What is a Ground Station and basics of a Data Link
The first hours after a Natural disaster are the most critical, which means that rescue missions must be quick and efficient. Unmanned Aerial Vehicles, commonly known as Drones, are being used in rescue operations.
They have to gather lots of information that must be delivered in a Ground Station to be processed, stored and sometimes shown on a screen for the right person to see and analyze. A Ground Station is typically a radio station with a software application running on a computer by which the UAV can be controlled and all the data processed. A GS can be divided in two segments. One to control the drone, and the other one to process the data provided by the drones.
The information that is sent by the drones must be reliable and accurate. For that reason communication can be considered the most critical subsystem in UAV systems, and this is where the Data Link comes into play.
The Data Link allows communication and enables the transfer of data between a drone and the GS. There are generally three types of Data Links used for UAV communication. The first one is called Line of Sight (LOS) which can use different frequency bands. It needs two units (drone and GS) with directional antennas and allows point to point high speed communication. The second one is the Beyond Line of Sight (BLOS) Data Link which uses satellites so links are usually made at microwave frequencies and the communication distance is greater than in the case of LOS. Finally, the third type of Data Link is the Technical Data Communication one that allows simultaneous communications and includes secure data transfer features among other capabilities. Moreover, it requires lower bandwidth than other Data Links.
Generally, Data Links suffer from power attenuation, Doppler effect which affect the spectral efficiency, and from many loses due to the channel characteristics. In addition to this, there are important requirements for this type of links such as long distance and high speed. That is why designing Data Links for UAVS (Unmanned Aerial Vehicle Systems) is much more challenging than designing other wireless links.