GNSS Satellite Selection Using LOS Filtering for Accurate Positioning
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Solution Overview
Problem
GNSS systems face challenges in achieving accurate positioning due to obstructions such as mountains, canyons, and tunnels, leading to multipath interference and reduced line of sight, which results in measurement errors and inaccurate position determination.
Innovation Solution
A user equipment (UE) method that filters satellite vehicles (SVs) based on line of sight (LOS) measurement errors, adding SVs with LOS to an active list and discarding those without, ensuring a threshold is met for accurate positioning, optionally incorporating signals from prior epochs to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS signals are used for position determination, then global positioning is achieved, but measurement precision deteriorates in obstructed environments due to multipath interference
Solution Approach 1:
The patent extracts and removes multipath interference components from the signal processing. By detecting signals from multiple satellites and analyzing their signal characteristics, the system identifies and excludes multipath interference components, retaining only direct line-of-sight signals for accurate position determination.
Solution Approach 2:
The patent introduces an intermediary processing layer that analyzes signal characteristics before position calculation. This intermediary layer detects and evaluates signal quality metrics, acting as a mediator between raw satellite signals and final position data, filtering out corrupted multipath signals.
2Reliability
If signals from multiple satellite vehicles are used, then position determination reliability is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The patent segments the signal processing into distinct functional modules: satellite signal acquisition, signal characteristic analysis, multipath interference detection, and position calculation. This segmentation allows complex processing to be divided into manageable stages, improving reliability while controlling complexity through modular architecture.
Solution Approach 2:
The patent utilizes parameter changes in signal characteristics (such as signal strength, arrival time, and phase information) to distinguish between direct and multipath signals. By monitoring changes in these parameters, the system can reliably identify valid satellites without requiring overly complex processing algorithms.
Data Source
AI summary
A user equipment includes processor(s) configured to: determine a first acquired satellite vehicle (SV) list including first SV(s) from which a user equipment (UE) is receiving signals within a current epoch; for each first SV in the first acquired SV list, determine whether a first measurement error associated with the first SV indicates a line of sight (LOS) between the UE and the first SV; for each first SV in the first acquired SV list, in response to the first measurement error indicating the LOS between the UE and the first SV, add the first SV to an active SV list; determine whether a number of SVs in the active SV list meets a threshold; and in response to the number of SVs in the active SV list meeting the threshold, determine a position of the UE based on the signals received from the SVs in the active SV list.