GPS Test
Posted By gary kuroski on 12/14/2001 at 11:17 AM

I want to do some observations with Z-Surveyors for control points. I currently do not have any post processing software. Is it possible to download the data from the Z-Surveyors and send it off to OPUS for corrections?
Just Curious. I have the Download programs for the receivers. I'm wanting to do an experiment this weekend and just wanted to make sure I could send them the data. Any help would be appreciated.
Modified By gary kuroski on 12/14/2001 at 11:17 AM

Re: GPS Test
Posted By jerry wahl on 12/14/2001 at 11:27 AM

OPUS will certainly process them, if you can get the data into RINEX format. NGS has some kind of receiver to rinex conversion software on their site linked at the bottom of this page:

OPUS FAQ with link to rinex conv.


Re: GPS Test
Posted By Mike Margolis on 12/14/2001 at 8:37 PM

You can download Ashtech's Rinex converter for free from out ftp site, it'll convert our native Ashtech files to Rinex, which you can send off to Opus.

ftp://ftp.ashtech.com/software/Rinex2%20v1.90/


Re: GPS Test
Posted By Bob LeMoine on 12/16/2001 at 1:56 AM

NGS's OPUS Data Processing utility is a "Point" Positioning service. It is not a true batch-processing GPS reduction software. It's meant for a validation check for GPS processing done with Vendor supplied GPS-post processing S/w.

Granted OPUS will provide an output text print-out of the Baseline lengths to three of the CORS stations used in their solution, but they do not provide actual baselines that can be input in a Least Squares Adjustment package.

If your Static GPS survey represents a "Network", the OPUS results are point positions, the actual distances between your "Network" points and OPUS's point positions may not truely represent whats on the ground.

With OPUS processing, your actual getting swing ties from 3 Remote CORS sites. If your GPS points are inter-visible, I'd recommend measuring between these GPS stations with your Total Station and compare to the GPS inverses. You may see some considerable discrepencies.

OPUS is a great tool, but be careful to use the tool correctly.

Gary's post begs the question:
If you have GPS receivers, how come you don't have GPS Post-processing S/w.
This like having a Car, with out any wheels.


Re: GPS Test
Posted By Robert Bills on 12/16/2001 at 10:45 AM

Bob LeMoine: I can't speak for Gary, but I see an awful lot of RTK only packages being offered for sale these days...One way to cut the bottom line and training costs, eh...Makes you wonder, though, where the real savings are if you don't get pp software...

OR maybe these guys are really good, and are using Ray Hintz's Hector the Vector or StarNetGPS, manually inputting dxdydz...
Modified By Robert Bills on 12/16/2001 at 10:47 AM

Re: GPS Test
Posted By Bob LeMoine on 12/16/2001 at 10:29 PM

Bob Bills: I've seen the same tactic.
Some GPS Manufactures & their Dealers don't offer Post-processing S/w, they try to convince their Customers that they don't need PP S/w - it's an all RTK World.

I have a tendency to believe the reason they promote this concept is because they don't have any decent PP S/w to offer their Customers.

Ashtech delivers PP Software with all our systems, gotta have wheels to go with that new car...


Re: GPS Test
Posted By gary kuroski on 12/17/2001 at 9:26 AM

I purchased this equipment as a RTK package only at my previous employer. We had no need for post processing software. I know that I need to purchase it to do survey "grade" work and to have the least sqaures adjustment feature. I am not trying to use this experiment for any type of accurate survey. Only as a means for training future employees.