(Nathan Young) writes:

It is probably a 1 or 2 sec update rate. That is often enough to
detect and display heading changes of a degree or two (as long as bank
angle is kept reasonable). The 'lag' is roughly equivalent to the
update rate. Ie, the GPS updates every second, and is showing you
position, heading, velocity derived from the t and t-1 epoch.

The reason I'm skeptical is that the mag compass also works fine for
holding heading in smooth air with very shallow turns: it doesn't go
to hell in a handbasket until the air gets rough, precisely the same
time the update lag in a handheld GPS could potentially also make it
difficult to use. That's why I'm interested in hearing from people
who've used it successfully in rough air, preferably at night (where
there are fewer visual cues like shadows moving over the panel).

Note that I love GPS's -- so much so, that I collect GIS data just for
fun, and have even hacked a way to get DAFIF data into a Magellan 315
from Linux.


All the best,


David