Introduction¶

The aim of this project is the design study of a Telemetry and Telecommand (TM/TC) link between small aircrafts (ie TB20) and an antenna on top of ISAE building. There are different aspects in this work:

• regulatory aspects : we must find a frequency band, either license-free or requiering rights of emission
• link budget aspects : some parameters can be adjusted to reach the wanted performance
• flight constraints have to be considered in the choice of the equipment to allow a full time link

To summarize the system design constraints, we can fill the mission statement below:

In order to define the video bit rate required for our application, knowing the aspect ratio (AR=1,78) quality of the encoded video (L=720p) and its frame cadence (FPS=12), we used the following formula:

Bit rate = FPS*5,0692 * L ^1,391 /(1000*AR)

So

Bit rate=322 Kbps

As the link will allow video transmission, we will need an adapted encapsulation protocol, so we must take into account extra bits: we decide to define a bit rate of 500 kbps.