Method and device for magnetic field measurement by magnetometers
AssigneeSysnav
InventorsDavid Vissiere, Mathieu Hillion
Life of this patent
Estimating the term…
Abstract
Magnetic field measurement by a set of magnetometers which are linked to a same moveable support and which have different orientations of eigendirections with respect to this support A processor determines, during a measurement in a given position and orientation of the support and of the set of magnetometers, for each magnetometer, of the orientation deviation between the eigendirections of the magnetometer and a candidate magnetic field, the magnetometer for which this deviation is minimal, the magnetic field measured by this sensor being selected as the magnetic field measured by the set of magnetometers. The magnetometers are distributed in space in order to cover a maximum of different orientations.
Claims12
A method comprising:
- measuring candidate magnetic fields using different magnetometers included in a moving device, wherein each of the different magnetometers have different eigendirections,
- computing a set of deviations respectively associated with the different magnetometers, wherein each of the deviations is computed as follows:
- e
- j
- =
- min
- i
- ∈
- 〚
- 1.
- .
- n
- 〛
-
- (
- d
- l
- J
- →
- ,
- B
- B
- J
- →
- )
- wherein
- ej is a respective one of the deviations associated with a j-th magnetometer among the different magnetometers,
- ({right arrow over (diJ)})i∈[[1 . . . n]] is a vector representing an i-th eigendirection of the j-th magnetometer,
- {right arrow over (BBJ)} is a vector representing the candidate magnetic field measured by the j-th magnetometer,
- ({right arrow over (diJ)},{right arrow over (BBJ)}) is an angle between {right arrow over (diJ)}, and {right arrow over (BBJ)},
- n is an integer greater than 1,
- selecting a magnetometer among the different magnetometers, wherein the selected magnetometer is associated with the respective one of the deviations that is minimal and wherein the selected magnetometer has measured a magnetic field least impacted by non-linearities, and
- using by a magneto-inertial navigation system the magnetic field measured by the selected magnetometer wherein said magnetic field is the least impacted by non-linearities without having resorted to a specific calibration to treat said non-linearities.
A device comprising magnetometers each having different eigendirections, the magnetometers being configured to measure candidate magnetic fields, wherein the device further comprises a processor that is configured to:
- compute the deviations respectively associated with the magnetometers, wherein each of the deviations is computed as follows:
- e
- j
- =
- min
- i
- ∈
- 〚
- 1.
- .
- n
- 〛
-
- (
- d
- l
- J
- →
- ,
- B
- B
- J
- →
- )
- wherein
- ej is a respective one of the deviations associated with a j-th magnetometer among the magnetometers,
- ({right arrow over (diJ)})i∈[[1 . . . n]] is a vector representing an i-th eigendirection of the j-th magnetometer,
- {right arrow over (BBJ)} is a vector representing the candidate magnetic field measured by the j-th magnetometer,
- ({right arrow over (diJ)},{right arrow over (BBJ)}) is an angle between {right arrow over (diJ)}, and {right arrow over (BBJ)};
- n is an integer greater than 1,
- select a magnetometer among the magnetometers, wherein the selected magnetometer is associated with the respective one of the deviations that is minimal and wherein the selected magnetometer corresponds to the magnetometer having measured a magnetic field least impacted by non-linearities, and
- use by a magneto-inertial navigation system the magnetic field measured by the selected magnetometer wherein said magnetic field is the least impacted by non-linearities without having resorted to a specific calibration to treat said non-linearities.
Dependencies are inferred from the claim text.