Does your use of the Topcon Tools demo require that you use Topcon branded receivers?
Combining total station and GPS data in least squares is where the fun begins.
You have two independent measurement systems providing a doublecheck on each other.
When combining the two in least squares I have seen total station data make it really obvious that a GPS solution was looser than the reported sigma (more often with RTK, sometimes with fast static).
Far less often, GPS data has made obvious a total station blunder (wrong backsight, forgot zero, bad HI etc.)
LGO will do this. Topcon Tools will do it too. No idea about Trimble.
We use Star*Net. If we had a budget & were gonna start fresh we'd jump straight to Columbus.
Any kind of least squares that can combine the observations will give you complete overkill. I like overkill. It helps me sleep at night. You will begin to see error ellipses everywhere instead of points.
The difference is calcs, star*net reduces 3D to 2D, does the calcs on grid, and fluffs it back up to 3D, whereas Columbus and LGO and move3 and perhaps others all keep it in 3D geodetic which is theoretically better, and may actually BE better on a job with big elevation changes. I got all this from Loyal, who tells me star*net is fine for our little lot jobs.
EDIT: sorry, off on a tangent, Loyal was talking about combining GPS vectors from different post-processors in least squares. Still, combining independent methods is good, as is overkill.
Most of the pay-for-RTK networks have the actual base station data sitting on an FTP server for free. This is the beautiful side effect of the real time networks. People are willing to pay for real time positioning, base station data is the free sawdust.
Also, CORS data is free to download, you probably have fairly dense CORS where you are.
Nope, it'll eat anything. Has the same IGS antenna database as OPUS, too.
I'm in western MA. The density of CORS stations is not great. Nearest stations are typically a minimum of 20 miles away.
Al, are you currently utilizing your L1 receivers to connect to any RTN servers, such as those commonly run by state DOT's? I think you will like your results if you could connect to one using a dual frequency receiver. In fact, you should find out if you could connect to one that offers GLONASS support as well.
If you are ever curious about LSA you can download a demo LSA program to play around with. Usually they are fully functional, they just have a limit on the number of points, usually like 20, that you can adjust (which might not be so bad when you are just learning). We use Star*Net, and Microsurvey has a demo on their website.
Star*NET users
Looks like MicroSurvey is starting to add the features users are requesting to Star*Net. They released V7 earlier this month that included level loop closure checking and direct OPUS solution importing. This was enough to convince us to purchase the yearly maintenance agreement so we could upgrade, and the price wasn't too bad. You guys might want to check out the release notes on the MicroSurvey website.
Loyal is right. We mix Leica and Ashtech receivers. I just open the raw data files from our Leica receivers in Leica Geo Office, and export the data to Rinex, and they import fine into Solutions. Everything should work fine with the Rinex file format. In fact, if it were up to me and I was designing a GPS receiver, I would just make my raw data format Rinex... I would also complain loudly and frequently if I found modern post processing software that wasn't importing or exporting Rinex correctly.
> ...LGO will do this. Topcon Tools will do it too. No idea about Trimble...
Yes Trimble will do this. We used TGO for a long time but we recently upgraded to TBC when we purchased an S8 and TSC3 with Access. I am still learning with TBC but, back to the original question, both TGO and TBC will allow you to process GPS, total station and digital level data together.
David
Quick question about TBC.
Does TBC apply the Helmert Corrections (based on the NAVD88 Gravity Model) to the raw leveling data?
Thanks,
Loyal
With One Dual Frequency Receivers....
You can submit to OPUS and you do not need an L2 key to solve against your PM3s.
If you want to download and solve against CORS yourself in Solutions, then you need the key.
With two Dual Frequency Receivers you can get very good solutions in Solutions without a key. I have tested L1/L2 data with and without my L2 key and sometimes the L1 only solution is marginally better, i.e. the third decimal place. I have little time to really care about the diference.
However there are times that even with only 1 L2 receiver you are going to want to solve everything against the nearest or your favorite CORS. In the past for me that was always NJIT, but now NJIT has covered the state of New Jersey with CORS, plus I now have PennDOT CORS with 20 miles North and South of most of my work. My default now is under 2 hours OPUS-RS positions. I just submitted 6 for some weekend work because NJWC (Warren County) was slow getting files to NGS, in fact most of the New Jersey CORS were slow at the beginning of the week. I suspect an NJIT server problem.
Your priorities should be:
1/ get an Ashtech L1/L2 receiver, no need to complicate life with additional software.
2/ When you are convinced you've done the right thing, get the L2 key.
3/ Then get a second L1/L2 receiver.
Remember you can do RTK with ProMark 3s.
Paul in PA
David
Not sure Loyal. I am still going through tutorials with TBC.
David
It could be hard to tell!
There are basically only two ways TBC could do it:
1. Ask for (require) a gravity value for exery TBM/BM either in the input file or when setting up the routine.
2. Ask for (require) a Latitude/Longitude value for exery TBM/BM either in the input file or when setting up the routine. This option would REQUIRE a file containing the NAVD88 Gravity Model for your area somewhere in the TBC database.
Loyal
