MIMO LiDAR System Using Overlapping Fields of View
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Solution Overview
Problem
Conventional LiDAR systems face limitations in resolution, size, cost, and power consumption, particularly in applications like autonomous driving, due to the need for multiple lasers and detectors and mechanical scanning, which can be cumbersome and unreliable.
Innovation Solution
The development of Multiple-Input, Multiple-Output (MIMO) LiDAR systems that use fewer optical components with wider, overlapping fields of view, allowing a single illuminator to illuminate multiple targets and a single detector to detect reflections from multiple illuminators, utilizing pulse sequences with low cross-correlation to distinguish between signals, and employing processors to estimate target positions in three-dimensional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LiDAR systems use multiple lasers and detectors with narrow beams to achieve high resolution, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple laser beams and detector fields of view into overlapping volumetric regions. Multiple illuminators illuminate the same volume of space simultaneously, and multiple detectors detect reflections from the same volume, allowing a single detector to receive signals from multiple illuminators and a single illuminator to illuminate multiple targets within its field of view.
Solution Approach 2:
Each detector is designed to detect reflections from multiple illuminators simultaneously, and each illuminator illuminates multiple targets within its field of view. This multi-functionality reduces the total number of components needed while maintaining the ability to resolve target positions through signal processing.
2Device complexity
If mechanical scanning is used to reduce the number of lasers and detectors, then device complexity is reduced, but reliability decreases due to moving components
Solution Approach 1:
The patent replaces mechanical scanning systems with a stationary array of illuminators and detectors. Instead of mechanically moving a single laser and detector to scan the environment, the system uses multiple fixed illuminators and detectors that simultaneously cover the same volumetric region, eliminating moving parts while maintaining scanning capability.
3Measurement precision
If flash LiDAR systems use a large number of optical detectors to unambiguously detect reflection angles, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the fields of view of multiple detectors to cover overlapping volumetric regions. By having detectors with wider, overlapping fields of view, the system can determine target positions through triangulation and signal processing rather than requiring each detector to precisely identify its own reflection angle.
Solution Approach 2:
The patent introduces signal processing algorithms as an intermediary between the detectors and the target position determination. The processor analyzes signals from multiple detectors and illuminators to unambiguously determine target positions, replacing the need for each detector to independently and precisely identify reflection angles.
4Measurement precision
If conventional LiDAR systems use narrow beams emitted in specific directions to avoid interference, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses pulse sequences with specific properties (substantially white and low cross-correlation) emitted at different times to distinguish between signals from different illuminators. This temporal coding allows multiple illuminators to operate simultaneously without interference, replacing the need for precise directional beam control.
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
MIMO LiDAR systems achieve higher resolution with fewer components, eliminating the need for mechanical scanning and reducing size, cost, and power consumption, while maintaining or improving measurement accuracy and reliability.
Implementation Method 1
The time between when the laser emitted a light pulse and the detector detected a reflection provides the round-trip time to the target
Implementation Method 2
Light detection and ranging (LiDAR) systems use optical wavelengths that can provide finer resolution than other types of systems
Data Source
AI summary
Disclosed herein are multiple-input, multiple-output (MIMO) LiDAR systems in which the fields of view of multiple illuminators (e.g., lasers) overlap and/or fields of view of multiple detectors (e.g., photodiodes) overlap. Some embodiments provide for illuminators that transmit substantially white pulse sequences that are substantially uncorrelated with each other so that they can be distinguished from one another when detected by a single detector.