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GPS & North

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(@geezer)
Posts: 218
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Topic starter
 

I am using a Promark 500, getting correctors from ODOT for RTK in the RTH ORGN OCRS an Zone.
(From that, it should be no shock that I don't know what I am doing).

Regardless of that, my question is this, "How concerned should I be to have the antenna pointed to the North?

thanx,
Geezer

 
Posted : July 5, 2015 5:52 am
(@holy-cow)
Posts: 25297
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Oh, no. Another North question. Haven't you learned by now that "North" exists in the same world as Santa Claus, Tinkerbelle and the Tooth Fairy?

BTW, I have no idea as to how to answer your question.

 
Posted : July 5, 2015 6:29 am
(@brad-ott)
Posts: 6185
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I think it is mostly a matter of consistently cancelling out tribrach levelling and centering type errors. North is merely a convienent direction to choose to try to consistently orient some random mark on your receiver.

You will get better answers from others. Please stay tuned. Words are hard.

 
Posted : July 5, 2015 7:35 am
(@thebionicman)
Posts: 4439
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Many antenna have a horizontal offset. It is modeled out when you orient it north. The offset is generally so trivial it doesn't matter. You can review the offset values on the nhs website.

 
Posted : July 5, 2015 9:11 am
(@a-harris)
Posts: 8761
 

I have PM3s and point the cable mount north.
It is not absolutely necessary to do that.
By doing so, it is easy to identify and orient to direction in pictures.
Old habits...

 
Posted : July 5, 2015 9:38 am
(@nate-the-surveyor)
Posts: 10522
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Bradd Ott above is right.

 
Posted : July 5, 2015 10:38 am
(@christ-lambrecht)
Posts: 1394
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I guess Bradd refers to this thread

Chr.

 
Posted : July 5, 2015 10:51 am
(@tyler-parsons)
Posts: 554
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A Harris, post: 325875, member: 81 wrote: I have PM3s and point the cable mount north.
It is not absolutely necessary to do that.
By doing so, it is easy to identify and orient to direction in pictures.
Old habits...

I just put an "N" label on the underside of the antenna where the north (^) arrow is.

 
Posted : July 5, 2015 11:04 am
(@stacy-carroll)
Posts: 922
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The Promark 2s that I started my GPS experience with had a North mark on the antenna so that all of the receivers would be pointed North canceling out a slight horizontal offset. Now that I think of it, my first dual frequency receiver's antenna had one two. I always try to figure out what "breaks" any new equipment (it's results, anyway) and defied authority (like in my teenage years) and pointed one North, one South, one East and one West just for giggles. i then ran through them with a total station and couldn't tell a bit of difference than when they were all facing North...... So maybe I was misinformed about the reason for the North mark... I don't know, but it felt gooood to defy authority again!

 
Posted : July 6, 2015 3:21 am
(@kris-morgan)
Posts: 3876
 

Geezer, post: 325857, member: 466 wrote: I am using a Promark 500, getting correctors from ODOT for RTK in the RTH ORGN OCRS an Zone.
(From that, it should be no shock that I don't know what I am doing).

Regardless of that, my question is this, "How concerned should I be to have the antenna pointed to the North?

thanx,
Geezer

Once upon a time, it was needed (or at least it was said that it was). Now, not so much. I still make my base station antenna's point North, but otherwise, I do not worry about it and I haven't seen it help or hurt anything.

 
Posted : July 6, 2015 4:09 am
(@dmyhill)
Posts: 3082
Member
 

Geezer, post: 325857, member: 466 wrote: I am using a Promark 500, getting correctors from ODOT for RTK in the RTH ORGN OCRS an Zone.
(From that, it should be no shock that I don't know what I am doing).

Regardless of that, my question is this, "How concerned should I be to have the antenna pointed to the North?

thanx,
Geezer

All sorts of design differences can create a different center point for an antenna or antenna/receiver...

Here is the NGS jargon for yours:

http://www.ngs.noaa.gov/ANTCAL/LoadFile?file=MAG990596_NONE.atx

The offsets are very small...

 
Posted : July 6, 2015 2:27 pm