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JP-7855582-B2 - System and method for calibrating ground stations

JP7855582B2JP 7855582 B2JP7855582 B2JP 7855582B2JP-7855582-B2

Inventors

  • ブラット，ロイ

Assignees

  • ヴィアサット，インコーポレイテッド

Dates

Publication Date
20260508
Application Date
20211015
Priority Date
20201016

Claims (20)

  1. A system (100) for tracking satellites, Antennas (301, 401) configured to receive a first signal of a first frequency, Tracking feeds (360, 460) and Tracking receivers (350, 450), A first input (330, 430) coupled to the antenna to receive the first signal via the first path, A second input (345, 445) coupled to the tracking feed to receive the first signal via a second path, Calibration outputs (340, 440) for outputting a calibration signal at a second frequency, which are coupled to the first path via a first coupler (310, 410) and to the second path via a second coupler (365, 465), A tracking receiver (350, 450) includes the first inputs (330, 430), the second inputs (345, 445), and calibration components (453, 353) coupled to the calibration output, wherein the calibration components (453, 353) are To store the first receiver calibration coefficient set, The first phase value of the second frequency is determined based at least in part on the calibration signal of the second frequency received at the first input (330, 430) and the second input (345, 445), Determining a second phase value associated with the first frequency from the first phase value, at least in part on a first phase offset between the first frequency and the second frequency, wherein the first phase offset is determined at least in part on a first receiver calibration coefficient set. A system (100) is configured to generate a phase correction value for the received first frequency signal, at least in part, based on the second phase value.
  2. The tracking receiver (350, 450) further comprises at least a first receiver (351, 451) for the first signal of the first frequency and a second receiver (352, 452) for the calibration signal of the second frequency, The system (100) according to claim 1, wherein the calibration components (353, 453) are further configured to determine the second phase value associated with the first frequency based at least in part on a second phase offset between the first receiver (351, 451) for the first frequency and the second receiver (352, 452) for the first frequency, the second phase offset is determined at least in part on a set of first receiver calibration coefficients.
  3. The system (100) according to claim 2, wherein the calibration components (353, 453) are configured to determine the second phase offset from the first receiver calibration coefficient set , at least in part, on gradient, offset, and temperature.
  4. The calibration components (353, 453) are The system (100) according to any one of claims 1 to 3, further configured to select the second frequency for the calibration output, at least in part on the fact that the second frequency is different from the first frequency.
  5. The calibration components (353, 453) are Identifying periodic time intervals for performing calibration, The system (100) according to any one of claims 1 to 4, further configured to generate updated phase correction values for the first signal received through the antenna at the first frequency according to the periodic time intervals.
  6. The system (100) according to any one of claims 1 to 5, comprising a set of antennas (302-a, 302-b, 302-c, 302-d) offset from the antenna (301) configured to receive the first signal of the first frequency, and coupled to the second input (345) via the second path.
  7. The system (100) according to any one of claims 1 to 5, wherein the tracking feed (460) comprises a tracking coupler (403) coupled to the antenna (401), and a first path for receiving the first signal of the first frequency, and the tracking coupler (403) is coupled to the second input (445) via the second path.
  8. The first receiver calibration coefficient set is associated with the first path, The second receiver calibration coefficient set is associated with the third path. The system (100) according to any one of claims 1 to 7, wherein the third input of the tracking receiver is coupled to the antenna (301, 401) to receive the first signal via the third path.
  9. The first set of receiver calibration coefficients is associated with a first polarization type for the signal received by the tracking receiver via the first path, The system (100) according to any one of claim 8, wherein a second set of receiver calibration coefficients is associated with a second polarization type for the signal received by the tracking receiver via the second path.
  10. A first amplifier component (320, 420) is located on the first path and is coupled to the first input of the antenna (301, 401) and the tracking receiver (350, 450), The system (100) according to any one of claims 1 to 9, further comprising: a second amplifier component (325, 425) located on the second path and coupled to the calibration output (340, 440) and the second input (345, 445).
  11. The first amplifier component (320, 420) includes a first low-noise block-down converter. The system according to claim 10, wherein the second amplifier component (325, 425) includes a second low-noise block down converter.
  12. The calibration components (353, 453) are From the calibration outputs (340, 440), calibration signals for each frequency in the frequency set are output. The calibration signal output from the calibration output (340, 440) is received at the first input (330, 430) via the first coupler (310, 410), and then received at the second input (345, 445) via the second coupler (365, 465) . Determining a first phase value set associated with the first receiver (351, 451) of the tracking receiver (350, 450), wherein the first receiver (351, 451) is coupled to both the first input (330, 430) and the second input (345, 445). Determining a second set of phase values associated with the second receiver (352, 452) of the tracking receiver (350, 450), wherein the second receiver (352, 452) is coupled to both the first input (330, 430) and the second input (345, 445). The system (100) according to any one of claims 1 to 11, further configured to generate the first receiver calibration coefficient set based at least in part on the first phase value set and the second phase value set.
  13. The calibration component is, Determining a first slope and a first offset for a first line that fits the difference between the first phase value set and the second phase value set as a function of frequency, The system is further configured to determine a second slope and a second offset for a second line that fits the first set of phase values as a function of frequency, The system (100) according to claim 12, wherein the receiver calibration coefficient set includes at least the first gradient, the first offset, the second gradient, and the second offset.
  14. A method for use in a satellite communication system (100), The first input (330, 430) of the tracking receiver (350, 450) receives a first signal of a first frequency and a calibration signal of a second frequency via a first path. The second input (345, 445) of the tracking receiver (350, 450) receives the first signal of the first frequency and the calibration signal of the second frequency via the second path. The calibration signal is output to the first coupler (310, 410) connected to the first path and the second coupler (365, 465) connected to the second path. Determining a first phase value for the second frequency based at least in part on the calibration signal of the second frequency received at the first input (330, 430) and the second input (345, 445), Determining a second phase value associated with the first frequency from the first phase value, at least in part on a first phase offset between the first frequency and the second frequency, wherein the first phase offset is determined at least in part on a first set of receiver calibration coefficients. A method comprising generating a phase-corrected value of the received first frequency signal based at least in part on the second phase value.
  15. The tracking receiver (350, 450) comprises at least a first receiver (351, 451) for the first signal of the first frequency and a second receiver (352, 452) for the calibration signal of the second frequency, The method according to claim 14, wherein the second phase value associated with the first frequency is determined at least in part on a second phase offset between the first receiver (351, 451) for the first frequency and the second receiver (352, 452) for the first frequency, and the second phase offset is determined at least in part on a set of first receiver calibration coefficients.
  16. The method according to claim 15, further comprising determining the second phase offset from the first set of receiver calibration coefficients based at least in part on gradient, offset, and temperature.
  17. The method according to any one of claims 14 to 16, further comprising selecting the second frequency for a calibration output (340, 440) on at least in part that the second frequency is different from the first frequency.
  18. Identifying periodic time intervals for performing calibration, The method according to claim 14, further comprising generating updated phase correction values for the first signal of the first frequency received according to the periodic time interval.
  19. The method according to claim 14, wherein the tracking feed (360, 460) is associated with an antenna (301) and configured to receive the first signal of the first frequency, and comprises a set of antennas (302-a, 302-b, 302-c, 302-d) offset from the antenna (301), and coupled to the second input via the second path.
  20. The method according to claim 19, wherein the tracking feed comprises a tracking coupler (350, 450) coupled to the antenna (401), and the first path for receiving the first signal of the first frequency, the tracking coupler (350, 450) being coupled to the second input (345, 445) via the second path.

