Resonant Magnetometer for Stealth Detection
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Solution Overview
Problem
Conventional magnetometers lack the necessary resolution and portability to detect stealthy military equipment at great distances without cryogenic cooling and are saturated by the earth's magnetic field, making them ineffective for military surveillance.
Innovation Solution
A magnetometer with a mechanically resonant structure and high quality factor, capable of resonantly amplifying external magnetic fields, using a proof mass and optional magnetic flux modulators, readout devices, and cryogenic cooling to enhance resolution and dynamic range, while compensating for the earth's magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetometers are used, then portability and compactness are achieved, but measurement precision and resolution are insufficient to detect stealthy military systems
Solution Approach 1:
The patent employs a mechanically resonant structure that vibrates at a specific resonant frequency to amplify the magnetic field signal. The resonant structure converts weak magnetic field interactions into mechanical vibrations that can be detected with high precision, thereby improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The patent changes the operating parameters by tuning the resonant frequency of the mechanical structure to match the frequency of the magnetic field signals being detected. This frequency matching maximizes the amplification effect and detection sensitivity, achieving high resolution through parameter optimization rather than complex system architecture
2Measurement precision
If SQUID sensors are used to achieve high resolution, then measurement precision improves, but device volume increases significantly
Solution Approach 1:
The patent replaces the complex superconducting quantum interference device (SQUID) system with a mechanically resonant structure. This substitution uses simple mechanical vibration and resonance principles instead of complex quantum phenomena, achieving comparable or superior resolution with a dramatically reduced sensor volume suitable for portable applications
3Measurement precision
If cryogenic cooling is implemented to reduce noise, then measurement precision improves, but device complexity and operational constraints increase
Solution Approach 1:
The mechanically resonant structure inherently provides noise filtering through its resonant frequency selectivity. The structure naturally amplifies signals at its resonant frequency while attenuating other frequencies, providing built-in noise reduction without requiring external cryogenic cooling systems or complex temperature control mechanisms
4Volume of moving object
If SERF magnetometers are used for miniaturization, then device volume decreases, but the sensor becomes saturated by the earth's magnetic field
Solution Approach 1:
The mechanically resonant structure operates based on mechanical vibration principles that are not affected by static magnetic fields like the Earth's field. The resonant frequency is determined by mechanical properties (mass, stiffness) rather than magnetic field conditions, allowing the sensor to maintain its detection capability in various environmental conditions including the presence of Earth's magnetic field
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 magnetometer achieves ultra-low noise levels of 10 fT/√Hz, enabling detection of stealthy military systems at long ranges and operating without cryogenic cooling, while maintaining compactness and resistance to the earth's magnetic field.
Implementation Method 1
The resonant structure comprises a proof mass that is magnetized, and a mechanism that suspends the proof mass and exerts a restoring force on it. The resonant structure oscillates naturally at its resonance frequency.
Implementation Method 2
The resonant structure comprises a proof mass that is magnetized
Data Source
AI summary
An ultra-low noise sensor for magnetic fields comprises a mechanically resonant structure having a magnetized proof mass. The displacement of the proof mass due to a magnetic field provides a high resolution and highly amplified measurement of magnetic field fluctuations near the resonance frequency. A flux modulator may be used with the resonant structure to amplify magnetic fluctuations in a non-resonant frequency band. The resonant structure, combined with a high resolution readout device and a frequency-compensating numerical processor, can amplify magnetic fluctuations in a broad range of frequencies. A solenoid coil surrounding the resonant structure may be used to null the quasi-static earth's magnetic field and thereby increase the dynamic range of the sensor. Cryogenically cooling the resonant structure can improve the resolution of the sensor. A magnetometer that embodies features of the present invention is miniaturized and has improved amplification and resolution at room temperature.