I have a client that is using RTX.
I set up some control based off local CORS/OPUS and NAD83(2011).
He loaded up the DC, using his TSC5/R12i and went out and each point was a consistent 5' off (the same direction).
I said that sounds like an ITRF to NAD shift error.
RTX must be broadcasting ITRF and his DC/receiver combo is not shifting to NAD83.
Does anyone here know what he's lacking? Is this common?
We haven't ever subscribed to RTX, so I'm not familiar with the software.
> Does anyone here know what he’s lacking?
Control of the base station.
If you are not running the base station yourself, you are at mercy of what ever it has been set to.
In this case, I agree ITRF seems likely
>Is this common?
Yes, absolutely.
The usual solution is to run a site configuration against your control points
Isn't there a way to shift to NAD83 using Trimble software?
He would have to set that up in the job when he created it. Additionally, theres no"shifting" once youve started a constrained data collection process, ultimately the data is WGS84, one of two flavors.
If he's chasing your control, then just stopping and creating the new job with right reference frame will get him the best results, and quickly.
Otherwise, you can: stop, callaborate and listen:
I will be searching for a solution, I know a couple of colleagues using RTX and will be calling them to see how they handle ITRF vs NAD83 coordinates while using it. The simple solution would be to set up Global as ITRF and Local as NAD83. I'll give that a try on my own.
Either way a calibration isn't workable, the site is 200 sq. miles, the Lidar mapping is finished, the permits are filed.
"ultimately the data is WGS84, one of two flavors". Careful there! First of all there have been eight versions of WGS 84, the most current is WGS 84 (G2296) + the epoch of the day of observation. You would only have WGS 84 if you process in the "here" mode and even then you would have to scrub any observations from other constellations as they are not defined in WGS 84 and since you would then be working in the Federal Radio Navigation Plan Standard Positioning Service the uncertainty of any position could easily be in the 2-4 m range in the horizontal. I suspect as others have that somehow this person is in ITRF. MightyMoe if you processed with OPUS the datasheet gives you the ITRF14 values so that should be a simple comparison.
Yes, I processed it with OPUS, it matches my CORS calculation by 0.0001" both lat and long, which is basically .01'.
The ITRF lat, long is shifted 4.7' from NAD83. However, it's in a different direction from the client's number, I'm very confused at this point.
"However, it’s in a different direction from the client’s number, I’m very confused at this point."
Yes, that is VERY confusing indeed!
I would verify EXACTLY which datum your client is really using just to rule that out.
With time dependent transformations (like ITRF) the epoch of the coordinate realisation is important.
You may be seeing 'current epoch' values, and comparing them against something older, or possibly vice versa.
For example down here we have an NZGD2000 datum, where the published numbers are generally epoch 2000, not current.
I'm still looking into when I have time. I looked at some Trimble videos, which weren't very helpful.
It seems that I need to have RTX to make sense of it, which I don't. The client does but they are in a somewhat remote location and all their work is onsite.
Basically, they don't understand the equipment and I don't have hands on access to it.
I just finished updating all my programs and got them working so maybe today I'll be able to figure it out.
All I want to do is have RTX survey in NAD83(2011).
MightMoe,
you mentioned that the translation is not in the right direction. I wonder if the transformation in being applied when it should not be (like a double application of the transformation for some reason). ITRF>NAD83>NAD83
I wonder that also. If I input the Lt, Lg the client sent me I'm NE 7' from my NAD83 position. If I input the ITRF # it's WNW 4.7'. None of that makes sense. I need to look at the survey style of a DC with RTX enabled.
