Magnetic Isolation Link for Spacecraft Data Transmission

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Solution Overview

Problem

Current spacecraft communication standards, such as SpaceWire and MIL-STD-1553, face challenges with high data rate requirements, susceptibility to noise and fault propagation, and increased size, mass, and power consumption due to the need for dual interfaces and complex electrical isolation methods.

Innovation Solution

A method and encoder/decoder system utilizing a twisted pair Ethernet compatible Physical Layer with an output buffer for prioritizing and managing data transmission over a magnetic isolation link, providing enhanced electrical isolation, longer cable lengths, and integrated power delivery, while supporting quality of service and error handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If SpaceWire standard is used for high data rate communication, then data rate is improved, but electrical isolation and noise susceptibility deteriorate

Engineering Contradiction:
Improvedata rateVSAvoidelectrical isolation
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces a magnetic isolation link as an intermediary component between sub-assemblies. This mediator provides galvanic isolation while enabling high-speed data transmission, thus resolving the contradiction between achieving high data rates and maintaining electrical isolation. The magnetic coupling allows signal transfer without direct electrical connection, preventing noise and fault propagation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional electrical connection system (direct wire connections with common 0V reference) with a magnetic field-based transmission system. By using magnetic coupling instead of direct electrical contact, the system achieves both high data rates and electrical isolation, as magnetic fields can transfer energy and information without requiring conductive paths.

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

2Reliability

If dual interfaces (MIL-STD-1553 and SpaceWire) are implemented for critical and payload data, then reliability is improved, but device complexity and mass increase

Engineering Contradiction:
Improvefault toleranceVSAvoidinterface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the magnetic isolation link a universal interface that can handle both critical TM/TC data and payload data through a single connection. This multi-functional link eliminates the need for separate MIL-STD-1553 and SpaceWire interfaces, reducing device complexity while maintaining reliability through its inherent electrical isolation and high data rate capabilities.

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

Solution Approach 2:

The patent merges the functions of critical data communication and payload data communication into a single magnetic isolation link. By combining what were previously separate interfaces into one unified system, the patent reduces the number of connectors, cables, and interface circuits, thereby reducing mass and complexity while maintaining the ability to handle different data types.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If SpaceWire only interface is used to reduce size and mass, then device complexity is reduced, but reliability deteriorates

Engineering Contradiction:
Improveinterface complexityVSAvoidfault tolerance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the fundamental parameter of electrical isolation from 'partial isolation with common 0V reference' to 'full galvanic isolation through magnetic coupling'. This parameter change enables the SpaceWire-only interface to achieve both reduced complexity and improved reliability, as the magnetic isolation link provides inherent fault tolerance without requiring redundant interfaces.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If LVDS 0V reference is shared between sub-assemblies to enable communication, then data transmission is enabled, but noise susceptibility and fault propagation increase

Engineering Contradiction:
Improvedata transmissionVSAvoidnoise susceptibility
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a magnetic coupling field as an intermediary that transfers data signals between sub-assemblies without requiring a shared 0V reference. This mediator enables data transmission while preventing noise and ground loops from affecting the communication, as the magnetic field transmission is immune to ground potential differences and electrical interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables reliable, high-data-rate communication with full electrical isolation, reduced size and mass, and efficient power delivery, addressing the limitations of existing standards by supporting longer cable lengths and integrating power and data transmission over a single cable.

Implementation Method 1

MIL-STD-1553 is magnetically coupled and provides a very high level of common mode electrical isolation and protection from fault propagation

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Implementation Method 2

A method and encoder/decoder system utilizing a twisted pair Ethernet compatible Physical Layer with an output buffer for prioritizing and managing data transmission over a magnetic isolation link

Methodology Applied
Scientific EffectElectromagnetic transmission: Electromagnetic Induction

Data Source

PatentEP4231118A1Data encoding and decoding
Publication Date: 2023.08.23 THALES ALENIA SPACE UK LTD

AI summary

A codec for transmission of data over a twisted pair Ethernet compatible Physical Layer is provided in which sub-packets intended for transmission are buffered for transmission in a sequence based on a priority determined based on quality of service requirements associated with each sub-packet, where the priority is updated at the encoder based on control tokens returned by the end point. These control tokens may provide CRC information, acknowledgement signals, and the like, generated by the end point decoder. This may allow for improved compliance with quality criteria by reprioritising underperforming communication channels, resending lost packets