Angular Velocity Sensor Gain Error Correction
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Solution Overview
Problem
Conventional vehicular present position detection systems using angular velocity sensors face inaccuracies due to gain errors, particularly when differentiating between left and right turns, leading to degraded navigation accuracy.
Innovation Solution
A vehicular present position detection apparatus that employs a Kalman filter to estimate gain errors independently for left and right turns, adjusting gain correction amounts based on the estimated errors to improve navigation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same gain characteristics are used for left and right turns, then the system complexity is reduced, but the measurement precision of angular velocity sensor degrades
Solution Approach 1:
The patent segments the gain correction process by maintaining separate gain correction amounts for left turns and right turns. The correction amount adjustment portion selects and applies different correction amounts based on the determined turn direction, thereby addressing the asymmetry in angular velocity sensor characteristics without requiring a complete separate estimation system for each direction.
Solution Approach 2:
The patent applies local quality by using direction-specific gain correction amounts tailored to the actual performance characteristics of the angular velocity sensor in each turn direction. Instead of a uniform correction approach, the system adapts the correction locally based on whether the vehicle is turning left or right, improving measurement precision for each specific condition.
2Measurement precision
If independent gain error estimation for left and right turns is implemented, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the gain error estimation and correction process by maintaining separate gain correction amounts for left and right turns within the Kalman filter framework. This segmentation allows the system to address directional asymmetry while managing complexity through structured separation of correction parameters.
Solution Approach 2:
The patent changes the parameters of the Kalman filter by introducing direction-specific gain correction amounts as separate state variables. This parameter change enables the system to model and correct for asymmetric sensor characteristics while maintaining the mathematical framework of the Kalman filter, balancing precision improvement with computational manageability.
Data Source
AI summary
There is a need for improving the accuracy of estimating a gain error for an angular velocity sensor. An error estimation section and a correction section are provided as well as a gyroscope that detects an angular velocity of a vehicle. The error estimation section assumes the gain error of the gyroscope to be a state quantity and finds an estimated value for the gain error using a Kalman filter. Based on the gain error found by the error estimation section, the correction section corrects a gain correction amount used for gain correction of values detected by the gyroscope. The correction section corrects the gain correction amount dedicated to right turn based on the gain error found by the error estimation section when the vehicle is assumed to turn right. The correction section corrects the gain correction amount dedicated to left turn based on the gain error found by the error estimation section when the vehicle is assumed to turn left.