CORRECTION METHOD OF STRAP DOWN INERTIAL NAVIGATION SYSTEM Russian patent published in 2018 - IPC G01C21/06 

FIELD: measuring equipment.

SUBSTANCE: method includes the complexation of signals, corresponding to the angular speed and the earth speed of the object with signals, corresponding to linear accelerations and transformed with regard to the parameters of the object's flight and the adaptive estimation of roll and pitch by means of the Kalman filter in which the gain coefficient changes, depending on the current values of the overload modules and the linear speed, as well as the angular speeds. Additionally the signal corresponding to the object longitudinal velocity, obtained from the air-signal system (ASS) as the function from the dynamic pressure, and the signal, corresponding to the longitudinal acceleration, obtained by differentiating and then smoothing of the speed signal from the ASS is used. Besides, Kalman filter coefficients are optimized by forming nine training sequences, for that purpose assign six filter coefficients to be adjusted, and the quality criterion in the form of the weighted mean square error (MSE) of the roll and pitch orientation, averaged over time and over the set of all nine training sequences. Optimisation of the algorithm coefficients is carried out in three stages. The first stage concludes in numerical minimization of the quality criterion and determination of the coefficients for flights in the calm atmosphere. The second stage concludes in numerical minimization of the quality criterion and determination of the coefficients for flights at turbulence conditions. The third stage defines the procedure, that satisfies the flights with the sufficient accuracy both in the calm atmosphere and in turbulence, by linear interpolation of the Kalman filter coefficients according to the results of the first and the second stages. The invention allows to use ARS and LAS sensors of medium and low accuracy, including micromechanical type, because errors are not accumulated due to continuous correction. The device doesn't require the initial alignment, it has the ability to self-align within several seconds and can be used in all known aircraft types.

EFFECT: accuracy increase of the correction method of strap down inertial navigation system according to the angles of roll and pitch.

3 dwg, 1 tbl