On accuracy specifications of electronic distance meter

The electronic distance meter (EDM) is an essential surveying tool. The principle of operation is the same among various EDM devices such as the stand alone EDM device, the theodolite mounted EDM unit and the coaxial design integrated with a total station. However, two interpretations exist for EDM accuracy specifications. This study investigates the meaning and cause of the two interpretations of identical accuracy specifications. Explanations from textbooks and manufacturers are reviewed. The procedures for deriving the value used in the accuracy specifications in practice are also detailed briefly. This research suggests that a unified interpretation of EDM accuracy specifications would be beneficial for EDM education and practice.