On Thu, Apr 24, 2008 at 9:14 AM, Kipton Moravec <[EMAIL PROTECTED]> wrote: > I am designing a system with a GPS module, and started looking at all of > the things it could do, including time. > > Since you folks are all interested in time, I was wondering which of two > products would be of interest to you. > > 1. A GPS module with the ability to expand the serial port to more than > 10 to allow you to use the NTP NEMA driver. The time pulse would be > accurate to about 30 nS RMS. Retail cost about $100.
yes. although i'm wondering where you're going to get such a non-crappy chip. Also, will it output raw measurements (CP/PR/D)? While you're at it, could you mount this on a (mini)?pci card with a dual-port UART - plug it in, it looks like 2 more com ports, but then you can use one port as your time source and the other port for "control" purposes. > 2. A time server with 2 Ethernet ports, with GPS time reference, to > directly support between 50 and 100 users using GPS. Retail Cost about > $200 could be fun - depends on what's in it. > Both would be Stratum 1 by using the GPS (and later Galileo also) > Satellites. > > Any additional specifications? How much more would you pay for the > additional specs? > > Or is this not interesting enough for you, that I would be wasting my > efforts. my home time server is a soekris net4801 driven by a garmin gps18; pretty low-end, but internal diagnostics say that it's tracking within 1 usec of the garmin's PPS output. that's tolerable, considering the garmin is only specified to 1 usec accuracy, and the 4801 isn't really a marvel of computing precision. And the fact that it's ethernet-connected to the ass end of an ADSL line - there goes all my precision anyway. also, the soekris can support more than 100 users; i've seen 182 unique ip's today, and the day is barely half over. as i'm also a bit of a gps nut, i like the fact that i can run gpsd on my time server to get a view on how the GPS is performing, as well as being able to generate a sky view (http://gpsd.mainframe.cx/). For that matter, I like the fact that I can put perl/php/python on this machine and whip up little scripts as it need them. So a cute little low-power SBC would be neat, but I hope it's not too low-power... CK -- GDB has a 'break' feature; why doesn't it have 'fix' too? _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
