Falcon 8 UAV - Basic Training: Dealing with Electromagnetic Interference

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What is electromagnetic interference?

Electromagnetic interference is a disturbance in the radio frequency caused by an external source. This disturbance can cause errors or complete data loss. Electromagnetic interferences are caused by many things like cell phone towers, power lines, thunderstorms...

The Falcon 8 uses radio frequencies for GPS, communication with the MGS and the video link. In some cases, when flying next to a powerful source this can lead to loss of link or unexpected flight behaviour.

Electromagnetic interference:

Flying the Falcon 8 close to powerlines, cell towers, power transformers, or other areas that might have high electromagnetic interference can have severe effects on the GPS stability and/or the magnetic field sensor which may also cause GPS instability. 

It is not predictable how the Falcon 8 will exactly react around interference because it is dependent on:

  •  frequency
  •  modulation
  •  polarity
  •  directivity
  •  ... many more factors

The Falcon 8 is designed to compensate for errors caused by these interferences in most cases, but this function is not guaranteed in all situations. Therefore, the pilot needs to be trained on flying in height-mode and needs to be prepared to switch over to height-mode all the time when flying in such environments. 

Flying next to anything with more output then 100 W might have an impact on the electronics. If it is necessary to fly next to such a transmitter it is best to shut it down. 

Powerlines / cell towers:

In most cases flying close to powerlines or small cell towers does not cause any errors in the Falcon 8, but this is dependent on many factors so the pilot always needs to be prepared to switch over to height mode. 

When flying next to bigger broadcast towers there are some interferences to be expected, like connection dropouts or GPS interference. 

It is recommended to slowly work your way towards the transmitter, starting from a safe distance. If the directivety is known, and the job allows it, avoid flying directly into the radio link. 

It is important that the pilot is always alert, on the watch for unusual behaviour, and prepared to switch over and fly in height-mode.

How to react (when flying GPS-mode):

UAV starts drifting

  • Switch to height-mode and control the UAV in height-mode.

UAV does not seem to react to the control inputs of the pilot (data link seems OK)

  • Switch to height-mode and control the UAV in height-mode.  

UAV is swiftly flying away from its current position during vertical take-off

  • Switch the UAV to height mode and continue take off.
  • Go to a safe distance from the ground and other obstacles quickly.
  • Control the UAV in height mode.

How to react (when flying GPS- or height-mode)

UAV performs strong changes in altitude, which have been not commanded on the MGS.

  • Switch to manual-mode and perform a controlled landing.
  • Get help from Support to analyze the cause. 

Loss of data link connection between UAV and MGS.

  • Check the antenna orientation.
  • Try to shorten the distance to the UAV by walking towards it. The link loss procedure that has been chosen when starting the system will automatically start.
  • As soon as the link is re-established you can take control again. 

Simultaneaus loss of GPS reception, and data link connection, between UAV and MGS

  • Check the antenna orientation.
  • Try to shorten distance to the UAV by walking towards it.
  • As there is no GPS signal, when the link loss procedure starts, it is impossible to locate the home position and the system will perform a direct landing.