On Tue, August 1, 2006 13:16, Ulrich Bangert said: > Poul-Henning did already give the answer. However i am not very happy > with the formulation
I do like Poul-Hennings forumulation better... Lets go back to your orginal formulation >> >> Note that any gps receiver can not be really good for >> >> timing and navigation at the same time, so all navigation receivers >> >> make bad timing receivers. I know one country where the national timing laboratory uses the same make/model GPS receiver as the cadastre service. There are probably differences in which SW options are activated -- surveying guys might have less interest in external frequency input/output. Here both the guys defining national time AND the national geografic reference system can use the same receiver. Most navigation receivers are surely "bad" timing receivers, but NOT ALL. >> In other words, it has nothing to do with the receiver, it's >> about what you ask it to do. > > because > > a) I never saw a navigation receiver featuring a "position hold" mode Have you seen a DGPS-base station receiver? They are also in "position hold" mode, even if its for a slightly different purpose. DGPS base functionality is always (anyone with a counter example? ;-) ) an expensive software option for a normal "navigation" GPS receiver. > b) I never saw a timing receiver featuring a "navigate forever" mode. > Everything that i had in my hands had a "automatic site survey" mode > after which it would return to "position hold". That's why i think the > formulation that it depends on the receiver's primary purpose is not > that wrong! Motorolas, now ancient, Oncore VP was used as timing receiver, it could do DGPS corrections -- in a motorola specific format, it could also run in a normal navigation mode. Ofcause this is not at the same instant in time! To get a good timing receiver we want a 1PPS with low jitter. That is most probably not a priority for high volume non-timing GPS receivers. But besides the 1PPS-hardware limitations, I do not see why a good navigation receiver, could do good in timing applications. -- Björn _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
