Management of Celestial Systems under Spatial Grasp Model

Many governmental agencies and private companies of different countries are now rushing into space around Earth in hope to provide smart communication, industrial, security, and defense solutions. This often involves massive launches of cheap small satellites which are also contributing to the growth of space debris. The current paper discusses how the developed high-level system philosophy and model can effectively organize distributed space-based systems on different stages of their development and growth. The briefed Spatial Grasp Technology, based on parallel pattern-matching of distributed environments with high-level recursive mobile code, can effectively provide any networking protocols and important applications of large satellite constellations, especially those on Low Earth Orbits. The paper contains examples of technology-based solutions for establishing basic communications between satellites, starting from their initial, often chaotic, launches and distributing and collecting data in the growing constellations with even unstable and rapidly changing connections between satellites. It describes how to organize and register networking topologies in case of predictable distances between satellites, and how the fixed networking structures can help in solving complex problems. The latter including those related to the new Space Development Agency multiple-satellite defense-oriented architecture and allowing for effective integration of its continuous earth custody observation and cooperative missile tracking and elimination layers, based on self-spreading mobile intelligence. Earlier versions of the technology, described in many papers, six books including, were prototyped and used in different countries, with the current one quickly implementable too, even in university-based environments.

Tropospheric Attenuation in GeoSurf Satellite Constellations

In GeoSurf satellite constellations, any transmitter/receiver, wherever it is located, is linked to a satellite with zenith paths. We have studied the tropospheric attenuation predicted for some reference sites (Canberra, Holmdel, Pasadena, Robledo, and Spino d’Adda), which also set the meridian along which we have considered sites with latitudes ranging between 60° N and 60° S. At the annual probability of 1% of an average year, in the latitude between 30° N and 30° S, there are no significant differences between GEO slant paths and GeoSurf zenith paths. On the contrary, at 0.1% and 0.01% annual probabilities, large differences are found for latitudes greater than 30° N or 30° S. For comparing the tropospheric attenuation in GeoSurf paths with that expected in LEO highly variable slant paths, we have considered, as reference, a LEO satellite constellation orbiting in circular at 817 km. GeoSurf zenith paths “gain” several dBs compared to LEO slant paths. The more static total clear-sky attenuation (water vapor, oxygen, and clouds) in both GEO and LEO slant paths shows larger values than GeoSurf zenith paths. Both for rain and clear-sky attenuations, Northern and Southern Hemispheres show significant differences.

Artificially Induced Phase Scintillation Observed From GLONASS Signals

The phase scintillation index is a commonly used metric in the remote sensing of ionospheric irregularities. In this work, we analyze the phase scintillation index observed from the GPS, GLONASS, Galileo, and BeiDou satellite constellations, for a continuous period of three years. Our analysis reveals an elevated level of L1 phase scintillation observed from most GLONASS satellites, and non of the other GNSS constellations during the same period. This is of particular interest as the abnormality was observed during a solar minimum period, and from satellites labeled as healthy. Furthermore, the observations made were verified with data from three other receivers in different regions. This study was conducted to highlight these artificially induced phase scintillations from GLONASS satellites so that future studies can take them into considerations, especially during periods of heightened geomagnetic activity. Additionally, these artificially induced phase scintillations may result in loss of phase lock, as well as reduced positioning accuracy, which may have serious effects on the reliability and integrity of the GLONASS positioning service.

Artificially Induced Phase Scintillation Observed From GLONASS Signals

The phase scintillation index is a commonly used metric in the remote sensing of ionospheric irregularities. In this work, we analyze the phase scintillation index observed from the GPS, GLONASS, Galileo, and BeiDou satellite constellations, for a continuous period of three years. Our analysis reveals an elevated level of L1 phase scintillation observed from most GLONASS satellites, and non of the other GNSS constellations during the same period. This is of particular interest as the abnormality was observed during a solar minimum period, and from satellites labeled as healthy. Furthermore, the observations made were verified with data from three other receivers in different regions. This study was conducted to highlight these artificially induced phase scintillations from GLONASS satellites so that future studies can take them into considerations, especially during periods of heightened geomagnetic activity. Additionally, these artificially induced phase scintillations may result in loss of phase lock, as well as reduced positioning accuracy, which may have serious effects on the reliability and integrity of the GLONASS positioning service.

