GPS on aircraft

I often take my GPS with me when I am on a commercial plane as I also
use it in my own plane.
I always have people around me come look at my screen to see where the
plane is...

On a recent trip, I said something to one of the Pilots on the way out
about the GPS. He said my GPS (ala Delorme on my laptop) was probable
more accurate than the 10 year old instruments on the aircraft.

the Delorme software cost onlu $100 at Officemax or Fry's Electronics
I have both the street atlas version and the topo version.

the GPS told me at what altitude, heading and also the aircraft speed


--
JOHN

888-5-analon (888-526-2566)

computers (unix admin), chemistry, and Freggs too
I make it work. X-windows, not MSW !

jamoran writes:

On a recent trip, I said something to one of the Pilots on the way out
about the GPS. He said my GPS (ala Delorme on my laptop) was probable
more accurate than the 10 year old instruments on the aircraft.

If there is no GPS on the aircraft, that may be true, for long distances.
Inertial systems are extremely precise after initialization, but since they
rely on dead reckoning, they drift substantially over long periods. Radio
aids are more accurate for landing guidance than GPS, but for the rest of the
flight, nothing is more accurate than the inertial stuff, and the inertial
stuff drifts, so at the end of a 10-hour flight, even a consumer GPS may be
more accurate.

the GPS told me at what altitude, heading and also the aircraft speed

The heading and speed are probably reliable. The altitude will be much less
so (not nearly enough for navigation, as a general rule).

jamoran wrote:

about the GPS. He said my GPS (ala Delorme on my laptop) was probable
more accurate than the 10 year old instruments on the aircraft.

Not when used from a passenger seat. From a window, you have a very "two
dimensional" view of the sky, so the 3d calculations have far lower
accuracy because they do not have enough "3d" distance between
satellites. It also takes longer for the unit to lock in (unless you
estimate your position and force it into the GPS to help it make sense
of the few signals it is getting.

Once you have a lock, the speed, heading and postion are accurate from
an airplane's point of view. (it isn't as if you're looking for a needle
in a haystack, by the time you've looked at your current position, the
plane has moved MANY metres away already)

"jamoran" wrote in message
.. .
I often take my GPS with me when I am on a commercial plane as I also use
it in my own plane.
I always have people around me come look at my screen to see where the
plane is...

On a recent trip, I said something to one of the Pilots on the way out
about the GPS. He said my GPS (ala Delorme on my laptop) was probable more
accurate than the 10 year old instruments on the aircraft.

the Delorme software cost onlu $100 at Officemax or Fry's Electronics
I have both the street atlas version and the topo version.

the GPS told me at what altitude, heading and also the aircraft speed


I also have the Delorme and I also managed to configured it to work with MS
Streets and Trips. I've used it on Carnival cruise ships on the Mississippi
River and Gulf of Mexico.
http://public.fotki.com/apjung/vacat.../dsc02167.html
http://public.fotki.com/apjung/vacat.../dsc02340.html

I didn't use it for my recent flight from New Orleans to Taipei because I
got a TomTom One during Black Friday 2007. I kept it powered with Energizer
Energi To Go.
You just can't fit a regular laptop on a tray table in Steerage.
http://tinyurl.com/6zufnj


--
Andy P. Jung
Metairie, Louisiana U.S.A.
(on the Western side of the now infamous 17th Street Canal)
http://www.JungWorld.com/

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