Distributed GNSS Integrity Monitoring for Outage-Resilient Positioning
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Solution Overview
Problem
Traditional GNSS positioning systems face challenges in ensuring integrity and availability, particularly in autonomous vehicles, due to communication link outages and latency, leading to insufficient alert times and unreliable positioning solutions.
Innovation Solution
A distributed integrity monitoring system that shares the responsibility for integrity between a GNSS receiver and a corrections service, using an age of integrity approach to ensure scalable and modular positioning solution integrity, with integrity monitoring performed by a computing system that includes a corrections generator and integrity monitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional centralized integrity monitoring is used, then system complexity is reduced, but reliability deteriorates due to communication link outages and latency
Solution Approach 1:
The patent divides integrity monitoring into two separate functions: (1) corrections service integrity monitoring performed by the corrections service itself, and (2) positioning service integrity monitoring performed by the positioning engine. This segmentation allows each component to independently monitor its own integrity, eliminating the single point of failure in traditional centralized monitoring and improving overall system reliability during communication outages.
Solution Approach 2:
The corrections service performs self-integrity monitoring by monitoring its own corrections data for integrity violations. This self-service approach ensures that the corrections service can detect and report its own integrity issues without relying on external monitoring systems, thereby maintaining reliability even when communication links are compromised.
2Loss of time
If traditional time-to-alert requirements are used, then alert timeliness is improved, but availability deteriorates due to communication link outages
Solution Approach 1:
The system pre-calculates and transmits integrity monitoring results with corrections data. When communication links are available, integrity information is prepared in advance and sent alongside corrections. During communication outages, the positioning engine can continue to use this pre-transmitted integrity information, maintaining positioning availability without requiring real-time communication.
Solution Approach 2:
The patent implements dynamic integrity monitoring where the positioning engine adjusts its integrity assessment based on the age of integrity information. When fresh integrity data is available, it uses that; when communication is lost, it transitions to using older integrity data with appropriate aging adjustments, allowing the system to maintain availability while accounting for time delays.
3Reliability
If distributed integrity monitoring is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts integrity monitoring functionality from the corrections service and places it in the positioning engine. The positioning engine receives corrections data and independently performs integrity monitoring on the positioning service, separating the concerns of corrections generation from integrity assessment. This extraction reduces the complexity burden on the corrections service while improving overall system reliability.
Data Source
AI summary
A method can include receiving satellite observations, determining GNSS corrections, monitoring the GNSS corrections, transmitting the GNSS corrections and monitor result, and determining a GNSS receiver positioning solution.