[Xastir] GPS settime

[Curt, WE7U]

On Mon, 22 Mar 2004 spqr at kc9asi.cjb.net wrote:

> It looks like there should be a call to ENABLE_SETUID_PRIVILEGE (main.h)
> before and a call to DISABLE_SETUID_PRIVILEGE (main.h) after the call to
> settimeofday() in gps_data_find in gps.c in xastir/src
>
>
> I am running xastir 1.3.0.  Sorry if this has already been fixed.

It hadn't been fixed.  Must be a feature that few people actually
use.  It's been fixed now in CVS, but won't be available on anon CVS
until it syncs up with the devel CVS server (a few hours).

Thanks for pointing this out!


> Enhancement opportunity: knowing the "accurate" time, based on GPS data,
> and the "inaccurate" system time, xastir could use the gps time (or system
> time + offset, based on what the difference is between gps and system),
> so that even if people don't want their computer's time to be right, the
> transmitted time is right.  This will introduce many problems.  This should
> probably not get implemented yet.

Since many clients and even findu ignore the transmitted time, it
would probably not be worth doing just on that basis alone.

If you really want accurate time on your computer, you use ntp to
hook up to an internet ntp server, or ntp hooked to a local GPS,
which will gradually shift your time until it is accurate, and keep
it more accurate even if you lose your time source periodically.

The way we do it is really a hack, as we bump the time all at once,
which can play havoc with things if the time shift is too much.

--
Curt, WE7U			    archer at eskimo dot com
Arlington, WA, USA		http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"