Redundant Clock Synchronization Using GNSS Time Pulses
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Solution Overview
Problem
Existing systems struggle to maintain precise time synchronization between redundant subsystems when GNSS reception is temporarily unavailable, leading to potential interference and degraded sensor performance in applications like autonomous vehicles.
Innovation Solution
A method and system for synchronizing clocks in redundant subsystems using a GNSS receiver and communication links, involving timepulses to align clocks to GNSS time and minimize drift, even in the absence of direct GNSS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clocks in redundant subsystems are synchronized using GNSS time directly, then time synchronization precision is improved, but system reliability deteriorates when GNSS reception is temporarily unavailable
Solution Approach 1:
The patent introduces a time pulse signal as an intermediary carrier that conveys GNSS time information through the communication link between subsystems. This mediator enables indirect time synchronization when direct GNSS reception is unavailable, resolving the contradiction by providing an alternative synchronization path that maintains both precision and reliability.
Solution Approach 2:
The system performs preliminary time synchronization to GNSS time when the GNSS receiver is available, establishing a reference time relationship between subsystems in advance. This preliminary action ensures that when GNSS reception becomes unavailable, the subsystems already have synchronized clocks and can maintain synchronization using the pre-established reference, thus improving reliability without sacrificing precision.
2Device complexity
If redundant subsystems operate independently without time synchronization, then system complexity is reduced, but harmful interference between subsystems increases
Solution Approach 1:
The communication link serves as an intermediary that carries time pulse signals between subsystems with minimal added complexity. This simple mediator enables time synchronization that prevents harmful interference (such as sensor conflicts and data inconsistency) without requiring complex synchronization protocols or additional hardware, thus resolving the contradiction effectively.
3Reliability
If multiple communication links are used for time synchronization in redundant systems, then synchronization reliability is improved, but device complexity increases
Solution Approach 1:
The communication link is designed to serve multiple functions: it carries both operational data between subsystems and time pulse signals for synchronization. This multi-functionality allows the system to achieve reliable time synchronization through an existing communication infrastructure without adding dedicated synchronization hardware or complex multi-link architectures, thus improving reliability while minimizing complexity.
Data Source
AI summary
Example embodiments relate to GNSS time synchronization in redundant systems. A redundant system configured with two subsystems may initially synchronize clocks from both subsystems to GNSS time from a GNSS receiver. The synchronization of the first subsystem's clock may involve using a first communication link that enables communication between the first subsystem and the GNSS receiver while the synchronization of the second subsystem's clock may involve using both the first communication link and a second communication link that enables communication between the subsystems. The redundant system may then synchronize the first subsystem's clock to the second subsystem's clock while the second subsystem's clock is still synchronized to GNSS time from the GNSS receiver based on timepulses traversing a pair of wires that connect the subsystems and the GNSS receiver.