GNSS Signal Filtering Using Digital Map Projection for Urban Positioning
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Solution Overview
Problem
In urban areas, satellite signal occlusion due to high-rise buildings and narrow spaces leads to reduced position accuracy in electronic devices relying on GPS signals.
Innovation Solution
An electronic device employs filtering of GNSS signals to identify valid satellites, uses a digital map to project satellite positions and identify candidate satellites, and determines target satellites meeting line of sight criteria to minimize signal occlusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional GPS receivers are used in urban areas, then device complexity is low, but position accuracy deteriorates due to satellite signal occlusion from high-rise buildings and narrow spaces
Solution Approach 1:
The patent projects three-dimensional satellite positions and building structures onto two-dimensional planes along multiple directions (first direction and second direction orthogonal to the first). This dimensional transformation enables the system to analyze line-of-sight relationships by examining whether projection segments intersect with building boundaries in 2D space, effectively solving the 3D signal occlusion problem through 2D projection analysis
Solution Approach 2:
The patent divides the satellite identification process into multiple stages: obtaining candidate satellites from valid satellites, then identifying target satellites from candidate satellites. It also segments the analysis into orthogonal projection directions, examining line-of-sight relationships in different spatial dimensions to comprehensively determine satellite visibility
2Measurement precision
If additional sensors like 3D LiDAR or SkyView camera are used to address signal occlusion, then position accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent uses a digital map as a virtual copy of the physical environment, representing building positions, shapes, and heights in digital form. This digital replica enables the system to simulate and analyze line-of-sight relationships between satellites and the receiver without requiring physical sensors like LiDAR or cameras to scan the actual surroundings
Solution Approach 2:
The patent replaces physical sensing mechanisms (LiDAR, cameras) with computational geometry methods. Instead of using optical or electromagnetic sensors to detect building structures, the system uses mathematical projection and intersection analysis on digital map data to determine satellite visibility, substituting mechanical/optical systems with algorithmic processing
3Measurement precision
If multiple filtering stages are implemented to identify target satellites, then position accuracy improves, but processing time increases
Solution Approach 1:
The patent performs preliminary filtering to obtain candidate satellites from valid satellites before conducting the detailed line-of-sight analysis. This preliminary action reduces the number of satellites requiring computationally intensive projection and intersection analysis, thereby optimizing processing time while maintaining identification accuracy
Data Source
AI summary
An electronic device includes a memory storing computer-executable instructions and at least one processor that accesses the memory and executes the instructions. The at least one processor filters received global navigational satellite system (GNSS) signals to identify valid satellites, based on receiving the GNSS signals, obtains a digital map of a predetermined target area around a reference position, identifies candidate satellites from the valid satellites, based on coordinates obtained by projecting positions of the valid satellites and the reference position in a first direction and the digital map, in a 3D space including the positions of the valid satellites and the reference position, and identifies at least one target satellite meeting a line of sight (LOS) at the reference position, based on coordinates obtained by projecting positions of the candidate satellites and the reference position in a second direction and the digital map.