David Megginson wrote in message ...
(Nathan Young) writes:

Your statements that the GPS lags dangerously are inaccurate (at least
wrt to the Garmin 295). The HSI updates quick enough to show heading
changes of a few degrees as long as the bank angle is kept under a
reasonable amount, say 10 degrees. Easy to do in smooth or light
turbulence.

The lag is time, not heading. How long does it take a heading change
to register? I've heard that it's at least a second on the 196, and
sometimes two seconds or more on the 295, but I don't own either.

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.

Most GPS engines are running faster than the display rate. GPS
engines from 5-10 years ago operated on 1 or 2 sec position updates.
Newer engines are more granular, with 5Hz operation being common.
That means the display data shown is typically derived from the
velocity/heading calculated from the time 1 and 1.2 seconds in the
past.

-Nathan