T.A. Brovko1, E.M. Liubchenko2, A.P. Malyshev3, V.B. Pudlovsky4

1-4 V.A. Kotelnikov Institute of Radio Engineering and Electronics RAS (Moscow, Russia)
1-4 National Research University «Moscow Power Engineering Institute» (Moscow, Russia)
1 BrovkoTA@mpei.ru; 2 LiubchenkoEM@mpei.ru; 3 MalyshevAP@mpei.ru

Global Navigation Satellite Systems (GNSS) are complex structures that include space, ground, and user segments, which together ensure the generation, transmission, and utilization of navigation and timing information [1]. All elements of these systems interact closely, providing continuous and accurate transmission of navigation data. Modern GNSS, including the Russian GLONASS system, play a key role in various sectors. With the constant growth of requirements for navigation accuracy and reliability, GNSS continue to evolve and become increasingly sophisticated.

In recent years, the Russian GLONASS system has undergone active modernization, including the transition to new signal types, improvement of ephemeris-time support, and development of the differential correction and monitoring system (SDCM). Given the increasing demands on navigation precision and reliability, the analysis of factors influencing the accuracy of coordinate and time determinations (CTD), including errors in satellite ephemerides and onboard clocks, becomes particularly relevant [2]. However, conducting full-scale experiments to verify and substantiate proposed solutions requires significant financial and technical resources. Therefore, the use of simulation modeling methods becomes an effective tool for analyzing and predicting the behavior of such systems under various conditions. At present, there is no complete mathematical model of the GLONASS global navigation satellite system.

Mathematical modeling of GLONASS is currently essential for solving a wide range of tasks, primarily those related to determining optimal directions for system development in the future. However, most existing works focus on constructing the orbital constellation to improve satellite availability and reduce the average value of the geometric dilution of precision (GDOP). These studies often do not pay sufficient attention to other factors that directly determine the system’s performance for its intended purpose — particularly, the errors of coordinate and time determinations (CTD).

Simulation models make it possible to investigate the influence of various factors — orbital perturbations, errors in ephemeris-time and frequency-time support, and radio signal propagation conditions — on the accuracy of navigation solutions [3, 4]. Of particular importance are models describing the behavior of satellite time scales. For instance, the results of study [5] demonstrate that applying a prediction model for onboard clock drift improves the accuracy of ephemeris-time support. This confirms the feasibility of incorporating models for predicting ephemeris-time parameters into GNSS simulation frameworks.

In this work, the authors use a previously developed simulation model of the GLONASS system [6, 7]. Since simulation models enable the reproduction of the operation of individual subsystems and the evaluation of how different factors affect the overall navigation performance, it becomes possible to estimate pseudorange errors by modeling navigation-time support (NTS) errors in GLONASS signals. Specifically, the study focuses on developing an ephemeris-time support (ETS) error model that reproduces realistic patterns of orbital and clock errors of navigation satellites. The development and integration of this model into the simulation framework are aimed at improving the reliability of modeling results and providing a tool for further research on enhancing the performance of the GLONASS system.

Brovko T.A., Liubchenko E.M., Malyshev A.P., Pudlovsky V.B. Development of the ephemeris-time support error model in the GLONASS simulation model. Achievements of modern radioelectronics. 2026. V. 80. № 3. P. 65–73. DOI: https://doi.org/10.18127/j20700784-202603-09 [in Russian]

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