Attitude measurement using a single GPS receiver with two closely-spaced antennas
First Claim
1. An motion characterization system, comprising:
- two antennas, mounted to a rigid body, to receive navigation signals;
a collection of motion sensing devices, including rate gyroscopes providing poorer than ten degrees per hour accuracy, mounted on the rigid body to provide electrical signals providing motion information; and
a processor electrically coupled to process electrical signals from the antennas and the motion sensing devices to provide an attitude measurement of the rigid body under arbitrary motion conditions.
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Accused Products
Abstract
A system determines three-dimensional attitude of a moving platform using signals from two closely spaced Global Positioning System (GPS) antennas. The system includes three rate gyroscopes and three accelerometers rigidly mounted in a fixed relationship to the platform to aid in determining the attitude. The system applies signals from a first of the two GPS antennas to sufficient channels of a GPS receiver to support navigation. The system applies signals from a second of the two GPS antennas to the remaining receive channels, which are configured to support interferometry. The system optimally selects the navigation and interferometry channels to provide an interferometric heading solution. The system resolves the ambiguity normally associated with the interferometric heading solution by having the closely spaced GPS antennas and using interferometry to refine a coarse heading estimate from a GPS plus Inertial Measurement Unit (IMU) transfer alignment solution. The system achieves close sub-meter spacing of the two GPS antennas by merging many temporal interferometric measurements that result from an attitude memory provided by the IMU time-history solution.
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Citations
44 Claims
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1. An motion characterization system, comprising:
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two antennas, mounted to a rigid body, to receive navigation signals;
a collection of motion sensing devices, including rate gyroscopes providing poorer than ten degrees per hour accuracy, mounted on the rigid body to provide electrical signals providing motion information; and
a processor electrically coupled to process electrical signals from the antennas and the motion sensing devices to provide an attitude measurement of the rigid body under arbitrary motion conditions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43)
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13. A method for determining attitude of a rigid body, comprising:
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receiving navigation signals at the rigid body;
measuring motion of the rigid body, including rate with poorer than ten degrees per hour accuracy, and providing corresponding motion signals; and
processing the navigation signals and motion signals to provide an attitude measurement of the rigid body under arbitrary motion conditions.
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16. An motion characterization system, comprising:
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platform means;
means for receiving navigation signals at said platform means;
means for sensing motion of said platform means and for providing associated motion signals, including rate of said platform means with an accuracy of poorer than ten degrees per hour; and
means for processing the navigation signals and the motion signals to provide an attitude measurement of said platform means under arbitrary motion conditions.
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17. A mobile system, comprising:
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a platform;
a motion characterization system including;
(i) a first navigation antenna and second navigation antenna coupled to the platform to receive navigation carrier signals, (ii) a plurality of motion sensing devices coupled to the platform to provide motion signals representative of motion of the platform, and (iii) a processor (a) coupled to the antennas to make range and carrier phase measurements of the navigation carrier signals at a plurality of epochs defining the navigation carrier signals and to segment the range and carrier phase measurements for the navigation carrier signals into a navigation set and an interferometry set, the sets having at least one navigation carrier signal for a plurality of navigation epochs and supporting interferometry calculations and (b) coupled to the motion sensing devices to receive the motion signals and to convert the motion signals into measurements of platform motion for a plurality of epochs defined for the motion signals, the processor determining a navigation solution including position and attitude of the platform from the range and carrier phase measurements for the navigation carrier signals and from measurements of platform motion developed from the motion signals; and
a subsystem in communication with the motion characterization system responsive to the navigation solution.
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35. A method for determining attitude of a stationary or moving platform, comprising:
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receiving navigation carrier signals;
making range and carrier phase measurements of the navigation carrier signals at a plurality of navigation system epochs defining the navigation carrier signals;
segmenting the range and carrier phase measurements for the navigation carrier signals into a navigation set and an interferometry set, the sets (i) having at least one navigation carrier signal for a plurality of the navigation system epochs and (ii) supporting interferometry calculations;
receiving motion signals representing motion of the platform;
converting the motion signals into measurements of platform motion for a plurality of epochs defined for the motion signals; and
determining a navigation solution including position and attitude of the platform from the range and carrier phase measurements for the navigation carrier signals and from the measurements of platform motion developed from the motion signals.
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44. An apparatus for determining attitude of a platform under arbitrary motion conditions, comprising:
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means for receiving navigation carrier signals;
means for making range and carrier phase measurements of the navigation carrier signals at a plurality of epochs defining the navigation carrier signals;
means for segmenting the range and carrier phase measurements for the navigation carrier signals into a navigation set and an interferometry set, the sets (i) having at least one navigation carrier signal for a plurality of navigation system epochs and (ii) supporting interferometry calculations;
means for converting the motion signals into measurement of platform motion for a plurality of navigation system epochs defined for the motion signals; and
means for determining a navigation solution including position and attitude of the platform from the range and carrier phase measurements of platform motion developed from the motion signals.
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Specification