NOTES ON TOTAL STATION-INTRODUCTION,COMPONENTS,WORKING

ANU JOHNSON 1
MODULE -3
ELECTRONIC THEODOLITE
TOTAL STATION

ANU JOHNSON 2
TOTAL STATION
 A TOTAL STATION IS AN ELECTRONIC / OPTICAL INSTRUMENT USED
IN MODERN SURVEYING .THE TOTAL STATION IS AN ELECTRONIC
THEODOLITE (TRANSIT) INTEGRATED WITH AN ELECTRONIC
DISTANCE METER (EDM) TO READ SLOPE DISTANCES FROM THE
INSTRUMENT TO A PARTICULAR POINT.

3
 AS THE INSTRUMENT COMBINES BOTH ANGLE AND DISTANCE MEASUREMENT IN
THE SAME UNIT ,IT IS ALSO KNOWN AS AN INTEGRATED TOTAL STATION WHICH
CAN MEASURE HORIZONTAL AND VERTICAL ANGLES AS WELL AS SLOPE
DISTANCES.
 USING THE VERTICAL ANGLE ,THE TOTAL STATION CAN CALCULATE THE
HORIZONTAL AND VERTICAL DISTANCE COMPONENTS OF THE MEASURED SLOPE
DISTANCE.
 IN ADDITION TO THE BASIC FUNCTIONS IT CAN PERFORM A NUMBER OF SURVEY
TASKS AND ASSOCIATED CALCULATIONS AND CAN STORE LARGE AMOUNTS OF
DATA.
 ALL THE FUNCTIONS OF A TOTAL STATION ARE CONTROLLED BY ITS
MICROPROCESSOR ,WHICH IS ACCESSED THROUGH A KEYBOARD AND A DISPLAY.
 TO USE THE TOTAL STATION ,IT IS SET OVER ONE END OF THE LINE TO BE
MEASURED AND SOME REFLECTOR IS POSITIONED AT THE OTHER END SUCH THAT
THE LINE OF SIGHT BETWEEN THE INSTRUMENT AND THE REFLECTOR IS
UNOBSTRUCTED.
ANU JOHNSON

4
 THE REFLECTOR IS A PRISM ATTACHED TO A DETAIL POLE
 THE TELESCOPE IS ALIGNED AND POINTED AT THE PRISM
 THE MEASURING SEQUENCE IS INITIATED AND A SIGNAL IS SENT TO THE
REFLECTOR AND A PART OF THIS SIGNAL IS RETURNED TO THE TOTAL
STATION
 THIS SIGNAL IS THEN ANALYZED TO CALCULATE THE SLOPE DISTANCE
TOGETHER WITH THE HORIZONTAL AND VERTICAL ANGLES
 TOTAL STATIONS CAN ALSO BE USED WITHOUT REFLECTORS AND THE
TELESCOPE IS POINTED AT THE POINT THAT NEEDS TO BE MEASURED
 SOME INSTRUMENTS HAVE MOTORIZED DRIVERS AND CAN BE AUTOMATIC
TARGET RECOGNITION TO SEARCH AND LOCK THE PRISM-THIS IS A FULLY
AUTOMATED PROCESS AND DOES NOT REQUIRE AN OPERATOR
 SOME TOTAL STATIONS CAN BE CONTROLLED FROM THE DETAIL
POLE ,ENABLING SURVEYS TO BE CONDUCTED BY ONE PERSON
ANU JOHNSON

ANU JOHNSON 5
MODELS OF TOTAL STATION
SOKKIA
LEICA
TRIMBLE
TOPCON

ANU JOHNSON 7
SETTING UP OF TOTAL STATION
 STEP-1: TRIPOD SET UP
TRIPOD LEGS SHOULD BE EQUALLY SPACED .TRIPOD HEAD SHOULD BE
APPROXIMATELY LEVEL.HEAD SHOULD BE DIRECTLY OVER SURVEY
POINT.

ANU JOHNSON 8
 STEP-2: MOUNT INSTRUMENT ON TRIPOD
PLACE INSTRUMENT ON TRIPOD .SECURE WITH CENTERING SCREW
WHILE BRACING THE INSTRUMENT WITH THE OTHER HAND.INSERT
BATTERY IN INSTRUMENT BEFORE LEVELLING.

ANU JOHNSON 9
 STEP 3: FOCUS ON SURVEY POINT
FOCUS THE OPTICAL PLUMMET ON THE SURVEY POINT

ANU JOHNSON 10
 STEP 4: LEVELLING THE INSTRUMENT
ADJUST THE LEVELLING FOOT SCREWS TO CENTER THE SURVEY POINT IN
THE OPTICAL PLUMMET RETICLE.CENTER THE BUBBLE IN THE CIRCULAR
LEVEL BY ADJUSTING THE TRIPOD LEGS.

