Strapdown Attitude Algorithms using Quaternion Transition Matrix and Random Inputs
Mohamed S. Ahmed, MSc (Eng)[1])
Danilo V. Ćuk, PhD (Eng)1)
The algorithms based on the transition matrix and quaternion concept were developed for determination of the vehicle’s attitude. They are constraint-preserving integrators and overcome the difficulty of some published algorithms which need first, second and third derivatives of vehicle’s angular rates. The effects of quantization of the gyroscopes impulse on the accuracy of the body attitude were studied and two types of estimators were proposed to estimate a vehicle’s attitude if the integrated angular rate is corrupted with uniformly distributed random noise. A series of numerical experiments were conducted to quantify the proposed estimators for coning motion with different motion’s frequencies. The proposed estimators are useful for the specified domain of the frequency of motion and sampling rate.
Key words: flight mechanics, navigation, navigational system, inertial guidance, spatial attitude, estimators, quaternion, estimation, numerical algorithm.