Or do pictures like on page 58 of the new "xyHt" showing a GPS unit set up in the woods bother you as well? I know some people claim that with their procedures (which never are the same from person to person) they can assure themselves that they are getting good data. I personally would simply not have confidence that the data being spit out by the black box is truly meeting required accuracy standards.
Redundant check(s) with different constellation(s) would be needed to have any confidence.
I agree with both of you. Although the performance under canopy has improved dramatically over the last ten years, to portray GPS under canopy in an ad is misleading at best.
However, fully independent redundant observations will definitely give you a result you can believe - I don't think it's statistically possible to get the same wrong answer twice. By fully independent I don't mean "dump" the receiver and reshoot it ten seconds after the first shot was taken; I mean different time of day, setup, satellites, etc.
I had a Trimble R8III tracking 15 SV's while sitting upside down on my desk in my top floor office yesterday... dumping the rod doesn't do anything with these modern receivers.
I was told the same thing regarding getting the same bad answer with two independent methods. You hit the nail on the head. ..
We had a crew running grade with RTK. A second crew occupied the points from a different setup under different constellation. They were hitting hundredths. I knew better, but was dismissed. Turned out they were staking the points and hitting 'store' as the cut drifted by zero. The float was around .7 feet... To this day you can feel it when you drive that stretch of highway...
I was in the woods doing a rough planning topo with a newer unit a little while back. I was very impressed at getting lock in such thick canopy: it was a forest with large timber! The accuracy requirements were low, so I am comfortable with the data obtained. Boundary surveying, I would still use the total station, need to cut the line anyway.
spoiler alert!!
😀
I haven't got my copy yet. Maybe today.
I couldn't agree more! In the article, the Kid is doing a precise traverse to the same stone, and if there was enough room, the other checks done behind the scenes would be explained. Since the article isn't about about appropriate GPS measurement procedures - very little space was used to describe it, and therefore the old man could be construed as being iffy on his measurements.
ww co pls
- Have a nice day! Or, may your monument prevail over some guy's touchscreen.
When it comes to advertising, they usually show the item in an ordinary real situation and tell the best qualities.
Advertising - show the product, make someone remember the product every time they encounter key aspects from the ad and dream of using and having the item and eventually buy the item and keep on buying the item.
It is best plant a seed and to leave all the rest to the imagination of the reader.
Now back to real surveying with GPS.
I've used my Promark3s with success in hardwood canopy following key guidelines.
The antenna must be at a place that gets good signals. Adjusting the elevation of the antenna helps, like raising it up as high as possible. It is surprising what another 8ft of rod height will do to improve signals.
It is also practically impossible to move thru a forest with a 16ft to 20ft rover. It has to be assembled for each occupation.
Still, there is some canopy that nothing will work under, evergreen and dense green.
Knowing how to interpret the readings of PDOP, antenna signal strength and accumulate range will improve your operation under canopy.
A major factor is redundancy, like having two bases sitting on control points within 5mi of your rover and using good vector geometry between bases and rovers to add to the geometry of the constellation.
All that means a lot of units being placed in use at the same time for things to work.
It stretches the concept of having one man with a base and a rover or simply operating with a rover in a network into the need for more equipment and more manpower.
I remember a few months nearly 15yrs ago that the government turned off their scramble (or it malfunctioned) on GPS signals and I was able to get within a foot of position with my handheld Garmin GPSIII while staking straight lines thru mixed forest. We would brush it out first and then run with a TS and stake with Tpost. Then one day, POOF, it went away.
When they can pass that threshold and be able to constantly maintain a good signal under canopy, the dream may become real.
0.02
Ha. I think my favorite is a Leica ad from several years ago showing someone checking anchor bolts with RTK...
Canopy? What canopy? 😉
Just got back from the mailbox and was able to look at the picture.
IL have been able to get good results in similar environments with static and two different occupations with 12ft HI for half hour or more and with two units on control points less than 5mi away.
My biggest concern was the quote "The stone is 19.67 feet off"
I could agree that saying the measurements were 19.67 feet off, just not anything about the stone being off.
I'd suspect that the two beep one time setup could be that far off.
😉
NOT an ad
My mistake starting the ad comments... I read the first post in the thread and just assumed it was an ad without seeing it.
I use GPS in the woods for stuff that normally doesn't need high accuracy like silt fence, wetlands flags, etc.
> Or do pictures like on page 58 of the new "xyHt" showing a GPS unit set up in the woods bother you as well? I know some people claim that with their procedures (which never are the same from person to person) they can assure themselves that they are getting good data.
I see 35-40% SUNLIGHT!
5 years ago, I'd agree.
But with today's equipment, I can get that shot with confidence. (because I'll triple check it)
Don't let the ignorance of a technician negate the possible abilities of technology.
There are quite a few things that I won't let some people do, but when I've got the DC in my own hands - where I can watch the numbers and verify for myself - I may push the envelope.
> Don't let the ignorance of a technician negate the possible abilities of technology.
Folks, if proper training is not provided, you get comments like those from management. Technical minds are very good at accomplishing technical tasks. They are your billable hours guys, so keep their skills sharp through real training, it will increase your bottom line and reduce staff turnover.
I completely agree. My point was we better look at what is happening rather than what's supposed to happen. It was a hard lesson for him...
On one hand:
I have yet to understand how a firm can justify $50,000+ on GPS/Robotic/whatever gizmo, and NOT be able to justify an additional $5,000 for training.
On the other:
Most dealer-supplied training is lackluster at best, but the powers that be that won't pony up for training don't know that.
> On one hand:
>
> I have yet to understand how a firm can justify $50,000+ on GPS/Robotic/whatever gizmo, and NOT be able to justify an additional $5,000 for training.
>
> On the other:
>
> Most dealer-supplied training is lackluster at best, but the powers that be that won't pony up for training don't know that.
Dealer training can be a good investment, they have some good tips. However, to be effective, I think that each company is better served in the long run by developing its own training program, including comprehension questionnaires, training records. Having this level of commitment sends a clear and professional message to everyone.
Except that the people tapped to develop the training program rarely, if ever, use the equipment in a production environment.
