Dual Time Domain Synchronization for Intelligent Driving Control Units
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Solution Overview
Problem
Intelligent driving systems face inaccuracies in time stamps due to time jumps, leading to failures in multi-sensor data fusion and affecting operational stability.
Innovation Solution
A time synchronization method that sets both a universal time domain using UTC time and a local time domain using PTP time, synchronizing control units within intelligent driving devices via gPTP and NTP protocols, and adding PTP time stamps to sensor data to ensure accurate time synchronization across multiple control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UTC time is used for time synchronization in intelligent driving systems, then time synchronization is implemented across different sensors, but time jumps occur due to environmental impact and power-on conditions after sleep mode, resulting in inaccurate time stamps
Solution Approach 1:
The patent introduces a router as an intermediary device between the network unit and control units. The router generates PTP time based on crystal oscillators and provides it to control units through a dedicated time synchronization network. This intermediary approach isolates control units from direct UTC time dependencies, preventing time jumps while maintaining accurate time synchronization for sensor data fusion.
2Measurement precision
If a single time domain is used for synchronization, then the system structure is simple, but time synchronization accuracy is insufficient for multi-sensor data fusion
Solution Approach 1:
The patent divides the time synchronization system into two independent time domains: UTC time domain for overall system time reference and PTP time domain for precise sensor data synchronization. Each time domain serves specific functions, with UTC providing coarse time reference and PTP providing microsecond-level precision for data fusion. This segmentation achieves high synchronization accuracy without excessive complexity.
Solution Approach 2:
The patent adds a temporal dimension by introducing dual time domains operating at different precision levels. Instead of using a single time scale, the system operates with UTC for general timekeeping and PTP for precise measurement, creating a multi-layered time structure that enhances synchronization accuracy while maintaining manageable system complexity.
Data Source
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AI summary
The disclosure specifically provides a time synchronization method, a time synchronization anomaly diagnosis method, and a driving device. The time synchronization method of the disclosure is applied to an intelligent driving device, the driving device includes a plurality of control units, a plurality of sensors, a network unit, and a router connecting the network unit to the plurality of control units, and the method includes the following steps: setting a universal time domain and a local time domain, where the universal time domain uses UTC time obtained by the network unit, and the local time domain uses PTP time generated by a crystal oscillator of a network port of the router or a crystal oscillator of one of the plurality of control units as a PTP time source; and synchronizing each of the plurality of control units to the UTC time and the PTP time. Setting the UTC time and the PTP time and synchronizing the UTC time and the PTP time to each control unit achieve time synchronization of the double time domains for the control units.