Domain Controller Time Synchronization for Driving Timestamp Alignment
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Solution Overview
Problem
Intelligent driving devices face security risks due to large time deviations on local clocks when GNSS or network signals are lost, leading to incorrect timestamp synchronization and decision-making issues.
Innovation Solution
A time synchronization method that determines the driving status of the device to perform synchronization only when necessary, using different synchronization manners based on time differences and clock frequency adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time synchronization is performed continuously on the local clock, then time accuracy is improved, but system security deteriorates due to time jumps during critical driving operations
Solution Approach 1:
The patent implements dynamic time synchronization by adjusting synchronization behavior based on driving status. When the vehicle is in autonomous or assisted driving mode, time synchronization is suspended to prevent time jumps that could disrupt sensor data timestamps and control decisions. When the vehicle is in manual mode or parked, synchronization is performed to maintain time accuracy. This dynamic adaptation resolves the contradiction by making the system flexible rather than fixed.
Solution Approach 2:
The patent changes the parameter of synchronization frequency based on driving status. Instead of continuous synchronization, the system modifies the synchronization interval or enables/disables synchronization entirely based on the current operating mode. This parameter change allows the system to prioritize security during critical operations while maintaining accuracy during non-critical periods.
2Reliability
If time synchronization is delayed until signal is available, then system security is improved, but time deviation accumulates worsening time accuracy
Solution Approach 1:
The patent performs preliminary time synchronization when the vehicle is in manual mode or parked, before entering autonomous driving mode. This preliminary action ensures that the local clock is synchronized in advance, reducing accumulated deviation. When autonomous mode is activated, the system relies on this preliminary synchronization rather than performing continuous updates, thus maintaining both security and acceptable accuracy.
Solution Approach 2:
The patent implements periodic time synchronization at specific intervals or under specific conditions (e.g., when in manual mode, when parked, or when signal becomes available). Instead of continuous synchronization, the system uses periodic updates that are strategically timed to avoid disrupting autonomous operations while still maintaining time accuracy within acceptable bounds.
3Measurement precision
If sensors synchronize their clocks independently, then individual sensor time accuracy is improved, but overall timestamp alignment deteriorates due to different synchronization speeds
Solution Approach 1:
The patent merges the time synchronization function into the domain controller rather than allowing each sensor to synchronize independently. The domain controller acts as a central time source that distributes synchronized time to all sensors. This consolidation ensures that all sensors operate from a single time reference, guaranteeing timestamp alignment across the entire sensor network while maintaining individual time accuracy.
Solution Approach 2:
The domain controller serves as an intermediary between the external time source and individual sensors. Instead of sensors directly synchronizing with external sources at different times and speeds, the domain controller receives time information and distributes it uniformly to all sensors. This intermediary role ensures coordinated synchronization and consistent timestamps across all sensors.
Data Source
AI summary
A time synchronization method includes obtaining time information of an external clock source and a current driving status of the intelligent driving device; then determining whether the current driving status is a driving status in which time synchronization processing needs to be performed on a local clock of the domain controller; and when the current driving status is the driving status in which time synchronization processing needs to be performed, performs time synchronization processing on the local clock based on the time information of the external clock source.