Rotating Navigation Sensor IMU Backup for Dust-Blocked Localization

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Solution Overview

Problem

Existing navigation sensors face challenges in maintaining accurate localization due to temporary failures or malfunctions caused by unfavorable environmental conditions, such as dust, fog, or inadequate lighting, which can obstruct the object detection sensor's field of view.

Innovation Solution

Incorporating an inertial measurement unit (IMU) on the rotating scanning unit to detect accelerations and angular velocities, and a rotational speed sensor to correct these signals, allowing the evaluation unit to determine coordinate data sets based on corrected acceleration and angular velocity signals, thereby compensating for temporary failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an object detection sensor (laser scanner or LIDAR) is used for localization, then localization accuracy is improved, but the system becomes vulnerable to environmental disruptions such as dust, fog, and inadequate lighting

Engineering Contradiction:
Improvelocalization accuracyVSAvoidsystem reliability under environmental conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The navigation sensor is divided into two independent subsystems: an object detection sensor (laser scanner/LIDAR) for primary localization and an inertial measurement unit (IMU) for backup localization. Each subsystem operates independently, and when one fails due to environmental conditions, the other takes over to maintain continuous localization capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system proactively prepares for potential sensor failures by integrating an IMU that can compensate for object detection sensor malfunctions. The evaluation unit continuously monitors the quality of localization data and switches to inertial navigation when environmental conditions (dust, fog, lighting) degrade laser scanner performance, ensuring uninterrupted localization.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a high-precision inertial measurement unit is used to compensate for sensor failures, then reliability is improved, but cost and device complexity increase

Engineering Contradiction:
Improvecontinuous localization capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a cost-effective IMU with limited functionality rather than a high-precision inertial navigation system. The IMU serves as a backup component that activates only when the object detection sensor fails, providing adequate compensation without requiring expensive custom inertial units. This approach maintains reliability while controlling cost and complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The IMU is integrated into the existing navigation sensor structure, sharing the evaluation unit and coordinate system with the object detection sensor. This multi-functional design allows the same hardware platform to perform both laser-based localization and inertial navigation, reducing overall system complexity and avoiding the need for separate dedicated systems.

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

3Ease of manufacture

If the inertial measurement unit is placed on the rotating scanning unit, then cost is reduced by using standard IMUs, but measurement accuracy deteriorates due to rotation-induced accelerations

Engineering Contradiction:
Improvecost-effectivenessVSAvoidacceleration measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system dynamically adapts to the rotating IMU's measurement characteristics by using the evaluation unit to distinguish between rotation-induced accelerations and actual motion signals. The evaluation unit processes IMU data in conjunction with object detection sensor feedback, compensating for centrifugal and Coriolis forces generated by the rotating scanning unit, thereby maintaining measurement accuracy despite the dynamic mounting position.

Inventive Principle:
Principle #15Dynamics

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

Enables cost-effective compensation for environmental disruptions by using low-cost IMUs and MEMS, ensuring continuous localization without the need for costly custom inertial units, and overcoming zero-point suppression issues.

Implementation Method 1

a receiver, which is configured for receiving signals generated by objects present in the monitoring area through the reflection of incident signals

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an inertial measuring unit connected to the evaluation unit is arranged on the scanning unit, which is configured to detect accelerations and/or angular velocities of the rotating scanning unit

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP4632429B1Navigation sensor
Publication Date: 2026.03.18 SICK AG
  • EP4632429B1 patent drawingFigure 1

AI summary

Navigation sensor for determining a coordinate data set, which comprises a spatial position and/or a location and/or a movement of the navigation sensor or of a movable object connected to the navigation sensor in space, with an object detection sensor, which is configured for periodically scanning a surveillance area and comprises a base unit and a scanning unit rotatably mounted on the base unit, wherein the scanning unit has a transmitting device, which is configured for transmitting transmission signals into a surveillance area, and a receiving device, which is configured for receiving reception signals generated by objects present in the surveillance area by remission of incident transmission signals, and for converting the received light signals into electrical reception signals, and an evaluation unit connected to the object detection sensor, which is configured toto determine the coordinate data set at least on the basis of the electrical received signals. According to the invention, at least one inertial measuring unit connected to the evaluation unit is arranged on the scanning unit, which is configured to detect accelerations and/or angular velocities of the rotating scanning unit and to transmit corresponding acceleration signals and/or angular velocity signals to the evaluation unit, and that the evaluation unit is configured to additionally determine the coordinate data set on the basis of the acceleration signals and/or angular velocity signals.