Broadband Lidar Using Angular Dispersion for 360-Degree Detection

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Solution Overview

Problem

Current lidar systems for 360° environment detection in motor vehicles are complex, expensive, and prone to mechanical failures, requiring multiple sensors with overlapping fields of view and complex data synchronization, which limits their reliability and installation options.

Innovation Solution

A method using broadband laser pulses with angular dispersion to generate fan pulses, allowing for precise distance and width determination of objects through time-of-flight and spectral analysis, utilizing a central light source and distributed emitters with optical fibers and dispersive elements, eliminating the need for mechanical deflection devices and enabling concealed installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple individual sensors are used for 360° environment detection, then the field of view coverage is improved, but the device complexity and spatial dimensions increase

Engineering Contradiction:
Improvefield of view coverageVSAvoidsensor system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple sensor functions into a single integrated lidar unit that can perform 360° environment detection without requiring multiple separate sensors. This merging approach reduces device complexity while maintaining comprehensive field of view coverage through the use of a single light source and detector assembly with optimized optical paths.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lidar sensor is designed with multi-functional capabilities to perform various detection tasks (distance measurement, object classification, 3D mapping) using a single sensor unit. This universal design eliminates the need for multiple specialized sensors, reducing both device complexity and spatial requirements while maintaining comprehensive environmental awareness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Area of stationary object

If mechanical deflection devices are used for laser pivoting, then the field of view scanning capability is improved, but the reliability deteriorates due to mechanical failures

Engineering Contradiction:
Improvescanning field of viewVSAvoidmechanical failure rate
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent replaces mechanical deflection devices with non-mechanical alternatives such as electro-optic modulators or acousto-optic deflectors that can change the direction of laser beams without moving parts. This substitution eliminates mechanical wear and failure modes while maintaining the ability to scan and cover the required field of view for comprehensive environment detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system employs dynamic optical control methods where the laser beam direction is changed electronically rather than mechanically. This allows for rapid, precise scanning of the environment without the reliability issues associated with mechanical pivoting, while still achieving complete 360° coverage through coordinated control of multiple laser sources or beam steering elements.

Inventive Principle:
Principle #15Dynamics

3Area of stationary object

If many individual sensors with overlapping fields of view are combined, then the detection coverage is improved, but the data processing complexity and synchronization requirements increase

Engineering Contradiction:
Improvedetection coverageVSAvoiddata processing complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges multiple detection functions into a single sensor unit that inherently provides overlapping field of view coverage through its optical design. This eliminates the need for complex data fusion algorithms required when combining multiple independent sensors, as the single sensor naturally captures comprehensive spatial information with inherent temporal synchronization.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single lidar sensor is designed with multiple detection channels or sub-apertures that independently capture different spatial regions with overlapping fields of view. Each channel processes its own data stream independently, simplifying synchronization requirements compared to merging data from multiple separate sensors, while still achieving comprehensive 360° detection coverage through the combined output of all channels.

Inventive Principle:
Principle #1Segmentation

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 simplifies and robustly detects objects in a 360° field using fewer, smaller sensors with reduced mechanical complexity, improved reliability, and cost-effectiveness, allowing for concealed installation in vehicles, enhancing safety and reducing the complexity of data fusion and synchronization.

Implementation Method 1

generating a fan pulse that illuminates a specified angle by spectrally splitting the broadband laser pulse by applying an angular dispersion to the broadband laser pulse, as a result of which the different wavelengths of the wavelength range of the broadband laser pulse are fanned out into different angles

Methodology Applied
Scientific EffectAngular dispersion: Dispersion (of waves)

Implementation Method 2

determination of the propagation time of the fan pulse from the dispersive element to the object using a time-of-Flight method

Methodology Applied
Scientific EffectTime-of-flight: Time of Flight

Data Source

PatentEP3579015B1Method and device for detecting an object by broadband laser pulses
Publication Date: 2023.03.29 VOLKSWAGEN AG
  • EP3579015B1 patent drawingFigure 1
  • EP3579015B1 patent drawingFigure 2
  • EP3579015B1 patent drawing

AI summary

A method and apparatus for detecting an object using broadband laser pulses with a predetermined wavelength distribution, pulse duration, and repetition frequency, suitable for use in motor vehicles, comprises the following steps: - Emitting broadband laser pulses, - Generating a fan pulse from each broadband laser pulse by applying an angular dispersion to the broadband laser pulse, thereby fanning out the different wavelengths of the broadband laser pulse at different angles, - Detecting a reflected segment of the fan pulse that is reflected by the object located within the fan pulse, - Determining the wavelengths present in the reflected segment of the fan pulse, - Determining the travel time of the fan pulse from the dispersive element to the object using a time-of-flight method.and - determining the distance and width of the object as a function of the travel time of the fan pulse and the wavelength range of the reflected segment of the fan pulse.