FMCW Laser Radar Multi-Beam Scanning for Dense Point Clouds
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Solution Overview
Problem
Current vehicle-mounted FMCW laser radars face challenges in achieving centimeter-level distance resolution and high point cloud density due to the requirement of a frequency modulation bandwidth of more than 10 GHz, resulting in low point cloud density and image definition.
Innovation Solution
The laser radar employs N laser beams split into first and second beams, with adjusted included angles greater than 0 degrees and not exceeding the angular resolution, and uses frequency-modulated continuous waves (FMCWs) with different modulation rates to reduce crosstalk and enhance anti-interference capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency modulation bandwidth is increased to more than 10 GHz to achieve centimeter-level distance resolution, then the measurement precision is improved, but the frequency modulation time increases to above sub-millisecond, resulting in low productivity
Solution Approach 1:
The patent divides a single high-bandwidth detection task into multiple parallel lower-bandwidth detection channels. By using N beam splitting modules to create N detection beams with different angles, each beam operates at a lower modulation bandwidth while collectively achieving the required overall detection resolution and coverage.
Solution Approach 2:
The patent transitions from a single-beam detection approach to a multi-beam spatial detection approach. By introducing angular separation as an additional dimension, the system achieves both high distance resolution and fast scanning speed through spatial diversity rather than temporal sequencing alone.
2Measurement precision
If the frequency modulation bandwidth is increased to more than 10 GHz to achieve centimeter-level distance resolution, then the measurement precision is improved, but the time required to scan one target point increases to more than 10^-4 seconds, resulting in low image definition
Solution Approach 1:
The detection task is segmented into N parallel channels, each handling a portion of the total detection burden. This allows simultaneous acquisition of multiple measurement points, reducing the total time required to scan all points and improve frame rate and image definition.
Solution Approach 2:
The patent enables continuous parallel detection across multiple angular positions simultaneously. Instead of sequentially scanning points one by one, the system performs continuous detection across N different angles at the same time, eliminating idle time and improving overall detection efficiency.
3Quantity of substance
If multiple laser beams with small included angles are used to increase association information, then the point cloud density is improved, but the crosstalk between adjacent beams increases, worsening the reliability
Solution Approach 1:
The patent applies different local characteristics to different beams through individual beam splitting modules. Each module can independently adjust parameters such as modulation frequency or timing for its specific beam, allowing optimized performance for each angular position while minimizing interference from adjacent beams.
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 increases the amount of association information obtained in one detection process, improving point cloud density and image definition by determining association information based on multiple echo signals and first laser beams.
Implementation Method 1
The laser is configured to emit N laser beams, and transmit the N laser beams to the N first beam splitting modules
Implementation Method 2
perform frequency mixing on the received first laser beam and the received echo signal to obtain a beat frequency signal
Data Source
AI summary
A laser radar, which may be applied to autonomous driving and internet of vehicles, includes: a laser: emit N laser beams, and transmit the beams to N first beam splitting modules; first beam splitting module: split the received laser beam into a first laser beam and a second laser beam; an included angle adjustment module: receive N second laser beams, adjust an included angle between any two adjacent second laser beams in the N second laser beams to be greater than 0 degrees and not greater than an angular resolution; a scanning module: receive the N second laser beams, respectively emit the N second laser beams to a detection area at different detection angles; a detection module: receive the first laser beam and a corresponding echo signal, perform frequency mixing to obtain a beat frequency signal, determine association information of a target object based on the beat frequency signal.