Not able to achieve fixed timestamps when georeferencing images in Emlid Studio using M2 and RS2+

Reach Module / M+ / M2 RTK / PPK configuration
1

Hello,

we have some questions regarding the georeferencing of drone pictures with timestamps of M2 and RINEX data of RS2 in Emlid Studio. The latest firmware was used.

The drone uses Emlid M2 + Emlid antenna as GNSS receiver and the RS2 was logging as base station during the flight (where can we see which coordinate system and height model was used during base station logging?). The antenna height of the M2 in the Emlid Flow app was set to 0m.

M2
Is the M2 always recording satellite data in WGS84 ? Where is this written in the log files?
Do we have to set the Antenna height of the M2 in Emlid studio? If so which is the correct height?We found 0.035m in the forum as antanna default height. Our offset from the mounting point of the GNSS antenna to the camera will be put into the photogrammetry software later on.

Base station RS2 / RS3
The next questions is about the georeferencing in Emlid studio at the step of Processing the base section. We uploaded the RINEX file for the base. When using “RINEX header
Position” we get a 8 meter difference in height compared to the measured point above which the base station was positioned. When using “Rinex header Position” we get FIX position after the Process. When using manual base station coordinate input, only float position is shown. We double checked the coordinates of the base station coordinates and they are correct. The coordinate system for measuring the GCPs are Slovenia 1996 / Slovene National Grid + SVS2010.

How does Emild Studio get the base station coordinates when using the RINEX header Position?

Why do we only get fix positions when using RINEX header Position and not when using the actual base station
coordinates? Shouldn’t the RINEX header position be less accurate than our measured base station coordinates?

Thanks in advance!

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If you just use the M2/RS2 without any base, it is in WGS84/ITRF20.

Yes, but if you use an NTRIP service or a known point as your base, it will be in that origin reference of those.

Yes, highly recommended.

You’ll have to look that up on the antenna specs. You will need to ARP to L1+L2 APC distance

From the Rinex header, which is basically the last epoch of the logging, done in Single mode. Never rely on this.

My guess will be that you are inputting a Geoid height (height over sealevel), but Emlid Studio expecting an Elipsoid height (WGS84/GRS80)

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Hi @pilot_epo,

Welcome to our Community Forum!

I see that @wizprod has already answered most of your questions, but I just wanted to add a couple of extra points.

Regarding the antenna height, yes, it’s definitely a good idea to include it. One of my colleagues shared a helpful post here explaining how to measure the antenna height for the M2.

we get a 8 meter difference in height compared to the measured point above which the base station was positioned.

As for the 8-meter height difference you mentioned, I’d like to take a closer look at what’s going on. You can share here or send directly to our email address support@emlid.com.

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Okay thank you. I have send the data to to the email adress.

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