ISO 17123-9:2018

Overview

ISO 17123-9:2018 - Optics and optical instruments - Field procedures for testing geodetic and surveying instruments - Part 9: Terrestrial laser scanners - specifies practical field procedures to determine and evaluate the precision (repeatability) of terrestrial laser scanners and their ancillary equipment for building, civil engineering and surveying measurements.

This standard is intended primarily as a field verification of an instrument’s suitability for an immediate task and to help satisfy requirements in other standards. It is not a comprehensive acceptance or full performance evaluation but is an early step in assessing measurement uncertainty of scanner-derived measurands.

Key topics and technical requirements

• Scope and purpose: Field procedures for in-situ testing of TLS (terrestrial laser scanners) to quantify repeatability and contribute to uncertainty budgets.
• Two test procedures:
  • Simplified test procedure - quicker checks for routine field verification (examples and calculation steps included).
  • Full test procedure - more comprehensive field testing with statistical evaluation (includes derivation of permitted deviations).
• Measurement outputs treated as observables: modern scanners produce coordinates as standard outputs; tests are performed on the same day.
• Instrument readiness: the scanner and ancillary equipment must be in known acceptable states of permanent adjustment (per manufacturer’s handbook); levelling is optional.
• Meteorological data: record environmental data during acquisition to enable atmospheric corrections where applicable.
• Uncertainty and statistics:
  • Focus on experimental standard deviation (precision) and construction of uncertainty budgets (Type A and Type B components).
  • Use of statistical tests and distributions (e.g., F-distribution, Chi-square) to judge instrument behaviour and permitted deviations.
• Documentation and examples: normative and informative annexes provide worked examples for both simplified and full procedures and guidance on Type B uncertainty budgets.

Practical applications and users

ISO 17123-9:2018 is used to:

• Verify the suitability of a terrestrial laser scanner for an immediate surveying, building or civil-engineering task.
• Provide input data for measurement uncertainty estimation and reporting in surveying deliverables.
• Support quality assurance in construction layout, deformation monitoring, as-built surveys and BIM capture workflows.

Typical users:

• Surveyors and geodetic engineers
• Construction QA/QC teams and site engineers
• Instrumentation specialists and calibration personnel
• Organizations preparing measurement uncertainty statements or complying with related standards

Related standards and references

• ISO 17123 series (Part 1: Theory)
• ISO/IEC Guide 98-3 (GUM: Guide to the expression of uncertainty in measurement)
• ISO 3534-1, ISO 4463-1, ISO 7077, ISO 7078, ISO 9849 - referenced for terms, statistics and measurement procedures

Keywords: ISO 17123-9:2018, terrestrial laser scanners, TLS field procedures, measurement uncertainty, repeatability, surveying standards, field verification, precision testing.