Correct height in Germany (DHHN16)

Emlid Flow & Emlid Flow 360
1

Hi everyone,

I’ve just received our new RS2 and set it up. We’re based in western Germany and I’ve got it all working fine with RTK correction, etc. but the Z coordinates are totally wrong. It seems as if DHHN16 datum is not supported. I’ve made sure to use a mount point with RTCM3 which according to my local correction data provider does provide the correct datum, so am not sure where am going wrong. Any ideas or workarounds if this is a software limitation would be welcome.

Thank you!

Markus

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2

Hello Marcus,

what you get ist the height above reference ellipsoid and not orthometric height (Normalhöhe). To geht the official german height above sealevel, you have to substract the undulation/geoidheight. The official German geoid as a dataset ist sold by BKG (Bundesamt für Kartografie und Geodäsie) and costs for the whole Germany about 800 EUR. Or you go to their websit and use the provided online tool.

Manfred

3

Hi Manfred,

thank you very much, we’re in NRW and have SAPOS subsription which includes datum over RTCM3 using ETRS89 /UTM32N (25832). We’ve got Topcon and Trimble GNSS units as well and all of them manage to work with with our SAPOS subsription and get the correct height. So I would assume that it’s a software issue rather than anything else or I’ve put in the wrong setttings somewhere, but since eastings and northings are correct and datum is provided by SAPOS as well I don’t really know what I am doing wrong.

1 Like
4

Hello Markus,

you are not doing anything wrong.
At the moment you only get ellipsoidic height with your Reach unit. And you have to substract manually the undulation to get german “Normalhoehe”.

Manfred

5

Hi Manfred,

thank you! That’s what I feared. So there’s no way to use it on site at the moment unless we go back and run every point through the tool? I’ve been playing with some of the downloadable datums as some are from just over the border in Holland and return pretty good results but obviously not the correct heights. Do you think there will be downloads provided for Germany soon? I’ve just found a different post where it said that DHNN16 apparently was already implemented in a previous version of the survey app but taken out of the new release.

Thank you,

Markus

9

Hi Markus,

We indeed removed support for this vertical datum temporarily because it requires some reworking. We are currently in contact with BKG to bring it back. Please keep the app up-to-date.

2 Likes
10

Hallo Markus,
ich antworte Dir auf deutsch, da es ja um ein lokales Problem geht.
Du kannst einmal einen Blick auf die App WebCaddy von Caddy Geomatics aus München werfen.
Die vertreiben auch die Emlid Produkte und wissen daher um was es geht. Die App gibt es aber nur für Androidgeräte. Ich nutze aber meistens ein Iphone mit meinem RS 2. Daher nehme ich nur in WGS 84 und mit ellipsoidischen Höhen auf. SAPOS Bayern bietet einen Onlinedienst an, mit dem man, ich glaube bis zu 1000 Punkte, kostenlos in UTM oder GK mit DHHN- Höhen umrechnen lassen kann. Vielleicht gibt es so etwas ja auch in NRW.
Viele Grüße
Bernhard

11

Hi Svetlana,

Thank you very much for the info. Could you say, just roughly, when to expect the update. I really don’t need an exact date but I would need to know whether it would make sense for us to wait for it or return the unit. I’ve used it today surveying on site an have been pretty impressed and would like to keep the RS2 but if we have to wait for months until the upgrade comes it doesn’t make sense for us to keep it as calculating the height manually slows down the workflow immensely.

Cheers,

Markus

1 Like
12

Hallo Bernhard,

Vielen Dank für den Tipp ich werde mir das gleich Mal ansehen,

Danke,

Markus

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Please keep it in English. Even though it is a local issue, others might learn or get inspired.

14

Hi Markus,

I wish I could provide you with an estimation. However, this depends not only on us but also on the BKG department.

I can say that German datum support is one of our priorities right now. We’ll do our best to make it as soon as possible.

7 Likes
16

Hi Svetlana,

That’s great to hear, thank you very much!

17

5 posts were split to a new topic: Same height measurements with ESRI

18

Hallo Svetlana,

to get the correct height is also a crucial criteria form me. I intend to use reach rs2 receiver for forest tasks in East Germany. For different issues it is very important. I am not so skilled to use additional Software or calculation, for me it should work as I need it. So please do your utmost to get this problem solved.

Thank you

1 Like
19

Hi Eckhard,

I’ve just seen your post and since you’re in the same position I am in, here is what I do at the moment to work around the problem until it’s solved.

You can use your survey data and copy a single point, ideally in the centre of the location you’re surveying into this calculator: Onlineberechnung von Quasigeoidhöhen mit dem GCG2016

I then take the exported CSV file and use Excel to substract the “Quasigeoidhöhe”, which you will get from the website above, from all my heights of my survey. If you use the “special paste” / “Inhalte einfügen” command you can do this easily. You copy the “Quasigeoidhöhe” and highlight all your heights in Excel, then use “Inhalte einfügen” / “special paste” and use the substract option.

I hope this helps for the moment. It obviously only works for a smallish area. If you’re surveying broader areas you will have to do multiple centres to keep the deviation at a low level.
And just to be fair, the link above was given to me by my supplier laserscanning-europe.com, when I was looking for a workaround too.

Cheers,

Markus

1 Like
20

Hallo Markus,
thank you for the information, I will do so, as long as there is no other solution.

Thanks,
Eckhard

21

Hi everyone,
any update on this topic? When can we expect DHHN support again?

Thanks in advance
Sebastian

2 Likes
23

Hi Sebastian,

Welcome to the community forum!

The support is on its way! We’re hoping to add it in the future updates of the app. However, I can’t be more specific that this as this process depends on several parties simultaneously.

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25

DHHN2016 is now back in Reach View 3. I’ve just tried it on site against Trimble and Topcon survey data and it’s within 1cm deviation, which is great news!
Thank you very much!

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26

Hi everyone,

As Markus has mentioned, the DHHN2016 heights for Germany are back! To use them, check that the ReachView 3 app is updated to the latest 5.6 version.

Please note that projects created before the system’s temporary removal will ask you to re-download the geoid file. We’ll be glad to hear your feedback!

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