Добірка наукової літератури з теми "Ionosphere Computer programs"

The work is devoted to solving an urgent problem - the development of a computer model of the energy consumption system of the Institute of the ionosphere of the National Academy of Sciences and the Ministry of Education and Science of Ukraine in order to solve the problem of increasing the energy efficiency of the measuring complex. The power supply system of the complex is described, a generalized structural diagram of the loads - powerful consumers of electricity is presented. The graphs characterizing the energy consumption of individual powerful loads are presented, the problem of compensating the reactive power of loads is shown. The adequacy of the developed model is confirmed by the coincidence of the shape and values of the experimentally obtained characteristics on loads with the characteristics of the model. The model adequacy was assessed by the variance of feedback deviations from the system mean. The results obtained confirmed the possibility of using the developed Matlab-model of the energy consumption system of the measuring complex for creating and testing on the model of an energy-efficient power supply system, which will ensure the stable operation of scientific equipment for the implementation of research programs of the NAS of Ukraine.

Abstract. The Millstone Hill Incoherent Scatter Data Acquisition System (MIDAS) is based on an abstract model of an incoherent scatter radar. This model is implemented in a hierarchical software system, which serves to isolate hardware and low-level software implementation details from higher levels of the system. Inherent in this is the idea that implementation details can easily be changed in response to technological advances. MIDAS is an evolutionary system, and the MIDAS hardware has, in fact, evolved while the basic software model has remained unchanged. From the earliest days of MIDAS, it was realized that some functions implemented in specialized hardware might eventually be implemented by software in a general-purpose computer. MIDAS-W is the realization of this concept. The core component of MIDAS-W is a Sun Microsystems UltraSparc 10 workstation equipped with an Ultrarad 1280 PCI bus analog to digital (A/D) converter board. In the current implementation, a 2.25 MHz intermediate frequency (IF) is bandpass sampled at 1 µs intervals and these samples are multicast over a high-speed Ethernet which serves as a raw data bus. A second workstation receives the samples, converts them to filtered, decimated, complex baseband samples and computes the lag-profile matrix of the decimated samples. Overall performance is approximately ten times better than the previous MIDAS system, which utilizes a custom digital filtering module and array processor based correlator. A major advantage of MIDAS-W is its flexibility. A portable, single-workstation data acquisition system can be implemented by moving the software receiver and correlator programs to the workstation with the A/D converter. When the data samples are multicast, additional data processing systems, for example for raw data recording, can be implemented simply by adding another workstation with suitable software to the high-speed network. Testing of new data processing software is also greatly simplified, because a workstation with the new software can be added to the network without impacting the production system. MIDAS-W has been operated in parallel with the existing MIDAS-1 system to verify that incoherent scatter measurements by the two systems agree. MIDAS-W has also been used in a high-bandwidth mode to collect data on the November, 1999, Leonid meteor shower.Key words: Electromagnetics (instruments and techniques; signal processing and adaptive antennas) – Ionosphere (instruments and techniques)

Durante a propagação entre a antena dos satélites e a antena do receptor, os sinais GNSS interagem com partículas eletricamente carregadas, bem como com moléculas e átomos neutros, presentes na atmosfera terrestre. Isto causa refrações e distúrbios na potência e na forma do sinal que provocam variações na velocidade, na amplitude, na fase e na direção de propagação, deteriorando a qualidade do posicionamento. No entanto, é importante salientar que se por um lado a atmosfera afeta negativamente o posicionamento por satélites, por outro, os sinais GNSS vem sendo utilizados como sensores deste meio, o que permite modelar e reduzir tais efeitos negativos. Destaca-se que o atraso ionosférico de primeira ordem, responsável por mais de 99% deste atraso, é proporcional ao Conteúdo Total de Elétrons (TEC), o qual pode ser calculado a partir de observações GNSS. Neste sentido, a RBMC representa uma importante infraestrutura para se obter tal quantidade. Um dos modelos desenvolvidos para se determinar o TEC assume que ele esteja totalmente concentrado em uma camada esférica infinitesimalmente fina e de altitude pré-definida, normalmente entre 300 km e 450 km. Neste caso, o TEC é calculado na intersecção do vetor satélite-receptor com esta camada, denominado de ponto ionosférico (IPP - Ionospheric Pierce Point). Até 2012, a RBMC possuía 88 estações número este elevado para 112 em 2014. Esta pesquisa visa mostrar o impacto da densificação da RBMC entre 2012 e 2014 sobre a quantidade e cobertura temporal dos pontos ionosféricos considerando as constelações GPS e GLONASS, onde o programa grid simulator é utilizado.