Hi
I’m having trouble getting a fix solution for a baseline that is about 35km long. I have an RS2+ and RS3. Are these receivers capable of getting a fixed solution over this distance - and what is the minimum time I should occupy the points for?
many thanks
Damian
Regardless of the receiver it depends on what you are trying to do & achieve. If it’s RTK, then 35km is pushing it for anything. Even if you get a “fix”, the atmospheric effects alone at 1ppm over that distance are going to add an extra 3.5cm uncertainty to the positions on top of all the other uncertainties.
First rule is get the base as close as you possibly can, it eliminates a lot of issues and improves the results.
Yep, I agree with @Wombo . Short baselines are your friends. Longer baselines=longer observation times. Another issue is with multipath, if you have any kind of obstructions and are trying to obtain a fix at that distance, good luck. Even if you do obtain a fix, I’d be awfully wary of the quality. I’ve posted this before and it’s from another manufacturer, it’s good procedures to follow along with methodology. We’ve got several Javad units as well as two Emlids. This applies to all manufacturers of receivers
thanks for the replies
I am trying to coordinate a single point using the static mode of processing. The Emlid receiver does not move for 4 or 5 hours. I put rinex data from the known point into the Base (CORS station), I put the unkown point rinex into the Static receiver and use the known point nav file for Navigation. I run it and it only ever offers a float solution. Interestingly if I put the same files into Kinematic processing it comes back with 57% fixed. I’m wondering why the Static mode of processing never returns a fixed solution. The base line length is about 35km. I appreciate short baselines are better, however I don’t have that option.
many thanks
Could you send me the data? I’ll look at it and share my insights afterward. I need the RINEX observation and navigation files from the base and the rover (Static base).
You can send it to me via PM or email at support@emlid.com. Thanks!
Hi Ruth - I think the data is a bit big to email - what is PM?
You can upload it to a cloud service like Google Drive or Dropbox and send me the link.
PM means personal message option in the forum.
If you are only trying to coordinate one point a better option would be to use one of the free positioning services like OPUS, NRCAN or AUSPOS depending on where you are.
Easier and far more accurate, but a little longer observation
One receiver, 8 hours or more RINEX, upload it and shortly after receive back a cm accurate coordinate.
In the settings you can configure the RS2+/3 to save the RINEX tweaked to suit the service.
Depending on where you are you may have to manually transform it to whatever coordinate system you’re using.
