Array-Based LiDAR Axis Layout for Crosstalk Reduction
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Solution Overview
Problem
Current LiDAR systems face significant interference issues due to crosstalk among multiple units operating at the same wavelength, particularly in applications like autonomous vehicle navigation, which affects distance measurements and signal intensity, and existing solutions like time division synchronization lower capture rates and are impractical for integrated systems.
Innovation Solution
The use of an array of emitter/detector sets with unique on-coincident axis configurations and multi-bit emitter sequences reduces interference by ensuring each emitter/detector pair has a distinct axis, eliminating the need for synchronization with other units and allowing simultaneous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LiDAR units operate at the same wavelength simultaneously, then the productivity and coverage of the system is improved, but crosstalk interference increases causing measurement errors
Solution Approach 1:
The patent segments the electromagnetic spectrum by assigning different wavelength channels to different LiDAR units. Each unit operates on a unique wavelength, allowing simultaneous operation without crosstalk. This spectral segmentation enables multiple units to coexist while maintaining measurement accuracy.
Solution Approach 2:
Each LiDAR unit is configured with specific optical properties (wavelength, field of view, detection range) tailored to its operational requirements. This local optimization allows each unit to operate independently at its optimal parameters while minimizing interference with other units.
2Reliability
If time division synchronization is used to reduce crosstalk, then interference among units is reduced, but capture rate decreases and system complexity increases
Solution Approach 1:
The patent employs periodic pulsed emission at different wavelengths rather than time-division multiplexing. Each unit emits periodic pulses at its assigned wavelength simultaneously with other units, eliminating the need for synchronization while maintaining high capture rates.
Solution Approach 2:
The system changes the wavelength parameter for each LiDAR unit to enable simultaneous operation. By operating in the wavelength domain rather than the time domain, the system achieves both high capture rates and effective crosstalk reduction.
3Adaptability or versatility
If multiple LiDAR units are deployed for autonomous vehicle navigation, then the field of view and detection capability are improved, but interference from other units increases
Solution Approach 1:
The patent adds the wavelength dimension to differentiate between multiple LiDAR units. Instead of competing in the same spatial and temporal domain, units operate in different spectral dimensions, enabling enhanced detection capability without increased interference.
Solution Approach 2:
The patent introduces wavelength as an intermediary parameter that mediates between multiple LiDAR units. By using wavelength as a distinguishing characteristic, the system enables multiple units to operate simultaneously without direct interference, effectively managing the harmful crosstalk factor.
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 significantly reduces interference among emitters and other devices, enhancing precision and capture rates while enabling reliable operation in environments with numerous simultaneously operating LiDAR units.
Implementation Method 1
process time of flight information for that received light energy
Implementation Method 2
configured to receive reflected light energy
Data Source
AI summary
An array-based light detection and ranging (LiDAR) unit includes an array of emitter/detector sets configured to cover a field of view for the unit. Each emitter/detector set emits and receives light energy on a specific coincident axis unique for that emitter/detector set. A control system coupled to the array of emitter/detector sets controls initiation of light energy from each emitter and processes time of flight information for light energy received on the coincident axis by the corresponding detector for the emitter/detector set. The time of flight information provides imaging information corresponding to the field of view. Interference among light energy is reduced with respect to detectors in the LiDAR unit not corresponding to the specific coincident axis, and with respect to other LiDAR units and ambient sources of light energy. In one embodiment, multiple array-based LiDAR units are used as part of a control system for an autonomous vehicle.