AIM Service Layer (AIMSL)

Introduction

The pan-European AIS Database (EAD) already offers wide-spread access and dissemination of Aeronautical information to external systems in a secure and reliable manner. Historically this has been built upon JMS based SonicMQ (MoM), with B2B clients accessing the services/data via a Java-based interface called ESI (EAD System Interface).

In EAD Release 6 Extension 1, a new subsystem will be added to the EAD called the AIM Service Layer (AIMSL). With this subsystem, the EAD intends to begin the move away from proprietary interfaces and to deliver system functionality as a set of interoperable services, according to Service-Oriented Architecture (SOA) principles.

Objectives

The main objectives for the AIMSL are to:

• Provide interfaces to EAD subsystems using open, standard technologies that enable interoperability, in particular web services
• Remove dependencies on a bespoke client API and dedicated middleware;
• Provide the possibility to develop value-added services for clients without directly impacting the back-end subsystems (SDO, INO, PAMS).

Examples of the technologies that will be applied are:

• HTTP as the primary network protocol
• SOAP/XML as the initial payload format
• XML Schema for the XML structure
• UDDI for web services registry and lookup
• WSDL to describe web services interfaces
• WFS to provide access to spatial data

Architecture

AIMSL provides the middle tier of a 3-tier architecture. It sits between the consumer applications and the backend EAD subsystems, providing interfaces and value-added services as required.

Work Plan

AIMSL is planned to be introduced with EAD Release 6 extension 1. The basic AIMSL platform will be implemented, along with an initial set of web services. These are intended to cover SDO-DU functions (SDO reporting and SDO query), PAMS functions (Search and Download) and INO-DU functions (Single NOTAM Retrieval and PIB Retrieval).

In future EAD releases, additional web services will be implemented, including a publish-subscribe mechanism to allow data download based on a subscription, and WFS access to EAD spatial data.

Relationship with SESAR

The SESAR (Single European Sky ATM Research) programme is intended to define, develop and deploy the next generation ATM system for Europe. It consists of a number of different key features and concepts. One of these is System-Wide Information Management (SWIM). This defines how information shall be managed, maintained and distributed. SWIM is being developed based on a set of principles including:

• Separation of information provision and consumption
• Loose system coupling
• Use of open standards
• Use of service-oriented architecture

AIMSL is being developed in accordance with these principles. The intention is that through AIMSL, the EAD will be able to act as an Aeronautical Information Management System within the SESAR target concept and exchange information with other systems through SWIM.

SWIM is being developed in SESAR by a number of dedicated projects that fall into three categories:

• WP8.1 : Information Data Modelling
• WP8.3 : Information Service Modelling
• WP14 : SWIM Technical Architecture

AIMSL shall follow developments within these projects and where appropriate, shall use the validated models and specifications produced as an input to its own evolutions. The goal is that at the end of the SESAR development phase, the EAD will be recognised as a SWIM-compliant AIM system.