LiDAR Sensor Self-Calibration Using Optical Splitter
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Solution Overview
Problem
LiDAR sensors face challenges in maintaining constant gain of avalanche photodiodes due to temperature variations, leading to inconsistent reflectance measurements and potential false detection events, especially in extreme temperatures or when heat management is difficult.
Innovation Solution
The LiDAR sensor employs an optical splitter to split the laser pulse into calibration and external pulses, allowing the processor to adjust the bias voltage based on the strength of the calibration pulse, thereby maintaining constant gain without temperature measurement, ensuring consistent reflectance calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If temperature measurement devices are used to compensate for temperature variations, then gain stability is improved, but device complexity increases
Solution Approach 1:
The LiDAR sensor performs self-calibration by using its own laser pulse and internal components (optical splitter, photodetector) to generate calibration data. The processor analyzes the calibration pulse strength and automatically adjusts the bias voltage to maintain constant gain, eliminating the need for external temperature sensors or manual intervention.
Solution Approach 2:
The system dynamically changes the bias voltage parameter based on real-time calibration pulse measurements. By monitoring the strength of calibration pulses and adjusting the bias voltage accordingly, the system maintains constant photodetector gain despite temperature variations, using electrical parameter adjustment instead of thermal measurement.
2Measurement precision
If calibration pulses are continuously monitored and bias voltage is adjusted, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The calibration pulse measurement and external object measurement functions are merged into a single photodetector and processing system. The same photodetector detects both calibration pulses (for gain monitoring) and reflected pulses (for distance and reflectance measurement), eliminating the need for separate sensing paths and reducing overall energy consumption.
Solution Approach 2:
The system uses periodic calibration pulses interspersed with external measurements. Rather than continuous monitoring, calibration pulses are sent at regular intervals to check and adjust gain, allowing the system to maintain precision while consuming energy only periodically rather than continuously.
3Ease of operation
If the LiDAR sensor operates in extreme temperatures without heat management, then ease of operation is improved, but reliability deteriorates due to gain variations
Solution Approach 1:
The system implements a feedback loop where the processor continuously monitors calibration pulse strength and automatically adjusts the bias voltage to compensate for temperature-induced gain changes. This closed-loop control maintains measurement reliability across extreme temperatures without requiring manual intervention or complex thermal management systems.
Solution Approach 2:
The LiDAR sensor autonomously compensates for temperature effects by using its own internal resources (laser, optical splitter, photodetector, processor) to perform real-time gain calibration and bias voltage adjustment, maintaining reliability without external temperature sensors or manual calibration.
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 enables precise and consistent reflectance measurements across varying temperatures, reducing false detection events and maintaining sensor accuracy without the need for temperature sensing devices.
Implementation Method 1
The LiDAR sensor employs an optical splitter to split the laser pulse into calibration and external pulses
Implementation Method 2
The processor can adjust the bias voltage based on the strength of the calibration pulse, thereby maintaining constant gain without temperature measurement
Implementation Method 3
a laser, a directional sensor, a window, an electromagnetic pulse receiving sensor, and a processor. The laser can be configured to emit a brief and narrow electromagnetic pulse
Implementation Method 4
LiDAR, specifically time-of-flight based LiDAR, is a distance range measurement technique in which a brief laser pulse is emitted and the reflected light is detected while the time between the emitted pulse and reflected pulse is measured
Data Source
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AI summary
A LiDAR can include a laser, an avalanche photodiode, a splitter, and a processor. The laser can be configured to emit a narrow electromagnetic pulse. The avalanche photodiode can be configured to receive one or more electromagnetic pulses and output a response signal in response to said pulses and can also be positioned to receive at least one reflected pulse, reflected by an object external from the LiDAR sensor and caused by the laser. The avalanche photodiode can also have a bias voltage applied to it affecting the response signal. The splitter can be positioned to receive the narrow electromagnetic pulse and split it into at least one external pulse directed toward the object external from the LiDAR sensor and at least one calibration pulse directed toward the photodiode. Further, the processor can be configured to adjust the bias voltage.