PPK processing without a base

Is it possible to apply PPK corrections’ to the rover logs without the having the base logs? I spent the day on site, plotted 13 GCPs only to find the base didn’t log anything, when i got home. The rover unit worked fine and i have the logs from that.

What kind of rover logs ? Is this locating the GCP’s ? If you’ve got enough time per station like 5 minutes minimum, you could possibly PP against a CORS if the baseline lengths aren’t great. Also, if you can get access to local RTN stations, you could PP with them as they are spaced closer than NGS CORS.

If you don’t have enough time per station, you’ll have to visit the field again to relocate. I would also consider investing in an RTN subscription.

This is the exact reason I’ve always recommended a minimum of 15 minutes per station for static location of GCP’s. If you have a professional PP software, you would have a quality position computed. It’s always good to make sure your base receiver is actually logging data.


Hi Yes this was for plotting GCP’s, the rover logs are in the .UBX from that i have .sbs, .obs and .nav files. The local CORS station was only 4km away and i have 10 minutes on each point. Could i pricese point the CORS station and if so how?


Good ! You should be able to PP in RTKLIB. I’m not very familiar with the software as I use commercial PP software. Someone here on the forum should be able to help you use the software as it’s not that hard to learn, just a lot of settings. In the future make sure you have the base logging data. Also, 15 minutes logging for GCP’s pretty much guarantees good accuracy if there are no obstructions at each station and your baselines are fairly short.

You can also read the docs for the software and download here, it’s free ! It’s a very good software for single baseline processing.


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Thanks. Ill put a shout out to see if I can get some pointers for creating a PP.


Read the docs and download the software. It’s not that hard. The docs have an excellent explanation of processing methodology.


Agree on that, try it, it’s pretty straight forward, and you have the community here to help along the way.


Thank you but for some reason i have had the post requesting help put on hold by community flags

Hi there,

Thanks for the discussion!

It’s a good idea to use raw data logs from the nearest CORS station. There should be no issues in processing them with logs from the rover to get precise coordinates for the project.

We also provide a step-by-step guide that can follow you through all steps of post-processing in RTKLib. You can use default settings, so the process would be easier.

However, we’ve recently released a beta version of the Emlid Studio. This is our own software for post-processing. This app has all processing steps in one place and allows to post-process the data with minimum effort. The whole process is described in this guide from our docs. We’d be glad to receive feedback from you!

If something isn’t clear enough in our guides, please let me know.

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HI. Thank you for getting back to me. The step by step guide is not very clear at all. could you please explain what you mean by raw data logs from the CORS station? How can i do this in Emlid studio?

The raw data logs are what the CORS observed during operation, no different than your base or rover. Usually there is a website for downloading the files for the specific CORS you are PP with in your observations time frame.

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Hi @sgeyeuk,

Could you please clarify at which step of the guide you face difficulties? It’ll allow me to provide you with more detailed recommendations.

As Bryan said, raw data logs from the CORS are the same as logs that you’ve recorded by yourself. However, they are recorded on one of the continuously operating reference stations. To get them, you need to contact the CORS provider. Necessary logs can usually be downloaded from the website or received by email.

Please note that the CORS provider may take a fee.

After receiving raw data logs from the CORS, it’s possible to upload them in Emlid Studio and process with a .csv file of your project and logs you’ve recorded. As a result, you can get centimeter-accurate coordinates for points in the project with a Fix solution. This guide from our docs can help you with such a workflow.

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