Dual Time Source Architecture for Autonomous Driving Synchronization
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Solution Overview
Problem
Current autonomous driving systems face instability and security risks due to unreliable global time synchronization, particularly when GNSS signals are unavailable, leading to potential traffic accidents and system failures.
Innovation Solution
The implementation of a dual-time source system using a first crystal oscillator for driving services and a second time source based on satellite signals for management services, ensuring independent and stable time synchronization across the autonomous driving system, even in scenarios without GNSS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS signal is used as master clock for time synchronization, then time reference can be obtained when signal is available, but time jumping and instability occur when signal is unavailable or shielded
Solution Approach 1:
The autonomous driving system is divided into two independent time synchronization systems: a first time synchronization system for driving services using crystal oscillator, and a second time synchronization system for management services using GNSS signal. This segmentation isolates the critical driving services from GNSS signal interference while maintaining separate time sources for different functional requirements.
Solution Approach 2:
Different time synchronization qualities are applied to different subsystems based on their specific requirements. The driving service subsystem uses high-stability crystal oscillator for continuous reliable timing, while the management service subsystem uses GNSS for coordinated universal time. Each subsystem receives time synchronization tailored to its local needs.
2Device complexity
If single time source is used for all subsystems, then system complexity is reduced, but security and reliability of autonomous driving algorithm are compromised
Solution Approach 1:
The time source configuration is segmented into two independent systems with separate time sources, processors, and synchronization protocols. The first system uses crystal oscillator for driving services while the second uses GNSS for management services, eliminating single-point failure risks while maintaining manageable complexity through clear functional separation.
Solution Approach 2:
The processor acts as an intermediary that selectively distributes time synchronization signals from appropriate sources to different subsystems. It receives crystal oscillator signals for driving services and GNSS signals for management services, then distributes the appropriate time reference to each subsystem based on their specific requirements.
3Measurement precision
If GNSS signal tracing is used for time synchronization, then coordinated universal time can be obtained, but time jumping occurs affecting security and reliability
Solution Approach 1:
The time synchronization function is segmented into two independent pathways: one using crystal oscillator for continuous stable timing of driving services, and another using GNSS for coordinated universal time of management services. This segmentation prevents GNSS signal instability from affecting critical driving operations while still obtaining UTC when needed for management functions.
Solution Approach 2:
Different time accuracy requirements are satisfied locally for different subsystems. The driving service subsystem requires continuous stable timing provided by crystal oscillator, while the management service subsystem requires coordinated universal time provided by GNSS. Each subsystem receives the time quality appropriate to its local functional requirements.
Data Source
AI summary
A method and an apparatus for providing a time source for autonomous driving are provided, which may be applied to autonomous driving of a vehicle in the field of artificial intelligence. The method includes: providing a first time source for a first subsystem of an autonomous driving system by using a first crystal oscillator, and providing a second time source for a second subsystem of the autonomous driving system based on a received satellite time signal. According to embodiments of the present disclosure, a stable and reliable global time source reference can be provided for the autonomous driving system, to ensure secure operation of the autonomous driving system, and meet a requirement of the system for coordinated universal time.