Vehicle Location Accuracy Using Compass and Stability Control
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Solution Overview
Problem
Vehicle navigation systems face challenges in accurately determining location in areas with poor GPS signal conditions, such as high-density urban areas or parking garages, where satellite-based positioning systems fail to provide reliable data.
Innovation Solution
A system that utilizes a combination of satellite-positioning data, compass data, and stability control data to estimate the vehicle's location, including the use of a controller to maintain a last-known location and correct compass readings based on forward acceleration and grade information from stability control data, and employs multiple non-satellite-based positioning methods to compute an overall current location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite-based positioning is used for vehicle location determination, then location accuracy is improved in open areas, but location reliability deteriorates in high-density urban areas or parking garages where GPS signals are unavailable
Solution Approach 1:
The patent combines multiple positioning approaches (GPS satellite-based positioning, compass heading, and stability control data from accelerometers) into a unified location determination system. The controller integrates these different data sources to estimate vehicle location, ensuring continuous navigation capability whether GPS signals are available or not.
Solution Approach 2:
The patent introduces intermediate calculation steps where the controller uses stability control data (accelerometer readings) as a mediator to correct compass heading measurements. This intermediate correction process accounts for vehicle acceleration and deceleration effects on the magnetic compass, improving the accuracy of dead reckoning when GPS is unavailable.
2Reliability
If multiple sensor inputs are integrated for location estimation, then location reliability is improved in poor GPS conditions, but device complexity increases
Solution Approach 1:
The patent makes existing vehicle components serve multiple functions. The stability control system, originally designed for safety purposes, is also used for location estimation. The compass serves both traditional navigation purposes and provides heading information for dead reckoning. This multi-functionality approach increases reliability without requiring entirely new dedicated components.
Solution Approach 2:
The vehicle's existing stability control sensors (accelerometers) serve the additional function of correcting compass readings and providing data for dead reckoning calculations. The system uses resources already present in the vehicle, reducing the need for additional dedicated hardware and minimizing overall system complexity.
3Reliability
If compass data is used for location estimation during GPS outages, then location continuity is improved, but measurement precision deteriorates due to acceleration and grade effects on compass accuracy
Solution Approach 1:
The patent implements a feedback mechanism where stability control data (accelerometer readings) continuously monitors vehicle motion and provides correction information to the compass heading measurements. The controller uses this feedback to compensate for acceleration and deceleration effects on the magnetic compass, maintaining measurement precision while ensuring location continuity during GPS outages.
Solution Approach 2:
The patent dynamically adjusts the interpretation of compass data based on vehicle motion parameters obtained from stability control sensors. When acceleration or deceleration is detected, the system modifies how compass readings are processed and corrected. This parameter-based adjustment maintains compass accuracy under varying vehicle conditions while ensuring continuous location tracking.
Data Source
AI summary
A controller may maintain a last-known vehicle location, and, when satellite-positioning data is unavailable from a satellite-based positioning-system module, utilize compass data and stability control data to estimate a current vehicle location from the last-known vehicle location. The controller may avoid use of the compass data to estimate the current vehicle location when the vehicle is accelerating or decelerating in East or West headings.