Aircraft Bus System With Expanded CAN Identification Field
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Solution Overview
Problem
Current aircraft data bus systems, such as ARINC 429, are limited by unidirectional communication and require separate buses for each transmitter, while CAN standards offer bidirectional communication but lack efficient identification and prioritization for safety-critical systems.
Innovation Solution
A CAN data bus system with a 29-bit expanded identification field allows unique addressing of aircraft systems and prioritization, enabling flexible and expandable communication for safety-critical functions by using higher bits for priority and lower bits for system ID, aligned with ATA chapters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARINC 429 standard is used with unidirectional communication, then communication for safety-critical functions is ensured, but separate buses are required for each transmitter increasing device complexity
Solution Approach 1:
The patent merges multiple unidirectional communication channels into a single bidirectional bus system. By combining the transmission and reception functions into one shared bus with bidirectional communication capability, the system reduces the number of separate buses from multiple dedicated ARINC 429 buses to a single integrated CAN bus, thereby reducing device complexity while maintaining communication reliability through priority-based access control
Solution Approach 2:
The patent implements a universal bus system that can handle multiple communication directions and priorities through a single infrastructure. The bidirectional CAN bus serves all aircraft systems regardless of their specific communication needs, making the system multi-functional and adaptable to different criticality levels without requiring separate dedicated buses for each function
2Device complexity
If CAN standard with bidirectional communication is used, then device complexity is reduced, but efficient identification and prioritization for safety-critical systems is insufficient
Solution Approach 1:
The patent extends the traditional 11-bit CAN identifier to a 29-bit identifier, adding 18 additional bits of identification capability. This dimensional expansion in the identifier space allows for unique addressing of all aircraft systems and enables fine-grained prioritization through the high-order bits while maintaining compatibility with the existing CAN bidirectional communication framework
Solution Approach 2:
The patent applies different functional meanings to different portions of the expanded identifier field. The high-order bits are used for priority assignment to ensure safety-critical functions receive appropriate attention, while the low-order bits provide unique system identification. This localized functional assignment within the identifier structure enables both reliable prioritization and unique addressing simultaneously
3Reliability
If fixed region for system identification is implemented, then unique assignment of data packets is achieved, but flexibility for customer-specific configuration is reduced
Solution Approach 1:
The patent segments the 29-bit identifier field into distinct functional regions: a fixed region for system identification (using ATA chapter codes) and a variable region for priority assignment and other customer-specific configurations. This segmentation allows the fixed system identification portion to ensure unique assignment while the variable priority portion can be customized for different aircraft configurations and customer requirements without conflict
Data Source
AI summary
The present invention relates to a bus system for transmitting a data packet between multiple devices in an aircraft, which is based on the CAN data bus system, but has an expanded identification field, in which a fixed region is designed for identification of the manifold aircraft systems, through which each aircraft system may be addressed uniquely. According to an exemplary embodiment, the data packet may be sent with different priorities, through which “important” data packets have priority on the transmission medium.