ISO 14253-5:2015规定了评估试验值不确定度的概念和术语，这些不确定度是根据双方商定的试验协议得出的，与GPS指示测量仪器验证试验中获得的仪器指示有关。 注:试验值的不确定度（称为试验值不确定度）不得与使用指示测量仪器测量工件的测量不确定度相混淆。ISO 14253本部分仅涉及前者；关于后者的指导，请参见ISO/IEC指南98-3（GUM）和ISO 14253-2。 当指示测量仪器的测试包括多个测试值时，一些与仪器指示有关，一些与其他计量特性有关，ISO 14253的本部分仅涉及前者的不确定度。 ISO 14253的本部分未提供确保试验方案充分性的指南；相反，一旦给出测试协议，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.