OPUS variation
I just looked at the CORS positions and there are only 4 now scattered across the islands. Most of the CORS are out of commission. There is only one on the big island, one on Maui, and two near Honolulu.
I'm guessing it's a way more challenging environment than what the CONUS crowd is used to. You might try resubmitting after a few days.
Good idea. Yeah, we're pretty sparse. I give it another try in a few.
Looking at the distances from my base:
each had one at 163.26 miles and 37.57 miles
Then one has one at 71.85 miles and the other, 2302.2 (!) That's friggin' northern CA
And the discrepancy seems to only be in the OPUS. The RTK shots had some that were close to duplicate from pre battery swap to post and they are very close H&V
Thanks.
Do you have TBC to roll your own, the CORS on Mauna Kea isn't very far away, the one on Haleakala should also work well, after that it's getting out there for control.
If you can single process to those two and they match, I would consider that a win.
Great idea. I don't have TBC yet - it's actually something I'm saving for and have been watching tutorials and such to help prepare for the day I can get it installed. Kinda pathetic 🙂
This is a very true statement. I have gone through the process to check the stations themselves against each other often. Especially when I am above to do a very large static network. I have found a few antennas that were replaced and had not had the time to be updated at the OPUS level.
You can download a 30 day free trial of TBC. If you are in a pickle. I have done this before just to help a friend. Or use opus projects instead of the generic OPUS so you can get more data and solve the network solution to check for outliers etc.
lol on 10 being bad. I remember planning and seeing 4 to 5 after planning sessions. We have become spoiled with multi constellations for sure. I remember the first time I had a r12 put in my hands and I could see 32 satellites and it was using over 20 of them. I started laughing and the guy I was with said what’s so funny. I said well I see 30 plus satellites. The gps constellation itself is only close to that number which you would never see that many gps ones at a single moment. Now with all the other constellations if less than 20 we start worrying. Man how things have changed.
Looking at the distances from my base:
each had one at 163.26 miles and 37.57 miles
Then one has one at 71.85 miles and the other, 2302.2 (!) That’s friggin’ northern CA
I thought you might be looking at some long distances. Working back from the spec sheet of the unit a rough calculation (easing math by assuming all error was in the GPS unit) of the ppm error I had you at least 100 miles from the CORS stations. If that is the closest CORS, you might be seeing the best results you will get out of OPUS processing.
Given the distances you posted, I would probably download the data from the CORS and process each 3 hour dataset with the 37.57 mile and the 71.85 (still a pretty good ways away) mile station and see how they worked. If the answers weren't good, I would do a single baseline from the 37.57 mile CORS for each 3 hour dataset and compare them to each other.
The R8-3 brought Galileo tracking but you mentioned only GPS (US) and glonsss.
And static observations do not give an absolute elevation determination without long observations. So even in the US you can log a file for 4 hours in the morning and 4 hours in the afternoon and they can return elevations 0.1 feet difference. NGS guidelines would be I think something like 3 separate 4 hour observations reach 12 hours apart , or a 12 hour observation. I’m probably off a bit. But you get the idea that you’ll have variability with individual 3 hour static files.
OPUS isn't the tool for dave-o's enviroment. I would hold the island's one CORS point on Mauna Kea and compare the resulting value to a tie from the CORS on Haleakala. Once you have a good number (if that's possible) I would show enough site control to recreate it on site and also show the CORS values used with the date of the survey.
Where dave-o is ground is moving fast, moving probably up and moving westerly.
Local site control is critical.
