Device and method for positioning a star tracker on a structure

Patent metadata

Field	Value
Publication number	US-9835711-B2
Application number	US-201514874635-A
Country	US
Kind code	B2
Filing date	Oct 5, 2015
Priority date	Oct 3, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A device for positioning a functional trihedron of a star tracker in a reference trihedron tied to a structure on which the star tracker is mounted comprises: a fixing interface to connect the device to the star tracker, a set of geometric markers configured to, by means of an optical measurement instrument tied to the structure, position a marker tied to the device in the reference marker tied to the structure, an optical simulator comprising a set of optical markers to be measured by the star tracker, making it possible to position the functional trihedron of the star tracker in the trihedron tied to the device, the measurements of position of the functional trihedron in the trihedron tied to the device, and of position of the trihedron tied to the device in the reference trihedron, making it possible to position by calculation the functional trihedron in the reference trihedron.

First claim

The invention claimed is:

1. A device for positioning a functional trihedron of a star tracker in a reference trihedron tied to a structure on which the star tracker is mounted, the device comprising:
a fixing interface intended to connect the device to the star tracker,
a set of geometric markers configured, by an optical measurement instrument tied to the structure, to position a marker tied to the device in the reference marker tied to the structure,
an optical simulator comprising a set of optical markers configured to be measured by the star tracker, to position the functional trihedron of the star tracker in the trihedron tied to the device,
the measurements of position of the functional trihedron in the trihedron tied to the device, and of position of the trihedron tied to the device in the reference trihedron, making it possible to position by calculation the functional trihedron in the reference trihedron.

2. The device according to claim 1 , comprising a control unit configured to:
communicate with the star tracker in such a way as to trigger and recover a measurement of position of the functional trihedron of the star tracker in the trihedron tied to the device,
communicate with the optical measurement instrument in such a way as to trigger and recover the measurement of position of the trihedron tied to the device in the reference trihedron;
determine by calculation the position of the functional trihedron in the reference trihedron.

3. The device according to claim 2 , whose control unit is configured to trigger and recover several successive measurements of position, of the functional trihedron of the star tracker in the trihedron tied to the device, or of the trihedron tied to the device in the reference trihedron, and to determine a mean value thereof.

4. The device according to claim 1 , wherein the set of optical markers of the optical simulator comprises a set of luminous signals measurable by the star tracker.

5. The device according to claim 4 , wherein the set of luminous signals is configured in such a way as to reproduce an image of the celestial canopy, allowing the star tracker to position the functional trihedron of the star tracker in the trihedron tied to the device.

6. The device according to claim 1 , wherein the geometric markers comprise at least one optical cube fixed on the device to allow a position measurement by theodolite.

7. The device according to claim 1 , wherein the geometric markers comprise at least one target fixed on the device and configured to allow a position measurement by photogrammetry or videogrammetry.

8. The device according to claim 1 , wherein the structure is the structure of a spacecraft.

9. The device according to the claim 8 , configured to position the functional trihedron of a star tracker in a reference trihedron tied to the structure of a satellite.

10. An apparatus comprising a star tracker and a positioning device according to claim 1 .

11. A method for positioning a functional trihedron of a star tracker in a reference trihedron tied to a structure on which the star tracker is mounted, by a device according to claim 1 , the method comprising:
communicating with the star tracker to trigger and recover a measurement of position of the functional trihedron of the star tracker in a trihedron tied to the device,
communicating with the optical measurement instrument to trigger and recover the measurement of position of the trihedron tied to the device in the reference trihedron; and
determining by calculation the position of the functional trihedron in the reference trihedron.

12. The method of positioning according to claim 11 , wherein the set of optical markers of the optical simulator comprises a set of luminous signals measurable by the star tracker, and
the method further comprising activating the optical simulator of the device, carried out before communicating with the star tracker.

13. The method of positioning according to claim 11 , wherein the measurement of position of the functional trihedron of the star tracker in the trihedron tied to the device, or of the trihedron tied to the device in the reference trihedron, is repeated several times; and determining the position of the functional trihedron in the reference trihedron comprises calculating a mean of the position measurements.

14. The method of positioning according to claim 11 , comprising a prior step of fixing the star tracker on the structure and/or fixing the device on the star tracker.

Assignees

• Thales Sa

Inventors

• Dazin Sébastien
• Di Giorgio Fabio
• Forestier Damien

Classifications

• B64G1/361 Primary

  using star sensors · CPC title

• G01C21/025

  with the use of startrackers · CPC title

• G01C21/24

  specially adapted for cosmonautical navigation · CPC title

• G01D5/26

  characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light · CPC title

• G01S3/781 Primary

  Details · CPC title