System and method for estimating a pointing error of a satellite antenna

Patent metadata

Field	Value
Publication number	US-11277200-B2
Application number	US-202016826207-A
Country	US
Kind code	B2
Filing date	Mar 21, 2020
Priority date	Mar 28, 2019
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A system for estimating a pointing error of an antenna (ANT) of a satellite, the satellite includes a payload (CU) comprising a multichannel transmitter or receiver comprising a multichannel antenna (ANT), one analogue processing chain per channel and a set of digital integrated circuits (PN), the system comprising an estimation device (EST), implemented aboard the satellite or in a ground station, for estimating a pointing error of the antenna, the device for estimating a pointing error being configured to: acquire, for at least two channels of the transmitter or of the receiver, at least two test signals, each test signal having been transmitted or received by the antenna along a different direction (θ A , θ B ), for at least one pair of acquired test signals, determine, for each test signal, a relative complex gain between the test signal received or transmitted respectively on two distinct channels, determine a comparative measurement between the two test signals from either the ratio between the two relative complex gains and/or the difference between the phases of the two relative complex gains, determine a pointing error (dθ) of the antenna on the basis of the comparative measurement, of the expected directions of transmission or of reception of the test signals (θ A , θ B ) and of a model of the gain of the antenna for each channel and in a plurality of directions.

First claim

The invention claimed is:

1. A system for estimating a pointing error of an antenna (ANT) of a satellite, the satellite comprising a payload (CU) comprising a multichannel transmitter or receiver comprising a multichannel antenna (ANT), one analogue processing chain per channel and a set of digital integrated circuits (PN), the system comprising an estimation device (EST), implemented aboard the satellite or in a ground station, for estimating a pointing error of the antenna, the device for estimating a pointing error being configured to:
acquire, for at least two channels of the transmitter or of the receiver, at least two test signals, each test signal having been transmitted or received by the antenna along a different direction (θ A , θ B ) from the viewpoint of the satellite,
for at least one pair of acquired test signals, determine, for each test signal, a relative complex gain between the test signal received or transmitted respectively on two distinct channels,
determine a comparative measurement between the two test signals from either the ratio between the two relative complex gains and/or the difference between the phases of the two relative complex gains,
determine a pointing error (dθ) of the antenna on the basis of the comparative measurement, of the expected directions of transmission or of reception of the test signals (θ A , θ B ) and of a model of the gain of the antenna for each channel and in a plurality of directions.

2. The system for estimating a pointing error of an antenna according to claim 1 , wherein each test signal is composed of at least one spectral line.

3. The system for estimating a pointing error of an antenna according to claim 1 , wherein the estimation device (EST) for estimating a pointing error is configured to determine a plurality of estimates of a pointing error on the basis of several pairs of test signals transmitted or received in different directions or several different pairs of distinct channels or several frequencies of test signals.

4. The system for estimating a pointing error of an antenna according to claim 1 , wherein the estimation device (EST) for estimating a pointing error is configured to determine a pointing error of the antenna by:
determining, on the basis of the model of the gain of the antenna, a model of comparative measurement between the two test signals, dependent on a pointing error of the antenna, on the frequency and on the expected directions of transmission or of reception of the test signals (θ A , θ B ),
searching for the value of the pointing error which makes it possible to minimize the difference between the comparative measurement and the comparative measurement model taken at this value.

5. The system for estimating a pointing error of an antenna of a satellite according to claim 1 , wherein the payload (CU) comprises a multichannel receiver and the estimation device (EST) for estimating a pointing error is configured to receive, for at least two reception channels, a digitized temporal sample sequence of at least two test signals, the temporal sample sequence being acquired simultaneously from the various channels in the set of digital integrated circuits (PN).

6. The system for estimating a pointing error of an antenna of a satellite according to claim 5 , furthermore comprising at least two test ground stations (ST 1 , ST 2 ), each test ground station being configured to transmit a test signal towards the satellite.

7. The system for estimating a pointing error of an antenna of a satellite according to claim 5 , wherein each test ground station is configured to transmit the test signals in turn on one and the same frequency or simultaneously on distinct frequencies which are sufficiently close to be affected by the same errors.

8. The system for estimating a pointing error of an antenna of a satellite according to claim 1 , wherein the payload comprises a multichannel transmitter, the estimation device (EST) for estimating a pointing error being implemented in a ground station, each test signal received by a different ground station being transmitted by the antenna along a different direction of transmission (θ A , θ B ) from the viewpoint of the satellite.

9. The system for estimating a pointing error of an antenna of a satellite according to claim 8 , furthermore comprising at least two test ground stations (ST 1 , ST 2 ), each test ground station being configured to:
receive a test signal transmitted by the satellite along a different direction from the viewpoint of the satellite,
separate the test signal received on the ground into several signals corresponding to the respective transmission channels of the satellite,
dispatch, to the device for estimating a pointing error, the respective test signals received for at least two distinct transmission channels.

10. The system for estimating a pointing error of an antenna of a satellite according to claim 8 , wherein the system is configured to apply a procedure for multiple access to the test signals transmitted by the satellite.

11. A method for estimating a pointing error of an antenna of a satellite, the satellite comprising a payload comprising a multichannel transmitter or receiver comprising a multichannel antenna, one analogue processing chain per channel and a set of digital integrated circuits, the method comprising the steps of:
acquiring, for at least two channels of the transmitter or of the receiver, at least two test signals, each test signal having been transmitted or received by the antenna along a different direction (θ A , θ B ) from the viewpoint of the satellite,
for at least one pair of acquired test signals, determining, for each test signal, a relative complex gain between the test signal received or transmitted respectively on two distinct channels,
determining a comparative measurement between the two test signals from either the ratio between the two relative complex gains and/or the difference between the phases of the two relative complex gains,
determining a pointing error (dθ) of the antenna on the basis of the comparative measurement, of the expected directions of transmission or of reception of the test signals and of a model of the gain of the antenna for each channel and in a plurality of directions.

12. The method for estimating a pointing error of an antenna of a satellite according to claim 11 , furthermore comprising a step of correcting the pointing of the antenna (ANT) on the basis of the pointing error (dθ).

Assignees

• Thales Sa

Inventors

• Oster Yann

Classifications

• H01Q3/08

  for varying two co-ordinates of the orientation · CPC title

• H04B7/18519 Primary

  Operations control, administration or maintenance · CPC title

• H01Q1/288

  Satellite antennas · CPC title

• B64G1/66 Primary

  Arrangements or adaptations of apparatus or instruments, not otherwise provided for · CPC title

• H04B7/18515

  Transmission equipment in satellites or space-based relays · CPC title