Rotary Table Inertial Sensor Adaptive Rotation

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Solution Overview

Problem

Navigation devices with inertial sensors face high costs due to stringent accuracy requirements, and frequent use of mechanical turntables for reversal measurements leads to wear and tear, reducing precision and lifespan.

Innovation Solution

A navigation device with a rotary table and inertial measurement unit that rotates only when measurement quality falls below a specified threshold, using an evaluation device to determine data quality and trigger rotations, reducing unnecessary wear and maintaining performance by adjusting rotation frequency based on quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the rotary table is rotated frequently at regular intervals for reversal measurements, then measurement precision is improved, but the mechanical parts experience wear and tear reducing device lifespan

Engineering Contradiction:
Improveheading accuracyVSAvoiddevice service life
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The system dynamically adjusts the rotation frequency of the rotary table based on real-time assessment of measurement quality and detected drift. Instead of fixed periodic rotation, the evaluation device continuously monitors inertial measurement unit data and triggers rotation only when drift exceeds a threshold or measurement quality degrades, making the rotation schedule adaptive rather than static

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter of rotation frequency based on measured conditions. The evaluation device assesses measurement quality metrics and drift levels, then adjusts the rotation interval accordingly - rotating more frequently when drift is detected and less frequently when measurements remain stable, optimizing the balance between precision and mechanical wear

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the rotary table is rotated frequently to maintain measurement quality, then navigation accuracy is improved, but power consumption increases

Engineering Contradiction:
Improvenavigation accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The rotation frequency is dynamically adjusted based on real-time measurement quality assessment. The evaluation device monitors inertial sensor data and only triggers rotary table rotation when drift is detected or measurement quality degrades below thresholds, rather than rotating at fixed intervals regardless of actual need

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback loop where the evaluation device continuously assesses measurement quality from the inertial measuring unit, compares it against predefined thresholds, and uses this feedback to control whether rotation should be triggered. This closed-loop control ensures rotation occurs only when necessary to maintain accuracy

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If inexpensive sensors are used to reduce costs, then device cost is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvedevice costVSAvoidsensor accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system replaces reliance on inherently precise but expensive inertial sensors with a computational approach using inexpensive sensors combined with reversal measurement technology. The inertial measuring unit rotates 180 degrees on the rotary table, and measurement errors are compensated through mathematical processing of the reversed measurements, achieving high precision with low-cost MEMS sensors

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

Solution Approach 2:

The rotary table acts as an intermediary mechanism that enables error compensation. By physically reversing the orientation of inexpensive inertial sensors through precise 180-degree rotation, the system creates opposing measurement sets that can be mathematically combined to cancel out systematic errors, achieving accuracy comparable to expensive sensors

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3335007B1Navigation device with turntable for index measuring and method for operating the navigation device
Publication Date: 2019.09.04 NORTHROP GRUMMAN LITEF GMBH
  • EP3335007B1 patent drawingFigure 1a~1c
  • EP3335007B1 patent drawingFigure 2~3

AI summary

The invention relates to a navigation device comprising a turntable (1) which can be rotated about an axis (3) in at least two different rotary positions, in accordance with a rotary control signal. An inertial measuring unit (2) is arranged on the rotary table (1) which can be rotated with the rotary table (1). The quality of the measurement data can be determined by the initial measuring unit (2) with the help of an evaluation device. When the determined quality does not reach a predetermined minimum quality, the rotary table (1) rotates in the respective other rotary position.