Abstract: Orthogonal gyroscopes, accelerometers, with odometer, are usually mounted inside the PIG for mapping by pipeline geometry PIG. The solution calculates the geographical coordinates of the pipeline track. An iterative Kalman algorithm was usually used to restrain the original data noise, but iteration termination conditions were difficult to judge. In this paper, because the initial segment of the pipeline and launch tube are straight, and PIG initial attitude is controllable and measurable, combined with the stationary base alignment effect evaluation, the filter performance can be determined and the de-noising process can be optimized, so that the initial alignment and subsequent pipeline geographical coordinates calculation accuracy has been improved significantly.