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UBLOX Neo-6P Logging Raw Data to Pixhawk - How to convert to Rinex

Posted by Ben Harris on May 10, 2015 at 8:05pm

Hi Everyone.

I have a .log file from a UBLOX Neo-6P which is logging the Raw RXM data to the Pixhawk log file at 1hz.

The question I have now is what is the easiest way to convert this to a Rinex format? RTKLIB obviously doesn't recognize the file or the information in it.

3691204825?profile=originalI've removed all of the other messages using ultraedit and attached the file with the GRAW messages.

If anyone has any information on how to convert this that would be great.

Thanks.

gps_graw_only.txt

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Replies

  • Sulu October 6, 2016 at 6:44am

    Hi,

    I've tried without success to store raw data using an M8N (drotek) receiver but I can't output the obs file when creating GPX-KMZ.

    Is there someone who use the neo M8N and are able to output the OBS file?

    thank you,

    Marco.

  • Benjamin L July 7, 2016 at 3:17am

    Dear Michael,

    The navigation data for GPS satellites can always be downloaded from CDDIS. Instructions are available here: http://cddis.gsfc.nasa.gov/Data_and_Derived_Products/GNSS/broadcast...

    All the best,
    Ben

    Michael Tietze said:

    Hi Giang Le,

    thanks for the fast answer. I did already enable UBX in ucenter but do you log the .ubx with the pixhawk directly or do you have a companion computer? I mean logging the .ubx file directly with ucenter on the windows computer is possible but not really handy for the copter ;)

    So far I was just able to get the .obs data out of my log via MP. 

    Best greetings from Munich

    Michael

  • Michael Tietze February 29, 2016 at 12:59am

    Hi there, 

    i have a problem. I was finally able to get the Rinex data out of the log as a .obs file. I am using the arducopter 3.3 and i configured my UBLOX Gps which is able to give out raw data via Ucenter.

    Now i wanted to postprocess the data via rtklib but it always asks for .nav data. Does anyone know how and where i can get this .nav data from? Is it logged as well?

    I attached my logfiles in the google drive folder. Sorry i was not able to upload it directly.

    https://drive.google.com/open?id=0B37T0lz3DShYekJNUVlVWXNFMVk

    It would be great if someone could help me with that.

    Thank you so much and best greetings from Munich

    Michael

    • Giang Le > Michael Tietze February 29, 2016 at 1:08am

      Hi Michael,

      You have to use Ucenter to enable ubx protocol in Message table (Right Click on UBX then click to Enable).

      Then you could use RTKLIB 2.4.2 part 10/11 to extract *.ubx file to *.obs and *.nav file.

      Hope this could help you.

      p/s: from Viet Nam

      Best Regards,

      Giang Le

      • Michael Tietze > Giang Le March 4, 2016 at 6:15am

        Hi Giang Le,

        thanks for the fast answer. I did already enable UBX in ucenter but do you log the .ubx with the pixhawk directly or do you have a companion computer? I mean logging the .ubx file directly with ucenter on the windows computer is possible but not really handy for the copter ;)

        So far I was just able to get the .obs data out of my log via MP. 

        Best greetings from Munich

        Michael

      • Jhabindra khanal > Giang Le February 29, 2016 at 11:26pm

        Hello , Giang Le and every one. 

        I logged the data via u center and I got the rinex after convert raw logged. But I confused about integer ambiguity. Rinex files gives the numbers of cycles from receiver to satellites for example.123661948.306 cycle for satellite no . G2.  where is that cycles are ambiguous?? Please share the knowledge. 

  • Artem Kholodkov June 21, 2015 at 7:02am

    Hello Ben Harris, how did you configure your gps and pixhawk for storing of this data. I have Pixhawk with neo-M8N. Can you help me?

    • Ben Harris > Artem Kholodkov June 21, 2015 at 2:01pm

      Hi Artem,

      There was a new parameter created called GPS_RXM_RAW in both plane and copter which should do all of the "configuration" of the GPS to allow the logging of the raw data. Tridge did find a small problem with it though so it wasn't quite working in the 3.3.0 release. Tridge tested it with his NEO6P and I've got a 7P, and it works well on both. I'm not sure if any changes need to be made for the M8N to allow it to work, but I have some M8T's on the way as well, so I'm as interested as you are in finding out.

      3702575339?profile=original

      A couple of things to save yourself some doh moments.

      1. Ensure you have GPS 2 enabled and set to Ublox, also ensure it is outputting single point position data in MP. (if using it as your secondary GPS in serial 4/5)

      2. Make sure you have the above parameter enabled for whatever sample rate you are looking for. We're currently testing but I believe we will be able to get away with 1 hz for the time being.

      I'm not sure how far away the master version is with the fix, but I'm guessing not too far.

      Michael Oborne has also added a rinex conversion in Mission Planner, when you generate a KML+GPX from the dataflash log you will also get a 3.0 obs file.

      Hope this helps,

      Ben

      • T3
        Thorsten > Ben Harris June 23, 2015 at 12:56am

        Hi Ben and Artem,

        The M8N has no official support for raw data. However, it is possible to record data in TRK format. Unfortunately, this is not compatible with RXM-RAW.

        The problem with the M8T is that is uses the RXM-RAWX protocol to handle Multi-GNSS raw data and not GPS only as in RXM-RAW. See: https://www.u-blox.com/images/downloads/Product_Docs/u-bloxM8_Recei... (UBX-RXM-RAWX: page 246). So logging raw data of the M8T is not working with the current APM version in master. 

        I started working on a patch. However, it seems to require a higher baudrate because of a higher bandwidth needed to log all the data. ...I better leave this to the devs...

        Best regards,

        Thorsten

        PS: RTKLIB already supports RXM-RAWX.

        • Jhabindra khanal > Thorsten October 21, 2015 at 2:19am

          Hello Thorsten,

          I have EVK-M8T. How to extract the raw data only for gps.?? I found there the data with multi -GNNS . But i need RAW data for GPS .. and which converter(like rtklb,teqc....) supports for UBX-RXM-RAWX to get rinex. I need to observe carrier phase for precise positioning. please explain me in detail. my email jhabindra@jbnu.ac.kr.

          Thanks in advence

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