Tuning of Coning Algorithms to Gyro Data Frequency Response Characteristics

Abstract

Substantial efforts have gone into the development of sophisticated algorithms that reduce system drift errors in the presence of coning motion. Present-day algorithms form high-order coning correction terms using multiple incremental angle outputs from the gyros. These algorithms assume a  at transfer function for the processing of the incremental angle outputs and are structured to yield very high-order responses. However, these algorithms do not address the issue of nonideal gyro frequency response or of Ž ltered gyro data. Many gyros exhibit complex frequency responses and violate the assumptionsused in deriving the previously developed coning algorithms.The mismatchbetween the assumedandactual frequency response of the gyrodata leads to degradationof performance in a coning environment as well as ampliŽ cation of pseudoconing errors. A method of deriving algorithms that are tailoredto the frequency response of the particular typeof gyrosused is presented. Thesealgorithmscanbedesigned to arbitrarily high order and can also supply an extremely sharp high-frequency cutoff to minimize pseudo-coning errors. Additionally, this method can be used to design coning algorithms that are tuned to deliberately Ž ltered gyro data. The technique developed equally applies to mechanical, Ž ber-optic, and other types of gyros.