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TDS raw file using RTK GPS

5 REPLIES 5
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Message 1 of 6
tncajun77
2481 Views, 5 Replies

TDS raw file using RTK GPS

I use a TDS Survey Pro to collect field data with an RTK GPS system. The raw data (.rw5) is converted into a fieldbook file (.fbk) for import into a survey network in Civil 3D. When it is imported, all points become CONTROL POINTS. Also, the interactive graphics are not displayed showing the base setup and the radial side shots collected by the rover. I noticed there are no options for setting up a GPS survey system under the Equipment Database tree of the survey tab. Should I assume that Civil 3D does not understand a raw data file collected by RTK GPS using TDS Survey Pro? Edited by: tncajun77 on Oct 6, 2009 8:46 PM
5 REPLIES 5
Message 2 of 6
Anonymous
in reply to: tncajun77

GPS points are stored in any given RAW file (aside from static measurements)
as simple NEZ points - all that you get are coordinates, thus they are
stored as control points in the database. This holds true for any GPS data,
not just TDS. What type of measurements should you be seeing in Civil 3D?
There are no "observations" as you would have with conventional surveying.
Aside from that, the Equipment Database is only used to apply conventional
correction factors when performing a survey adjustment - besides *maybe*
wanting to run a least squares adjustment on the entire network, there are
no adjustments that you can do to GPS data that would require the types of
correction values stored in an equipment database.

--
Jason Hickey
Autodesk, Inc.
http://beingcivil.typepad.com


"tncajun77" wrote in message news:6267087@discussion.autodesk.com...
I use a TDS Survey Pro to collect field data with an RTK GPS system. The
raw data (.rw5) is converted into a fieldbook file (.fbk) for import into a
survey network in Civil 3D. When it is imported, all points become CONTROL
POINTS. Also, the interactive graphics are not displayed showing the base
setup and the radial side shots collected by the rover. I noticed there are
no options for setting up a GPS survey system under the Equipment Database
tree of the survey tab. Should I assume that Civil 3D does not understand a
raw data file collected by RTK GPS using TDS Survey Pro?

Edited by: tncajun77 on Oct 6, 2009 8:46 PM
Message 3 of 6
Anonymous
in reply to: tncajun77

The only benefit you'll gain really from using the fbk is the ability to
create figures for structures and breaklines. As Jason posted, there's
really no "tweaking" or analysis that can be done on RTK data.

wrote in message news:6267087@discussion.autodesk.com...
I use a TDS Survey Pro to collect field data with an RTK GPS system. The
raw data (.rw5) is converted into a fieldbook file (.fbk) for import into a
survey network in Civil 3D. When it is imported, all points become CONTROL
POINTS. Also, the interactive graphics are not displayed showing the base
setup and the radial side shots collected by the rover. I noticed there are
no options for setting up a GPS survey system under the Equipment Database
tree of the survey tab. Should I assume that Civil 3D does not understand a
raw data file collected by RTK GPS using TDS Survey Pro?

Edited by: tncajun77 on Oct 6, 2009 8:46 PM
Message 4 of 6
Anonymous
in reply to: tncajun77

Trimble, using Trimble Link, converts the GPS into FBK observations.
HOWEVER, there is an error in the Civil 3d sea level correction calculation.

"All RTK vectors are converted to equivalent grid azimuth, horizontal
distance, and vertical distance observations from the RTK base station
for inclusion in the field book file. This allows the position of a base
station to be updated in the field book file so that when it is
re-imported into the AutoCAD Civil 3D or AutoCAD Civil system, all the
RTK points fixed from it are also updated. These observations have the
appropriate projection correction applied and are not sea level
corrected. All antenna measurement corrections are also applied during
this process."

Matthew Anderson, PE CFM



Jason Hickey - Autodesk wrote:
> GPS points are stored in any given RAW file (aside from static measurements)
> as simple NEZ points - all that you get are coordinates, thus they are
> stored as control points in the database. This holds true for any GPS data,
> not just TDS. What type of measurements should you be seeing in Civil 3D?
> There are no "observations" as you would have with conventional surveying.
> Aside from that, the Equipment Database is only used to apply conventional
> correction factors when performing a survey adjustment - besides *maybe*
> wanting to run a least squares adjustment on the entire network, there are
> no adjustments that you can do to GPS data that would require the types of
> correction values stored in an equipment database.
>
>
Message 5 of 6
gsmercier
in reply to: Anonymous

Jason,

I have a survey performed with our GPS that I would like to check the horizontal accuracy on.

I was thinking that a 'least squares' would be the way to go. I have something incorrect because I keep getting a 'degrees of freedom < 1' response when I ask it to run the analysis.

I read your article on BeingCivil.com 'From Grid to Ground...' regarding point file types. I'm thinking that this might be the issue. Can you shed some light on least squares analysis on gps survey data?

Sincerely,

George Mercier

P.S. I've attached our first days .raw data file incase that might help. I've added .txt to the end of course.

-George
Message 6 of 6
wfberry
in reply to: gsmercier

I hope you take this as constructive criticism.  You are continuing a more than 2 year old  thread that quite frankly has nothing to do with the previous problem, other than both are RTK, GPS.  This forum has repeatedly requested to start new threads when there are different issues.

 

Thanks,

 

Bill

 

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