Total station is a combination of an electronic theodolite and an electronic distance measurement device. It can determine coordinates of a reflector by measuring vertical and horizontal angles and slope distances to the reflector. It has components like EDM to measure distances, an electronic theodolite to measure angles, a microprocessor to record readings and perform computations, and a data collector to transfer data to a computer. Accuracy depends on the instrument and can range from 1-5 seconds for angles and 1-3mm + ppm*D for distances. Total stations can be used to perform functions like determining coordinates, measuring distances and angles, topographic surveying, traverse adjustment, resection, and remote elevation measurements.

1. Total Station
Highway Engineering Dept.
Lecture 6 Prepared by: Razhan Sherwan

2. What is Total station
The total station is an improvised version of modern surveying
instruments such as EDM – Electronic distance measurement,
auto level and digital level.
Total station is a combination of an electronic theodolite and an
electronic distance measurement (EDM).
This combination makes it possible to determine the coordinates
of reflector by aligning the instrument’s cross hair on the
reflector and simultaneously measuring the vertical and
horizontal angles and slope distances.
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3. Components of Total Station
1EDM (electronic distance measurement) is used to compute
distance between the instrument and the reflector or a target.
2Electronic theodolite: it is used to compute directions and
measure horizontal and vertical angle.
3On-board micro processor: It takes care of recording,
readings and the necessary computations.
4 Data collector: The data can be easily transferred to a
computer where it can be used to compute measurements.
5 Data Storage: to store collected data
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4. Components of Total Station
6 Prism (and prism pole)
7 Computer interface
8 Batteries and radios
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5. Total station accuracy
 the accuracy of a total station is dependent on instrument type.
 Angle Accuracy (Horizontal or Vertical) can range from 2” to 5”.
 Distance Accuracy can range from:
+/- (0.8 + 1 ppm x D) mm
to +/- (3 + 3 ppm x D) mm
where D = distance measured
 Accuracy is highly dependent on leveling the instrument.
Thus two
leveling bubbles are provided on the instrument and are referred to
the circular level and the plate level.
Circular level is located on the tri-brach while plate level is on
horizontal axis of instrument just below
scope of the total station.
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6. More accuracy can be achieve by :
1. Careful Centering
2. Accurate pointing target
3. Average of multiple points
4. Better optical lense
5. Strong Tripod
6. Verticality of prism pole
1. Angular accuracy is from 1 to 20 Sec.
2. Linear accuracy is from 2mm to 10mm/per KM
3. Different instruments have different accuracy
Angular
Linear
With 1 Prism With 3 prisms
NIKON 1 Sec + 2 mm + 1 mm
LIEKA 1 Sec + 2 mm + 1 mm
CHC 2 Sec 2 mm + 1 mm
Total station accuracy

