Integrated modular avionics

Integrated modular avionics (IMA) are real-time computer network airborne systems. This network consists of a number of computing modules capable of supporting numerous applications of differing criticality levels.

In opposition to traditional federated architectures, the IMA concept proposes an integrated architecture with application software portable across an assembly of common hardware modules. An IMA architecture imposes multiple requirements on the underlying operating system.[1]

History

It is believed that the IMA concept originated with the avionics design of the fourth-generation jet fighters. It has been in use in fighters such as F-22 and F-35, or Dassault Rafale since the beginning of the '90s. Standardization efforts were ongoing at this time (see ASAAC or STANAG 4626), but no final documents were issued then.[2]

First uses for this concept were in development for business jets and regional jets at the end of the 1990s and were seen flying at the beginning of the 2000s, but it had not been yet standardized.[3]

The concept was then standardized and migrated to the commercial Airliner arena in the end of the 2000s (Airbus A380 then Boeing 787).[2]

Architecture

IMA modularity simplifies the development process of avionics software:

  • As the structure of the modules network is unified, it is mandatory to use a common API to access the hardware and network resources, thus simplifying the hardware and software integration.
  • IMA concept also allows the Application developers to focus on the Application layer, reducing the risk of faults in the lower-level software layers.
  • As modules often share an extensive part of their hardware and lower-level software architecture, maintenance of the modules is easier than with previous specific architectures.
  • Applications can be reconfigured on spare modules if the primary module that supports them is detected faulty during operations, increasing the overall availability of the avionics functions.

Communication between the modules can use an internal high speed Computer bus, or can share an external network, such as ARINC 429 or ARINC 664 (part 7).

However, much complexity is added to the systems, which thus require novel design and verification approaches since applications with different criticality levels share hardware and software resources such as CPU and network schedules, memory, inputs and outputs. Partitioning is generally used in order to help segregate mixed criticality applications and thus ease the verification process.

ARINC 650 and ARINC 651 provide general purpose hardware and software standards used in an IMA architecture. However, parts of the API involved in an IMA network has been standardized, such as:

Certification considerations

RTCA DO-178C and RTCA DO-254 form the basis for flight certification today, while DO-297 gives specific guidance for Integrated modular avionics. ARINC 653 contributes by providing a framework that enables each software building block (called a partition) of the overall Integrated modular avionics to be tested, validated, and qualified independently (up to a certain measure) by its supplier.[4] The FAA CAST-32A position paper provides information (not official guidance) for certification of multicore systems.

Examples of IMA architecture

Examples of aircraft avionics that uses IMA architecture :

See also

References
  1. "ASSC - Evaluation of RTOS Systems" (PDF). assconline.co.uk. March 1997. Archived from the original (PDF) on 2011-09-04. Retrieved 2008-07-27.
  2. "Integrated Modular Avionics: Less is More". Aviation Today. 2007-02-01. Some believe the IMA concept originated in the United States with the new F-22 and F-35 fighters and then migrated to the commercial jetliner arena. Others say the modular avionics concept, with less integration, has been used in business jets and regional airliners since the late 1980s or early 90s
  3. "Technical hurdles delay Primus Epic program". ainonline.com. 2003-08-01. Archived from the original on 2010-07-16. Retrieved 2008-09-27. When Honeywell started the development program no one had ever certified an MAU. There were no regulations or TSO standards to follow and so Honeywell had to start from square one, working with the FAA and JAA to set the standards for what an MAU would be.
  4. René L. C. Eveleens (2 November 2006). "Integrated Modular Avionics - Development Guidance and Certification Considerations" (PDF). National Aerospace Laboratory. Archived from the original (PDF) on 2012-06-03. Retrieved 2011-06-25. Biggest challenge within this area is that modular avionics is a composition of building blocks, preferably supplied by different companies in the supply chain. Each supplier is supposed to bring its part to a certain level of qualification, and after this a system integrator can use these “pre-qualified” part in the overall certification process.
  5. "Avionics for the A380: new and highly functional ! Dynamic flightdeck presentation at Paris Air Show". Thales Group. 2003-06-17. Archived from the original on 2008-05-03. Retrieved 2008-02-09. Integrated Modular Avionics (IMA), based on standardised modules that can be shared by several functions. The IMA concept is very scalable, and delivers significant improvements in reliability, maintainability, size and weight.
  6. "Common Core System (CCS)". GE Aviation Systems. Retrieved 2008-02-09. GE has developed a compute platform running an ARINC 653 partitioned operating environment with an Avionics Full Duplex Switched Ethernet (AFDX) network backbone. The CCS provides shared system platform resources to host airplane functional systems such as Avionics, Environmental Control, Electrical, Mechanical, Hydraulic, Auxiliary Power Unit, Cabin Services, Flight Controls, Health Management, Fuel, Payloads, and Propulsion.
  7. "Dassault Falcon EASY Flight Deck". Honeywell. July 2005. Retrieved 2008-02-09. The heart of the EASy platform is two, dual-channel, cabinet-based modular avionics units (MAUs). Highly rationalized, the MAU integrates functional cards for several applications into a single module. Each functional card performs multiple tasks previously requiring dedicated computer processors.
  8. "Thales wins major Rafale through-life support contract from SIMMAD". Thales Group. Archived from the original on 2008-05-03. Retrieved 2008-02-09.
  9. "RAFALE". Dassault Aviation. 2005-06-12. Archived from the original on 2007-12-04. Retrieved 2008-02-09. The core of the enhanced capabilities of the RAFALE lies in a new Modular Data Processing Unit (MDPU). It is composed of up to 18 flight line-replaceable modules, each with a processing power 50 times higher than that of the 2084 XRI type computer fitted on the early versions of Mirage 2000-5.

IMA Publications & Whitepapers
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