If you are talking about using this with NTP. I don't know if you have a choice. The Trimble receiver is going to do whatever it is going to do when you power it up. Software running on a PC can perform a 24 hour survey and report the location but the "Type 29" driver in NTP has no way to tell the Trimble receiver what to do on power up. And there is no way to specify a location you have surveyed by some other means.
Perhaps the Trimble GPS has some way to program it's FLASH Rom with changed parameters but NTP only reads the packets. It does not send any. Can LH download a surveyed location r change the length of the survey? NTP can't do any of that Other NTP drivers such as the Type 30 Motorola driver are more flexible. Those alow you to specify a lat, long that was surveyed or have the receiver do a survey. The type-30 Motorola driver is a lot more configurable. But as was said, light travels about 30cm/nanosecond and NTP works in microseconds. So your location can be "off" by 1000 times 30cm before NTP will care. So 3 or 4 meters of location error will not matter and the 2,000 point self survey will be good enough. But if yo really so want nanosecond level timing, then you need to care about the survey On Sun, May 5, 2013 at 4:28 AM, Sarah White <kuze...@gmail.com> wrote: > On 5/5/2013 6:35 AM, Miguel Barbosa Gonçalves wrote: >> Hi fellow time nuts! >> >> I've recently bought a Trimble Acutime gold that will be used as a >> reference clock for a NTP server. >> >> This receiver has the possibility of averaging it's position before >> entering what Trimble calls the overdetermined clock state. The >> default is to average the position with 2000 fixes. >> >> What do you believe is a good number of fixes for the survey in this case? >> >> Cheers, >> Miguel > > Accurate position might be important. Light travels a distance of > something like 29.9792 centimeters per nanosecond > > You might find the results of this study to be helpful: > > http://www.syz.com/gps/gpsaveraging.html > > I myself did a sampling over a period of 1 million samples > (actually, it was a value of 2^20, not exactly 1 "million") > quickest it could have completed such a survey is 12+ days > > ... However, I had "masks" set for elevation, signal, etc. > (resulted in occasional periods when there was no "lock") > > I'm quite satisfied / happy with the results :) > > hope this helps? > --Sarah > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.