Uncertainty of Angle Measurements Made with Theodolites: What ISO 17123-3 and Does Not Mean

Abstract

Uncertainty of Angle Measurements Made with Theodolites: What ISO 17123-3 Does and Does Not Mean. The ISO 17123-3 standard is in wide use in the surveying industry. It’s used to allow customers and manufacturers to compare instruments such as theodolites, transits and total stations, according to a consensus standard with international credibility. The result of the ISO 17123-3 test is also often used in manufacturer’s spec sheets as the “Angle Accuracy” for the instruments. This however, can be easily misinterpreted as the “uncertainty of the angle measurement made with the instrument.” This is not the intent of the standard, and making this assumption will usually cause one to underestimate the measurement uncertainty.