WGS-to-Cartesian Path Conversion Across Driving Zone Boundaries
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Solution Overview
Problem
Current methods for converting World Geodetic System (WGS) coordinates to cartesian coordinates for semi-autonomous or autonomous driving are inaccurate, computationally intensive, and face issues near zone boundaries, leading to discontinuities and precision problems across long distances and varying latitudes.
Innovation Solution
A method using a modified Bowring conversion with pre-calculated constants for each lane-group segment (LGS) to calculate global cartesian path coordinates, allowing accurate conversion and navigation across large distances and boundaries without excessive computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UTM conversion is used to project WGS coordinates to cartesian coordinates, then the conversion can be performed, but it becomes computationally cumbersome and causes accuracy problems near zone boundaries
Solution Approach 1:
The patent divides the path into multiple lane-group segments (LGSs), each with its own origin and pre-calculated constants. This segmentation allows the conversion to be performed locally for each segment rather than globally, reducing computational complexity while maintaining accuracy across zone boundaries.
Solution Approach 2:
The patent pre-calculates constants (including second and third-order terms) for each LGS origin before the vehicle reaches that segment. This preliminary action eliminates the need for complex real-time calculations during navigation, reducing computational burden while maintaining precision.
2Device complexity
If Bowring conversion is used to reduce computational complexity, then the conversion becomes less cumbersome, but it requires second and third-order terms to address northings at different latitudes and begins to have problems over longer distances
Solution Approach 1:
The patent applies local quality by pre-calculating specific constants (including second and third-order terms) for each LGS origin based on its latitude. This allows the simplified Bowring conversion to maintain accuracy at different latitudes without requiring complex global calculations, as each segment has its own locally-optimized constants.
Solution Approach 2:
By dividing the path into multiple LGSs with各自的 pre-calculated constants, the patent enables the use of simplified Bowring conversion locally while maintaining overall accuracy across long distances. Each segment's local constants compensate for latitude variations without requiring complex global transformations.
3Device complexity
If standard Bowring method is used without pre-calculated constants, then the conversion is simpler, but it cannot maintain precision over long distances and across varying latitudes
Solution Approach 1:
The patent pre-calculates constants including second and third-order terms for each LGS origin before navigation. This preliminary preparation maintains the simplicity of the Bowring conversion method during real-time operation while ensuring accuracy over long distances and varying latitudes through the pre-computed correction terms.
Data Source
AI summary
Methods and systems are described that enable world geodetic system (WGS) to cartesian coordinate conversion for driving. A path of a vehicle comprising lane-group segments (LGSs) is received. The LGSs comprise respective origins in WGS coordinates, respective path points in WGS coordinates; and respective groups of constants. For a first of the LGSs, global cartesian path coordinates are calculated, based on modified Bowring techniques, for the path points of the first LGS. The coordinates are calculated using the constants of the first LGS and respective differences between the path points of the first LGS and an origin of the first LGS. The vehicle can navigate along the path using the global cartesian path coordinates calculated for the first LGS. By using modified Bowring techniques and pre-calculated constants for each LGS of the path, accuracy can be maintained over long distances and across boundaries without requiring substantial computational overhead.