Any great text books detailing
1. Error Propagation & Adjustments
2. Terrestrial control establishment field procedures and Least Squares Processing?
3. Baseline static control fundamentals and processing (TBC or infinity)
My field procedures could tighten up.
- I always collimate (check and adjustment my instrument before control establishment)
-Use high precision 1mm accuracy prisms set as low as possible over the control point.
-Two face measurements 3 rounds
Problem
Starting baseline quality and adjustment procedure I get lost.
Help would be great
Thanks
James
These are not exactly what you ask for but I recommend two things to get you started. One is the NGS/Bill Hennings document "User Guidelines For Single Base Real Time GNSS Positioning", free for the downloading. The other is Jan van Sickles book "GPS & GNSS for Land Surveyors". You need to understand the datums and projections. If you are using StarNet to do your adjusting I'd go for their software manual.
Three rounds is usually overkill, IMO. Two should be plenty. Back in the day of 1/2 minute transits and even 20 second theodolites we made 6 sightings to try refine the average angular results. Nowadays we have 1, 3, 5 second guns and, in a majority of cases, there is little to be gained trimming that down with extra sightings. You double mostly to trap blunders.
You did not mention the adjustment of your rod bubbles and the tribrach. Check those if you have not already.
Thank you - Ill definitely download/purchase the noted books and check the tribrachs and rod level.
Legend!
These are not exactly what you ask for but I recommend two things to get you started. One is the NGS/Bill Hennings document "User Guidelines For Single Base Real Time GNSS Positioning", free for the downloading. The other is Jan van Sickles book "GPS & GNSS for Land Surveyors". You need to understand the datums and projections. If you are using StarNet to do your adjusting I'd go for their software manual.
Three rounds is usually overkill, IMO. Two should be plenty. Back in the day of 1/2 minute transits and even 20 second theodolites we made 6 sightings to try refine the average angular results. Nowadays we have 1, 3, 5 second guns and, in a majority of cases, there is little to be gained trimming that down with extra sightings. You double mostly to trap blunders.
You did not mention the adjustment of your rod bubbles and the tribrach. Check those if you have not already.
Great recommendations. I will say if for everyday Land Surveying work 3 to 4 rounds are plenty. I choose an even number always. Now one thing I will say is in the last few years every project that a survey company has picked up that requires FGCD guidelines be met which is usually not the norm for everyday land surveying is just read the requirements and follow what they say. Do not try and short cut it even if you do just as precise work if you have not crossed your T’s and dotted your I’s it is all for not. If they say a minimum of 2 4 hrs of collecting static just do that.
Only top of the RTK manual by Mr. Henning. Also grab the old NGS standards and Proccedures manual. This will give you the old requirements and walk you through how many rounds to achieve Horizontal and Vertical surveys. This doesn’t mean you should follow these exactly today because I don’t believe for everyday surveying you need to turn 16 rounds with a 1/2” instrument but it will give you some perspective. Think about it this way. Angular accuracy has not changed since transits were built. One could buy a 1” 1/2” and 20” theodolite or transit many many years ago. What has improved is the EDM and the compensators in what we use today. On top of what was stated above watch some of the free NGS videos on horizontal datum’s and vertical datum’s some older ones by Dave Doyle are great. Read the ISO and din specs based on your brand of equipment so you understand how you achieve the precision quoted by the manufacturer on that specific piece of equipment.
Next thing is if you are on the Land Surveying side please do not get so wrapped up in measurements that you lose site of what’s really most important for boundary surveys. Remember and I recommend to anyone starting out or on their way to becoming licensed is to know your priority of calls. Also ask those practicing in your area not just who you work under is try and see what they are doing and what those before them were doing. This can change by locality areas all within a state. Understanding how the approached boundary resolutions in city or rural areas is paramount when you are retracing them. Understand the blunders that one might see when following someone who went a 1000 ft with a steel tape or chain or rod. What year was the survey done did they chain along the ground or pull horizontal distances. Going up and down hills from one monument to another might make you come up way short or way long to finding the original which may or may not match the math. Remember no matter how well you can measure does not mean the other surveyor was wrong. Don’t establish pin cushions.
Gain an understanding of precision vs accuracy. Remember redundancy is your friend. Your best traverse closure means little to that one bad side shot.
Any great text books detailing
1. Error Propagation & Adjustments
So this isn't going to give you practical details on Item One, but it will provide a language to think about error
https://mitpress.mit.edu/9781940380087/an-introduction-to-error-analysis/
Alibris.com has several copies of the 1997 edition of this book available for under $10. But one less that it had a few minutes ago.
(For the record- I do not recommend older editions of the book I recommended because the technology is advancing.)