AAE 450 – Senior Design

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AAE 450 Senior Design. J. Darcey Kuhn ERV Team Communications January 23, 2001. Parameters. High Gain Antenna Sizes Beamwidth and antenna gain Capacity (i.e. number of channels of each type) or bandwidths and frequencies - PowerPoint PPT Presentation

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  • AAE 450 Senior Design

    J. Darcey KuhnERV Team CommunicationsJanuary 23, 2001

  • ParametersHigh Gain Antenna Sizes Beamwidth and antenna gainCapacity (i.e. number of channels of each type) or bandwidths and frequenciesUplink & Downlink signal strength and quality to Deep Space Network (DSN) support communications, science data, voice, video, engineering telemetry, and navigationhttp://deepspace.jpl.nasa.gov/dsn/

  • High Gain AntennaBeamwidth: from an antenna pattern, the angle between the half-power (3 dB) points of the main lobe, when referenced to the peak effective radiated power of the main lobehttp://132.163.64.205/fs-1037/dir-004/_0572.htm

  • High Gain Antenna

    A useful rule of thumb for calculating beamwidth is 3 dB beamwidth = 70 / D (degrees)where is wavelength and D the antenna diameter

    Surveyor: 0.56 degSpace ShuttleUplinking: 0.56 degDownlinking: 0.51 deg

  • High Gain AntennaAntenna Gain (Isotropic) for a uniformly illuminated antenna with physical area A, the directive gain at the center of the main beam is given by:

    http://web.bham.ac.uk/eee1roj8/wbe/wbe031.htm

  • High Gain Antenna

    G = 4**A/2A= d2/4

    Gain is normally expressed in dBs by taking 10*log(G)Surveyor: 42.41 dBSpace Shuttle: Uplinking: 42.39 dBDownlinking: 43.14 dB

  • Bandwidths & FrequenciesBandwidth: Amount of data that can be transferred in a fixed amount of timeSpace Shuttle uses S-band (1,700 to 2,300 MHz) & Ku-band (15,250 to 17,250 MHz) to transfer informationKu-band located in the payload bayKu-band (12-18 GHz / = 2.5 to 1.67 cm) can handle higher quantities of data than the S-band systems (3 channels of data)All transmissions broadcasted by Surveyor utilized X-band radio signals near 8.4 GHz

  • Deep Space NetworkDSN is an international network of antennas that supports interplanetary spacecraft missionsCurrently consists of three deep-space communications facilities placed approximately 120 degrees apart around the world CA, Spain, and Australia

  • Antenna MountingHigh-gain antenna sits at the end of a long boomTwo rotating joints, called gimbals, hold antenna to boomGimbals will allow the antenna to automatically track and point at the Earth

  • Future Enhancementshttp://deepspace.jpl.nasa.gov/dsn/array/index.html

  • Future EnhancementsCost AnalysisPowerConsumptionSignalSignal-to-Noise RatioWeightHistorically lowFailure Probability Low Gain Antenna as back-up

  • Related Skills

    Matlab, Fortran 77, UNIX, AutoCAD, CCurrently enrolled in 490E (Satellite Systems)Two co-op tours with United Space Alliance at Johnson Space Center uplinking data from the MCC to ISS

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