Satellite RF Communications and Onboard Processing Course Sampler

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Successful systems engineering requires a broad understanding of the important principles of modern satellite communications and onboard data processing. This course covers both theory and practice, with emphasis on the important system engineering principles, tradeoffs, and rules of thumb. The latest technologies are covered, including those needed for constellations of satellites.

This course is recommended for engineers and scientists interested in acquiring an understanding of satellite communications, command and telemetry, onboard computing, and tracking. Each participant will receive a complete set of notes.

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Satellite RF Communications and Onboard Processing Course Sampler

  1. 1. ATIs Satellite RF Communications and Onboard Processing course Instructors: Eric Hoffman Robert C. MooreATI Course Schedule: http://www.ATIcourses.com/schedule.htmATIs Satellite RF Communications: http://www.aticourses.com/satellite_rf_communications.htm
  2. 2. www.ATIcourses.comBoost Your Skills 349 Berkshire Drive Riva, Maryland 21140with On-Site Courses Telephone 1-888-501-2100 / (410) 965-8805Tailored to Your Needs Fax (410) 956-5785 Email: ATI@ATIcourses.comThe 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.htm
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  4. 4. Special Characteristics of Space LinksThe satellite is constantly moving -• Antennas must be constantly pointed• Doppler shift complicates receiver design Example: ∆f/f up to ± 25 ppm for LEO satellites (± 50 kHz at S-band).• Poor station coverage, short pass times – continuous coverage would require hundreds of ground stations – may need data storage – special communications orbits (geostationary, Molniya) – data relay satellite 3 EjH rj0424
  5. 5. The One-Way Radar Range Equation (3 Forms) PtGt A e r(GAIN-AREA) Pr = 4πR2 PtGtλ2Gr PtGtGr c2(GAIN-GAIN) Pr = = 4πR24π (4π)2R2 f2 Pt4πAe Ae PtAe Ae f2 t r t r(AREA-AREA) Pr = = λ24πR2 R2 c2 4 EjH yt0521
  6. 6. Typical Radiation Pattern of a High-gain Antenna ● ● ● 5 EjH yt0521
  7. 7. Helix Antennas for MSX and GPS Satellites 6 EjH yt0521 EjH yt1121
  8. 8. APL Hybrid Inflatable Antenna Source: APL Technical Digest, Jan ‘03 7 EjH ye0706
  9. 9. 8EjH yt0509
  10. 10. M-ary Phase Shift Keying (m = 8) For Pε small, Power Spectra 9EjH yn0822
  11. 11. Sun Noise 10EjH rj0422
  12. 12. Shannon’s Channel Capacity• Consider a channel with bandwidth W and signal-to-noise ratio S/N.• In 1948 Claude Shannon proved “there exist” codes and modulations which permit error-free communication, provided the bit rate does not exceed S C = W log2 ( 1 + ) N Claude Shannon• Do not use this upper bound for design! 1916-2001• By letting N = No W and W ∞, can show that error-free digital communication cannot take place below E/No = -1.6 dB (ln 2)• High performance exacts a price: bandwidth spreading, abrupt thresholds, complex coding/decoding equipment, computational delays 11 EjH ys0622
  13. 13. Prototype of Ball Aerospace’s TSAT laser comm terminal. Structure and all 3 mirrors made from SiC. 1.55 micron wavelength. Sat-to-sat at 40 Gbps.* 2.5 Gbps demo’d to aircraft. * transmit Encyclopedia Britannica in .025 sec 12 Ref: AW&ST 20 Nov 2006EjH ys1218
  14. 14. 13EjH yt1121
  15. 15. Supraluminal (faster-than-c) Communications • Can a particle be accelerated to c? • Can a particle have a velocity > c? - Tachyons: how generate, modulate, detect? • Wormholes. Spacewarps through higher dimensions. • Would supraluminal communications violate the Causality Principle? References: “Particles That Go Faster Than Light,” Gerald Feinberg, Sci. Amer., 222, 2, Feb. 1970 Tachyon, http://en.wikipedia.org/wiki/Tachyon Timescape, Gregory Benford, Simon & Schuster, 1980 A Brief History of Time, Steven W. Hawking, Bantam, 1988 “Faster than Light?” R. Y. Chiao et al, Sci Amer., Aug. 1993 Nine Crazy Ideas in Science, Robert Ehrlich, Princeton Univ. Press, 2001 14 “Time Travel,” Stephen Hawking, Discovery Channel, Apr 2010EjH ra1015
