Re: [time-nuts] high (spacial) precision GPS in Kickstarter
AFAIK 'normal' RTK does not provide a clock solution. There's something called 4D RTK which does: http://saegnss1.curtin.edu.au/Publications/2010/Feng2010Four.pdf apparently the results can be very good - but I think the errors quoted are for time-transfer between two RTK receivers (?). If there are papers comparing time-transfer with dual-frequency PPP to this 4D RTK I'd be interested.. AW On Sat, Jan 25, 2014 at 4:10 AM, John C. Westmoreland, P.E. j...@westmorelandengineering.com wrote: Hello Daniel, Appears that is precision for position - not necessarily time. I think NIST had a write-up on something very similar. Regards, John Westmoreland On Fri, Jan 24, 2014 at 5:40 PM, Daniel Mendes dmend...@gmail.com wrote: http://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver Has anyone seen this? Any time-nuts utility? Daniel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] high (spacial) precision GPS in Kickstarter
On 25/01/14 11:42, Anders Wallin wrote: AFAIK 'normal' RTK does not provide a clock solution. There's something called 4D RTK which does: http://saegnss1.curtin.edu.au/Publications/2010/Feng2010Four.pdf apparently the results can be very good - but I think the errors quoted are for time-transfer between two RTK receivers (?). If there are papers comparing time-transfer with dual-frequency PPP to this 4D RTK I'd be interested.. I think you need to differentiate between common-view time-transfer and the precision you get from the system itself. RTK uses the carrier phase corrections achieved from known position to kind of high-speed delta signals as received in it's neighbourhood. This affects both the position and time shifts of the receiver. If the RTK base also has a good timebase and is maintained in a good way time-wise, then both position and time gets good corrections. It's about the same type of errors as you get in the difference between common-view time-transfer comparisons. If you only do L1 C/A RTK, then naturally you will benefit from the RTK as you have no double frequency observations of your own. If you have double-frequency receiver, RTK assist to work on the tropospheric corrections and sat orbit and time errors for which a pure double frequency receiver isn't able to crack on it's own. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] high (spacial) precision GPS in Kickstarter
I know the Swift Nav guys and they are working on adding various forms of customizable timing inputs and outputs to the Piksi. It's also an open-source project, so it's pretty flexible in that regard. Henry On Sat, Jan 25, 2014 at 4:56 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 25/01/14 11:42, Anders Wallin wrote: AFAIK 'normal' RTK does not provide a clock solution. There's something called 4D RTK which does: http://saegnss1.curtin.edu.au/Publications/2010/Feng2010Four.pdf apparently the results can be very good - but I think the errors quoted are for time-transfer between two RTK receivers (?). If there are papers comparing time-transfer with dual-frequency PPP to this 4D RTK I'd be interested.. I think you need to differentiate between common-view time-transfer and the precision you get from the system itself. RTK uses the carrier phase corrections achieved from known position to kind of high-speed delta signals as received in it's neighbourhood. This affects both the position and time shifts of the receiver. If the RTK base also has a good timebase and is maintained in a good way time-wise, then both position and time gets good corrections. It's about the same type of errors as you get in the difference between common-view time-transfer comparisons. If you only do L1 C/A RTK, then naturally you will benefit from the RTK as you have no double frequency observations of your own. If you have double-frequency receiver, RTK assist to work on the tropospheric corrections and sat orbit and time errors for which a pure double frequency receiver isn't able to crack on it's own. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] high (spacial) precision GPS in Kickstarter
On 25/01/14 22:32, Henry Hallam wrote: I know the Swift Nav guys and they are working on adding various forms of customizable timing inputs and outputs to the Piksi. It's also an open-source project, so it's pretty flexible in that regard. When I looked at it, it was obviously missing. The FPGA code isn't open, but it's the only thing they keep. What the FPGA code does is also a bit unclear. A friend mentioned it to me, and just the other day said they had some form of issues. Hope it works out. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] high (spacial) precision GPS in Kickstarter
http://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver Has anyone seen this? Any time-nuts utility? Daniel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] high (spacial) precision GPS in Kickstarter
Hello Daniel, Appears that is precision for position - not necessarily time. I think NIST had a write-up on something very similar. Regards, John Westmoreland On Fri, Jan 24, 2014 at 5:40 PM, Daniel Mendes dmend...@gmail.com wrote: http://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver Has anyone seen this? Any time-nuts utility? Daniel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
