Infrared Laser Satellite- Aircraft Communication

Transcription

1 Infrared Laser Satellite- Aircraft Communication Paul Christopher PFC Associates Leesburg, VA

2 Satellite-Aircraft Laser Communication Chu and Hogg laser attenuation vs wavelength Cloud attenuation from Barbaliscia s Italsat Solve GHz attenuation maps -and 49.5 GHz attenuation maps for cloud att n, and water vapor att n Show worldwide satellite- ground 10 micron att n Show satellite aircraft 10 micron att n - other IR wavelengths

3 Chu & Hogg s Attenuation v. Frequency, GHz db 50. fog Rain and Heavy Fog Att'n vs. Log(fGHz) Fig. 3-1 Chu and Hogg s Fog(top) and Rain Attenuation(dB) v. Frequency Note, 10u at 30,000 GHz and 1u at 300,000 GHz 10u rain 20. F,GHz

4 Massive 10 Micron Attenuation for Ground-Satellite NAECON 18

5 Ground Attenuation Relief with Quad Diversity, 100 km

6 Satellite-Aircraft Att n; 1,2,3 km Altitude

7 10 Micron Attenuation over N. America (2015) with 30% Cloud Cover. A 30% cloudless sky was assumed. a. 100 km Quad diversity b. 200 km c. 300 km Fig 1-1 Zenith Attenuation Estimates for Quad Diversity over North America 80% Reliability Thule db

8 Clear Sky Estimates for U.S as Function With Sunny Days= Mathematica Feb15 80pc90pc.nb

9 Att n at 80% Availability, 10 Microns Fig. 1-3 Ten Micron Zenith Attenuation (db) Estimate for U.S., 80% Availability

10 Higher Reliability with 10 Micron Links These conservative attenuation estimates are expected to offer even lower attenuation with closer estimation. Out[405]=,, Diversity, 200 km on a side 80%

11 Aircraft [2km]- Satellite 10Micron Att n

12 Low Att n Aircraft[3km]-Satellite, 10 Microns

13 Satellite-Aircraft Att n; 1,2,3 km Altitude

14 Aircraft- Satellite Att n at 0.5 km Increments

15 6 Micron Att n at ½ km increments

16 3 u Att n at 0.5 km Increments

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18 Compare Clear Skies in U.S., Europe Fig. 2-1 Compare Functional Estimates for Clear Atmosphere over the U.S and Europe Ju

19 Concluding Thoughts Satellite-Ground laser communication may be attractive -if modest 80% availability -if large scale ground diversity, as Takayama Satellite- Aircraft laser comm is attractive -for altitude>2km --both 10u, and 6u -especially on polar routes --with LEOS or Brandon Molniya

20 New Developments, Solar Impulse Flight Across U.S., Around World Bertrand Piccard and Swiss Research recognized Solar Power. They realized Solar Cells on the wing would offer good power. Strong, Rigid Wing Carbon Fiber Frame Wing Span like 747 Electric motors deliver 10 hp Piccard concepts will be attractive for Satellite Solar Arrays AFM 2015 pc

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25 Gerard O Neill s Solar Satellite Array Concept O Neill s offered many satellite concepts in the mid 70s His book High Frontier( 77) is available Large solar panels on Geosynchronous satellites Beam 2.2 GHz radio energy down to Large Ground receiver. Support faded when gas dropped, Ground Arrays limited. O Neill s health declined in the early 80s - A National Loss - and a NASA Loss

26 Would Satellite Solar Arrays Be Competitive? Warren Buffett investing 1.9 B in 656 wind turbines in Iowa. Would add 1050 megawatts power by May be interesting comparison for satellite solar arrays. -e.g., 1km square array => 1300 MW solar input - if 30% efficiency => 400 MW to Denver German research in satellite solar arrays - Expect test satellite launch by Jalali solid state silicon lasers promise reliable link to Ground - 10 micron solid state lasers appear feasible - Low atmospheric loss

27 Perovskite Complement to Jalali s Silicon Laser [Sci Am, July 2015]

28 Attractive Satellite Orbits for Solar Arrays Gerard O Neill favored Geostationary orbits -Stationary ground antennas for low cost Low Altitude, sun synchronous satellites -Perhaps (1/10) cost of Geostationary satellites -Solar Panels are perpendicular to Sun Vector -Active, difficult ground pointing. Brandon Molniya Orbits;GoodDownlinks to Denver,North -retains easy ground station pointing of Geos.

29 Geosynchronous Arc for Wide Range of Downlinks Mathematica Apr24GEO1.nb

30 Solar Array at GEO; Power Density on US, with 10m geo antenna at 3 GHz [as S Band] Mathematica Apr21 JiuxB.nb

31 Power Density with 30 GHz, 10m Antenna at GEO

32 A Chinese anti-satellite test in January 2007 left an enlarged debris field between centered near 800 km altitude. It stretches from 700 km to over 900 km altitud Sun Synchronous Orbits for Cost Effective Debris Field Solar Arrays EOS at 1200 km Debris Field at 800 km Fig. 2-1 ASAT Debris Field, Fig. 2-2 EOS Higher (1000km) than Mean Altitude 800 km. Debris Field Mathematica Apr27 EOScx.nb.

33 Sun Synchronous View at 701 km Inclination= 98.4 Deg.

34 Emphasize the Late W.T. Brandon s Concepts W.T. (Bill) Brandon observed key Molniya Features the 1970 s Noted excellent N Hemisphere visibility But Difficult/Expensive 3D Ground Tracking Bill observed key changes in Ease of Tracking(eccentricity) Sudden changes in tracking for.71< e <.73 E=0.722 for High Gain, single rotation axis antenna E= for High Gain, stationary antenna E=0.729 for Higher Gain, stationary antenna First, Bill was fascinated with Molniya Earth Views: +

35 Brandon Molniya Valuable for Northern Hemisphere Molniya at 1 hr Intervals Molniya seen from Ground Station Brandon Molniya 1 Hr Snaps Three Molniya Ground View Mathematica July508 C3.nb AFM 2015 pc

36 Compare 3D Views of Molniya; e=.64,.722 Compare e.722,.64 ; Molniya seen from Ground Station e= Hr e= Hr e= Hr, 10Hr e=.64 8 Hr 10 Hr AFM 2015 pc

37 Elevation PDF for Brandon4 Constellation + 2 Antipodal GEOs p E,Lat ;4Brandon Molniya 2 Geo sats pdf LAT El AFM 2015 pc

38 P ( E ) for Brandon4 Constellation searched exhaustively for elevation angles at all time and locations to yield a probability density function as: pdf [elev, LAT]= where LAT =latitude x=elevation ( 2-1) AFM 2015 pc

39 Sunspots and Temperature