raw data including the accumulated terrestrial data;

one or more combiner nodes in communication with the plurality of receivers over a network;

a network controller configured to coordinate operation of the satellite transmitter and the the plurality of receivers;

a storage device configured to store location information of the plurality receivers and auxiliary data associated with the satellite transmitter;

a motion compensation unit configured to correct timing of the organized raw data and to generate motion-compensated signal having corrected timing for motions of the satellite transmitter, the corrected timing being determined based on stored location information of the receiver of the plurality receivers and the auxiliary data; and

a frequency correction unit configured to correct a carrier frequency of the motion-compensated signal using information associated with a synch channel of the received signal and to generate a processed signal.

20. The satellite communication system of claim 19, wherein the motion compensation unit is configured to reverse a time-variable delay and a phase effect by removing a dilation, a contraction, and Doppler effects to enable coherent combining of signals received from widely-spaced receivers, and wherein correcting the carrier frequency of the motion-compensated signal comprises removing a carrier frequency offset of time-aligned motion compensated data accumulated over a corresponding synch channel repetition period.