Hi everyone,
great resource you've got going on here, glad I found it :)
Ok back to the subject, my question is this: When using RTK (Trimble VRSnow) corrections, why is my height orthometric?
I want an RTK-corrected UTM29 position.. but after feeding corrections into my 5700 I get a position + orthometric height which makes me think its using a local grid projection...
But where is it getting this from!!??? I didnt load any projection or Geoid into the receiver!
Here is an example of some of the corrected string:
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Replies
Hi Jack,
My initial thought is that the GPGGA message is defined, it has a set of rules. The rules include that the co-ordinate system is always WGS84 and the height is relative to the Geoid. your receiver will have the geoid built into it and the GPGGA string will call out the separation and apply it.
I suspect if you were to output your position information in another format, maybe a native raw position string(does that exist in trimble) that defines the height as being on the ellipsoid, you would get a different result.
Note your position is also in LL and not UTM.
I have never used a 5700 before or the associated trimble software for setting it up. I could be well off the mark.
Thanks for the reply, this gives me something to work with, I will get back if I come up with anything new
Cheers