ISO 17123-6:2022

INTERNATIONAL ISO
STANDARD 17123-6
Third edition
2022-05
Optics and optical instruments —
Field procedures for testing geodetic
and surveying instruments —
Part 6:
Rotating lasers
Optique et instruments d'optique — Méthodes d'essai sur site des
instruments géodésiques et d'observation —
Partie 6: Lasers rotatifs
Reference number
© ISO 2022
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms.2
4.1 Symbols . 2
4.2 Abbreviations . 3
5 General . 3
5.1 Requirements . 3
5.2 Procedure 1: simplified test procedure . 3
5.3 Procedure 2: full test procedure. 4
6 Simplified test procedure . 5
6.1 Configuration of the test field . 5
6.2 Measurements . . 6
6.3 Calculation . 7
7 Full test procedure .8
7.1 Configuration of the test line . 8
7.2 Measurements . 8
7.3 Calculation . 9
7.4 Statistical test . 13
7.4.1 General .13
7.4.2 Question a) . 14
7.4.3 Question b) .15
7.4.4 Question c) . 15
7.4.5 Question d) .15
8 Influence quantities and combined standard uncertainty evaluation (Type A and
Type B) .16
Annex A (informative) Example of the simplified test procedure .17
Annex B (informative) Example of the full test procedure .20
Annex C (informative) Example for the calculation of an uncertainty budget .25
Bibliography .28
iii
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
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
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
www.iso.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 17123-6:2012), which has been
technically revised.
The main changes are as follows:
— more flexible configuration of the test line and updating of the mathematical model;
— harmonization of terminology and symbols;
— correction of errors.
A list of all parts in the ISO 17123 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document specifies field procedures for adoption when determining and evaluating the uncertainty
of measurement results obtained by geodetic instruments and their ancillary equipment, when used in
building and surveying measuring tasks. Primarily, these tests are intended to be field verifications
of suitability of a particular instrument for the immediate task. They are not proposed as tests for
acceptance or performance evaluations that are more comprehensive in nature.
The definition and concept of uncertainty as a quantitative attribute to the final result of measurement
was developed mainly in the last two decades, even though error analysis has already long been a part
of all measurement sciences. After several stages, the CIPM (Comité International des Poids et Mesures)
referred the task of developing a detailed guide to ISO. Under the responsibility of the ISO Technical
Advisory Group on Metrology (TAG 4), and in conjunction with six worldwide metrology organizations,
a guidance document on the expression of measurement uncertainty was compiled with the objective
of providing rules for use within standardization, calibration, laboratory, accreditation and metrology
services. ISO/IEC Guide 98-3 was first published as the Guide to the Expression of Uncertainty in
Measurement (GUM) in 1995.
With the introduction of uncertainty in measurement in ISO 17123 (all parts), it is intended to finally
provide a uniform, quantitative expression of measurement uncertainty in geodetic metrology with the
aim of meeting the requirements of customers.
ISO 17123 (all parts) provides not only a means of evaluating the precision (experimental standard
deviation) of an instrument, but also a tool for defining an uncertainty budget, which allows for the
summation of all uncertainty components, whether they are random or systematic, to a representative
measure of accuracy, i.e. the combined standard uncertainty.
ISO 17123 (all parts) therefore provides, for each instrument investigated by the procedures, a proposal
for additional, typical influence quantities, which can be expected during practical use. The customer
can estimate, for a specific application, the relevant standard uncertainty components in order to derive
and state the uncertainty of the measuring result.
v
INTERNATIONAL STANDARD ISO 17123-6:2022(E)
Optics and optical instruments — Field procedures for
testing geodetic and surveying instruments —
Part 6:
Rotating lasers
1 Scope
This document specifies field procedures to be adopted when determining and evaluating the precision
(repeatability) of rotating lasers and their ancillary equipment when used in building and surveying
measurements for levelling tasks. Primarily, these tests are intended to be field verifications of the
suitability of a particular instrument for the immediate task at hand and to satisfy the requirements
of other standards. They are not proposed as tests for acceptance or performance evaluations that are
more comprehensive in nature.
This document can be considered as one of the first steps in the process of evaluating the uncertainty
of a measurement (more specifically a measurand). The uncertainty of a result of a measurement is
dependent on a number of parameters. Therefore this document differentiates between different
measures of accuracy and objectives in testing, like repeatability and reproducibility (between-day
repeatability), and of course gives a thorough assessment of all possible error sources, as prescribed by
ISO/IEC Guide 98-3 and ISO 17123-1.
These field procedures have been developed specifically for in situ applications without the need for
special ancillary equipment and are purposefully designed to minimize atmospheric influences.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in
probability
ISO 4463-1, Measurement methods for building — Setting-out and measurement — Part 1: Planning and
organization, measuring procedures, acceptance criteria
ISO 7077, Measuring methods for building — General principles and procedures for the verification of
dimensional compliance
ISO 7078, Buildings and civil engineering works — Procedures for setting out, measurement and surveying
— Vocabulary
ISO 9849, Optics and optical instruments — Geodetic and surveying instruments — Vocabulary
ISO 17123-1, Optics and optical instruments — Field procedures for testing geodetic and surveying
instruments — Part 1: Theory
ISO 17123-2, Optics and optical instruments — Field procedures for testing geodetic and surveying
instruments — Part 2: Levels
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 4463-1, ISO 7077,
ISO 7078, ISO 9849, ISO 17123-1, ISO 17123-2, ISO/IEC Guide 98-3 and ISO/IEC Guide 99 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols and abbreviated terms
4.1 Symbols
Symbol Quantity Unit
A design matrix —
a deflective deviation m
b deviation of the rotating axis m
D horizontal distance m
mean horizontal distance m
D
 height difference between target points m
d
vector of mean height difference of target points m
d
vector of height differences of target points m

