Measurement by gyroscopic system

• US 7,997,134 B2
• Filed: 04/10/2008
• Issued: 08/16/2011
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Safran Electronics & Defense
• Original Assignee: Sagem Defense Securite (Safran SA)
• Inventors: Carre, Arnauld, Lignon, Christian
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US12/100,832
• Publication Number:
  US 20090158846A1
• Time in Patent Office: 1,223 Days
• Field of Search: 73/13.7, 73/13.8, 735/041.2, 735/040.4, 735/041.3, 735/041.4, 735/10, 735/11, 702 87- 88, 702/104
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/567 using the phase shift of a vibration node or antinode

Abstract

A gyroscopic system is disclosed comprising at least a vibrating gyroscope, as a first mechanism of angle measurement, designed to provide a first measurement of angle values according to a measurement axis; and a second mechanism of angle measurement, designed to provide a second measurement of angle values according to said measurement axis. First angle values through the first angle measurement mechanism vibrating in a current vibration position and second angle values through the second angle measurement mechanism are provided simultaneously; and from these second angle values corrected on the basis of a comparison of the first and second angle values are deduced. Then the vibration position of the first angle measurement mechanism is changed from the current position to another vibration position. First angle values through the first angle measurement mechanism and second angle values through the second angle measurement mechanism are then provided simultaneously; and from these first angle values corrected on the basis of a comparison of the first and second angle values are deduced.

Claims

1. A measurement method by a gyroscopic system comprising at least:

a vibrating gyroscope, as a first means of angle measurement, designed to change the vibration position of the vibrating gyroscope among a plurality of vibration positions and to provide a first measurement of angle values according to a measurement axis in one of the vibration positions of said plurality of vibration positions, said first means of angle measurement having a first zero reference as angle value; and

a second means of angle measurement, designed to provide a second measurement of angle values according to said measurement axis, said second means of angle measurement having a second zero reference as angle value;

said measurement method comprising the following steps to implement a change in vibration position of the first angle measurement means;

(a) in a first period of time, simultaneously providing first angle values through the first angle measurement means vibrating in a current vibration position from the plurality of vibration positions and second angle values through the second angle measurement means, and deducing, from the first angle values and the second angle values, corrected second angle values by adapting the second zero reference on the basis of a comparison of the first and second angle values obtained in said first period of time;

(b) in a second period of time, changing the vibration position of the first angle measurement means from the current position to another vibration position from said plurality of vibration positions;

(c) in a third period of time, simultaneously providing first angle values through the first angle measurement means and second angle values through the second angle measurement means, and deducing, from the first angle values and the second angle values, corrected first angle values by adapting the first zero reference on the basis of a comparison of the first and second angle values obtained in said third period of time.

2. The measurement method according to claim 1, in which the gyroscopic system provides the following angle values:

before and during the step (a) and after the step (c), the angle values provided by the first angle measurement means;

during the steps (b) and (c), the angle values provided by the second angle measurement means.

3. The measurement method according to claim 1, in which a change in vibration position of the first angle measurement means according to the steps (a) to (c) is repeated several times in succession.

4. The measurement method according to claim 1, said gyroscopic system comprising a number N of vibrating gyroscopes, N being an integer greater than or equal to 3, the N gyroscopes being designed to change the vibration position of the N gyroscopes among a plurality of vibration positions and to provide respective measurements of angle values according to respective measurement axes in respective vibration positions of said plurality of vibration positions;

the first measurement means corresponding to any one of N vibrating gyroscopes, the second measurement means corresponding to any set of gyroscopes among the N−

1 other gyroscopes of the system and being designed to provide an angle measurement according to the measurement axis of the first measurement means and relative to the second zero reference.

5. The measurement method according to claim 4, in which at least two of the measurement axes are perpendicular.

6. The measurement method according to claim 4, in which N is equal to 3, said three vibrating gyroscopes have two by two respectively coplanar and nonlinear measurement axes.

7. The measurement method according to claim 4, in which N is equal to 3 and in which the three gyroscopes are situated in the same plane such that the respective measurement axes form an angle approximately equal to 120°

.

8. The measurement method according to claim 4, in which N is equal to 4 and in which the four gyroscopes are situated in space in such a way that their respective measurement axes of the four gyroscopes are oriented according to the four trisectors of space.

9. The measurement method according to claim 4, in which N is equal to 4 and in which said four vibrating gyroscopes have three by three noncoplanar and two by two noncolinear measurement axes.

10. The measurement method according to claim 1, in which the vibration positions of the plurality of vibration positions are successively separated by an angle value corresponding to 360°

divided by an integer.

11. The measurement method according to claim 1, in which the vibration positions of the plurality of vibration positions are determined to distribute the vibration positions used between 0 and 2π

radians.

12. The measurement method according to claim 1, in which at least one of the corrected first and second angle values are obtained by furthermore taking a scaling factor into account.

13. A gyroscopic measurement system comprising at least:

a vibrating gyroscope, as a first means of angle measurement, designed to change the vibration position of the vibrating gyroscope among a plurality of vibration positions and to provide a first measurement of angle values according to a measurement axis in one of the vibration positions of said plurality of vibration positions, said first means of angle measurement having a first zero reference and providing angle first values; and

a second means of angle measurement, designed to provide a second measurement of angle values according to said measurement axis, said second means of angle measurement having a second zero reference as angle value and providing second angle values;

said gyroscopic system furthermore comprising;

a unit for correcting the second angle values, designed to provide corrected second angle values by adapting the second zero reference on the basis of a comparison of the first and second angle values obtained in a period of time;

a unit for correcting the first angle values, designed to provide corrected first angle values by adapting the first zero reference on the basis of a comparison of the first and second angle values obtained in another period of time;

said units for correcting the first and second values being employed during a change in vibration position of at least the first means of angle measurement.

14. The gyroscopic measurement system according to claim 13, in which the first angle measurement means and the second angle measurement means alternately provide angle values during a change in vibration position of the first angle measurement means.

15. The gyroscopic measurement system according to claim 13, comprising a number N of vibrating gyroscopes, N being an integer greater than or equal to 3, the N gyroscopes being designed to change the vibration position of the N gyroscopes among a plurality of vibration positions and to provide respective measurements of angle values according to respective measurement axes in respective vibration positions of said plurality of vibration positions, the first measurement means corresponding to any one of N vibrating gyroscopes, the second measurement means corresponding to any set of gyroscopes among the N−

1 other gyroscopes of the system and being designed to provide an angle measurement according to the measurement axis of the first measurement means and relative to the second zero reference.

16. The measurement system according to claim 15, in which N is equal to 3, said three vibrating gyroscopes having have two by two respectively coplanar and nonlinear measurement axes.

17. The measurement system according to claim 15, in which N is equal to 3 and in which the three gyroscopes are situated in the same plane such that the respective measurement axes form an angle approximately equal to 120°

.

18. The measurement system according to claim 15, in which N is equal to 4 and in which the four gyroscopes are situated in space in such a way that the respective measurement axes of the four gyroscopes are oriented according to the four trisectors of space.

19. The measurement system according to claim 15, in which N is equal to 4, said four vibrating gyroscopes having three by three noncoplanar and two by two noncolinear measurement axes.