ISO 17123-6:2003

INTERNATIONAL ISO
STANDARD 17123-6
First edition
2003-03-01


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 17123-6:2003(E)
©
ISO 2003

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ISO 17123-6:2003(E)
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ISO 17123-6:2003(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 General. 2
5 Simplified test procedure. 4
6 Full test procedure. 6
Annex A (informative) Example of the simplified test procedure. 14
Annex B (informative) Example of the full test procedure . 17


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ISO 17123-6:2003(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 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 17123-6 was prepared by Technical Committee ISO/TC 172, Optics and optical instruments,
Subcommittee SC 6, Geodetic and surveying instruments.
This first edition of ISO 17123-6 cancels and replaces ISO 8322-6:1991, which has been technically revised.
ISO 17123 consists of the following parts, under the general title Optics and optical instruments — Field
procedures for testing geodetic and surveying instruments:
 Part 1: Theory
 Part 2: Levels
 Part 3: Theodolites
 Part 4: Electro-optical distance meters (EDM instruments)
 Part 5: Electronic tacheometers
 Part 6: Rotating lasers
 Part 7: Optical plumbing instruments

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INTERNATIONAL STANDARD ISO 17123-6:2003(E)

Optics and optical instruments — Field procedures for testing
geodetic and surveying instruments —
Part 6:
Rotating lasers
1 Scope
This part of ISO 17123 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 part of ISO 17123 can be thought of 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 factors. These include among others: repeatability, reproducibility (between day
repeatability) and a thorough assessment of all possible error sources, as prescribed by the ISO Guide to the
expression of uncertainty in measurement (GUM).
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 referenced documents are indispensable for the application 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: Probability and general statistical terms
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, Building construction — Procedures for setting out, measurement and surveying — Vocabulary and
guidance notes
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
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ISO 17123-6:2003(E)
GUM, Guide to the expression of uncertainty in measurement BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML
VIM, International vocabulary of basic and general terms in metrology BIPM, IEC, IFCC, ISO, IUPAC, IUPAP,
OIML
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, GUM and VIM apply.
4 General
4.1 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 where the tasks are to be undertaken. Note should
also be taken of the actual weather conditions at the time of measurement and the type of surface above
which the measurements are made. 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).
Tests performed in laboratories would provide results which are almost unaffected by atmospheric influences,
but the costs for such tests are very high, and therefore they are not practicable for most users. In addition,
laboratory tests yield precisions much higher than those that can be obtained under field conditions.
This part of ISO 17123 describes two different field procedures as given in Clauses 5 and 6. The operator
shall choose the procedure which is most relevant to the project’s particular requirements.
4.2 Procedure 1: Simplified test procedure
The simplified test procedure provides an estimate as to whether the precision of a given rotating-laser
equipment is within the specified permitted deviation, according to ISO 4463-1.
This test procedure is normally intended for checking the precision 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 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 6.
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 6.
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
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ISO 17123-6:2003(E)
have to be observed by rotating the laser plane by 180°. The mean value of repeated readings in both
positions will provide the height difference which is accepted as true.
4.3 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 and b ,
1 2
22
of the deviation of the rotating axis from the true vertical, bb=+b , of the rotating laser (see Figure 1).
12

a) Horizontal plane b) Vertical plane through x′
Key
1 inclined plane
2 cone axis
3 inclined cone
Figure 1 — Deflective deviations a and b (see Figure 5)
The recommended sight lengths are 40 m. Sight lengths greater than 40 m may be adopted for this precision-
in-use test where the project specification may dictate, or to determine the range of the measure of precision
of a rotating laser at respective distances.
The test procedure given in Clause 6 of this part of ISO 17123 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 distance of 40 m:
s
ISO-ROLAS
Further, this procedure may be used to determine:
 the measure of precision in use of rotating lasers by a single survey team with a single instrument and its
ancillary equipment at a given time;
 the measure of precision in use of a single instrument over time and differing environmental conditions;
 the measure of precision in use of each of several rotating lasers in order to enable a comparison of their
respective achievable precisions to be obtained under similar field conditions.
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ISO 17123-6:2003(E)
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.
5 Simplified test procedure
5.1 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 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 regularly as possible (see Figure 2).

Key
S instrument station
1, 2, 3, 4, 5, 6 fixed target points
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, reliably fixed during the test
measurements, including repeat measurements.
The height differences between the six fixed points, 1, 2, 3, 4, 5 and 6, shall be determined using an optical
level of known high accuracy as described in Clause 4.
The following five height differences are known:
d
2,1
d
3,2
d
4,3
d
5,4
d
6,5
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ISO 17123-6:2003(E)
5.2 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 assure 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 of measurements
number, jj(1=,.,5).
Six separate readings, x , ., x , on the scale of the levelling staff shall be carried out to each fixed target
j,1 j,6
point, 1, ., 6. Between two sets of readings the instrument has to 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.
5.3 Calculation
The evaluation of the readings is based on the following differences:
d = x − x
j,2,1 j,2 j,1
d = x − x
j,3,2 j,3 j,2
d = x − x j = 1, ., 5 (1)
j,4,3 j,4 j,3
d = x − x
j,5,4 j,5 j,4
d = x − x
j,6,5 j,6 j,5
where
j is the number of the set of measurements to the fixed target points, 1, ., 6;
rd=−d
jj,2,1 2,1 ,2,1
rd=−d
jj,3,2 3,2 ,3,2
rd=−d j = 1, ., 5 (2)
jj,4,3 4,3 ,4,3
rd=−d
jj,5,4 5,4 ,5,4
rd=−d
jj,6,5 6,5 ,6,5
where r (t =2, ., 6 is the number of the fixed target points) is the residual of the height difference d .
j,t,t−1 j,t,t−1
5 5 555 56
2 2 2 222 2
∑r=r+r+++rrr= r (3)
j,2,1 j,3,2 jjj,4,3 ,5,4 ,6,5 j,t,t−1
∑ ∑ ∑∑∑ ∑∑
j=1 j=1 jjj===111 j=1t=2
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ISO 17123-6:2003(E)
where
2
∑ r is the sum of the squares of all 25 residuals;
ν=×5(6−1)=25 is the corresponding number of degrees of freedom.
2
∑ r
s = (4)
v
where s is the experimental standard deviation of a single measured height difference, d , between two
j,t,t−1
points of the test field and represents in this International Standard a measure of precision. This value
includes systematic and random errors.
6 Full test procedure
6.1 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 approximately 40 m apart. 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 distances from the
instrument’s positions to the levelling points shall be in accordance with Figure 3. The position S1 shall be
chosen equidistant between the levelling points, A and B (40/2 = 20 m).
Dimensions in metres

Figure 3 — Configuration of the test line for the full test procedure
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ISO 17123-6:2003(E)
6.2 Measurements
Before commencing the measurements, the instrument shall be adjusted as specified by the manufacturer.
For the full test procedure, m = 4 series of measurements, (i), shall be taken. Each of which requires the
instrumen
...