Paul
you would be surprised how close your GPS will check to your total station, under 0.01' is common (assuming you compare apples to apples, you either convert your TS to grid or your GPS to ground but the software will handle that for you).
I think my ProMark3s with GNSS Solutions processing are better than my much more expensive Topcon Hipers that I use in my regular job.
But a lot of the time you aren't measuring the line once with GPS and once with TS. A lot of the time you are using GPS to measure lines you can't measure with TS.
In that amount of time were you able to tie into a control system that you could translate the position into other systems if needed?
Most of the time I don't have the advantage of wide open sky and on occasion I need to locate monuments that are on the other end of "dynamic forest" or "bois de arc thickets" that would take a day minimum to brush and measure 1200ft with a TS.
> In that amount of time were you able to tie into a control system that you could translate the position into other systems if needed?
It was a local situation that involved 4 monuments and two lines. There was no need to translate into any system.
I do not make boundary determinations in the field any more. I used to balance/adjust a traverse and then set monuments. As I get older I would rather make another trip back to the site and then set final monuments after doing calc's in a better setting than the field.
GPS is not always useful. My current project is traversing around the NW quarter of Section 7, T17N, R15W, MDM (this Section is the subject of an appellate decision-People vs Thompson). There's a big open area near the center of section but that's about it. I can use that to tie my survey to CCS83 but that's about it. There isn't much hope of using GPS to strengthen my traverse. After the traverse is done we'll go back and mark the lines for timber harvest.
paul
Very happy with my Sokkia GSR 1700 CSX
Jan Van Sickle in gps for Land surveyors said L1 is good as L1/L2
up to 10 miles rtk and static more or less as far as you would like to go
say 80 km i will look up the correct pages and post would not like to mis quote
Jan V S but have no time to look up the correct page right now
Will do make a simple test for you paul set up two of my three L1 in
tribrachs and get a simple ground distance at 400 meters in i would guess
about 15 minutes is all the L1 1700,s would need using one L1 as held as base
then process in static software
pull the 1700's out of the tribrach and measure the same distance with the
geodimeter 650 robot 1sec 1mm and post the distances
The Geo 650 on calibrated Concrete piers was always with in +- 1mm to 800
meters over 5 piers so have little reason to question it as the correct "true"
distance ground distance
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Paul I think for the most part we would use TS for the work, but dont you have a lot of jobs that interlink that you could use the L1 GPS to combine things? What about that one monument 3000+ feet away you cannot see without several hops?
The bosswifegoddess and I discuss this often. We are just slow to make the move on this stuff.
Bryan I have three ProMark3s sitting here doing nothing that I would love to see put to work even on a rental basis. The processing software is free for download from the internet. I have poles to put them on or you can use tripods and tribrachs.
Security is a little bit of an issue if you don't have three people to watch them. I've kind of held my breath and left them at times, so far none have been stolen. Of course the one you are watching is fairly safe.
Dave thanks for that offer. I would not feel comfortable leaving a third one to sit anywhere unless it was secured if I am using someone else's equipment.
I think that may work for us. If we were to do this how easy is it for you to mail those out?
Um...Paul..
May I ask why you are looking for that kind of accuracy?
paul
> Will do make a simple test for you paul set up two of my three L1 in
> tribrachs and get a simple ground distance at 400 meters in i would guess
> about 15 minutes is all the L1 1700,s would need using one L1 as held as base
> then process in static software
>
>
> pull the 1700's out of the tribrach and measure the same distance with the
> geodimeter 650 robot 1sec 1mm and post the distances
Thanks Peter. I am looking forward to the posted results.
Bryan
> Paul I think for the most part we would use TS for the work, but dont you have a lot of jobs that interlink that you could use the L1 GPS to combine things? What about that one monument 3000+ feet away you cannot see without several hops?
Gee Bryan..I am racking my brain to try and remember when I shot a distance over 2200 feet, and that was last weekend on a drizzly day and basically flat ground.
LA County has so much control in the ground I think it has lowered the basin a few inches.
There are times that GPS would speed things up, but I have this way of thinking about sharing the fee of the survey with those that help me, so if it takes me an extra 8 hours to do a job..I am OK with that and the guys get some extra cash.
Joe
> May I ask why you are looking for that kind of accuracy?
The +/- 0.2' in 1200? Just curious is all.
< 20 minutes for +/-0.015 ft.
Typically if I am working with a company that has GPS equipment, I'll take it out each day. I can mix and match as needed for the task at hand, and have jobs I do solely RTK, as well as ones solely robotic.
In urban settings I use neither, but always get someone from the company to serve as either rodman or iman, depending whom I'm working for that day. I've found as a general rule it is not good time management with robotics nor a wise move leaving any tripod mounted equipment unattended.
Paul
I bought a fancy RTK setup several years ago because I thought I would left in the dustbin of surveying if I didn't. I really had to force myself to use it instead of TS and at least half the time when I did use it I could have gotten the same data in way less time. Now that my fried receivers requiring an $8K repair on an outdated system are sitting in the garage, if there's a job that really demands GPS (once or twice a year) a friend helps me out for a day or two with his. Don't get me wrong, it's a great thing and if I had it, I'd use it but like you, paying the guys to take a little longer to get the job done is OK with me compared to the cost and headache for the kind of work I do.
Steven
> Now that my fried receivers requiring an $8K repair ..
I am all ears! How did they get fried Steven??
They are in 3 soft bags about 12" square (roughly). I could get them to you somehow and you could try it out. You probably would need some help initially. There's an antenna that goes on the pole or tribrach and a separate receiver that has a clamp for a tripod or pole. The receiver also is the controller (has a screen and keyboard). The batteries aren't brand new obviously but so far I haven't had one run all the way dead during the work day. Entering in codes is a little clunky because you do cell phone text style (push the 1 four times for C, etc). I keep separate paper field notes which makes processing later easier.
Bryan
I guess you must not have the difficulties I face in the different hillsides of the Bay Area tying in old deed lines that are monumented. Sometimes I need to spend a lot of hours traversing and even then it has to be an open traverse in order to get things tied down. It is not possible to take a shot 2200 feet to that monument in those cases.
Cool Dave perhaps I will take you up on that.
Steve
You have mentioned this "fried" set of RTK receivers before, but I don't recall any details (brand/color, problem, cause). I may have missed it though (I do that a lot).
My RTK gear is (at least) 10 years old, and still works like a champ!
Loyal
< 20 minutes for +/-0.015 ft.
Between the typically heavy tree canopy typical to South Alabama and multi story buildings, many times within a 50 foot right of way, what I see gives very limited sky view.
I have found a noticeable advantage having GLONASS capable receivers in the above captioned circumstance. I am able to survey in areas with the 2700ISX that I could not previously with the 2700IS series.
