ISO 9849:2017

INTERNATIONAL ISO
STANDARD 9849
Third edition
2017-08
Optics and optical instruments —
Geodetic and surveying instruments
— Vocabulary
Optique et intruments d’optique — Instruments géodésiques et
d’observation — Vocabulaire
Reference number
ISO 9849:2017(E)
©
ISO 2017

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ISO 9849:2017(E)

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© ISO 2017, Published in Switzerland
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ISO 9849:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Types of geodetic instruments and related terms . 1
3.2 Parts of geodetic instruments . 7
Bibliography .18
Index .19
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ISO 9849:2017(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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constitute an endorsement.
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expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee
SC 6, Geodetic and surveying instruments.
This third edition cancels and replaces the second edition (ISO 9849:2000), which has been technically
revised.
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ISO 9849:2017(E)

Introduction
This document forms one of a series concerning geodetic and surveying instruments. It gives definitions
of terms which may be used in the drafting of other International Standards and national standards in
this field.
Only terms relating to geodetic and surveying instruments for geodetic work and their essential
parts are described in this document. It is intended for both the surveyor and the non-surveyor. Every
reader is requested to use only these terms in the future so that, with time, a standard and acceptable
terminology will come into common usage.
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INTERNATIONAL STANDARD ISO 9849:2017(E)
Optics and optical instruments — Geodetic and surveying
instruments — Vocabulary
1 Scope
This document defines terms relating to geodetic field instruments only, e.g. distance meters, levels,
theodolites and others, and their essential component parts which are normally used in terrestrial
measuring operations of ordnance survey, topographic survey, plane survey and engineering
survey. Therefore, terms concerning fields such as the following are not mentioned, for example,
photogrammetry, astronomy, hydrographic survey and industrial metrology.
Accessories which are not necessary for the functioning of the instruments are not dealt with. The
terms are arranged in English alphabetical order.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1 Types of geodetic instruments and related terms
3.1.1
alignment instrument
device used to aim at intermediate points and to a reference target at the end of an alignment
Note 1 to entry: The device is usually equipped with a powerful magnifying telescope (3.2.38).
3.1.1.1
alignment laser
line laser
pipe laser
alignment instrument (3.1.1) using a laser beam as reference line instead of an optical line of sight
3.1.2
barometer
instrument for measuring atmospheric pressure
Note 1 to entry: Barometers can be used for the atmospheric reduction of electronically measured distances or
as barometric altimeters (3.1.2.2).
3.1.2.1
aneroid barometer
barometer (3.1.2) in which atmospheric pressure is balanced by some elastic elements as a method that
does not involve liquid
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3.1.2.2
barometric altimeter
barometer (3.1.2) used for elevation measurement, in which case a read out is provided in meters
3.1.2.3
mercury barometer
barometer (3.1.2) in which atmospheric pressure is balanced by the mass of a column of mercury
3.1.2.4
electronic barometer
instrument for measuring atmospheric pressure by conversion of physical observation to electrical
signals
3.1.3
electro-optical distance meter
electronic distance meter
EDM
instrument for measuring distances between the instrument and a reflective target, using various
electro-optical techniques, visible light or infrared radiation as carrier waves
Note 1 to entry: The target can be a reflector (3.1.15) or any other surface.
Note 2 to entry: See also total station (3.1.20), hand-held laser distance meter (3.1.7), terrestrial laser scanner
(3.1.8) and laser tracker (3.1.9).
3.1.3.1
phase shift distance meter
electronic distance meter which is based on the comparison of two modulation signals, one is the
reference signal, the other the return signal from the reflective target
Note 1 to entry: The phase difference can be detected by various methods and is used to calculate the distance.
3.1.3.2
pulsed distance meter
time of flight distance meter
electro-optical distance meter which is based on measuring the time of flight between transmission
and reception of the same pulse
3.1.4
field-controller
device that controls surveying instruments (total station, GNSS receiver, terrestrial laser scanner and
digital level) by using on-board applications, recalls surveying data or other information and records
and analyses measurement data of the instruments
3.1.5
Global Navigation Satellite System
GNSS
system consisting of several satellites in different orbital planes, which allow absolute navigation
solutions as well as high precise (e.g. differential) positioning and broadcasting of time due to the global
coverage
Note 1 to entry: GNSS includes all operating Global Navigation Systems by Satellite.
