Lidar Interference Detection via Signal Combination

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Solution Overview

Problem

LIDAR systems face interference issues due to the increasing deployment of multiple sensors in vehicles, leading to incorrect target detection and potential safety hazards, as existing interference detection and mitigation methods are not yet effectively implemented in automotive LIDAR sensors.

Innovation Solution

A LIDAR sensor system that combines detector signals from multiple light pulses at various delay times to generate a combined signal for interference detection and mitigation, using techniques such as averaging, minimum, or median computation to suppress interference and noise, while exploiting the coherence of target reflections and incoherence of interference in the pulse repetition domain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple LIDAR sensors are deployed in vehicles to improve measurement precision and resolution, then the measurement precision and resolution are improved, but interference between sensors increases leading to incorrect target detection

Engineering Contradiction:

ImproveresolutionVSAvoidinterference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent combines multiple detector signals corresponding to the same delay time from multiple light pulses into a single combined signal. This merging process allows the system to maintain high measurement precision while mitigating interference through signal combination operations such as averaging, minimum computation, or median computation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the harmful interference signals into beneficial information by analyzing the coherence properties of combined signals. Through verification processes that check for consistent delay times across multiple pulses, the system distinguishes between coherent target reflections and incoherent interference, transforming the interference problem into a detection opportunity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If detector signals are combined to mitigate interference, then interference is reduced, but the complexity of signal processing increases

Engineering Contradiction:

ImproveinterferenceVSAvoidsignal processing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the signal processing into distinct stages: signal combination, verification, and interference detection. By dividing the complex processing task into manageable segments with specific functions, the system reduces overall complexity while maintaining effective interference mitigation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the processing approach by applying different combination operations (averaging, minimum, median) and verification criteria based on the specific interference scenario. This parameter-based flexibility allows the system to adapt to different conditions without requiring completely different processing architectures.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If verification of target reflections is performed to improve detection accuracy, then false positives are reduced, but processing time increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary combination of detector signals before full verification processing. By pre-processing signals through combination operations that already provide some interference mitigation, the system reduces the burden on subsequent verification steps, thereby decreasing overall processing time while maintaining detection accuracy.

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

Effectively detects and mitigates interference, improving the accuracy of target detection and reducing false positives, thereby enhancing the reliability of LIDAR systems in automotive applications.

Implementation Method 1

LIDAR refers to a surveying concept that measures distance to a target by illuminating the target with pulsed laser light and measuring the reflected pulses with a light sensitive sensor

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

the range from the light source to the target can be determined based on the time-of-flight (ToF) of the light beam from the source to the sensor

Methodology Applied

Scientific EffectTime-of-flight measurement: Time of Flight

Data Source

PatentUS11415671B2Interference detection and mitigation for lidar systems

Publication Date: 2022.08.16 INFINEON TECHNOLOGIES AG

AI summary

The present disclosure relates to a light detection and ranging (LIDAR) sensor comprising a detector configured to generate a first detector signal at a first delay time following an emission of a first light pulse and to generate at least one second detector signal at the first delay time following an emission of at least a second light pulse; and a processor configured to generate a combined signal for the first delay time based on a combination of the first detector signal and the at least one second detector signal. Depending on the type of combination, the combined signal can be used for interference detection or mitigation.