Centralized Time Sync Hub for Autonomous Vehicle Sensors
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Solution Overview
Problem
Autonomous driving vehicles face challenges in accurate time synchronization of sensor data due to the variability and cost of high-precision crystal oscillators, leading to confusion and imprecision in timestamp generation across different sensors and devices.
Innovation Solution
A hardware centralized time synchronization hub is introduced, utilizing TX and RX timestamp generators synchronized with a GPS pulse signal to provide precise timestamps to sensors, ensuring accurate timekeeping and synchronization across the vehicle's systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high precision crystal oscillators are used for time generation, then time synchronization accuracy is improved, but system cost increases
Solution Approach 1:
The patent replaces expensive high-precision crystal oscillators with inexpensive standard clock sources (such as 16MHz or 32MHz oscillators) combined with a time synchronization hub that uses software-based timestamp generation. The hub compensates for the lower precision of cheap oscillators by centralizing time management and generating timestamps through coordinated software control, thus achieving acceptable synchronization accuracy without the high cost of precision hardware oscillators.
Solution Approach 2:
The time synchronization hub acts as an intermediary between multiple sensors and the host system. It receives clock signals from standard oscillators, generates centralized timestamps, and distributes them to various sensors. This mediator approach allows the use of inexpensive clock sources while maintaining system-wide time synchronization through the hub's coordinated timestamp management.
2Adaptability or versatility
If multiple clock sources from different sensors are used, then adaptability is improved, but time synchronization precision deteriorates due to confusion and variability
Solution Approach 1:
The patent merges multiple distributed clock sources into a single centralized time management system. The time synchronization hub consolidates timestamp generation for all sensors, replacing the previous approach where each sensor had its own independent clock. This unification eliminates the confusion and precision loss caused by multiple varying clock sources while maintaining adaptability to different sensor types through the hub's standardized interface.
Solution Approach 2:
The time synchronization hub provides a universal timestamp generation service that works with multiple types of sensors (cameras, LIDAR, radar, etc.). Instead of requiring each sensor to have its own specialized clock source, the hub serves as a multi-functional time provider that adapts to different sensor requirements through software configuration while maintaining centralized precision control.
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 solution enhances the accuracy and efficiency of motion planning and control in autonomous vehicles by providing a unified and precise timestamp system, reducing the reliance on costly high-precision oscillators and improving sensor data synchronization.
Implementation Method 1
utilizing TX and RX timestamp generators synchronized with a GPS pulse signal to provide precise timestamps to sensors
Data Source
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AI summary
In one embodiment, a sensor unit to be utilized in an autonomous driving vehicle (ADV) includes a sensor interface coupled to a number of sensors mounted on a number of locations of an autonomous driving vehicle (ADV). The sensor unit includes a host interface to be coupled to a host system, where the host system is configured to perceive a driving environment surrounding the ADV based on sensor data obtained from the sensors and to plan a path to autonomously drive the ADV. The sensor unit includes a time synchronization hub device coupled to the sensor interface. The time synchronization hub device includes one or more TX and/or RX timestamp generators coupled to a time source, where the TX/RX timestamp generators generate TX/RX timestamps based on a time obtained from the time source to provide the TX/RX timestamps to one or more of the sensors.