Base correction from NTRIP - HELP!

[andrewpaulrickard (Andrew Rickard)]

Hello!

I am new to the EMLID community and would like some assitance in PPKing a base station point with NTRIP corrections. I am unable to obtain FIX results from the static processing.

I have uploaded the base station data, along with the Observation and Navigation files for the processing:

MapatekBase_20240624091341.zip

If somone could look at them to see what I am doing wrong I would greatly appreciate it.

Cheers!

[TB_RTK]

Data from the refrence station doenst not cover the periode for your rover.
Rover is from 9 to 10, and refrence data is from 11 to 13 ish

[andrewpaulrickard (Andrew Rickard)]

Hi TB_RTK,

Thanks for checking it out. However, it was my understanding that the logs from my EMLID use local time (Spain), while the logs from the NTRIP reference station use UTC +2. The logic I was using is as follows:

The Emlid receiver time log is 9:13am -10:58.
The NTRIP Service LOGS 11:00 - 12:00 and 12:00 - 13:00.

I also downloaded NTRIP corrections (Descarga de ficheros RINEX - Instituto Geográfico Nacional) for 9:00 - 1000 and 10 - 11:00, but I still end up with a floating value.

You can download these rinex files here: WeTransfer - Send Large Files & Share Photos Online - Up to 2GB Free

Thanks again!

P.S Checked out you website. Very cool!

Andrew

[TB_RTK]

There is still difference in time.
If you open files and look at the header. See attached image

[andrewpaulrickard (Andrew Rickard)]

Hi TB,

My understanding is that the NTRIP correction is in UTC + 2, so the time stamps will not match.

Hence the 10:00 data log from the Emlid Receiver will correspond to the 12:00 data received from the NTRIP Correction. Is this wrong?

Andrew

[TB_RTK]

I downloaded the previous 2 hours and Fix is then possible.
Raw files have no offset, they work of GPS time
Link to solution with fix and two files for the reference station
https://drive.google.com/drive/folders/13vl3wZpeyg6072MxMOYm4a3H5zH6RRFZ?usp=sharing

[timd1971]

@andrewpaulrickard

Double check your Height of your MapatekBase too.

1.58 or 1.8 M?

[andrewpaulrickard (Andrew Rickard)]

Thanks again TB!

However, my solution using your data still does not give a fix solution.

I have also downloaded the corresponding GPS Time 9:00 - 10:00 + 11:00 - 12:00 from the NTRIP service and I still only get a float solution.

I’ve attached a brief video of the steps I hve taken to process the data. Perhaps I am still missing something :-/.

Emlid Studio 1.8 2024-07-08 09-33-04.zip (3.0 MB)

[TB_RTK]

When i face float only or poor Fix I always start with the GPS system only and enable more system as I need.
With your data I started with GPS ONLY and combined forward/backward with 100% Fixed solution. Try this first and enable more systems if you like.

[andrewpaulrickard (Andrew Rickard)]

Hi TB,

Success!

Thank you very much for your assistance.

Cheers,

Andrew

[merryna.anggriani]

First thing to check when doing a PPK, aside from the log data quality, is to ensure that the observation log from the base covers the rover’s observation time. Time conversion might be confusing sometimes. You can check the log or ES to see both data logs in GPS time (GPST).

For processing, I’d like to start with the default settings and change the filter type to Combined. Also, as @TB_RTK suggested, it is a nice trick to begin with GPS only and then add more systems.