Summary of Terminology

Aeronautical Surveillance System is defined in ICAO Doc 9924 as a system that:

• "provides the aircraft position and other related information to ATM and/or airborne users. In most cases, an aeronautical surveillance system provides its user with knowledge of "who" is "where" and "when". Other information provided may include horizontal and vertical speed data, identifying characteristics or intent. The required data and its technical performance parameters are specific to the application that is being used. As a minimum, the aeronautical surveillance system provides position information on aircraft or vehicles at a known time".

The requirements for ATS surveillance systems are contained in the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444), Chapters 6 and 8. The aeronautical surveillance system defined in ICAO Doc 9924 comprises several elements which will be operated based on the requirements of a specific application. Neither the applications nor the end-users are part of the aeronautical surveillance system.

The surveillance service delivered to ground users may be based on a number of techniques:

• Independent Non-Cooperative Surveillance (as defined in ICAO 9924)

The aircraft position is derived from measurement not using the cooperation of the remote aircraft. An example is a system using PSR, which provides aircraft position but not identity or any other aircraft data.

• Independent Cooperative Surveillance (as defined in ICAO 9924)

The position is derived from measurements performed by a local surveillance subsystem using aircraft transmissions. Aircraft-derived information (e.g. pressure altitude, aircraft identity) can be provided from those transmissions. Examples include SSR, SSR Mode S and Wide Area Multilateration.

• Dependent Cooperative Surveillance (as defined in ICAO 9924)

The position is derived on board the aircraft and is provided to the local surveillance subsystem along with possible additional data (e.g. aircraft identity, pressure altitude).

The technologies are categorised as follows:

Composite Forms of Surveillance are means whereby two or more surveillance techniques are co-located to achieve either benefits in cost (deploying and maintaining at a single site may be cheaper than for a widely distributed set of systems) or which could bring functional benefits through the sharing of surveillance data (e.g. ADS-B collocated with a Mode S ground station could achieve RF efficiencies and improved detection capabilities)

SSR Mode 3/A Code Management Systems provide either a unique SSR Mode 3/A code to IFR/GAT flights operating within a defined volume of airspace, or the Mode S Conspicuity Code (SSR code A1000) to eligible flights operating within Mode S Declared Airspace.

• CCAMS is a SSR Mode 3/A code management system based on a centralised server,  located at EUROCONTROL’s Network Manager Operations Centre which is linked to the local flight data processing systems of participating ANSPs.  CCAMS provides a unique Mode 3/A SSR code to each flight operating within the CCAMS area.

• e-ORCAM is a SSR Mode 3/A code management process which enhances the capabilities of the existing ORCAM to provide:

                                           Multiple simultaneous assignments of the same code
                                           Geographical correlation of flights
                                           Directional assignment of codes
                                           Code reporting, and
                                           Code retention checking

(The latter two enhancements are to enable code usage monitoring and auditing, as required to comply with Commission Regulation (EU) No 677/2011 of 7 July 2011 which lays down detailed rules for the implementation of air traffic management (ATM) network functions)

Aircraft Derived Data

Different cooperative surveillance technologies obtain different information from the aircraft.

In its simplest form, the Mode A and Mode C information provided by the aircrafts SSR transponder can be classified as aircraft derived datat or donw-linked aircraft parameters.

The data from Mode-S ELS and EHS and ADS-B are listed below.