Nadir/zenith inertial pointing assistance for two-axis gimbals
First Claim
1. A method of azimuthal pointing of a line of sight (LOS), comprising:
- measuring, at a two-axis gimbal having an azimuth gimbal, an elevation gimbal, and a line of sight and kinematically coupled to a moveable platform;
an acceleration of the moveable platform in an inertial frame of the line of sight, due to a motion of the moveable platform; and
an acceleration of the azimuth gimbal relative to the platform, due to the motion of the moveable platform;
generating, by one or more processors, a first command signal commanding deflection of a two-axis pointing device kinematically coupled to the two-axis gimbal and positioned in the optical path of the line of sight, the first command signal based upon the measured acceleration of the moveable platform and an acceleration rate command representative of a relative target motion with respect to the azimuth gimbal;
measuring, in the line of sight inertial frame, the deflection of the two-axis pointing device responsive to the first command signal; and
generating, by the one or more processors, a second command signal commanding deflection of the azimuth gimbal based upon the deflection of the two-axis pointing device and the measured acceleration of the azimuth gimbal.
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Accused Products
Abstract
Control systems and methods are provided for improved azimuthal pointing control near gimbal zenith/nadir in two-axis gimbal systems mounted to moveable platforms. The system includes a two-axis gimbal and a two-axis pointing device mounted to the two-axis gimbal. The two-axis pointing device directs a line of sight axis based upon a commanded steering direction and movement of the platform in the inertial frame of the line of sight. The two-axis gimbal follows the movement of the two-axis pointing device, keeping the two-axis pointing device from encountering its mechanical limits. In this manner, inertial pointing control is maintained in the near gimbal zenith/nadir regime.
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Citations
16 Claims
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1. A method of azimuthal pointing of a line of sight (LOS), comprising:
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measuring, at a two-axis gimbal having an azimuth gimbal, an elevation gimbal, and a line of sight and kinematically coupled to a moveable platform; an acceleration of the moveable platform in an inertial frame of the line of sight, due to a motion of the moveable platform; and an acceleration of the azimuth gimbal relative to the platform, due to the motion of the moveable platform; generating, by one or more processors, a first command signal commanding deflection of a two-axis pointing device kinematically coupled to the two-axis gimbal and positioned in the optical path of the line of sight, the first command signal based upon the measured acceleration of the moveable platform and an acceleration rate command representative of a relative target motion with respect to the azimuth gimbal; measuring, in the line of sight inertial frame, the deflection of the two-axis pointing device responsive to the first command signal; and generating, by the one or more processors, a second command signal commanding deflection of the azimuth gimbal based upon the deflection of the two-axis pointing device and the measured acceleration of the azimuth gimbal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An azimuthal pointing system, comprising:
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a two-axis gimbal kinematically coupled to a moveable platform, the two-axis gimbal further including an elevation gimbal, an azimuth gimbal, and a line of sight; a two-axis pointing system kinematically coupled to the two-axis gimbal and inserted within the optical path of the line of sight; a first sensor adapted to measure the angle and rate of the azimuth gimbal relative to the moveable platform; a second sensor adapted to measure inertial motion of the line of sight; one or more processors adapted to generate; a first command signal commanding deflection of the two-axis pointing device, the first command signal based upon; a measurement, by the second sensor, of an acceleration of the moveable platform in an inertial frame of the line of sight, due to a motion of the moveable platform; and an acceleration rate command representative of a relative target motion with respect to the azimuth gimbal; and a second command signal for commanding deflection of the azimuth gimbal, the second command signal based upon; the deflection of the two-axis pointing device responsive to the first command signal; and a measurement, by the first sensor, of an acceleration of the azimuth gimbal with respect to the moveable platform, due to the motion of the moveable platform. - View Dependent Claims (9, 10, 11)
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12. A non-transitory computer-readable medium having computer-readable program codes embedded thereon for comparing decision options, the computer-readable program codes including instructions that, when executed by a processor, cause the processor to:
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measure, at a two-axis gimbal having an azimuth gimbal, an elevation gimbal, and a line of sight and kinematically coupled to a moveable platform; an acceleration of the moveable platform, in an inertial frame of the line of sight, due to a motion of the moveable platform; and an acceleration of the azimuth gimbal, relative to the platform, due to the motion of the moveable platform; generate a first command signal commanding deflection of a two-axis pointing device kinematically coupled to the two-axis gimbal and positioned within the optical path of the line of sight, the first command signal based upon the measured acceleration of the moveable platform and a relative target motion with respect to the azimuth gimbal; measure, in the line of sight inertial frame, the deflection of the two-axis pointing device responsive to the first command signal; and generate a second command signal commanding deflection of the azimuth gimbal based upon the deflection of the two-axis pointing device and the measured acceleration of the azimuth gimbal. - View Dependent Claims (13, 14, 15, 16)
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Specification