Virtual sensor and compass calibration

Patent metadata

Field	Value
Publication number	US-11585658-B2
Application number	US-201916455782-A
Country	US
Kind code	B2
Filing date	Jun 28, 2019
Priority date	Jun 28, 2019
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

An unmanned aerial vehicle includes one or more magnetometers, configured to detect a magnetic field and to output magnetometer data corresponding to a magnitude of the detected magnetic field; a position sensor, configured to detect a position of the unmanned aerial vehicle relative to one or more reference points, and to output position sensor data representing the detected position; one or more processors, configured to control the unmanned aerial vehicle to rotate about its z-axis; receive magnetometer data comprising a plurality of z-axis directional measurements taken during the rotation about the z-axis; receive position sensor data and determine from at least the position sensor data a magnetic field inclination of the detected position; and determine a z-axis magnetometer correction value as a difference between the received magnetometer data for the z-axis and the determined magnetic field inclination.

First claim

What is claimed is:

1. An unmanned aerial vehicle comprising:
one or more magnetometers, configured to detect a magnetic field and to output magnetometer data corresponding to a magnitude of the detected magnetic field;
a position sensor, configured to detect a position of the unmanned aerial vehicle relative to one or more reference points, and to output position sensor data representing the detected position;
one or more processors, configured to:
control the unmanned aerial vehicle to rotate about its z-axis;
receive magnetometer data comprising a plurality of z-axis directional measurements taken during the rotation about the z-axis;
receive position sensor data and determine from at least the position sensor data a magnetic field inclination of the detected position;
determine a z-axis magnetometer correction value as a difference between the received magnetometer data for the z-axis and the determined magnetic field inclination;
wherein the one or more processors are further configured to receive magnetometer data comprising a plurality of x-axis directional measurements and y-axis directional measurements taken during the rotation about the z-axis, and to determine from the received x-axis directional measurements and y-axis directional measurements an x-axis magnetometer correction value and a y-axis magnetometer correction value;
wherein determining the z-axis magnetometer correction value comprises determining the z-axis magnetometer correction value based on the magnetic field inclination, a value corresponding to the x-axis magnetometer correction value, a value corresponding to the y-axis magnetometer correction value, and the plurality of z-axis directional measurements.

2. The unmanned aerial vehicle of claim 1 , wherein the one or more processors are further configured to calibrate the magnetometer by the correction value.

3. The unmanned aerial vehicle of claim 1 , wherein the one or more processors are further configured to average the plurality of z-axis directional measurements to obtain an average magnitude of the detected magnetometer data for the z-axis, and wherein determining the z-axis magnetometer correction value as a difference between the received magnetometer data and the magnetic field inclination comprises comparing the averaged magnitude of the plurality of measurements to the magnetic field inclination.

4. A method of calibration comprising
detecting a magnitude of a magnetic field relative to a y-axis of an unmanned aerial vehicle;
controlling the unmanned aerial vehicle to rotate about its z-axis;
determining a plurality of z-axis directional magnetic field measurements during the rotation about the z-axis;
determining a position of the unmanned aerial vehicle relative to one or more reference points;
determining a magnetic field inclination corresponding to the detected position;
determining a z-axis correction value as a difference between the detected z-axis directional magnetic field measurements and the determined magnetic field inclination;
further comprising taking a plurality of x-axis directional measurements and y-axis directional during the rotation about the z-axis, and determining from the received x-axis directional measurements and y-axis directional measurements an x-axis magnetometer correction value and a y-axis magnetometer correction value;
wherein determining the z-axis magnetometer correction value comprises determining the z-axis magnetometer correction value based on the magnetic field inclination, a value corresponding to the x-axis magnetometer correction value, a value corresponding to the y-axis magnetometer correction value, and the plurality of z-axis directional measurements.

5. The method of calibration of claim 4 , further comprising calibrating the magnetometer by the correction value.

6. The method of calibration of claim 4 , further comprising averaging the plurality of z-axis directional measurements to obtain an average magnitude of the z-axis directional magnetic field measurements; and wherein determining the z-axis magnetometer correction value comprises comparing an averaged magnitude of the plurality of measurements to the magnetic field inclination.

Assignees

• Intel Corp

Inventors

• Gurdan Tobias
• Gurdan Daniel

Classifications

• B64U2101/30

  for imaging, photography or videography · CPC title

• B64U2201/102

  adapted for flying in formations · CPC title

• B64U10/13

  Flying platforms · CPC title

• B64U50/19

  using electrically powered motors · CPC title

• B64U2201/10

  autonomous, i.e. by navigating independently from ground or air stations, e.g. by using inertial navigation systems [INS] · CPC title