Towards more efficient trajectory information sharing
Introduction
The Automatic Dependent Surveillance - Contract (ADS-C) common service (ACS) is a service that distributes ADS-C data, such as extended projected profile (EPP), speed schedule, or meteorological (MET) information, downlinked from aircraft to relevant ground users, including air traffic service (ATS) units, the network manager (NM) system, airlines, and others.
Establishing multiple connections with different ground users and downlinking the same (or similar) information multiple times can strain air-ground datalink resources. The ACS reduces the number of simultaneous contracts needed to obtain the same data and improves the accuracy and reliability of predictions in a resource-efficient manner. This should also help accelerate the deployment of initial trajectory information sharing, which is a key enabler of the future European ATM system and a central component of the Single European Sky.
About the Solution
During a flight, aircraft systems have access to valuable information, including actual wind conditions, airframe configuration, airline policy settings, current flying mode, and exact weight. This data is used by avionic systems to generate accurate predictions, such as trajectory, speed, and estimated time of arrival at flight plan waypoints. These predictions can then be shared as the extended projected profile (EPP). The downlink of the EPP via ADS-C allows the integration of the aircraft view into the ground system, improving the accuracy and reliability of predictions. This enhances many ATM processes, including traffic flow management, 2D consistency check and conformance monitoring, vertical profile monitoring, conflict detection and resolution, traffic sequencing, and facilitation of continuous vertical evolution.
The common service collects ADS-C data from the aircraft using a single ATS B2 (ATS datalink service) application dialogue. It will establish one “periodic” and one “event” contract per aircraft flight for all its users and distribute the data to clients through system wide information management (SWIM)-compliant ground distribution services. Additionally, the service also supports ADS-C “demand” contracts to meet specific user data requests.
The common service offers the possibility to establish and maintain an ADS-C connection with an aircraft as early and as long as possible, covering all phases of flight. For that, the Solution relies on the following pre-requisites:
- Aircraft must support ADS-C downlinks as part of the ATS B2 services.
- The ground systems for datalink communications must support ADS-C services as part of the ATS B2 services while maintaining compatibility with controller pilot datalink communication (CPDLC) services and providing service to flights equipped only with aeronautical telecommunication network baseline 1 (ATN B1).
- The SWIM TI Yellow Profile solution is part of the SWIM infrastructure that enables the ACS.
Benefits
• Reduce ATN network load (avoiding redundancy on the air-ground link)
• Improve ADS-C data access and distribution
• Support high number of clients, less complexity for clients and lower deployment costs
• Reduce the risk of interoperability issues, minimising deployment fragmentation, and accelerating the deployment of Initial Trajectory Information Sharing
• Enhances a range of ATM procedures