LPS: Station Setup by Resection

  • Before any station setup, you will need to ensure the following:
    • LPS_Setup program is installed on the instrument
    • Units are set on the instrument
    • A control file is loaded into LPS_Setup
  • Now, go to Station Setup Wizard.
  • The Setup method has three options in the dropdown box.  This example will use New station by resection.
  • This method places the instrument on an unknown point with a line of sight to at least two control points.
  • The map to the right shows an example of a resection.  The red triangles are backsights while the yellow triangle is the instrument.
  • With the instrument setup over a control point, use a tape measure to measure the slant height from the control point to the vertical center of the instrument.  This is the pivot point of the collimator.  Most instruments will have a small mark on the side to measure to.
  • This height is entered into the Instrument height field on the total station.
  • Now, tap the Next button.
  • A resection will require at least two backsight shots.  To start the first backsight shot, tap the Add... button.
  • Tap the Point Name: button to define the first control point.  For this example, CP-1 is used.
  • Once the backsight prism is setup over the control point, sight the instrument to the prism.  Enter the correct height and Prism Constant (PC) values and hit the Observe button.
  • After the shot has been taken, there should now be values in the H.Angle, V.Angle and S.Dist fields.
  • Tap the OK button to continue to the next backsight.
  • Tap the Add button to start the second backsight.  For this example, Pole 1 will be used.
  • This time, the prism height and PC are changed as a different style of prism is used.  Sight the instrument on the prism and tap the Observe button.  HA/VA/SD numbers should now be shown in their respective fields.
  • Tap the OK button to store that backsight.
  • If the horizontal, vertical and distance measurements are used on both points, only two backsights are required.  If only horizontal or horizontal and vertical are used, a third backsight is required.
  • LPS_Setup will give a warning that resection setup requires one of the following scenarios:
    • More than 3 pts: Three points using any combination of H/V/D observations
    • 3 pts with one measured distance: Three backsights with one distance observation used
    • 2 pts both with measured distance: Two backsights that both used the distance observations

 

  • Once LPS_Setup has a proper resection solution, you will see a screen that shows the computed station values.  Tap the Next button to proceed to the Station coordinate screen.
  • The North/East/Elev values here are the computed values based off the resection shots.
  • LPS_Setup will give you the option to save this computed point for future use.  For this example, the point has been saved as RS01.
  • By saving this point, you will be able to use it as a resection or backsight point in the future.  The North/East/Elev values and point name are amended to the control point file.