Laser Receiving System Stray Light Suppression
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Solution Overview
Problem
LiDAR systems using single-photon receivers face instability and accuracy issues due to stray light interference, leading to blind spots in short-distance detection and signal saturation at longer distances.
Innovation Solution
A laser receiving system comprising a receiver, transimpedance amplification circuit, and measurement circuits that distinguish and separate stray light signals from detection echo signals through pulse width compression, ensuring accurate identification and sampling of echo signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-photon receiver is used to improve photoelectric conversion capability, then ranging capability is improved, but stray light interference causes receiver operation instability and ranging accuracy degradation
Solution Approach 1:
The patent divides the detection process into multiple time segments (first detection period and second detection period) with different laser powers. By segmenting the detection into short-distance and long-distance modes, the system can selectively activate appropriate detection circuits for different ranges, reducing stray light interference in each segment while maintaining overall detection capability.
Solution Approach 2:
The patent dynamically adjusts the laser emission power based on detection distance requirements. The system switches between high power (for long-distance detection) and low power (for short-distance detection) modes, making the detection process adaptive to different scenarios and reducing unnecessary stray light generation.
2Length of moving object
If high power laser pulse is used to extend detection distance, then ranging coverage is improved, but stray light signal saturation occurs causing short-distance detection blind spots
Solution Approach 1:
The patent segments the detection range into short-distance and long-distance zones, using different laser powers for each zone. A first detection circuit with lower power handles short-distance detection to avoid saturation, while a second detection circuit with higher power handles long-distance detection, eliminating blind spots.
Solution Approach 2:
The patent applies different detection characteristics to different spatial zones. The first detection circuit is optimized for short-distance detection with lower gain, while the second detection circuit is optimized for long-distance detection with higher gain, matching local detection requirements to avoid signal saturation in near-field while maintaining sensitivity in far-field.
3Power
If laser power is increased to improve signal strength, then detection sensitivity is improved, but stray light interference intensity increases causing signal distortion
Solution Approach 1:
The patent dynamically adjusts laser power based on detection distance and target reflectivity characteristics. The system uses high power only when long-distance detection is required, and switches to low power for short-distance detection, making the stray light generation dynamic and necessary rather than constant and harmful.
Solution Approach 2:
The patent changes the laser power parameter according to detection requirements, using two distinct power levels (high and low) to optimize the signal-to-stray-light ratio for different detection scenarios, thereby improving overall system performance while minimizing harmful stray light effects.
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 solution effectively reduces the impact of stray light, eliminating blind spots for short-distance detection and maintaining ranging stability and accuracy across varying distances, enabling full-coverage ranging without signal distortion.
Implementation Method 1
A receiver based on a single-photon principle has excellent photoelectric conversion capability
Implementation Method 2
the transimpedance amplification circuit is configured to perform transimpedance amplification on the echo signal
Implementation Method 3
After shaping, a pulse width of the echo signal is compressed, the stray light signal and the detection echo signal are both shaped into rapid-recovering signals
Data Source
AI summary
This application provides a laser receiving system, which includes a receiver, a transimpedance amplification circuit, and at least one measurement circuit. The at least one measurement circuit includes a first measurement circuit, where the receiver is connected to a terminal of the transimpedance amplification circuit, and is configured to receive an echo laser beam and output an echo signal. The transimpedance amplification circuit has a terminal connected to the receiver and another terminal separately connected to each of the at least one measurement circuit, and is configured to perform transimpedance amplification on the echo signal. The first measurement circuit is configured to output a sampling signal after shaping the echo signal.