[time-nuts] OT - GPS and North
Mike Naruta AA8K
aa8k at comcast.net
Sat Nov 21 19:58:04 UTC 2009
Tom, this would be taking advantage of the
irregularities of the GPS receive antenna
to determine the orientation of the antenna.
For example, if the GPS antenna were a Yagi,
and it was pointed with the major lobe in
an Easterly direction, when you listen to
a satellite in the East, you know it's location
and you can observe a high signal strength.
A satellite in the West might have a low
signal strength, or be missing.
Now this thought experiment is loaded with
issues; for example, external attenuation,
multi-path, multiple lobes, small gain
differences, etc., but we're just having
fun here.
Mike - AA8K
Tom Van Baak wrote:
>
> Mike,
>
> The calculations tell you where on the globe you are. Correct,
> from this you can easily calculate angle and distance to either
> pole.
>
> But the receiver cannot "indicate" this angle. Meaning if you
> hold a GPS antenna in your hand you may know you have
> to aim 75 degrees and walk 5000 km to the North pole but you
> still have no idea how to turn around to take that first step.
>
> A static GPS receiver is a point device, not a pointing device.
> On the other hand a magnetic compass is a pointing device,
> not a point device. That's why some navigation units combine
> both.
>
> If you just want to travel then as Confucius say: journey of a
> thousand miles begins with single step. But if you want to
> reach a particular destination then journey of a thousand
> miles must begin with single step in correct direction. ;-)
>
> /tvb
>
>
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