Online Transformation via RTCM messages

Dear all,

When setting up a new project in ReachView 3 it would be nice to have an online transformation feature.

Just tick it and you are good to go.

It shouldn’t be too complicated since all relevant data is normally incorporated into the RTCM messages.

The difference in position (N/E) between my Stonex S10 (Cube a5) and my RS2 is only 2 to 3mm (using German SAPOS; HEPS), but when it comes to the orthometric height the gap widens to a max. of 60mm.

Having a look at the RTCM messages I found out that some values differ from the ones found in ReachView3.

If it isn’t too much work I would highly appreciate the implementation of the above mentioned feature.

Many thanks in advance.

Regards

Buddy

What message did you look into?

The RTCM messages 1021-1027 in Cube a5.

E.g. for difference in value:

Flattening of the Bessel 1841 spheroid according to SAPOS 299.15281535132334

ReachView3 299.1528128

Not sure if this is the reason for the difference in height.

Regards

The 7 parameter transformation is according to Bursa Wolf:

Delta X: -571.944
Delta Y: -68.378
Delta Z: -387.953
Delta Alpha: 0.67674
Delta Beta: 0.14908
Delta Gamma: -1.83306
Scale: -12.97594

Correction of geoid height is -2.045

Hi @buddybuxbaum,

When setting up a new project in ReachView 3 it would be nice to have an online transformation feature.

How do you see the result of this transformation and how it should be performed? Sounds unusual, so I want to check I understand your request clearly.

The difference in position (N/E) between my Stonex S10 (Cube a5) and my RS2 is only 2 to 3mm (using German SAPOS; HEPS), but when it comes to the orthometric height the gap widens to a max. of 60mm.

If you connect both receivers to the same mount point and use the same coordinate systems, I don’t think there should be such a difference. Can you compare the coordinates from Stonex and Reach with the known ones?

Also, please record an RTCM3 log on Reach when it’s connected to this mount point. Possibly, it’ll give me a hint of what’s going on.

Which vertical datum do you use in ReachView3? If you select DHHN2016 than the official geoid GCG2016 is applied. If it does not match what you are getting from SAPOS RTCM vertical corrections than it is strange. Do you have a benchmark nearby to verify?

Does the ntrip provider use antenna height or not? You should see that from the 1008-message.

Hi all,

Many thanks for your input.

Currently I’m quite busy, so that my answers will be concise. Sorry for that.

The stream contains message type 1008, correct.

I use Germany_Zone_2 + DHHN2016 height in ReachView3.

I will be off for a couple of days. After returning to office I’ll take my equipment to a benchmark and have a thorough check.

Logs can be provided thereafter.

Online transformation is normally achieved via residual gap distribution.

Many thanks.

Regards.

Buddy

Hi Buddy,

Thanks, will be curious to see the logs and new check results!

The RTCM messages 1021-1027 in Cube a5.
Online transformation is normally achieved via residual gap distribution.

I see what you are talking about now :slight_smile: We want to add 1021-1023 RTCM3 messages support to allow online transformation in future releases. There’s no ETA for now, but we plan to work on it shortly.

Hi Buddy,

Did you get a chance to check the height on a benchmark?

Hi Kseniia,

I will be out of office a little bit longer as planned.

Keep you updated.

Regards

Buddy

One thing I always check when I get to venture into the real world to survey instead of AutoCAD world is to visit a known passive control mark to verify the RTN service I use.

We have an excellent service here in SC and the operators usually inform us via email if there’s any problems with the RTN. For me, it’s a sanity check to make sure I’ve got my coordinate/projection/geoid model settings correct.

Another method if using the RTN service is to PP or submit an observation point to OPUS. It’s amazing how accurate the RTN is versus PP and OPUS.

Hi Buddy,

Thanks for keeping me posted! I wanted to check if there’s any news, just in case.