Laser gyro life prediction
First Claim
1. A lifetime predicting laser gyro apparatus comprising:
- (a) laser gyro means having at least one parameter of performance; and
(b) means for predicting when the laser gyro means will fail based on the at least one parameter of performance.
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Accused Products
Abstract
A laser gyro lifetime prediction method incorporates a memory model that stores a worst case performance parameter for a readout intensity, a laser intensity and a derived quantity known as volts per mode for a laser gyro. A microprocessor based life prediction method utilizes a predetermined failure criteria to judge a estimate of laser gyro life based on historic performance of laser gyro operating parameters. The prediction is based on a linear quadratic or higher order fit of lifetime data for critical temperatures. The performance data is stored in a memory model for each critical temperature and parameter. The laser gyro reports eminent failures to the inertial navigation system or a host controller. Routine scheduled maintenance of the laser gyro is enhanced by knowing its lifetime.
10 Citations
25 Claims
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1. A lifetime predicting laser gyro apparatus comprising:
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(a) laser gyro means having at least one parameter of performance; and (b) means for predicting when the laser gyro means will fail based on the at least one parameter of performance. - View Dependent Claims (2, 3, 4)
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5. A lifetime prediction apparatus for a laser gyro including a laser gyro block, a lasing means, at least one performance parameter and at least one predetermined failure limit, the lifetime prediction apparatus comprising:
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(a) a temperature measurement means for measuring a laser gyro temperature having a sensing input connected to the laser gyro block and having a block temperature output; (b) means for measuring volts per mode connected to the lasing means having a volts per mode performance parameter output; (c) performance processing means for determining a critical temperature having an input for receiving the block temperature output and the volts per mode performance parameter output, and having a performance parameter output and a performance data output; (d) a storage means connected to the performance parameter output; and (e) functional estimation means for calculating a gyro end of life based on a predetermined functional estimation, connected to the performance data output. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A lifetime prediction method for a laser gyro including at least one performance parameter and at least one predetermined failure limit comprising the steps of:
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(a) creating a memory model of the performance of a performance parameter constituting a three-dimensional array of temperature parameters and lifetime where the lifetime is measured over a predetermined range and within the range there is a predetermined number of bins having a top bin and a bottom bin wherein the predetermined number of bins exists for each temperature; (b) measuring the temperature of the laser gyro; (c) determining whether the temperature is a critical temperature and if it is a critical temperature executing the following steps; (d) accessing the performance parameter for the laser gyro; (e) determining whether the laser gyro is in the start up mode and if it is enabling the use of a volts per mode parameter; (f) calculating a bin number based on the current time; (g) determining if the bin is a new bin not already in the memory model and if it is shifting all elements of the bin down to a lower bin so that the oldest data is eliminated and the new data is put in the top bin; (h) accessing the bin at this time period for the last performance data; (i) comparing the last performance data to the current parameter and if it is greater than or equal to the currently stored parameter then not executing the next step; (j) replacing the parameter if it is less than the current parameter; (k) calculating a new end of life based on a predetermined fit of the life data in the memory model; (l) storing the life data in the life matrix at that time and temperature; (m) determining the life as being the estimated life minus the current time; (n) if the life is less than ten hours indicating an eminent failure; (o) if the life is between ten hours and 100 hours indicating a warning; and (p) if the life is between 100 hours and 1000 hours indicating a caution and indication of needed maintenance. - View Dependent Claims (22, 23, 24, 25)
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Specification