d
h height difference of levelling staff B and A m
F F (Fisher) distribution —
f number of target point —
i series of measurement —
j set of measurement —
n set of readings —
P weight matrix of the observations —
p single weight factor —
Q Q matrix is the inverse of the weight matrix P —
r residual vector of the height differences m
r residual m
 experimental standard deviation m
ss,
t t-distribution —
u standard uncertainty m
x measured reading at levelling staff m
x observation vector of height differences m

y vector of unknown parameters m
mean vector of unknown parameters m
y
ν degrees of freedom —
α significance level %
σ theoretical standard deviation m
Symbol Quantity Unit
2 chi-squared distribution —
χ
Ω sum of residual squares m
4.2 Abbreviations
Abbreviation Description
A levelling point A
Ang Angle
B levelling point B
ISO-ROLAS ISO specific for rotation lasers
ISO International Organization for Standardization
S instrument station
x, y, z cartesian coordinate
5 General
5.1 Requirements
Before commencing surveying, it is important that the operator investigates that the precision in use of
the measuring equipment is appropriate to the intended measuring task.
The rotating laser and its ancillary equipment shall be in known and acceptable states of permanent
adjustment according to the methods specified in the manufacturer’s handbook, and used with tripods
and levelling staffs as recommended by the manufacturer.
The results of these tests are influenced by meteorological conditions, especially by the temperature
gradient. An overcast sky and low wind speed guarantee the most favourable weather conditions.
The particular conditions to be taken into account may vary depending on the location where the
tasks are to be undertaken. Note should also be taken of the actual weather conditions at the time of
measurements and the type of surface above which the measurements are performed. The conditions
chosen for the tests should match those expected when the intended measuring task is actually carried
out (see ISO 7077 and ISO 7078).
This document describes two different field procedures as given in Clauses 6 and 7. The operator shall
choose the procedure which is most relevant to the project’s particular requirements.
5.2 Procedure 1: simplified test procedure
The simplified test procedure provides an estimate as to whether the precision of a given item of
rotating-laser equipment is within the specified permitted deviation, according to ISO 4463-1.
This test procedure is normally intended for checking the precision (see ISO/IEC Guide 99:2007, 2.15) of
a rotating laser to be used for area levelling applications, for tasks where measurements with unequal
site lengths are common practice, e.g. building construction sites.
The simplified test procedure is based on a limited number of measurements. Therefore, a significant
standard deviation and the standard uncertainty (Type A), respectively, cannot be obtained. If a more
precise assessment of the rotating laser under field conditions is required, it is recommended to adopt
the more rigorous full test procedure as given in Clause 7.
This test procedure relies on having a test field with height differences which are accepted as true
values. If such a test field is not available, it is necessary to determine the unknown height differences
(see Figures 1 and 2), using an optical level of accuracy (see ISO 17123-2) higher than the rotating
laser required for the measuring task. If, however, a test field with known height differences cannot be
established, it will be necessary to apply the full test procedure as given in Clause 7.
If no levelling instrument is available, the rotating laser to be tested can be used to determine the true
