Camera-Based GNSS Obstruction Detection for Urban Positioning
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Solution Overview
Problem
GNSS performance degrades in urban environments due to multipath errors caused by obstructions, leading to inaccurate positioning information, as current techniques for identifying and excluding multipath signals are not reliable.
Innovation Solution
A method that uses a camera on a mobile device to obtain images of obstructions, determines the obstructed portions of the sky based on orientation information, and identifies obstructed satellites to de-weight their signals in GNSS position determination, potentially sharing this information with other devices for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS signals are received in urban environments with obstructions, then positioning functionality is provided, but positioning accuracy degrades due to multipath errors from reflected signals
Solution Approach 1:
The system performs preliminary identification of obstructed satellites using camera images and orientation data before conducting GNSS position determination. By pre-determining which satellites are blocked by obstructions, the system can exclude their signals from processing, thereby preventing multipath errors from degrading positioning accuracy
Solution Approach 2:
The system extracts and excludes signals from obstructed satellites from the GNSS position determination process. By identifying which satellites are blocked and removing their signals from consideration, the system eliminates the harmful multipath effects while maintaining positioning functionality using only unobstructed satellite signals
2Reliability
If current techniques are used to identify multipath signals, then signal processing is simplified, but reliability of multipath signal exclusion is insufficient
Solution Approach 1:
The system introduces camera images and orientation information as intermediary data to identify obstructed satellites. Instead of directly analyzing GNSS signals for multipath characteristics, the system uses visual obstruction detection as a mediator to determine which satellite signals should be excluded, providing more reliable identification without excessively complicating the signal processing
Solution Approach 2:
The system replaces complex signal-based multipath detection methods with a visual obstruction detection approach using the camera. By substituting optical measurement (camera imaging) for radio frequency signal analysis, the system achieves more reliable obstruction identification while simplifying the overall processing architecture
Data Source
AI summary
Techniques for enhanced Global Navigation Satellite Systems (GNSS) position determination can include capturing an image, from a camera, of obstructions near a mobile device. Orientation information regarding the camera can is used to determine where, in the image, the horizon is situated, and which portions of the sky are blocked by the obstructions from the perspective of the mobile device. Information regarding the location of satellites in the sky is obtained, based on an estimated position of the mobile device. Obstructed satellites can then be identified by comparing the location of the satellites with the obstructed portions of the sky. In a GNSS position determination, information received from the obstructed satellites can then be disregarded or de-weighted accordingly. In some embodiments, the information regarding the blocked portions of the sky can be sent to a server and/or shared with other nearby mobile devices.