  16. 16. Satellite “Tracking”• Tracking: knowledge of satellite position and velocity (past, present, and future).• What are the tracking requirements and what drives them? – orbit insertion (“quick look” orbit determination) – precision orbit maintenance (e.g., 10 m) – ground station “alerts” – delayed commanding for future operations – processing of data post facto – satellite intercept and rendezvous – satellite avoidance – autonomous tracking required?• Orbit perturbations can limit the ability to predict the future or reconstruct the past. Perturbations may result from gravity harmonics, drag, radiation pressure, Sun and Moon, maneuvers, etc. Drag can be very unpredictable. 15 EjH gj0506
  17. 17. Typical NAVSPASUR Fan-beam Antenna 16 EjH xu0405
  18. 18. 17EjH gj0506
  19. 19. Maui Space Surveillance Site AtopMt. Haleakala (alt. 10,000 ft)Air Force Maui Optical Station (AMOS)Maui Optical Tracking and IdentificationFacility (MOTIF)Ground-based Electro-opticalSurveillance System (GEODSS) 18 EjH yt1120
  20. 20. Constellation DesignThings to think about . . . • Size of coverage circle • Dwell time over service area • Repeatability of ground track • Orbital perturbations • Van Allen radiation belts • Eclipse time • Launch energy required – altitude, inclination, eccentricity • Minimum number of satellites – how many planes? – how many satellites per plane? • Intra-sat comms and timing • Sparing and replacement 19 EjH yt1124
  21. 21. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic om a l te Encryption / Decryption Model3
  22. 22. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic om a l te End-to-End Command Flow4
  23. 23. AT M I AT w ate M I w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o SENSORS es D SELECTORS l• ACQUISITION w. N .c up CONVERTERS D CONDITIONERS AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er ia STORAGE AT Ic ot l• PROCESSING ou D FORMATTERS IM D COMPRESSORS at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic om a l te Spacecraft Telemetry System ANTENNA ENCODER MODULATOR5 TRANSMITTER TRANSMISSION
  24. 24. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Allan Deviation of Ic N M at ou ot rs D at e es up er ia .c lic om a l te Precision Frequency Standards6
  25. 25. e e at at lic l ia om lic up er .c up at D Telemetry Multiple Access es D IM ot rs ot N om AT ou N o Ic o D .c • AT l • D l ia es te l• er rs a ia w. a ic at • Frequency division multiple access (FDMA): different data on om er w ri ou pl M w ate .c at Ic u different sub-carrier frequencies TI D es M M •A AT ot rs TI • Time division multiple access (TDMA): a cyclic data frame is IAT w. N ou A om te defined in which different bit fields in the frame are assigned to w o Ic te • .c ca D te es li different users ca l• om a rs up .c lic ia w. li ou D w w up er es up • Code division multiple access (CDMA): coding techniques are used AT Ic ot at w D rs D AT N to avoid interference between different users. Each different coding M ot ou ot o N I Ic N algorithm is decoded using a separate decoder (e.g., ±90º, ±180º phase w. D AT o AT o w l• D shift; orthogonal binary pseudo-random modulations; frequency- D ia l• w. • er hopping) w al ia at w eri er w IM • Polarization division multiple access (PDMA): two signal sources at at IM AT IM use orthogonal polarizations of single carrier AT AT • Space division multiple access (SDMA): spot-beam antennas provide spatial separation of RF links March 2004 Command / Telemetry / Data Processing (Sampler) 7
  26. 26. AT M I AT w ate M I w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at Super-Commutation ou ot rs D at e Sub-Commutation and es up er ia .c lic l They are sub-commutated in three successive minor frames. om a te Data type 1 is super-commutated. It is sampled more than once in each minor frame. Data types 2a, 2b, and 2c are sampled less often.8
