Missile navigation method
First Claim
1. A method of navigating a missile, the method comprising:
- using a microelectromechanical systems (MEMS) inertial measurement unit (IMU) as a primary data source, to provide angular rate data to a navigation system of the missile, wherein the using is temporarily suspended during periods following shock events to the missile;
using at least a secondary data source to provide pseudo rate data to the navigation system during the periods following the shock events; and
providing either the angular rate data or the pseudo rate data to an autopilot of the navigation system that directs a control section of the missile, to alter a course of the missile.
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Abstract
A missile has a pair of systems to provide acceleration information during flight. The primary system is a microelectromechanical systems (MEMS) inertial measurement unit (IMU) that provides accurate rate sensor output, such as providing pitch and yaw rates, at low cost, over a wide range of conditions. However MEMS IMUs are susceptible to temporary incorrect responses when subjected to shocks, such as acoustic-range shocks, for instance in the range of 10-20 kHz. The missile includes a secondary system to temporarily provide acceleration data during the periods following shocks, when the MEMS IMU does not provide valid (reliable or usable) rate sensor output, for use in estimating pseudo pitch and yaw rates. The secondary system may be an accelerometer that does not provide navigation-quality acceleration data, but does provide a sufficiently accurate response in order to maintain stable flight during the post-shock period.
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Citations
16 Claims
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1. A method of navigating a missile, the method comprising:
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using a microelectromechanical systems (MEMS) inertial measurement unit (IMU) as a primary data source, to provide angular rate data to a navigation system of the missile, wherein the using is temporarily suspended during periods following shock events to the missile; using at least a secondary data source to provide pseudo rate data to the navigation system during the periods following the shock events; and providing either the angular rate data or the pseudo rate data to an autopilot of the navigation system that directs a control section of the missile, to alter a course of the missile. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A missile navigation system comprising:
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a microelectromechanical systems (MEMS) inertial measurement unit (IMU); a secondary data source; IMU validity logic; a rate estimator; and an autopilot; wherein the secondary data source is operatively coupled to the rate estimator to provide data to the rate estimator to allow the rate estimator to produce pseudo angle rate changes in yaw and pitch directions; wherein the MEMS IMU and the rate estimator are coupled to the validity logic, which is in turn operatively coupled to the autopilot; and wherein the validity logic determines validity of data from the MEMS and IMU, and supplies to the autopilot either angle rate change data from the MEMS IMU or the pseudo angle rate changes produced by the rate estimator. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification