Description

This three-day course is designed as a practical course for practicing engineers, and is intended for communications engineers, spacecraft engineers, managers and technical professionals who want both the “big picture” and a fundamental understanding of satellite communications. The course is technically oriented and includes examples from real-world satellite communications systems. It will enable participants to understand the key drivers in satellite link design and to perform their own satellite link budget calculations. The course will especially appeal to those whose objective is to develop quantitative computational skills in addition to obtaining a qualitative familiarity with the basic concepts. 

What You Will Learn:

• A comprehensive understanding of satellite communication.
• An understanding of basic vocabulary.
• A quantitative knowledge of basic relationships.
• Ability to perform and verify link budget calculations.
• Ability to interact meaningfully with colleagues and independently evaluate system designs.
• A background to read the literature.

Course Outline:

1. Mission Analysis. Kepler’s laws. Circular and elliptical satellite orbits. Period of revolution. LEO, MEO, HEO, and Geostationary Orbits. Orbital elements. Azimuth and Elevation, slant range, coverage angle and ground trace
2. The RF Link – The Signal Antenna gain, effective isotropic radiated power, receive flux density and receive power, Friis link equation and variants. Review of deciBels (dB’s).
3. The RF Link – Noise fundamentals, noise temperature and noise figure of amplifiers, attenuators, and components. System noise temperature.
4. The RF Link – Putting it together Receive system G/T, received CNR, SNR. Bent-pipe and regenerative transponders, multiple carrier operation, noise power robbing and back-off.
5. Signals and Spectra Properties of a sinusoidal wave. Synthesis and analysis of an arbitrary waveform. Fourier Principle. Harmonics. Fourier series and Fourier transform. Frequency spectrum.
6. Methods of Modulation. Overview of modulation, frequency translation, sidebands, analog AM/FM modulation.
7. Digital Modulation. Nyquist sampling, analog-to-digital conversion, ISI, Nyquist pulse shaping, raised cosine filtering, BPSK, QPSK, MSK, 8PSK, QAM, GMSK, higher order modulation, bandwidth, power spectral density, constellation diagrams.
8. Demodulation and Bit Error Rate Coherent detection and carrier recovery, phase-locked loops, bit synchronizers, bit error probability, Eb/No, BPSK, QPSK detection, digital modulation performance.
9. Coding. Information theory basics, Shannon’s theorem, code rate, coding gain, Hamming, BCH, and Reed-Solomon block codes, convolutional codes, Viterbi decoding, hard and soft decision, concatenated coding, Trellis coding, Turbo codes, LDPC codes.
10. Bandwidth. Equivalent (noise) bandwidth. Occupied bandwidth. Allocated bandwidth. Relationship between bandwidth and data rate. Dependence of bandwidth on methods of modulation and coding. Tradeoff between bandwidth and power. Emerging trends for bandwidth efficient modulation.
11. Antennas. Directivity and gain, reciprocity, antenna patterns, beam solid angle, half-power beamwidth, nulls and sidelobes, efficiency, large apertures, antenna examples, shaped reflectors, phased-arrays.
12. Antenna Noise Temperature Brightness temperature, antenna noise temperature calculation and estimates, examples.
13. Polarization Linear, circular, elliptical polarization, axial ratio, handedness, interoperability, polarization mismatch loss.
14. Propagation Earth’s atmosphere, atmospheric attenuation, rain attenuation, rain models and variation with frequency, impact on G/T, system examples.
15. Earth Stations Antenna types, facilities, RF components, operations center.
16. Satellite Transponders Satellite communications payload architecture, frequency plan, transponder gain, TWTA and SSPA, amplifier characteristics, intermodulation products.
17. Multiple Access Techniques Frequency division multiple access (FDMA). Time division multiple access (TDMA). Code division multiple access (CDMA) or spread spectrum. Capacity estimates.
18. Link Budgets Communications link calculations, uplink, downlink, and composite performance, link budgets for single carrier and multiple carrier operation. Detailed worked examples.
19. Diversity Site, phase, frequency, time, polarization diversity techniques and system examples.
20. Navigation Range and range-rate (Doppler) tracking, GPS
21. VSATs Applications, access techniques, typical implementations.
22. Commercial and Military Satcomm System examples, GEO platforms, high throughput satellites, Iridium, Globalstar, Orbcomm, O3B, MILSATCOM, etc.
23. The Electromagnetic Spectrum. Frequency bands used for satellite communication. ITU regulations. Fixed Satellite Service. Direct Broadcast Service. Digital Audio Radio Service. Mobile Satellite Service.

Instructor(s):

Robert Summers has been developing space communication systems for more than 30 years, ranging from store-and-forward messaging by low Earth orbit satellites, to audio and video boadcasting from geosynchronous orbit, and voice and data communication constellations in between. He has been at the Johns Hopkins University Applied Physics Laboratory for the last 12 years, where he has been involved in numerous space system engineering activities. He has lectured in the JHU Whiting School of Engineering on system engineering topics, including telemetry, tracking and control (TT&C) subsystem communications that links the satellites to the ground systems. He has a BSEE from Stanford University and two MS degrees from Johns Hopkins, in computer science and technical management. For the April 28, 2020 Virtual Webinar Live Robert Summer will be your instructor.

Chris DeBoy leads the RF Engineering Group in the Space department at the Johns Hopkins University Applied Physics Laboratory, and is a member of APL’s Principal Professional Staff. He has over 25 years of experience in satellite communications, from systems engineering (he is the lead RF communications engineer for the New Horizons Mission to Pluto) to flight hardware design for both low- Earth orbit and deep-space missions. He holds a BSEE from Virginia Tech, a Master’s degree in Electrical Engineering from Johns Hopkins, and teaches the satellite communications course for the Johns Hopkins University.