7. Types of Total Station
1- Digital Total Station: A form of an electronic theodolite
combined with an electronic distance measuring device
(EDM).
• the primary function is to measure slope distance, vertical angle,
and horizontal angle from a setup point to a targeted point.
• Angle Accuracy (Horizontal or Vertical) can range from 2” to 5”
• Accuracy is highly dependent on leveling the instrument.
Thus two leveling bubbles are provided on the instrument
and are referred to the circular level and the plate level
• Sensitivity of Circular Level = 5’ / 1mm
• Sensitivity of Plate Level = 15” / 1mm
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8. Types of Total Station
2- Reflector-less Total Station: Reflector-less total stations
can measure distances to any object that is reasonably light in
color, up to a few hundred meters.
• The range, accuracy and other specifications may vary
slightly, but all are sufficient for use on the job site.
Benefits
• The main advantage of reflector-less total station is the
ability to measure inaccessible points.
• Reduce manpower
• Reduce time consuming
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9. Types of Total Station
Drawbacks of reflector-less Total station:
1 Range measurement is limited.
2Reflector uncertainty: It is a situation when the laser
beam is reflected off something other than what it was
supposed to read or targeted.
3Incidence angle measurement: The reference point for
measuring the distance is shifted and not well-defined because
of the distortion of the footprint.
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10. Types of Total Station
3-Robotic Total Station: The developed total station by
name robotic total station allows the operator to control the
instrument from a distance via remote control.
This eliminates the need of an assistant staff member, as the
operator holds the reflector and controls the total station from the
observed point.
Video
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11. Types of Total Station
Advantages of Robotic total station:
1-No need of operator on station
2-Display at target also
3 Move automatically to predetermined direction and focuses
automatically at target.
4 Can be integrated with GPS also
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12. Types of Total Station
4-Smart Total Station:
• It is a high performance total station that integrates perfectly
a powerful GPS receiver.
•It is easy to use, no need for control points, long
traverses or resections and known points Just set up the
Smart-Station and let the GPS determine the position of
the total station.
• You survey easier, quicker and with fewer set ups
•All data are stored in the same database on the
Same SD card, USB memory stick or internal memory.
•All measurements, status and other information are
displayed on the TS screen.
• No need for cables, external battery, data logger etc…………..
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13. Factors Influencing On Total Station
1A clear line of sight between the instrument and the measured
points is required.
2 the precision of the instrument is depend on the raw
repeatabilities of the direction and distance measurements.
3A well defined measurement point or target/prism is required
to obtain optimal precision and accuracy.
4To achieve high precision measurements, all scale factors and
codes should be imported.
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14. Advantages of Total Station
1. Most accurate and user friendly.
2. Gives position of a point (x, y and z) with respect to
known point (base point).
3. EDM is fitted inside the telescope.
4. It has digital display and on board memory to store data
and compatibility with computers.
5. Measures distance and angles and displays coordinates,
6. Auto level compensator is available.
7. Can work in lesser visibility also.
8. Can measure distances even without prismatic target for
lesser distances.
9. On board software are available.
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15. Advantages of Total Station
10. Relatively quick collection of information
11. Multiple surveys can be performed at one set-up location.
12. Layout of construction site quickly and efficiently.
13.Digital design data from CAD programs can be uploaded
to data collector.
14.Daily survey information can also be quickly downloaded
into CAD which eliminates data manipulation time required
using conventional survey techniques.
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16. Limitations
1.It is not a Rugged instrument (Sensitive).
2.Prism verticality is necessary.
3.Visibility is must.
4.More Expensive.
5.Requires calibration at every six months and online update.
6.Amount of error is greater at short distances. No less than 3m
7.Height of instrument and prism is to be imported.
8. Awareness on battery maintenance.
9. To establish north- compass is required. (No for smart
stations)
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17. Limitations
10Vertical elevation accuracy not as accurate as using
conventional survey level and rod technique.
11Horizontal coordinates are calculated on a rectangular
grid system. However, the real world should be based on a
spheroid and rectangular coordinates must be transformed
to geographic coordinates if projects are large scale.
Examples : highways, large buildings, etc.
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18. Functions Of Total Station
1-Coordinates determination
Total station determines the coordinates of an unknown point
relative to the known coordinate by establishing a direct line
of sight between the two points.
Angles and distances are measured from the total station to
points under survey and the coordinates of surveyed points
relative to the total station position are calculated using
trigonometry and triangulation.
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19. From bearing and distance to
horizontal coordinates
For the computation of the horizontal coordinates of B we:
• know horizontal coordinates of A(EA,NA)
• measure horizontal distance LAB and WCB αAB
• compute horizontal coordinates B(EB,NB)
Computations
NB=NA+∆N=NA+LAB X cosαAB
EB=EA+∆E=EA+LAB X sinαAB
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20. Example
We have
•a point A of known coordinates EA=1034.148m
NA=2396.941m) and
We can measure
• The WCB αAB=42° 36’ 24” and distance LAB=326.428m
Compute: The coordinates of point B (EB, NB)
EB= 1034.148 + 326.428×sin 42.6067 = 1255.127
NB = 2396.941 + 326.428×cos 42.6067 = 2637.197
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21. From known coord to
bearing and distance
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22. Example
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23. Functions Of Total Station
2-Distance measurement
A total station has a small solid state emitter within the
instrument’s optical path. They generate modulated
microwave or infrared signals that are reflected by a prism
reflector or the object under survey.
The modulation pattern in the returning signal is read and
interpreted by the computer in the total station. The distance
is thus determined by emitting and receiving multiple
frequencies and determining the integer number of
wavelength, to the target, for each frequency or by pulse laser
that computed by velocity of light by time.
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24. Functions Of Total Station
3-Angular measurement:
Most of the modern total stations have digital bar-codes on
rotating glass cylinder that are installed within the instrument.
Angle measurements is done through electro-optical scanning
of these digital bar-codes
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25. Functions Of Total Station
4- Topography - allows topography of a region to be
measured.
5-Traverse Adjustment - allows series of stations used as
traverse to be calculated for closure. The program can then
calculate the adjustments required in the stations to ensure
closure.
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26. Functions Of Total Station
6- Resection - calculates the
coordinates of an unknown or free
station by observing a number of
unknown stations from the unknown
point.
7-Building Face Survey - used to
survey details of a building including
details where the prism cannot be
placed.
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27. Functions Of Total Station
8- Remote Elevation - used to measure elevations
of points in which the target can’t be placed. (e.g..
Powerline heights, bridge heights).
The prism is placed directly
below the object and the slope
distance to the prism is
recorded along with the angle
up to the remote elevation.
Based on these measurements,
the remote elevation point can
be calculated.
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28. Functions Of Total Station
9 Setting out Coordinates - allows coordinates to be
placed in the field.
10Setting out Line
11-Set out Arc
12- Area calculation 28

29. Functions Of Total Station
13-Data processing:
The data recorded by the instrument may be downloaded
from the device to a computer and the application software in
turn generates a map of the survey area.