Why is the Vertical angle of my total station changing depending on the Horizontal angle? 

Professional Surveyor Boards » Ask an Expert » Why is the Vertical angle of my total station changing depending on the Horizontal angle?

Name Message
level headed
Posts: 1

Joined: 7/26/2012
Topic  Why is the Vertical angle of my total station changing depending on the Horizontal angle?       Flag »  Reply »

Recently I have performeda series of surveys and I have started to question the accuracy of individualface left measurements due to the fact that the vertical (Vt) angle of thetotal station that I am using changes depending on where I aim it even though Ihave not touched the telescope.

At first I thought that this may be the dualaxis compensator at work correcting for minor errors in the level of the stationbut in this case should my display not show a constant Vt angle?

The stationalways returns to the same Vt measurement when returned to the same Hz anglesuggesting a systematic error in the station is there any way to modal it andremove it from previous readings? is this a common error? 

Does any one know of any literature that covers this problem ?


Thanks 

  Thursday, July 26, 2012 at 9:49:35 PM
surveyNB
Posts: 1
Location: , canada

Joined: 9/26/2012
Reply  Re: Why is the Vertical angle of my total station changing depending on the Horizontal angle? Flag »  Reply »
This is due to the total station not being exactly level and the compensator doing its job.  If you happened to get the gun set up perfect and the instrument was made perfectly then you would see that the vertical angle would not change.  This is near impossible and therefore we have compensators to correct for this.  As you spin the scope around the horizon it is not spinning around an axis that is exactly orthogonal to the gravitational field so it will have different vertical angles as you go around.  This can be used to help level the instrument as well.  Set the vertical angle to 90 and turn the gun 180 degrees around.  It should be 90 as well but most likely won't be.  Adjust your foot screws until you split the difference.  Do this again 90 degrees off of this line.  This is the most accurate way to level your total station.  Once you do this you should then be able to spin the gun freely and it should stay at the same vertical angle.
  Wednesday, September 26, 2012 at 10:38:58 PM

Professional Surveyor Boards » Ask an Expert » Why is the Vertical angle of my total station changing depending on the Horizontal angle?

 
» Reply to Why is the Vertical angle of my total station changing depending on the Horizontal angle? Topic

In order to post a new message, you must first be logged into an account.

Website design and hosting provided by 270net Technologies in Frederick, Maryland.