I'm multimedia developer who is searching for a way to get GPS signal inside buildings/structures. Is amplification a reliable way to fix this GPS signal issue?
Will a "GPS Amplifier" work as perfectly as using GPS outside?
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The short answer is no.
By amplifying a GPS signal, you are creating a multipath situation. Instead of the proper signal path from the satellite directly to the receiver, you would be creating a triangle inequality (unless your amplifiers just happened to be exactly in line between each satellite and the receiver).
You might decide that having an imperfect signal inside the building is better than no signal at all. However, the bigger issue is that you'd be magnifying the multipath effects for any GPS receivers outside the building.
You should look at an alternate GPS-like technology, such as radio-frequency TDOA (time-difference of arrival).
GPS relies on trilateration to work. That is, the calculated distance from at least three satellites, to fix. So, for working exactly like in an outdoor GPS covered signal environment I doubt it will be feasible.
What you get with that repeaters, is that the indoor devices will get the position of the external antenna/receiver.¹. So if you have a big space and move inside it you will get the same position from the GPS.
So it will depend on your application if this is sufficient or not. One way it will work is like some repeaters within a big mine for example, so it will show some location points, but this is for legacy compatibility of the signal. If the devices are able to read the location from other types of signals a simple beacon transmitting a programmed location will work, and without any external antennas.
Note 1: the repeater inside the building will relay the exact co-ordinates of the outdoor antenna to the interior of the building - it will not provide co-ordinates for the repeater unit itself. From http://www.gps-repeaters.com