Hello,
I have GPS for Land Surveyors, 4th Edition. I was wondering how much was added to the 5th addition. I am most interested in the process for establishing project control with Network RTK. I don't really care about scanning and UAS.
Thanks,
Dan
Enough was added to change the title of the book to GPS and GNSS for Land Surveyors. Quite a lot about new constellations, new signals, and new datums. I recommend the book highly but there isn't really much in either edition about establishing project control.
Here are some notes I made 12 years ago about establishing control for road topo jobs. Also, look into Landon Blake's "Redefined Horizons Learning Channel" on youtube.
If there’s an opportunity to buy these books, get them.
For those who don’t have such an opportunity, I’m attaching links to both books (download them), I’ll delete the books in a week.
After reading a post on the forum, I caught myself thinking that I haven’t read GPS literature in a long time, it’s very interesting how reference stations form a VRS (Virtual Reference Station).
I’ll need to read GPS and GNSS for Land Surveyors, Fifth Edition, maybe I’ll find something interesting there.
Google Disk:
https://drive.google.com/drive/folders/1LhfYOWium1xYhpYMVtwWv93gNlyRDhSW?usp=sharing
@land_odse Oh man you are awesome. I've been eyeballing this book for a while but I kept waiting to find a few books I was interested in getting before pulling the trigger on the basket.
@bstrand Anytime! 😊 In my personal digital library, I have around 70-80 books on geodesy and photogrammetry, including nearly all editions of Photogrammetric Engineering and Remote Sensing (PE&RS). I’m an ASPRS subscriber. Unfortunately, some books are practically impossible to get in digital format, especially newer ones from ASPRS—they’re, to put it mildly, not cheap.
@land_odse Great! Thanks for sharing.
@norman-oklahoma on page 243 in the 5th edition, Jan states a 30 km baseline may require a 50-minute static observation. In the past we've always used 4-6 hours on everything. I believe 6-hour observations are overkill. I believe 4-hours came from OPUS shared requirements.
With full GNSS receivers I think the static observation time can be reduced. I am looking for a table or guide on how to determine what is appropriate.
Is there a table or guideline I missed that shows where the 30 km for 50 minutes static observations came from.
Thanks,
Dan
Is there a table or guideline ...
I mentioned 4 hr OPUS sessions in that RTK Control Guidelines document. That is still the recommendation from the NGS for OPUS, because the measurement quality improves with time for about 4 hours, then the improvement with continued time starts to level off. Remembering that the baselines with OPUS are frequently a hundred kilometers or more. If you set your base to record while you are doing other RTK work these times can be achieved readily, with no extra effort.
6 hours is definitely overkill for a 30km baseline. You might well get a good resolution with 6 minutes. It used to be that we were lucky to get 5 or 6 satellites and a PDOP of 4 or 5. Nowadays 12-20 with PDOP under 2 is more the norm. Rules of thumb that worked in the GPS only days are no longer valid in the GNSS world.
@bigd1320 Interesting article I read a few years back concerning time on point -
https://isprs-archives.copernicus.org/articles/XLVI-4-W6-2021/213/2021/
I haven't tested the author's results or looked too deeply into the methods but it does seem to be a 'real world' testing of time versus precision.