Journal "Gyroscopy and Navigation" /  Books  
   "Gyroscopy and Navigation" №3 (38), 2002
 
 

CONTENTS

V.E. Hertzman, V.V. Chistyakov Anomaly Measurements Rejection Technique for Space Vehicle Trajectory Determination Based on GPS/GLONASS Data 3
The following aspects of the anomaly measurements rejection for the GPS/GLONASS user equipment based on a board of the space boosters, are con-sidered: the pre-computations of the signal reception conditions, the methods of the failure detection and exclusion in real-time and post-mission processing. The precomputations have the goal to determine the trajectory sectors (flight time intervals) with critical conditions of the signal reception. The methods of the measurements rejection in real-time processing are based on the analysis of the signal-to-noise density of the measurement errors and comparison of the least-squares residual's sum with the permissible bounds. Chi-square distribution of the probability is used for determination of the permissible bounds. The methods of the measurements rejection in post-mission processing are based on the analysis of the residuals, determined by polynomial smoothing in the sliding time intervals. The results of the anomaly measurements processing are illustrated on the data obtained from GPS/GLONASS receiver "Terminator"
.. Odintsov, V.B. Vasilieva, Yu.E. Naumov Errors of marine inertial navigation systems based on corrected magnetic spherical gyros 11
The errors caused by the unsuspected drift of the controllable magnetically suspended gyro, and log errors for semianalytical INS with azimuth rotation of a gyro stabilized platform (GSP), based on two two-degree magnetically suspended gyros are analysed in the paper. Analytical expressions based on the given model of magnetically suspended gyro drift are given for generation errors of heading, position and speed components under the assumption of sufficiently slow drift model coefficients change in comparison with the GSP rotation period. Error equations acquired in [1] are used for obtaining error expressions. Error expressions are presented for INS operation in the geographical coordinate system. Design equations (15-20) presented in the paper make it possible to define analytically the error steady-state values of the sea-born gimbal INS on the controlled gyros with azimuth rotation of GSP. This gives an opportunity for an easy and obvious analysis of disturbing factors' influence on generation errors of INS output parameters. Tables 1-6 contain the results of corresponding parameter calculations of INS error equations. Conclusions are made for either factor influence on INS operation accuracy.
V.A. Tupysev Using Wiener Models for Describing Gyro Drifts and Measurement Errors in INS State Estimation 23
The comparative analysis of INS error behavior has been carried out for the case that Wiener and Markov models of gyro drifts and measurement errors are used to adjust Kalman filter.
Presented are the conditions for adjusting the filter that allow guaranteed estimation of the INS state under dynamic uncertainty in describing gyro drifts and measurement errors.
It is shown that Kalman filter adjustment to Wiener models is more preferable from the practical point of view, as it provides effective estimation of the INS state both in the cases that real processes have Markov properties and that their behavior is stepwise.
O.A. Stepanov, B.A. Blazhnov, D.A. Koshaev The Efficiency of Using Satellite Measurements in Determining Gravity Aboard an Aircraft 33
The paper considers the problem of gravity disturbance estimation solved by using the data from a gravimeter and phase and Doppler measurements from the satellite navigation system in the differential mode. The optimal solution of this problem is compared to the most commonly used solution in which the differences between the data from the gravimeter and derivatives from satellite measurements are processed with Butterworth filters in direct and in reverse time. The accuracy of gravity disturbance estimation is analysed for various gravity models and various (phase or Doppler) measurements. The effect of ambiguity of phase measurements on the accuracy of gravity disturbance estimation is investigated. Besides the analytical calculations, the paper presents and discusses the results obtained in the processing of the real air gravity survey data
M.A. Barulina, V.E. Dzhashitov, V.M. Pankratov Mathematical Models of Thermal Control Systems for Micromechanical Gyros 48
In this paper set and investigated the problem of creation of active thermal control systems (TCS) of the micromechanical gyroscopes (MMG) providing at the minimal energy consumption, maintenance of the given temperature of the device in conditions of the determined and casual thermal influences. Nonlinear mathematical models reversive on semi-conductor Peltyer's thermocouples or on heating elements of thermal control systems of micromechanical gyroscopes are constructed. Analytical and computer research of the constructed models is carried out, qualitative and quantitative estimations of functioning of systems MMG - TCS are received at complex temperature influences

Materials of the 9th Saint Petersburg International Conference
on Integrated Navigation Systems