ANU JOHNSON 11
 STEP 5: LEVELLING
LOOSEN THE CLAMP AND TURN INSTRUMENT UNTIL PLATE LEVEL IS
PARALLEL TO 2 OF THE LEVELLING FOOT SCREWS.CENTER THE BUBBLE
USING THE LEVELLING SCREWS –THE BUBBLE MOVES TOWARD THE
SCREW THAT IS TURNED CLOCKWISE.ROTATE THE INSTRUMENT 90
DEGREES AND LEVEL USING THE 3RD
LEVELLING SCREW .OBSERVE THE
SURVEY POINT IN THE OPTICAL PLUMMET AND CENTER THE POINT BY
LOOSENING THE CENTERING SCREW AND SLIDING THE ENTIRE
INSTRUMENT.AFTER RE-TIGHTENING THE CENTERING SCREW CHECK TO
MAKE SURE THE PLATE LEVEL BUBBLE IS LEVEL IN SEVERAL
DIRECTIONS.

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 STEP 6: ELECTRONICALLY VERIFY LEVELLING
ANU JOHNSON

ANU JOHNSON 13
 STEP 7: ADJUST IMAGE & RETICLE FOCUS
RELEASE THE HORIZONTAL & VERTICAL CLAMPS AND POINT TELESCOPE
TO A FEATURELESS LIGHT BACKGROUND .ADJUST THE RETICLE (i.e.;
CROSS HAIR) FOCUS ADJUSTMENT UNTILL RETICLE IMAGE IS SHARPLY
FOCUSSED.POINT TELESCOPE TO TARGET AND ADJUST THE FOCUS RING
UNTIL TARGET IS FOCUSED.MOVE YOUR HEAD FROM SIDE-TO-SIDE TO
TEST FOR IMAGE SHIFT(i.e. parallax) .REPEAT THE RETICLE FOCUS STEP IF
PARALLAX IS SIGNIFICANT.
NOTE:WHEN THE INSTRUMENT OPERATOR CHANGES THE RETICLE FOCUS
MAY NEED TO BE ADJUSTED.

ANU JOHNSON 14
PRINCIPLE USED IN E.D.M. INSTRUMENTS
THE PRINCIPLE USED IN E.D.M. INSTRUMENTS IS THAT THE DIFFERENCE IN
PHASE BETWEEN THE TRANSMITTED AND RECEIVED WAVES REPRESENTS
ONLY A FRACTION OF THE WAVELENGTHS AND THAT BY USING SEVERAL
WAVELENGTHS OF VARYING FREQUENCIES THE DISTANCE CAN BE
MEASURED .
DISTANCE (D) = VELOCITY x TIME = v x t
THE ELECTROMAGNETIC WAVES ARE TRANSMITTED TO A RETRO
REFLECTOR WHICH RETURNS THEM TO THE TRANSMITTING
INSTRUMENT .THE INSTRUMENT MEASURES PHASE SHIFT. BY COMPARISON
OF THE PHASE SHIFT BETWEEN THE TRANSMITTED AND REFLECTED
SIGNALS THE TIME AND THUS THE DISTANCE CAN BE DETERMINED.

ANU JOHNSON 15
APPLICATIONS OF TOTAL STATION
 UPDATING MAPPING
 TOPOGRAPHIC SURVEY
 HYDROGRAPHIC SURVEY
 CADASTRAL SURVEY
 PROJECT CONSTRUCTION SURVEY
 ROAD ,RAILWAY SURVEY
 MINING SURVEY
 DEFENCE
 ENGINEERING SURVEY

MEASUREMENT OF HORIZONTALAND VERTICAL
ANGLE
 SET UP THE INSTRUMENT OVER A STATION (SAY O)
 CENTRE IT ACCURATELYAND LEVEL IT
 PRESS THE POWER BUTTON TO SWITCH ON THE INSTRUMENT
 SELECT MODE A D-30
 PRESS ‘DIS’ TWICE TO GET THE PAGE WHICH CONSISTS OF ALL HORIZONTAL AND VERTICAL
MEASUREMENTS
 TURN THE TOTAL STATION TO POINT P .FOCUS IT AND BISECT IT EXACTLY USING VERTICAL
AND HORIZONTAL CLAMP
 SET THE HORIZONTAL AS 0 BY DOUBLE CLICKING ON OSET(F3)
 THEN RELEASE THE HORIZONTAL AND VERTICAL CLAMP AND TURN THE TOTAL STATION TO
THE POINT Q WHERE THE REFLECTING PRISM IS FIXED
 BISECT THE PRISM EXACTLYAND PRESS MEAS(F1)
 THEN THE DISPLAY PANEL WILL SHOW ALL THE VERTICAL AND HORIZONTAL
MEASUREMENTS
ANU JOHNSON 16
P
O
Q
P
Q
O

