PPK GCPs without Rover Rinex

I have 2 RS2 units. I am new to doing GCPs and using a RS2 as a Rover! I made what is probably a fundemental error.

I set one unit up to use as a Base (static node) and left on tripod for 2 hours.
I will use PPP (Precise Point Positioning) to get the corrected location of this base.

I set the other RS2 unit to Kinematic to use as a rover and i made up a survey file for marking the Ground Control Points.

I did not activate the logging function for the Rover!! (i dont understand why the survey mode lets me record data with no Rover logging. My previous DGPS (Trimble) did not - the survey screen only started when in Rover logging mode).

Now i have a Base rinex file and the Reachview (V2) CSV file with the average Lat/Long/elev for the times I recorded the GCP.

Can I just use the Longitude, Latidude and Elevation data together with the Collection start time and collection end time (all from CSV file).

And calculate the average Dlat, Dlon and Dhgt readings from the POS file to offset the values to the true locations?? (ie do a manual correction to the average lat, long & elev from the CSV file)
(this was my understanding on the principle of using Base data to correct Rover data from the Emlid docs)

I tried googling and searching the forum. I found an earlier thread Collecting GCPs By PPK Workflow
where RTK_Hunter did a similar thing (i think) but he had Rover rinex files as well and the data corrected by offset did not match the data obtained via the Rover rinex?

is there a recommended workflow for offsetting Rover data with a reach CSV file but a corrupt or absent Rover Rinex file?

Grateful for any advice. I assume i am not the first person to do this?

Hi Paul,

Sorry to say that, but without raw data logs from the rover, you can’t process the data. Observation files are an essential part of the PPK technology, and without them, the software can’t calculate any solution.

Logging is just one of the possible options on the receiver. Since it’s optional, it isn’t turned on by default. However, you can set automatic logging starting every time the receiver is turned on. To do that, you just need to go to the settings for a separate log and tick such an option.

And one more comment from me. To work in Stop&Go mode in Emlid Studio, you need a CSV file from ReachView 3 app. The one from Reach Panel doesn’t contain all the necessary fields. The new app also contains all the latest features and improvements, so I recommend switching to it.

Hi Julia

thanks for the bad news.

I will try the auto start as you suggested to avoid future simialr problems, but I have a few questions to try and understand how the unit behaves when in autostart mode so as to try and avoid similar missing rinex files in the future:

My current workflow for using the RS2 (as a base) has been to turn it on, check it is on Static, go to logging page, set it to do a 2 min average of current location, set the logging to on.

I originally tried to do a longer initial average, but i found if the phone’s screen saver/lock activates or i move too far away from the DGPS, then when i unlock the phone the accumulation jams (just stays at the particular level it was at when screen locked) and i have to restart.

I also found that the logging on/off switch (on screen) does not always work (transmit to RS2). I have clicked the button to on (and it shows green on screen), then i go away and do drone flight, but when i return to turn it off, it was not actually on. No data, start again. I now know to look to make sure the logging file is getting larger with time before i walk away.

Similarly when i turn the unit off, it does not always stop the logging, and i sometimes have to start a new log, which terminates/saves the previous one.

Question -

  1. if you do use the auto start, does it automatically use the previously set averaging time before it starts the reading? [I currently only see a message saying the location is updated and then the correct Lat/Long/elev on the screen after i manually apply the averaging and it goes to 100% without jamming (which is why i have been doing it manually and only for 2 min - too hot to stand and do nothing except keep phone active for longer)].

  2. If i switch to Kinetic mode after i turned it on, does it restart the logging inthe new mode, or will the unit record a mixture of both static and kinetic and be corrupt, or will it ignore the new instruction until a new log file is started? (i did this accidently last week as well as i have 2 units and the phone logged onto the one that was already setup as the base 30m away instead of the one next to me that i wanted to set as a rover).

Thanks again Paul.

Paul,

Let me answer your questions first and then add some comments about the issues you described.

The receiver’s approximate position is automatically calculated and recorded to the header for every raw data log separately. This process doesn’t use the coordinates from Averaging in the Base mode tab. So you don’t need to do it additionally before the logging.

Here is also the guide from our docs covering all the necessary steps to record the logs to do Stop & Go in Emlid Studio.

Raw data log contains GNSS observations from the receiver without calculating accurate coordinates. It’s just raw data from the satellites.

At the same time, Kinematic and Static are positioning modes. They affect the way of calculating a solution in RTK but not the observations themselves. So no matter if you set positioning mode as Kinematic or Static, the raw data log will be the same.

When your phone is far away from the Reach RS2, ReachView 3 loses connection to the receiver. As a result, you see that averaging stops in the app.

As for locking the screen, I’ve tried to reproduce it on my phone. When I did that, the timer indeed paused, so I saw the same time when I unlocked the screen. But then it aligned and kept going correctly without restarting. What ReachView 3 version do you use? What is your mobile phone model?

Hmm, it shouldn’t work this way. What firmware version is installed on your Reach RS2? Please generate the Full System report from this unit and share it with us via support@emlid.com. It’ll help us take a closer look at what is going on on the device.

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