Vessel Positioning Ambiguity Detection via Dead-Reckoning Verification
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Solution Overview
Problem
Existing vessel positioning systems using Global Navigation Satellite Systems (GNSS) face challenges in detecting ambiguities caused by artificial errors and signal interference, which can lead to inaccurate positioning information, making it difficult for users to recognize inaccuracy in vessel position data.
Innovation Solution
A system and method that compares orbit information of GNSS satellites with dead-reckoning data using a direction sensor and speed sensor to detect ambiguities by calculating predicted distances and pseudoranges, monitoring for errors in satellite signals, and using equations to determine vessel positions before and after a specific time interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GNSS satellite signals are used for vessel positioning, then positioning coverage over the entire earth is achieved, but positioning accuracy deteriorates due to artificial errors and signal interference
Solution Approach 1:
The patent introduces an intermediary verification mechanism that compares GNSS positioning results with independent dead-reckoning calculations. This intermediary check acts as a mediator to detect and filter out inaccurate positioning data caused by artificial errors or signal interference, while maintaining the broad coverage advantage of GNSS systems.
Solution Approach 2:
The system implements feedback by continuously monitoring the consistency between GNSS-derived position and dead-reckoning position. When discrepancies exceed predetermined thresholds, the system generates feedback signals to alert users or switch to alternative positioning methods, thereby maintaining accuracy while preserving coverage.
2Measurement precision
If dead-reckoning is used to calculate vessel position, then positioning accuracy is improved, but device complexity increases due to additional sensors and calculations
Solution Approach 1:
The patent applies partial action by using dead-reckoning only as a verification tool rather than the primary positioning method. The system performs dead-reckoning calculations only when needed to check GNSS accuracy, rather than continuously relying on it, thus reducing the complexity burden while maintaining accuracy improvements.
Solution Approach 2:
The dead-reckoning module serves multiple functions: it provides alternative positioning when GNSS fails, verifies GNSS accuracy through comparison, and can operate independently for navigation. This multi-functionality justifies the added complexity by providing versatile positioning capabilities.
3Reliability
If continuous monitoring of positioning errors is implemented, then reliability of positioning information is improved, but loss of time increases due to additional processing
Solution Approach 1:
The system implements periodic action by monitoring positioning errors at specific intervals rather than continuously. The error detection occurs at predetermined time intervals or when certain conditions are met, providing reliable positioning verification while minimizing processing time and computational overhead.
Solution Approach 2:
The system performs preliminary actions by pre-establishing the dead-reckoning calculation framework and error threshold criteria before actual positioning operations. This preparation allows for rapid error detection and verification during operation, reducing real-time processing requirements while maintaining high reliability.
Data Source
AI summary
The present invention relates to a system for detecting ambiguities in a satellite signal for the GPS tracking of vessels, which includes: a GNSS receiving unit obtaining a vessel position using a plurality of satellites; a vessel position calculating unit calculating a second vessel position from a first vessel position after a specific amount of time elapses using dead-reckoning; a distance calculating unit calculating prediction distances between each of the satellites and the vessel and an error monitoring unit comparing the calculated prediction distances between the satellites and the vessel, and pseudoranges between the satellites and the GNSS receiving unit at the second vessel position, and monitoring for the occurrence of errors at the satellites on the basis of the existence of an increase in errors at each of the satellites.