This section illustrates the Selex Galileo approaches to define the concept of the “new” Avionics Architecture by defining, developing and validating the “avionics module”. The way of built with this different “avionics node” through the SPD features and functionalities will be part of to the Dependable Avionics scenario (WP7). These technologies will be implemented in embedded system prototypes that will be part of the nSHIELD demonstrators.
The nSHIELD drivers are to provide a scalable solution, to define a minimal set of nodes , to increase the number of supported function and to demonstrate fault tolerance and reconfiguration and so the high dependability of the SG for nSHIELD solution. An “avionics node” can be built with different pieces of the following part:
4.3.1Current System Configuration
The current implementation of a typical avionic system is mainly based on a Federated Architecture where several LRUs with remote processing capability and dedicated I/Os provides the requested functionality.
All the avionics functionalities such as
Navigation Management (including Guidance and Flight Management)
Communication (including also identification)
are based on an HW and SW Platform which usually differs between them according to the application where are used.
The trend for modern aircrafts is to support aircraft application with an Integrated Modular Avionic (IMA) platform. Platform that have to include always more functionality, starting from the navigation/mission functionality to the flight control function including also communication functionality.
To implement all the functionalities required therefore the IMA platform should be reconfigurable, reconfigurable means that IMA should be able to change the configuration of the avionic platform by moving application
Re-configuration should therefore improve the operational reliability of the aircraft while preserving (or improve) current levels of safety (aircraft systems have to enforce stringent safety requirements that address the effects of failures on the life of passengers). Operational reliability strong addresses the effect of failures on economic aspects of flight operations
Avionics systems rely on computing platforms, and these platforms must be designed to provide the required levels of safety, maintenance, overall flight functions (flight management, mission and navigation). The avionics functions must be sustained appropriately in order to ensure a safe flight, yet the hardware components on aircraft operate in a hazardous environment while running software that itself might contain defects.
Many techniques have evolved for constructing dependable computer platforms for avionics systems. Architectures have been developed that use various forms of redundancy and reconfiguration to allow continued operation when components fail. In addition, in many cases replicated components are separated within an airframe to prevent their simultaneous loss in the event that there is damage to the airframe. Various techniques are employed to aid in the correct construction of software, and software development is required to follow a rigorous process. Finally, various analysis techniques can be used to estimate some of the important probabilities related to dependability of computing platforms.
A dependable avionics system, therefore, is one that can be trusted to support safe aircraft operations.
A dependable avionics system needs to include the following attribute: Reliability, Availability, Safety, Confidentiality, Integrity, Maintainability. This means that the avionics system shall be nSHIELD compliant (SPD features satisfied).
The general dependability requirements for an avionics system/sub-systems, the SPD NODEs, shall include the nSHIELD SPD attributes.
With the IMA architecture (or distributed architecture) the avionics computer that implement flight management or flight control functions, needs to take in considerations also data confidentiality and data integrity, that are becoming increasingly important with increasing interconnectedness of dependable systems (i.e. also the communication control function: wide/narrow data link management system)
Either in a IMA or distributed architecture the fundamental components of avionics system architecture are computers (i.e. HW), data busses (i.e. Network) and the application (i.e. either SW services and/or the real application SW).
These components may be configured in various computing system architectures, where the purpose of an architecture is to meet the functional demands of the computing platform and the dependability requirements.
The key objective in moving towards a distributed Integrated Modular Avionic (IMA) architecture is to realize a new platform Hardware and Software based.
Figure - Modular Avionics Architecture to/from SELEX GALILEO Distributed Modular Avionics Architecture
The following figure shows a possible application/scenario for the Distributed Modular Avionics Architecture. The functionalities are distributed through the “computer #1”, “computer #2” and “computer #3”. The three computer have to be compliant the nSHIELD solution for Dependability, Security and Privacy.
The source/sink box represents the following equipment
EDU: Electrical Distribution Unit
WBDL: WideBand Data Link
SATCOM: Satellite Communications
FMS: Flight Management System
A/C : AIRCRAFT
NSU: Navigation Sensor Unit
Figure – Selex Galileo Distributed Modular Avionics Architecture for Surveillance System
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