EXAMPLE 1 Global Positioning System (GPS) or Navigational Satellite Timing and Ranging – Global Positioning
System (NAVSTAR-GPS) – US Department of Defence navigation system based on the constellation of usually
more than 24 satellites at an altitude of 20 200 km above earth’s surface.
EXAMPLE 2 GLObal’naya NAvigationnaya Sputnikovaya Sistema (GLONASS) – Russia’s Global Navigation
Satellite System based on the constellation of approximately 24 satellites at an altitude of 19 100 km above
earth’s surface.
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EXAMPLE 3 Galileo – Global Navigation Satellite System organized by EU and European Space Agency. The
system is planned to consist of 30 satellites at an altitude of 23 200 km above earth’s surface.
EXAMPLE 4 Beidou – Satellite Navigation System operated by China. Satellites in medium earth orbit
(22 000 km above earth’s surface) as well as in geosynchronous orbit (35 790 km above earth’s surface) are used,
where the latter include satellites in both geostationary orbit and in inclined geosynchronous orbit.
EXAMPLE 5 Quasi-Zenith Satellite System (QZSS) – Satellite Navigation System operated by Japan. The System
is compatible with GPS.
3.1.5.1
GNSS receiver
electronic device that receives and digitally processes the signals from GNSS satellites in order to
provide position, velocity and time (of the receiver)
3.1.5.2
differential GNSS
DGNSS
processing application within mobile GNSS receivers, using difference techniques of GNSS observations
and additional reference point or reference network GNSS observations
Note 1 to entry: In differential GNSS (DGNSS) applications, correction data and additional information from a
known reference station are used by mobile rovers, enabling them to improve position accuracy from the 15 m
nominal GNSS accuracy to about 10 cm and less.
3.1.5.3
differential GPS
DGPS
DGNSS application using only observations from the GPS (Navstar Satellite System) and additional
reference point or reference network GPS observations
3.1.5.4
real-time kinematic
RTK
real-time processing algorithm technique of mobile GNSS receivers using the carrier phase of GNSS
observations for a positioning of the mobile GNSS receiver within a reference network in a low cm-level
Note 1 to entry: In real-time kinematic (RTK) application, measurements of the phase of the signal’s carrier
wave are used to provide real-time corrections. By a data link from the reference station to the rover station, the
corrections are transmitted to enhance the precision of the position up to cm-level.
3.1.6
gravimeter
gravity meter
gravity instrument
instrument for measuring the absolute gravity or the differences in the value of gravity
3.1.7
hand-held laser distance meter
electro-optical distance meter (3.1.3) which is used and held usually with the hands
Note 1 to entry: Usually, reflectorless EDM techniques are used.
3.1.8
terrestrial laser scanner
TLS
ground-based instrument using a scanning technology by a laser beam to produce detailed 3D data
including intensity of complex structures and objects and geometries
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3.1.9
laser tracker
portable coordinate measuring instrument based on laser interferometry techniques that enables to
get high accuracy 3D data in real time by tracking a reflector (3.1.15) or corner cube (3.1.15.1)
3.1.10
level
instrument for measuring differences in height by establishing horizontal lines of sight, comprising as
main components a telescope (3.2.38) which can be rotated on a vertical axis (3.2.44) and a facility for
levelling the line of sight
Note 1 to entry: It can be additionally fitted with a horizontal circle (3.2.7) and/or a parallel plate micrometer
(3.2.23). The reticule has sometimes stadia hairs for optical distance measurement.
Note 2 to entry: See also spirit level (3.2.16) and tachymeter (3.1.17).
3.1.10.1
automatic level
compensator level
self-levelling level
pendulum level
level which makes use of a tilt compensator (3.2.39) that ensures that the line of sight is horizontal once
the operator has roughly levelled the instrument
3.1.10.2
digital level
level which electronically reads a sequence of code patterns on the levelling staff (3.1.11) by an
image sensor
Note 1 to entry: These instruments usually include data recording capability. The automation removes the
requirement for the operator to read a scale.
Note 2 to entry: The processing and the display of the results are taken by an integrated computer.
3.1.10.3
electronic level
inclinometer
tiltmeter
instrument which detects inclination or changes of inclination under the influence of gravity by the use
of electronic sensors
3.1.10.4
tilting level
manual level
level which provides a tilting screw to establish a levelled line of sight
3.1.11
levelling staff
levelling rod
level rod
straight bar with a scale on a flat face
Note 1 to entry: The levelling staff can be made of, for example, metal, glass fibre or wood.
