Annotation: To solve the navigation tasks (determination of the apparent accelerations and angular velocities and calculation of rocket orientation angles) in the rocket engineering, the data from the sensing elements (angular velocity sensors and accelerometers) is used. Accuracy of reference attitude determination of the rocket in the steady mode (at lift-off) has great influence on accuracy of the received navigation data during the flight. Gimballess inertial navigation system, built on the basis of inertial MEMS-sensors of Industry class (three angular velocity sensors and three accelerometers), is taken as the navigation device. In the classical version, the integration of data from angular velocity sensors and from accelerometers is the basis of gimballess inertial navigation system operation. It results in accumulation of errors when solving the navigation task (in particular due to the integration of data from angular velocity sensors). Taking it into consideration, the alternative method of rocket’s reference attitude determination during the pre-launch processing is offered. This method does not use mathematical operations of integration and is autonomous. Initial data, received from the gimballess inertial navigation system, is used as the output data. This data is used to determine the rocket’s reference attitude (orientation of object-centered coordinates in the geographical reference system) in the steady mode. Orientation angles are determined without the integration of data picked up from the angular velocity sensors. The comparative analysis to define the processing efficiency of the navigation device initial data was held during the determination of the rocket’s orientation angles in the steady mode, using the proposed method and Runge-Kutta method. The received results showed that accuracy of the reference attitude determination with the proposed method is higher. Thus, the proposed method will help reduce the errors in determination of the rocket’s reference attitude in the steady mode that in the future will improve the accuracy in determination of navigational parameters during the rocket’s flight.

Annotation: Contemporary trends in developing space-rocket hardware indicate the increased demand for light and ultra-light rockets. The first trend in developing the up-to-date light and ultra-light rocket hardware includes improving accuracy of cargo delivery to the specified area; the second trend covers the enhancement of energetic properties and the reduction of production and operational costs. Spinning about the longitudinal axis of symmetry may be one of the ways to improve the light and ultra-light rocket hardware in these trends. Spinning significantly increases stability of a moving object and partially evens out the negative impact of external and internal disturbing factors (skewness and eccentricities of propulsion system and control elements, wind). Refusal to use systems that provide stabilization about the longitudinal axis of symmetry leads to reduction in mass of the control system equipment, thus increasing energetic perfection of the rocket hardware. Hence, rotation of the rocket about the longitudinal axis may be caused by the spinning elements on purpose as well as by disturbing impacts in case of control failure in the roll channel. This article considers suggestions on algorithmic realization of light rocket control methods under conditions of rapid rotation about the longitudinal axis for each of the options mentioned above. This article offers control methods for the rocket, rotating about the longitudinal axis, that provide angular stabilization, improve the transient quality, and determine the angle of roll after program stop of rotation about the longitudinal axis.

Annotation: The paper deals with the options of solving the task of constructing an inertial navigation system in the conditions of considerable g-load and angular velocity in identified direction by method of setting the sensitive elements at some angle to the identified direction, which allows making measurements in it without loss of measurement quality in the other directions. The paper describes the technique of calculating the angle of sensitive elements setting to the identified direction. The scheme of constructing an inertial navigation system with incomplete set of sensitive elements is considered for the cases when in entire operation leg, rotation around the identified direction is executed. The analysis is given of measurement vector error due to incompleteness of the sensitive elements set.