What is ADS-B
Automatic Dependent Surveillance-Broadcast (ADS-B) is the cornerstone of the FAA’s NextGen air transportation system. Basically it provides controllers and pilots with an aircraft's position, using GPS position information that is broadcast on either Mode S transponders or UAT’s (Universal Access Transceiver). Pilots will now be able to see real time position of other aircraft in their vicinity, the same information that controllers are seeing.
ADS-B stands for:
A utomatic No pilot or controller action required
D ependent It depends Global Navigation Satellite position input
S urveillance It provides "radar-like" surveillance to equipped aircraft and ATC
B roadcast It continuously broadcasts aircraft position and other data to any properly equipped aircraft and ground station.
Full Airspace Coverage ADS-B equipment can be installed in areas where it is not feasible to establish radar-based surveillance equipment. For instance, ADS-B equipment will be installed on oil platforms in the Gulf of Mexico, delivering substantial safety and efficiency benefits to air traffic flying over the area.
TIS-B Traffic Information Service-Broadcast. When fully implemented ADS-B equipped aircraft will be able to receive and display the position of all other ADS-B equipped aircraft in their vicinity, either through aircraft-to-aircraft transmission of position or through the rebroadcast of aircraft position from a network of 794 strategically located ground stations. ITT is currently on track to have the full US network of ground stations in place by the end 2013.
FIS-B Flight Information Service-Broadcast. UAT equipped aircraft with be able to receive transmitted flight information from 794 strategically located ground stations. Initial FIS-B data will include cockpit weather.
ADS-B Formats There are two current systems that will fulfill ADS-B requirements.
1090ES is a based on Mode S transponders. 1090ES (Extended Squitter) systems will ‘squitter’ TIS-B information which can be displayed by other ADS-B equipped aircraft. There is currently no provision for 1090ES to receive FIS-B information.
UAT (Universal Access Tranceiver) is a new and attractive alternative to 1090ES and provides the user with both TIS-B and FIS-B. Initial FIS-B information includes weather in the cockpit. This weather information is free to the user and will carry no subscription fees.
Sandia ADS-B solutions
1090ES for aircraft with Collins TDR94D transponders and Garmin 400W/500W navigators Sandia has the ADC 7-35-01 which allows the Garmin GPS to talk to the Collins transponder. This unit was developed in conjunction with a major helicopter operator. In addition to providing the interface from onboard GPS receivers to Mode S transponders, the SAC 7-35-01 is also a full function airdata computer.