Basic Satellite Communication 5 Ground Segment and Practical

Basic Satellite Communication (5) Ground Segment and Practical Aspects of Sat. Com Dr. Joseph N. Pelton

Typical VSAT System Applications (Very Small Aperture Terminals) • Credit Card Validation • ATM/Pay at the Pump • Inventory Control • Store Monitoring • Electronic Pricing • Training Videos • In-Store Audio • Broadband Internet Access • Distance Learning Apartment Buildings Corporate Offices Residential Gas Stations Branch offices Corporate Data Center

Key Trends for Satellite and User Terminals Satellite in general are becoming more capable, with higher power and larger aperture antennas to promote frequency re-use and higher flux density. Thus satellites are increasingly massive (due to antenna and power systems) but are, in essence, highly capable “super-computers-in-the-sky” with specialized digital software. l This allows user terminals to become smaller, lighter in weight and still handle broader band services. This is sometimes called technology inversion. Overall systems costs have decreased because of the explosion of low cost user terminals that can now receive video via hand-held units. l User terminals with Geo-systems do not have to be re-pointed, but LEO or MEO-systems must be able to track or have omni (or quasi-omni) antennas so that signals can be received from all possible angles. l

Key in User Terminals l Growth in VSATs towards 1 million with virtually all of them optimized via new IP over Satellite (IPo. S) standard. l Size of VSATs has decreased from around 3 meters down to about 1 to 1. 2 meters and costs have continued to decline especially driven by Digital Video Broadcast and DOCSIS standards that allow very high speed low cost links (i. e. 45 to 60 Mbps) with return channel service (RCS) that allows up stream speeds in the 56 to 384 kbps range.

Ground Equipment Trends Terminals Omni directional or “patch” antennas l Smaller, lighter, cheaper l Yet more capable (i. e. video signals & broadband) l Pocket, notebook, rugged l Sophisticated (ASIC driven) yet simple l Application specific terminals, embedded modems Phones l Satellite capability + 3 GSM frequencies + “video” l Voice, Asynchronous Data and Packet Data l Smaller (antenna and battery in particular) l Long stand-by mode Minimal Set-Up Time, Robust, Portable, Easy to Use l

Rural – Hybrid Networks l Internet backbone distribution using satellite – local distribution using 2. 4 GHz wireless

Satellite-Fiber Comparison Comparing Satellite and Fiber Characteristics Capability Fiber Optic Cable Systems Geo Satellite in Meo Satellite in a Global System Leo Satellite in a Global System Transmission Speed 10 Gbps – 3. 2 Terabits/second* Single Sat 1 Gbps -10 Gbps Single Sat 0. 5 Gbps-5 Gbps Single Sat. 01 Gbps-2 Gbps Quality of Service 10 -11 - 10 -12 10 -2 - 10 -11 Transmission latency 25 to 50 ms 250 ms 100 -150 ms 25 -75 ms System Availability w/o Backup 93 to 99. 5% 99. 98% (C-Ku band) 99% (Ka band) 99. 9% (C-Ku band) 99% (Ka band) 99. 5% (L-C-Ku band) 99% (Ka band) Broadcasting Capabilities Low to Nil High Low Multicasting Capabilities Low High Medium Trunking Capabilities Very High Medium Low Mobile Services Nil Medium-to-High

Dramatic decrease in the cost of Fiber Optic Systems lifetime 1995

Satellite Based IP Services Growing Demand for all types of IP based satellite services is growing including Vo. IP and MMIP. l Satellite service today requires special “spoofing” systems to achieve reasonable transmission efficiency (85% + possible with the best system from Mentat, Via. Sat, etc. and use of the new IPo. S standards. l Improvements can be achieved by increasing window sizes to reduce misinterpretation of latency for system congestion, spoofing software, and other modifications to satellites to address IP Security issues. l

Satellite Lifecycle and Failure Modes l l l Most failures occur at start or end of life Many satellite failures are due to software or operator errors rather than hardware failures Infant Failures (deployment of antenna and solar arrays, failure to reach proper orbit, etc. ) End-of-Life Failures and Wear-out (MTTF) Bathtub Curve of Satellite Failures Catastrophic Failures can occur at any time. (Orbital debris, Electro-Magnetic Storms, Cosmic Rays, Micro-meteorites, etc. )

Satellite Employment Patterns 1998 -2004 (97, 000 to 162, 000) 190, 00 0 170, 00 0 150, 00 0 Launch Vehicle Manufacturing of Experimental Sat. Com Satellite Manufacturing 130, 00 0 Ground Equipment Manufacturing 110, 00 0 Satellite Services 105, 00 0 100, 00 0 1998 1999 2000 2001 2002

Satellite Technologies of the Future l On-Board Processing l Signal Regeneration l Advanced Antenna Systems (hopping/scanning beams, phased-array, inflatable structures, piezo-electric systems) l More Efficient Power Systems l Turbo-coding l Advanced Modems and Enhanced Vocoder Algorithms and Error Correction Systems

Satellite Technologies of the Future l More Efficient Use of Spectrum l New Materials for Light Weight Antennas and Satellite Construction l Advanced Orientation and Propulsion Systems (and Autonomous Operation) l Advances in Launch Systems l USATs, VSATs, Micro-terminals (MEMS & ASIC break-throughs)

Course Review l Satellite Services and Markets (Overview) l Development of Satellite Technology from the 1960 s onward l Basic Elements of Satellite Transmission l Satellite Orbits (Pros and Cons) l Satellite Frequencies and Spectrum Allocation l Key Satellite Terms & Concepts

Assignment l Assignment 6: – Write short notes on the terms highlighted in yellow color