GPS Positioning Excluding Low-Elevation Satellites
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Solution Overview
Problem
GPS positioning accuracy is compromised in environments with buildings due to multipath effects, especially when low-elevation-angle satellites are included in positioning calculations, leading to unreliable positioning results.
Innovation Solution
A method that searches for satellite signals, combines satellites to extract sets for positioning, performs first and second positioning calculations excluding low-elevation-angle satellites, and determines the appropriateness of the positioning result based on the difference between these calculations, using satellite signals from acquired satellites with specific elevation and signal quality conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of satellites used for positioning calculations is increased, then positioning accuracy is improved in open-sky environment, but positioning accuracy deteriorates when low-elevation-angle satellites are included due to multipath effects
Solution Approach 1:
The patent extracts and excludes low-elevation-angle satellites from the satellite set used for positioning calculations. By identifying satellites with elevation angles below a predetermined threshold and removing them from calculations, the system eliminates the source of multipath errors while retaining signals from higher-elevation satellites, thus resolving the contradiction between using more satellites and avoiding multipath-affected satellites
Solution Approach 2:
The patent applies different quality criteria to different satellites based on their elevation angles. Low-elevation-angle satellites are treated differently (excluded) from high-elevation-angle satellites (included), recognizing that not all satellites contribute equally to positioning accuracy. This local differentiation in satellite quality assessment resolves the contradiction by selectively utilizing satellites based on their individual characteristics
2Quantity of substance
If low-elevation-angle satellites are included in positioning calculations, then the number of available satellites increases, but the positioning result differs significantly from the actual position due to multipath
Solution Approach 1:
The patent extracts low-elevation-angle satellites from the complete satellite set and excludes them from positioning calculations. By setting a predetermined elevation angle threshold and removing satellites below this threshold, the system reduces the total number of satellites used but ensures that only high-quality, multipath-resistant satellites contribute to the positioning result, thereby maintaining accuracy
3Productivity
If positioning calculations are performed using all acquired satellites, then calculation efficiency is maintained, but positioning reliability decreases when multipath-affected satellites are included
Solution Approach 1:
The patent performs preliminary filtering of satellites by elevation angle before conducting positioning calculations. By pre-identifying and excluding low-elevation-angle satellites from the calculation set, the system ensures that only reliable satellites are used in the main positioning algorithm, maintaining both efficiency and reliability without requiring post-calculation verification or correction
Data Source
AI summary
A positioning method that performs current position calculations and outputs a positioning result position includes searching for satellite signals transmitted from positioning satellites to acquire satellites, combining satellites among the acquired satellites to extract satellite sets used for positioning, performing first positioning calculations on each calculation-target satellite set among the extracted satellite sets using the satellite signals transmitted from the acquired satellites included in the calculation-target satellite set, performing second positioning calculations on each calculation-target satellite set among the extracted satellite sets using the satellite signals transmitted from the acquired satellites that are included in the calculation-target satellite set, but do not include a low-elevation-angle satellite, and determining whether or not a positioning result obtained using the calculation-target satellite set is appropriate based on the difference between a position calculated by the first positioning calculations and a position calculated by the second positioning calculations, the elevation angle of the low-elevation-angle satellite satisfying a given low elevation angle condition, and determining the positioning result position from the positions calculated by the first positioning calculations on the satellite sets for which the positioning result has been determined to be appropriate.