I have a Bad-Elf Surveyor unit which claims accuracy ~1m when post-processed, but I am at a loss to find software that can differentially correct the raw NMEA/UBX logs that the unit will record. I checked the bad-elf site to see if they had a list of apps that could do it, but couldn't find anything.

Anyone know what will take the .UBX file and correct it?

  • I don't know if you've tried this already, but the company website says that they have updated the iOS app to output a RINEX format, which you could then use with NRCAN's PPP service. Let me know if you try it and how it works - I have one that I'm planning on trying out in the next few months.
    – Carl
    Commented Nov 18, 2016 at 23:52
  • I have noticed their new RTK abilities in the firmware upgrades lately, but don't have an RTK account. I'll give the RINEX export method a try, thanks!
    – user25644
    Commented Dec 1, 2016 at 21:15
  • You are looking for kinematic processing I guess. Right? For static processing DGPS there are plenty of online services. Commented Jan 8, 2018 at 18:16

2 Answers 2


If you can convert them to rinex format you can use the online Precise Point Positioning (PPP) service provided by the Canadian Geodetic Survey. You can find out more at http://www.nrcan.gc.ca/earth-sciences/geomatics/geodetic-reference-systems/tools-applications/10925#ppp, or google NRCAN and PPP

It's a great service, but I'm not sure if it is intended only for Canadian data. I'm sure there are other PPP services out there as well.

  • Handily, I am in Canada! However i am looking for something that will do it with a fairly simple workflow instead of having to convert file formats. Bad Elf says the data can be post-processed but are leaving that to 3rd party app developers to tackle, but as yet i have not seen any 3rd party apps take it on, which is why I brought it up here.
    – user25644
    Commented Aug 4, 2016 at 23:15
  • Converting it to RINEX and processing online is the simplest (not autamated) workflow I think. Doing the DGPS yourself requires more software and downloading the precise ephemeris and clock files. Also note that PPP is not DGPS. Commented Jan 8, 2018 at 18:15

Once you have used the raw data logger to output a RINEX file, you can use the RTKLib to post-process your data using either

  • a) DGPS, using RINEX data from a known base station (CACS in Canada or CORS in the US) or
  • b) PPP, using satellite clock and ephemeris data (.sp3 and .clk files available from NASA CDDIS and IGS).

Bad Elf has an explanation of how to correct your data with DGPS on their website here. Also see tutorials from Latitude51 (1, 2, and 3; note, however, Latitude 51 is using L1/L2 data) and Rtkexplorer. You can also find a more detailed discussion of L1-only PPP at this GPSWorld article.

However, I've been a little frustrated with the available explanation of how the ublox chips work and how to best implement the bad-elf's capabilities, so I've opened another question here; possibly someone has some additional insights that they would like to share.

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