J. W. Warwick  J. B. Pearce  R. G. Peltzer  A. C. Riddle 《Space Science Reviews》1977,21(3):309-327

The planetary radio astronomy experiment will measure radio spectra of planetary emissions in the range 1.2 kHz to 40.5 MHz. These emissions result from wave-particle-plasma interactions in the magnetospheres and ionospheres of the planets. At Jupiter, they are strongly modulated by the Galilean satellite Io.As the spacecraft leave the Earth's vicinity, we will observe terrestrial kilometric radiation, and for the first time, determine its polarization (RH and LH power separately). At the giant planets, the source of radio emission at low frequencies is not understood, but will be defined through comparison of the radio emission data with other particles and fields experiments aboard Voyager, as well as with optical data. Since, for Jupiter, as for the Earth, the radio data quite probably relate to particle precipitation, and to magnetic field strength and orientation in the polar ionosphere, we hope to be able to elucidate some characteristics of Jupiter auroras.Together with the plasma wave experiment, and possibly several optical experiments, our data can demonstrate the existence of lightning on the giant planets and on the satellite Titan, should it exist. Finally, the Voyager missions occur near maximum of the sunspot cycle. Solar outburst types can be identified through the radio measurements; when the spacecraft are on the opposite side of the Sun from the Earth we can identify solar flare-related events otherwise invisible on the Earth.  相似文献   

  总被引：1，自引：0，他引：1  

Milleit  R.E. 《IEEE transactions on aerospace and electronic systems》1970,(1):73-78

The realization of a rectangular pulse-compression waveform having low time sidelobes and zero mismatch loss due to spectral weighting is discussed. The theoretical aspects of the design of such a waveform are presented with particular reference to frequency modulated, rectangular pulses. The design and performance of a matched-filter pulse-compression system having essentially zero mismatch loss are presented. The system discussed has a time-bandwidth product of 22 and time sidelobes suppressed at least 27 dB; the measured mismatch loss is 0.1 dB. The difficulty of achieving the required nonlinear time delay dispersion is overcome by synthesizing the dispersive network as a cascade of all-pass networks.  相似文献   

    

Nash  R.A. Hutchinson  C.E. 《IEEE transactions on aerospace and electronic systems》1973,(1):18-27

In order to stabilize the altitude calculation in an inertial navigation system, an altimeter is commonly used. In a conventional local-level mechanization, this is generally accomplished by correcting the vertical channel integrators with the difference between the inertial system and altimeter indication of vertical position. However, in a space-stable system the procedure is not as clear since a vertical channel is not physically present. Three altitude damping mechanizations for a space-stable inertial navigation system are proposed. The equivalent local-level mechanizations are then found by comparing error propagation equations in a common coordinate frame.  相似文献   

  总被引：2，自引：0，他引：2  

White  R.L. Adams  M.B. Geisler  E.G. Grant  F.D. 《IEEE transactions on aerospace and electronic systems》1975,(2):195-203

An extended Kalman filter is used to process line-of-sight measurements to stars and known landmarks providing a statistical indication of performance in estimating spacecraft attitude, orbital ephemeris, and the bias drift of a set of three strapdown gyros. The landmark measurements were assumed to have been taken from the imagery of an Earth-observing multispectral scanner. It is shown that filtering of these noisy measurements results in highly accurate estimates of the above parameters. Results are given showing the sensitivity of performance to various system parameters such as star tracker accuracy, errors in the knowledge of landmark position, and number of stars and landmarks processed.  相似文献   

    

Hollis  E.E. 《IEEE transactions on aerospace and electronic systems》1975,(1):115-118

A method of constructing digital phase reversal codes which have few nonzero sidelobes and which are available in frequent lengths is given. This is particularly important in the area of longer codes. The codes are a form of combined sequence and, hence, have the desirable property of bandwidth reduction for the outer code. However, only two member codes are required. A major usage of these codes may be in addressing.  相似文献   

    

Paulikas  G.A. Blake  J.B. Imamoto  S.S. 《IEEE transactions on aerospace and electronic systems》1975,(6):1138-1144

The Aerospace Corporation energetic electron-proton spectrometer operating on Applications Technology Satellite-6 (ATS-6) detects energetic electrons in four channels between 140 keV and greater than 32 MeV, and measures energetic protons in five energy channels between 2.3 and 80 MeV and energetic alpha particles in three channels between 9.4 and 94 MeV. After more than a year of operation in orbit, the experiment continues to return excellent data on the behavior of energetic magnetospheric electrons as well as information regarding the fluxes of solar protons and alpha particles.  相似文献   

    

R. E. Bourdeau 《Space Science Reviews》1963,1(4):683-728

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Steinberg  B.D. Yadin  E. 《IEEE transactions on aerospace and electronic systems》1983,(3):483-490

By distributing antenna elements or small subarrays throughout the skin of an aircraft, a large portion of the airframe can act as an electromagnetic transducer. The basic problem associated with such a design is that uncertainties in element locations due to the nonrigidness of the airframe induce phase errors. Self-cohering techniques are required to compensate for those errors. Four such techniques are presented here.  相似文献   

    

M R Sims  C T Pillinger  I P Wright  J Dowson  S Whitehead  A Wells  J E Spragg  G Fraser  L Richter  H Hamacher  A Johnstone  N P Meredith  C de la Nougerede  B Hancock  R Turner  S Peskett  A Brack  J Hobbs  M Newns  A Senior  M Humphries  H U Keller  N Thomas  J S Lingard  T C Ng 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,23(11):1925-1928

The aim of the proposed Beagle 2 small lander for ESA's 2003 Mars Express mission is to search for organic material on and below the surface of Mars and to study the inorganic chemistry and mineralogy of the landing site. The lander will have a total mass of 60kg including entry, descent, and landing system. Experiments will be deployed on the surface using a robotic arm. It will use a mechanical mole and grinder to obtain samples from below the surface, under rocks, and inside rocks. Sample analysis by a mass spectrometer will include isotopic analysis. An optical microscope, an X-ray spectrometer and a Mossbauer spectrometer will conduct in-situ rock studies.  相似文献   

    

L.M. Mukhin  D.F. Nenarokov  N.V. Porschnev  V.B. Bondarev  B.G. Gelman  G. Israe&#x;l  F. Raulin  J. Runavot  R. Thomas 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1987,7(12):329-335

SIGMA - 3 gas chromatograph on board VEGA 1 and 2 landing probes has been operated successfully in the 60 - 50 km altitude range, providing several in - situ chemical analysis of the gas and the aerosols of Venus cloud layers. Post flight calibration required to derive atmospheric abundancies from gas chromatograms were carried out using the SIGMA - 3 spare model. A Venus atmospheric aerosol simulation chamber was used in which sulfuric acid droplets were generated. Preliminary results of these calibration experiments indicate that the concentration of sulfuric acid in the upper part of the clouds ( 60 to 55 km) is about 1 mg/m³ and suggest that an additional constituant must be present in noticeable amount in the aerosols. From these experiments the mixing ratio upper limits of SO₂ is 100 ppmV and of H₂S and COS is few 10 ppmV.  相似文献