Aircraft Data Transmission System Using Galvanic Isolation

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Solution Overview

Problem

Current data transmission systems in aircraft lack security and are not suitable for critical systems that could impact aircraft safety.

Innovation Solution

A data transmission system utilizing isolated communication links, such as controlled impedance cables, and a radiofrequency transmitter with an impedance matching network and electrical transformer for secure data transmission, while isolating the radiofrequency signal from the power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is transmitted via radio frequency waves through shared communication infrastructure, then communication capability is achieved, but security and reliability are insufficient for critical systems

Engineering Contradiction:
Improvedata transmission securityVSAvoidcommunication system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The communication link is segmented into isolated differential pairs, with each pair dedicated to specific data transmission tasks. This physical segmentation prevents interference and security breaches between different data streams, enhancing overall system reliability while maintaining manageable complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Differential signaling acts as an intermediary mechanism between transmitter and receiver, providing inherent noise rejection and signal integrity protection. This intermediary approach enables secure communication over shared infrastructure without requiring complex encryption or isolation hardware at each endpoint

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If power lines are used for data transmission, then infrastructure utilization is improved, but interference and security risks increase

Engineering Contradiction:
Improveinfrastructure utilizationVSAvoidpower supply interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces traditional single-ended signaling (analogous to mechanical systems) with differential signaling, which fundamentally changes the electromagnetic field distribution. This substitution eliminates common-mode noise from power lines by ensuring that interference affects both signal lines equally and is rejected at the differential receiver

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the electrical parameters of signal transmission by using balanced differential voltages instead of single-ended voltages. This parameter change transforms the system's immunity characteristics, making it insensitive to power line interference while maintaining compatibility with existing infrastructure

Inventive Principle:
Principle #35Parameter changes

3Reliability

If isolated communication links are used for secure transmission, then data security is enhanced, but system complexity and component requirements increase

Engineering Contradiction:
Improvedata transmission securityVSAvoidcommunication link structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The differential communication links are designed to be universal and multi-functional, serving both data transmission and inherent shielding functions simultaneously. This eliminates the need for separate isolation hardware while maintaining security, reducing overall system complexity despite the enhanced protection capabilities

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The differential signaling system provides self-service by inherently rejecting noise and interference without requiring external isolation components or complex error correction mechanisms. The signal structure itself provides the protection, eliminating the need for additional security hardware

Inventive Principle:
Principle #25Self-service

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

Enhances data transmission security and reliability by isolating communication links and preventing interference from the power supply, making it suitable for critical aircraft systems.

Implementation Method 1

The electrical transformer 46 is designed to galvanically isolate the transmitter 38 from the communication links 32, 34

Methodology Applied
Scientific EffectGalvanic isolation: Electromagnetic Induction

Implementation Method 2

The coupling capacitive component 60 and the additional coupling capacitive component 62 are designed to transmit the radio frequency signal and block the supply voltage

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

This filter 58, for example, consists of a transformer

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Data Source

PatentEP3776882B1Data transmission system
Publication Date: 2023.07.26 SAFRAN AEROTECHNICS SAS
  • EP3776882B1 patent drawingFigure 1~2
  • EP3776882B1 patent drawingFigure 3

AI summary

The invention relates to a data transmission system (26) comprising an emitting device (28), a receiving device (30) and a communication link (32), the emitting device (28) comprising: a radiofrequency emitter (38) connected to the communication link, a power line (48) connected to the communication link at a connection point (50), the power line having a supply voltage, and a capacitive coupling component (60) connected between the radiofrequency emitter and the connection point (50); the receiving device (30) comprising: a radiofrequency receiver (66) connected to the communication link for receiving said radiofrequency signal, a power line (80) connected to the communication link at a connection point (82), and a capacitive coupling component (92) connected between the point of connection and the radiofrequency receiver, said capacitive coupling components transmitting the radiofrequency signal and blocking the supply voltage.