Determination Of Motion Parameters Research Articles

Model of Hybrid Satellite-Inertial Navigation System with Partial Structure

A mathematical model of a hybrid navigation system (GNS) consisting of a three-component block of linear newtonometers (accelerometers) physically simulating a vector-based measurer of non-gravitational nature forces and on-board GLONASS receivers that positioning a moving object in an ellipsoidal coordinate system is presented and investigated. The absence of a gyroscopic angular velocity sensors unit, traditional for the classical schemes of the inertial navigation method, and the presence of no more than two onboard satellite positioning devices (receivers) make it possible to characterize the considered GNS as a partial structure system. As a basic element of a mathematical model for estimating linear and angular parameters of an object’s motion, the developed procedure of multiple numerical differentiation of temporal data acquired from on-board satellite receivers, which functions stably irrespective of the magnitude of the discretization step of the problem in time, was used. The developed GNS makes it possible to qualitatively evaluate both the trajectory parameters (location, velocity, acceleration and forces causing the trajectory) as well as the parameters of the spatial orientation of the object (Euler-Krylov angles and its derivatives) with a two-positioning technique. The results of the computational experiment are given. The field of application of the research results is numerical-analytical planning of trajectories, determination of motion parameters and control of moving objects for various purposes and basing.

Analysis of interaction between a configurable stone and a water flow

Erosion and destruction of riverbeds, foundations of flooded engineering structures are accelerated during natural phenomena, accompanied by a significant increase in the rate and wetted perimeter of river flows, the acquisition of mobility by the riverbeds’ particles. We have analyzed the interaction between a water flow and a separate stone of spherical, cylindrical, pyramidal, and other configurations. In particular, we have further developed a traditional approach to determining the force action of fluid on a solid barrier, a stone, for the case of compression of a water jet and taking into consideration the relative flow around a stone with the predefined geometrical characteristics: diameter, volume, and configuration. It has been proposed to employ the following parameters for interaction between the flow of water and rocks of various configurations: a compression ratio and a streamline coefficient. We have derived analytical dependences of the flow rate limit, which sets a stone into motion, its weight, and configuration. For spherical smooth stones these ratios are identical with the classical results. The coefficients, introduced for consideration, were categorized, depending on the configuration of a single stone, in tables and charts, which is convenient to apply when calculating bank­protecting structures. It has been proposed to use a stone shape factor, which is the ratio of the actual flow rate limit, enabling the mobility of a stone of arbitrary configuration taking into consideration its streamlining, to the flow rate limit of a spherical stone of the same mass with a reduced diameter. A shape factor should be applied as an adjustment multiplier in the calculation of the minimum mass of stones for bank­protecting structures and during hydro­engineering works. For the wedge­shaped stones a value of the adjustment coefficient can sometimes amount to 0.170, which indicates high efficiency of applying such stones compared to those of spherical shape. In addition, the proposed coefficient could be used to refine the water flow rate limit in terms of loss of stability by existing bank­protecting structure. We have identified directions for further studies: analysis of the impact interaction between configurable stones and elements of bank­protecting structures; determination of motion parameters for water­stone flows

Determination of Motion Parameters for Rod Toothed Gears with Skew Axes

В работе рассматриваются приближенные передачи. Данная работа посвящена определению параметров движения зубчато-поводковой передачи на скрещивающихся осях. Разработка защищена патентом РФ. В статье обоснована актуальность синтеза новых видов зацепления с упрощенной геометрией контактирующих тел. Представлено расположение систем координат, использованных для получения функции положения передачи, состоящей из двух колес и неподвижного звена (стойки). Для передач на скрещивающихся осях получены координаты точек контакта на поверхностях поводков и рассчитаны ошибки функции положения при пересопряжении. Функция положения получена применением метода матричного преобразования систем координат и равенства радиусов-векторов и ортов нормалей в точке контакта. Данная передача может быть актуальна в машиностроении, приборостроении и других отраслях народного хозяйства. На ее основе могут быть синтезированы как редукторы, так и мультипликаторы. Она обладает высокой технологичностью (для ее изготовления не требуется специального оборудования), а функция перемещения близка к линейной. Данная статья характеризует влияние изменения передаточного отношения на качественные характеристики передачи. Определены минимальные допустимые передаточные отношения для различных чисел поводков ведущего колеса. Значения минимальных допустимых передаточных отношений существенно меньше, чем для конических зубчато-поводковых передач на пересекающихся ортогональных осях. Зацепление происходит без выхода точки контакта на кромку поводка. Для решения полученной системы уравнений применялись численные методы программного пакета MathCAD. В дальнейшем автором предполагается рассмотреть возможные погрешности монтажа и изготовления зубчато-поводковой передачи (такие, как погрешность шага, несоосность и т. д.) с целью оценки их влияния на качественные характеристики зацепления для всех типов взаимного расположения осей.

Simulation of Golf Realtime Tracking Based on Doppler Radar

Golf has become an increasingly popular sport. Determination of motion parameters of golf<br />ball can give quantitative suggestion for players. This paper introduces the principles of determination<br />based on Doppler radar. The parameters of golf motion to be measured include velocity, angle, spin<br />angular velocity and position. A golf realtime tracking system is designed with one transmitting antenna<br />and three receiving antennas in this paper. Simulations validate the feasibility and high accuracy<br />of this system. This system makes referential significance for golf realtime tracking system.

Study of observability of motion of an orbital group of navigation space system using intersatellite range measurements. I

The problem of specification of reference ephemeris (reference motion) using intersatellite range measurements on a given interval between spacecrafts of the space navigation system is formulated; observability for this problem is analyzed. Observability is the possibility of unambiguous determination of motion parameters of the orbital group of the space navigation system using known inter-satellite measurements on a given measurement interval. Linear approximate model describing the dependence between measurements and specified parameters are obtained for investigation of observability properties. In the framework of linear model problems of observability of motion of two any spacecrafts of the navigation system are studied using intersatellite range measurements.

Determination of motion parameters of a moving range sensor approximated by polynomials for rectification of distorted 3D data

Scanning by a moving range sensor from the air is one of the most effective methods to obtain range data of large-scale objects since it can measure some regions invisible from the ground. The obtained data, however, have some distortions due to the sensor motion during the scanning period. Besides these distorted range data, there should be available range data sets taken by other sensors fixed on the ground. Based on the overlapping regions visible from the moving sensor and the fixed ones, we propose an extended alignment algorithm to rectify the distorted range data and to align the data to the models by the fixed sensors. By using CAD models, we estimate the accuracy and effectiveness of our proposed method. Then we apply it to some real data sets to prove the validity of the method.

Autonomous navigation system of near-Earth spacecraft

An autonomous navigation system for near-Earth spacecraft is described; this system allows determination of the satellite orbit and prediction of its motion parameters. Radio navigation measurements of GLONASS and GPS satellite systems are used for this purpose. The autonomous navigation system is designated for operation on near-Earth orbits which do not go beyond the navigation areas of GLONASS and/or GPS and on orbits with large eccentricity whose apocenter is at a distance of 50–70 thousand km from the Earth’s surface. The developed methods and algorithms for orbit determination are based on the application of laws of motion dynamics of a spacecraft directly at processing primary phase measurements of the carrier frequency and code pseudo-range using an extended measurement base. Algorithms for determination of motion parameters of the spacecraft and results of simulation and operation of a model system are presented. The possibility of creation of an onboard autonomous navigation system with precision and reliability higher than those of the ground measuring complex is demonstrated.

Reliable and exact determination of motion parameters and acceleration field of a solid

Reliable and exact determination of motion parameters and acceleration field of a solid