"David J Taylor" <[email protected]> writes:
>Richard B. Gilbert wrote: >[] >> That is what a "site survey" is. The GPS determines its location a >> few hundreds of times over the course of a day and does a "least >> squares" calculation to get a reasonable approximation of your >> latitude and longitude. >> >> Cellular phone base stations do a more extended site survey, thirty >> days instead of one. This gives them a MORE reasonable >> approximation. When I did my site survey (24 hours) the locations >> plotted a locus about >> 300 feet long in an East-West direction and with a width of about >> thirty feet. >> If I had had the patience and if I had required sub microsecond >> accuracy I could probably have trimmed that locus further. . . . . >> >> It is enough, for me, that my little herd of computers agree as to >> approximately what time it is. >Thanks, Richard. I took your "You do need to run a "site survey"" as >something rather more involved than letting your GPS just sit there. >For me, a few milliseconds is good enough, but I always want to do >better.... a) Don't run Windows. b) Don't run Windows. c) I get roughly 2us accuracy. That is about 1000 times better that you desire. (again a Garmin 18 LVC receiver with PPS running onto my parallel port with my own interrupt service routine on a Linux system.) >Cheers, >David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
