Multibeam LiDAR Scanner With Pulse Coding to Reduce Cross-Talk
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Solution Overview
Problem
Existing LiDAR modules for autonomous vehicles require improved scanning capabilities with a horizontal field-of-view (HFOV) of 80°, vertical field-of-view (VFOV) of ±25°, and high frame rates to effectively map roads, while minimizing crosstalk and optical cross-talk between multiple beams.
Innovation Solution
A laser scanner device with a LiDAR module using a multibeam transmitter and a receiver with a common exit optics, generating multiple measuring beams and employing holographic structures, polarization states, and pulse coding to achieve a HFOV of 60°-180°, iVFOV of ±2°-±5°, and a frame rate of at least 10-25Hz, while reducing optical cross-talk through beam alignment and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple measuring beams are generated to increase scanning coverage and frame rate, then productivity and scanning speed are improved, but optical cross-talk between beams increases causing measurement errors
Solution Approach 1:
The patent applies preliminary action by pre-coding each measuring beam with a unique identification code before transmission. This allows the receiver to identify and separate individual beam returns even when they arrive simultaneously or overlap in time, preventing cross-talk errors and enabling accurate measurement with multiple beams operating in parallel
Solution Approach 2:
The patent uses pulse coding as an optical signal differentiation method, where each measuring beam is assigned a unique temporal code pattern. This allows the receiver to distinguish between different beams by their code signatures, effectively separating overlapping signals and eliminating cross-contamination between adjacent beams
2Adaptability or versatility
If the horizontal field-of-view is increased to 80° for comprehensive road mapping, then adaptability and coverage area are improved, but device complexity increases requiring more deflection elements
Solution Approach 1:
The patent merges the functions of multiple deflection elements into a single integrated deflecting unit that can steer multiple measuring beams simultaneously across a wide horizontal field-of-view of 80°. This consolidation reduces mechanical complexity while maintaining comprehensive scanning coverage through coordinated beam control
Solution Approach 2:
The patent employs dynamic beam steering where the deflecting unit can independently control the direction and timing of multiple measuring beams in real-time. This dynamic control enables comprehensive 80° horizontal coverage while minimizing mechanical complexity through adaptive, software-controlled beam positioning rather than fixed mechanical structures
3Productivity
If the instantaneous vertical field-of-view is scanned at very high speed to achieve beyond 1 Megapoint per second, then productivity is improved, but measurement precision may be compromised due to reduced sampling time
Solution Approach 1:
The patent applies waveform digitizing technology that continuously samples and digitizes the entire returning pulse waveform at high rates. This continuous digital sampling captures complete amplitude and temporal information even during rapid scanning, maintaining measurement precision while enabling point rates beyond 1 Megapoint per second through efficient digital signal processing
Solution Approach 2:
The patent changes the sampling and detection parameters by using waveform digitizing instead of traditional threshold-based detection. This allows the system to process and accurately measure returning signals at extremely high speeds by digitizing the complete waveform and applying advanced signal processing algorithms, maintaining precision despite reduced sampling time per point
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 enables high point density and accuracy in mapping with reduced mechanical complexity, allowing for compact design and efficient obstacle detection in various driving conditions.
Implementation Method 1
the propagation time of a laser measuring beam is determined
Implementation Method 2
a common exit optics configured for collimating all measuring beams
Implementation Method 3
a deflection element may be present to vary the measuring direction of the laser distance measuring beam
Data Source
Figure 1~2
Figure 3a~3c
Figure 4~5
AI summary
The invention pertains to a laser scanner device (1) adapted to be mounted to a vehicle (2), the device (1) comprising a LiDAR module working based on a laser measuring beam (5,26) and time-of-flight-measurement-principle, in particular using the technology of waveform digitizing. The LiDAR module is configured to provide a horizontal field of view (3) of at least 60°, an instantaneous vertical field of view (17) of at least ± 2°, a scan resolution of at least one point per 0.8° in horizontal and vertical direction, and a frame rate of at least 10 Hz for scanning at least the entire horizontal (3) and instantaneous vertical (17) field of view with said scan resolution, wherein the LiDAR module comprises a multibeam transmitter configured for generating a plurality of measuring beams (5,26), particularly pulsed laser beams, defining a plurality of essentially instantaneous scanning axes (6).