Hardware Time Sync for Heterogeneous Autonomous Vehicle Sensors
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Solution Overview
Problem
Existing systems for autonomous vehicle navigation lack effective methods for synchronizing multiple heterogeneous sensors, leading to timing discrepancies and inefficiencies in data processing.
Innovation Solution
The implementation of a hardware-based time synchronization system that generates output trigger pulses with frequencies matching the target operating frequencies of various sensors, ensuring accurate synchronization across multiple heterogeneous sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple heterogeneous sensors are used for autonomous vehicle navigation, then sensing capabilities and coverage are improved, but timing synchronization and data processing efficiency deteriorate
Solution Approach 1:
The patent divides the synchronization task into separate trigger pulse generation units, each dedicated to a specific sensor type. Each unit independently generates trigger pulses at the appropriate frequency for its associated sensor, eliminating the need for complex centralized synchronization and reducing timing delays across heterogeneous sensors.
Solution Approach 2:
The system pre-generates trigger pulses at the target operating frequencies of various sensors before data acquisition begins. By preparing the timing signals in advance and distributing them to respective sensors, the system ensures synchronized operation without introducing processing delays during actual sensing operations.
2Adaptability or versatility
If multiple heterogeneous sensors operate at different frequencies, then sensor functionality and coverage are improved, but system complexity and coordination difficulty increase
Solution Approach 1:
The patent employs a universal trigger pulse generation mechanism that can accommodate multiple sensor types operating at different frequencies. The system uses a common reference clock and frequency division/multiplication circuits to generate appropriate trigger signals for various sensors (cameras, LIDAR, radar, etc.), simplifying coordination while maintaining diverse sensor functionality.
Solution Approach 2:
The patent introduces a central clock unit as an intermediary that provides a common time reference to all sensor trigger generation units. This mediator coordinates the operation of heterogeneous sensors by distributing synchronized trigger signals at appropriate frequencies, reducing system complexity while maintaining individual sensor functionality.
3Productivity
If sensor trigger frequencies are adjusted to match target operating frequencies, then data processing efficiency is improved, but timing precision and synchronization accuracy may deteriorate
Solution Approach 1:
The patent carefully controls the transformation of trigger pulse frequencies using precise frequency division and multiplication circuits. By maintaining integer ratios in frequency transformations and using high-stability reference clocks, the system achieves both target operating frequency matching and high synchronization accuracy, resolving the contradiction between processing efficiency and timing precision.
Data Source
AI summary
Devices, systems, and methods for hardware-based time synchronization for heterogenous sensors are described. An example method includes generating a plurality of input trigger pulses having a nominal pulse-per-second (PPS) rate, generating, based on timing information derived from the plurality of input trigger pulses, a plurality of output trigger pulses, and transmitting the plurality of output trigger pulses to a sensor of a plurality of sensors, wherein a frequency of the plurality of output trigger pulses corresponds to a target operating frequency of the sensor, wherein, in a case that a navigation system coupled to the synchronization unit is functioning correctly, the plurality of input trigger pulses is generated based on a nominal PPS signal from the navigation unit, and wherein, in a case that the navigation system is not functioning correctly, the plurality of input trigger pulses is generated based on a simulated clock source of the synchronization unit.