Optimal Use of GNSS Spacecraft in SBAS and GBAS Functional Augmentations

The article discusses a method for improving the quality of navigation services for consumers with increased requirements for accuracy and reliability using satellite-based augmentation systems (SBAS) and ground-based augmentation systems (GBAS). Augmentation systems provide users with corrections that are used to correct GNSS measurements and integrity information. Due to the existing restrictions on the number of satellites for which corrections are transmitted, the article proposes the optimal use of GPS satellites, which is an incomplete set of 27 satellites that will be used in the GLONASS/GPS/SBAS navigation service, while measurements of the full constellation of GLONASS satellites are used for positioning. It is proposed to carry out the choice of 27 from the existing constellation of 32 GPS satellites in such a way that the subsystem provides the maximum efficiency of using the GNSS signals. The optimization problem or finding the optimal set of excluded GNSS satellites is solved according to R. Bellman’s algorithm. The found optimal set of excluded GNSS satellites makes it possible to reduce VDOP in comparison with the non-optimal one by almost 24 % and thereby improve navigation performance using GLONASS/GPS signals and SBAS corrections.

Radio Frequency Support for Space Systems Based on Multi-Satellite Constellations Taking into Account the ITU-R Requirements and the WRC-19 Results

Deployment of space systems based on multi-satellite constellations to provide broadband Internet access and communication services acutely raises the question of their radio frequency support including issues of electromagnetic compatibility (EMC) between competing space systems using multi-satellite constellations (StarLink, OneWeb, Kuiper, etc.), their EMC with traditional space systems (satellite communication systems that employ spacecraft in geostationary and non-geostationary orbits, space systems of other services), as well as regulatory issues of entering into service and staged deployment of space systems. The article formulates the problematic issues of radio frequency support of modern space systems taking into account the trends of satellite constellations deployment and proposes the solutions with consideration to international and national requirements in the regulation of radio frequency spectrum including the ITU requirements and the requirements of Russian State Commission for Radio Frequencies. The paper shows the ways to share the radio frequency spectrum to meet new requirements of the World Radiocommunication Conference 2019 (WRC-19).

Mock-Up of Information Service for Automated Monitoring and Short-Term Forecasting of Severe Earthquakes in the Kamchatka-Sakhalin Region

The article is devoted to the analysis of the development and control of the operation of the functional mock-up of the information service for automated monitoring and short-term forecasting of severe earthquakes in the Kamchatka-Sakhalin region. The tasks of the service mock-up concerning the collection, processing of data on earthquake precursors, the forecasting of severe (earthquake magnitude 6 or more) earthquakes in the form of estimates of the times of their onset, coordinates of epicenters (latitude and longitude) and earthquake magnitudes are determined. Taking the geoinformational character of the initial data on the approaching earthquakes as the basis for constructing the mock-up of the service, a geo-integration platform is proposed. This allows the integration of the information resources of the earthquake precursor monitoring systems, the functions of processing monitoring information into earthquake forecasts, the results of generating earthquake forecasts and their presentation to consumers into a single geoinformation environment. The composition of the service mock-up and the functioning of such elements as microservices are considered: collection and processing data from receivers of radio navigation signals of the GPS/GLONASS systems; collection and processing of data on the global distribution of TEC in the ionosphere; collection and processing of data on geomagnetic conditions, the flux of solar radio emission, thermal anomalies, as well as data concerning the atmospheric anomalies over the test site area and a unit for presenting and communicating the results of the operation of the information service mock-up for automated monitoring and short-term forecasting of severe earthquakes. The results of service operation are illustrated with the help of examples of retrospective forecasting of a number of severe earthquakes that occurred over the past 10 years in the Kamchatka-Sakhalin region, according to their precursors.

Creation of a Hardware-Software Dynamic Signal Simulator of the Upgraded Inter-Satellite Radio Link of the GLONASS System

This work is aimed at creating a hardware-software signal simulator of the upgraded inter-satellite radio link (ISRL) of the GLONASS system. The simulator shapes ISRL signals with dynamically changing parameters of the Doppler frequency shift and delay, which correspond to the mutual dynamics of spacecraft (SC) motion of the GLONASS system. The upgraded inter-satellite radio link will provide (as compared to the current ISRL) an increase in the information transfer rate of up to four times, as well as boost the accuracy of measuring the distance between satellites by two times. Modernization consists in complementing the radio signal of the second orthogonal (phase-shifted carrier frequency by 90 degrees relative to the existing one) component. To modernize the ISRL, it is necessary to create and verify new equipment for receiving and transmitting signals of the upgraded ISRL of the GLONASS system. The simulator is designed to process measurement algorithms embedded in the on-board equipment for inter-satellite measurements and assess their consistency. Consistency evaluation consists in measuring and analyzing the difference between the Doppler parameters and delay introduced into the signal and the estimation of these parameters in the receiving equipment of the ISRL. This difference will be the measurement error. Dynamic simulation is performed for 24 system points, corresponding to GLONASS satellites, on the half-period of satellite revolution (20 280 seconds). The signal is generated at the input of the antenna-feeder device of one of the satellites in accordance with the information for generating the measuring signal, parameters of the transmitters of the signals of the upgraded ISRL and the almanac of the satellite constellation (because the signal at the input of the antenna-feeder device of the navigation receiver incomes from several SC) specified by the user.

