Vehicle Sensor Clock Synchronization via PPS and Controller Intermediary
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems face challenges in efficiently and precisely synchronizing the clocks of multiple sensors in an autonomous vehicle, which is crucial for smooth coordination and accurate navigation.
Innovation Solution
A method and system for time synchronization in a vehicle, which includes a satellite navigation device transmitting a coordinated universal time (UTC) and a pulse per second (PPS) signal. This signal is used by the controller and LiDAR devices to synchronize their clocks, and the camera synchronizes its clock with the controller's clock using a network time protocol (NTP).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors use different clock synchronization methods, then each sensor can operate independently, but time synchronization precision deteriorates
Solution Approach 1:
The system divides sensors into two groups: high-precision sensors (LiDAR, satellite navigation device) that synchronize directly with the PPS signal, and other sensors (camera) that synchronize with the controller. This segmentation allows each group to use the most appropriate synchronization method for its requirements while maintaining overall system precision.
Solution Approach 2:
The controller acts as an intermediary between the PPS signal source and sensors that cannot directly receive PPS signals. The controller receives the PPS signal, processes it, and distributes synchronized time information to connected sensors, ensuring consistent time synchronization across the entire system.
2Measurement precision
If all sensors synchronize directly with the satellite navigation device, then time synchronization precision is improved, but system complexity increases
Solution Approach 1:
The system segments the synchronization architecture into a direct synchronization path (PPS signal to LiDAR and satellite navigation device) and an indirect synchronization path (PPS signal to controller to other sensors). This reduces complexity by allowing sensors to synchronize directly when possible and indirectly when necessary.
Solution Approach 2:
The controller serves as an intermediary that simplifies the system architecture by centralizing the reception and distribution of PPS signals. Sensors that cannot directly receive PPS signals synchronize with the controller, which has already synchronized with the PPS signal, reducing the overall system complexity.
3Measurement precision
If high-precision PPS signal is used for all sensors, then time synchronization accuracy is improved, but compatibility with sensors without direct PPS reception deteriorates
Solution Approach 1:
The controller acts as an intermediary that receives the high-precision PPS signal and distributes synchronized time information to sensors that cannot directly receive PPS signals. This maintains high synchronization accuracy while expanding compatibility to include various sensor types with different reception capabilities.
Solution Approach 2:
The controller performs multiple functions: it synchronizes with the PPS signal, processes time information, and distributes synchronized time to multiple types of sensors. This multi-functionality ensures both high precision and broad sensor compatibility within a single unified system.
Data Source
AI summary
A method for time synchronization in a vehicle may include transmitting, by a satellite navigation device to a controller and at least one LiDAR device, a UTC and a PPS signal. The satellite navigation device may have a first clock. The method may include synchronizing, by the controller, a second clock of the controller with the first clock of the satellite navigation device based on the PPS signal and the UTC. The method may include synchronizing, by the at least one LiDAR device, a third clock of the at least one LiDAR device with the first clock of the satellite navigation device based on the PPS signal and the UTC. The method may include synchronizing, by at least one camera, a fourth clock of the at least one camera with the second clock of the controller.