Note 2 to entry: The levelling staff is used to measure the vertical distance between a base point and the
horizontal line of sight of a level (3.1.10).
3.1.11.1
digital levelling staff
bar code staff
levelling staff (3.1.11) for levelling with a digital level (3.1.10.2) having a specified code patterns on the
flat face
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3.1.11.2
invar levelling staff
precise levelling rod
invar rod
levelling staff (3.1.11) for precise levelling, having an invar strip with graduation lines or code patterns
(bar code)
−6
Note 1 to entry: Invar is a Fe-Ni alloy to ensure a low coefficient thermal expansion (<10 /°C).
3.1.12
optical plummet
instrument or device that realizes a visible line of sight in a vertical zenith or nadir direction
Note 1 to entry: The optical plummet can be levelled by liquid horizon, tubular levels or compensators.
Note 2 to entry: An optical plummet can also be a part of a geodetic instrument.
Note 3 to entry: It can be used for placing a mark on the ground or centring an instrument over a mark on the
ground (nadir plummet) as well as for centring an instrument under a point (zenith plummet).
3.1.12.1
laser plummet
optical plummet (3.1.12) which uses a laser beam as a visual plumb line
3.1.12.2
optical precise plummet
optical plummet (3.1.12) comprising a telescope with high magnification and precise devices (e.g.
bubbles, compensator) to precisely realize the vertical line of sight
3.1.13
optical square
pentaprism
device equipped with pentagonal prism for determination of orthogonal lines of sight
3.1.14
plane table
device used in surveying and related disciplines to provide a solid and level surface on which to make
field drawings, charts and maps
Note 1 to entry: As a sighting instrument, usually, an alidade is used on the plane table.
Note 2 to entry: See also 3.2.27 for a description for a plane table as a part.
3.1.15
reflector
device at the target which reflects the light beam to an electro-optical distance meter (3.1.3) or to a
tracker system
Note 1 to entry: These devices are, for example, glass prism reflectors, corner cube reflectors, acrylic reflectors,
reflecting sheets.
Note 2 to entry: Reflectors are usually provided on a pole having a centring device. A 360° reflector device has
multiple glass prisms which are measurable from any horizontal direction.
3.1.15.1
retroreflector
corner cube
device that reflects light back to the light source exactly along the same light direction
Note 1 to entry: These devices are, for example, glass prism reflectors, corner cube reflectors.
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3.1.15.2
reflecting tape
reflecting sheet
reflector (3.1.15) of plane sheet or tape comprised of tiny prisms made of a flexible material
3.1.16
rotating laser
laser level
rotary laser
instrument generating a plane by means of a rotating laser beam
3.1.17
tachymeter
tacheometer
instrument for measuring horizontal directions, vertical angles and distances
3.1.18
target
target plate
symmetrical figure, structure or reflector defining a point on the target to which observations are taken
Note 1 to entry: It is usually provided with some form of a forced-centring device (3.2.13).
3.1.19
theodolite
transit
optical instrument for measuring horizontal directions and vertical angles, whose main components
are the horizontal circle and the vertical circle inclusive reading systems, the telescope (3.2.38) and the
alidade (3.2.1) inclusive the horizontal and vertical rotation axes
Note 1 to entry: The telescope can be rotated around the horizontal axis (3.2.15) and vertical axis (3.2.44).
Note 2 to entry: A theodolite can also be used for optical distance measurement.
Note 3 to entry: A theodolite used in astronomical work is usually termed an astronomical theodolite or a transit
instrument.
3.1.19.1
compass theodolite
compass transit
theodolite (3.1.19) attached with a centrally mounted compass (3.2.6) for determining the magnetic
azimuth
3.1.19.2
electronic theodolite
theodolite (3.1.19) with microprocessor(s), display and memory for automatic reading, processing,
displaying and storing of measurement data
3.1.19.3
gyrotheodolite
gyro-azimuth theodolite
survey gyroscope
theodolite (3.1.19) with a north-seeking gyro attached for the determination of the geographic north
direction
Note 1 to entry: In general, both theodolite and gyro form one unit. Different observation methods allow to
determine the geodetic azimuth.
