The conventional 1553 buses are constructed using a main bus structure with multiple stub connections and terminated with 78-ohm resistors at both ends. However, a major challenge arises when one of these termination resistors is damaged or disconnected. Unfortunately, existing market tools fail to identify this issue, resulting in a marginal signal-to-noise ratio that can still detect 1553 messages on the ground. However, during flight, noise levels escalate, leading to communication failures that are hard to diagnose during regular maintenance checks.
Common Challenges Faced:
Often, maintenance teams, facing communication breakdowns, have replaced multiple LRUs (Line Replaceable Units) in aircraft and platforms, only to find the issues persisting. This cycle of replacing components without addressing the root cause leads to continued communication breakdowns.
Our Innovative Solution:
To advance avionics systems maintenance, Sital Technology introduces an advanced diagnostic tool for effective identification of faults in the 1553 bus. This tool not only pinpoints faults related to termination resistors but also detects potential coupler failures, enhancing diagnostic capabilities significantly.
Learning from CAN BUS Technology:
A critical analysis of automotive systems using CAN BUS topology highlights a more effective strategy. In CAN BUS, termination resistors (120 ohms) are typically integrated within the edge Electronic Control Units (ECUs) at both ends of the bus. Consequently, whenever an ECU is replaced due to communication failures, the termination resistors are automatically replaced, ensuring continued robustness of the system.
Proposed Strategy for 1553 Buses:
Our proposed strategy, inspired by CAN BUS, involves modernizing 1553 bus systems with cutting-edge solutions to ensure enhanced communication reliability. Specifically, integrating the 78-ohm termination resistors inside the LRUs at both ends of the bus could drastically improve system resilience. Additionally, these terminating LRUs should adopt direct coupling rather than transformer coupling for enhanced efficiency.
Adopting this strategy, mirroring successful automotive industry practices, offers a reliable solution to strengthen 1553 bus systems. By addressing the inherent weaknesses in current bus topology, this proposal aims to mitigate communication failures and significantly improve maintenance efficiency. Embracing these changes will lead to a significant leap in avionics communication technology, benefiting the industry at large.
Founder and CTO
Sital Technology, a leader in avionics communication solutions, is dedicated to innovating and improving aviation technology.