Topcon OS Series User manual

TOPCON OS SERIES TOTAL STATION AND MAGNET FIELD
OS Series Resection Setup Quick Guide
This Quick Guide is to show you how to setup and orientate the Topcon OS Series Total
Station using the Resection Method.
Principles of a Resection:
Resection is used to determine the coordinates of an instrument position (station point) by
performing multiple measurements of points whose coordinate values are known.
We need a minimum of two known points to perform a
resection, but the more points that are known and
used, the higher the precision of the calculated
instrument position. We would always recommend a
minimum of three known points to be used.
In this diagram you can see the Instrument is setup at
P0 and we have known points at positions P1 to P4.
We are going to use P1, P2 and P3 for our resection.
It is important to make sure that the battery is seated in the instrument prior to setting
the Total Station up as the weight of the battery will affect the level of the instrument.
Step One: Positioning the Instrument
1) Locate a position where you can observe at least two known
control points.
Make sure the Tripod legs are spaced at equal intervals and the
Tripod head is roughly level.
Make sure the Tripod feet are firmly fixed in the ground.
Tip: Set the height of the Tripod head at mid chest height to
ensure the telescope of the instrument is at eyelevel.
2) Place the Instrument on the Tripod head.
Supporting it with one hand, tighten the centring screw on the
bottom of the unit to make sure it is secured to the Tripod.

Step Two: Levelling
1) Centre the bubble in the circular level by either shortening the
Tripod leg closest to the off-centre direction of the bubble or by
lengthening the Tripod leg farthest away from the off-centre
direction of the bubble. Adjust one more Tripod leg to centre
the bubble.
Turn the levelling foot screws while checking the circular level
until the bubble is centred in the centre circle.
2) Turn on the OS Series using the Power Button.
The “Virtual Bubble” is shown on the screen.
“” indicates the bubble in the circular level.
3) Centre “” in the Circular level.
4) Turn the Instrument until the telescope is parallel
To a line between levelling foot screws A and B.
5) Set the tilt angle to 0˚ using foot screws A and B for the X direction and levelling screw
C for the y direction Remember Fingers and Thumbs! Always turn A and B in opposite
directions to half the error on each foot screw.
6) Press {ESC} on the instrument keypad to return to observation mode.
7) If the instrument does not automatically open the MAGNET Field software, press
{PRG} on the instrument keypad.
Select “MAGNET Field” from the listed programs
The remainder of the Resection setup procedure is completed using MAGNET Field.

Resection Setup using MAGNET Field on the Topcon OS
1) From the MAGNET Field home
screen, select the [Setup]
Option.
2) From the Setup options select
the [Resection] icon.
3) Define Instrument Setup:
We need to enter a unique ID for
the point the Total Station is
setup on. In this case P0.
There is no need to enter the
Height of the Instrument (HI).
Tap the [Next >>] Icon
4) MAGNET Field now asks you to
specify your first control point, in
this case “P1”. You can select
the point from the map or list
icons or manually enter the ID.
If the point is not in the
Database you will be taken to
the “Add Point” Screen. Enter
your Prism Height (0m in this
example)
Sight the Instrument on your
target and tap the “Measure” Icon.

5) MAGNET Field will now ask you
to specify another control point,
in this case P2. As before you
can select from the map, list or
manually enter. Don’t forget to
enter your pole height!
Tap the “Measure” Icon
6) MAGNET Field will now take you
to the results screen which will
show you the residuals from
your initial two measurements.
We could accept this result by
tapping the [Accept] icon, but we
recommend adding a third
known point. To add a third
point, tap the [Add] icon.
7) MAGNET Field will take you to
the same screen we saw in step
5, we have selected known point
P3 (Don’t forget pole height!) and
tapped the “Measure”
icon.
8) MAGNET Field returns us to our
results screen and we can now
check our residuals, in this case,
EN and Z values are all zero,
which is a perfect result. In the
field, an error of a few mm is
perfectly normal.
We can check the individual
results in the table and if needed,
we can remove the measurement
by highlighting and tapping the
[Remove] icon, or remeasure by tapping the [Re-Meas] icon. If you are happy with
your result, tap the [Home] Icon to the top right of the screen and you will be returned
to the home screen, setup and orientated and ready to survey or stake out.
End.