The position error data of inertial navigation systems (INS) are analysed. The data used for the analyses are of B747 aircraft equipped with three INS units, namely, Carousel IV. The inertial present positions by the three INS display units were recorded by crew after the aircraft had arrived at the gate of destination airport. The distributions of position errors are investigated and several distribution models were fitted to empirical distributions. The results indicate that the distribution of radial error rates is well fitted by a Weibull model with the shape parameter of 1.416.
