Inertial Sensor Offset Compensation Using Modified Moving Average
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Solution Overview
Problem
Inertial sensors in automotive vehicles face accuracy issues due to temperature variations, flicker noise, thermo-mechanical white noise, and bias instability, which are exacerbated by complex applications and long travel periods without frequent stops, making it challenging to ensure accurate measurements.
Innovation Solution
A method using a modified moving average (MMA) for dynamic offset compensation of inertial sensor outputs, applicable both when the vehicle is stopped and in motion, with a transition period for smooth compensation, and compatible with cost-effective processing and driving circuitry, allowing for continuous error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If static bias offset compensation is used when the vehicle is stopped, then the sensor accuracy is improved, but the compensation effectiveness deteriorates during lengthy travel when vehicles do not make frequent stops
Solution Approach 1:
The patent transitions from static bias offset compensation (performed only when vehicle is stopped) to dynamic bias offset compensation (performed continuously during vehicle operation). The system now updates bias offsets in real-time during motion, allowing the compensation to adapt to changing environmental conditions and sensor drift that occur during lengthy travel periods without stops.
2Measurement precision
If modified moving average is used for dynamic offset compensation during vehicle motion, then the measurement accuracy is improved during travel, but the processing complexity increases
Solution Approach 1:
The patent applies a modified moving average (MMA) algorithm that changes the processing parameters dynamically based on vehicle state. During motion, the system uses MMA with specific window sizes and update rates optimized for dynamic conditions, while during stops it uses different parameters. This parameter adaptation allows accurate compensation without requiring excessively complex processing throughout all operating conditions.
3Measurement precision
If frequent vehicle stops are made to update bias offset, then the compensation accuracy is improved, but the productivity and operational efficiency deteriorate
Solution Approach 1:
The patent implements continuous bias offset compensation during vehicle operation using the modified moving average algorithm. Instead of requiring the vehicle to stop periodically to update compensation parameters, the system continuously processes sensor data and updates bias offsets in real-time during motion. This eliminates the need to interrupt productive travel for calibration purposes.
4Ease of manufacture
If traditional filtering methods are used to correct sensor output, then the implementation is simple, but the ability to handle multiple error sources deteriorates
Solution Approach 1:
The modified moving average algorithm serves multiple functions simultaneously: it filters high-frequency noise, compensates for bias drift, adapts to changing environmental conditions, and provides robust performance across different vehicle operating states. This multi-functional approach replaces the need for multiple separate filtering stages while maintaining implementation simplicity through a unified algorithmic framework.
Data Source
AI summary
The present invention provides an improved method and system for compensation of inertial sensors. In one implementation a modified moving average is applied to provide dynamic offset compensation for an inertial sensor output that is calculated when a vehicle is in motion.