Vibration compensation for sensors
First Claim
1. A method of reducing the effect of vibration-induced errors in a sensor (124), the method comprising:
- receiving from a calibration procedure a set of calibration sensitivity coefficients relating vibration power levels at various frequencies to errors of the particular sensor (124);
obtaining high data rate vibration samples from a further sensor (126);
estimating vibration power spectral density (130); and
combining the estimates with the calibration coefficients to generate real time vibration-induced error correction (134) for the sensor (124).
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Abstract
Vibration induced errors in sensors are predicted based on a measurement of vibration power spectra. Accelerometer samples are used to estimate vibration power spectral densities. A calibration procedure using suitable vibration stimulus provides the ability to estimate sensitivity coefficients to be used to compensate for the vibration induced error. The vibration power spectrum estimates are combined with previously obtained calibration coefficients to generate real time vibration-induced error corrections. Vibration bias sensitivity coefficients are estimated in a controlled environment to ensure their accuracy to compensate the sensor in real-time applications using acceleration measurement devices such as accelerometers mounted to a rigid sensor assembly shared with the sensor to be compensated. Vibration bias estimates are then used to correct the outputs of the sensors(s) being compensated for vibration-induced error.
64 Citations
30 Claims
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1. A method of reducing the effect of vibration-induced errors in a sensor (124), the method comprising:
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receiving from a calibration procedure a set of calibration sensitivity coefficients relating vibration power levels at various frequencies to errors of the particular sensor (124);
obtaining high data rate vibration samples from a further sensor (126);
estimating vibration power spectral density (130); and
combining the estimates with the calibration coefficients to generate real time vibration-induced error correction (134) for the sensor (124). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer implemented method of compensating for vibration induced error in sensors, the method comprising:
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receiving from a calibration procedure a set of sensitivity coefficients relating vibration power levels at various frequencies to a bias-like error of a particular sensor;
buffering vibration samples from a further sensor in at least one axis of vibration;
computing a power spectral density for such buffered vibration samples;
computing vibration power values in multiple frequency bins;
combining the vibration power values with the sensitivity coefficients to obtain estimated vibration induced errors. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of calculating correction coefficients for a particular inertial sensor comprising:
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for each j of a plurality of M test conditions having N<
M different dominant vibration frequencies,subjecting the sensor to a reference acceleration corresponding to the jth test condition;
measuring acceleration of the sensor from the sensor output;
computing vibration power in selected frequency bins corresponding to the measured acceleration;
providing a difference in measured acceleration from a reference acceleration;
combining the measured acceleration and the difference to obtain vibration sensitivity coefficients for the jth test condition.
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21. A system that provides vibration calibration coefficients for a sensor affected by vibration, the system comprising:
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means for receiving measured acceleration from an output of the sensor for a plurality of test conditions having different dominant vibration frequencies;
means for computing vibration power resulting from each of the test conditions in selected frequency bins;
means for providing a difference in measured acceleration from a reference acceleration corresponding to each of the test conditions; and
means for combining the measured acceleration and the difference from each of the test conditions to obtain vibration sensitivity coefficients for all of the frequency bins. - View Dependent Claims (22, 24, 25, 26, 27, 28, 29)
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23. A system for compensating for vibration induced sensor (120) error, the system comprising:
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an accelerometer (126);
an estimator (130) coupled to the accelerometer (126) for producing a power spectral density;
a compensation module (134) for combining the power spectral density and a plurality of calibration sensitivity coefficients (140) relating vibration power levels at various frequencies to a bias-like error of a particular sensor to provide a compensation value for the sensor output.
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30. A system for compensating for vibration induced error in a sensor, the system comprising:
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means holding a set of sensitivity coefficients relating vibration power levels at various frequencies to a bias-like error associated with the particular sensor;
means for buffering vibration samples in at least one axis of vibration;
means for computing a power spectral density for such buffered vibration samples;
means for computing vibration power values in multiple frequency bins;
means for combining the vibration power values with the sensitivity coefficients to obtain estimated vibration induced errors for the sensor.
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Specification