It wouldn't allow me to reply below. Our first test project with PM2. Using three HARN monuments for control within 5km of the project site. holding one fixed the worst miclosure was .05' vert. .03 horiz. Compared four sided traverse EDM vs. PM2, about 600' legs, Worst diff. was .03', 3 out of 4-- .01'. Impressive.
Modified By Norm Miller on 11/27/2001 at 7:18 PM

Gee, Norm, I'm sorry your HARN isn't better. ;>}

Did some more testing vertically on the same project site. 3 wired in BM's at all four corners of the project and compared differences between them with Promark 2 values as follows:
BM 1-2= .01'
BM 2-3= .01'
BM 3-4= .00'
BM 4-1= .02'
Modified By Norm Miller, LS on 11/29/2001 at 11:22 PM

Norm:

Thanks for letting us "would be", or "going to be" PM2 owners know how well this system works.

Tell Ashtech to put you on the payroll.

T.Wilson - MA

Thomas
It might interest you to know the observations were performmed by first time users under my watchful eye. Advise spending the extra $$ for fixed hieght tripods for consistant antenna hieghts.

Norm:

Funny you mention that as I have been considering that problem. I have decided that while fixed height tripods are a good idea they are also very expensive at $700 each. I know that it is "recommended" procedure to use them but I figure that if I am careful a tripod will work just as well. Adding 35% to the cost of the system isn't in my budget, maybe later after I purchase the third reciever.

I do appreciate your comments. It is really nice to see what the PM2 can do before I lay my $$ down.

T.Wilson - MA
Modified By Thomas Wilson on 11/30/2001 at 2:57 PM

Thomas,
I suggest you might want to look at a websight such as hayesinstrument.com and check out the prices on the Seco 2m pole and tripod (a bipod with three legs). The setup we use is way less than half of the amount you mentioned.

You also might want to consider the advantages of being able to measure three vectors (3 receivers) at a time vs. one (2 receivers). The network above was done in 5 1 hr sessions with 3 PM2s. 2 PM2s would have taken at least 10 sessions minimum. It doesnt take long to make up for that extra $1500 or so.

I am located in the state of Indiana and work for Indiana State Parks and Reservoirs where we are considering acquiring either Trimble Pathfinder XR's or something from Ashtec only recently heard of. We desire sub-meter accuracy and need to get our roads, trails, buildings and utilities collected and input as simply as possible in to ESRI products (ARC GIS). We don't have many (if any) who have ever used this equipment before and would like suggestions what you all out there might recommend. We don't have a lot of money to pay others to collect this for us, but if available to be hired, our state parks are a pretty nice place to visit! Please comment back to mmontgo749@home.com with ideas about the two product lines mentioned or others you may care to discuss. Thanks!

Norm:

I see you buy a GPS fixed height pole and a bi-pod. I didn't think of that. The GPS tripods with the long legs run about $700, as I mentioned before. Maybe I'll try your idea.

I know that three is better than two with the recivers but cost is a consideration to start. I can always add the third unit latter.

Thanks

T.Wilson - MA

I agree that fixed height is a good idea. I don't really like 2 meter poles, as they are a bit high for us vertically challenged people, but it is nice to not worry about the height. A good friend and GPS user of mine bought the $700 fixed height tripods and he likes them, but I have got great results from the 2 meter poles and the Seco tripods.

The fixed height poles do not fix the problem of going back to pick up a reciever one's assistant had put over a point and finding it plumb...but not on the punch mark on the cap we were tying in. Got a nice centimeter fix on the edge of that cap........

The 2 meter pole mentioned above has pins to set it at 2.0, 1.8, 1.4 or just clamped anywhere in between. Naturally you add the fixed height from top of tripod to antenna. So vertically challenged should not be a problem.

Trust me. For large control projects, fixed height tripods pay for themselves in a few jobs. Also, the pole rotates so you can verify the level bubble adjustment or adjust it easily in the field if out.