Orientation Tracking System with Optical Inclinometer Calibration
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Solution Overview
Problem
Conventional head orientation tracking systems fail in high electromagnetic environments and suffer from drift issues due to stochastic noise in inertial mass MEMS sensors, making them inaccurate for use on flight decks.
Innovation Solution
A dual-tracking system that includes inclinometers with a light source, light sensor, and light obscuring material to reduce drift, using a combination of light emitting diodes (LEDs) and photodiodes, and employing a method to calculate roll, pitch, and yaw with a calibration factor to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If inertial mass MEMS sensors are used for orientation tracking, then the system can operate without line of sight, but the system suffers from stochastic noise that creates considerable drift over time
Solution Approach 1:
The patent combines an inertial tracking system (providing orientation data without line of sight) with a visual fiducial marker system (providing drift-free orientation references). The system merges data from both sources, using the visual system to periodically calibrate and correct drift in the inertial system, achieving both operational flexibility and measurement precision.
Solution Approach 2:
The system implements feedback by continuously comparing orientation measurements from the inertial sensors with reference orientations derived from visual fiducial markers. When drift is detected in the inertial system, the visual system provides corrective feedback to realign the orientation tracking, maintaining accuracy over time.
2Measurement precision
If magnets are used for head tracking, then the system can track position and orientation, but the system does not operate adequately in high electromagnetic environments
Solution Approach 1:
The patent replaces magnetic field-based tracking with a visual optics-based tracking system using fiducial markers and cameras. This substitution eliminates sensitivity to electromagnetic interference while maintaining position and orientation tracking capabilities through optical pattern recognition and geometric calculations.
3Measurement precision
If ultrasonic or IR technologies are used, then the system can track orientation, but the system requires a direct line of sight
Solution Approach 1:
The system segments the tracking function into two complementary components: an inertial sensor system that provides continuous orientation data without line of sight requirements, and a visual fiducial marker system that provides periodic calibration references. This segmentation allows the system to operate in environments where continuous line of sight is not available.
4Measurement precision
If video tracking is used, then the system can track head orientation, but the system is bulky and operates slowly
Solution Approach 1:
The patent extracts and isolates only the essential visual element (fiducial markers) needed for calibration, removing the need for bulky video cameras and complex image processing systems. The inertial sensors handle continuous tracking, while the simplified visual markers provide periodic calibration, reducing overall system complexity and size.
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
The system effectively reduces drift and provides accurate orientation tracking in high electromagnetic environments, enhancing the reliability of head orientation tracking systems for applications like flight decks.
Implementation Method 1
The light source may include a light emitting diode (LED). The light sensor may include a photodiode or a phototransistor.
Implementation Method 2
a light obscuring material within the inclinometer for obscuring the light between the light source and light sensor
Implementation Method 3
Each inclinometer may also include a fluid therein for stabilizing the ball.
Data Source
AI summary
An orientation tracking system including a first tracking system subject to drift. A second tracking system is configured to provide an output for calibrating the first tracking system to reduce the drift of the first tracking system. The second tracking system includes at least one inclinometer, each inclinometer including a light source adjacent one side of the inclinometer, a light sensor adjacent an opposing side of the inclinometer, and a light obscuring material within the inclinometer for obscuring the light between the light source and light sensor to indicate an orientation of the inclinometer.