RAPID TESTING: ANALYSIS OF GNSS RAPID STATIC OBSERVATIONS SUITABILITY FOR ENGINEERING SURVEYS IN URBAN ENVIRONMENTS IN THE TIME OF COVID-19

This study aims to determine which rapid static observation durations would have acceptable accuracy for engineering surveys in urban environments (i.e. Metro Manila) in the time of COVID-19. Due to health concerns caused by the COVID-19 pandemic, Metro Manila has experienced various restrictions in mobility and time spent in public spaces in recent months. This has affected not only the lives and ways of work of the so-called front liners like nurses, doctors, and primary health care workers, but also the public at large which includes Land Surveyors. It is for this reason that this study was conducted, since a balance must be struck between the aim to get accurate engineering survey results and the health and safety of those who are conducting the measurements. Hence, the shortest possible time to conduct rapid static GNSS observation durations with acceptable results must be determined while ensuring that the conduct of the field survey would still be in compliance to the minimum health protocols (i.e. no mass gathering, maintenance of physical distancing, short time of interaction, etc.) set by the national government.For this study, rapid static observations were made at varying time intervals (i.e. 2 minutes, 5 minutes, 10 minutes, 15 minutes, 30 minuntes, 1 hour, and 2 hours) at locations (i.e. open, with minimal obstructions, with significant obstructions) that would simulate archetypal situations when conducting engineering surveys in urban environments. Results were computed using fully constrained least square adjustment and results show that if all GNSS satellites are used in the computations, all time intervals would yield acceptable RMSE values, both for the horizontal (5 mm to 2 cm) and vertical (1 cm to 4 cm), for engineering surveys. However, if not all GNSS signals are available, it is best to use at least two GNSS satellite constellations (i.e. GPS-BeiDou, GPS-Glonass, Glonass-BeiDou) so that rapid static observations with acceptable accuracy can be made for as short as 5 minutes. For the “classical” accuracy standards, all rapid static observation durations yielded Order B relative precisions for the horizontal while most, except for the 30-minute duration, which yielded Third Order level results for the vertical.

Design Coverage Optimization Based on Position of Constellations and Cost of the Launch Vehicle

This research will analyze the tradeoffs between coverage optimization based on Position dilution of precision (PDOP) and cost of the launch vehicle. It adopts MATLAB and STK tools along with multiple objective genetic algorithms (MOGA) to explore the trade space for the constellation designs at different orbital altitudes. The objective of optimal design solutions is inferred to determine the economic and efficient LEO, MEO, HEO or hybrid constellations and simulation results are presented to optimize the design of satellite constellations. The benefits of this research are the optimization of satellite constellation design, which reduces costs and increases regional and global coverage with the least number of satellites. The result of this project is the optimization of the number of constellation satellites in several orbital planes in LEO orbit. Validations are based on reviewing the results of several simulations. The results of graphs and tables are presented in the last two sections and are taken from the results of several simulations.

In-orbit demonstration of an iodine electric propulsion system

Propulsion is a critical subsystem of many spacecraft1–4. For efficient propellant usage, electric propulsion systems based on the electrostatic acceleration of ions formed during electron impact ionization of a gas are particularly attractive5,6. At present, xenon is used almost exclusively as an ionizable propellant for space propulsion2–5. However, xenon is rare, it must be stored under high pressure and commercial production is expensive7–9. Here we demonstrate a propulsion system that uses iodine propellant and we present in-orbit results of this new technology. Diatomic iodine is stored as a solid and sublimated at low temperatures. A plasma is then produced with a radio-frequency inductive antenna, and we show that the ionization efficiency is enhanced compared with xenon. Both atomic and molecular iodine ions are accelerated by high-voltage grids to generate thrust, and a highly collimated beam can be produced with substantial iodine dissociation. The propulsion system has been successfully operated in space onboard a small satellite with manoeuvres confirmed using satellite tracking data. We anticipate that these results will accelerate the adoption of alternative propellants within the space industry and demonstrate the potential of iodine for a wide range of space missions. For example, iodine enables substantial system miniaturization and simplification, which provides small satellites and satellite constellations with new capabilities for deployment, collision avoidance, end-of-life disposal and space exploration10–14.