Optically Pumped Magnetometer Filtering for UAV Rotor Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional magnetometers are too large, heavy, and insensitive for smaller aerial vehicles, while optically pumped magnetometers (OPMs) are sensitive but struggle with environmental noise, making them unsuitable for high-sensitivity applications on smaller aerial vehicles due to the lack of effective filtering techniques.
Innovation Solution
A method and device for filtering magnetic field measurements from an OPM on an unmanned aerial vehicle to exclude contributions from the vehicle's rotor, using techniques like bandpass filtering, demodulation, and correcting for time-based jitter, allowing detection of a magnetic beacon with high sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional magnetometers are used, then the device is simple and robust, but the size and weight are too large for smaller aerial vehicles and the sensitivity is insufficient
Solution Approach 1:
The patent replaces traditional inductive magnetometers with optically pumped magnetometers (OPMs) that use quantum optical effects instead of mechanical induction. The OPM uses laser-excited alkali metal vapor in a magnetic field to detect magnetic field changes through optical signal modulation, achieving high sensitivity while reducing size and weight for aerial vehicle applications
2Weight of moving object
If optically pumped magnetometers are used, then the size and weight are reduced for smaller aerial vehicles, but the high sensitivity causes environmental noise and background fields to dominate the measurements
Solution Approach 1:
The patent extracts and removes harmful environmental noise and background field contributions from the OPM measurements through signal processing techniques. It separates the useful magnetic field signal from unwanted noise by identifying and excluding frequency components corresponding to environmental interference, allowing high-sensitivity detection despite the noisy operating environment of aerial vehicles
Solution Approach 2:
The patent employs dynamic signal processing that adapts to the time-varying nature of environmental noise and magnetic field conditions. It uses time-dependent filtering and frequency analysis to dynamically distinguish between stable magnetic field signals and transient noise, enabling reliable detection in the changing electromagnetic environment of moving aerial vehicles
3Object-affected harmful factors
If conventional filtering techniques are applied to OPM measurements, then some noise reduction is achieved, but the techniques are not suitable for the dynamic response of atomic magnetometers and do not provide sufficient sensitivity
Solution Approach 1:
The patent changes the filtering parameters and signal processing methods to match the dynamic response characteristics of atomic magnetometers. It uses frequency-domain analysis adapted to the OPM's temporal response profile, applying filters and processing techniques optimized for atomic quantum sensor characteristics rather than conventional inductive magnetometer response, thereby maintaining high sensitivity while achieving effective noise reduction
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
Enables high-sensitivity detection of magnetic beacons by filtering out rotor noise, enhancing the versatility and efficiency of OPMs on smaller aerial vehicles.
Implementation Method 1
An optically pumped magnetometer (OPM) is a form of quantum sensor which is capable of generating highly sensitive magnetic field measurements
Implementation Method 2
The alkali metal vapour can be hermetically sealed within a microfabricated cell, and the magnetic resonance signal is optically detected and demodulated at the magnetic resonance frequency
Implementation Method 3
The filtering of the magnetic field measurements may comprise applying a bandpass filter to the magnetic field measurements, the bandpass filter being configured to pass signals at a transmission frequency of the magnetic beacon
Implementation Method 4
The filtering of the magnetic field measurements may comprise demodulating the magnetic field measurements
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
There is provided a method of filtering magnetic field measurements generated by an optically pumped magnetometer mounted to an unmanned aerial vehicle. The method comprises filtering the magnetic field measurements to obtain filtered magnetic field measurements which exclude a contribution from a rotor of the unmanned aerial vehicle. The method also includes detecting a magnetic beacon based on the filtered magnetic field measurements. Also provided are devices configured to perform this method.