ANU JOHNSON 17
CALCULATION OF AREA USING TOTAL STATION
 FIX THE TOTAL STATION OVER A STATION AND LEVEL IT
 PRESS THE POWER BUTTON TO SWITCH ON THE INSTRUMENT
 SELECT MODE B--->S FUNCTION--->FILE MANAGEMENT--->CREATE (ENTER A NAME)
--->ACCEPT
 THEN PRESS ESC TO GO TO THE STARTING PAGE
 THEN SET 0 BY DOUBLE CLICKING ON 0 SET (F3)
 THEN GO TO S FUNCTION--->MEASURE--->RECTANGULAR CO-ORDINATE--->STATION
--->PRESS ENTER
 HERE ENTER THE POINT NUMBER OR NAME ,INSTRUMENT HEIGHT AND PRISM
CODE
 THEN PRESS ACCEPT (Fs)

ANU JOHNSON 18
 KEEP THE REFLECTING PRISM ON THE FIRST POINT AND TURN THE TOTAL
STATION ON THE PRISM ,FOCUS IT AND BISECT IT EXACTLY USING A
HORIZONTAL AND VERTICAL CLAMPS
 THEN SELECT MEAS AND THE DISPLAY PANEL WILL SHOW THE POINT
SPECIFICATION
 NOW SELECT EDIT AND RE-ENTER THE POINT NUMBER OR NAME POINT CODE
AND ENTER THE PRISM HEIGHT THAT WE HAVE SET
 THEN PRESS MEAS/SAVE (F3) SO THAT THE MEASUREMENT TO THE FIRST
POINT WILL AUTOMATICALLY BE SAVED AND THE PANEL WILL SHOW THE
SECOND POINT
 THEN TURN THE TOTAL STATION TO SECOND POINT AND DO THE SAME
PROCEDURE
 REPEAT THE STEPS TO THE REST OF THE STATIONS AND CLOSE THE TRAVERSE

ANU JOHNSON 19
 NOW GO TO S FUNCTION--->VIEW/EDIT--->GRAPHICAL VIEW
 IT WILL SHOW THE GRAPHICAL VIEW OF THE TRAVERSE
 SELECT S FUNCTION--->CALCULATION--->2D SURFACE--->ALL--->ACCEPT
 THIS WILL GIVE THE AREA OF THE CLOSED TRAVERSE

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Objectives of Using Total Station
The major objectives of using the total station in surveying
can be listed as follows:
a. To determine the angles between the points or average
of the multiple angles measured.
b. To determine the horizontal distance between the points
or average of the multiple distances measured.
c. To determine the elevation of various points.
d. To determine all three coordinates of various points
ANU JOHNSON

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Operations Performed by a Total Station
The important operations that can be performed using a total
station can be listed as follows:
a. Measurement of Distance
An essential component of the total station is Electronic Distance
Measuring (EDM) which is responsible for the distance
measurement.
The measuring range of the EDM can vary from 2.8km to 4.2km.
A typical EDM is capable of measuring the distance with an
accuracy ranging between 5mm to 10mm per km of measurement.
The EDM is equipped with an automatic target recognizer. The
distance measured by the total station is always the sloping
distance from the instrument station to the object.
ANU JOHNSON

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b. Measurement of Angle
Another important operation performed by the total station is the measurement of
angle.
Usually, any suitable direction must be taken as the reference direction for the
measurement of the horizontal angles.
While, in the case of the vertical angles, the vertically upward direction i.e. the
zenith is taken as the reference direction.
c. Processing of Data
The processing of data in the total station is done utilizing the microprocessor that
is inbuilt into it.
The inbuilt microprocessor is capable of averaging the multiple observations taken.
The microprocessor can compute the horizontal distance as well as the location
coordinates (X, Y, Z).
In the modern total station, the microprocessor can apply even the pressure
corrections and the temperature corrections when the temperature and the pressure
values are provided.
ANU JOHNSON

