"Time-Triggered Protocol (TTP) for Integrated Modular Avionics"

Guenter Motzet, David A. Gwaltney (NASA)Dr. Guenther Bauer, Dr. Mirko Jakovljevic, and Leonard Gagea
TTTech Computertechnik AG


Traditional avionics computing systems are federated, with each system provided by a number of dedicated hardware units. Federated applications are physically separated from one another, and analysis of the systems is undertaken individually. Integrated Modular Avionics (IMA) takes these federated functions and integrates them on a common computing platform in a tightly deterministic distributed real-time network of computing modules in which the different applications can run. IMA supports different levels of criticality in the same computing resource and provides a platform for implementation of fault tolerance through hardware and application redundancy.  Modular implementation has distinct benefits in design, testing and system maintainability. 

This paper covers the requirements for fault-tolerant bus systems used to provide reliable communication between IMA computing modules. An overview of the Time-Triggered Protocol (TTP) specification and implementation as a reliable solution for IMA systems is presented. Application examples in aircraft avionics and a development system for future aerospace applications are covered. The commercially available TTP controller can also be implemented in an FPGA and the results from implementation studies are covered. The future direction for the application of TTP and related development activities are finally presented.


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