M.Yu.Belyaev, D.N.Rulev, E.S.Medvedev, V.V.Sazonov, V.Paeffgen||
Determination of Space Station Motion Parameters Using GPS Measurements||
We estimate the accuracy of determining the weakly disturbed orbital motion of International Space Station by use of GPS-measurements as well as the accuracy of forecasting such a motion. The measurements are the station coordinates in Greenwich coordinate system. They are received from on board equipment ASN-2401. The mean square errors of approximation of the measurements do not exceed 30 m when the motion is determined in a time interval less than a day. Processing the GPS-measurements in three-hour interval allows making the forecast of the motion on 15 hours forward with an error in the station radius vector not exceeding 400 m at a right choice of ballistic coefficient. Systematic errors in measurements of the station velocity, carried out by equipment ASN-2401, are revealed.
C.De Wagter, J. A. Mulder||
Vision-Based Guidance and Awareness for Autonomous UAV||
Motivated by the increasing computer power, the improving quality of digital imaging and the many unmanned aerial vehicles being developed, this paper proposes "camera images" in addition to absolute positioning and inertial measurements as source of information for the guidance and situation awareness of unmanned aerial vehicles. A fully GPS-IMU stabilized UAV helicopter is equipped with a single video camera, mounted on a pan-tilt device. The combination of IMU, GPS and magnetometer data with information subtracted from sequences of digital images significantly increases the situation awareness of the vehicle. To overcome the uncertainties inherent to vision and to create a robust system, a cognitive approach is used. Based on the idea that as long as the system knows the certainty of its observations it can react in accordance, the uncertainties are reduced using active vision. The vision-based awareness and guidance algorithms are tested in simulation while the image analysis algorithms are also tested in real life and can detect and track landing pads, provide guidance towards the objects of interest and can reconstruct 3D terrain information using a single camera. Finally the system can provide collision avoidance reflexes to avoid fatal collisions. The proposed system features a significant increase in awareness for a very modest weight and cost.
V.A.Andreev, S.A.Belousov, K.V.Dyuzhev, A.A.Ignatiev, L.Z.Novikov, V.L.Petelin, G.M.Shumova, A.N.Stolyarov ||
Strapdown Inertial Unit for Control System of Dnepr Self-Contained Booster Stage||
The paper deals with the progress of development of a small-sized strapdown inertial unit (SIU) based on miniature dynamically tuned gyros (DTG) and pendulous accelerometers meant to be used as a command and measurement device of Dnepr launcher self-contained booster stage (Space Tug) control system.
Particular attention has been given to redundancy principles of device structures that provide non-failure and continuous operation when any possible single malfunction occurs.
The system of SIU output data generation and mathematical software for the device operation in different modes are described.
Test results for the first pilot samples are presented. They validate engineering solutions adopted to achieve the performance objectives.
S.F.Konovalov, A.A.Konovchenko, E.L.Mezhiritsky ||
Balancing "Si-flex" Accelerometer Designed for Measuring High Accelerations||
The features of operation of gas-filled accelerometers of navigation class with the elastic suspension of the pendulum made of monocrystalline silicon are considered in the paper. It is shown that existence of non-coincidence between center of mass of the accelerometer pendulum and application point of the force produced by balancing force generator causes angular and translational displacements of the pendulum plate which values are comparable with the gap size of accelerometer gas damper and they are not compensated by accelerometer feedback system. As a result of this fact the accelerometer can lose its functionability at large accelerations. The fabrication and construction reasons of occurring indicated non-coincidence are analyzed. The pendulum suspension is suggested to be implemented by means of cross-shaped flexures made of monocrystalline silicon having high radial flexural stiffness to eliminate accelerometer functionability loss at high accelerations. The possible manufacturing of the pendulum with cross-shaped flexures made of monocrystalline silicon by a method of anisotropic etching was shown. Experimental results and figures of silicon pendulum with cross-shaped flexures are given in the paper as illustrations.
Yu.G.Martynenko, V.S.Ryabikov, N.N.Shcheglova, L.I.Nekhamkin||
Motion of the Two-degree-of-Freedom Gyro at Its Contacts with Stop||
The two-degree-of-freedom floated gyroscope established on the uniformly rotated basis is considered. The mathematical model of the gyro motion at its departure and returning to a unilateral constraint arising due to contact of a foramen on a float with an shaft-stop is constructed. The outcomes of a numerical integration of offered equations of motion are adduced.
Problems of strapdown attitude algorithms design. Part 1. Amplitude extension of algorithm application field||
The paper deals with a problem of attitude algorithms extension for high amplitude base vibration. Instead of classical coning motion, a new V - type of angular motion used as algorithms input is proposed to validate the accuracy of the strapdown digital integration algorithms. In its simplest form, this test motion assumes that the base oscillates about two axes that may be thought of as the axes of the gimbals. Being used this type of motion allows new important algorithm error sources to be revealed. Analytical approach is developed for analyzing the accuracy of conventional (truncated) attitude algorithms under such a type of input. The generalized algorithm error equation and amplitude - dependent residual error coefficient models are derived which describe system level errors rectified in inertial frame. Finally, the paper presents an analytical solution to the problem of extended algorithm design in which the contribution of the third term in the rotation vector equation is accounted for.
N.V.Drobyshev, V.N.Koneshov, I.A.Papusha, M.Yu.Popelensky, Yu.E.Rozhkov||
Rcurrent algorithm using gravimetric survey data for vertical deviation definition, based on stochastic approach||
Global models of the gravitation field are necessary for solving problems intended for large Earth areas. Global models of the gravitation field make it possible to achieve accuracies of altitude and geoid altitude abnormalities satisfying many applications. Plum deviation error is too large for geodetic applications. Error analysis shows that the only way to increase the accuracy is to use data with higher resolution, i.e. the gravimetric survey data.
The proposed method for vertical deviation calculation is based on the stochastic approach. This approach proceeds from the assumption that gravity abnormalities are stochastic variables with zero expectation. At that the abnormal field of gravitation is the uniform and isotropic field with known stochastic characteristics specified by covariance functions. Undoubted merits of this method are possibility of using iterative procedure making possible processing data obtained on vast areas and possibility of operating with different types of data particularly with aero gravimetric survey data carried out at different altitudes.
The traditional and proposed methods are compared at calculations of vertical deviations for the Eastern part of the Black Sea and Southern part of Ladoga Lake.
Proceedings of 8th Conference of Young Scientists
Navigation and Motion Control
International Public Association
The Academy of Navigation and Motion Control
All-Russian Workshop Up-to-date Methods of Navigation and Motion Control||
1st Russian Multi-Conference on the Problems of Control||
Conference on Dynamic Positioning
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