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Described in the paper is a schematic design of an electronic linear controller of telegraph transmission-rate. It might serve as reference in the studies of marine main engine remote control.
摘要 :
Iospheric range delay is a potential limitation to GPS Wdie-Area Augment-ation System (WAAS). Navigation and positioning in WAAS with sing-frequency receivers suffers potentially from the unknown spatial variability of ionospheric...
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Iospheric range delay is a potential limitation to GPS Wdie-Area Augment-ation System (WAAS). Navigation and positioning in WAAS with sing-frequency receivers suffers potentially from the unknown spatial variability of ionospheric range delays. By using dual-frequency GPS reference receivers, it is possible to correct for most of the ionospheric range delay using WAAS real-time prediction algorithms.
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摘要 :
The ionospheric equivalent slab thickness (EST) is defined as the ratio of the total electron content (TEC) to the F2-layer peak electron density (NmF2) and it is a significant parameter representative of the ionosphere. Because i...
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The ionospheric equivalent slab thickness (EST) is defined as the ratio of the total electron content (TEC) to the F2-layer peak electron density (NmF2) and it is a significant parameter representative of the ionosphere. Because it contains TEC information, EST is also a very useful parameter for satellite navigation and positioning. In this paper, a statistical study of EST at Beijing is presented based on GPS-TEC and ionosonde NmF2 data during the year 2010–2017. The results show that:(1) The diurnal variation of EST in different seasons show great differences. The EST during the daytime is greater than that during the night time in summer, while the EST during the nighttime is larger than that during the daytime in winter. The EST variations in equinox are between them, and its value during the daytime is slightly larger than that in the nighttime. (2) The pre-sunrise peak of EST only occurs in winter, and it gradually weakens with the increase of solar activity. (3) The overall variation of EST in high solar activity years and low solar activity years is consistent. With the increase of solar activity, the average slab thickness during the day and night continues to decrease, and the influence of solar activity on the plate thickness at night is more significant. (4) The morphological change of the disturbance index (DI) of EST during magnetic storms is basically the same as its geomagnetic quiet period. The EST changes during the daytime are more stable, and the EST disturbances are more intense during the night time.
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摘要 :
The ionospheric equivalent slab thickness (EST) is defined as the ratio of the total electron content (TEC) to the F2-layer peak electron density (NmF2) and it is a significant parameter representative of the ionosphere. Because i...
展开
The ionospheric equivalent slab thickness (EST) is defined as the ratio of the total electron content (TEC) to the F2-layer peak electron density (NmF2) and it is a significant parameter representative of the ionosphere. Because it contains TEC information, EST is also a very useful parameter for satellite navigation and positioning. In this paper, a statistical study of EST at Beijing is presented based on GPS-TEC and ionosonde NmF2 data during the year 2010–2017. The results show that:(1) The diurnal variation of EST in different seasons show great differences. The EST during the daytime is greater than that during the night time in summer, while the EST during the nighttime is larger than that during the daytime in winter. The EST variations in equinox are between them, and its value during the daytime is slightly larger than that in the nighttime. (2) The pre-sunrise peak of EST only occurs in winter, and it gradually weakens with the increase of solar activity. (3) The overall variation of EST in high solar activity years and low solar activity years is consistent. With the increase of solar activity, the average slab thickness during the day and night continues to decrease, and the influence of solar activity on the plate thickness at night is more significant. (4) The morphological change of the disturbance index (DI) of EST during magnetic storms is basically the same as its geomagnetic quiet period. The EST changes during the daytime are more stable, and the EST disturbances are more intense during the night time.
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