The automatic dependent surveillance-broadcast (ADS-B) is a technology that is used in tracking aircraft. This system is much different from the radar system that works by bouncing radio waves back from the terrestrial fixed antennae from airborne targets and interpreting the signal. The technology uses the typical Global Navigation Satellite System (GNSS) technology and a simple broadcast communication link as its basic components. Additionally, unlike the conventional radar system ADS-B’s accuracy is not interfered with range, target altitude or atmospheric conditions. The update intervals is also not dependent on reliability of mechanical antennae’s or rotational speeds (Weijun, Tong, & Wentao, 2012).
The ADS-B system is made up of three major components; an airborne component, Ground infrastructure and necessary operating procedures. It has a transmitting system that includes the message generation and transmission functions at the source a transport protocol which includes the 1090ES or 978 MHz UAT and a receiving sub system that includes message reception and assembly of reports at the receiving destinations (Weijun, Tong, & Wentao, 2012).
In a distinct application, an ADS-B enabled aircraft utilizes a GNSS or GPs receiver to get its exact position from the GNSS constellation, it then combines this position with available number of aircraft discrete which include speed, altitude, flight number and heading. The collected information is simultaneously broadcasted to the ADS-B ground or satellite communication transceivers and other ADS-B enabled aircrafts. The ADS-B ground or the Satellite communication the relays the position of the aircraft and additional information in real time to the air traffic control centers. In addition to the physical position about each air crafts, the universal access transceiver (978 MHz) has the capability to send real time flight information service which includes weather and other data to the aircraft (Weijun, Tong, & Wentao, 2012).
ADS-B consist of two different services the ADS-B out and the ADS-B in, with this attributes its going to replace the radar as a primary surveillance for air traffic worldwide control. The DBS-B out periodically broadcasts information regarding each aircraft which includes identification, altitude, current position, and velocity via an onboard transmitter. The ADS-B out provides real-time positioning information to air traffic controllers. This information is often reliable and accurate than the conventional radar-based system. With this real timely and accurate information, aircraft positioning and separation will be done with much timing and precision. On the other hand ADS-B in is a reception by the FIS-B and TIS-B data and other ADS-B data such as direct communication from nearby aircrafts.
The ADS-B’s air-to-air services are supplemented by the TIS-B, the TIS-B provides a comprehensive situational awareness of the cockpits of all traffic identified by the ATC system. The TIS-B service is a vital service for the ADS-B link in air space given the e fact that not all aircraft in the airspace are transmitting the ADS-B information. The ground TIS-B station transmits surveillance target information on the data link for targets that are not equipped. TIS-B uplinks are derived from ground radars for primary and secondary targets, ADS-B systems for targets equipped with different ADS-B link and systems for targets on the airport surface.
FIS-B on the other hand handles information regarding weather conditions and relays text, graphics and similar information to the aircraft. The system is quite different from the ADS-B since it requires external sources of data that is external to the broadcasting unit or the aircraft. It also has different performance requirements which include periodic broadcasting. This service will be provided after the UAT link in the United States in areas with ground surveillance infrastructure.
The ADS-B system is reliant on two major avionic components, a high integrity GPS navigation source and a data link (ADS-B unit). Several types of certified ADS-B data links exist however, the most common ones operate at 1090 MHz.the 1090 MHz is a modified version of the mode S transponder, or at 978 MHz (Weijun, Tong, & Wentao, 2012).
NextGen (Next Generation Air Transport system) and FAA (Federal Aviation Administrations) modernization of the aviation industry will only be brought about by the complete overhaul of the radar surveillance system. With the adoption of the ADS-B system the modernization initiative will be achieved. The system improves and creates better aircraft visibility at a relatively lower cost than the previous systems. Its equipment is designed and built to meet one of two sets of the US government standards the DO-269B and DO-282B (Allen, Jones, & Chartrand, 2012).
With the ADS-B the aircraft determines its own position using GNSS and periodical broadcasts through radio frequency. This technology was selected as part of the Next Generation Air Transport system and the European CASCADE program this is due to its integral nature and its room for flexibility. The system has the capability to provide surveillance services even in areas with no radar and can even enhance existing Radar services by providing greater target accuracy and higher update rate. Additionally, it has the capability to provide a cockpit display of traffic information hence allowing airborne collision avoidance (Weijun, Tong, & Wentao, 2012).
ADS-B is expected to offer high efficiency and environmental awareness and increased safety to air traffic controllers and the pilots at a lower cost than the current radar system. The uncertainty on the future of the system has been reduced by the final ruling by the FAA, thus products are being developed for all price ranges. With the maturity of the technology, there is more availability of the equipment’s hence generating more benefits to the general aviation users
There are several benefits attributed to the use of ADS-B system to both pilots and air traffic control. The use of the system improves the safety and efficiency of flights. With the use of ADS-B the pilot can view traffic information that surrounds the aircraft, hence helping in management and control of traffic. Aircrafts that are equipped with UAT ADS-B can receive weather updates through the FIS-B, this is relayed to the pilot hence enabling him safely fly the aircraft. The ADS-B in technology allows broadcast of terrain overlay to the cockpit enabling the pilot to view this information. Additionally, there are no costs or subscription fees for the use of the weather services as it is in other inflight weather services (Alarcón, Nieto, & Carretero, 2013).
The use of ADS-B technology generally improves the safety of flying significantly, particularly with the improved situational awareness. Pilots can have a high degree of awareness of the situations in the airspace courtesy of the equipped cockpit that has detailed flight display of other traffic in the airspace. They can also receive important updates such as runway closures and temporary flight closures.
The system also allows improved visibility to the air traffic controllers who have more accurate and reliable monitoring of aircraft positions. With the use of this system both the controllers and the pilot have the same radar image allowing them to safely navigate the air space (Besada, de Miguel, Bernardos, & Casar, 2012).
ADS-B technology basically improves safety by providing increased VFR flight following coverage, cockpit final runway occupancy, real-time cockpit airspace display, real-time cockpit weather display and radar like IFR separation in non-radar airspace.
The system also enhances efficiency through reduced environmental impacts by providing accurate reports on the aircraft's position. This accuracy allows the controllers to guide the aircrafts into and out of crowded air space than was possible with other systems. This reduces the amount of time wasted waiting for clearance (Weijun, Tong, & Wentao, 2012).
References
Alarcón, J. F. A., Nieto, F. J. S., & Carretero, J. G. H. (2013). Aircraft used as a sensor for atmospheric behaviour determination. Practical case: pressure estimation using automatic dependent surveillance-broadcast. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 227(5), 778-797.
Allen, B. D., Jones, K. M., & Chartrand, R. C. (2012). Operational Improvements From the Automatic Dependant Surveillance Broadcast In-Trail Procedure in the Pacific Organized Track System.
Besada, J. A., de Miguel, G., Bernardos, A. M., & Casar, J. R. (2012). Automatic-dependent surveillance–broadcast experimental deployment using system wide information management. International Journal of Microwave and Wireless Technologies, 4(02), 187-198.
Weijun, P., Tong, C., & Wentao, C. (2012). Automatic Dependent Surveillance Broadcast Simulation Training System. In Advances in Technology and Management (pp. 451-457). Springer Berlin Heidelberg.
