NAVIGATION DEVICE AND PROCESS INTEGRATING SEVERAL HYBRID INERTIAL NAVIGATION SYSTEMS

• US 20130006528A1
• Filed: 06/27/2012
• Published: 01/03/2013
• Est. Priority Date: 06/29/2011
• Status: Active Grant

• Current Assignee: Exail
• Original Assignee: iXBlue, Inc.
• Inventors: NAPOLITANO, Fabien
• Granted Patent: US 8,898,013 B2
• Time in Patent Office: Days
• 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), said inertial measuring unit (IMU-1, IMU-2) being adapted to deliver at least one signal representative of an inertial measurement, and each hybrid navigation system comprising at least one calculator (CALC-H1, CALC-H2) configured in such a manner to hybridize said at least one signal representative of an inertial measurement 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 detection of good operating condition and the weighting of said hybrid navigation systems (INH1, INH2), said module (MOD) being configured in such a manner to receive, on the one hand, said at least one auxiliary signal, and on the other hand, said hybrid signals (DATA1, DATA2) at the output of each hybrid navigation system (INH1, INH2), respectively, and to deduce therefrom at least one indicator of good operating condition (STATUS) and a weighting coefficient for each hybrid navigation system (INH1, INH2), said weighting coefficient being respectively calculated as a function of a 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. A hybrid navigation device for a vehicle according to claim 1, wherein the good-working-condition detection and weighting module (MOD) comprises, for each hybrid navigation system (INH1, INH2), a calculation block (Calc-V1, Calc-V2) configured to calculate a residue between said hybrid signal (DATA1, DATA2) and said auxiliary signal and to calculate a weighting coefficient of said hybrid signal as a function of the likelihood of said residue or as a function the log-likelihood of said residue.

3. A 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.

4. A hybrid navigation device for a vehicle according to claim 2, 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.

5. A 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), on the one hand, the navigation states of said hybrid navigation system, and on the other hand, an error estimator for said navigation states.

6. A hybrid navigation device for a vehicle according to claim 5, 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.

7. A 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:

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

9. A 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).

10. A method of navigation for a vehicle, based on the use of a device according to claim 1, and comprising the following steps:

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 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 an indicator of good operating condition and a weighting coefficient for each hybrid navigation system (INH1, INH2) as a function, on the one hand, of the at least one auxiliary signal, and on the other hand, of the hybrid signals (DATA1, DATA2) at the output of each hybrid navigation system (INH1, INH2), respectively, 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.

11. A method of navigation according to claim 10, comprising the following steps for each hybrid navigation system:

calculating a residue between said hybrid signal and said auxiliary signal, and

calculating a respective weighting coefficient of said hybrid signal based on the likelihood of said residue.

12. A hybrid navigation device for a vehicle according to claim 2, 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.