ThêoH Bias-removal Method

Abstract

A version of Theol variance, called TheoBR variance (BR for "bias-removed" relative to the Allan variance), is constructed. This relative bias correction is applied over a range of the longest recommended Allan r values for a given data run. TheoH deviation ('H' to indicate a hybrid combination of TheoBR, and Allan deviations) is the Allan deviation in short term and switches to the TheoBR, deviation in long term. In the presence of non-integer-power-law and mixed noise types, the approach is as effective and less cumbersome than past approaches, and requires little, if any, a priori knowledge or human judgment of data being analyzed. The substantially gained properties of Theol at large r, to 50 % beyond the longest possible r using the Allan deviation alone, can be obtained without Allan bias. Long-term frequency stability can be obtained in essentially one-third less time. For example, a two-month stability can be obtained with three months of data, rather than the four months of data that are usually required for such a point