Miniaturized Inertial Measurement Unit and Associated Methods
First Claim
1. An inertial measurement unit comprising:
- a base comprising a plurality of physically distinct sectors;
three sets of angle rate sensors orientable triaxially in a first direction, each set mounted on a different sector of the base orientable normal to the other two and comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
three sets of angle rate sensors orientable triaxially in a second direction opposite the first direction, each set mounted on a different sector of the base orientable normal to the other two and comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
at least one accelerometer positioned on the base adapted to provide six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination; and
means for outputting signals from the six sets of angle rate sensors and the accelerometer to a processor for calculating at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments.
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Accused Products
Abstract
A self-contained, integrated micro-cube-sized inertial measurement unit is provided wherein accuracy is achieved through the use of specifically oriented sensors, the orientation serving to substantially cancel noise and other first-order effects, and the use of a noise-reducing algorithm such as wavelet cascade denoising and an error correcting algorithm such as a Kalman filter embedded in a digital signal processor device. In a particular embodiment, a pair of three sets of angle rate sensors are orientable triaxially in opposite directions, wherein each set is mounted on a different sector of a base orientable normal to the other two and comprising N gyroscopes oriented at 360/N-degree increments, where N≧2. At least one accelerometer is included to provide triaxial data. Signals are output from the angle rate sensors and accelerometer for calculating a change in attitude, position, angular rate, acceleration, and/or velocity of the unit.
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Citations
33 Claims
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1. An inertial measurement unit comprising:
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a base comprising a plurality of physically distinct sectors;
three sets of angle rate sensors orientable triaxially in a first direction, each set mounted on a different sector of the base orientable normal to the other two and comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
three sets of angle rate sensors orientable triaxially in a second direction opposite the first direction, each set mounted on a different sector of the base orientable normal to the other two and comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
at least one accelerometer positioned on the base adapted to provide six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination; and
means for outputting signals from the six sets of angle rate sensors and the accelerometer to a processor for calculating at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of making an inertial measurement unit comprising the steps of:
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providing a base comprising a plurality of physically distinct sectors, the sectors foldable relative to each other;
orienting a first angle rate sensor in a first direction on a first sector of the base and a second angle rate sensor in a second direction opposite the first direction on the first base sector;
orienting a third angle rate sensor in the first direction on a second sector of the base and a fourth angle rate sensor in the second direction on the second base sector;
orienting a fifth angle rate sensor in the first direction on a third sector of the base and a sixth angle rate sensor in the second direction on the third base sector;
wherein each angle rate sensor comprises N gyroscopes oriented at 360/N-degree increments, where N≧
2;
folding the first, the second, and the third base sectors relative to each other so as to be relatively normal to each other;
positioning at least one accelerometer on the base, the accelerometer adapted to provide six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination; and
outputting signals from the angle rate sensors and the accelerometer; and
calculating from the output signals at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method of calculating from inertial measurement unit data at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments comprising the steps of:
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receiving angle rate data from three sets of angle rate sensors oriented triaxially in a first direction on an inertial measurement unit, each set comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
receiving angle rate data from three sets of angle rate sensors oriented triaxially in a second direction opposite the first direction on the inertial measurement unit, each set comprising N gyroscopes oriented at 360/N-degree increments, where N≧
2;
receiving accelerometer data comprising six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination, the accelerometer on the inertial measurement unit; and
calculating from the received angle rate data and the received accelerometer data at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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32. An inertial measurement unit comprising:
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a substantially planar base comprising a plurality of physically distinct sectors foldable relative to each other;
a first angle rate sensor orientable in a first direction and mounted on a first sector of the base;
a second angle rate sensor orientable in a second direction and mounted on a second sector of the base;
a third angle rate sensor orientable in a third direction and mounted on a third sector of the base;
wherein;
the first, the second, and the third base sectors are different sectors;
the first, the second, and the third direction are normal to each other;
and the first, the second, and the third angle rate sensors are orientable by folding the respective first, second, and third base sectors relative to each other to form a unitary structure;
an accelerometer positioned on the base adapted to provide six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination; and
means for outputting signals from the first, the second, and the third angle rate sensors and the accelerometer to a processor for calculating at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments.
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33. A method of making an inertial measurement unit comprising the steps of:
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providing a substantially planar base comprising a plurality of physically distinct sectors foldable relative to each other;
mounting a first angle rate sensor on a first sector of the base;
mounting a second angle rate sensor on a second sector of the base;
mounting a third angle rate sensor on a third sector of the base;
positioning an accelerometer on the base, the accelerometer adapted to provide six signals, three of the signals containing triaxial accelerometer data and three of the signals containing data for determining inclination; and
folding the respective first, second, and third base sectors relative to each other to form a unitary structure wherein the first, the second, and the third base sectors are normal to each other.
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Specification