GPS Time Sync

I'm wondering how difficult it would be to get a fairly acurate time synch independent of an ongoing internet connection.

www.blueunplugged.com/p.aspx?p=139587

I found this - which is dirt cheep (£17) and claims time accuracy to 1 microsecond (surely that's accessible or why quote it?). Plugs into the PC as USB dongle.

I gather that not all consumer GPS units generate the appropriate string for reading time. I also read that Windows isn't so hot with time accuracy anyway (if I recal from my DOS days calendar clock ticks at about 1/18th second but can't swear to that and tick rate could have improved since then). Also I have read comments indicating that USB is not a good protocol to perform synch over. All this pretty anecdotal however.

Am I barking up the wrong tree or can one get as good as it gets for Windows time synch on a budget and without internet? (and I acknowledge endorsement of Dimension4 internet sync by another poster or two some while back).

Any comments appreciated.

Mark

I'm sure there must be a version of those radio synch's clocks with a USB connection. Perhaps something like that shown on the top of this page.

www.atomicclockrugbymsf.co.uk/ntp-time-server/atomic-clock.html

Thanks for the response Dave

I was thinking that any GPS receiver receives a time signal from an atomic clock which is onboard every GPS satellite (as far as I'm aware).

If we can get cheap consumer GPS devices we should be able to get cheap accurate time.

GPS units sold specifically for the purpose of time sync seem to be at a premium. It would probably be more cost effective for me to set up wireless internet - but even then Windows Network Time Protocol appears (from what I read on the internet) not to be a full implementation and hence not so accurate. Dimension4 may very well be a full implemenation of NTP or something different - but it does appear to be respected and therefore would appear good if one has internet access to sync the PC.

I'm half tempted to buy one of these yokes to see what I can get out of it - only thing is I don't need GPS (ie lat/long) per se on my laptop.

I'm open to any experiences from others before I make a complete fool of myself.


Mark