> Or the other way around. =A0Have the copter emit pulses and multiple rece=
ivers
> scattered around at known fixed locations pick up the pulses and a master
> processing system compares the received times to find position. =A0Ultras=
ound
> should work for this.

Yes, as far as I remember the concept is similar to old "Method for
determining artillery position". The problem can be reflections from
walls and other surfaces.

--=20
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