Availability of the Certain Value of Position Error in the Navigational Systems - Model Application

The distributions and parameters of the random variable (density functions, distribution functions, expected values, variances, moments etc.), which in navigation is represented by position error, are well defined. This approach is similar like in geodesy, where passing time hasn't any impact on statistical solution. Presented paper evaluates alternative approach to position error analyses, where the random values are: working and failures times of the system. Arbitrary accepted certain value of position error was assumed as a decision criterion of the system for working state definition. The general mathematical model of the availability of certain value of position error is presented and the special case - exponential distributions of lifetimes and failure times model - was also analysed. The model was adopted for positioning based on EGNOS system measurements and some results are present.