Emlid

Creating known point by EmlidReach


(Israa Kadhim) #1

Hi there,

I am trying to establish known point in Penryn, UK by EmlidReach. I was trying to process my data with AUSPOS and RTKLIB, but both of them have not shown me any result. I do not really know what’s the wrong in my data. This is my first time using EmlidReach, ReachView, and RTKLIB, so please would you explain in details what I suppose to do in order to process data. I would be very grateful if anyone could assist, or inform me if I did anything wrong according to the brief description, below.

This is brief details about what I have done in the field: This is just a pilot experiment, I used EmlidReach RS+ to establish one Ground Control Point. I set a tripod and rover (I have Not used base receiver; only rover was used) at unknown points, I checked that Data type is set to RINEX2.11. The point was measured more than 2 hours. Then, in the office, I transferred the data from ReachView app to my laptop. I received 7 files for the same point. After checking that file names are not contain spaces and Antenna type is LEIAX1203+GNSS None, I submitted them to AUSPOS. However, the data has not been processed, it is written that (AUSPOS has experienced an unexpected error, and has been unable to process your data).

Then, I used RTKLIB to post process data, I followed the instruction in EmlidReach Document (I set the mood to static; chose rover .obs fileRINEX file; output: I put rover .Inav file, lastly, I press “Execute” in the main window; and I waited until done label appeared). However, I have Not seen something similar in my output folder, the file with __event is Not contain the geographic coordinate of the measured point, not the accuracy, as shown in the attachment. Output

BTW:

  • I want to establish base station in order to measure other points by rover depending to the known point (RTK method)
    *The measurements took a place in 14/11/2018 from 10 am to 12:45 (2 hours and 45 min), I am trying to process the data from 20th November and I am still trying to find out the problem.
    *I will definitely repeat the measurements when I know the issue in the current one.

Million thanks in advance,


(Christian Grüner) #2

Can you post a few screenshots from RTK post, and also provide your ubx file ?


(Israa Kadhim) #3


(Christian Grüner) #4

You need a base, otherwise you will have 2.5 meter accuracy. You can use a CORS station for this.
Can you post screenshots of your settings as well ?


(Israa Kadhim) #5

Many thanks Christian for your quick reply, I am trying to upload UBX file, but it is written that new users can not upload attachments.

Do you mean that I need to use base receiver instead of rover receiver?
Please find attached my settings

Thank you so much,
Israa


(Timmyd) #6

You can upload your UBX file to Google drive and post Google drive link here for Christian.


(Christian Grüner) #7

Yep!


(Myozone) #8

Hello, remember you also have Lizard (liar) and Camborne (camo) OS base stations not not far from you. Incidentally, I’m <10Km from Penryn.

Dave.
Rinex data from camo and liar can be obtained from ftp://ordnancesurvey.co.uk/gps/rinex/2018/


(Israa Kadhim) #9

Thanks :slight_smile: please find the Google drive link below
https://drive.google.com/drive/my-drive


(Israa Kadhim) #10

Thanks Myozone, but my data (the one point that I measured by rover receiver) is not processed with AUSPOS nor with RTKLIB, I do not know whether I did something wrong or not.


(Myozone) #11

Your link to your UBX files didn’t work because it’s a link to Google drive in general rather than a shared link to your UBX files. Also I’m not sure if AUSPOS will process single frequency L1 data alone, looking at the AUSPOS website it mentions dual frequency, I could be wrong of course, having never used it.


(Israa Kadhim) #12

I think the link works now :blush:

https://drive.google.com/file/d/13k3I6QuETpgkFjbUwlvzkrDn874ghg63/view?usp=sharing


(Myozone) #13

Hi Israa, Your UBX file does process(I used camo reference station data located at Camborne) but it appears to have a lot cycle slips(red vertical dashes) which may indicate you were in a poor location?, also your file is dated 16/11/18 rather than the 14th. Was the rover moving ?.
Dave.


(Christian Grüner) #14

Yeah, it seems the base was moving until around 10:14 ?

@myozone
https://www.ordnancesurvey.co.uk/gps/os-net-rinex-data/health/station/CAMO this service isn’t free, correct ? O at least I can’t found the download for the obs files?


(Myozone) #15

@wizprod
From here ftp://ordnancesurvey.co.uk/gps/rinex/2018/320/ and it’s free :grinning:


(Ryszard Pażus (GeoDigitalGNSS)) #16

And I also checked. OS is a free service, GNSS Solutions is free for L1 which is completely sufficient. I’m giving the report. It is a preliminary alignment because you have to combine hourly files, add a third reference station and choose a frame of reference. :slight_smile:
Regards
PS. Ordnance Survey has developed a detailed web page, but they forgot about the Active Geodetic Network map :slight_smile:
Report_of_adjustment_preliminary_ik281.pdf (442.0 KB)


(Myozone) #18

I forgot to add the RTKplot output


(Timmyd) #19

Ryszard, They took GNSS Solutions down from being free back in Aug 2018. You have to get someone to send you the setup file because it can not be downloaded from anywhere now.

At least that is what I found about 2-3 weeks ago.


(Timmyd) #20

this is what I got in EZsurv

Observed Satellites Carrier Phase Data.pdf (81.8 KB)
PostProcessedCoordinates.pdf (65.2 KB)


(Andrew Yushkevich) #21

Hi @ik281,

PPP method with single Reach device will not give the result you need for using it in the future as a known point.
At the moment you have the following situation:

As you can see, points cloud is not really tight.

If you don’t have the second Reach, the best workflow will be the one, @wizprod and @myozone proposed.
You need to download RINEX file of your nearest station and use it as a base to post-process.

You can see the result in @myozone post: