ISO 14253-5:2015规定了用于评估根据双方同意的测试方案得出的测试值的不确定性的概念和术语，并且相对于在GPS指示测量仪器的验证测试中获得的仪器指示。 注意测试值的不确定性（称为测试值不确定度）不与与使用该测量仪器测量工件的测量不确定度相混淆。前者仅涵盖在ISO 14253的这一部分中;有关后者的指导参见ISO/IEC指南98 - 3（GUM）和ISO 14253 - 2。 当指示测量仪器的测试包括几个测试值，一些相对于仪器指示和一些其他测量特性，ISO 14253的这一部分仅关注前者的不确定性。 ISO 14253的这一部分不提供确保测试协议的充分性的指导方针;相反，一旦给出了测试协议，它描述了如何评估随后的测试值不确定性

ISO 14253-5:2015 specifies concepts and terms for evaluating the uncertainties of the test values derived according to a test protocol agreed upon by the parties and relative to instrument indication(s), obtained in verification testing of GPS indicating measuring instruments. NOTE The uncertainty of the test values, referred to as test value uncertainty, is not to be confused with the measurement uncertainty associated with using that indicating measuring instrument to measure workpieces. The former only is covered in this part of ISO 14253; for guidance on the latter see the ISO/IEC Guide 98‑3 (GUM) and ISO 14253‑2. When a test of an indicating measuring instrument comprises several test values, some relative to the instrument indication and some to other metrological characteristics, this part of ISO 14253 is concerned with the uncertainty of the former only. This part of ISO 14253 does not provide guidelines to ensure the adequacy of a test protocol; rather, once a test protocol is given, it describes how to evaluate the consequent test value uncertainty.