Application of Radiation-Thermal Treatment to Suppress Sensitivity of Silicon Microcircuits to Single Radiation Effects

The paper analyses the possibility to reduce the sensitivity of silicon integrated circuits (ICs) to single radiation effects by means of radiation-thermal treatment including irradiation in charged particle accelerators and subsequent low-temperature heat treatment. It is shown that reduction in sensitivity to single radiation effects is provided by formation of thermostable recombination centers in semiconductor IC structure in necessary concentrations. At the same time a decrease in primary photocurrent generated by heavy charged particles or high-energy protons, reduction in transfer coefficients of parasitic bipolar transistors forming thyristor structures, reduction in carrier avalanche multiplication coefficients at high electric field strengths can be provided. Radiationthermal treatment can be introduced in the manufacturing process of ICs of various classes at the end of the manufacturing cycle and does not require correction of the basic technology. A possible undesirable growth of inverse currents and preservation of values of other electrical parameters within acceptable values when using radiation-thermal treatment is provided by choosing optimal modes of irradiation and annealing which are established in the course of experimental tests. The calculated evaluation has shown that using radiation-thermal treatment in the technology of IC fabrication can provide a decrease in the effective collection length of non-equilibrium charge carriers generated under the influence of single radiation effects by at least 10 times which allows considering radiation-thermal treatment as an effective technological tool to suppress the sensitivity to single radiation effects.

Key Navigation-Ballistic Technologies for Improving the Efficiency of Spacecraft Control

The article focuses on the issues of creating promising space technologies, their general characteristics, and special features. The basic principles for creating and implementing key navigation-ballistic technologies, which help ensure efficient control of spacecraft, are substantiated. A classification of the technologies is proposed based on the characteristics most often used in the area under consideration. Two bar charts of a typical technological cycle of navigation-ballistic support with the possibility of processing a joint sample of measurements of current navigation parameters and recurrent Kalman processing algorithms are analyzed. A variant of a general classification of technologies that allows singling out and correlating different types and classes of technologies is given. This contributes (especially at the early stages) to the improvement of the efficiency of their development.

Development of Control Module Based on a Computing IP-Core

The article presents the result of the implementation of a synthesized microcontroller in integrated circuits of small FPGAs and a variant of building a control system for an onboard control module based on the developed solution. The possibility of creating a full-fledged microcontroller based on a type 5578TC034 FPGA and more capacious microcontrollers is shown. The description of the structure of the microcontroller, processor core and periphery is given. The processor instruction system is presented. Ip-modules of peripheral devices and some interfaces have been developed. A variant of creating a control system using the developed microcontroller is proposed. In the future, it is planned to increase the functionality of the synthesized microcontroller by optimizing ip-modules and adding new ones. When developing the control system, a domestic component base was used.

Multi-Aperture Optical System of Photon Counting in the Image for Aberration-Free Space Debris Observations through a Turbulent Atmosphere (Part I)

The paper solves the problem of space debris monitoring to ensure the safety of space exploration. Space debris fragments are small-sized control objects with angular sizes up to 0.002 arcsecond. Therefore, optoelectronic systems of high resolution and permeability allowing one to measure the coordinates and recognize these weak control objects with a given accuracy and probability having integral brightness up to +18 stellar magnitude are necessary for the location (search, detection, measurement, and identification) of space debris fragments. To solve the optical location problems of space debris the Part I of the article proposes the concept of building a ground-based optoelectronic control system. The system consists of three consecutive and interrelated information channels: an image formation channel based on the matrix of individual telescopes and aperture synthesis technology; image detection channel based on scanning raster detectors and photon counting technology in the image; and image processing channel based on digital correlation compensation technology of atmospheric distortions. Advantages of a matrix of separate telescopes, photodetection and correlation processing are noted in the article. The proposed concept is protected by a patent of the Russian Federation, which is discussed in detail in Part II.

Research and Methodological Approaches to Solving the Problem of Enterprise Modeling based on the Conceptual Provisions of Digital Technologies

The article sets forth research and methodological approaches to solving the problem of enterprise modeling, of the production process, products and resources at all stages of the life cycle based on the conceptual provisions of digital technologies. With the help of methods and models of mathematical economics, systems analysis and systems theory, the issues of building a stable management system for a knowledge-intensive industry with account of resource degradation and recovery processes are considered. When describing the simulation model of the human resource component (one of the key components reflecting the readiness and ability of the organization to solve complex research and production problems), an area of concern in staffing — the relationship between the professional level of employees and educational and research support, personnel development is considered. The article focuses on the relationship between the state of the morale, which is mainly characterized by moral and psychophysical factors, and the quality management system in the model of a “virtual enterprise” operating in a single geographically distributed information space.

Integration of the SAR Payload on Board of the Meteor-M No. 2-2 Spacecraft into the COSPAS–SARSAT International Search and Rescue System

The present article addresses the results of the “Meteor-M” No. 2-2 SAR payload (RK–SM–MKA) commissioning campaign. The international effort was coordinated by Russia with the participation of technical teams from national administrations of the United States, Canada and France. In the course of testing, it was determined that the SAR payload performance was within technical expectations and that the SAR payload could be operationally used in the COSPAS–SARSAT system. Other matters of integrating the “Meteor-M” No. 2-2 (“Cospas-14” in Cospas-Sarsat terminology) SAR payload into the COSPAS–SARSAT system as well as the system’s readiness to accept the new spacecraft are discussed. The article also unveils the objectives addressed during the “Сospas-14” integration period and the benefits gained by the system, which were recently made public by the COSPAS–SARSAT Secretariat. The analysis performed by the Secretariat demonstrated that the addition of the new “Cospas-14” into the LEOSAR system significantly improves LEOSAR satellite latency due to the spatial diversity of the current SARSAT and “Cospas-14” orbits.