Calibration of multi-axis accelerometer in vehicle navigation system
First Claim
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1. A vehicle navigation system comprising:
- a multiple-axis inertial sensor generating a plurality of sensor signals, each associated with one of said sensor axes;
a transformation matrix relating said plurality of signals to said vehicle axes; and
a processor transforming said plurality of signals into motion information correlating to vehicle axes.
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Abstract
A navigation system includes a multi-axis accelerometer which can be installed in the vehicle in any unknown orientation. The orientation of the axes of the accelerometer is automatically determined by the navigation system. The signals from the accelerometer are then used to propagate the position of the vehicle.
177 Citations
23 Claims
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1. A vehicle navigation system comprising:
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a multiple-axis inertial sensor generating a plurality of sensor signals, each associated with one of said sensor axes;
a transformation matrix relating said plurality of signals to said vehicle axes; and
a processor transforming said plurality of signals into motion information correlating to vehicle axes. - View Dependent Claims (2, 3, 4, 5)
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6. A vehicle navigation system comprising:
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an inertial sensor generating a plurality of sensor signals each associated with a sensor axis of said sensor, said inertial sensor mounted in an unknown orientation in a vehicle;
a processor programmed to determine a gravity orientation of said sensor relative to gravity and determining a longitudinal orientation of said sensor relative to a longitudinal axis of a vehicle; and
means for propagating a position of a vehicle based upon said plurality of sensor signals, said gravity orientation and said longitudinal orientation. - View Dependent Claims (7)
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8. A vehicle navigation system comprising:
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an inertial sensor generating a plurality of sensor signals each associated with a sensor axis of said sensor, said inertial sensor mounted in an unknown orientation in a vehicle;
a transformation matrix relating said plurality of signals to axes of said vehicle; and
means for propagating a position of a vehicle based upon said plurality of sensor signals. - View Dependent Claims (9, 10, 11)
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12. A method for calibrating an inertial sensor in a vehicle navigation system including the steps of:
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a) receiving a plurality of signals from said inertial sensor;
b) generating a transformation matrix based upon said plurality of signals; and
c) transforming said plurality of signals from said inertial sensor into a reference frame of the vehicle. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
mounting said inertial sensor in the vehicle in an unknown orientation relative to said vehicle; and
determining said orientation of said inertial sensor relative to the vehicle based upon said plurality of signals.
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14. The method of claim 13 wherein the inertial sensor is a multiple axis accelerometer, said method further including the steps of:
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d) determining a gravitational direction relative to the axes of the accelerometer; and
e) transforming said plurality of signals in said step c) based upon said step d).
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15. The method of claim 14 further including the steps of:
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determining that the veh icle is stationary; and
performing said step d) while the vehicle is determined to be stationary.
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16. The method of claim 15 further including the steps of:
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d) performing a predetermined maneuver with said vehicle;
e) receiving said plurality of signals in said step a) during said step d); and
f) determining the orientation of the sensor in the vehicle based upon said step e).
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17. The method of claim 16 wherein said step d) further includes the step of accelerating the vehicle along a longitudinal axis.
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18. The method of claim 17 further including the steps of:
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determining the orientation of the sensor relative to a longitudinal axis of the vehicle;
determining the orientation of the sensor relative to gravity; and
determining the orientation of the sensor relative to a lateral axis of the vehicle, generally orthogonal to the longitudinal axis and gravity.
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19. The method of claim 18 further including the steps of propagating a position of the vehicle based upon the transformed signals from said step c).
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20. A method for calibrating an inertial sensor mounted in an unknown orientation in a vehicle navigation system including the steps of:
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a) determining a gravity orientation of the inertial sensor relative to gravity based upon a first plurality of signals from the sensor;
b) determining a longitudinal orientation of the inertial sensor relative to a longitudinal axis of the vehicle based upon a second plurality of signals from the inertial sensor; and
c) transforming a third plurality of signals from said inertial sensor into a reference frame of the vehicle. - View Dependent Claims (21, 22, 23)
determining that the vehicle is stationary; and
performing said step a) while the vehicle is determined to be stationary.
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22. The method of claim 21 further including the steps of:
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d) performing a predetermined maneuver with said vehicle;
e) receiving said second plurality of signals during said step d); and
f) determining the orientation of the sensor in the vehicle based upon said step e).
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23. The method of claim 22 wherein said step d) further includes the step of accelerating the vehicle along the longitudinal axis of the vehicle.
Specification