http://www.ATIcourses.com/schedule.htmhttp://www.aticourses.com/Communications_Payload_Design_etc.htmlATI Course Schedule:...
www.ATIcourses.comBoost Your Skillswith On-Site CoursesTailored to Your NeedsThe Applied Technology Institute specializes ...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-2Objectives and Approach• Instructor:– Bruce Elbert, President, Application...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-3Course Outline• Comm Payloads and ServiceRequirements• Systems Engineering...
Satellite System DefinitionsVSATs orother userterminalsSpace segmentGround segmentTT&C earth stationSatellitecontrolcenter...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-5Kepler’s Laws of Planetary Motion• First Law: The orbit of each planet is ...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-6Earth Satellite Orbit OptionsOrbit definition Altitude range, km Period, h...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-7COPYRIGHT © 2000 • BRUCE R. ELBERTPlasma sheetPolar windPlasma spherePolar...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-8Radiation Dose vs. Altitude(5 mil Al thickness)0 2000 4000 6000 8000 10000...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-9Orbit Period and Delay vs. Altitude05101520250 10000 20000 30000 4000000.2...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-10LEO Constellation for Iridium• 66 satellites• 6 polar orbits• Inter-satel...
Iridium Spacecraft(Motorola and Lockheed-Martin)PD-1-01-11
PD-1-12http://www.faqs.org/sec-filings/100602/Iridium-Communications-Inc_8-K/dex992.htm
GEO Orbit “Slot” for Domestic ServiceCOPYRIGHT © 1999 – 2001 • BRUCE R. ELBERT• 24 hour orbit requires stationkeeping oper...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-14Antenna Beam OptionsArea Coverage Multiple Spot BeamsGWGWGWGWGWGW
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-15Star and Mesh TopologiesHubRemoteRemoteRemote RemoteRemoteRemotePeernodeP...
Large-capacity GEO SpacecraftPD-1-01-16Boeing 70215 kW4700 kg at launchSS/Loral 1300S19 kW6200 kg at launchEADS Astrium14 ...
Major Satellite Components• Payload subsystems– Repeater (receivers, multiplexers,amplifiers, processing and switching)– A...
Lockheed-Martin A2100 Three-Axis SpacecraftPD-1-01-18
Lockheed-Martin A2100 Block DiagramPD-1-01-19
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-20Typical Spacecraft Mass Allocation• Geostationary orbit• 15 year mission•...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-21Typical Spacecraft Power Allocation• GaAs solar cells• Flat solar panels•...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-22Satellite Size v. CapabilitiesHypotheticalclass of satelliteConceptualnum...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-23UHF L S C X Ku Ka Q V1 10 100 GHz0.1Microwave303Microwave Spectrum(log sc...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-24Totalattenuationtowardzenith, dBPropagation Effects onSatellite Systems a...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-25ITU-DAH Rain Model755537261425mm/hr, .01% of the time
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-26Elevation Angle DependenceRain Cell(rain rate)),,( FplrrfAplelel
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-27Rain Attenuation (temperate climate)Availability99.5%98.0%10°20°45°10°20°...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-28Typical Margin for Rain Fade (12 GHz)Rain Intensity Marginregion mm/hr at...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-29Rain Attenuation Solutions• Ku band (14/12 GHz)– Link margin» Satellite E...
Site (Space) DiversityDDPD-1-30
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-31Further Details on Propagation• Ionospheric effects (below 10 GHz)– Farad...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-32Maximum Ionospheric Effects[US one-way paths at 30 elevation, NASA 1108(...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-33Communication Payload Technology(Analog and Digital) Analog repeater– Be...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-34Analog (Bent-pipe) Repeater• Standard design for FSS and BSS satellites• ...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-35Frequency Plan for Bent Pipe Repeater1 2 3 4 5 6 7 81 2 3 4 5 6 7 8Uplink...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-36The Spacecraft Antenna System• Area coverage antenna– Most common approac...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-37Digital Signal ProcessingRepeater Design• Need for flexible payload archi...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-38Broadband Processing PayloadRcvfeednet-workTxfeednet-workRcvrRcvrRcvrRcvr...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-39Inmarsat-4 Global Coverage
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-40Course Outline• Comm Payloads and ServiceRequirements• Systems Engineerin...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-41The Microwave Link in SatelliteCommunications• Frequencies above 1 GHz (b...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-42Path Geometry (GEO Link) coscos29577.01107.42643 30 RR0hkmWhereR0 =...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-43Gain and Effective Area of a CircularAperturep...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-44Antenna “Capture” Area• Receive antenna “captures” power through its effe...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-45Polarization of the EM WaveLinear polarization:(a) vertical(b) horizontal...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-46Vertically polarized hornHorizontally polarized hornabWaveguide and Horn ...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-47Co and CrossPolarizationCo-polarizedsignal componentCross-polarizedsign...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-48Linear CrossPolarization IsolationCross-Polarization Isolation0102030405...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-49Properties of Circular Polarization• Special case of ellipticalpolarizati...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-50Polarization CouplingPolarization type Linear CircularLinear -10log [Cos2...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-51Depolarization in Rain (Ku – Ka)Cloud and Rain Cell Geometryaffect V and ...
COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-52Link Degradationhttp://descanso.jpl.nasa.gov/Propagation/1082/1082ch1.pdf
To learn more please attend this ATI coursehttp://www.aticourses.com/blog/Please post your comments and questions to our b...
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Communications Payload Design and Satellite System Architecture: Bent Pipe and Digital Processor-based Course Sampler

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This four-day course, ATI Courses.com's Communications Payload Design and Satellite System Architecture course , provides communications and satellite systems engineers and system architects with a comprehensive and accurate approach for the specification and detailed design of the communications payload and its integration into a satellite system. Both standard bent pipe repeaters and digital processors (on board and ground-based) are studied in depth, and optimized from the standpoint of maximizing throughput and coverage (single footprint and multi-beam). Applications in Fixed Satellite Service (C, X, Ku and Ka bands) and Mobile Satellite Service (L and S bands) are addressed as are the requirements of the associated ground segment for satellite control and the provision of services to end users.

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Communications Payload Design and Satellite System Architecture: Bent Pipe and Digital Processor-based Course Sampler

  1. 1. http://www.ATIcourses.com/schedule.htmhttp://www.aticourses.com/Communications_Payload_Design_etc.htmlATI Course Schedule:ATIs CONOPS:Satellite Communications Payload Designand System ArchitectureInstructor:Bruce Elbert
  2. 2. www.ATIcourses.comBoost Your Skillswith On-Site CoursesTailored to Your NeedsThe Applied Technology Institute specializes in training programs for technical professionals. Our courses keep youcurrent in the state-of-the-art technology that is essential to keep your company on the cutting edge in today’s highlycompetitive marketplace. Since 1984, ATI has earned the trust of training departments nationwide, and has presentedon-site training at the major Navy, Air Force and NASA centers, and for a large number of contractors. Our trainingincreases effectiveness and productivity. Learn from the proven best.For a Free On-Site Quote Visit Us At: http://www.ATIcourses.com/free_onsite_quote.aspFor Our Current Public Course Schedule Go To: http://www.ATIcourses.com/schedule.htm349 Berkshire DriveRiva, Maryland 21140Telephone 1-888-501-2100 / (410) 965-8805Fax (410) 956-5785Email: ATI@ATIcourses.com
  3. 3. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-2Objectives and Approach• Instructor:– Bruce Elbert, President, Application Technology Strategy, Inc.– Hughes Satellite, 1972 - 1999– BEE, City Univ. of NY, MSEE, Univ. of Md., MBA, Pepperdine Univ.– Contact: tel +1 (310) 918-1728, emailbruce@applicationstrategy.com• Objectives:– Develop a systems engineering approach for satellite communications– Explain the techniques and tools used to design commercialcommunications payloads– Provide the framework for the overall system and ground segment• Approach:– Blend the theoretical with the practical– Provide both the big picture and a detailed view– Interact and exchange concepts and methodologies
  4. 4. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-3Course Outline• Comm Payloads and ServiceRequirements• Systems Engineering toMeet Service Requirements• Bent-pipe Repeater Design• Spacecraft Antenna Designand Performance• Comm Payload PerformanceBudgeting• On-board Digital ProcessorTechnology• Multi-beam Antennas• RF Interference andSpectrum Management• Ground Segment Selectionand Optimization• Earth Station and UserTerminal Tradeoffs• Performance and CapacityAssessment• Satellite System VerificationMethodology
  5. 5. Satellite System DefinitionsVSATs orother userterminalsSpace segmentGround segmentTT&C earth stationSatellitecontrolcenterHub orgatewayearth stationCOPYRIGHT © 1997 • BRUCE R. ELBERT(satellite operator)(network operator or user)