values by measuring height differences between all points with central setups. At each setup, two
height differences have to be observed by rotating the laser plane by 180°. The mean value of repeated
readings in both positions will provide the height differences which are accepted as true.
5.3 Procedure 2: full test procedure
The full test procedure shall be adopted to determine the best achievable measure of precision of a
particular rotating laser and its ancillary equipment under field conditions, by a single survey team.
Further, this test procedure serves to determine the deflective deviation, a, and both components, b
2 2
and b , of the deviation of the rotating axis from the true vertical, bb=+ b of the rotating laser
2 1 2
(see Figure 1).
a)  Horizontal plane (top view) b) Vertical plane through x' (side view)
Key
1 inclined plane
2 cone axis
3 inclined cone
a
See Figure 5 also.
Figure 1 — Deflective deviations a and b
The recommended measuring distances within the test field (see Figure 3) are 40 m. Sight lengths
greater than 40 m may be adopted for this precision-in-use test only, where the project specification
may dictate, or where it is determining the range of the measure of precision of a rotating laser at
respective distances.
The test procedure given in Clause 6 of this document is intended for determining the measure of
precision in use of a particular rotating laser. This measure of precision in use is expressed in terms
of the experimental standard deviation, s, of a height difference between the instrument level and
a levelling staff (reading at the staff) at a certain distance. This experimental standard deviation
corresponds to the standard uncertainty of Type A [see Formula (1)]:
su:= (1)
ISO-ROLAS ISO-ROLAS
Further, this procedure may be used to determine the standard uncertainty as a measure of precision
in use of
— a single rotating laser and its ancillary equipment by a single survey team at a given time,
— a single rotating laser over time and differing environmental conditions, and
— several rotating lasers in order to enable a comparison of their respective achievable precisions to
be obtained under similar field conditions.
Statistical tests should be applied to determine whether the experimental standard deviation, s,
obtained belongs to the population of the instrumentation's theoretical standard deviation, 𝜎, whether
two tested samples belong to the same population, whether the deflective deviation, a, is equal to zero,
and whether the deviation, b, of the rotating axis from the true vertical of the rotating laser is equal to
zero.
6 Simplified test procedure
6.1 Configuration of the test field
To keep the influence of refraction as small as possible, a reasonably horizontal test area shall be
chosen. Six fixed target points, 1, 2, 3, 4, 5 and 6, shall be used to cover each horizontal quadrant at least
with one target and shall be set up in approximately the same horizontal plane at different distances,
between 10 m and 60 m apart from the instrument station S. The directions from the instrument to the
six fixed points shall be spread over the horizon as equally as possible (see Figure 2).
Key
S instrument station
1, 2, 3, 4, 5, 6 fixed target points (f)
Figure 2 — Configuration of the test field for the simplified test procedure
To ensure reliable results, the target points shall be marked in a stable manner and reliably fixed during
the test measurements, including repeat measurements.
The height differences between the six fixed points, 1 to 6, shall be determined using an optical level of
known high accuracy as described in Clause 5.
The following five height differences between the 6 target points are known and calculated with
Formula (2):

