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Słowa kluczowe GNSS relativistic effects

Abstrakt

Study of the trajectories of the motion of satellites remains an urgent task for modern science. This is especially true for GNSS systems and for satellites intended for Earth remote sensing. The basis of their operation is to accurately determine the position of the satellite, and the parameters of signal propagation. Considering the great distances and speeds of both satellites and the Earth in calculating these parameters, it is necessary to take into account the special and general theory of relativity. In the article formulas have been derived for calculating additional corrections for relativistic effects. A mathematical model for calculating the metric tensor was created. A sequence of correction was also proposed.
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Abstrakt

A significant threat to critical infrastructure of computer systems has a destructive impact caused by infrasound waves. It is shown that the known infrasound generations are based on using the following devices: a Helmholtz Resonator, Generation by using a Pulsating Sphere such as Monopolies, Rotor-type Radiator, Resonating Cylinder, VLF Speaker, Method of Paired Ultrasound Radiator, and airscrew. Research of these devices was made in this paper by revealing their characteristics, main advantages and disadvantages. A directional pattern of infrasound radiation and a graph of dependence of infrasound radiation from the consumed power was constructed. Also, during the analysis of these devices, there was proven a set of basic parameters, the values of which make it possible to characterize their structural and operational characteristics. Then approximate values of the proposed parameters of each those considered devices, were calculated. A new method was developed for evaluating the effectiveness of infrasound generation devices based on the definition of the integral efficiency index, which is calculated using the designed parameters. An example of practical application of the derived method, was shown. The use of the method makes it possible, taking into account the conditions and requirements of the infrasound generation devices construction, to choose from them the most efficient one.
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