Inertial Measurement Apparatus Scale Factor Error Correction
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Solution Overview
Problem
Inertial instruments, such as gyroscopes, face challenges in real-time error detection and correction of scale factor errors while maintaining continuous operation, particularly when scale factors from multiple instruments disagree, affecting the accuracy of measurements.
Innovation Solution
The implementation of first and second inertial instruments with parallel sense axes, using respective scale factors to generate corrected output signals by calculating differences in scale factors over time intervals where the sign of one scale factor changes, and employing a microprocessing unit with a Kalman Filter to compute and correct bias errors and scale factor imbalances, ensuring continuous operation and accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time error correction is implemented for inertial instruments, then measurement accuracy is improved, but device complexity increases due to the need for multiple instruments and computational processing
Solution Approach 1:
The system divides the measurement task into multiple parallel inertial instruments (at least two gyroscopes or accelerometers) that independently measure the same physical quantity. Each instrument operates separately with its own scale factor, and their results are combined through computational processing to achieve error correction. This segmentation allows the system to exploit differences in error characteristics between instruments to eliminate systematic errors.
Solution Approach 2:
The system implements a feedback mechanism where the outputs from multiple inertial instruments are continuously monitored and processed. The computational algorithm compares the measurements from different instruments, identifies scale factor discrepancies, and dynamically adjusts the corrected output signals in real-time. This closed-loop feedback enables continuous error correction without interrupting instrument operation.
2Reliability
If multiple inertial instruments are used with different scale factors, then error detection capability is improved, but the difficulty of detecting and measuring errors increases due to scale factor disagreements
Solution Approach 1:
The system introduces a computational algorithm as an intermediary that processes the raw outputs from multiple inertial instruments. This intermediary layer performs scale factor normalization by comparing measurements from different instruments and applying correction factors. The algorithm acts as a mediator that reconciles scale factor disagreements between instruments, transforming disparate measurements into a unified corrected output without requiring direct physical modification of the instruments.
3Productivity
If continuous operation of inertial instruments is maintained, then productivity is improved, but the ability to correct errors in real-time worsens due to the need for sign changes in scale factors
Solution Approach 1:
The system employs periodic sign reversals of scale factors at predetermined intervals during continuous operation. This periodic action allows the computational algorithm to systematically vary the scale factor signs, creating distinguishable measurement patterns that enable error detection and correction. The periodic sign changes are integrated into the continuous measurement process, allowing error correction to occur without interrupting the overall operation of the inertial instruments.
Data Source
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AI summary
An exemplary inertial measurement apparatus has first and second inertial instruments that are oriented to have parallel sense axes and that produce respective first and second sensed output signals representative of an inertial attribute to be measured. Respective first and second scale factors are used in producing the first and second sensed output signals. Bias errors in the first and second instruments are estimated using the change in state of sign of the first and second scale factors during the first and succeeding time intervals. To facilitate measurement of bias errors in the first and second instruments, a substitute scale factor is determined to be an equivalent of the second scale factor and is based on the first scale factor and a difference between the first and second scale factors. Errors in the second scale factor are calculated based on the first scale factor and the substitute scale factor during first and succeeding time intervals where a sign of one of first and second scale factors changes from one state during the first time interval to the other state during the succeeding time intervals. First and second corrected output signals are generated based on the respective first and second sensed output signals and correction of said second scale factor error.