Description

Cross-reference This patent application claims the interests of U.S. Provisional Patent Application No. 63/092,884, filed on 16 October 2020, entitled "SYSTEMS AND METHODS FOR CALIBRATING GEO GROUND STATIONS," which has been assigned to the applicant of this document and is expressly incorporated herein by reference in its entirety. The following generally pertains to communications, including systems and methods for calibrating ground stations (e.g., geosynchronous equatorial orbit (GEO) ground stations). Ground stations may communicate with satellites according to specific communication frequencies (e.g., radio frequency (RF) carrier frequencies). Ground stations may perform frequency tracking for downlink and uplink communications with satellites. Some satellite tracking systems may use labor-intensive phase matching processes across multiple RF paths. RF cables in RF paths may be trimmed for length, and manual phase shifters may be adjusted in the field. Furthermore, amplifiers used in RF paths may be adapted to a reference. Temperature changes may alter the phase of amplifiers, and the phase shift introduced by amplifiers may also shift over time. In addition, long and expensive RF cables may be extended alongside antennas for providing tracking signals. Cables may be damaged in the field. Therefore, tracking techniques at communication frequencies may be used to eliminate the requirements of phase-matched components, manual phase shifters/adjustments, or labor-intensive RF cable trimming. However, while such techniques may need to be performed periodically, they require the temporary suspension or interruption of communications on the communication frequency in order to carry out tracking. The techniques described relate to improved methods, systems, devices, and apparatus for supporting satellite operation. A ground station (e.g., a geosynchronous equatorial orbit (GEO) ground station) may implement a tracking system including a tracking receiver. The tracking receiver may simultaneously receive both a first signal at a first frequency and a calibration signal at a second frequency, as well as a calibration signal at a second frequency, via a first and a second path. The first signal may be a communication signal received via the ground station's antenna. The calibration signal is output by the tracking receiver and is coupled with the first and second paths. Based on the calibration signal, the tracking receiver may determine a first phase value for the second frequency. Then, from the first phase value, the tracking receiver may determine a second phase value associated with the first frequency based on a first phase offset between the first and second frequencies, based on a receiver calibration coefficient set, and then generate a phase-corrected value for the received signal at the first frequency. Phase differences may also exist due to different path lengths between a first receiver of a tracking receiver configured to receive communication signals and a second receiver of the tracking receiver configured to receive calibration signals. During calibration, the tracking receiver may calibrate these differences based on phase offsets identified by a set of receiver calibration coefficients. By performing calibration at a second frequency different from the frequency used for communication signals, the tracking receiver can perform calibration for tracking without interrupting the communication signals, thereby providing more accurate tracking error signals and improving overall system tracking. In some embodiments, having accurate phases enables the tracking receiver to accurately report tracking errors to the antenna controller, thus enabling improved tracking performance. During the characterization phase of the tracking system, for example, during or immediately after the installation or deployment of a ground station, the tracking receiver may generate a set of receiver calibration coefficients using different frequency sets. The tracking receiver may output calibration signals across each frequency in the frequency set and determine the phase of each frequency. The tracking receiver performs calibration on each receiver of the tracking receiver, for example, to account for differences between receivers of the tracking receiver. Values representing different calibration coefficients in the receiver calibration coefficient set may be represented and stored in the tracking receiver. Characterization of the tracking system may allow for the determination of the phase of the communication signal using calibration signals at different frequencies. Figure 1 shows an example of a satellite communications system that supports a system and method for calibrating a ground station according to the embodiments described herein.Figure 2 shows another example of a satellite communications system supporting a system and method for calibrating a ground station according to the embodiments described herein.F