ADS-B Surveillance System Performance With Small UAS at Low Altitudes

Abstract

The projected expansion of SUAS operations in the U.S. has motivated the examination into how these aircraft will "see and be seen" by other aircraft operating in the U.S. National Airspace System (NAS). One proposal is that the SUAS use a system compatible with aviation, such as the Automatic Dependent Surveillance -Broadcast (ADS-B) surveillance service. This analysis intends to highlight the impact on the Universal Access Transceiver (UAT) ADS-B system performance from a shared-use operation by SUAS. The purpose is to examine various operational scenarios and estimate UAT's ability to continue to support existing air traffic management air-to-air and air-to-ground applications. The study extended prior research and examined a multitude of scenarios from low to high stress cases. The analysis indicates the key parameters are SUAS ADS-B transmission power and SUAS traffic density. These two parameters can be balanced to attain an acceptable demand on the UAT in areas of potentially high SUAS concentration while still providing safety and utility to all aircraft.

When UAVs coexist with manned airplanes: Large‐scale aerial network management using ADS‐B

“…M a =100:100:400 airplanes and the corresponding UAVs are approved to fly (as well as sending the ADS‐B messages). Figure illustrates the average status update interval with the required probability of 95% . It can be seen that the update interval of a low‐power UAV is very close to the required 3 seconds.…”

“…These UAVs send the ADS‐B signals as the manned airplanes equipped with ADS‐B during flight. To reduce the interference, the transmission power of UAVs (such as 0.01 to 1 W) should be much lower than that (75 W to 500 W) on airplanes. One manned airplane may transmit multiple kinds of signals, eg, ADS‐B, secondary surveillance radar (SSR), TACtical Air Navigation, Traffic Collision Avoidance System (TCAS), Aeronautical Radio Navigation Service (ARNS), etc.…”

“…Generally, the transmitting power of the ADS‐B on manned airplanes is 75 W to 500 W with a maximum transmission range of 500 km; while that of the ADS‐B on UAVs is much lower (eg, 0.01 W to 1 W) to reduce the interference. With the signal propagation model it is easy to obtain that UAVs are visible to an ADS‐B receiver (on a helicopter, the ground, or a manned airplane) from several kilometers away.…”

“…Theorem To meet the status update requirement of the FAA, the probability ( p r ) that one ADS‐B message can be correctly received should satisfy p r ≥ 41 % .…”

“…Existing works on studying the ADS‐B technology on UAVs focused more on a single device or a small‐scale fleet, such as references . NASA has been testing the ADS‐B technology in its latest UTM system for small‐scale UAV network management .…”