Monopulse Secondary Surveillance Radar (MSSR) is a surveillance technique in worldwide use in which aircraft respond to transmissions, or interrogations, from a ground radar system. Reply transmitted by the aircraft is received by the ground radar and the aircrafts specific data is fed to a Radar Display System (RDS) for ATC use. The significance of MSSR data is that it enables ATCs to identify and maintain contact with aircraft and provides 3D positional information.
Technology has evolved and Mode S MSSR, where “S” stands for Selective, has now become the benchmark standard to which Air Navigation Service Providers (ANSPs) worldwide aspire to. As befits a nation embracing technical advancement, this technology has just been introduced to the United Arab Emirates, through the deployment of a Raytheon Series 300 Mode S MSSR system at Ras Al Khaimah International Airport.
MSSR Mode S transmissions are transmitted to each individual aircraft. This is because the availability of over 16 million addresses worldwide allows every aircraft to have its own unique address and each Mode S ground interrogator has an address.
This eliminates any risk of messages being corrupted by interference from any another message, one of the problems with conventional MSSR. It also means that once all ATC agencies are appropriately equipped, aircraft will be able to retain a single code, usually their flight number, for the whole duration of a flight, rather than having to change their code as they transfer from one ATC agency sector to another during the course of that flight.
Enhanced Mode S enables much longer response messages to be transmitted from air-to-ground and these extended messages contain invaluable data from the aircraft that can be used by ATC. This data, which is automatically extracted from the aircraft’s avionics system, includes the heading of the aircraft, its true airspeed, ground speed, 25feet height accuracy, rate of climb or descent, rate of turn and also the height selected by the flight crew on the flight management system and all the elementary Mode S MSSR data.
This data is a major advance to ATC’s since it can be selected on the radar display screens thus reducing the need for radio exchanges to check this information. It allows ATCs more time to concentrate on their primary function of maintaining a safe, orderly and expeditious air traffic flow.
This technology which is in operational use in Europe and the USA, is now available in the UAE. The Raytheon dual-channel Series 300 S MSSR system, which transmits both Mode S and conventional MSSR data simultaneously, provides ATCs at Ras Al Khaimah International Airport with air surveillance data for local use. The radar data will be supplied to the new Sheikh Zayed Air Traffic Control Center in Abu Dhabi for assistance in the provision of en route air traffic services within the UAE and neighboring regions.
Mode S data from the new Ras Al Khaimah radar
RAK International Airport can proudly state that it has the most advanced and capable civilian radar in the UAE region. RAK Airport’s new MSSR was commissioned on the 11th March 2009 and received GCAA approval to use it operationally on the 3rd June 2009 once the new RDS and recorders at the ATC tower receives GCAA approval. During MSSR’s Flight Trials it proved to have better than 99.92% probability of detection of responders within its 256 Nautical Miles radius. This radar is an invaluable tool ATCs now have to ensure a safe airspace and to optimize the usage of the airspace under RAK Airport’s control.
Sunday, October 25- 2009 @ 14:22 UAE local time (GMT+4) Replication or redistribution in whole or in part is expressly prohibited without the prior written consent of Mediaquest FZ LLC.