Peter Duniho ) wrote:
: GPS increases the chances of collision, by reducing the average error. But
: the issue did already exist with VOR navigation. Keep in mind that GPS
: error is still going to be on the order 10 to 30 meters or so, just from the
: position information standpoint, and then on top of that you still have the
: problem of the airplane being kept exactly at the intended position (even
: with an autopilot, there's going to be some slop, and not all pilots are
: using autopilots in conjunction with their GPS navigation).

The GPS error you have quoted is relative to a fixed point on the ground.
Most modern cheap GPS recievers in the same region looking at the same
sats with differential corrections are within meters of each other
and with good processing can produce a relative position within a few
inches.

The way to deal with this is to simply move the GPS course .1 nmi
to the right. This means if your doing a 90 degree turn over a VOR
using a GPS, you should make your turn .14 nmi away from the VOR
and you should be able to see it out the left window.

At this point it won't matter much considering the GA autopilot slop
but things could change in the future and now is a good time to
start putting these things in place.

but there are more an more aircraft flying in the skys that don't
but things could change in the future and now is a good time to
start putting these things in place.

-tim
http://web.abnormal.com