I'm using a ProMark 700 Network Rover. It has a small arrow (triangle) on the top and bottom of the receiver. Also has a notch on the outside edge lining up with the arrows. Are these arrows supposed to be orientated to north while taking observations?
I also noticed that if I rotate the receiver 180 it sometimes reads up to .05 different. I checked the plumb bubble on my pole and it is in adjustment.
Hijack
Now I know why I've heard it mispronounced: oar-in-tayshun
Just having a bit of fun. Sorry. Cain't hep meself.
> I also noticed that if I rotate the receiver 180 it sometimes reads up to .05 different. I checked the plumb bubble on my pole and it is in adjustment.
I'm not familiar with that specific make and model, but if you don't rotate it 180° what is the difference? My point is that 0.05' between any two RTK occupations may be within the normal range, depending on other conditions.
My old ones have a N with an arrow so you point it north. Those were sold in pairs so you point the base N arrow north or you may prefer south, just be sure you are pointing the rover unit north arrow the same direction and the offset for each cancels out. Not sure how it works with a network rover. But to be safest, point the north arrow north.
Hijack
That dang I before E thing always gets me:-)
With A Network Rover You Still Point North
Even if you do not have an equal antenna to balance offsets against you want to have the same antenna position for all rover points. What one wants in network surveying is to have the best relative precision between all project points.
Paul in PA
With A Network Rover You Still Point North
yes, exactly, I don't see how pointing it north will work form what I know, it was meant to cancel each other, now all the antennas I no longer have the old north pointing arrows. I figure you can't hurt yourself pointing it north.
If You Do Not Have A North Arrow...
...the standard is to have the cable connection South.
I have some antennas that did not come with North arrows and since others often set them up a Permanent marker easily solved the problem.
Paul in PA
From www.ngs.noaa.gov/ANTCAL:
SPP89823_10 NONE ProMark 700, P/N 89823-10 Arrow/disp ->N NGS ( 3) 12/09/18
4.9 -1.6 60.0
So the X offset from the center of the pole to the L1 electrical center of antenna is 4.9 mm, the y offset is -1.6 mm.
These offsets are used when you post-process data collected from the antenna. However, they are not used in RTK calculations.
However, if you rotate the antenna 180 degrees, then the electrical center of the antenna moves twice the offset. So the total distance is 0.0103 meters or 0.034 feet. Which is nearly 5 hundredths, right?
Mark
Good explanation Mark. I had been to a site and established a control point. I came back a few days later and decided to check the point before I started collecting data for the day. I noticed I was 0.05' off. Just for grins I started rotating the pole. I was dead on after rotating 180.
Guess it would be good procedure to always orient the receiver north from now on. Each day is a learning process.
Are you sure your pole isn't bent?
I am going to make a statement that will get me into hot water:
"Every new pole that I sell has at least 3 mm of runout. Every single pole. Some are much worse."
I measure runout by holding the point in a jig, then rotating the pole while held mid pole. The run out is the eccentricity from min to max measured at the top of the pole.
Evidently it is not possible to build a straight pole. And as you might expect, they do not get better with use.
So, the answer is "Yes, your pole is bent."
M
Mark, you should invent and market the least squares self correcting antenna pole!
Poles would be somewhat better if they were not jointed (solid one piece).
If you took a shot and then rotated 180 and took another shot, and both were done carefully, the average would probably be an improvement. OK so the LS pole would auto rotate and take a shot every 60 degrees or so and then process the result (lots of redundancy on a planned scheme). By the time you do all that, might as well set up a tripod with a good plummet and do the 180 (rotate the tribrach between shots).
I can go with that, what's a little slop between friends?
> I am going to make a statement that will get me into hot water:
>
> "Every new pole that I sell has at least 3 mm of runout. Every single pole. Some are much worse."
I certainly don't find that to be true of my SECO poles. The centering errors are simple to test just by sighting the tip of the rod and the target above it. With a target height of about 5 - 6 ft. centering errors (using an 8-minute vial) are typically sub-millimeter.
What you describe might be true for those folks who used bipods instead of tripods, though.