Automotive Network Time Sync Validation Across Mixed Buses
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Solution Overview
Problem
Existing time synchronization methods for communication networks in automated vehicles do not adequately ensure the integrity required for safety integrity levels such as ASIL B or higher, which is crucial for advanced autonomous driving functions.
Innovation Solution
A method involving a master clock sending synchronization messages to control units and central validators, with local time synchronization and comparison, and error messaging if differences exceed predefined thresholds, ensuring time synchronization integrity across multiple communication networks with different standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time synchronization is performed using standard protocols (IEEE 802.1AS or IEEE 1588), then time synchronization functionality is achieved, but the integrity and reliability required for ASIL B or higher safety levels are not ensured
Solution Approach 1:
The patent introduces a central validator as an intermediary component that mediates between the master clock and control units. This validator receives synchronized local times from control units, compares them against expected values, and validates whether the time synchronization meets ASIL B or higher integrity requirements, thereby ensuring reliability without requiring complex modifications to the standard protocols
Solution Approach 2:
The patent implements a feedback mechanism where control units send their synchronized local times back to the central validator, which then compares these times against the master time and validates the synchronization accuracy. This feedback loop enables continuous monitoring and validation of time synchronization integrity, ensuring ASIL B compliance while maintaining manageable system complexity
2Adaptability or versatility
If multiple communication busses are used for different ECUs, then functional requirements for automated driving are met, but time synchronization integrity across different communication standards becomes difficult to ensure
Solution Approach 1:
The patent creates a universal time synchronization validation framework that can operate across multiple communication busses and standards (CAN, LIN, Ethernet, FlexRay). The central validator and control units implement a standardized time validation protocol that works independently of the underlying communication medium, enabling multi-communication bus support while maintaining consistent time synchronization accuracy measurements across all standards
3Reliability
If time synchronization is implemented without validation, then system complexity is reduced, but safety integrity levels (ASIL B or higher) cannot be fulfilled
Solution Approach 1:
The patent segments the time synchronization validation function into distinct modular components: control units that generate and send synchronized local times, a central validator that performs the comparison and validation logic, and a clear separation between time synchronization and validation functions. This segmentation enables ASIL B compliance through systematic validation while keeping each component's complexity manageable and well-defined
Data Source
AI summary
A method for validating time synchronization in a communication network of an automated vehicle includes sending a time synchronization message from a master clock to two control units of a first communication network, respectively, wherein the time synchronization message includes a master time; synchronizing a local time of the two control units of the first communication network to the received master time, respectively; sending the synchronized local times of the two control units of the first communication network to a central validator of the first communication network, respectively; comparing, at the central validator of the first communication network, the received synchronized local times of the two control units of the first communication network to each other; and, if a difference between the received synchronized local times is larger than a predefined first threshold, outputting an error message from the central validator of the first communication network to the automated vehicle.