Heading for a hybrid navigation solution based on magnetically calibrated measurements
First Claim
1. A method for determining a heading for a hybrid navigation system with magnetometer aiding, the method comprising:
- receiving signals from a plurality of global navigation satellite system (GNSS) satellites at a location corresponding to an object;
obtaining three-dimensional inertial measurements from one or more inertial sensors corresponding to the object;
obtaining three-dimensional magnetic measurements from one or more magnetometers corresponding to the object;
estimating states for position, velocity, roll, pitch, and heading of the object with a magnetic calibration filter;
estimating states for calibration of the three-dimensional inertial measurements with the magnetic calibration filter;
estimating states for bias and drift of a GNSS clock with the magnetic calibration filter; and
estimating states for pseudorange biases for the signals from the GNSS satellites with the magnetic calibration filterestimating nine soft iron bias states and three hard iron bias states for biases of the three-dimensional magnetic measurements with the magnetic calibration filter using the three-dimensional inertial measurements, data from the signals from the plurality of GNSS satellites, and the three-dimensional magnetic measurements;
calculating an artificial heading for the object as a function of
ψ
ma=f(θ
,φ
,mcalBx,mcalBy,mcalBz,ψ
dec)where φ
is the roll estimate from a main navigation filter, θ
is the pitch estimate from the main navigation filter, ψ
dec is the magnetic declination, and mcalBx, mcalBy, and mcalBz are calibrated magnetic measurements with components x, y, and z in the body frame, respectively, wherein mcalB is calculated as a function of
mcalB=f(Dmag,{tilde over (m)}B,bmagB)where Dmag is the magnetic bias state matrix corresponding to soft iron biases, bmagB is the magnetic bias state vector corresponding to hard iron biases, and {tilde over (m)}B is the three-dimensional magnetic measurements;
estimating a main navigation solution for the object with the main navigation filter using the three-dimensional inertial measurements, data from the signals from a plurality of GNSS satellites, and the artificial heading.
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Abstract
One embodiment is directed towards a method for determining a heading for a hybrid navigation system with magnetometer aiding. The method includes receiving signals from a plurality of GNSS satellites, obtaining three-dimensional inertial measurements from one or more inertial sensors, and obtaining three-dimensional magnetic measurements from one or more magnetometers. Magnetic bias states are estimated for the three-dimensional magnetic measurements with a magnetic calibration filter using the three-dimensional inertial measurements, data from the signals from the plurality of GNSS satellites, and the three-dimensional magnetic measurements. An artificial heading is calculated based on the magnetic bias states. A main navigation solution can be estimated with a main navigation filter using the three-dimensional inertial measurements, data from the signals from a plurality of GNSS satellites, and the artificial heading.
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Citations
19 Claims
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1. A method for determining a heading for a hybrid navigation system with magnetometer aiding, the method comprising:
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receiving signals from a plurality of global navigation satellite system (GNSS) satellites at a location corresponding to an object; obtaining three-dimensional inertial measurements from one or more inertial sensors corresponding to the object; obtaining three-dimensional magnetic measurements from one or more magnetometers corresponding to the object; estimating states for position, velocity, roll, pitch, and heading of the object with a magnetic calibration filter; estimating states for calibration of the three-dimensional inertial measurements with the magnetic calibration filter; estimating states for bias and drift of a GNSS clock with the magnetic calibration filter; and estimating states for pseudorange biases for the signals from the GNSS satellites with the magnetic calibration filter estimating nine soft iron bias states and three hard iron bias states for biases of the three-dimensional magnetic measurements with the magnetic calibration filter using the three-dimensional inertial measurements, data from the signals from the plurality of GNSS satellites, and the three-dimensional magnetic measurements; calculating an artificial heading for the object as a function of
ψ
ma=f(θ
,φ
,mcalBx,mcalBy,mcalBz,ψ
dec)where φ
is the roll estimate from a main navigation filter, θ
is the pitch estimate from the main navigation filter, ψ
dec is the magnetic declination, and mcalBx, mcalBy, and mcalBz are calibrated magnetic measurements with components x, y, and z in the body frame, respectively, wherein mcalB is calculated as a function of
mcalB=f(Dmag,{tilde over (m)}B,bmagB)where Dmag is the magnetic bias state matrix corresponding to soft iron biases, bmagB is the magnetic bias state vector corresponding to hard iron biases, and {tilde over (m)}B is the three-dimensional magnetic measurements; estimating a main navigation solution for the object with the main navigation filter using the three-dimensional inertial measurements, data from the signals from a plurality of GNSS satellites, and the artificial heading. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A navigation system for an object comprising:
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one or more processing devices; one or more global navigation satellite system (GNSS) receivers coupled to the one or more processing devices, the one or more GNSS receivers configured to obtain pseudorange measurements corresponding to a location of the object; one or more inertial measurement units (IMUs) coupled to the one or more processing devices, the one or more IMUs configured to obtain three-dimensional inertial measurements corresponding to the object; one or more magnetometers coupled to the one or more processing devices, the one or more magnetometers configured to obtain three-dimensional magnetic measurements of the magnetic field at a location of the object; and one or more memory devices coupled to the one or more processing devices and including instructions which, when executed by the one or more processing devices, cause the one or more processing devices to; estimate states for position, velocity, roll, pitch, and heading of the object with a magnetic calibration filter; estimate states for calibration of the three-dimensional inertial measurements with the magnetic calibration filter; estimate states for calibration of a GNSS clock with the magnetic calibration filter; and estimate states for pseudorange biases for the signals from the GNSS satellites with the magnetic calibration filter; estimate nine soft iron bias states and three hard iron bias states for biases of the three-dimensional magnetic measurements with the magnetic calibration filter using the three-dimensional inertial measurements for a prediction step, and using data from the one or more GNSS receivers and the three-dimensional magnetic measurements as a measurement vector; calculate an artificial heading for the object as a function of
ψ
ma=f(θ
,φ
,mcalBx,mcalBy,mcalBz,ψ
dec)where φ
is the roll estimate from a main navigation filter, θ
is the pitch estimate from the main navigation filter, ψ
dec is the magnetic declination, and mcalBx, mcalBy, and mcalBz are calibrated magnetic measurements with components x, y, and z in the body frame, respectively, wherein mcalB is calculated as a function of
mcalB=f(Dmag,{tilde over (m)}B,bmagB)where Dmag is the magnetic bias state matrix corresponding to soft iron biases, bmagB is the magnetic bias state vector corresponding to hard iron biases, and {tilde over (m)}B is the three-dimensional magnetic measurements; and estimate a main navigation solution for the object with the main navigation filter using the three-dimensional inertial measurements for a prediction step, and using data from the one or more GNSS receivers and the artificial heading as a measurement vector. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A computer readable medium including instructions which, when executed by one or more processing devices, cause the one or more processing devices to:
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estimate magnetic bias states for biases of three-dimensional magnetic measurements with a magnetic calibration filter using three-dimensional inertial measurements for a prediction step, and using data from signals from a plurality of global navigation satellite system (GNSS) satellites and the three-dimensional magnetic measurements as a measurement vector, wherein estimate magnetic bias states includes estimate nine states for soft iron biases and three states for hard iron biases; calculate an artificial heading, ψ
ma, for an object as
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Specification