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961.
Edward J. Rhodes Alessandro Cacciani Steven Tomczyk Roger K. Ulrich Jacques Blamont Robert F. Howard Philip Dumont Edward J. Smith 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(8):103-112
A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-ω power spectra which show clear- the solar nonradial p-mode oscillations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission. 相似文献
962.
Convergence results for a mean level adaptive detector (MLAD) are presented. The MLAD consists of an adaptive matched filter (for spatially correlated inputs) followed by a mean level detector (MLD). The optimal weights of the adaptive matched filter are estimated from one batch of data and applied to a statistically independent batch of nonconcurrent data. The threshold of the MLD is determined from the resultant data. Thereafter a candidate cell is compared against this threshold. Probabilities of false alarm and detection are derived as a function of the threshold factor, the order of the matched filter, the number of independent samples per channel used to calculate the adaptive matched filter weights, the number of samples used to set the MLD threshold, and the output signal-to-noise power ratio of the optimal matched filter. A number of performance curves are shown and discussed 相似文献
963.
I.M. Golinskaya A.B. Diachkov V.G. Kurt T.A. Miziakina A.S. Smirnov V.M. Shamolin E.Yu. Shafer E.K. Sheffer 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
This paper describes the X-ray instrumentation, its capabilities and preliminary results which have been obtained for first two months operation. 相似文献
964.
Pattipati K.R. Kurien T. Lee R.-T. Luh P.B. 《IEEE transactions on aerospace and electronic systems》1990,26(5):774-791
The problem of mapping the tasks of a multitarget tracking algorithm onto parallel computing architectures to maximize speedup is considered. An asymptotically optimal mapping algorithm is developed and applied to study the effects of task granularity and processor architectures on the speedup. From the simulation results, it is concluded that task granularity and the parallelization of clustering and global hypotheses formation stages of the tracking algorithm are major determinants of speedup 相似文献
965.
A systematic reliability analysis procedure for evaluating fault-tolerant inertial measurement unit (IMU) architectures is described. The procedure is based on modeling the system architecture, the component reliabilities, and the redundancy management. The component reliabilities are based on constant failure rates and exponential failure distributions. The overall reliability of the IMU and the major contributors to IMU reliability are computed. Three state-of-the-art fault-tolerant IMU architectures are evaluated and compared using the procedure 相似文献
966.
K. Labitzke B. Naujokat J. J. Barnett 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1990,10(12):163-184
The new Reference Atmosphere presented here is based on global satellite data and forms a very useful basis for climatological studies. When using such climatologies it is important to be aware of the well known interannual variability which in the middle atmosphere is particularly large during the northern winters and southern springs. 相似文献
967.
C.R. Philbrick K.U. Grossmann R. Hennig G. Lange D. Offermann D. Krankowsky F.J. Schmidlin U. von Zahn 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(10):121-124
During the Energy Budget Campaign, several profiles of the density and temperature of the upper atmosphere were obtained. The measurements were made using rocket-borne instrumentation launched from ESRANGE, Sweden and Andoya Rocket Range, Norway during November and December, 1980. The techniques included meteorological temperature sondes, passive falling spheres, accelerometer instrumented falling spheres, density gauges, mass spectrometers and infrared emission experiments. The instruments provided data within the altitude range from 20 km to 150 km. The measurements were made during periods which have been grouped into three categories by level of geomagnetic activity. Analysis has been made to compare the results and to examine the oscillations and fluctuations in the vertical profiles for scales ranging between hundreds of meters and tens of kilometers. Most of the features observed fit qualitatively within the range expected for internal gravity waves. The geomagnetic storm conditions may be associated with enhanced wave activity and heating observed in the lower thermosphere. 相似文献
968.
Radio bursts in the frequency range 100–1500 kHz and fluxes of energetic electrons with energies of 20–450 keV recorded onboard the Interball-1 satellite during prominent chromospheric flares on the Sun are studied. The time of propagation of the electrons to the Earth is estimated using the method of comparison of the moments of the beginning of radio emission generation during the explosive phase of the flare and the arrival of the accelerated electrons to the Earth. 相似文献
969.
D E Page E J Smith K P Wenzel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):611-618
Proton fluxes obtained by two instruments carried on the ESA/NASA Ulysses spacecraft are reported for the period from launch in October 1990 till Jupiter encounter in February 1992. Proton energy ranges are 24-59, 71-99, 130-320, 320-2100 and > 2100 MeV. The Sun was very active during this period, the events of March 1991 being some of the largest of the solar cycle. The relationship between events on the Sun and the observed proton flux is discussed. 相似文献
970.
E G Mullen K P Ray 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):797-807
A MicroElectronics Test Package (MEP) measured total dose degradation and single event upsets (SEUs) on 60 device types on the Combined Release and Radiation Effects Satellite (CRRES) in an 18 degrees inclination orbit between 350 km and 36000 km from July 1990 to October 1991. Simultaneous measurements of the high energy particle environment were used to make a direct cause and effect comparison of the energetic particle backgrounds and microelectronic performance characteristics. The galactic cosmic ray background for the period of the CRRES mission was at a minimum. The SEUs experienced from the cosmic ray background were correspondingly few in number, but surprisingly produced an equal probability of upset over an L-shell range of 8.5 Earth radii (RE) down to less than 3.0 RE. Cosmic ray induced upset frequencies in proton sensitive chips were over 2 orders of magnitude lower than those produced by protons in the heart of the inner proton radiation belts. Multiple upsets, those produced when a single particle upsets more than one memory location, were just as common from protons as from cosmic rays. 相似文献