Compass Heading Display for Mobile Devices
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Solution Overview
Problem
Conventional mobile devices provide less reliable compass headings when in motion at higher speeds, such as in a car or train, due to rapid changes in the onboard compass orientation, leading to decreased accuracy.
Innovation Solution
A method and system that uses a combination of an onboard compass and a coordinate system receiver, like GPS, to determine the compass heading. The device checks if it is moving above a velocity threshold; if so, it calculates the heading using coordinates, otherwise, it displays the heading from the onboard compass. This ensures accurate compass display regardless of motion speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the onboard compass is used to determine compass heading, then the device can provide heading guidance when stationary, but the accuracy decreases when the device moves at higher speeds
Solution Approach 1:
The system dynamically switches between two different methods for determining compass heading based on the device's motion state. When the device is stationary or moving slowly, the onboard compass is used. When the device moves at higher speeds, the system switches to using coordinate data from the coordinate system receiver to calculate the heading based on the rate of change of coordinates, thereby adapting the method to the current operational conditions to maintain accuracy.
Solution Approach 2:
The system changes the parameter used for heading determination based on motion conditions. Instead of relying solely on the onboard compass magnetic field measurements, the system uses the rate of change of coordinates from the coordinate system receiver as an alternative parameter. This parameter change allows the system to maintain heading accuracy under varying motion speeds by selecting the appropriate measurement approach based on the current speed condition.
2Reliability
If the onboard compass is used for heading determination, then the system is simple, but the reliability deteriorates during rapid orientation changes
Solution Approach 1:
The system segments the operation into distinct modes: a first mode for when the device is stationary or moving slowly, using the onboard compass; and a second mode for when the device moves at higher speeds, using coordinate-based calculation. This segmentation allows each mode to use the most appropriate method for its conditions, improving overall reliability without requiring the complex system to be always active, thus managing complexity effectively.
Solution Approach 2:
The system introduces an intermediary approach by using the rate of change of coordinates from the coordinate system receiver as a mediator between the device's motion state and the heading determination. This intermediary parameter allows the system to transition smoothly between the simple onboard compass method and the more complex coordinate-based method, providing reliable heading information during motion without requiring immediate complex calculations.
3Measurement precision
If coordinate-based heading calculation is used, then accuracy is maintained during motion, but the system complexity increases
Solution Approach 1:
The system dynamically activates the coordinate-based heading calculation only when necessary, specifically when the device is detected to be moving at higher speeds. When the device is stationary or moving slowly, the system uses the simpler onboard compass method. This dynamic activation ensures measurement precision is maintained during motion conditions while avoiding unnecessary system complexity during stationary operation.
Solution Approach 2:
The system changes the measurement parameter based on motion conditions. Instead of continuously using complex coordinate-based calculations, the system switches to using the rate of change of coordinates as an alternative parameter when the device moves at higher speeds. This parameter change enables precise heading measurement during motion while keeping the overall system complexity manageable by using simpler methods when appropriate.
Data Source
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AI summary
A method for displaying a compass heading implemented by a computerized mobile device includes displaying a compass heading on a display of a computerized mobile device according to a compass onboard the computerized mobile device if the computerized mobile device is traveling below a motion threshold. The method also includes displaying a compass heading on a display of a computerized mobile device according to a compass heading calculated using at least two coordinates for the computerized mobile device if the computerized mobile device is traveling above the motion threshold.