GB/T 43671-2024
Space data and information transmission system Spacecraft CAN bus communication protocol (English Version)

Standard No.

GB/T 43671-2024

Language

Chinese, Available in English version

Release Date

2024

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China  CN  /  GB

Latest

GB/T 43671-2024

Introduction

Analysis of Spacecraft CAN Bus Protocol Architecture

OSI Model	CAN Protocol Layer	Core Functions	Special Requirements for Spacecraft
Application Layer	Application Layer	Information Exchange Protocol	Support multi-frame transmission (up to 2048 bytes)
Data Link Layer		Error Detection/Recovery Mechanism	Dual Bus Redundancy Switching Time≤16s
Physical Layer		Electrical Characteristics Specifications	Operating Temperature -55℃~+125℃

---

Key technical indicators of the physical layer

The standard stipulates that the characteristic impedance of the twisted pair is 120Ω±20Ω, and the bit timing requirements are:

• Synchronization segment (SYNC_SEG): fixed 1 time share
• Propagation segment (PROP_SEG): 1-8 time shares programmable
• Phase buffer segment: can be dynamically adjusted through resynchronization

Typical application scenario: Dongfanghong-5 satellite platform uses a 500kbps bit rate, and the terminal resistor uses a 120Ω±5% precision resistor.

---

Innovative design of data link layer

Frame type	Standard frame	Extended frame
Identifier length	11bit	29bit
Node capacity	64	64 (source) × 64 (destination)
Multi-frame transmission	Maximum 255 frames	Support cycle counting

Chang'e 5 probe adopts extended frame format, which is realized through multicast identification:

• 0x7F: Time synchronization broadcast
• 0xBF: Payload status multicast
• 0xFF: Emergency command broadcast

---

Reliability implementation suggestions

1. Topology design: A/B dual bus independent wiring, terminal resistors installed at both ends of the cable
2. Fault recovery: No response for 16 seconds triggers bus controller reset
3. Anti-interference: Acceptance code/shield code combination filtering to achieve accurate data reception

Application case of a remote sensing satellite:

• Platform bus: 500kbps, transmission of telemetry/remote control data
• Payload bus: 1Mbps, transmission of image data
• Dual bus switching time: 12.8ms

GB/T 43671-2024 Referenced Document

• GB/T 42041 Space terminology—Space data and information transfer
• GB/T 5271.9 Information technology--Vocabulary Part 9: Data communication

GB/T 43671-2024 history

• 2024 GB/T 43671-2024 Space data and information transmission system Spacecraft CAN bus communication protocol

Topics on standards and specifications

Standard and Specification