  6. 6. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-5Kepler’s Laws of Planetary Motion• First Law: The orbit of each planet is an ellipse,with the Sun at one focus.• Second Law: The line joining the planet and theSun sweeps out equal areas in equal times.• Third Law: The square of the period of a planet isproportional to the cube of its mean distance fromthe Sun.vhP = 1.659 10-4 (6378 + h)3/2minutes
  7. 7. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-6Earth Satellite Orbit OptionsOrbit definition Altitude range, km Period, hrs• Low earth orbit (LEO) 150 - 1,000 1.5 - 1.8• Medium earth orbit (MEO) 5,000 - 10,000 3.5 - 6• Geosynchronous earth orbit 36,000 24– Inclined– Geostationary earth orbit (GEO)LEOMEOGEO
  8. 8. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-7COPYRIGHT © 2000 • BRUCE R. ELBERTPlasma sheetPolar windPlasma spherePolarcuspBow shockMagnetosheathMagnetopauseSolar windVan Allen BeltsSpace Environment
  9. 9. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-8Radiation Dose vs. Altitude(5 mil Al thickness)0 2000 4000 6000 8000 1000010103105107109Dose,Rads/yrAltitude, km
  10. 10. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-9Orbit Period and Delay vs. Altitude05101520250 10000 20000 30000 4000000.20.40.60.811.21.41.61.80 500 1000LEOAltitude, km Altitude, kmHours7.5 75 150 225 270Delay, ms
  11. 11. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-10LEO Constellation for Iridium• 66 satellites• 6 polar orbits• Inter-satellite links
  12. 12. Iridium Spacecraft(Motorola and Lockheed-Martin)PD-1-01-11
  13. 13. PD-1-12http://www.faqs.org/sec-filings/100602/Iridium-Communications-Inc_8-K/dex992.htm
  14. 14. GEO Orbit “Slot” for Domestic ServiceCOPYRIGHT © 1999 – 2001 • BRUCE R. ELBERT• 24 hour orbit requires stationkeeping operations– Maintain orbit in equatorial plane (N/S stationkeeping)– Compensate for east-west drift and eccentricity– Satellite service defined by antenna beam coverage• Lifetime determined by stationkeeping fuel reservePD-1-01-13
  15. 15. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-14Antenna Beam OptionsArea Coverage Multiple Spot BeamsGWGWGWGWGWGW
  16. 16. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-15Star and Mesh TopologiesHubRemoteRemoteRemote RemoteRemoteRemotePeernodePeernodePeernodePeernodeControlIn either topology, links can beestablished on demand or fixed
  17. 17. Large-capacity GEO SpacecraftPD-1-01-16Boeing 70215 kW4700 kg at launchSS/Loral 1300S19 kW6200 kg at launchEADS Astrium14 kW6000 kg at launchLM A 2100 AX3600 kg at launch
  18. 18. Major Satellite Components• Payload subsystems– Repeater (receivers, multiplexers,amplifiers, processing and switching)– Antennas (reflectors, feeds, feed networks,support structure and pointingmechanisms)• Bus subsystems– Tracking, telemetry, command and ranging(TTC&R)– Solar panels– Batteries– Reaction control system (propulsion)– Attitude and spacecraft control processing– Thermal control and structurePD-1-01-17
  19. 19. Lockheed-Martin A2100 Three-Axis SpacecraftPD-1-01-18
  20. 20. Lockheed-Martin A2100 Block DiagramPD-1-01-19
  21. 21. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-20Typical Spacecraft Mass Allocation• Geostationary orbit• 15 year mission• Three axis spacecraft• ~2000 kg total dry mass• ~8000 watts total (EOL)• Standard payload typeRepeater Antenna PowerTT&C ACS PropulsionThermal Structure Harness
  22. 22. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-21Typical Spacecraft Power Allocation• GaAs solar cells• Flat solar panels• NiH2 batteries• 15 year operation• ~8000 watts EOLRepeater TT&C ACSPropulsion Power Thermal
  23. 23. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-22Satellite Size v. CapabilitiesHypotheticalclass of satelliteConceptualnumber ofTranspondersGeneral Rangeof EOL PowerGeneral Rangeof LaunchMass, kg“Small” 24 to 36 4 to 6 kW 1500 to 2500“Medium” 48 to 72 8 to 10 kW 3000 to 4000“Large” 90 to 120 12 to 22 kW 4500 to 6000
  24. 24. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-23UHF L S C X Ku Ka Q V1 10 100 GHz0.1Microwave303Microwave Spectrum(log scale)
  25. 25. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-24Totalattenuationtowardzenith, dBPropagation Effects onSatellite Systems atFrequencies Below 10 GHz,NASA Publication 1108(02) 1987Frequency, GHzH2OO2O2 H20Clear Air Attenuationsinw0aa2a8AVariation of totalattenuation as afunction of elevationangle,  >10