J. Furthner GALILEO - Only a Better GPS or More? Performance Analysis with the Tool NAV-SIM 60
Since the European Commission (EC) decided to built up an own civil global navigation satellite system called Galileo, many people are asking why the EC want to built up an additional system. They say that they can use without any costs the U.S. navigation system GPS and, therefore, there is no need for the European GALILEO for the applications. But this is not really true. For some special applications GPS is not utilisable because it is no guarantee for the availability of the system.
B. Eissfeller, C. Tiberius,
T. Pany, R. Biberger,
T. Schueler, G. Heinrich
Instantaneous Ambiguity Resolution for GPS/Galileo RTK Positioning 71
We review the planned modernization of the Global Positioning System (GPS) and the development of the European Galileo system, thereby concentrating on the high-precision carrier phase and code signals eventually available to the GNSS user community for fast and precise Real-Time Kinematic (RTK) positioning.
High-precision GNSS positioning results are obtained with carrier phase measurements, once the integer cycle ambiguities have been successfully resolved using also code measurements. A geometry free and a geometry based approach for ambiguity resolution are discussed. The first approach is conceptual simple but we will show that high ambiguity success rates for a combined hybrid GPS/Galileo system can only be obtained with the second one. The reason is that all ranges are linked to the same three baseline coordinate unknowns, instead of dealing with a double difference range unknown per satellite-pair.
RTK positioning requires forming of double differences of carrier phase and code observations between two satellites, a reference station and the roving receiver. Three scenarios (short, medium and long baseline) are discussed. The categorization refers to the baseline length (<3 km, 20 km and 400 km) but more important than baseline length are atmospheric conditions which are characterized by double differenced tropospheric and ionospheric delays.
Ambiguity success rates for each scenario and for each satellite configuration are calculated as a function of time for a whole day. Each attempt to resolve ambiguities relies on data from only one epoch, i.e. we consider instantaneous ambiguity resolution. The method to calculate (instantaneous) success rates is a based on an approximation called bootstrapping, a sequential process in which ambiguities are fixed (hard-constrained) to integers one-by-one, each time accounting for the statistical correlation with the remaining ambiguities.
As a result we find a decrease of the ambiguity fail rate (i.e. one minus success rate) for a 4 frequency hybrid GPS/Galileo system compared to the dual frequency GPS system. The improvement is largest for the short baseline scenario where the fail rate decreases from 0.24 % to less than 0.000001 %. For medium baseline lengths it decreases from 63% to 6% and no improvement can be seen for long baselines. The improvement is attributed mainly to the increased number of satellites and to the improved geometry. The main performance limiting factors are the uncertainty in the ionospheric delay and to less extend the code measurement error.
The ultra high instantaneous ambiguity success rate for short baselines opens new fields of applications for RTK positioning like avionics. In that fields the high RTK positing accuracy might yield new applications of satellite based navigation
B.A. Blazhnov, L.P. Nesenjuk,
V.G. Peshekhonov, A.V. Sokolov,
L.S. Elinson, L.K.Zheleznyak
An Integrated Mobile Gravimetric System. Development and Test Results 92
It is represented mobile gravimeter, which is evolution of sea gravimetric systems created by CSRI "Elektropribor" during thirty years. It is considered the principle of the gravity sensor design based on the double quartz elastic system with the optic-electronic converter, in which charge couple devices of linear type are used as a photodetector. The float gyros with accelerometers correction are used in the gyroplatform of the gravimeter. The gyroplatform control system uses the builtin microcontrollers. The mobile gravimeter is integrated with satellite navigating system. It is analyzed the results of bench tests and pre-production operation of the first sample of the mobile gravimeter onboard the geophysical vessel which is carrying out marine seismic works with a view to search of oil and gas accumulation
V.N. Berzhitzky, V.N. Ilyin,
E.B.Saveliev, Y.L. Smoller,
S.S. Yurist, Yu.V. Bolotin,
A.A.Golovan, N.A.Parusnikov,
G.V. Popov, M.V. Chichinadze
GT-1A Inertial Gravimeter System Design Experience and Results of Flight Tests 104
A brief description of the functional scheme, system organization and software operation of the GT-1A inertial gravimeter, developed by JSK STC "Gravimetric Technologies", is given. The software system for processing of airborne gravimetry data, developed by MSU Laboratory of Control and Navigation, is described. The results of laboratory and flight tests are discussed.

Materials of the 4th Conference of Young Scientists
on Navigation and Motion Control

Abstracts of lectures and papers                   117    

International Public Association
The Academy of Navigation and Motion Control
Official Information

To the 90th anniversary from .Magnus' birth                   149    

Information

Materials of the joint meeting of the Bureau of Navigation Systems and Their Sensors Section and the Saint Petersburg Section of Precise Gyroscopy of the RAS scientific council on the problems of motion control and navigation
151    
Russian and International Conferences, Symposiums, and Exhibitions
152    

New books

S.P. Dmitriev, A.E. Pelevin       "Guidance and Control Problems of Marine Vehicle Track-Keeping"
155    
E.I.Veremei           Review of the book by S.P. Dmitriev, A.E. Pelevin "Guidance and Control Problems
of Marine Vehicle Track-Keeping"

156    

The abstracts of the papers presented here
are available in Russian and English
at http://www.elektropribor.spb.ru (Section "Publications")
 
 
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Last updated October 20, 2002