Lidar Control Unit Dynamic Mode Switching

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Solution Overview

Problem

Lidar systems for autonomous driving and advanced driver assistance systems face limitations in dynamic range, leading to poor signal quality and insufficient spatial resolution at different distances, particularly when detecting fast-moving objects and objects with varying contrast.

Innovation Solution

A lidar system with a control unit that adjusts the power of laser pulses and detector sensitivity to operate in multiple predefined modes, allowing for improved dynamic range by distinguishing between high and low reflectivity objects, thereby preventing detector saturation and enhancing measurement stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the detector gain is increased to detect low-reflectivity objects at a distance, then the detection capability for distant objects is improved, but the detector becomes saturated by high-reflectivity objects close by

Engineering Contradiction:
Improvedetection capability for distant objectsVSAvoiddetector saturation from high-reflectivity objects
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the detector gain adjustable and controllable based on operating mode. The control unit dynamically switches between a first operating mode (higher gain for distant low-reflectivity objects) and a second operating mode (lower gain to prevent saturation from close high-reflectivity objects), allowing the system to adapt to different measurement scenarios and resolve the contradiction between detecting distant objects and avoiding saturation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detector gain parameter based on the selected operating mode. By controlling the detector to operate at different gain levels (first gain value for distant objects, second gain value for close objects), the system can optimize measurement precision for different ranges while preventing harmful saturation effects, thus resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the laser power is increased to improve signal quality for distant objects, then the signal-to-noise ratio is improved, but the return signal from close objects causes detector saturation

Engineering Contradiction:
Improvesignal quality for distant objectsVSAvoiddetector saturation from close objects
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the laser power controllable and switchable between operating modes. The control unit adjusts the laser power level based on the measurement scenario - using higher power for distant objects to improve signal quality while using lower power for close objects to prevent detector saturation, thus resolving the contradiction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the laser power parameter based on the selected operating mode. By controlling the laser to emit at different power levels (first power level for distant objects, second power level for close objects), the system optimizes the signal-to-noise ratio for distant detection while preventing harmful saturation from close high-reflectivity objects.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If auto gain adjustment is used to adapt to different distances, then the dynamic range is improved, but the response to fast-moving objects and fast contrast changes is delayed

Engineering Contradiction:
Improvedynamic rangeVSAvoidresponse speed to fast-moving objects
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent applies preliminary action by pre-defining multiple operating modes with predetermined detector gain and laser power settings for different measurement scenarios (distant low-reflectivity objects vs. close high-reflectivity objects). Instead of dynamically adjusting parameters in real-time during measurement, the system pre-configures appropriate settings and switches between them, eliminating the delay associated with real-time auto-gain adjustment while maintaining adaptability to different distances and object types.

Inventive Principle:
Principle #10Preliminary action

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 effectively increases dynamic range, enabling the detection of low-reflectivity objects at a distance while preventing saturation from high-reflectivity objects close by, resulting in improved data quality and more predictable behavior for autonomous driving applications.

Implementation Method 1

at least one laser source configured to emit laser pulses

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

at least one detector configured to detect reflections of said laser pulses

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a control unit configured to perform time-of-flight measurements on said laser pulses and the detected reflections

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP4303615A1Lidar system and method to operate
Publication Date: 2024.01.10 MAGNA ELECTRONICS SWEDEN AB
  • EP4303615A1 patent drawingFigure 1~2
  • EP4303615A1 patent drawingFigure 3~6
  • EP4303615A1 patent drawingFigure 7~9

AI summary

The invention relates to a lidar system (10) comprising at least one laser source (11) configured to emit laser pulses (15) and to direct said laser pulses (15) in a field of view (16), at least one detector (13) configured to detect reflections (17) of said laser pulses (15), and a control unit (14) configured to perform time-of-flight measurements on said laser pulses (15) and the detected reflections (17). The control unit (14) is configured to control the power of the laser pulses (15) of the at least one laser source (11) and/or the sensitivity of the at least one detector (13), wherein the control unit (14) is configured to control the at least one laser source (11) and/or the at least one detector (13) to perform measurements with at least two different operating modes, wherein in a first operating mode the at least one detector (13) has a predefined sensitivity and/or the at least one laser source (11) is set to a predefined power of the laser pulses (15), wherein in a second operating mode the at least one detector (13) has a higher sensitivity and/or the at least one laser source (11) is set to higher power of the laser pulses (15) than in the first operating mode, wherein said measurements with different operating modes are performed in a predefined time period.