Gravity Gradiometer RF Interference Shielding

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Solution Overview

Problem

Gravity gradiometers face challenges in accurately measuring the gravity gradient tensor due to interference from external RF sources, which can lead to incorrect measurements and noise in the signals, especially when used in airborne applications.

Innovation Solution

A gravity gradiometer design that incorporates a relay and a three-terminal cap with a feed-through filter to protect the superconducting circuitry from RF interference, using a container with a feed-through filter and a relay to ensure that signals can be passed while preventing external RF interference from reaching the superconducting components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If connectors are provided to connect internal wiring within the Dewar to external measuring equipment, then signals can be transmitted to external equipment, but RF interference from external sources can pass into the superconducting circuitry causing incorrect measurements and noise

Engineering Contradiction:
Improvesignal transmission to external equipmentVSAvoidRF interference from external sources
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A feed-through filter is introduced as an intermediary component in the connector pathway. This filter allows desired measurement signals to pass through from the superconducting circuitry to external equipment while blocking harmful RF interference from external sources, thus resolving the contradiction between signal transmission and RF protection

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an electrical copy or equivalent protective function using the feed-through filter that replicates the ideal scenario of complete RF isolation while maintaining signal transmission capability, effectively copying the protective function without requiring complete physical isolation

Inventive Principle:
Principle #26Copying

2Measurement precision

If superconducting components are used to measure gravitational gradient, then high measurement precision can be achieved, but the components become vulnerable to RF interference from external sources

Engineering Contradiction:
Improvegravitational gradient measurement precisionVSAvoidmeasurement reliability under RF interference
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The feed-through filter acts as a protective intermediary between the sensitive superconducting measurement components and the external RF environment, allowing the high-precision measurement function to be maintained while filtering out RF interference that would compromise measurement reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The feed-through filter creates an electromagnetically inert environment for the superconducting components by blocking RF interference, similar to how an inert gas atmosphere protects chemical reactions, thus preserving both measurement precision and reliability

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 solution effectively reduces RF interference, enhancing the accuracy of gravity gradient measurements by ensuring that the superconducting components within the Dewar are shielded from external noise, thereby improving the precision of the measurements taken by the gradiometer.

Implementation Method 1

a feed through filter in the container for connection to a lead within the Dewar

Methodology Applied
Scientific EffectRF filtering: Filter (electronic)

Implementation Method 2

a relay electrically connected to the three terminal cap; and an output terminal on the container for connecting the relay to an external lead

Methodology Applied
Scientific EffectElectromagnetic relay switching: Relay

Implementation Method 3

a sensor for measuring the components of the gravity gradient tensor, the sensor including super-conducting componentry

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP2089741B1Gravity gradiometer
Publication Date: 2015.03.25 TECHNOLOGICAL RESOURCES PTY LTD
  • EP2089741B1 patent drawingFigure 1~2
  • EP2089741B1 patent drawingFigure 3~4
  • EP2089741B1 patent drawingFigure 5~7

AI summary

A gravity gradiometer is disclosed which has a pair of sensor bars (41, 42) mounted in housings (43) and (45). Transducers (71) are located adjacent the bars for measuring movement of the bars in response to the gravity gradient tensor. Signals from the transducers are supplied to a SQUID device (367) for processing the signals. A connector is supplied for connecting the circuitry to external equipment which comprises a container (560) having a feed through filter (564), a three terminal cap (565), a relay (566) and an output terminal. The output terminal is connected to further RF attenuation which comprises a second connector (5b) having parallel inductors and resistors.