Fault-tolerant system, apparatus and method
First Claim
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1. A method for maintaining estimation integrity of a recursive stochastic filter comprising the steps of:
- measuring the output of a measurement device determining a fault-free residual from a residual process by operating on an updated recursive stochastic filter state estimation residual with a projection model;
determining a first probabilistic estimate of a fault from;
at least one projected recursive stochastic filter state estimation residual;
at least one measurement model, and at least one hypothesized first fault model, wherein the determining of a first probabilistic estimate of a fault is based on at least one of;
a Multiple Hypothesis Wald Sequential Probability Ratio Test; and
a Multiple Hypothesis Shiryayev Sequential Probability Ratio test;
testing for a fault based on the determined probabilistic estimate of a fault; and
outputting at least one probabilistic estimate of a fault
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Abstract
A method, apparatus and system are described having a minimum variance estimator of state estimates typically in navigation embodiments where a sensor and/or effecter fault detecting module is adapted to execute residual testing steps using the Multiple Hypothesis Wald Sequential Probability Ratio test, the Multiple Hypothesis Shiryayev Sequential Probability Ratio test, the Chi-Square test and combinations thereof to determine the likelihood of sensor and/or actuator fault occurrences and thereafter isolate the effects of the one or more identified fault from the state estimates.
210 Citations
54 Claims
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1. A method for maintaining estimation integrity of a recursive stochastic filter comprising the steps of:
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measuring the output of a measurement device determining a fault-free residual from a residual process by operating on an updated recursive stochastic filter state estimation residual with a projection model;
determining a first probabilistic estimate of a fault from;
at least one projected recursive stochastic filter state estimation residual;
at least one measurement model, and at least one hypothesized first fault model, wherein the determining of a first probabilistic estimate of a fault is based on at least one of;
a Multiple Hypothesis Wald Sequential Probability Ratio Test; and
a Multiple Hypothesis Shiryayev Sequential Probability Ratio test;
testing for a fault based on the determined probabilistic estimate of a fault; and
outputting at least one probabilistic estimate of a fault - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus comprising:
at least one measurement device operabley coupled with an at least one processor adapted to receive an output of the measurement device;
the at least one processor further adapted to;
determine a fault-free residual from a residual process by operating on an updated recursive stochastic filter state estimation residual with a projection model;
determine a first probabilistic estimate of a fault from;
at least one projected recursive stochastic filter state estimation residual;
at least one measurement model; and
at least one hypothesized first fault model, wherein the determining of a first probabilistic estimate of a fault is based on at least one of;
a Multiple Hypothesis Wald Sequential Probability Ratio Test;
a Multiple Hypothesis Shiryayev Sequential Probability Ratio test; and
a Chi-Square Test;
test for a fault based on the determined probabilistic estimate of a fault; and
output at least one probabilistic estimate of a fault. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A system for performing fault tolerant navigation comprising:
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a first global positioning satellite (GPS) receiver providing at least one position outputs and at least one time output;
an acceleration-determining device sensitive in at least three axes capable of providing acceleration measurements in at least three axes;
an angular rate measuring device sensitive in at least three axes capable of providing angular rates of rotation in at least three axes; and
at least one processor adapted to support a dynamic system model of the error propagation of the integrated acceleration determining devices and angular rate measuring devices and a hypothesized fault model for any or all of the acceleration determining devices and angular rate measuring devices;
the at least one processor further adapted to;
determine a fault-free residual from a residual process by operating on an updated recursive stochastic filter state estimation residual with a projection model;
determine a first probabilistic estimate of a fault from;
at least one projected recursive stochastic filter state estimation residual;
at least one measurement model, and at least one hypothesized first fault model, wherein the determining of a first probabilistic estimate of a fault is based on at least one of;
a Multiple Hypothesis Wald Sequential Probability Ratio Test; and
a Multiple Hypothesis Shiryayev Sequential Probability Ratio test;
testing for a fault based on the determined probabilistic estimate of a fault; and
outputting at least one of;
at least one probabilistic estimate of a fault and at least one fault free estimate.
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47. A system for performing fault tolerant navigation of a plurality of vehicles comprising:
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at least one primary vehicle;
at least one secondary vehicle;
a transmitter for transmitting the derived secondary vehicle fault free state estimate solutions; and
a receiver for receiving the transmitted derived fault free state estimate solution and measurements; and
at least one processor for deriving a primary-relative fault free state estimate solution for the secondary vehicle wherein the processor receiving at least one of;
a plurality of measurements of the one or more vehicle sensors, state estimators, or actuators and a plurality of commands transmitted to the one or more vehicle actuators;
and in a recursive stochastic filter having a vehicle-specific dynamic system model as a function of the one or more vehicle actuators;
determining a fault-free residual from a residual process by operating on an updated recursive stochastic filter state estimation residual with a projection model;
determining a first probabilistic estimate of a fault from;
at least one projected recursive stochastic filter state estimation residual;
at least one measurement model, and at least one hypothesized first fault model, wherein the determining of a first probabilistic estimate of a fault is based on at least one of;
a Multiple Hypothesis Wald Sequential Probability Ratio Test; and
a Multiple Hypothesis Shiryayev Sequential Probability Ratio test;
testing for a fault based on the determined probabilistic estimate of a fault;
estimating a fault direction model; and
outputting a fault-free state estimate. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54)
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Specification