This is a question that we often get, as operators of Unmanned Aerial Vehicles (UAV) or more commonly drones would like to use an indoor repeater to provide the live GNSS signal in indoor areas where they would like to fly their drone. UAV’s or drones use the GNSS signal for situational awareness, determining its position and navigating and obviously in an indoor arena or space you will lose the outdoor native GNSS signal due to the building blocking the signal, so flying the drone will become challenging.

Today drones are being utilized in many different applications, and they have brought lots of improvements and enhancements to various tasks that previously required a multitude of different equipment and personnel. When you move indoors, or inside tunnels or underground you will lose the live GNSS signal or at best you may get weak and spotty signals inside a building through skylights or windows.

So why not install a GNSS Repeater to provide a live GNSS signal in an indoor area to enable flying the drone indoors? When you lose the GNSS signal or experience reduced signal strength because of structural objects blocking the signal the situational awareness is lost either completely or partially. This will cause the drone to lose the capability to navigate without human guidance or can cause the drone to crash. The operators can fly certain drones “manually” using cameras providing the visuals back to the operator via a radio link.

The problem with using a repeater to provide the live GNSS signal indoors to operate a drone is that even if the repeated signal is the same live signal as outdoors it is the live outdoor signal as seen by the outdoor receiving antenna. In other words, the indoors repeated GNSS signal will always have the same fixed positional location of the outdoor receiving antenna, no matter how much the drone moves around. The coordinates will not change based on how the drone moves, it will constantly be the fixed lat., long., and elev. of the outdoor receiving antenna up on the roof of the building. So, the drone will become puzzled why the location data stays the same however it moves around as though it would be stationary.

In conclusion GNSS repeaters do not provide the means to navigate inside buildings, tunnels, or underground as the repeated signal always provides the same fixed location of the outdoor receiving antenna. The live GNSS signal will be good for testing and calibrating but not so much for flying the drone and navigating indoors.