Figure 11-135.  Low power requirements allow remote ADS-B  stations with only solar or propane support. This is not possible with  ground radar due to high power demands which inhibit remote area  radar coverage for air traffic purposes.  Figure 11-136.  ADS-B OUT uses satellites to identify the position aircraft. This position is then broadcast to other aircraft and to ground  stations along with other flight status information.  11-61 flight status information, i.e., location including altitude,  velocity, and time. It then broadcasts this information  to other ADS-B equipped aircraft and ground stations.  [Figure 11-136] Two different frequencies are used to carry these broadcasts  with data link capability. The first is an expanded use of the  1090 MHz Mode-S transponder protocol known as 1090 ES.  The second, largely being introduced as a new broadband  solution for general aviation implementation of ADS-B, is at  978 MHz. A 978 universal access transceiver (UAT) is used  to accomplish this. An omni-directional antenna is required  in addition to the GPS antenna and receiver. Airborne  receivers of an ADS-B broadcast use the information to plot  the location and movement of the transmitting aircraft on a  flight deck display similar to TCAS.  [Figure 11-137] Inexpensive ground stations (compared to radar) are  constructed in remote and obstructed areas to proliferate  ADS-B. Ground stations share information from airborne  ADS-B broadcasts with other ground stations that are part of  the air traffic management system (ATMS). Data is transferred  with no need for human acknowledgement. Microwave and  satellite transmissions are used to link the network.  For traffic separation and control, ADS-B has several  advantages over conventional ground-based radar. The first is  the entire airspace can be covered with a much lower expense.  The aging ATC radar system that is in place is expensive to  maintain and replace. Additionally, ADS-B provides more  accurate information since the vector state is generated  from the aircraft with the help of GPS satellites. Weather is  a greatly reduced factor with ADS-B. Ultra-high frequency  GPS transmissions are not affected. Increased positioning  accuracy allows for higher density traffic flow and landing  approaches, an obvious requirement to operate more aircraft  in and out of the same number of facilities. The higher degree  of control available also enables routing for fewer weather  delays and optimal fuel burn rates. Collision avoidance is  expanded to include runway incursion from other aircraft  and support vehicles on the surface of an airport. ADS-B signal ADS-B signal Ground transceiver Conventional data networks GNSS position data Aircraft broadcast position, Altitude, Speed, etc.