UAV Motion-Based Calibration Without Magnetometer Interference

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Solution Overview

Problem

Conventional UAV magnetometer calibration is time-consuming and unreliable due to susceptibility to magnetic interference and spinning motors, making it difficult to determine calibration validity.

Innovation Solution

A motion-based calibration method for UAVs that utilizes an inertial measurement unit (IMU) vector and global positioning system (GPS) vector correlation to calibrate without relying on the magnetometer, employing a complementary filter to fuse accelerometer and gyroscope signals, and a histogram filter to align and refine the UAV heading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetometer calibration is performed using conventional methods, then calibration can be completed, but the process is time-consuming and the results are unreliable due to magnetic interference

Engineering Contradiction:

Improvemagnetometer calibration reliabilityVSAvoidcalibration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the calibration problem from the magnetometer-dependent approach and relocates it to the IMU-GPS system. By taking out the magnetometer from the calibration process entirely and using only accelerometer, gyroscope, and GPS data, the system avoids magnetic interference while maintaining calibration reliability and reducing time requirements

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the magnetic field-based magnetometer calibration with a mechanics-based approach using IMU sensors (accelerometer and gyroscope) combined with GPS. This substitution eliminates susceptibility to magnetic interference from spinning motors and environmental magnetic fields, providing reliable calibration without time-consuming procedures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If magnetometer calibration is performed, then calibration data is obtained, but the calibration is affected by magnetic interference from spinning motors and environmental sources

Engineering Contradiction:

Improvecalibration accuracyVSAvoidmagnetic interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the magnetometer from the calibration system entirely, extracting the harmful magnetic interference element from the measurement chain. By relying solely on IMU and GPS sensors, the system achieves calibration accuracy without being affected by magnetic fields from motors or environmental sources

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces GPS as an intermediary reference system that provides absolute position and orientation data independent of magnetic fields. This intermediary allows the IMU to be calibrated against a magnetic-free reference, eliminating the harmful effect of magnetic interference on calibration accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Provides a reliable and efficient calibration process that is not affected by magnetic interference, reducing calibration time and ensuring accurate UAV navigation.

Implementation Method 1

employing a complementary filter to fuse accelerometer and gyroscope signals

Methodology Applied

Scientific EffectComplementary filtering:

Implementation Method 2

a histogram filter to align and refine the UAV heading

Methodology Applied

Scientific EffectHistogram filtering:

Implementation Method 3

computing an inertial measurement unit (IMU) vector associated with a UAV direction

Methodology Applied

Scientific EffectInertial measurement:

Implementation Method 4

a global positioning system (GPS) vector associated with a GPS orientation

Methodology Applied

Scientific EffectGlobal positioning:

Data Source

PatentUS20260050091A1Motion-Based Calibration Of An Aerial Device

Publication Date: 2026.02.19 SKYDIO INC

AI summary

A calibration of an unmanned aerial vehicle is performed without the use of a magnetometer. The unmanned aerial vehicle generates a first acceleration vector in a navigation frame of reference and a second acceleration vector in a GPS frame of reference. The unmanned aerial vehicle estimates a heading of the unmanned aerial vehicle based on the first acceleration vector and the second acceleration vector. The unmanned aerial vehicle performs a calibration based on the estimated heading of the unmanned aerial vehicle.