# <center><i class="fa fa-edit"></i> UAV Communication System </center>

###### tags: `Drone Communication`

::: info
**Goal:**
- [ ] Introduction
- [x] Drone communications
- [x] Satellite Communication
- [ ] Radio Signal Communication
- [ ] Internet

:::

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## Introduction
An unmanned aerial vehicle (UAV) is an aircraft, commonly called a drone, which is a partially or fully autonomous system that receives commands or missions from an operator or pilot. Nowadays, UAVs are a future device for several applications. People are conscious of the high potential for drones to be used in various fields. For instance precision agriculture, surveillance, reconnaissance, mapping, and others. In order to have a remarkable system of drone, parts of the systems need to be improved for high-quality performances.

Autonomous drones need to communicate with an operator or pilot on the ground station. The drone will communicate wirelessly within specificied frequency provided. To establish reliable communication for drones; low latency, secure system, uninterrupted communication, coverage wide-area, and others are required to enhance the vehicle performance during the flight mode. Therefore, the communication system of UAV is an essential part of the drone system that need to be enhanced dynamically.

How does a drone communicate to the ground control station?

## Drone Communications
`source: https://link.springer.com/content/pdf/10.1007/s42452-020-2749-5.pdf`

The image above depicts the communications commonly used on various drones. There are three common ways to connect a UAV to a ground control station such as satellites, radio signals, and the internet. Each communication system has advantages depending on the needs of its implementation. For example, the UAV can communicate to GCS using satellite communication to have a stable connection during its flight. However, the systems are quite expensive and impractical for small-scale UAVs. On the other hand, radio control is practically used in short-range missions with limited data transmission bandwidth. Many studies overcome both problem statements by using communication via the internet. However, it raises new issues regarding the drone’s secure communication system.

## Satellite Communication

Satellite communication has long-range and wide coverages over remote areas. Satellite communication considers being used due to the long-range high latency link between a Ground Control Station (GCS) and a UAV. Long-range satellite communication requires parameters including data rate, bandwidth, bit error rate, availability, latency, security, power consumption, cost, and weight. They divide into the forward link (FL, from the ground station to the UAV) and the return link (RL, from the UAV to the ground station). Each path has an uplink (UL) to the satellite and a downlink (DL) from the satellite.

According to the latency, satellite communication has round-trip latency depending on the choice of orbit.


Round-trip latency is the time delay for a signal to travel from the UAV to the ground station and vice-versa.The geostationary Earth orbit (GEO) is useful because the satellite remains at the same point in the sky, so does not require tracking. However, low latency can be achieved by low Earth orbit (LEO) satellites (Fig. 4). Based on [PX4 documentation](https://docs.px4.io/master/en/advanced_features/satcom_roadblock.html), satellite communication can be applied on a UAV using RockBlock as the service provider for the Iridium.

The (Iridium, 2015)NEXTservice in 2017 has a high data rate of 1.5 Mbps forward link and 512 kbps return link. It uses LEO satellites to reduce the latency and can be provided by (Aireon, 2015). In the future, the service could be upgraded to Iridium PRIME, which can offer 17 Mbps.

`source:https://docs.px4.io/master/en/advanced_features/satcom_roadblock.html `
`Source II: https://www.researchgate.net/publication/330739221_Satellite_Communication_System_Study_for_Unmanned_Autonomous_Aircraft_UAVs`

## Radio Signal Communication