Optical Position Sensor for Thermal Drift Compensation in LIDAR
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Solution Overview
Problem
Existing LIDAR systems face challenges in accurate distance measurement due to thermal variations affecting dispersive scanning devices and the complexity of maintaining an unchanging frequency curve, along with safety concerns requiring monitoring of luminous power.
Innovation Solution
Incorporating an optical position sensor downstream of the dispersive element to ascertain beam directions independently of thermal changes and using sensor signals for closed-loop control of the light source unit, eliminating the need for phase locked loop electronics and enabling monitoring of luminous power for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal stabilization measures are implemented for dispersive scanning devices, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces thermal stabilization mechanisms with an optical position sensor that directly measures beam position. Instead of mechanically stabilizing the dispersive scanning device through temperature control, the system uses optical detection to ascertain beam directions independently of thermal changes, thereby eliminating complex thermal management hardware while maintaining measurement precision.
Solution Approach 2:
The patent implements feedback by using the optical position sensor to detect actual beam positions and using this information to compensate for thermal drift effects. The sensor signals provide real-time feedback about beam direction changes due to thermal variations, allowing the system to correct measurements without requiring preventive thermal stabilization.
2Measurement precision
If phase locked loop electronics are used for closed-loop control of optical phase, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex phase locked loop electronics with a simplified system using an optical position sensor and direct sensor signal processing. Instead of using electronic phase locking mechanisms to maintain frequency curve stability, the system directly measures beam position optically and uses these measurements for distance calculation, eliminating the need for sophisticated electronic control circuits.
3Reliability
If monitoring of luminous power is implemented for safety, then safety is improved, but device complexity increases
Solution Approach 1:
The patent makes the optical position sensor serve multiple functions: it simultaneously determines beam directions for distance measurement and monitors luminous power for safety. By using the same sensor for both measurement and safety monitoring, the system avoids adding separate monitoring hardware, thereby improving safety without proportionally increasing device complexity.
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 image reconstruction and simplifies the system by avoiding thermal stabilization and reducing complexity, while ensuring safe operation by monitoring luminous power without additional complexity.
Implementation Method 1
at least one dispersive element disposed in the signal path of the optical signal
Implementation Method 2
at least one optical position sensor disposed downstream of this dispersive element in the signal path
Implementation Method 3
a measurement principle also referred to as LIDAR is known, amongst others, in which an optical signal is emitted to the relevant object and evaluated after back-reflection has taken place at the object
Data Source
AI summary
An apparatus for ascertaining a distance to an object has a light source unit for emitting an optical signal with a time-varying frequency, an evaluation device for ascertaining a distance to the object based on (a) a measurement signal that arose from the signal and was reflected at the object and (b) a reference signal that was not reflected at the object. The apparatus has also a dispersive element disposed in the signal path of the optical signal and an optical position sensor disposed downstream of this dispersive element in the signal path.