 
d
21,
 

d = 
 
(2)
 
  
d
ff, −1
 
f =26,,…
6.2 Measurements
The instrument shall be set up in a stable manner above point S. Before commencing the measurements,
the laser beam shall become steady. To ensure that the laser plane of the instrument remains unchanged
during the whole measuring cycle, a fixed target shall be observed before and after each set, j, of
measurements, ( j = 1,…,5).
Once the six target points are marked and reliably fixed, the six horizontal distances D between
f
instrument station and target points shall be measured, e.g. by using a tape measure or laser distance
meter.
Six separate readings, x to x , on the scale of the levelling staff shall be carried out to each fixed target
j,1 j,6
point, 1, 2, 3, 4, 5 and 6. Between two sets of readings the instrument shall be lifted, turned clockwise
approximately 70°, placed in a slightly different position and relevelled. The time between any two sets
of readings shall be at least 10 min.
Each reading shall be taken in a precise mode according to the recommendations of the manufacturer.
Detection of height differences should be done by using a laser receiver that is typically part of the
rotating laser set. This laser receiver should be set to the highest available sensitivity.
6.3 Calculation
The mean horizontal distance, D , between instrument station and target points of the test configuration
are calculated with Formula (3):
DD=
∑ f
(3)
f=1
f =16,,
The evaluation of the readings, x , for each set, j, is based on the differences calculated with Formula (4):
f

 d   xx− 
j,,21 jj,,21
   

d =  = −
   
j
   
 
   
d dx−
jf,,f −−1 jf,,jf 1
   
j =15,,… (4)
f =26,,…

Calculating d , the mean of the differences, d , the residual vector of the height differences in set, j, is
j
obtained by Formula (5):

rd=−d
jj
(5)
j=15,,…
The sum of the residual of the height differences in set j is defined as given in Formula (6):
T
Ω =rr (6)
j j j
Finally, the sum of the residual squares of all five sets yields is calculated with Formula (7):
ΩΩ= (7)
∑ j
j=1
The experimental standard deviation, s, is calculated with Formula (8):
Ω
su== (8)
ISO
ν
and where ν is the corresponding number of degree of freedom as calculated according to Formula (9):
ν =×56()−12= 5 (9)

and u the standard uncertainty (Type A) of a single measured height difference, d , between
ISO jf,,f−1
two points of the test field. This represents in this document a measure of precision relative to the
standard uncertainty of a Type A evaluation. This value includes systematic and random errors.
The experimental standard deviation s is expressed in the unit of length and refers to the specific size of
the configured test field. The transformation in a more comparable angular unit yields to Formula (10):
s
−1 
s =tan (10)
 
Ang
D 
A calculation example of the simplified test procedure is given in Annex A.
7 Full test procedure
7.1 Configuration of the test line
To keep the influence of refraction as small as possible, a reasonably horizontal test area shall be
chosen. The ground shall be compact and the surface shall be uniform; roads covered with asphalt or
concrete shall be avoided. If there is direct sunlight, the instrument and the levelling staffs shall be
shaded, for example by an umbrella.
Two levelling points, A and B, shall be set up apart from each other in a distance which is typical for
the working task and within the manufacturer’s specification, e.g. 40 m. To ensure reliable results, the
levelling staffs shall be set up in stable positions, reliably fixed during the test measurements, including
any repeat measurements. The instrument shall be placed at the positions S1, S2 and S3. The distance
from the instrument’s position S2 and S3 to the nearest levelling point shall be between 1/4 and 1/2 of
distance A-B. The position S1 shall be chosen equidistant between the levelling points A and B. See a
configuration example of using 40 m as distance, D , in Figure 3.
AB
Distances in metres
Figure 3 — Example of a configuration of the test line for the full test procedure
7.2 Measurements
Before starting measurements, the instrument shall be adjusted according to the ma
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