  27. 27. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot e Structure of a Typical rs D at es up er ia .c lic om a l te Packetized Telemetry Frame9
  28. 28. e e at at lic l ia om lic Structure of a Typical Real-Time up er .c up at D es D IM ot rs ot N Communications Bus Schedule om AT ou N o Ic o D .c • AT l • D l ia es te l• er rs a ia w. a ic at om er w ri ou pl M w ate .c at Ic u TI D es M M •A AT ot rs TI IAT w. N ou A om te w o Ic te • .c ca D te es li ca l• om a rs up .c lic ia w. li ou D w w up er es up AT Ic ot at w D rs D AT N M ot ou ot o N I Ic N w. D AT o AT o w l• D D ia l• w. • er w al ia at w eri er w IM at at 125 real-time slots, each 8 ms in duration IM AT IM Instrument short data: 256-byte packets, 13 Hz maximum AT AT Instrument long data: 1024-byte packets, 15 Hz maximum Instrument command: 250-byte packets, 15 Hz maximum RT reset (slot 58) occurs at 1/8 Hz (i.e., every 8 seconds) March 2004 Command / Telemetry / Data Processing (Sampler) 10
  29. 29. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia l• System IM ou D D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic l Spacecraft Data Processing om a te12
  30. 30. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic l Spacecraft Block Diagram om a te13
  31. 31. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) Block Diagram of Ic N TI lic ou ot M at e rs D at Error-Correcting Logic es up er ia .c lic om a l te14
  32. 32. e e at at lic l ia om lic Earth-Orbit up er .c up at D es D IM ot rs ot N Radiation Environment om AT ou N o Ic o D .c • AT l • D l ia es te l• er rs a ia • Low altitude (200 – 500 km), low inclination (i ≤ 28°) w. a ic at om er w ri ou pl M w ate .c at – 100 – 1k rad(Si)/year. Design to 10k rad(Si)/year. Incident charged Ic u TI D es M M particles, Van Allen Belts, make SEUs an important concern at low •A AT ot rs TI I inclination.AT w. N ou A om te w o Ic te • • Low altitude (200 – 1000 km), high inclination (i > 28°) .c ca D te es li ca l• – 1k – 10k rad(Si)/year. Design to 100k rad(Si)/year. More protons from om a rs up .c lic ia w. li ou D Van Allen Belts, so use Adams ten percent worst case environment for w w up er es up AT Ic ot SEU calculations. at w D rs D AT N M ot ou ot • Medium altitude (1000 – 4000 km) o N I Ic N w. D AT – 100k – 1M rad(Si)/year. Design to 1M rad(Si)/year. Almost no o AT o w l• D D ia geomagnetic shielding. Must use the most radiation-tolerant parts l• w. • er available. w al ia at w eri er w IM • High altitude (> 5000 km); e.g., geosynchronous (36,000 km) at at IM AT IM – 1k – 5k rad(Si)/year. Design to 50k rad(Si)/year. Spacecraft charging AT occurs as Earth’s magnetic field interacts with Solar wind, so SEU AT effects are dominated by the Adams ten-percent worst-case environment. March 2004 Command / Telemetry / Data Processing (Sampler) 15
  33. 33. AT M I w ate AT M w ri I AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at Systems (Box-level) ou ot rs D at e es up er ia .c lic om a l Cross-Strapping Redundant te16 No single-point failure should be able to drag down both sides!
  34. 34. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic om a l te Hot Tips for Flight Software17
  35. 35. AT IM AT w ate I M w ri AT at w. a er AT l • DMarch 2004 IM ia Ic o at l• ou N er w D rs ot ia w o es D l• w. N .c up D AT ot o Ic u D om lic N ou pl at e ot ic w D rs a es te AT w up w. li ca .c • IM AT om AT at Ic te • IM er ou A at w ia rs TI er w l• es M ia w. D .c at l AT N o om er AT Ic ot ia Hybrid IM ou D l• D at rs up o w eri es li .c ca N w al ot w. • om te D AT o D •A upCommand / Telemetry / Data Processing (Sampler) TI lic Ic N M at ou ot rs D at e es up er ia .c lic om a l te Image Compression Algorithm18
  36. 36. You have enjoyed an ATIs preview ofSatellite RF Communications and Onboard Processing Please post your comments and questions to our blog: http://www.aticourses.com/blog/index.php Sign-up for ATIs monthly Course Schedule Updates : http://www.aticourses.com/email_signup_page.html

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