Vehicle Navigation Calibration Using Composite Accelerations
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Solution Overview
Problem
Modern vehicle navigation systems face accuracy issues due to dynamic errors caused by vehicle maneuvers and non-horizontal surfaces, which affect inertial motion sensors and wheel speed sensors, leading to misalignment and errors in Dead Reckoning positioning.
Innovation Solution
A method and apparatus for calibrating dynamic parameters using composite accelerations measured by an accelerometer, which aligns inertial navigation sensors with an Earth-fixed coordinate system and corrects distance and turn angle errors in wheel speed sensors data, improving navigation accuracy by compensating for tire radius changes and vehicle body rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Dead Reckoning positioning uses inertial motion sensors and wheel speed sensors to bridge GPS gaps, then navigation robustness is improved, but measurement precision deteriorates due to dynamic errors from vehicle maneuvers and non-horizontal surfaces
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the calibration parameters of inertial sensors and wheel speed sensors based on measured composite accelerations. The system changes the operational parameters (sensor alignment angles, tire radius values) in response to varying vehicle dynamics conditions, thereby maintaining positioning accuracy across different maneuvering states and road surfaces while preserving the robustness of DR positioning.
2Adaptability or versatility
If the vehicle suspension rolls or tilts during maneuvers or on banked roads, then vehicle dynamics adaptability is improved, but inertial sensor misalignment increases causing navigation errors
Solution Approach 1:
The patent implements feedback by continuously measuring composite accelerations from inertial sensors and using this information to update calibration parameters in real-time. The system creates a closed-loop control where sensor measurements feed back into the calibration process, allowing the navigation system to compensate for suspension-induced misalignments and maintain accuracy despite vehicle body rotations during maneuvers or on banked roads.
3Adaptability or versatility
If tire radius changes occur due to suspension compression or tire deformation, then vehicle maneuvering capability is improved, but wheel speed sensor accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calibrating tire radius parameters under various suspension compression conditions and storing these as lookup tables or calibration curves. Before actual navigation, the system establishes the relationship between composite acceleration patterns and corresponding tire radius changes, enabling it to quickly compensate for radius variations during maneuvers without real-time calculation delays.
4Measurement precision
If composite acceleration calibration is applied to correct sensor errors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a calibration system that simultaneously corrects multiple sensor types (inertial sensors and wheel speed sensors) using a unified approach based on composite acceleration measurements. The same calibration framework and processing algorithms are used across different sensor modalities, reducing overall system complexity despite the multi-functional calibration requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of vehicle navigation systems by effectively mitigating dynamic errors, improving distance and turn angle calculations, and enhancing flat tire detection sensitivity through precise calibration and compensation of sensor data.
Implementation Method 1
measuring composite accelerations of the vehicle
Data Source
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Figure 5~6B
AI summary
Apparatus and methods for calibrating dynamic parameters of a vehicle navigation system are presented. One method may include determining whether reference position data of a vehicle is available, and measuring composite accelerations of the vehicle. The method may further include generating distance and turn angle data based upon a wheel speed sensors data, computing distance and turn angle errors based upon the independent position data, and associating the distance and turn angle errors with composite accelerations. A second method presented includes calibrating an inertial navigation sensor within a vehicle navigation system. The second method may include determining reference position data and Inertial Navigation System (INS) data, aligning an IMU with the vehicle, and aligning the IMU with an Earth fixed coordinate system. The second method may further include computing the vehicle alignment with respect to a horizontal plane, and determining calibration parameters for distance sensors associated with the vehicle.