Redundant Data Bus Frequency Diversity for HIRF Immunity

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Solution Overview

Problem

Data buses in aircraft are vulnerable to noise and interference from terrestrial and non-terrestrial sources, such as HIRF, which conventional shielding methods attempt to mitigate but increase weight and maintenance costs, and are less effective against 'in-band' interference.

Innovation Solution

Implementing a redundant data bus using unshielded twisted-pair wiring with multiple transmitter/receiver pairs operating in different frequency bands, isolated by band-pass filters, to ensure reliable data transmission by transmitting the same data signal in separate frequency bands, thereby providing immunity to HIRF-level RF noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If wire shielding is used to protect data buses from HIRF threats, then protection against electromagnetic interference is improved, but aircraft weight increases

Engineering Contradiction:
Improveprotection against electromagnetic interferenceVSAvoidaircraft weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent changes the operating parameters by using multiple frequency bands for data transmission. Instead of protecting a single frequency band with shielding, the system transmits redundant data at multiple frequencies, allowing the aircraft to communicate reliably without requiring heavy shielding for each band.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates copies of the data signal at different frequency bands. By transmitting redundant copies of the same data at multiple frequencies, the system ensures that if one frequency is blocked by interference, another copy can be received, eliminating the need for protective shielding.

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If wire shielding is used to protect data buses, then electromagnetic interference protection is improved, but maintenance requirements increase

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidmaintenance requirements
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The system changes from a physical protection approach (shielding that requires integrity verification) to a signal-level approach (multiple frequency bands with redundancy). This eliminates the need to periodically verify shielding integrity while maintaining protection against electromagnetic interference.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If wire shielding is used for data buses, then some interference protection is provided, but effectiveness against in-band interference decreases

Engineering Contradiction:
Improveinterference protectionVSAvoideffectiveness against in-band interference
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the frequency parameter by operating in multiple frequency bands simultaneously. This allows the system to bypass in-band interference by switching to or using alternative frequency bands where the interference is absent, making the communication reliable even when certain bands are blocked.

Inventive Principle:
Principle #35Parameter changes

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

This approach provides immunity to HIRF-level RF noise without the weight and maintenance burdens of conventional shielding, ensuring reliable data transmission across a wide range of frequencies while ignoring invalid signals, thus meeting regulatory requirements.

Implementation Method 1

each transmitter and its corresponding receiver are isolated from the twisted-pair wiring by matching band-pass filters tuned to the frequency band associated with the transmitter and receiver

Methodology Applied
Scientific EffectBand-pass filtering: Filter (electronic)

Implementation Method 2

the data signal may be simultaneously transmitted in separate frequency bands through the two or more transmitter/receiver pairs

Methodology Applied
Scientific EffectElectromagnetic transmission: Electromagnetic Induction

Data Source

PatentEP2448165B1Redundant data bus
Publication Date: 2018.11.07 THE BOEING CO
  • EP2448165B1 patent drawingFigure 1
  • EP2448165B1 patent drawingFigure 2
  • EP2448165B1 patent drawingFigure 3

AI summary

Technologies for implementing and utilizing a redundant data bus for the reliable transmission of data between communication endpoints are provided. A redundant data bus includes two or more transmitters configured to transmit the same data signal in separate frequency bands over twisted-pair wiring to corresponding receivers. A data signal containing input data received at an input communication endpoint is generated and the data signal is simultaneously transmitted through the two or more transmitters over the twisted-pair wiring to the corresponding receivers. The data contained in the data signals received at the receivers is validated, and output data is extracted from a valid data signal and made available at an output communication endpoint, while any invalid data signals are ignored.