GNSS Signal Selection by Reception Time Comparison
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Solution Overview
Problem
Existing GNSS positioning and time synchronization technologies face challenges in achieving high accuracy due to the reception of invisible satellite signals caused by obstructions, which degrade the quality of satellite signals and affect positioning and time synchronization performance.
Innovation Solution
A satellite signal reception apparatus is developed, comprising a signal selection unit that selects a predetermined number of satellite signals based on their reception qualities, and a measurement unit that performs positioning using these selected signals. The signal selection unit compares expected and actual reception times to exclude invisible satellite signals, ensuring only direct wave signals are used for positioning and time synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If satellite signals are received in blocked environments, then the number of received satellite signals increases, but positioning accuracy deteriorates due to invisible satellite signals
Solution Approach 1:
The patent extracts and removes invisible satellite signals from the set of received satellite signals by comparing expected reception times (calculated from satellite ephemeris and initial position) with actual reception times. Signals with significant time differences are identified as invisible signals and excluded from positioning calculations, thereby maintaining positioning accuracy while preserving the quantity of usable signals in blocked environments.
Solution Approach 2:
The patent implements a feedback mechanism where the initial position estimate is used to calculate expected reception times, which are then compared with actual reception times to identify and exclude invisible signals. This feedback loop continuously refines the signal selection based on the calculated position, improving positioning accuracy iteratively even in blocked environments where signal reception is challenging.
2Productivity
If invisible satellite signals are included in positioning calculations, then positioning can be performed with more signals, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent extracts invisible satellite signals by comparing expected reception times (derived from satellite ephemeris and initial position) with actual reception times. Signals exhibiting significant time deviations are identified as invisible and removed from the positioning and time synchronization calculations, ensuring that only direct wave signals are used to maintain time synchronization accuracy while preserving positioning availability through the use of remaining visible signals.
3Device complexity
If signal selection based on reception quality alone is used, then processing is simple, but invisible satellite signals cannot be effectively excluded
Solution Approach 1:
The patent performs preliminary action by calculating expected reception times for all satellite signals before the actual positioning calculation using the initial position estimate. This preliminary calculation of expected times enables the subsequent identification and exclusion of invisible signals based on time comparison, providing an additional selection criterion beyond reception quality and improving signal selection accuracy without excessively increasing processing complexity.
Data Source
AI summary
A satellite signal reception apparatus includes: a signal selection unit that selects a predetermined number of satellite signals based on reception qualities of satellite signals received by a GNSS antenna; and a measurement unit that executes positioning by using the predetermined number of satellite signals selected by the signal selection unit and determines an initial estimated position, in which the signal selection unit selects a plurality of satellite signals to be used for positioning or time synchronization based on a comparison result obtained by comparing a reception time expected in a case where a satellite signal is received as a direct wave at the initial estimated position with an actual reception time of the satellite signal.