Dual Time Sources for Stable Autonomous Driving Synchronization
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Solution Overview
Problem
Current autonomous driving systems face challenges in providing a stable and reliable global time source, leading to potential security risks and traffic accidents due to time jumping and instability in time synchronization.
Innovation Solution
The proposed solution involves an apparatus with two independent time sources for different subsystems in an autonomous driving system. The first time source, based on a high-precision crystal oscillator, operates independently and maintains accuracy without relying on GNSS signals. The second time source traces a GNSS clock when available, ensuring coordinated universal time synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS signal is used as master clock for time synchronization, then coordinated universal time can be provided, 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 source segments: a first time source (crystal oscillator) for driving subsystems and a second time source (GNSS-based) for management subsystems. This segmentation isolates the critical driving functions from external GNSS interference while maintaining UTC synchronization for non-critical management functions.
Solution Approach 2:
Different quality levels of time sources are assigned to different subsystems based on their requirements. The first subsystem (autonomous driving) receives high-stability local crystal oscillator time, while the second subsystem (management services) receives GNSS-based UTC time. This local quality differentiation ensures critical functions have protected time sources.
2Reliability
If single time source is used for all subsystems, then system complexity is reduced, but time jumping affects security and reliability of autonomous driving algorithms
Solution Approach 1:
The time source architecture is segmented into two independent sources: a crystal oscillator-based time source for autonomous driving subsystems and a GNSS-based time source for management subsystems. This segmentation protects critical driving algorithms from time jumping while maintaining overall system functionality.
Solution Approach 2:
The system changes the stability parameter of time sources by using a crystal oscillator (high stability, isolated from external interference) for critical subsystems and GNSS (lower stability when unavailable) for non-critical subsystems. This parameter differentiation resolves the reliability-complexity contradiction.
3Measurement precision
If GNSS signal tracing is used for time synchronization, then coordinated universal time is achieved, but time jumping occurs during vehicle driving process
Solution Approach 1:
The system segments time source usage by function: crystal oscillator for continuous stable timing in autonomous driving, GNSS for UTC synchronization in management services. This prevents GNSS signal interruptions from affecting the continuity of critical time synchronization.
Solution Approach 2:
The crystal oscillator acts as an intermediary time source that provides continuous stable timing independently of GNSS signal availability. It mediates between the need for UTC accuracy and the requirement for continuous stable time synchronization during vehicle operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a continuous and stable time synchronization service, isolating the clock sources to prevent external interference, and ensuring secure operation of the autonomous driving system by preventing time jumping and meeting real-time requirements.
Implementation Method 1
a first processor and a first crystal oscillator connected to the first processor. The first processor is configured to provide a first time source for a first subsystem by using the first crystal oscillator
Implementation Method 2
provide a second time source for a second subsystem based on a received satellite time signal
Data Source
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AI summary
Embodiments of the present invention disclose a method and an apparatus for providing a time source for autonomous driving, 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 invention, 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.