> Hi, > > A number of recent entries to this list have mentioned topics relating to > GPS timing and environmental corrupting factors (e.g. Ionosphere, Temp., > Humidity, etc.). Personally, I am very interested in setting up a very > precise relative time between locations (maybe 100s of meters to 10s of > kilometres apart) on time scales of (maybe 100s of seconds to 10s of > minutes). I noted some members referred to dual frequency receivers for > overcoming these effects. Can anyone point me to some literature, articles > or links to overcome these environmental factors? > > Regards, > > Stephan.
I'm guessing a dual-frequency receiver is not so important in your case because your stations are geographically close enough together that many of the GPS systematic errors are common for the two sites. And since you're only concerned with relative time rather than absolute UTC this is all to your great advantage. First, please read this excellent paper: Introduction to time and frequency metrology http://www.tf.nist.gov/timefreq/general/pdf/1288.pdf It sounds like GPS common view would work for you. This has been used for a decade or two. In fact most timing labs use this technique today. So here's where to start with GPS time transfer: http://www.tf.nist.gov/timefreq/time/gps.htm Can you give us an idea of what level of accuracy you need and over what time intervals? Something like a few ns over a few hours or a day? What local frequency standard do you plan to have at each station? Here are a few good GPS time transfer papers: Time and Frequency Measurements using the Global Positioning System http://www.tf.nist.gov/timefreq/general/pdf/1424.pdf Time and Frequency Dissemination: Advances in GPS Transfer Techniques http://www.tf.nist.gov/timefreq/general/pdf/1998.pdf A Comparison of GPS Common-View Time Transfer to All-in-View http://www.tf.nist.gov/timefreq/general/pdf/2091.pdf Comparison of the One-Way and Common-View GPS Measurement Techniques using a Known Frequency Offset http://www.tf.nist.gov/timefreq/general/pdf/1827.pdf Time and frequency distribution using satellites http://www.tf.nist.gov/timefreq/general/pdf/1602.pdf /tvb _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
