Satellite Safety Services: Work In Progress
Nina Beebe is director for emerging markets at Access Partnership in London. She assists satellite service integrators, operators and others in securing market access and licenses on a global basis.Even before the Titanic, the reliability of radiocommunications was recognized as critical to saving lives. Safety took a huge leap forward in the ‘70s with the launch of the MARISAT system using L-band frequencies and ship-mounted steerable antennas to connect to maritime safety services. These and other systems were developed and ultimately incorporated in the Global Maritime Distress and Safety System (GMDSS), standardized by the International Maritime Organization in 1988.
Technology has not stood still. New systems are being considered for both aviation and maritime safety systems in L- and Ka-band. The International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) have developed safety standards for their respective sectors and have contributed significantly to improvements in the coverage and reliability of international transportation and travel. The ITU also plays a part in this, maintaining access to radio spectrum and ensuring the interconnection and reliable operation of global networks. It continues to define important regulations and standards for safety communications. Two current examples include satellite ADS-B and Ka-band VSAT systems.
ICAO has standardized a system of aircraft tracking called Automatic Dependent Surveillance Broadcast (ADS-B), in which aircraft derive their location and course from GPS and broadcast it to other aircraft and air-traffic controllers on the ground. The system is considerably more accurate than radar, provides more regular updates (twice per second), and permits aircraft to directly monitor other neighboring aircraft. The improvements to safety and reliability have meant that regulators in Europe and the United States have mandated the installation and use of ADS-B by all large commercial aircraft before 2020. However, the key advantages of ADS-B quickly disappear when aircraft leave the coverage of ground-based receivers, and Air-Traffic Controllers (ATC) can no longer directly receive their information. Minimum separation distances between aircraft, particularly on oceanic routes, are critical to safety and cannot be reduced unless controllers have reliable data on aircraft locations.
To overcome this shortfall, several satellite networks are proposing to carry ADS-B receivers to collect the broadcast signals from Low-Earth Orbit (LEO) and route them to ATC. Aireon, the developer of one such network, is planning to have global coverage by 2017. But the frequencies are allocated to the terrestrial service, and so the Radio Regulations must be amended to reflect and protect the collection of the signals by satellite. The ITU has the opportunity to do this at the next World Radio Conference, scheduled for 2015.
The growth in mobile VSAT equipment on ships, aircraft and vehicles has resulted in the development of new Ka-band satellite networks that can provide mobile services at higher capacities and lower costs. Inmarsat and Viasat, have announced high-capacity services to ships, aircraft and land-based vehicles beginning around 2016. Increased channel capacities open up new possibilities: remote monitoring of aircraft and ships, for operational and maintenance purposes, has become commonplace but rely upon narrow-band satellite links.
Broadband links would permit more detailed analysis and remote control of systems on ships and aircraft (and would even open up the option of removing the crew entirely and navigating remotely instead). Considerable interest in real-time monitoring of aircraft “black-box” data, arising from recent high-profile aviation incidents, is focusing attention on the possible standardization of a “black-box in the sky,” and the ITU Telecommunications Sector has announced an initiative to develop such standards.
The safety systems in which we rely for our security are the result of careful standardization and implementation. The ITU and other bodies must keep up with rapidly advancing technical developments, and ensure that new safety systems and services are implemented in a suitable timeframe, and protected to the same high degree as existing safety systems. VS