To all,

I just wanted to give anyone curious as to the true performance of the ProMark2's navigation capability, a brief synopsis on what I was able to do today. I was sent out on a 5.4 acre tract that is about 150' E-W by 1600' N-Swith slight angle points called for along the way. I decided that since the tract was wooded and in places the fence was missing due to recent construction that that PM2 might simplify my corner search. What I did was to start at the front (road side) corner which is the SWC of the 5.4 ac. I allowed the PM2 to do a position average on the point for a minute. Then knowing that the mapping angle for the area was about 2° I applied that to all the calls in the deed. With a legal pad and an "El-Cheapo" TI-25s calculator I calculated the coordinates for the next point which was about 500' North. We hiked back to the point and the coordinates landed me within about 10' of the location. I then calculated the next point and was positioned (IN TREES) to within about 3'. I did this for all the corners I could not easily find. The worst I found was about 12'. This could easily have been due to my initial coordinates which I based all of my subsequent search coordinates on. I would think that this procedure could be even further refined if you did a static observation on a boundary point or traverse control and then searched calculatiing from the statically derived points as a coordinate basis. The error I described could easily be halfed.

While I certainly would not use this to find lot corners on a 100' by 150' lot, on rural tracts it could be the next technilogical compass. A note though, be considerate of :
1 WAAS correction (make sure you are not getting an autonomous code position)
2 Multipath
3 Coordinate basis
4 If you are looking for SP coordinates (such as control points) run Corpscon against the LAT/LONG displayed and the SPC's displayed to make sure that the system is outputting properly.

I am impressed to say the least,
Shawn Billings
SIT Texas

Shawn:

Thanks for keeping us posted on the PM2. I have been looking at the unit as an affordable way to get into GPS and all information on the capabilities of this little instrument are greatly appreciated. It looks like all surveyors can have GPS, at last.

T.Wilson - MA

Hey

Things are good here...see you soon.

Shawn

You mean you actually made it all the way from Stumpwater TX to somewhere Indiana? Did you leave a trail of breadcrumbs or stop and tag 500 way points into your extrex to find your way back?

Things are normal here. As in normal!

Dad

p.s. good thing ya'll aren't lost in Luweeziana or Oklehomer.

JD,

Did you let him calc. the points for that corner search.... Indiana.....HHHmmmm. Sounds suspicious to me but that PM2 wouldn't lead him astray would it. :o)

I've got a niece going to ND in South Bend. Loves it.

Jimbo

Naahh,

I wouldn't dare let him take a PM2 outa here. Not with his ability to meander a 700 mile drive. Or is it 900 miles?
I think he was using his brunton compass in the car to keep him on track. But, you may be onto something about those coordinates. Did NGA make a big shift we weren't aware of?

J.D.


I meant NGS not NGA....damn bifocals

Modified By J.D. Billings on 10/19/2001 at 10:47 AM

It might be possible nowdays with all the plastic in a car to actually use a brunton on the dash...
Better anchor it good though...

If Shawn get's lost in Oklahoma (kinda hard with the roads N-S and E-W..but he's welcome to come by and 'refresh' his supplies (obviously if he's lost in Oklahoma, he's been dipping into the ice chest)...

TM