Navigation device and process integrating several hybrid inertial navigation systems

• US 8,898,013 B2
• Filed: 06/27/2012
• Issued: 11/25/2014
• Est. Priority Date: 06/29/2011
• Status: Active Grant

• Current Assignee: Exail
• Original Assignee: iXBlue, Inc.
• Inventors: Napolitano, Fabien
• Primary Examiner(s): Cheung, Calvin
• Assistant Examiner(s): Martinez Borrero, Luis A
• Application Number:
  US13/534,760
• Publication Number:
  US 20130006528A1
• Time in Patent Office: 881 Days
• Field of Search: 701/207, 701/213, 701/220, 701/472, 701/41, 701/7, 701/216, 701/468, 701/501, 701/1, 701/113, 701/36, 701/409, 701/411, 342/357.12, 342/357.03, 342/357.14, 342/357.44, 342/386, 342/464, 342/357.28, 342/357.3, 342/357.31, 342/357.34, 700/280, 370/210, 455/133, 455/277.1, 455/280, 455/436, 455/444, 455/449, 455/560, 455/562.1
• US Class Current: 701/505
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems

Abstract

A hybrid navigation device includes at least one auxiliary sensor adapted to deliver at least one auxiliary signal and a plurality of hybrid navigation systems, each including at least one inertial navigation system and one calculator configured to form an hybrid signal at the output of each hybrid navigation system. The hybrid navigation device includes a module for the detection of good operating condition and the weighting of the hybrid navigation systems, the module being configured to receive the at least one auxiliary signal, and the hybrid signals of each hybrid navigation system, respectively, to deduce therefrom an indicator of good operating condition and a weighting coefficient for each hybrid navigation system, and to calculate a weighted hybrid signal as a function of the hybrid signals and of the weighting coefficients of each hybrid navigation system, respectively.

Claims

1. A hybrid navigation device for a vehicle, comprising:

at least one auxiliary sensor (DET1) adapted to deliver at least one auxiliary signal representative of an auxiliary navigation parameter of the vehicle, and

a plurality of hybrid navigation systems (INH1, INH2),

each hybrid navigation system comprising at least one inertial navigation system comprising at least one inertial measuring unit (IMU-1, IMU-2) including three gyroscopes and three accelerometers and, said inertial measuring unit (IMU-1, IMU-2) being adapted to deliver corresponding instantaneous rotation and acceleration signals representative of inertial measurements respectively made by the three gyroscopes and the three accelerometers, and each hybrid navigation system comprising at least one calculator (CALC-H1, CALC-H2) configured in such a manner to hybridize at least one of said signals representative of inertial measurements with said at least one auxiliary signal, to form a hybrid signal at the output of each hybrid navigation system (DATA1, DATA2),

characterized in that;

said hybrid navigation device comprises a module (MOD) for the weighting of said hybrid navigation systems (INH1, INH2), said module (MOD) being configured in such a manner to receive, said at least one auxiliary signal and said hybrid signals (DATA1, DATA2) at the output of each hybrid navigation system (INH1, INH2), respectively, to calculate, for each hybrid navigation system, a likelihood of a residue between said hybrid signal output from the concerned hybrid navigation system and said auxiliary signal using a variance estimate of said hybrid signal and a variance estimate of the auxiliary signal, and to deduce therefrom a weighting coefficient for each hybrid navigation system (INH1, INH2), said weighting coefficient being respectively calculated as a function of the likelihood of the residue between said hybrid signal (DATA1, DATA2) and said auxiliary signal, and said module (MOD) being configured in such a manner to calculate a weighted hybrid signal (DATAOPT) as a function of said hybrid signals (DATA1, DATA2) and of the weighting coefficients of each hybrid navigation system, respectively.

2. The hybrid navigation device for a vehicle according to claim 1, comprising a plurality of hybrid inertial systems (INH1, INH2) and a plurality of auxiliary sensors, wherein each inertial system is hybridized with a different auxiliary sensor.

3. The hybrid navigation device for a vehicle according to claim 1, comprising a plurality of hybrid inertial systems (INH1, INH2) and a plurality of auxiliary sensors, wherein at least one hybrid inertial system (INH1, INH2) is hybridized with several auxiliary sensors, and wherein the associated calculation block (Calc-V1, Calc-V2) is configured in such a manner to calculate a whole likelihood of a set of sensors and/or a partial likelihood relating to a sub-set of sensors from the set of sensors hybridized to the hybrid inertial system.

4. The hybrid navigation device for a vehicle according to claim 1, wherein each calculator (CALC-H1, CALC-H2) is configured in such a manner to calculate and to transmit to the detection module (MOD the navigation states of said hybrid navigation system and an error estimator for said navigation states.

5. The hybrid navigation device for a vehicle according to claim 4, wherein the error estimator for the navigation states comprises the covariance matrix of the navigation states or a part of the covariance matrix of the navigation states.

6. The hybrid navigation device for a vehicle according to claim 1, wherein the device comprises two hybrid inertial systems (INH1, INH2) and wherein the weighted hybrid signal (DATAOPT) is calculated as a function of said hybrid signals (DATA1, DATA2) and of the respective weighting coefficients of each hybrid navigation system (INH1, INH2), according to the following formula:

7. The hybrid navigation device for a vehicle according to claim 6, wherein the error covariance SOPT of the weighted hybrid signal DATAOPT is obtained by the following formula:

8. The hybrid navigation device for a vehicle according to claim 1, wherein said calculation blocks (Calc-V1, Calc-V2) are integrated in the calculator(s) (CAL-H1, CALC-H2) of one or a plurality of hybrid inertial systems (INH1, INH2).

9. The hybrid navigation device for a vehicle according to claim 1, comprising a plurality of hybrid inertial systems (INH1, INH2) and a plurality of auxiliary sensors, wherein each inertial system is hybridized with a different auxiliary sensor.

10. The hybrid navigation device according to claim 1, wherein the weighting module is configured in such a manner to deduce, from the auxiliary signal and the hybrid signals, at least one indicator of good operating condition.

11. A method of navigation for a vehicle comprising:

acquiring by at least one auxiliary sensor (DET1) at least one auxiliary signal representative of a navigation parameter of the vehicle, and

acquiring a plurality of signals representative, respectively, of an inertial measurement, by means of a plurality of hybrid navigation systems (INH1, INH2),

calculating a hybrid signal at the output of each hybrid navigation system (DATA1, DATA2) based on at least one auxiliary signal and a signal representative of an inertial measurement,

calculating, for each hybrid navigation system, a likelihood of a residue between said hybrid signal output from the concerned hybrid navigation system and said auxiliary signal using a variance estimate of said hybrid signal and a variance estimate of the auxiliary signal,

calculating a weighting coefficient for each hybrid navigation system (INH1, INH2) as a function of the likelihood of the residue calculated for the concerned hybrid navigation system, and

calculating a weighted hybrid signal (DATAOPT) as a function of said hybrid signals (DATA1, DATA2) and of the weighting coefficients of each hybrid navigation system, respectively.

12. The navigation method according to claim 11, comprising calculating an indicator of good operating condition as a function of the auxiliary signal and the hybrid signals.