LIDAR Sensor Propagation Time Calibration via Internal Light Scattering
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Solution Overview
Problem
Conventional LIDAR sensor calibration methods require a reference surface for decoupling light pulses, which limits flexibility and increases complexity, especially when dealing with temperature changes and aging effects that alter electronic signal propagation times.
Innovation Solution
A method where the detector surface is illuminated with decoupled light via a light-scattering system, eliminating the need for a reference surface and allowing each optoelectronic element to use detection times of decoupled light pulses as a time reference for compensating electronic signal propagation times, enabling high spatial resolution calibration with minimal additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference surface is used for decoupling light pulses in conventional calibration methods, then propagation time calibration can be performed, but the device complexity increases and flexibility is limited
Solution Approach 1:
The invention extracts the calibration function from a separate reference surface and integrates it into the detector surface itself. The beam splitter directs a portion of the light pulses to the detector surface, allowing calibration measurements to be performed using the same detector elements that perform actual measurements, thereby eliminating the need for a separate reference surface and reducing system complexity.
Solution Approach 2:
The detector surface serves dual purposes: it performs both actual distance measurements of objects and propagation time calibration measurements. By making the detector surface universal for both measurement functions, the system eliminates the need for dedicated reference surface hardware, thereby reducing device complexity while maintaining calibration accuracy.
2Measurement precision
If a reference surface is used for calibration, then propagation time calibration is possible, but the ease of operation decreases due to symmetry requirements
Solution Approach 1:
The invention deliberately creates an asymmetric calibration setup where the beam splitter directs light to the detector surface at different optical path lengths. This asymmetric approach eliminates the need for symmetric arrangements between reference surface and detector surface, simplifying the operational requirements and making the calibration process more flexible and easier to implement.
3Measurement precision
If propagation time calibration is performed manually during production, then initial calibration accuracy is achieved, but productivity decreases and continuous calibration is not possible
Solution Approach 1:
The invention enables continuous propagation time calibration by integrating the calibration functionality into the normal operation of the LIDAR sensor. The beam splitter continuously directs a portion of the emitted light pulses to the detector surface for calibration measurements, allowing calibration to occur continuously during operation rather than only during periodic manual intervention, thereby maintaining high productivity while ensuring continuous calibration accuracy.
4Device complexity
If the detector surface is used for both measurement and calibration, then device complexity is reduced, but measurement precision may be affected by signal interference
Solution Approach 1:
The invention segments the light pulses into two distinct paths using the beam splitter: one path for actual distance measurements and another path for calibration measurements. This segmentation allows the system to separate calibration signals from measurement signals in the time domain, preventing interference between the two functions while still using the same detector surface, thereby maintaining both simplicity and precision.
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 simplifies LIDAR sensor design, allows for continuous calibration during operation, and effectively compensates for temperature-induced changes in propagation times, ensuring accurate object distance measurement with high spatial resolution.
Implementation Method 1
decoupling, for at least some of the light pulses, a portion of the light, using a beam splitter at the light source
Implementation Method 2
the detector surface is illuminated with the decoupled light via a light-scattering system
Implementation Method 3
a detector surface with a plurality of optoelectronic elements for receiving light pulses of the light source reflected on objects and for converting these light pulses into electronic signals
Data Source
AI summary
A method for propagation time calibration of a LIDAR sensor which includes a pulsed light source, a detector surface with a plurality of optoelectronic elements for receiving light pulses of the light source reflected on objects and for converting these light pulses into electronic signals, and an electronic evaluation circuit for detecting the light pulses and for measuring the propagation times thereof. In the method, the measured propagation times are corrected with respect to the propagation times of the electronic signals in the evaluation circuit by decoupling, for at least some of the light pulses, a portion of the light, using a beam splitter at the light source, and using detection times of the decoupled light pulses as a time reference. The detector surface is illuminated with the decoupled light via a light-scattering system and used for detecting the decoupled light pulses.