UAS Communication Systems and Data Links

Question 1

What frequency band is most commonly used for UAS command and control (C2) links in consumer and commercial operations?

Accepted Answer

2.4 GHz ISM band

Answer

AM broadcast band (540–1700 kHz)

Answer

FM broadcast band (88–108 MHz)

Answer

HF shortwave band (3–30 MHz)

Question 2

What does the term 'C2 link' refer to in UAS operations?

Accepted Answer

Command and Control link between the ground control station and the aircraft

Answer

Camera-to-camera communication between multiple drones

Answer

Cloud-to-cloud data synchronization for mission logs

Answer

Cellular-to-controller backup communication channel

Question 3

What is the primary function of a telemetry downlink in a UAS system?

Accepted Answer

Transmitting real-time aircraft status data such as altitude, speed, and battery level to the operator

Answer

Transmitting live video from the camera payload to the ground

Answer

Sending navigation waypoints from the ground station to the aircraft

Answer

Establishing an internet connection for in-flight software updates

Question 4

Which phenomenon describes the reduction in radio signal strength as the distance between transmitter and receiver increases?

Accepted Answer

Free-space path loss

Answer

Doppler shift

Answer

Multipath interference

Answer

Antenna polarization mismatch

Question 5

What does RSSI measure in a UAS communication system?

Accepted Answer

Received Signal Strength Indicator — the power level of the received radio signal

Answer

Remote Sensor Signal Interface value

Answer

Radio Spectrum Safety Index for regulatory compliance

Answer

Real-time Status Signal Input from onboard sensors

Question 6

Why is Frequency Hopping Spread Spectrum (FHSS) used in some UAS control systems?

Accepted Answer

To improve resistance to radio frequency interference and unauthorized signal interception

Answer

To increase maximum data throughput for high-definition video

Answer

To reduce aircraft power consumption during transmission

Answer

To extend control range beyond the visual line of sight

Question 7

What primarily limits the effective range of a standard UAS radio control link?

Accepted Answer

Line-of-sight conditions and antenna gain characteristics

Answer

The battery capacity of the ground controller transmitter

Answer

FAA regulatory distance limits imposed by Part 107

Answer

Operating system software range caps built into the flight controller