ANU JOHNSON 23
d. Display of Output
The output or the computed results are displayed in the total station
utilizing the electronic display unit.
The display unit can display the computed horizontal distance, vertical
distance, horizontal and vertical angles, elevation differences between
points, and the location coordinates of the required points.
e. Electronic Record-Keeping (Electronic Book)
The total station is capable of storing the data in an electronic book
which is similar to a compact disc of the computer.
Such an electronic book can store data ranging from 2000 points to
4000 points.
The data stored in the electronic book of the total station can be
unloaded by the surveyor to a computer

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Data gathering and data processing
 Data Collector
As the name itself implies, the data collector collects and stores the observed data
or observations.
The entire operation of taking in and storing the data is controlled by the data
collector.
The data collector stores the data either in binary form or ASCII.
Data collectors can be further divided into external data collectors and internal
data collectors.
 Memory
The total station is equipped with inbuilt memory cards to process and store the
data or observations.
The memory card provided in the total stations is generally up to the PCMCIA
standards.
The memory card can have a capacity ranging from 5000 to 10,000 coded points.
The data held by the memory card can be unloaded on any computing device.

25
 Reflector
The reflector is one of the most essential accessories of the total station. This is
because the total station functions or takes the measurements utilizing the
reflected rays.
The reflector comprises a specially built reflecting prism made up of cubes or
blocks of reflecting glasses.
Data processing
Some models include internal electronic data storage to record distance,
horizontal angle, and vertical angle measured, while other models are equipped
to write these measurements to an external data collector, such as a hand-held
computer.
When data is downloaded from a total station onto a computer, application
software can be used to compute results and generate a map of the surveyed area.
The newest generation of total stations can also show the map on the touch-
screen of the instrument immediately after measuring the points.
Software
In most of the total stations, the operating system used is Windows CE.

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Suitability of Total Station
It is desirable to use a total station in surveying when any of the following conditions
exist:
a. When two points have been provided.
b. When only one of the coordinates has been provided.
c. When no coordinates have been given and arbitrary sets of coordinates have to be used.
Accuracy of Total Station
The accuracy of a total station depends on the type of total station used. It is the degree of
closeness between the measured value and the actual value.
Usually, the angular accuracy of a total station ranges from 1” to 20”.
The distance accuracy mainly depends upon the instrumental error and the error due to the
length of measurement.
The instrumental error may vary between +/- 10mm to +/- 2mm.
The error due to the length of measurement may vary between +/- 10mm to +/- 2mm per
kilometer in case of 1 prism, 2.5 to 2.7 km in case of two prisms & 5 to 7 km in cases of 3
prisms.
Least Count of a Total Station
In the total station; the least count of the angle is 1” (1 second) and the least count of
distance is 1 mm

27
Advantages of Total Station
The total station offers the following major advantages:
a. The total station helps to complete the fieldwork quickly in a lesser period.
b. The setting up of the total station is also easier as it can be done easily by using the laser plummet.
c. The degree of accuracy of the total station is relatively higher than other survey instruments.
d. The computed values can be directly stored in the total station and can also be easily transferred to a
computing device.
e. The total station is also advantageous in the computerization of old maps.
f. Since all the observations and computations are done digitally, error due to omission of data, wrong
reading or noting of observation, etc is omitted.
g. It can also help in contouring and map preparation.
h. When the atmospheric pressure and temperature are provided, the pressure and temperature corrections
can also be applied automatically.
i. The entire survey work and office work can be completed easily.
Disadvantages of Total Station
Some of the disadvantages of the total station can be listed as follows:
a. While using the total station, it may be difficult for the surveyor to recheck the work.
b. Skilled manpower or experienced personnel is required for operating the instrument.
c.The total station is costlier than other conventional survey equipment.
d. The total station is incorporated with several electronic accessories and parts that may be affected by
moisture

28
SOURCES OF ERROR FOR TOTAL STATIONS
1 .CALIBRATION OF TOTAL STATIONS
To maintain the high level of accuracy offered by modern total stations, there is now much more
emphasis on monitoring instrumental errors, and with this in mind, some construction sites require
all instruments to be checked on a regular basis using procedures outlined in the quality manuals
Some instrumental errors are eliminated by observing on two faces of the total station and
averaging, but because one face measurements are the preferred method on site, it is important to
determine the magnitude of instrumental errors and correct for them.
For total stations, instrumental errors are measured and corrected using electronic calibration
procedures that are carried out at any time and can be applied to the instrument on site. These are
preferred to the mechanical adjustments that used to be done in labs by technician.
Since calibration parameters can change because of mechanical shock, temperature changes and
rough handling of what is a high-precision instrument, an electronic calibration should be carried
our on a total station as follows:
Before using the instrument for the first time
After long storage periods
After rough or long transportation
After long periods of work
Following big changes in temperature
Regularly for precision surveys
Before each calibration, it is essential to allow the total station enough to reach the ambient

