Recovery of Spacecraft motion by Results of the Telemetry measurements

Mikhail V.Levskii

The Research Institute of Space Systems - affiliate State Research and Production Space Centre of M.V.Khrunichev's name,

Tikhonravov street, 36, Jubilejny, Moscow region, 141080, Russia

 

Doubtlessly, one of the major problems arising during flight tests and nominal exploitation of modern spacecraft, still has comprehensive improvement of onboard systems with the purpose of their further modification, including perfecting of control algorithms by motion. This present article decide the problem of recovery under the data of distance measurements of a true angular motion of bulky spacecraft (on an example of an international space orbital station "Alpha" (ISS)) at fulfilment by it of spatial turns and definition of principal numerical characteristics of this motion.

For achievement of an object in view first of all it is necessary to select model depicting computational (or nominal) behaviour of parameters, describing motion of space vehicle concerning a center of the spacecraft mass. For this purpose the method of teaching models was used, as one of the most simple and at the same time most floppy and general purpose methods of identification. As an instrument parameters of an attitude the projections of the vector of absolute angular velocity on an axes of spacecraft-bound coordinate system were adopted.

The fixed assets of mathematical processing and analysis of the readings of distance measurements about motion of a space station (in its two configurations) in a mode of spatial turn are below briefly described. Then the in-depth enough results of post-flight processing of the telemetry information obtained from a board of the "Zarya" function-cargo block (FCB) are adduced which one has allowed not only to renovate actual motion of station in this mode, but also precisely enough to identify a means of control of turn, which one the manoeuvres implemented.

The research of an attitude of an international space station at the maiden stage of its deployment (up to a docking with the "Star" service module) has allowed to decide two primary goals: 1) recovery of nominal motion of angular-velocity vector reshaped according to a manner, realizable by a control system; 2) identification of a control manner of spatial turn of spacecraft, including definition of the law of motion of demanded angular velocity vector and numerical values of parameters of a control algorithm determining this motion.

The results of processing of the measuring information about parameters of rotary motion on ISS turns consisting both from one FCB "Zarya", and together with the "Unity" American module are adduced. The development of a method of teaching models has allowed to renovate demanded motion of station in a mode of programmed spatial turn and authentically to identify a means, which one the turn implemented. The consequences of mathematical processing of the telemetry information convincingly confirm, that at all turns the perspective means protected by the patent of Russian Federation utilised ї 2093433 (priority of 22.03.94). All process of turn actuates following milestones: boost, rotation with constant on value by angular velocity, braking. And, the motion of station on a main segment of turn (most continuous interval of time) takes place as simultaneous rotation around some fixed in all-inertial space of an axis component with a centerline of the spacecraft a computational angle , and around centerline of spacecraft with constant angular rates of precession љand proper rotation љThe control of turn of international station implemented by means of jet engines of orientation "Zarya", which one work in a pulse mode. Because of it the appearance of errors of improvement by a control system of demanded angular velocity is foregone. The ratings demonstrate, that the deviations value of actual angular rate from it calculated value, called by non-linearity of actuators, reach 0.003 - 0.005 deg./s. For this reason all are in viscid between the renovated functions of angular velocity and their telemetried values not superior to this value, can be true referred to errors of fulfilment by a system of actuators of control commands. Relevant applying for the practical goals and applications the precise definition of numerical rated values of parameters of a control algorithm by programmed turn of station is.