Polygon-Scanner LiDAR for Long-Range Range and Velocity Sensing
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Solution Overview
Problem
Conventional LIDAR systems face limitations in accurately determining range and velocity, especially at long distances and in environments with low reflectivity objects, due to limited field of view and interference issues, which affect their performance in autonomous vehicle applications such as commercial trucking.
Innovation Solution
A LIDAR system utilizing a polygon scanner with varying facet lengths and angles, allowing for increased sampling density and improved signal-to-noise ratio, enables the system to effectively detect objects at greater distances and velocities by using frequency or phase modulation, and filtering out interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LIDAR systems use uniform polygon scanner facets, then the system structure is simple, but the field of view coverage and sampling density are limited
Solution Approach 1:
The polygon scanner is divided into multiple facets with different lengths and angles, where each facet is responsible for scanning a specific angular sector. This segmentation allows different regions of the field of view to be covered with appropriate sampling density, improving overall measurement precision without requiring a uniformly complex structure throughout.
Solution Approach 2:
Different facets are designed with locally optimized properties: longer facets with larger angles are used in regions requiring broader coverage, while shorter facets with smaller angles provide higher sampling density in critical areas. This local quality approach resolves the contradiction by making the structure complex only where necessary for improved measurement accuracy.
2Area of stationary object
If polygon scanner facets have large angles, then the field of view coverage is increased, but the sampling density decreases
Solution Approach 1:
The field of view is segmented into multiple angular sectors, each handled by a separate facet. By dividing the total coverage area into discrete segments, the system can use larger facet angles for broad coverage while maintaining adequate sampling density within each segment, thus resolving the trade-off between coverage area and sampling density.
Solution Approach 2:
The system transitions from a single-dimensional approach (uniform facet size) to a two-dimensional optimization space by varying both facet length and angle independently. This allows the design to achieve both large field of view coverage and sufficient sampling density by optimizing the combination of angular and linear dimensions across different facets.
3Measurement precision
If polygon scanner facets have small angles, then the sampling density is increased, but the field of view coverage is reduced
Solution Approach 1:
Multiple facets with small angles are merged together in a sequential arrangement to achieve both high sampling density and extensive field of view coverage. Each facet contributes to the overall coverage while maintaining high sampling density in its local region, and the combination of all facets provides both dense sampling and broad coverage simultaneously.
4Speed
If the LIDAR system uses higher power laser beams, then the detection range is extended, but interference and noise increase
Solution Approach 1:
The LIDAR system uses periodic modulation of the laser beam (frequency or phase modulation) to encode the transmitted signal. This periodic action allows the receiver to distinguish the desired signal from random noise and interference through correlation detection, thereby extending effective detection range without proportionally increasing interference levels.
Solution Approach 2:
The system employs feedback mechanisms where the received signal is compared against the known modulated transmission pattern. This feedback approach enables the system to reject uncorrelated noise and interference while amplifying the correlated return signal, effectively extending detection range without linearly increasing harmful interference.
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 system enhances the accuracy of range and velocity determination, enabling safer and more efficient autonomous vehicle operations by improving detection capabilities beyond conventional LIDAR systems, particularly in long-range applications like commercial trucking.
Implementation Method 1
The polygon scanner includes a plurality of facets. Each facet of the plurality of facets is configured to transmit a second beam responsive to the first beam.
Implementation Method 2
enables the system to effectively detect objects at greater distances and velocities by using frequency or phase modulation
Implementation Method 3
Optical detection of range using lasers, often referenced by a mnemonic, LIDAR, for light detection and ranging
Implementation Method 4
The one or more processors are configured to determine at least one of a range to or a velocity of an object using a return beam received responsive to the transmit beam
Data Source
AI summary
A LIDAR system includes a laser source configured to output a first beam and a polygon scanner. The polygon scanner includes a plurality of facets. Each facet of the plurality of facets is configured to transmit a second beam responsive to the first beam. The plurality of facets include a first facet having a first field of view over which the first facet transmits the second beam and a second facet having a second field of view over which the second facet transmits the second beam. The first field of view is greater than the second field of view.