On Mon, 2019-10-07 at 10:38 -0400, Neil wrote:
> Hi,
>=20
> How realistic would it be to locate an object on a field using signal=20
> strength?  I'm thinking the (moving) object would transmit (LoRa?) and=20
> there would be receivers around the field.
> At first pass, I'm thinking the transmitter would send numbers (changes=20
> each on each transmission), and the receivers can record the signal=20
> strengths when they receive each value, then correlate those values to=20
> get a location.
> I'm just not sure how realistic it would be to get the position of the=20
> object to within say a few feet.
> No, GPS is not a workable option for this.
>=20
> Cheers,
> -Neil.

With enough receivers, and some pretty fancy software, maybe.

RF is nasty, it gets reflected off everything, the reflections can lead
to one signal arriving over multiple paths, causing interference,
destructive or constructive. Depending on the frequency, lots of things
can absorb RF radiation.

Maybe at very low frequencies and moderate distances you might have some
luck, but probably not within a few feet.  In the low MHz range, there
aren't a lot of things large enough to be effective reflectors. Of
course, the ionosphere is one such thing, but the signal strength should
be a lot weaker than direct line of sight so you might make that work.
But low frequencies require large antennas, so I assume you are thinking
of Gigahertz or hundreds of Megahertz. In that case there are plenty of
land mines. Buildings, fences, cars, even airplanes make good
reflectors. Leaves are great at sucking up RF, and when you get into the
GHz range, even humidity can be your enemy.

Triangulation is much more likely to be successful, but even that can be
problematic.=20

--McD



--=20
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