LiDAR Receiver Bias Control for Glare Noise Detection
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Solution Overview
Problem
The high sensitivity of single photon avalanche diodes (SPADs) in LiDAR systems to ambient light leads to increased average working current, temperature rise, and potential target detection failure due to glare noise, which affects the accuracy of laser beam ranging.
Innovation Solution
Implementing a receiving sensor and a reference sensor in parallel, with a cancellation and transimpedance amplifier circuit to detect glare noise, adjust bias voltage, and reduce noise excitation, thereby improving ranging accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bias voltage of the photodetector is increased to improve photoelectric detection capability, then the sensitivity to ambient light increases, but the average working current increases causing temperature rise and detection failure
Solution Approach 1:
The patent applies preliminary anti-action by detecting the presence of glare noise before it causes harmful effects. The processing circuit detects glare noise in the received light signal and proactively adjusts the bias voltage to a lower level when glare is detected, preventing the temperature rise and detection failure that would otherwise occur from operating at high bias voltage in the presence of strong ambient light
Solution Approach 2:
The patent implements dynamics by making the bias voltage adjustable rather than fixed. The bias voltage is dynamically changed based on the detection results: when glare noise is detected, the bias voltage is reduced to prevent overheating; when no glare is present, the bias voltage can be maintained at a higher level for optimal detection capability. This dynamic adjustment resolves the contradiction between maintaining high detection capability and preventing temperature-related failures
2Reliability
If the bias voltage is reduced to reduce average working current and temperature rise, then the photoelectric detection capability decreases, but the sensitivity to ambient light is reduced
Solution Approach 1:
The patent uses dynamic bias voltage adjustment to resolve this contradiction. Instead of operating continuously at a reduced bias voltage, the system dynamically switches between high and low bias voltage levels based on ambient light conditions. When glare is detected, the bias voltage is reduced to maintain reliability; when glare is absent, the bias voltage is increased to maintain optimal detection capability, thus resolving the trade-off between reliability and measurement precision
3Measurement precision
If a reference sensor is added to detect and compensate for stray light, then the ability to identify glare noise improves, but the device complexity increases
Solution Approach 1:
The patent applies merging by integrating the reference sensor and its processing circuit directly into the existing receiving end structure. The reference sensor is positioned adjacent to the main photodetector, and the processing circuit that detects glare noise and controls bias voltage adjustment is merged with the signal processing path of the main detector. This integrated approach improves glare noise identification while minimizing the increase in device complexity compared to a separate standalone compensation system
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
The proposed solution effectively reduces glare noise influence by detecting and adjusting bias voltage, enhancing the accuracy and reliability of LiDAR systems in various lighting conditions.
Implementation Method 1
a receiving sensor and a reference sensor in a shading state are arranged in parallel at the receiving end... acquire a first current signal output by the receiving sensor and a second current signal output by the reference sensor
Implementation Method 2
arranged in parallel at the receiving end... with a cancellation and transimpedance amplifier circuit to detect glare noise, adjust bias voltage, and reduce noise excitation
Data Source
Figure 1~2a
Figure 2b~2d
Figure 3~4
AI summary
A method and apparatus for improving laser beam ranging capability of a LiDAR system and a storage medium are provided. The method includes: acquiring a first current signal output by a receiving sensor and a second current signal output by a reference sensor; determining a cancellation residue based on the first current signal and the second current signal; determining whether glare noise exists in echo light based on the cancellation residues; and adjusting a bias voltage at a receiving end of the LiDAR system in a case that the glare noise exists in the echo light. Therefore, in the embodiment of the present application, whether glare noise exists in the echo light can be detected by arranging the receiving sensor and the reference sensor at the receiving end of the LiDAR system, and if yes, the bias voltage at the receiving end is reduced to reduce the average current of the receiving sensor and reduce noise excitation, so that the accuracy of the ranging capability of the LiDAR system is improved.