How different is aviation GPS?

I have not seen the term "form-factor" used before.

It's marketspeak for "shape".

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

In a previous article, B A R R Y said:
I'm in CT, so being right on the east coast, and not right against the
Canadian border might have a positive effect. AFAIK, the two special
satellites are over the Atlantic and Pacific.

According to
http://gps.faa.gov/programs/waas/for_pilots.htm
both of them are in the middle of the Pacific now. And when they get a
third one this fall, it's still going to be over the Pacific as well.

--
Paul Tomblin http://xcski.com/blogs/pt/
A male pilot is a confused soul who talks about women when he's flying,
and about flying when he's with a woman.

"Montblack" wrote in message
...
based on the satellites' "predictable" orbits.... g

Ok. No clue.


Montblack

This is know as the 'ephemeris'.

The term has been around in the engineering world for 40+ years that I
know of. It really has to do with the shape of the package and its
dimensions.


Peter Duniho wrote:
"Montblack" wrote in message
...
("Peter Duniho" wrote)
It's too bad, because I really liked the form-factor of the smaller GPS.
I live in a cave.

I have not seen the term "form-factor" used before.

Sorry...I've seen the term in a variety of industries, but I admit it's
probably not yet part of the common vernacular. It simply means how the
device is packaged, and how that packaging affects the user-interface and
utility of the device.

Basically, I just mean that the smaller GPSs seem "handier". But they don't
perform as well, so I wound up with a larger one anyway.

Pete

B A R R Y wrote:
Stubby wrote:

A friend bought a 60CS recently and we noticed that my old Garmin-12
got better reception and seemed more accurate. We called Garmin and
the fellow we talk with was surprised because both units use the same
chips inside!

I'm totally surprised, and a tad skeptical for a few reasons.

The 12 used a patch antenna, similar to the eMap and eTrex series.
My -12 does not have an external antenna.

Furthermore, the 12 series didn't use WAAS. Is something wrong with
your 60CS? G
Actually, it belongs to a geocaching friend. The reason we call Garmin
is because it appeared that something was wrong with the -60CS. If -12
and the -60CS actually have the same chip inside, they both would have
WAAS. In practice, I think they have the same accuracy.

Also, the old -12 is a lot easier to enter data into. But I do like the
whizzy color on the -60CS.

OK. Just how does a standard surveryor's equipment measure distance.
Does it count interference fringes?


Jim Macklin wrote:
You also attach a thermometer to the tape because there is a
correction for expansion. If the tape was supported by the
ground, a tension of 10 pounds was required if I remember
correctly.


"Paul Tomblin" wrote in message
...
| In a previous article, Stubby
said:
| I had my property surveyed and asked what the accuracy
was. The
| surveyor replied that 0.1 foot is the standard for most
applications and
| 0.01 foot is required for commercial, high-precision
applications.
| They use GPS (DGPS??) but I don't know how.
|
| You need a better surveyor. When I was doing road
construction layout, we
| were expected to get the marks within 5-7 millimeters.
And when they
| actually did the construction, they were allowed to be
within 2-3
| centimeters. (You've heard the expression: measure with a
micrometer,
| mark with chalk, cut with an axe.) Legal surveyors were
supposed to be
| *far* more accurate than us. For instance, we just held
the chain (that's
| the "measuring tape" to you) or laid it down on the
ground. Legal
| surveyors had a special device to make sure they were
holding exactly the
| right amount of tension on the chain because that's what
it was calibrated
| for.
|
| --
| Paul Tomblin
http://xcski.com/blogs/pt/
| ALL programs are poems, it's just that not all programmers
are poets.
| -- Jonathan Guthrie in the scary.devil.monastery

wrote in message
oups.com...
Matt Barrow wrote:

Aircraft GPS systems are accurate to about 30 feet; how well do you think
that would work if your building a bridge, or more importantly, a tunnel?


If I was owner, I'd end up with two tunnels for the price of one

One tunnel, two lanes. :~&

wrote in message
oups.com...
Peter Duniho wrote:

That is correct. The presumed 50 meter accuracy is constant throughout
the
flight. It's not as though it's additive for each waypoint (or worse, as
a
continuous function along the flight). Though frankly, even if it were,
you'd only be off by 500 meters after 10 waypoints which is still "no big
deal".

Now I know why planes occasionally land on the wrong runway in IFR
conditions )

As someone already mentioned, the error is not cumulative. Then, too,
approach GPS is a different animal from enroute.

Now I know why planes occasionally land on the wrong runway in IFR
conditions


You do? I don't. In fact, I don't think they do. That happens in visual
conditions.

--
Thomas Borchert (EDDH)

Paul Tomblin wrote:

According to
http://gps.faa.gov/programs/waas/for_pilots.htm
both of them are in the middle of the Pacific now. And when they get a
third one this fall, it's still going to be over the Pacific as well.

Look at the page you cited one more time.