  26. 26. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-25ITU-DAH Rain Model755537261425mm/hr, .01% of the time
  27. 27. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-26Elevation Angle DependenceRain Cell(rain rate)),,( FplrrfAplelel
  28. 28. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-27Rain Attenuation (temperate climate)Availability99.5%98.0%10°20°45°10°20°45°1 10 100Frequency, GHzElevationangle2 4 8 20 40 8050403020100Attenuation,dB
  29. 29. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-28Typical Margin for Rain Fade (12 GHz)Rain Intensity Marginregion mm/hr at 99.8%A 6 0.3B 12 0.5C 15 0.7D 19 0.9E 22 1.1F 28 1.4G 30 1.5H 32 1.7J 35 1.8K 42 2.2L 60 3.2M 63 3.4N 98 4.8P 145 5.8
  30. 30. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-29Rain Attenuation Solutions• Ku band (14/12 GHz)– Link margin» Satellite EIRP» Dish size– Uplink power control– Automatic Gain Control(AGC) in spacecraft– Antenna feed blower– Site selection (rain zone)• Ka band (30/20 GHz)– Link margin» Satellite EIRP• Spot beams• Dynamic power» Dish size– Uplink power control– AGC– Dynamic data/coding rate– Antenna feed blower– Radome– Site selection» Rain zone» Diversity• Site• Satellite
  31. 31. Site (Space) DiversityDDPD-1-30
  32. 32. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-31Further Details on Propagation• Ionospheric effects (below 10 GHz)– Faraday rotation of linear polarization – day to night variationgreatest during peaks of sun spot cycle– Ionospheric scintillation – most pronounced near the geomagneticequator (tropical regions) – frequency selective fading duringevening and morning transitions of the F layers• Tropospheric effects (low elevation angles)– Absorption– Scintillation– Ducting (Horizontal path)– Rain – ITU-R Dissanayake, Allnut, Haidara (DAH) model
  33. 33. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-32Maximum Ionospheric Effects[US one-way paths at 30 elevation, NASA 1108(2) Table 2.2]Effect 100MHz300MHz1 GHz 3 GHz 10 GHzFaradayrotation30rotations3.3rotations108° 12 1.1°Excesstimedelay25 s 2.8 s 0.25 s 28 ns 2.5 nsAbsorp(polar)5 dB 1.1 dB .05 dB .006 dB .0005 dBAbsorp(mid Lat)<1 dB .1 dB <.01 dB <.001 dB <.0001dBDisper .4 ps/Hz .015ps/Hs.0004ps/Hz.000015ps/Hz.0000004ps/Hz
  34. 34. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-33Communication Payload Technology(Analog and Digital) Analog repeater– Bent pipe (no change informat; uplink anddownlink noise combine)– Supports any modulationand multiple access– Limited routingcapability– Excellent dynamic range;impairments canaggregate Digital processing repeater– Channel routing or packetswitching– Tailored to multiple access(and modulation)– Separates uplink fromdownlink– Excellent routing (andswitching) capability– Limited dynamic range
  35. 35. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-34Analog (Bent-pipe) Repeater• Standard design for FSS and BSS satellites• Simple design, simple operation• Very flexible• Network optimization limitedWidebandreceiver(500 MHz bandwidth)F1 Pre A F1F3 Pre A F3F5 Pre A F5F6 Pre A F6F4 Pre A F4F2 Pre A F2LPF5.925-6.425 GHz3.7-4.2 GHz
  36. 36. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-35Frequency Plan for Bent Pipe Repeater1 2 3 4 5 6 7 81 2 3 4 5 6 7 8Uplink frequency rangeDownlink frequency rangeFup(low) Fup(hi)Fdwn(low) Fdwn(hi)Channel spacing Transponder bandwidthGuardbandNot to scale: guardband typically 10% of channel spacingTranslation frequency
  37. 37. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-36The Spacecraft Antenna System• Area coverage antenna– Most common approach for bent pipe repeaters– Coverage area is similar to local broadcasting (but with lessvariation of received signal power)• Coverage is defined by the antenna gain pattern
  38. 38. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-37Digital Signal ProcessingRepeater Design• Need for flexible payload architecture– Channel routing– On-demand reconfiguration– Demod/remod performance– Beam forming, multiple and flexible• Constraints– Signal structure (multiplex, modulation and multiple access)– Bandwidth– Processor speed and complexity– Power and weight– Impairments– Dynamic range
