Decentralized Attitude Control Network for Spacecraft

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Solution Overview

Problem

Current attitude and orbit control systems for spacecraft face challenges in efficiently hybridizing data from different sensors, leading to overloading of the spacecraft bus, increased mass, and susceptibility to failure, while also requiring complex software controllability and restrictive data rate limitations.

Innovation Solution

A decentralized network architecture that separates the attitude and orbit control system into two networks, with the AOD network handling sensor data acquisition and hybridization, and the AOC network remaining centralized for control, using a star sensor as the network center for hybridization and providing autonomous position detection without relying on gyroscopes, and maintaining a redundant processor for reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor data is centrally evaluated in the satellite computer, then measurement precision is improved through synergistic evaluation, but device complexity increases and the spacecraft bus becomes overloaded

Engineering Contradiction:
Improveattitude determination precisionVSAvoidsoftware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the attitude determination software into modular functional blocks (sensor data acquisition, preprocessing, synergistic evaluation, output generation) that can be independently developed, tested, and maintained. This modular architecture reduces software complexity while preserving the ability to perform comprehensive sensor fusion for high-precision attitude determination.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple sensor types are integrated into a single hybrid sensor, then measurement precision is improved through complementary sensor synergies, but device complexity and susceptibility to failure increase

Engineering Contradiction:
Improvehybrid sensor precisionVSAvoidsystem reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a redundant processor that serves as a backup for the main processor in the hybrid sensor. This redundancy cushions against failures in the complex integrated sensor system, maintaining reliability while allowing the use of multiple sensor types for improved precision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If autonomous processing is implemented in each sensor, then ease of operation is improved, but loss of information occurs due to wasted synergies

Engineering Contradiction:
Improveautonomous operationVSAvoidsynergy information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent extracts the synergistic evaluation function from the individual sensors and places it in a dedicated processor unit. This allows each sensor to operate autonomously for ease of operation while the central processor unit captures and processes the synergistic information that would otherwise be lost.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If point-to-point data connections are added to the AOCS bus, then measurement precision is maintained, but weight and susceptibility to failure increase

Engineering Contradiction:
Improvedata transmission accuracyVSAvoidsystem mass
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent designs the processor unit to handle multiple sensor types and communication protocols through a universal interface. This multi-functionality allows the system to maintain measurement precision using the existing AOCS bus without requiring additional point-to-point connections, thereby avoiding increased mass.

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

Data Source

PatentEP2845808B1Position and orbit control system and method for operating the same
Publication Date: 2016.06.15 JENA OPTRONIK GMBH
  • EP2845808B1 patent drawingFigure 1
  • EP2845808B1 patent drawingFigure 2
  • EP2845808B1 patent drawingFigure 3

AI summary

A hybrid network of kinematic sensors of an attitude and orbit control system (AOCS) consisting of a star sensor (1) with an optical camera head (1a) and a processor unit (1b) which is provided as the central master processor unit (2a), and of further kinematic sensors (3), each consisting of a sensor element (3a) and a processor unit (3b) which are connected to the central processor unit (2a) via a first bus (4), wherein one of the further processor units (3b) is equivalent to the processor unit (1b) of the star sensor (1) and is provided as the central redundant processor unit (2b).and wherein the central processor units (2a) and (2b) are connected via a further bus (5) of a spacecraft equipped with the hybrid network by means of a central computer of the spacecraft (6) and the respective active central processor unit (2a) or (2b) provides all kinematic sensors with a uniform time clock via a synchronization line (7) and supplies the central computer (6) with hybridized kinematic measurement data (8) which are formed according to a hybridization method (10) from the synchronous kinematic measurement data (23) of the star sensor and the measurement data (24) of the other sensors.