Re: GPS reciever for cubetruck

[Greg Troxel <gdt%lexort.com@localhost>]

Brad Spencer <brad%anduin.eldar.org@localhost> writes:

> Depends what you want to do with it, but gpsd may have trouble for you.
> The last I looked NetBSD does not support the IOCTLs required to get the
> PPS signal into it ...  Linux has an unusual ability in this matter.  If
> you are looking to just get NEMA serial data then gpsd should be ok.

Linux implements TIOCMWAIT that is not part of the RFC.  gpsd is
defective in that it depends on this beyond-RFC behavior, in the typical
Linuxy style of coding to the development system rather than the
standard.  It's probably not super hard to fix.

The PPS support in ntpd works fine.

However, most USB-attached GPS receivers do not have PPS anyway.  A few
do, and there is actually kernel PPS support for this, although USB PPS
is limited to about 1 ms.