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931.
T.A. Jacobsen J. Tr∅im B.N. Maehlum M. Friedrich 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):123-127
A “mother-daughter” rocket code-named “Electron 2” was launched from And?ya, Northern Norway in November, 1978. The “daughter”, carrying a 10 keV electron accelerator, was separated from the “mother” payload with a speed of 0.4 m/s. A series of plasma diagnostic instruments were included on the “mother” to study effects produced by the interaction between the electron beam and the ionospheric plasma. Results obtained by two different plasma probes are presented. It was found that pronounced changes in the ambient electron population took place in regions penetrated by the electron beam. Estimates of the dimensions of the disturbed region are presented. 相似文献
932.
A Comparison of Complementary and Kalman Filtering 总被引:1,自引:0,他引:1
A technique used in the flight control industry for estimation when combining measurements is the complementary filter. This filter is usually designed without any reference to Wiener or Kalman filters, although it is related to them. This paper, which is mainly tutorial, reviews complementary filtering and shows its relationship to Kalman and Wiener filtering. 相似文献
933.
934.
T. J. Ponman 《Space Science Reviews》1981,30(1-4):353-360
Evidence for periodicities of several days in the three bright galactic bulge sources GX349+2, GX17+2 and Ser X-1 has been found in Ariel V RMC data collected over 4 years. 相似文献
935.
H. Saito Y. Masumoto T. Mizuno A. Miura M. Hashimoto H. Ogawa S. Tachikawa T. Oshima A. Choki H. Fukuda M. Hirahara S. Okano 《Acta Astronautica》2001,48(5-12)
This paper describes outline of the piggy-back satellite “INDEX” for demonstration of advanced satellite technologies as well as for observation of fine structure of aurora. Aurora observation will be carried out by three cameras(MAC) with a monochromatic UV filter. Electron and ion spectrum analyzer (ESA/ISA) will measure the particle phenomena together with the aurora imaging. INDEX satellite will be launched in 2002 by Japanese H2-A. The satellite is mainly controlled by the high-speed, fault-tolerant on-board RICS processor (three-voting system of SH-3). The attitude control is a compact system of three-axis stabilization. Although the size of INDEX is small (50Kg class), several newly-developed technologies are applied to the satellite system, including silicon-on-insulator devices, variable emittance radiator, solar-concentrated paddles, lithium-ion battery, and GPS receiver with all-sky antenna-coverage. 相似文献
936.
937.
H. O. Funsten R. M. Skoug A. A. Guthrie E. A. MacDonald J. R. Baldonado R. W. Harper K. C. Henderson K. H. Kihara J. E. Lake B. A. Larsen A. D. Puckett V. J. Vigil R. H. Friedel M. G. Henderson J. T. Niehof G. D. Reeves M. F. Thomsen J. J. Hanley D. E. George J.-M. Jahn S. Cortinas A. De Los Santos G. Dunn E. Edlund M. Ferris M. Freeman M. Maple C. Nunez T. Taylor W. Toczynski C. Urdiales H. E. Spence J. A. Cravens L. L. Suther J. Chen 《Space Science Reviews》2013,179(1-4):423-484
The HOPE mass spectrometer of the Radiation Belt Storm Probes (RBSP) mission (renamed the Van Allen Probes) is designed to measure the in situ plasma ion and electron fluxes over 4π sr at each RBSP spacecraft within the terrestrial radiation belts. The scientific goal is to understand the underlying physical processes that govern the radiation belt structure and dynamics. Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔE FWHM/E≈15 %. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight (TOF) mass spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels coplanar with the spacecraft spin axis, and up to 16 azimuthal bins are acquired for each polar pixel over time as the spacecraft spins. Ion and electron measurements are acquired on alternate spacecraft spins. HOPE incorporates several new methods to minimize and monitor the background induced by penetrating particles in the harsh environment of the radiation belts. The absolute efficiencies of detection are continuously monitored, enabling precise, quantitative measurements of electron and ion fluxes and ion species abundances throughout the mission. We describe the engineering approaches for plasma measurements in the radiation belts and present summaries of HOPE measurement strategy and performance. 相似文献
938.
B.T. Kress J.V. Rodriguez J.E. Mazur M. Engel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Solar energetic particle (SEP) cutoffs at geosynchronous orbit are sensitive to moderate geomagnetic activity and undergo daily variations due to the day–night asymmetry of the magnetosphere. At geosynchronous orbit, cutoff rigidity also has a large directional dependence, with the highest cutoff rigidity corresponding to ions arriving from magnetic east and lowest cutoff rigidity corresponding to ions incident from the west. Consequently, during geomagnetically quiet periods, the SEP flux observed by an eastward facing particle detector is significantly lower than observed by a westward facing particle detector. During geomagnetically disturbed periods the cutoff is suppressed allowing SEPs access well inside of geosynchronous, so that the east–west SEP flux ratio approaches unity. Variations in the east–west SEP flux ratio observed by GOES Energetic Particle Sensors (EPS) have recently been reported by Rodriguez et al. (2010). In NOAA’s operational processing of EPS count rates into differential fluxes, the differential flux is treated as isotropic and flat over the energy width of the channel. To compare modeled SEP flux with GOES EPS observations, the anisotropy of the flux over the EPS energy range and field of view must be taken into account. A technique for making direct comparisons between GOES EPS observations and SEP flux modeled using numerically computed geomagnetic cutoffs is presented. Initial results from a comparison between modeled and observed flux during the 6–11 December 2006 SEP event are also presented. The modeled cutoffs reproduce the observed flux variations well but are in general too high. 相似文献
939.
Results of observations of ion-cyclotron (IC) waves onboard the ST-5 satellites in the topside ionosphere (heights from a few hundred up to thousands of km) are presented. In this project, three identical micro-satellites were located during three months in 2006 in almost identical orbits with distances between them from first thousands to hundreds of km. All ion-cyclotron wave packets detected by two-three probes were observed at crossing one and the same latitude, which manifests their narrow localization in latitude with a characteristic scale from the first tens to 100 km. In no event IC waves were recorded with comparable amplitudes by all three satellites. At the same time, in the case of ST-5 flight near the ground-based induction magnetometer, a long emission in the same frequency range on the ground corresponded to a burst of IC waves in the topside ionosphere. This can indicate to the fact that an IC instability develops not continuously, but in the pulsing regime with a characteristic time of up to ∼10 min. A change in the rotation direction when a satellite crosses the wave structure is a characteristic feature of the polarization structure of registered transverse waves. The detected effects are discussed from the point of view of the existing models of generation and waveguide propagation of IC waves. 相似文献
940.
M. Uetsuhara T. Hanada H. Yamaoka T. Yanagisawa H. Kurosaki Y. Kitazawa 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
This paper proposes a strategy to search fragments from breakups in the Geosynchronous Earth Orbit (GEO) region based upon population prediction and motion prediction by means of ground-based optical observations. Breakup fragments have uncertainties in the states such as their position and motion, or even in their existence. Population prediction and motion prediction resolve those uncertainties. Population prediction evaluates the time-averaged distribution of fragments, whose position at a given time is unknown, in the celestial sphere. Motion prediction evaluates the expected motion of fragments appeared in image series acquired by a telescope’s CCD camera. This paper logically describes procedures of the search strategy, and provides mathematical expressions of population prediction and motion prediction. This paper also validates the search strategy via actual observations, in which a confirmed breakup in the GEO region is selected as a target. It is concluded that the proposed strategy is valid even for searching uncataloged fragments from breakups in the GEO region. 相似文献