Can GPS Repeaters Provide Accurate Indoor Location?
If you’ve ever tried using GPS indoors, you know the frustration: signals are often weak or completely unavailable.
A GPS repeater system brings satellite signals inside, ensuring GPS-enabled devices maintain “sky view” and achieve lock while under cover.
Even though GPS was never designed for indoor use, there are many situations where access to live satellite signals is useful, desirable, or even critical — especially for emergency services and other “blue light” operations.
One thing a repeater cannot do, however, is provide accurate indoor location.
That isn’t meant as a negative point — repeaters are extremely useful across a wide range of applications.
In this post, I’ll explain how a repeater system works and what it can (and can’t) do.
How a GPS Repeater Works
A repeater system captures satellite signals via an outdoor antenna, passes them down a coaxial cable, and retransmits them indoors.
Devices can then “see” satellites and achieve lock even without a clear sky view.
Typical applications include:
Fire, police, and ambulance stations
Aircraft hangars (civilian and military)
Vehicle garages and depots
Testing and R&D facilities
PNT systems relying on GPS time
The main goal of a GPS repeater is signal availability — allowing devices to receive live GPS signals without stepping outdoors.
Why GPS Repeaters Can’t Provide Accurate Indoor Location
Imagine you’re outdoors using your phone’s mapping app.
As you move, your phone’s GPS receiver constantly recalculates its position based on signals received from multiple satellites.
Now step indoors, where a GPS repeater is in use.
As you move around, the main receiving antenna is no longer the one in your phone — it’s the fixed antenna on the roof.
Since that antenna doesn’t move, the location coordinates your phone receives stay constant.
As a result, your device will report its position as being at the outdoor antenna’s location, not where you’re actually standing inside.
That’s why repeaters are for signal continuity, not indoor positioning accuracy — and in most cases, that’s exactly what’s needed.
This case study describes how flying a drone indoors isn’t possible when GPS signal is received via a repeater.
However, for functional testing and keeping the device connected, a repeater is ideal.