Research on Specification Uncertainty in the Next Generation GPS

Abstract

The next generation GPS standard system is based on operation/operator. One of the most important motivations of the next generation GPS is to reduce specification uncertainty. This paper analyzes the origination of specification uncertainty and the relationship between specification uncertainty and other two important uncertainties in the next generation GPS, correlation uncertainty and measurement. And then the procedure for management of Specification uncertainty is proposed in the paper. Finally, a method on evaluation of specification uncertainty and the general formula for this method is proposed. The embodied formula for estimation of specification uncertainty on the diameter example is deduced in the paper.

Tolerancing: Managing uncertainty from conceptual design to final product

“…-The specification uncertainty characterizes the ambiguity in the specification expression. It is caused by poor definitions in standards and other requirement documents [200]. -The measurement uncertainty is considered by the metrologists and well described in GUM.…”

Compliance uncertainty of diameter characteristic in the next-generation geometrical product specifications and verification

“…Equation ( 4) means that each operation is related to some influential factors, i.e., parameters, nested indices, etc. If the characteristic char(k) is a relational one that has datum features, the process for each datum feature is similar to the specified feature itself, that is equations ( 5)-( 7) [11]. The whole process is demonstrated in figure 2, in which I expresses the specification that satisfies the function of the part, II is the ideal metrology process for the specification, III is the parameters and nested indices included in the metrology process and IV is the database support for their implementation.…”

“…Ignoring the eccentricity of the instrument center and the part center [13], the constraint that should be satisfied among the centre point and R GG in equation ( 10) and actual sampling points can be written as equation (11) according to the principle of the least squares method:…”