Localization > System > WGS84 to NAD83 checkbox?

[tstrickland]

I haven't noticed this checkbox before, and it's not shown in the SurvCE manual.
I hate to sound dumb, but what does this do? Does it handle the shift from ITRF to NAD83? I'm guessing that it doesn't make much difference for RTK when localizing to state plane, but I'm guessing.
Should the box be checked, or does it matter?
I work almost exclusively in state plane coordinates.
thanks,
terry

[Artanian]

This checkbox does not apply if you are Localizing and adding points into the "Points" tab.

The WGS84 to Nad83 checkbox is only used if you are a Topcon Rover with internet corrections from a Topcon Ref network Base --- when you check the box it shifts the Topcon Base signal over so you can check in to Nad83 monuments with your Rover if you are NOT going to localize to any points.

[tstrickland]

Would the check box not take care of the itrf>nad83 shift if you was using an autonomous single receiver with waas dgps capability? I have in the past created shifted projections to take care of this. It probably wouldn't make much difference with a 3 meter accuracy receiver, but with a sub meter autonomous receiver it could. Does this make sense? Would it work?
thanks,
terry

[Artanian]

The best answer to this Question is to check your results while your setup live. If you are an Autonomous Rover or a Rover only with DGPS corrections like WAAS then checking this box will shift your Grid North, Grid East and Elevation by about 4 feet horizontally and vertically.

Again - this is Designed for a GPS Rover receiving corrections from a Topcon Topnet Base Ref Network. It was not designed for Autonomous or DGPS situtations.


Since it really depends on your Equipment and your Project the only answer to this is to take your DGPS Rover and check into a Published monument without the new Checkbox checked. If you hit the monument within tolerance when you stake it out then you should NOT use the checkbox.

If you miss the Published Monument by 3 or 4 feet then Check the WGS84 to Nad83 checkbox and stake it out again.

[tstrickland]

Thanks, Artanian,
I tried the checkbox on a demo version of Carlson SurvCE on my ipaq with a bluetooth holux gpslim gps receiver (on a string around my neck). I sometimes use this for rough recon. With the checkbox on, I hit a previous surveyed point initially sub foot, worse case was 4' east, so it appears the checkbox does properly take care of the shift from waas (itrf) to nad83. Not that it really matters much, since the data isn't survey grade, but closer.
thanks again,
terry
By the way, I am using hiper lites with survce on an allegro for surveying. I am leaving the check box off here, don't know if it could affect the data or not, but not taking any chances.

[cheinly]

terry

from what i have seen so far and i have not done a lot of playing with it yet.

it seems to be doing the same as the trans ; no-trans in Topcon software

it seems to get me closer in recon with the waas enabled recieviers as you stated also .

i guess if you are using a RTN or VBS base with cell phone it better be checked to see which is giving the best results.

CO

[mdriver]

I am using a Hiper + with a Trimble subscription network. I inadvertantly had this boxed checked and was seeing some major variation. I am new to using my Hiper + as RTK as I primarily was using it as static for OPUS-RS. Once I unchecked this box my checks to known NAD83 monuments were hitting great. It's a must to use this check box carefully for sure. My problem was in that my projecton list for my zone (TN) was applying the projection and the check box was throwing it out of proportion. I am comfortable with RTK and will begn using it but still have alot to learn regarding its capabilities. I am fortunate the Knoxville area has multiple monuments to check to.
Mark Driver
Knoxville, TN