LiDAR Detector Voltage Control for Short-Range Blind Zone Reduction
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Solution Overview
Problem
LiDAR systems with coaxial optical paths experience a short-range blind zone due to detector saturation caused by direct emission of laser into the receiving optical path, leading to reduced detection accuracy and increased blind zones.
Innovation Solution
A method is introduced where the LiDAR controller applies a first working voltage less than or equal to the detector's breakdown voltage for a short period, followed by a second working voltage greater than the breakdown voltage, allowing for the determination of an electrical crosstalk signal and an echo signal based on the detection signal received after the voltage change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the emission optical path and receiving optical path are made coaxial to reduce system size, then the LiDAR structure is simplified and size is reduced, but detector saturation occurs causing short-range blind zone
Solution Approach 1:
The patent applies dynamic voltage adjustment to the detector, switching between a first working voltage (below breakdown voltage) and a second working voltage (above breakdown voltage) based on the detection phase. This dynamic control allows the detector to operate in different modes: during the laser emission period, it uses the first voltage to avoid saturation from direct laser entry, and during the echo detection period, it uses the second voltage to maximize detection sensitivity, thus resolving the contradiction between compact coaxial design and short-range detection reliability
Solution Approach 2:
The patent changes the electrical parameter (working voltage) of the detector as a function of time and detection phase. By adjusting the voltage parameter dynamically, the system optimizes detector performance for different operational requirements: avoiding saturation during laser emission while maximizing gain during echo reception, thereby maintaining detection accuracy in the short-range blind zone despite the coaxial optical path configuration
2Measurement precision
If the detector working voltage is increased to improve detection sensitivity, then the echo signal detection capability is enhanced, but detector saturation occurs reducing the ranging period
Solution Approach 1:
The patent implements periodic switching of the detector's working voltage between two distinct states: a first voltage state during the laser emission period to prevent saturation, and a second voltage state during the echo detection period to maximize sensitivity. This periodic voltage modulation synchronizes with the laser pulse sequence, ensuring the detector is in the optimal state for each phase of the ranging cycle, thus enhancing echo detection sensitivity without permanently reducing the detector's responsive period
Solution Approach 2:
The patent applies a preliminary voltage adjustment before the laser emission reaches the detector. By setting the detector to the first working voltage (below breakdown voltage) during the expected laser emission period, the system proactively prevents saturation from occurring. This preliminary protective measure ensures that when the high-intensity laser pulse arrives, the detector is already in a protected state, maintaining its ability to respond to subsequent echo signals
3Reliability
If the detector is protected from direct laser entry to avoid saturation, then the short-range blind zone is reduced, but electrical crosstalk signal interference increases
Solution Approach 1:
The patent extracts and separately processes the electrical crosstalk signal from the total detector output. By identifying the crosstalk component as a distinct signal element and subtracting it from the combined signal, the system isolates the true echo signal. This extraction approach allows the detector to operate at higher voltages for improved sensitivity while compensating for the crosstalk interference through signal processing, thus maintaining both saturation avoidance and detection accuracy
Solution Approach 2:
The patent employs feedback mechanisms to measure and compensate for the electrical crosstalk signal. By monitoring the detector output during known non-echo periods and characterizing the crosstalk behavior, the system generates a compensation signal that is subtracted from the total output during echo detection. This feedback-based cancellation allows the use of higher detector voltages without being limited by crosstalk interference, maintaining reliability while enabling improved sensitivity
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 reduces the duration of non-ranging periods due to detector saturation, minimizes the short-range blind zone, and improves the accuracy of the echo signal without degrading the signal-to-noise ratio.
Implementation Method 1
a detector configured to receive an optical signal
Data Source
AI summary
A method for LiDAR detection includes: controlling a laser of a LIDAR to emit a detection beam at a first time point; applying a first working voltage to a detector of the LiDAR from the first time point to a second time point, wherein a magnitude of the first working voltage is less than or equal to a breakdown voltage of the detector; applying a second working voltage to the detector after the second time point, wherein a magnitude of the second working voltage is greater than the breakdown voltage of the detector; determining an electrical crosstalk signal of the detector; and determining an echo signal of the detection beam reflected by an object based on a detection signal received by the detector after the second time point and the electrical crosstalk signal.