Hi You should get repeatability better than 10M. Under good conditions it should be below 1M.
You may have a multipath issue. What is your elevation mask set to? I suspect it's to low for your location. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Nelson Sent: Thursday, January 24, 2013 11:14 AM To: [email protected] Subject: [time-nuts] Lady Heather survey accuracy I hesitate to ask this question on here since it's perhaps more one for position-nuts rather than time-nuts. My excuse is that it involves a Thunderbolt ;-) I've been a happy user of a Thunderbolt for a while as an accurate time and frequency source but until recently I hadn't got round to mounting it in a proper enclosure with its PSU and finding a permanent home for the result in the office. Having done so I asked Lady Heather to carry out a 48h 'precision survey' and got a result which although close to that done when I first acquired the unit was about 10m different. I then carried out two further surveys which gave similar disparate results. LH reports latitude and longitude results to eight decimal places, which in principle suggests centimetre accuracy. I don't know enough about the finer points of GPS to know whether this is actually achievable over a 48h period but the results I'm seeing suggest that it's not. So the question amounts to this -- how reliable is the position produced by LH after a 48h 'precision survey' and what level of accuracy is achievable in practice? I'm guessing it's more like four places of decimals than eight. John _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