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3.1.19.4
suspension theodolite
theodolite (3.1.19) in a hanging position to carry out measurements in the region of nadir, prior used for
mining surveys
3.1.20
total station
electronic tachymeter
electronic tacheometer
tachymeter (3.1.17) with microprocessor(s), display and memory for opto-electronic distance
measurement, angle reading, processing, displaying and storing of measurement data
3.1.20.1
multistation
combines the functionality of a total station (3.1.20), terrestrial laser scanner (3.1.8) and of imaging in
one instrument
Note 1 to entry: A multistation (3.1.20.1) has often the possibility to attach or integrate a GNSS, wireless
transmission techniques and other devices used for surveying.
3.1.20.2
non-prism total station
reflectorless total station
total station with capability to measure the distance to almost any object without the need of a specific
reflector
3.1.20.3
gyro total station
total station with a north-seeking gyro attached for the determination of the geographic north direction
3.1.20.4
double-image tacheometer
tacheometer (3.1.17) with the optical wedge system included in the path of the rays in the telescope
(3.2.38)
Note 1 to entry: It divides the image of a horizontal staff into two horizontally displaced images. The size of the
displacement is the index of the distance reduced for the difference in height.
3.1.21
tripod
three-legged stand to which instruments or accessories can be attached and set up in a stable manner
on the ground
Note 1 to entry: The tripod consists of a head and three legs made of wood or metal, with metal tips. The legs are
either rigid or telescopic and connected with the tripod head by joints. The tribrach (3.2.41) is fixed on the head
of the tripod.
3.2 Parts of geodetic instruments
3.2.1
alidade
turning board
DEPRECATED: alhidade, alhidad, alidad
device that allows one to sight a distant object and uses the line of sight to perform a task, consisting
of an upper part (3.2.42) or turning part of a theodolite or total station with telescope (3.2.38) which
can be rotated around the standing axes (3.2.44) with or without vertical circle and an opto-electronic
distance-measuring device
Note 1 to entry: This task can be, for example, to draw a line on a plane table (3.1.14) in the direction of the object
or to measure the angle to the object from some reference point.
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3.2.2
base part
lower part
bottom part
centring flange
integrated group of parts of a theodolite (3.1.19) or the total station (3.1.20), supporting the limb (3.2.18)
and the upper part (3.2.42), and are firmly attached to the tribrach (3.2.41) during the measurement
Note 1 to entry: The base part consists essentially of the bearings for the vertical axis (3.2.44) and connecting
devices for the detachable tribrach.
3.2.3
base plate
lower part of the tribrach (3.2.41), connected by screws to the spring plate (3.2.36) and the foot screws
(3.2.12), which rest on this metal plate
3.2.4
circle drive
device for turning the horizontal and vertical circle of a theodolite (3.1.19) or total station (3.1.20)
[usually the telescope (3.2.38)] in relation of the fixed parts
3.2.5
clamp
device which enables rotating parts of the instrument to be clamped together when precisely sighting a
target, usually with clamps on the horizontal and vertical axis circles
Note 1 to entry: There are different types of clamps: central clamp, coaxial clamp and friction clamp (also called
friction brake).
Note 2 to entry: See also fine-motion device (3.2.10).
3.2.5.1
horizontal clamp
device for clamping the upper part (3.2.42) to the base part (3.2.2) of a theodolite (3.1.19) or total station
(3.1.20)
Note 1 to entry: See also horizontal fine-motion device (3.2.10.1).
3.2.5.2
repetition clamp
device of a theodolite (3.1.19) or a total station (3.1.20) for clamping the horizontal circle to the upper
part (3.2.42) in order to fix mechanically and temporarily a certain angle to the upper part
3.2.5.3
vertical clamp
device for clamping the horizontal axes (3.2.15) in order to fix mechanically and temporarily a certain
angle to the telescope (3.2.38) in respect to the vertical axis (3.2.44)
Note 1 to entry: See also vertical fine-motion device (3.2.10.2).
3.2.6
compass
device which can be mounted on a theodolite (3.1.19) or total station (3.1.20) in order to orient the
horizontal circle according to the direction of magnetic north
Note 1 to entry: Various types are full circle compass, line compass or case compass and tubular compass.
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3.2.7
circle
graduated circle
disc with a circular scale graduated in degrees or other code patterns which may be subdivided
Note 1 to entry: The disc is usually made of glass.
Note 2 to entry: The disc is sometimes graduated in gons.
Note 3 to entry: Electronic theodolites (3.1.19.2) have coded circular scales on discs which are scanned
electronically.
