Optical Tracking System Using Angle-of-Arrival Sensors
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Solution Overview
Problem
Current object tracking systems face limitations due to susceptibility to noise, imprecise measurements, and latency issues, particularly in environments with metallic structures and varying lighting conditions, affecting the accuracy and speed of determining and tracking the position and orientation of objects.
Innovation Solution
An optical tracking system utilizing an array of point source emitters and angle of arrival sensors that create linear or cross patterns on a focal plane array, allowing for high-speed and accurate determination of object position and orientation by analyzing the angle of arrival of optical signals, with a processing system to calculate the pose of the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensors are used for tracking, then accuracy and detection range are improved, but susceptibility to metallic structures and field distortion increases
Solution Approach 1:
The patent replaces magnetic sensing systems with optical sensing systems. Specifically, it uses arrays of optical sensors (such as cameras or photodetectors) to detect optical emissions (light) from transmitters mounted on the tracked object, thereby eliminating susceptibility to metallic structures and magnetic field distortion while maintaining tracking accuracy.
Solution Approach 2:
The patent changes the physical parameter used for tracking from magnetic field properties to optical properties. By using optical emissions and optical sensors instead of magnetic sensors, the system transforms the measurement domain to one that is not affected by metallic interference, thus resolving the contradiction between accuracy and metallic susceptibility.
2Measurement precision
If optical sensors view illuminated patterns on the object, then position and orientation can be determined, but resolution is limited and sunlight effects cause errors
Solution Approach 1:
The patent employs periodic modulation of optical emissions from transmitters mounted on the tracked object. The optical sensors detect these modulated signals and use the periodic characteristics to distinguish transmitted signals from ambient sunlight, thereby eliminating sunlight interference while maintaining position and orientation determination accuracy.
Solution Approach 2:
The patent introduces modulated optical emissions as an intermediary carrier signal. Instead of directly viewing passive illuminated patterns, the system uses actively modulated light emissions from transmitters as a mediator that encodes position and orientation information while being distinguishable from ambient sunlight through its modulation characteristics.
3Speed
If inertial measurement units are used, then short-term tracking accuracy is improved, but IMU drift occurs over time requiring recalibration
Solution Approach 1:
The patent implements a feedback mechanism where optical sensors continuously track the position of transmitters mounted on the tracked object. This external optical feedback provides absolute position references that correct drift in inertial measurement units over time, maintaining both high update rates and long-term measurement stability without requiring frequent recalibration.
Solution Approach 2:
The patent merges inertial measurement units with optical tracking transmitters and sensors into a hybrid system. The IMU provides high-speed short-term tracking while the optical transmitter-receiver pair provides absolute position references, combining the advantages of both systems to achieve both high update rates and long-term stability.
4Reliability
If acoustic sensing systems are used, then all-weather operation is achieved, but acoustic update rate is low causing latency
Solution Approach 1:
The patent replaces acoustic sensing systems with optical sensing systems. By using optical emissions and optical sensors instead of acoustic sensors, the system achieves both all-weather operational reliability and high update rates, eliminating the latency inherent in acoustic measurement systems while maintaining reliability in various environmental conditions.
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 provides a computationally efficient, high-accuracy, and low-latency method for tracking objects, reducing errors and improving responsiveness in dynamic environments, while being robust to extraneous light sources and metallic interference.
Implementation Method 1
point source emitters that output respective optical emissions within the field-of-view (FOV) of a sensor array
Implementation Method 2
one or more optical angle of arrival sensors...with the optical elements arranged to resolve the optical emissions into one or more linear patterns on the FPA
Data Source
AI summary
An optical tracking system comprises an array of point source emitters that output respective optical emissions, and a plurality of angle of arrival sensors. Each sensor comprises one or more optical elements and a focal plane array (FPA), with the optical elements arranged to resolve the optical emissions into one or more linear patterns on the FPA. A processing system in communication with the sensors establishes the orientation and position of each of the optical emitters using the linear patterns. A headgear tracking system employs point source emitters on a piece of headgear, with front and rear arrays of angle of arrival sensors located in an aircraft cockpit; a processing system in communication with the sensor arrays establishes an orientation and position for each of the optical emitters on the headgear.