LiDAR Emitter Layout for Higher Echo Peaks at Oblique Incidence
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Solution Overview
Problem
The farthest detection distance of LiDAR is limited by low ground reflectivity and echo signal broadening due to oblique incidence, leading to reduced detection capability.
Innovation Solution
The LiDAR emitter is designed with lasers emitting detection beams through flat light emitting regions, where the size in one direction is greater than the other, reducing longitudinal divergence and enhancing echo peak values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the laser beam is emitted with a large divergence angle to cover a wide area, then the field of view is improved, but the ground equivalent reflectivity decreases due to oblique incidence
Solution Approach 1:
The emitter is divided into multiple independent laser units, each with its own light emitting region. This segmentation allows different lasers to be optimized for different fields of view while maintaining overall system versatility.
Solution Approach 2:
Different laser units are configured with different light emitting region sizes according to their specific field of view requirements. Lasers with larger fields of view have smaller light emitting regions, while lasers with narrower fields of view have larger light emitting regions, optimizing each local component for its specific function.
2Measurement precision
If the amplitude threshold is set high to ensure high signal-to-noise ratio, then the signal quality is improved, but the detection capability to distant ground is reduced due to low echo peak values
Solution Approach 1:
The light emitting region size is changed as a key parameter to affect the beam divergence and echo characteristics. By optimizing this geometric parameter, the system achieves better echo peak values without compromising signal-to-noise ratio.
3Reliability
If the light emitting region size is increased to reduce beam divergence, then the echo peak value is improved, but the field of view is reduced
Solution Approach 1:
The emitter is segmented into multiple laser units, allowing the system to achieve both high echo peak values (through optimized light emitting region sizes) and wide field of view (through multiple units covering different angular ranges) simultaneously.
Solution Approach 2:
Each laser unit is locally optimized with a specific light emitting region size matched to its field of view requirements, allowing the overall system to achieve both high echo peak values and wide coverage without compromise.
4Length of stationary object
If the laser beam is obliquely incident to distant ground, then the detection distance is extended, but the echo signal is broadened and the peak value is reduced
Solution Approach 1:
The light emitting region size parameter is optimized to control beam divergence characteristics, which directly affects how the beam spreads during oblique incidence. This parameter optimization reduces echo broadening at distant angles while maintaining detection capability.
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 design improves detection capability and signal identification, reducing echo broadening and increasing the probability of valid signal detection, thus enhancing LiDAR performance.
Implementation Method 1
a laser of the plurality of lasers is configured to emit a detection beam through a flat light emitting region
Implementation Method 2
Based on the principle of diffuse reflection, the ground equivalent reflectivity neff is very low (neff=n*cosθ, where n is the reflectivity of the ground, and θ is the incidence angle)
Implementation Method 3
a receiver comprising detectors, wherein the detectors are configured to receive echoes formed by reflection of detection beams emitted by the plurality of lasers from an object, and convert the echoes into electrical signals
Data Source
AI summary
An emitter includes a substrate and multiple lasers. The multiple lasers are arranged on the substrate in an array and configured to emit detection beams. At least a laser of the plurality of lasers is configured to emit a detection beam through a flat light emitting region. A size of the flat light emitting region in a first direction is greater than a size in a second direction.