Note 4 to entry: The horizontal circle for measuring horizontal directions is mounted centrally on the vertical
axis (3.2.44) and securely attached to the base part (3.2.2) during measurement.
Note 5 to entry: The vertical circle for measuring vertical angles is fixed at right angles to and centrally on the
horizontal axis (3.2.15).
3.2.8
display
device which indicate the measured quantity or various information which is necessary for operation
Note 1 to entry: An electronic display is usually used in electro-optical distance meters (3.1.3), electronic
theodolites (3.1.19.2) or total station (3.1.20), digital level (3.1.10.2) and others, e.g. to show the instrument status,
current operations, results of measurements or calculations.
3.2.8.1
touch screen
finger-sensitive display to operate the instrument by finger or by pen in addition to or instead of keys
3.2.9
eyepiece
ocular
telescope (3.2.38) lens group which is nearest to the eye and with which the image formed by the
preceding elements is viewed
Note 1 to entry: It can be focused so that it produces a sharp image of the reticule (3.2.30) adapted to the
individual human eye of the observer.
3.2.9.1
prismatic diagonal eyepiece
prismatic eyepiece
eyepiece prisms
eyepiece (3.2.9) used in connection with a telescope (3.2.38) in order to make possible or facilitate
steep sights
3.2.10
fine-motion device
slow-motion device
device for rotating the clamped axis by controlled small smooth movements
Note 1 to entry: There are two special (combined) types of fine-motion: rough-fine-motion and endless fine-motion.
Note 2 to entry: See also clamp (3.2.5).
3.2.10.1
horizontal fine-motion device
device for fine motion of the upper part (3.2.42)
Note 1 to entry: See also horizontal clamp (3.2.5.1).
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3.2.10.2
vertical fine-motion device
device for the fine motion of the telescope (3.2.38) on the horizontal axis (3.2.15)
Note 1 to entry: See also vertical clamp (3.2.5.3).
3.2.11
focusing drive
focusing knob
focusing ring
device for focusing the image in the telescope (3.2.38), by means of which the focusing lens can be
moved in order to shift the image generated by the objective lens into the plane of the reticule (3.2.30)
Note 1 to entry: At image total stations, it is also used to get a sharp live video stream from the telescope camera.
3.2.12
foot screw
component part of the tribrach (3.2.41)
Note 1 to entry: Usually, 3 foot screws are used for levelling the tribrach.
3.2.13
forced-centring device
constrained-centring device
centring
device whereby instruments and accessories are interchangeable by means of simple manual operation
on tripods (3.1.21), tribrachs (3.2.41) or pillars without the centring being lost at a certain position
Note 1 to entry: Usually, the tribrach has the function of a forced centring device.
3.2.14
gyroscope
gyro
device for measuring and maintaining orientation in space
Note 1 to entry: Gyroscopes are based on various principles: mechanical or microelectromechanical systems
(MEMS) gyroscopes, laser or fibre optic gyroscopes or quantum gyroscope.
Note 2 to entry: A mechanical gyroscope contains a rotating body on an axis that can turn freely in any direction,
so that the body resists the action of an applied force and maintains the same orientation in space irrespective of
the movement of the surrounding structure.
3.2.14.1
gyrocompass
device to determine astronomic north (true north) by means of gyroscope (3.2.14)
Note 1 to entry: See also gyrotheodolite (3.1.19.3) and gyro total station (3.1.20.3).
3.2.15
horizontal axis
tilting axis
elevation axis
axis on which the telescope (3.2.38) rotates up and down when moved vertically
Note 1 to entry: The horizontal axis is arranged normal to the optical axes of the telescope.
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3.2.16
spirit level
level
bubble level
closed hollow vial which is partially filled with liquid, the remaining space containing air which finds
its way to the highest point in the vial
Note 1 to entry: It is designed to indicate whether a surface is horizontal (levelled) or to measure the tilt of the
surface against the horizon.
Note 2 to entry: Electronic level sensors measure the tilt automatically.
Note 3 to entry: The level is used for levelling instruments, instrument parts and/or accessories. The main types
are the circular level (3.2.16.1) and the tubular level (3.2.16.2).
Note 4 to entry: See also level (3.1.10).
3.2.16.1
circular level
bull’s eye level
box bubble
circular bubble
circular, flat-bottomed device with the liquid under a slightly convex glass face with a circle mark at
the centre
Note 1 to entry: It serves to level a surface in a
...