"Mode S Comes of Age"
By Pascal Dias, Mode S Programme Manager
Introduction
The EUROCONTROL ATM 2000+ Strategy contains a formidable challenge for the
coming years, to double air traffic capacity without compromising safety.
Under the umbrella of the European Air Traffic Management Programme (EATMP)
managed by EUROCONTROL, Mode S – where the “S” stands for selective
addressing capability - is one of the key elements.
Why change the current surveillance system to Mode S?
Two major issues are facing the current Secondary Surveillance System.
First, the system, the principles of which remained largely unchanged for 40
years, is becoming saturated by the increasing level of signals on the 1030
/ 1090 MHz frequencies. This leads to interference and a degradation of the
"probability of detection” together with “label swaps”, where information,
presented to the controller on flight X is erroneously attached to the
position indicator of flight Y. Second, there is an insufficient number of
“Mode A codes” to meet the requirement of unique aircraft identification for
the expected future growth of air traffic in Europe.
Moreover, as there is currently no other surveillance system fit to
replace existing SSR, Mode S Elementary Surveillance has been recognised by
all stakeholders as an essential prerequisite for the implementation of the
EUROCONTROL ATM 2000+ Strategy.
What is Elementary Surveillance?
Mode S Surveillance is a next generation SSR mode in which aircraft, based
on their unique ICAO 24-bit address, are selectively interrogated (polling),
thus reducing the use of the 1030/1090 MHz Radio Frequencies. Altitude can
be reported in increments of only 25 feet and the flight plan callsign is
automatically downlinked to the ATM system. Together, these yield
significant benefits for the airspace users in the three prime areas of
Safety, Capacity and Efficiency.
 EUROCONTROL
Agency’s achievements.
The EUROCONTROL Mode S Programme is not only coordinating the planning of
Mode S implementation by the ATC Service Providers but is also developing a
set of common “tools” for them. Among those tools, there are operational
procedures, system implementation concepts, safety cases, and regulatory
material. There are also hardware and software components, amongst which was
the Mode S radar, called POEMS for Pre-Operational European Mode S. The
POEMS development was the most critical,, both in term of complexity and
costs. The POEMS project managed the common development of the Mode S ground
station design with two independent suppliers, Thales ATM and Raytheon.
These designs are now available for off-the-shelf acquisition by any
implementing organisation.
The Implementation of Mode S Elementary Surveillance
It is anticipated that by 2005, about 50 traditional SSR stations will have
been replaced by civil Mode S ground stations, all based on the
off-the-shelf “POEMS” designs.
Mode S at Airports
Many major European Airports are currently implementing a new form of ground
surveillance called Multilateration. It complements existing Airport Surface
Detection Equipment. The principle of the Multilateration system is to
locate and identify aircraft on the ground based on Mode S signals, thereby
contributing to making the gate-to-gate concept a reality.
Enhanced Surveillance
The Introduction of Mode S Elementary Surveillance is a first step along the
path of benefits that can be realised by the acquisition of airborne derived
data, not accessible to traditional SSR.
Enhanced Surveillance, i.e. the downlinking of an additional set of
Downlinked Aircraft Parameters (Heading, Speed, Selected Altitude, …) will
support a number of new ATM applications, among which the Controller Access
Parameter (CAP) Service and system improvements such as Level Bust Alerting
Tool. These all relate to improvements in tactical ATC.
Discussions with airspace users on the implementation of Enhanced
Surveillance have taken place over many years. Recently, France, Germany and
the United Kingdom made the common decision to coordinate their
implementation of Enhanced Surveillance. They cooperated in the development
of a Master Plan, demonstrating their commitment to harmonise their plans,
both from the regulatory and the service provision perspectives.
Enhanced Surveillance will be a reality by 2007 in European high density
airspace. It will pave the way towards more cooperative ATC, based on
increased information exchanges between all ATC partners, and more
specifically between the ground and the aircraft. In this context, and with
the aim of rationalising the avionics investments, Mode S extended squitter
is seen as the ADS-B datalink solution for the first ADS-B implementation
phase, both in the US and in Europe.
For further information, please contact:
Directorate of the General Secretariat/External and Public Relations
Tel.: +32 2 729 30 95
Fax: +32 2 729 91 98
Email: christos.petrou@eurocontrol.int
Pascal Dias, Modes S Programme Manager
Tel: +32 2 729 33 69
Fax: +32 2 729 90 86
Email: pascal.dias@eurocontrol.int
www.eurocontrol.int
|
