Fault tolerant inertial reference system
First Claim
1. A fault tolerant inertial reference system comprising:
- a first inertial reference unit including,a first array of at least four inertial sensors mounted along skewed axes to a support frame for providing a first array of inertial sensor outputs,a first satellite positioning system position estimator for obtaining first positional information related to said support frame,means for determining first low-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, said first positional information, and first fault-free inertial sensor configuration information,means for determining first high-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, a second array of inertial sensor outputs from a second array of at least four inertial sensors mounted along skewed axes to said support frame, independent of said first array of inertial sensors, and said first fault-free inertial sensor configuration information,first fault isolation and reconfiguration means, responsive to said first low-speed error estimates and said first high-speed error estimates, for determining said first fault-free inertial sensor configuration information indicative of any faulty inertial sensors of said first inertial sensor array, andfirst inertial reference processor responsive to said first fault-free inertial sensor configuration and said first array of inertial sensor outputs for providing first fault tolerant inertial reference information derived from those ones of said first array of inertial sensor being fault-free; and
a second inertial reference unit including,said second array of inertial sensors for providing said second array of inertial sensor outputs,a second satellite positioning system position estimator for obtaining second positional information related to said support frame,means for determining second low-speed inertial sensor error estimates as a function of said second array of inertial sensor outputs, said second positional information obtained from said second satellite positioning system position estimator, and second fault-free inertial sensor configuration information,means for determining second high-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, said second array of inertial sensor outputs, and said second fault-free inertial sensor configuration information,second fault isolation and reconfiguration means, responsive to said second low-speed error estimates and said second high-speed error estimates, for determining said second fault-free inertial sensor configuration information indicative of any faulty inertial sensors of said second inertial sensor array, andsecond inertial reference processor responsive to said second fault-free inertial sensor configuration and said second array of inertial sensor outputs for providing second fault tolerant inertial reference information derived from those ones of said second array of inertial sensors being fault-free.
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Abstract
A fault tolerant inertial reference system employs two independent inertial reference units each having its own inertial sensor array with redundant output information. Each inertial reference unit includes an independent source of position and velocity information through employment of a satellite positioning system. In turn, a high-speed error estimator processes inertial sensor output data from a local inertial sensor array with inertial sensor output data from another external inertial sensor array for determining high-level errors, and a low-speed error estimator processes output data from the local inertial sensor array with the velocity and position information separately obtained from the satellite positioning system for determining low-level errors. In turn these high and low-level errors are processed to determine a fault-free inertial sensor configuration for subsequently determining reliable fault tolerant inertial reference data obtainable with a minimum set of inertial sensors.
32 Citations
10 Claims
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1. A fault tolerant inertial reference system comprising:
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a first inertial reference unit including, a first array of at least four inertial sensors mounted along skewed axes to a support frame for providing a first array of inertial sensor outputs, a first satellite positioning system position estimator for obtaining first positional information related to said support frame, means for determining first low-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, said first positional information, and first fault-free inertial sensor configuration information, means for determining first high-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, a second array of inertial sensor outputs from a second array of at least four inertial sensors mounted along skewed axes to said support frame, independent of said first array of inertial sensors, and said first fault-free inertial sensor configuration information, first fault isolation and reconfiguration means, responsive to said first low-speed error estimates and said first high-speed error estimates, for determining said first fault-free inertial sensor configuration information indicative of any faulty inertial sensors of said first inertial sensor array, and first inertial reference processor responsive to said first fault-free inertial sensor configuration and said first array of inertial sensor outputs for providing first fault tolerant inertial reference information derived from those ones of said first array of inertial sensor being fault-free; and a second inertial reference unit including, said second array of inertial sensors for providing said second array of inertial sensor outputs, a second satellite positioning system position estimator for obtaining second positional information related to said support frame, means for determining second low-speed inertial sensor error estimates as a function of said second array of inertial sensor outputs, said second positional information obtained from said second satellite positioning system position estimator, and second fault-free inertial sensor configuration information, means for determining second high-speed inertial sensor error estimates as a function of said first array of inertial sensor outputs, said second array of inertial sensor outputs, and said second fault-free inertial sensor configuration information, second fault isolation and reconfiguration means, responsive to said second low-speed error estimates and said second high-speed error estimates, for determining said second fault-free inertial sensor configuration information indicative of any faulty inertial sensors of said second inertial sensor array, and second inertial reference processor responsive to said second fault-free inertial sensor configuration and said second array of inertial sensor outputs for providing second fault tolerant inertial reference information derived from those ones of said second array of inertial sensors being fault-free. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification