Vehicle Sensor Calibration via Master Clock Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The synchronization of sensor signals in autonomous vehicles is hindered by delays between different sensors, such as cameras, LIDAR, and radar units, leading to time misalignments and errors in event reconstruction and vehicle control.
Innovation Solution
A method and system for calibrating sensor signals by using a calibration signal emitting unit to send light indications and synchronization signals, determining delays, and calculating calibration factors for each sensor, allowing for synchronized data processing based on a master clock time, which can be the system clock or a selected sensor clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors with different operating speeds are used to increase detection capability, then measurement precision and reliability are improved, but time synchronization accuracy deteriorates due to varying frame rates and scan rates
Solution Approach 1:
The patent applies preliminary action by sending calibration signals (light indications and synchronization signals) before actual sensor operations to establish reference timing relationships. The calibration unit determines delays between sensors by comparing timestamps of calibration signals with sensor readings, allowing the system to pre-calculate compensation values that are applied during actual operation to synchronize multi-sensor data.
2Measurement precision
If the number of sensors is increased to improve detection coverage, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a calibration unit as an intermediary component that manages the complexity of synchronizing multiple sensors. This calibration unit coordinates calibration activities, sends control signals to the calibration signal emitting unit, receives sensor data, and calculates calibration factors. By centralizing the synchronization management in this intermediary component, the system can handle multiple sensors without proportionally increasing overall system complexity.
3Adaptability or versatility
If sensors with different operating speeds are used to improve detection capability, then adaptability is improved, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting timing parameters based on measured delays. The calibration unit determines specific delay values for each sensor combination and uses these to calculate calibration factors that adjust the timing of sensor signals. This allows the system to accommodate different sensor operating speeds (frame rates, scan rates) by changing the temporal parameters of signal processing rather than requiring all sensors to operate at the same speed.
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 approach ensures accurate synchronization of sensor signals, reducing delays and errors, thereby enhancing the reliability and precision of vehicle control systems, especially with the increasing number of sensors in future vehicles.
Implementation Method 1
sending at least one light indication, for example by turning on or off a light emitter, to a sensor from a calibration signal emitting unit
Data Source
AI summary
A method for calibrating sensor signals in networks in a vehicle, wherein a number of sensors are arranged in the vehicle including one or more cameras, one or more LIDAR, and one or more radar units each communicating with a electronic control unit over a network, the electronic control unit communicating with vehicle elements including braking system and steerings system. The method includes receiving incoming signals from sensors at a calibration unit, wherein the incoming signals contain information of a detected object or signal, determining a delay for each received signal relative to a predetermined master clock time; and determining one calibration time for all the received signals based on the determined delays relative the predetermined master clock time.