29
2. HORIZONTAL COLLIMATION (OR LINE OF SIGHT
ERROR)
This axial error is caused when the line of sight is not perpendicular to
the tilting axis. It affects all horizontal circle readings and increases with
steep sightings, but this is eliminated by observing on two faces. For
single face measurements, an on-board calibration function is used to
determine c, the deviation between the actual line of sight and a line
perpendicular to the tilting axis. A correction is then applied
automatically for this to all horizontal circle readings.
2 HORIZONTAL COLLIMATION (OR LINE OF SIGHT ERROR)
This axial error is caused when the line of sight is not perpendicular to the tilting
axis. It affects all horizontal circle readings and increases with steep sightings, but
this is eliminated by observing on two faces. For single face measurements,
an on-board calibration function is used to determine c, the deviation between the
actual line of sight and a line perpendicular to the tilting axis. A correction is then
applied automatically for this to all horizontal circle readings.

30
3 .TILTING AXIS ERROR
This axial errors occur when the titling axis of the
total station is not perpendicular to its vertical axis.
This has no effect on sightings taken when the
telescope is horizontal, but introduces errors into
horizontal circle readings when the telescope is
tilted, especially for steep sightings. As with
horizontal collimation error, this error is eliminated
by two face measurements, or the tilting axis error a
is measured in a calibration procedure and a
correction applied for this to all horizontal circle
readings - as before if a is too big, the instrument
should be returned to the manufacture.
ANU JOHNSON
error, this error is eliminated by two face measure
is measured in a calibration procedure and a co
horizontal circle readings - as before if a is too
returned to the manufacture.

31
4 .COMPENSATOR INDEX ERROR
Errors caused by not levelling a theodolite or total station
carefully cannot be eliminated by taking face left and face right
readings. If the total station is fitted with a compensator it will
measure residual tilts of the instrument and will apply corrections
to the horizontal and vertical angles for these.
However all compensators will have a longitudinal error l and
traverse error t known as zero point errors. These are averaged
using face left and face right readings but for single face readings
must be determined by the calibration function of the total station.
A vertical collimation error exists on a total station if the 0o
to
180o
line in the vertical circle does not coincide with its vertical
axis. This zero point error is present in all vertical circle readings
and like the horizontal collimation error, it is eliminated by taking
FL and FR readings or by determining i
ANU JOHNSON

32
For all of the above total station errors (horizontal and vertical collimation, tilting
axis and compensator) the total station is calibrated using an in built function. Here
the function is activated and a measurement to a target is taken as shown below.
Following the first measurement the total station and the telescope are each
rotated through 180o and the reading is repeated.
Any difference between the measured horizontal and vertical angles is then
quantified as an instrumental error and applied to all subsequent readings
automatically. The total station is thus calibrated and the procedure is the same for
all of the above error type.

33
Keyboard, Display and Software Applications in Survey
Total Station
A total station is activated through its control panel, which
consists of a keyboard and multiple line LCD. A number of
instruments have two control panels, one on each face, which
makes them easier to use.
KEYBOARD AND DISPLAY
A total station is activated through its control panel, which
consists of a keyboard and multiple line LCD. A number of
instruments have two control panels, one on each face, which
makes them easier to use.
In addition to controlling the total station, the keyboard is
often used to code data generated by the instrument - this code
will be used to identify the object being measured.
On some total stations it is possible to detach the keyboard
and interchange them with other total stations and with GPS
receivers. This is called integrated surveying .

34
SOFTWARE APPLICATIONS
The microprocessor built into the total station is a small computer and its main function is
controlling the measurement of angles and distances. The LCD screen guides the operator while
taking these measurements.
The built in computer can be used for the operator to carry out calibration checks on the
instrument.
The software applications available on many total stations include the following:
1. Slope corrections and reduced levels
2. Horizontal circle orientation
3. Coordinate measurement
4. Traverse measurements
5. Resection (or free stationing)
6. Missing line measurement
7. Remote elevation measurement
8. Areas Setting out.
Although all manufacturers quote ranges of several kilometres to a single prism.
For those construction projects where long distances are required to be measured, GPS methods
are used in preference to total stations. There is no standard difference at which the change from
one to the other occurs, as this will depend on a number of factors, including the accuracy
required and the site topography

NOTES ON TOTAL STATION-INTRODUCTION,COMPONENTS,WORKING

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