Overview
ISO 17123-1:2014 is part of the ISO 17123 series, developed by the International Organization for Standardization (ISO), focusing on optics and optical instruments. Part 1, titled "Theory," lays the foundation for evaluating and expressing measurement uncertainty in field procedures for testing geodetic and surveying instruments. This standard provides crucial guidance on uncertainty concepts, aligning with ISO/IEC Guide 98‑3, and is tailored for practical use in geodetic test measurements. By establishing unified, practical methods for expressing and quantifying uncertainties, ISO 17123-1:2014 supports the accuracy and reliability of geodetic and surveying equipment assessments in the field.
Key Topics
- Measurement Uncertainty: Defines measurement uncertainty as a non-negative parameter indicating the dispersion of quantity values attributed to a measurand, based on available information.
- Evaluation Methods: Differentiates between Type A (statistical analysis) and Type B (other means, e.g., manufacturer’s data, previous measurements, or experience) evaluations of measurement uncertainty.
- Uncertainty Budget: Introduces the concept of an uncertainty budget-a statement of measurement uncertainty components and their calculation and combination.
- Propagation of Uncertainty: Explains the law of propagation of uncertainty and how combined standard uncertainty is determined.
- Reporting and Statistical Tests: Outlines procedures for reporting uncertainty results and applying statistical tests to evaluate the precision and reliability of field measurement outcomes.
- Key Metrological Terms: Provides comprehensive definitions for key terms such as accuracy, precision, repeatability, reproducibility, systematic error, random error, and coverage interval.
Applications
ISO 17123-1:2014 is valuable for:
- Field Verification: Ensuring geodetic and surveying instruments meet task-specific accuracy requirements before deployment on construction or land survey projects.
- Instrument Calibration: Supporting calibration laboratories and metrology services by clarifying how to quantify and express uncertainty during instrument testing.
- Quality Assurance: Assisting organizations in developing internal quality protocols for measurement reliability and conformity with international best practices.
- Education and Training: Serving as a reference for professionals and trainees in geodesy, surveying, metrology, and related fields to adopt a uniform approach to uncertainty evaluation.
- Supporting Subsequent Standards: Acting as the theoretical basis for the practical field test procedures described in ISO 17123 parts 2 through 8 (covering instruments like levels, theodolites, EDMs, total stations, lasers, optical plumbing instruments, and GNSS systems).
Related Standards
Several standards complement ISO 17123-1:2014 by providing specific field procedures for various geodetic and optical instruments:
- ISO 17123-2: Field procedures for testing levels.
- ISO 17123-3: Field procedures for testing theodolites.
- ISO 17123-4: Field procedures for electro-optical distance meters (EDM) using reflectors.
- ISO 17123-5: Field procedures for total stations.
- ISO 17123-6: Field procedures for rotating lasers.
- ISO 17123-7: Field procedures for optical plumbing instruments.
- ISO 17123-8: Field procedures for GNSS field measurement systems in real-time kinematic (RTK) applications.
- ISO/IEC Guide 98-3: Guide to the Expression of Uncertainty in Measurement (GUM).
- ISO/IEC Guide 99: International vocabulary of metrology-basic and general concepts and associated terms (VIM).
Practical Value
By implementing the guidelines of ISO 17123-1:2014, organizations and professionals involved in field surveying and geodetic measurements can:
- Achieve standardized, credible measurement results.
- Clearly communicate the confidence and limitations of instrument results.
- Comply with international standards, improving the quality and acceptance of measurement data across projects.
- Enhance traceability and transparency in reporting field testing outcomes, increasing trust in the instruments and processes used for surveying, construction, monitoring, and mapping tasks.