Navigation system for spinning projectiles
First Claim
1. A sensor system for a spinning object in a magnetic field, to provide navigation information relative to a known frame of reference, the known frame of reference defined by a first known axis, a second known axis being perpendicular to the first known axis, and a third known axis being perpendicular to the first and second known axes, the spinning object having a despun frame of reference defined by a first despun axis aligned with the spin axis of the projectile, a second despun axis perpendicular to the first despun axis and the magnetic field, and a third despun axis perpendicular to the first despun axis and the second despun axis, the navigation system comprising:
- a signal processor;
at least one magnetic sensor in communication with the signal processor, the at least one magnetic sensor configured to provide a first electrical signal representative of the angular orientation of the body relative to the second despun axis and the third despun axis; and
at least one angular rate sensor in communication with the signal processor, the at least one angular rate sensor configured to provide a second electrical signal representative of the angular rate of rotation of the object relative to the known frame of reference,wherein the signal processor processes the first and second electrical signals to provide output signals representative of the instantaneous attitude of the spinning object relative to the known frame of reference.
1 Assignment
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Accused Products
Abstract
A navigation system for spinning projectiles using a magnetic spin sensor to measure the projectile roll angle by sensing changes in magnetic flux as the projectile rotates through the earth'"'"'s magnetic field is disclosed. The magnetic spin sensor measurements are used to despin a body reference frame such that position, velocity, and attitude of the projectile can be determined by using a strapdown inertial navigation system (INS) algorithm. More particularly, a multisensor concept is used to measure pitch and yaw angular rates, by measuring Coriolis acceleration along the roll axis and demodulating the pitch and yaw rates therefrom.
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Citations
22 Claims
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1. A sensor system for a spinning object in a magnetic field, to provide navigation information relative to a known frame of reference, the known frame of reference defined by a first known axis, a second known axis being perpendicular to the first known axis, and a third known axis being perpendicular to the first and second known axes, the spinning object having a despun frame of reference defined by a first despun axis aligned with the spin axis of the projectile, a second despun axis perpendicular to the first despun axis and the magnetic field, and a third despun axis perpendicular to the first despun axis and the second despun axis, the navigation system comprising:
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a signal processor; at least one magnetic sensor in communication with the signal processor, the at least one magnetic sensor configured to provide a first electrical signal representative of the angular orientation of the body relative to the second despun axis and the third despun axis; and at least one angular rate sensor in communication with the signal processor, the at least one angular rate sensor configured to provide a second electrical signal representative of the angular rate of rotation of the object relative to the known frame of reference, wherein the signal processor processes the first and second electrical signals to provide output signals representative of the instantaneous attitude of the spinning object relative to the known frame of reference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A navigation system for a spinning object in a magnetic field comprising:
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a signal processor; at least one magnetic sensor, attached to the spinning object and in communication with the signal processor, the at least one magnetic sensor configured to provide a roll signal representative of the orientation of the magnetic sensor relative to the magnetic field; a Coriolis acceleration sensor, attached to the spinning object and in communication with the signal processor, the Coriolis acceleration sensor configured to provide an attitude rate signal representative of the pitch rate and yaw rate of the object; at least one linear accelerometer, attached to the spinning object and in communication with the signal processor, the at least one linear accelerometer configured to provide an acceleration signal representative of the components of acceleration of the spinning object perpendicular to the roll axis; and a global positioning system (GPS) receiver, attached to the spinning object and in communication with the signal processor, the GPS receiver configured to provide a position signal representative of the position of the spinning object, wherein the signal processor is adapted to provide an output signal representative of the position, velocity, and attitude of the spinning object. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of determining the position, velocity, and attitude of a spinning projectile travelling through the magnetic field of the Earth, the method comprising:
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sensing the roll angle of the spinning projectile using a magnetic sensor; communicating the roll angle to an inertial navigation system; sensing the pitch rate and yaw rate of the spinning projectile using a Coriolis accelerometer; communicating the pitch rate and yaw rate to the inertial navigation system; sensing the acceleration of the spinning object; and communicating the acceleration of the spinning object to the inertial navigation system. - View Dependent Claims (19, 20, 21, 22)
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Specification