Lidar Signal Receiving Circuit Dynamic Gain Control
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Solution Overview
Problem
Traditional Lidar systems face challenges in accurately measuring long-distance optical signals due to signal saturation and under-compensation, leading to inaccurate ranging and reflection information, as they operate in a non-linear region with high dynamic signal fluctuations.
Innovation Solution
A Lidar signal receiving circuit with a variable-gain amplifier and a controller that adjusts the gain based on the ranging distance, ensuring a stable signal amplitude by compensating for changes in the photocurrent signal, thereby improving the dynamic range and ranging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-power lasers are used in traditional Lidar, then the system structure is simple, but the signal becomes saturated for close-range targets and too weak for long-distance targets
Solution Approach 1:
The patent implements dynamic gain adjustment in the signal receiving circuit based on detected signal strength. The system automatically switches between different gain levels (first gain for strong signals, second gain for weak signals) to adapt to varying target distances, resolving the contradiction between simple structure and measurement precision
Solution Approach 2:
The patent changes the amplification parameter (gain) of the receiving circuit based on signal conditions. By adjusting the gain parameter dynamically, the system can handle both strong signals from close targets and weak signals from distant targets, improving measurement precision without significantly increasing system complexity
2Length of stationary object
If high-power lasers are used to increase reflected optical signal intensity, then long-distance ranging capability is improved, but close-range signals become overly powerful and saturated
Solution Approach 1:
The patent uses dynamic gain control to adjust the amplification level based on signal strength. When close-range targets are detected, the system reduces gain to prevent saturation; when long-distance targets are detected, the system increases gain to enhance weak signals, thus resolving the contradiction between ranging distance and signal saturation
Solution Approach 2:
The patent implements a feedback mechanism where the signal strength is continuously monitored and used to adjust the gain level. This closed-loop control prevents signal saturation by reducing gain when signals are strong while maintaining sensitivity for weak long-distance signals
3Adaptability or versatility
If the reflected optical signal energy fluctuates in high dynamic range, then the system can detect various distances and reflectivities, but the electrical signal becomes saturated or under-compensated after amplification
Solution Approach 1:
The patent dynamically adjusts the gain level based on the detected signal amplitude. For strong signals (close-range or high reflectivity), the system uses a first gain level to prevent saturation; for weak signals (long-distance or low reflectivity), the system uses a second gain level to ensure adequate amplification, thus maintaining signal accuracy across high dynamic range conditions
Solution Approach 2:
The patent segments the amplification process into multiple gain levels. By dividing the single amplification stage into conditional stages (first gain for strong signals, second gain for weak signals), the system can handle the full dynamic range while maintaining signal accuracy and preventing saturation or under-compensation
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 enhances the Lidar's dynamic range and ranging capability, reducing signal saturation and under-compensation issues, resulting in more accurate distance and reflection information measurements.
Implementation Method 1
an optical signal processing circuit (B10) to receive the reflected optical signal and convert the reflected optical signal into photocurrent signal
Data Source
AI summary
The present application discloses an optical signal processing circuit for a Lidar. The optical signal processing circuit includes an optical processing circuit, a gain control circuit connected to the optical processing circuit, and a controller connected to the gain control circuit. The optical processing circuit includes an optical sensor and an amplification circuit. The optical sensor is configured to convert an optical signal to a photocurrent signal, and the amplification circuit is configured to convert and amplify the photocurrent signal to a voltage signal. The controller adjusts a gain of the optical processing circuit via the gain control circuit and based on an amplitude of the voltage signal.