When I was first getting into GNSS, I purchased some old Trimble equipment, and a license of TBC. I did some in house post-processing at the time. But, when I sold the Trimble equipment and bought Topcon equipment, I decided to sell my license of TBC. I think I'd now have to buy a special module in Carlson to post-process in house. I've been using NGS OPUS ever since. Generally, it is consistent and reliable, excepting moments like the present.
@not-my-real-name Yes, I'm in Mass. I've occasionally used MassCORS for RTK work (without base) but generally I work with my own base and rover. I've never used MassCORS for post processing but will look into that when I have a chance. I've now had success using the Canadian system, although it took me a while to figure out how to convert the output values to state plane and orthometric using NGS NCAT and GEOID18.
Can you download CORS data from any site other than that of the NGS user friendly CORS?
The reason I ask is because I, too, am using the iGAGE static receivers and have CGO post processing software, but with the NGS down, getting CORS data is also gone the way of OPUS.
Alan
@alan-cook No idea. Leave in 10 hours for 3 weeks of motorcycling around Nepal, so don't really care. Just hoping there no flight delays with air traffic controllers not getting paid and they have this all sorted out when I get back.
Just because I'm paranoid, doesn't mean they aren't out to get me.
whatever happened to post process your own data? I had a client who only knows OPUS for their drone flights base station, they sent me their CHC data file, I downloaded three CORS, processed in TBC, adjusted. Total time=15 minutes.
Is this becoming a lost art?
Their file was 74 mb, would not load into centerpoint (maybe too big?).
You are so correct. Processing data ones self is getting lost for sure. On small projects I don’t worry to much but medium sized and larger jobs I prefer to do my own static and integrate that with my rtk and conventional work myself. One it aids in the relative accuracy report sometimes here where without the longer baselines to aid in the ppm scale I might fail by say .02’ or .015’. Use everything and it makes the report look good. It’s a numbers game at that point and the final resulting coords are not changing enough for me to worry.
Always great to see Mark Silver. I first bought the CHC-X90-OPUS antenna from iGage.
Now I have two iG5 antennas and can collect static GNSS data.
You have a good memory.
Historic boundaries and conservation efforts.
There isn't a way to roll your own?
I never even used OPUS for anything other than some checks.
I looked at CORS and it's down for info, fortunately even CORS wasn't a thing in the early days.
We always started with HARN and did all the static work using it, so didn't need a government interactive service.
You will need to adjust to using your own points to make it work without something like RTX. We've got points on the parking lot at the office or even an old antenna that's mounted on the roof in a pinch.
@big-al If you're using the Canadian NRCAN CSRS-PPP online system, don't you need to run the results through NGS's HTDP before using NCAT? CSRS-PPP outputs results in either NAD 83(CSRS) or ITRF20, neither of which is supported by NCAT, and I'm not aware of any tool for transforming NAD 83(CSRS) coordinates to NAD 83(2011) epoch 2010.0 coordinates — which is what I assume you want. You can use HTDP to transform ITRF20 coordinates to NAD 83(2011) epoch 2010.0 coordinates, and then use NCAT to convert to state plane coordinates.
Can you download CORS data from any site other than that of the NGS user friendly CORS?
The reason I ask is because I, too, am using the iGAGE static receivers and have CGO post processing software, but with the NGS down, getting CORS data is also gone the way of OPUS.
Alan
Only OPUS is down. You should still be able to download the rinex data from NGS CORS unless a glitch has happened and well that has happened before. I downloaded some since OPUS went down and had no problem. One station I did have to wait as its data had not come in yet but next day it was there. NGS doesn’t own all those stations in its network so if a station is shown you can see who owns it and contact them to get the rinex data just remember what a NRTK operator has and it’s also in NGS CORS it may not have the NGS published values they are usually close but not exact. So download the data sheet if that’s a requirement and adjust it when it comes in if needed.
@bill-c Thank you for that, Bill. I will review.
I went to the CORS site, it won't download recent data. Is there some secret to getting data from a CORS site?
@mightymoe Not really. I always check the availability before attempting to download. Maybe a server glitch and no one is there now to reset it so maybe it is down. While passive marks are expensive to maintain and set. Maybe not as difficult out west because urban sprawl is not as bad as it is on the east. I still wish more counties would have some good stable marks put in in safe areas for this very reason. But it’s the world we live in now. I hope NGS sees this and can some how make the raw data available from CORS during these shutdowns. I don’t worry so much about OPUS because I don’t mind solving my own baselines. But if the data is not available then we now instant relying on government have to rely on a company or manufacturer that may or may not be tied to the NSRS. One reason I have been testing both for several years now as I know what the deltas are and can live with that and have a control file I update for my work areas based on NGS published values so I sorta know what the answer is supposed to be.
I went to the CORS site, it won't download recent data. Is there some secret to getting data from a CORS site?
I just did a quick check on a station near me I use and it has data available for today up till a certain time and all days the past couple weeks. When I went to download it gave didn’t give me any issues at all. Now this one is one that is owned by NGS and not just in the CORS program. So if some you use are from other providers that could be the issue. I know smartnet has been doing a lot of work here lately so some of what they have in the NGS CORS NCN are not available for data but that his been the case even before the government shutdown. The new way to see everything is sorta clunky and takes time to get use to. It was way easier in my opinion the old way to go get the data. Now you go to the page type in the 4 digit name and you come to a page about it then have to jump to the download page which is sorta not fun. But more information about the station is in one spot.
I wrote a program to look at my receiver times, get the daily summary of CORS data files, and then provide a list of available CORS with distance and azimuth to each (I have a slider that limits the distance, I usually use 100 km). I pick some to download, and it then creates a batch file for download, here is what the batch file looks like...
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/brdc2740.25n.gz
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/igr23863.sp3.gz
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/ohmn/ohmn2740.25o.gz
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/ohmn/ohmn2740.25S
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/pamm/pamm2740.25o.gz
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/pamm/pamm2740.25S
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/gust/gust2740.25o.gz
curl -O http://noaa-cors-pds.s3.amazonaws.com/rinex/2025/274/gust/gust2740.25S
The first line is the broadcast ephemeris, second line is the precise rapid, then there are two lines for each CORS that I want, the first is the actual data, the second is the summary file (.25s) for each. I then have another batch file that unpacks those and decimates the data files to 15s or 30s.
Saves a lot of time.
WOW !
I went to CORS, no data is available from any CORS within 200km. I didn't look past that. The most recent data on any CORS point is 2025-09-30
I went to CORS, no data is available from any CORS within 200km. I didn't look past that. The most recent data on the CORS is 2025-09-30
what location/day are you looking for?
If it's necessary to collect static to position a control point, and a service such as RTX isn't in the tool bag, it's probably best at this time to set a receiver collecting data on a local known point. I assume most surveyors using GPS will have many control points available to do this.
As for us it will be RTX only for now.
Try 45N, 107W, anything within 100km and anything after 9-5-2025. It's not for work we are doing, we don't need or use OPUS or CORS much. It's more of an academic question.