UAS Communication Systems and Data Links 2

Question 1

The 5.8 GHz frequency band is most commonly used for which function in UAS systems?

Accepted Answer

Analog or digital video downlink (FPV transmission)

Answer

The 5.8 GHz band is commonly used for video downlink (FPV) because its higher frequency supports greater bandwidth needed for video, though its range is shorter than the 2.4 GHz C2 band.

Question 2

In UAS communications, what does 'link budget' describe?

Accepted Answer

The accounting of all signal power gains and losses across a communication link to determine reliability

Answer

A link budget tallies all gains (transmitter power, antenna gain) and losses (path loss, cable loss, atmospheric absorption) to determine whether the received signal will be strong enough for reliable communication.

Question 3

Which antenna type is best suited for UAS ground station use when the aircraft may fly in any direction from the operator?

Accepted Answer

Omnidirectional antenna

Answer

An omnidirectional antenna radiates and receives signal equally in all horizontal directions, eliminating the need to point the antenna at the aircraft as its bearing changes during flight.

Question 4

What is the primary operational impact of RF interference on a UAS control link?

Accepted Answer

Degraded or lost link reliability, potentially causing loss of control

Answer

RF interference from devices operating on the same or adjacent frequencies degrades signal quality, which can cause control dropouts or complete loss of the command link, risking loss of aircraft control.

Question 5

What is the purpose of a 'failsafe' function in a UAS communication system?

Accepted Answer

To execute a pre-programmed response (e.g., return-to-home or land) when the C2 link is lost

Answer

Failsafe functions define automatic aircraft behaviors — such as hovering, returning to home, or landing — that activate when the C2 link is lost, preventing the aircraft from flying away uncontrolled.

(UAS) Unmanned Aircraft Systems Certified Practice Test

(UAS) Unmanned Aircraft Systems Certified Practice Test

UAS Communication Systems and Data Links 2