  39. 39. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-38Broadband Processing PayloadRcvfeednet-workTxfeednet-workRcvrRcvrRcvrRcvrRcvrRcvrHPAHPAHPAHPAHPAHPADigitalProcessor:A/DDemodRouting andSwitchingMultiplexingModulationBeam formingD/AReceivefeedsandapertureTransmitfeedsandapertureLow-power transmission line High-power transmission lineActive redundancy not shownUpconvor driverUpconvor driverUpconvor driverUpconvor driverUpconvor driverUpconvor driver
  40. 40. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-39Inmarsat-4 Global Coverage
  41. 41. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-40Course Outline• Comm Payloads and ServiceRequirements• Systems Engineering toMeet Service Requirements• Bent-pipe Repeater Design• Spacecraft Antenna Designand Performance• Comm Payload PerformanceBudgeting• On-board Digital ProcessorTechnology• Multi-beam Antennas• RF Interference andSpectrum Management• Ground Segment Selectionand Optimization• Earth Station and UserTerminal Tradeoffs• Performance and CapacityAssessment• Satellite System VerificationMethodology
  42. 42. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-41The Microwave Link in SatelliteCommunications• Frequencies above 1 GHz (but less than 60 GHz)• Line-of-sight propagation• Low received signal level due to large distancePrPtR02PrR0PtPowerFluxDensity,Watts/sq meterPrA= Pt4pR02
  43. 43. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-42Path Geometry (GEO Link) coscos29577.01107.42643 30 RR0hkmWhereR0 = slant range (distance between satellite and earth station)h = GEO altitude (35,788,293 meters) = Earth station latitude = Earth station relative longitude
  44. 44. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-43Gain and Effective Area of a CircularApertureppp44222GAADAGED
  45. 45. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-44Antenna “Capture” Area• Receive antenna “captures” power through its effective area• Transmit antenna is a reciprocal device (yielding the sameperformance as in receive)RPt AE222444pppRGPPGAAARPPrtrrEEtr
  46. 46. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-45Polarization of the EM WaveLinear polarization:(a) vertical(b) horizontalCircular polarization(c) Left hand(d) Right hand(d)λ
  47. 47. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-46Vertically polarized hornHorizontally polarized hornabWaveguide and Horn Polarization(Linear Polarization)c =2ab ~ a/2
  48. 48. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-47Co and CrossPolarizationCo-polarizedsignal componentCross-polarizedsignal componentRelative polarization angle, degreesRelativereceivedsignal0 10 20 30 40 50 60 70 80 901.00.90.80.70.60.50.40.30.20.10.0
  49. 49. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-48Linear CrossPolarization IsolationCross-Polarization Isolation01020304050600 1 2 3 4 5 6 7 8 9 10 11Feed offset angle, degreesIsolation,dB
  50. 50. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-49Properties of Circular Polarization• Special case of ellipticalpolarization• Polarization senseestablished within thetransmit feed system• Little or no impact from theIonosphere• Isolation propertiesgenerally inferior to linearAxial ratio = 20 log (a/b)
  51. 51. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-50Polarization CouplingPolarization type Linear CircularLinear -10log [Cos2] dB -3 dBCircular (elliptical) -3 dB GraphRef: Johnson, AntennaEngineering Handbook,FIG 23-7, p 23-9
  52. 52. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-51Depolarization in Rain (Ku – Ka)Cloud and Rain Cell Geometryaffect V and H polarizations differentlyCircular Polarization is composedof V and H polarizations
  53. 53. COPYRIGHT © 1999 - 2011 • BRUCE R. ELBERT PD-1-52Link Degradationhttp://descanso.jpl.nasa.gov/Propagation/1082/1082ch1.pdf
  54. 54. To learn more please attend this ATI coursehttp://www.aticourses.com/blog/Please post your comments and questions to our blog:Sign-up for ATIs monthly Course Schedule Updates :http://www.aticourses.com/email_signup_page.html

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