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661.
L. Trafton 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(3):49-52
We have measured the amount of Raman scattering in Saturn's equatorial zone and polar regions near the central meridian at the wavelengths of the H and K Ca II solar lines, 3934 Å and 3969 Å. Approximately 2.1% of the sunlight in this wavelength range is Raman scattered out of this range in Saturn's equatorial zone. Modeling the aerosol particle distribution as a clear, Rayleigh- and Raman-scattering gas over a dense haze yields an H2 column abundance of about 40 km-Amagats. Comparison with results obtained by Pioneer 11 suggests that either the equatorial haze was 2.5 times deeper at the time of these observations (May, 1981) than at the time of the Pioneer 11 flyby (Sept., 1979); or the haze particles are much more strongly polarizing in blue light than they are in red light. 相似文献
662.
663.
The effect of modulation nonlinearity on the range response of FM radars with harmonic processing and ?triangle? modulation is derived. The nonlinearity may be desirable or undesirable; that is, the sidelobe level of the range response may be decreased or increased depending on the shape and amount of nonlinearity. The results of this paper may be used to predict the actual range laws of existing ?linear? FM radars; or, alternately, to specify the desired amount of modulation nonlinearity for new FM radars so that superior sidelobe suppression can be realized. 相似文献
664.
A detailed inaccuracy and sensitivity analysis of a long-distance air pollution detection system, using a laser measuring the resonance absorption of polluting molecules, is introduced. The noise and the dynamic range of the radiation detectors used, the atmospheric inhomogeneities, and the atmospheric propagation losses of the electromagnetic radiation are considered. In addition, the best measuring path length as a function of a molecule density and atmospheric transparency and irregularity is discussed. 相似文献
665.
The radar cross section of a flat plate has a sin x/x lobe structure. If a synthetic-array radar flies past the plate the resulting image is dependent upon what part of this lobe structure is sampled. When the plate is parallel to the flight path, the image is a line as wide as the plate. If the plate is not parallel, only the discontinuities at the ends of the plate are visible in the image. 相似文献
666.
Salinger S.N. Brandstatter J.J. 《IEEE transactions on aerospace and electronic systems》1970,(4):585-592
The techniques of recursive estimation and Kalman filtering are applied to the problem of estimation of space vehicle orbits and trajectories using only measurements of the Doppler shifts in radio signals transmitted by or reflected from the target. Two approaches are described. One is a global fit technique in which the parameters of an assumed trajectory model are estimated. The second is a pointwise mapping technique in which the trajectory estimate is extrapolated as the target tracking data is received. The paper provides a tutorial illustration of the direct application of recursive optimization techniques to a class of engineering problems. 相似文献
667.
668.
R.Z. Sagdeev G.G. Managadze A.A. Martinson Yu.A. Romanovsky R.I. Moisya W.K. Riedler M.F. Friedrich T.G. Adeishvily S.B. Lyakhov L.S. Novikov N.A. Leonov T.I. Gagua I.I. Slyusarenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):129-140
This paper describes two rocket experiments “Aelita” with high power lithium plasma injection. The results of onboard magnetometer, massspectrometer, photometer, plasma, corpuscular and ground radar measurements are given. Dynamics and structure of plasma formation are discussed. 相似文献
669.
The scattering effect of structures on Instrument Landing System localizer signals is analyzed in this paper. A generalized computer program results which can be used to determine the reflection from surfaces of most materials and orientations for which the radius of curvature is large compared with the wavelength. For most reflecting walls, a closed form solution is used and the computation time is short. The program will enable users to determine the placement of hangars, towers, etc., in airports and to find ways to reduce their effect on localizer facilities. 相似文献
670.
John S. Lewis 《Space Science Reviews》1973,14(3-4):401-411
Data on the composition of the satellites of the outer planets and the composition and structure of planetary atmospheres are briefly reviewed in light of simple models for the origin of the solar system and the planets. Some crucial tests of present theories are suggested.Contribution No. 52 of the MIT Planetary Astronomy Laboratory.This is one of the publications by the Science Advisory Group. 相似文献