rate of turn among other key relevant indications. Examples  of PFDs are illustrated in  Figure 5-45 . Synthetic vision provides a realistic depiction of the aircraft  in relation to terrain and flightpath. Systems such as those  produced by Chelton Flight Systems, Universal Flight  Systems, and others provide for depictions of terrain and  course.  Figure 5-46 is an example of the Chelton Flight  System providing both 5-dimensional situational awareness  and a synthetic highway in the sky, representing the desired  flightpath. Synthetic vision is used as a PFD, but provides  guidance in a more normal, outside reference format. In addition to a PFD directly in front of the pilot, an MFD  that provides the display of information in addition to primary  flight information is used within the flight deck.  [Figure 5-47] Information such as a moving map, approach charts, Terrain  Awareness Warning System, and weather depiction can all  be illustrated on the MFD. For additional redundancy both  the PFD and MFD can display all critical information that  the other normally presents thereby providing redundancy  (using a reversionary mode) not normally found in general  aviation flight decks.  Although standards for Automatic Dependent Surveillance  (Broadcast) (ADS-B) are still under continuing development,  the concept is simple: aircraft broadcast a message on  a regular basis, which includes their position (such as  latitude, longitude and altitude), velocity, and possibly  other information. Other aircraft or systems can receive this  information for use in a wide variety of applications. The  An ADS-B based system, on the other hand, would listen  for position reports broadcast by the aircraft.  [Figure 5-48] These position reports are based on satellite navigation  systems. These transmissions include the transmitting  aircraft’s position, which the receiving aircraft processes into  As an simplified example, consider air-traffic radar. The radar  measures the range and bearing of an aircraft. The bearing is  measured by the position of the rotating radar antenna when it  receives a reply to its interrogation from the aircraft, and the  range by the time it takes for the radar to receive the reply.  key to ADS-B is GPS, which provides three-dimensional  position of the aircraft. Figure 5-46. The benefits of realistic visualization imagery, as  illustrated by Synthetic Vision manufactured by Chelton Flight  Systems. The system provides the pilot a realistic, real-time, three- dimensional depiction of the aircraft and its relation to terrain  around it. Synthetic Vision Multi-Function Display (MFD) Advanced Technology Systems Automatic Dependent Surveillance—Broadcast  (ADS-B) XPDR 5537 IDNT  LC L 10:12:34 INSET PFD CDI XPDR IDENT TMR/REF NRST ALERTS VOR1  270 ° 2 1 1 2 4300 4200 4100 3900 3900 3800 4300 3600 3500 3400 3300 3200 3100 20 80 4000 4000 130 120 110 90 80 70 1 100 9 TAS 106KT OAT 6°C NAV1108.00  113.00 NAV2  108.00 110.60 134.000 118.000  COM1 123.800 118.000 COM2 WPT  ______  DIS  __._ $_{NM}$ DTK  ___$_{° }$ TRK  360° OAT 6°C Figure 5-45. Two primary flight displays (Avidyne on the left and Garmin on the right). 5-28