Satellite telephones
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16-09-2009, 11:59 PM


Satellite telephones
there are confirmed reports that terrorists involved in Mumbai blast used sat phones for communication. Most of us are not familiar with satellite telephones. It comes to daily use for those who work in ship, military, disaster management, etc. Most mobile telephone networks operate close to capacity during normal times, and during emergency situations due to large call volumes, the telephone systems get overloaded. Satellite telephones are of use when we need congestion free, portable means of communication. A satellite phone, or sat phone, uses a network different from that of normal mobile phones. These do not use transmitting towers, but makes use of satellites directly. A number of technical challenges are involved in devising a satellite phone system. Path length between earth and satellite introduces significant losses due to divergence. To minimize this, most of the systems use low earth orbiting satellites. But then, a number of satellites are to be used; each satellite will be in view only for a certain amount of time. It is therefore necessary even for a stationary phone to be able to change over from one satellite to another. There are service providers who make use of geostationary satellites as well like Aces, Inmarsat , Thuraya and MSAT. Phones used for satellite communication are often larger in size. The antenna is often larger to ensure the required level of power. Any mobile phone requires speedy communication with the network to enable calls to be set up, controlled and finished. The round trip delay from the mobile to satellite and back to the earth is significantly long, and affects speed of communication and protocol exchanges. As a result, much of intelligence of the system has to be placed within the satellite so that the required protocol exchanges can take place fast. A satellite phone doesnâ„¢t rely on local telephone infrastructure to function. Because of this, they are used widely in regions which are disaster prone. Satellite phones are used widely in ships for communication. They are also used widely for communication in remote area where there are no mobile networks available. There are many disadvantages; high cost of both the handset and call, and bulky handset are some. Satellite phone networks themselves are prone to congestion as satellites cover a very large area with relatively less number of voice channels. Sat phones are built for one particular network and cannot be switched to other networks for dedicated and critical channels, satellite phones are very effective. While popularizing more efficient and strategic technologies, government and people must make sure that they donâ„¢t reach wrong hands. There are confirmed reports that terrorists involved in Mumbai blast used sat phones for communication
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SATELLITE PHONES
ABSTRACT
SATELLITE PHONES
1. Satellite Phone
Satellite phone enables you talk to anybody from anywhere in the world. A number of compacting Mobile Satellite Services (MSS) plan to blanket in globe with satellite phone coverage from a constellation of over 1,000 satellite by 2004.These system include Iridium, Global star, Odyssey, Teledesic, ICO, Thuyra etc 2.Major Applications
> In Ships
> In aero planes
> In Military
> In Business
3.Major Satellite Phone Services
Iridium and Global star are the major two companies, which give the service of satellite phones. 4.1ridium
Motorola established the Iridium Company in 1990. Iridium satellite service provides coverage across all ocean area ,air routes and all land masses including poles.
Iridium System is comprised of three principle components
1 .Satellite Network
2.Ground Network
3.Iridium Subscriber Products. 5.Iridium Handsets
> Iridium 9505A
> Iridium 9005
> Iridium 9500 etc 6.GlobaI Star
In the field of satellite phones Global Star has Second Place. Major difference between Iridium and Global Star is that it uses only two satellite (One satellite at calling place and the receiving place). The other communication is by ordinary phone network. 7.Global Star Handsets
> GSP2900
> FAU200
> GSP1600
8.Other topics
> Advantage and Disadvantages of Satellite Phones
> History of Iridium
> Communication paths with figures
> Overview of different satellite Phones etc
INTRODUCTION
1.1 What is satellite phone
A Satellite phone is a phone, which uses satellite for communication. Satellite phone enables you talk to anybody from anywhere in the world. A number of competing Mobile Satellite Services (MSS) plan to blanket the globe with satellite phone coverage from a constellation of over 1,000 satellites by 2004. It has great advantages over ordinary mobile phones.
1.2 Why satellite phones have been developed
As developments in business, travel and technology have led to the increased human exploration of such 'remote and wild corners', the demand for a system of communication, beyond that of cellular phones, has arisen. It is for this reason that satellite technology has been developed.
1.3 Advantages
Satellite phones have the following advantages over ordinary mobile phones.
1. No problem related with coverage:-The great disadvantage of the mobile phone is that lack of coverage area. But this problem does not arise in satellite phones.
2. Uniformity in number:-\x\ ordinary phones, there is change of number when the customer moving from one state to another or one nation to another. But in satellite phones the number is same everywhere in any part of the world.
3. No STD/ISD code:-\x\ satellite phones service, there are no STD/ISD codes.
4. Uniform performance:-\n ordinary mobile service, if the mobile tower at a large distance from the phone, the signal will not be clear and communication is not so good. But in satellite phones this problem does not occur.
5. Facilities: -All facilities in the ordinary phones like vibrator, address book, ring
tones etc also available in the satellite phones also.
1.4 Disadvantages
Satellite phones are not common today because of the following disadvantages as compared to ordinary mobile phones.
1. Cost :-The cost of the phone is high as compared to ordinary phones. The cost varies from one phone to another.
2. High calling cost .'-Satellite phones have high calling cost.
3. Size:-\l has large size
4. Antenna size :-The size of the antenna attached to the satellite phone is high.
1.5 Applications
The major applications of satellite phones are in
1. Marine Engineering (Ship etc)
2. Aviation (aero planes etc)
3. Business field
4. Disaster Relief organizations etc.
1.6 Satellite phone services
The most popular organizations that give satellite phone services are
1. Iridium
2. Globalstar
3. Inmarsat
4. Thuraya
5. Odyssey
6. Teledecic etc.
Three satellite systems that have gained wide spread popularity are Iridium, Globalstar and Inmarsat
IRIDIUM SATELLITE SERVICE
The Iridium System is a satellite-based, wireless personal communications network providing a robust suite of voice and data services to virtually any destination anywhere on earth.
Motorola established iridium in 1960. Initially the aim was to use 77 satellites for communication. So the name iridium comes. (Iridium is the 77lh element in the periodic table). But later it was planned to use 66 satellites. In 1997, Iridium starts its service by using 66 satellites. But at that time, because of propagation of mobile phones and also the high cost of satellite phones, Iridium would not get the customers. But later in 2001,it start's its service and now it have a good position in satellite communication service.
2.1 Satellites in Iridium Service
The 66 satellites for iridium service circles around the earth along the low earth orbit (LEO). The satellites are about 750 Km away from the earth surface. It completes its motion around the earth in each 6 hours.
Since the satellites are in LEO, the signal delay for communication is very low. Also it has also some advantage is that only a small power is required for transmission and reception of data's. Also the size of the phones can be reduced.
The communication between satellite and phone (or gateways) is through L band (1616MHz) and the communication between two satellites is by using Ka band (19GHz).
Satellite A
Satellite B
Kn Band(19GH7)
\
I ..Unnil(lKlhMM/)
I H(in()(lhlhMII/)
Satellite phone A figl :Frequency bands for communication
Satellite phone B
fig 3 : Coverge of a iridium satellite
2.2 Iridium communication Network
Iridium communication system composed of 3 major parts. They are.
1. Satellite Network
2. Ground Network
3. Iridium Subscriber products Bach can be described as follows
1. Satellite Network
As stated earlier, satellite network consist of 66 satellites circles around the earth along LEO. Each satellite traveling at 16,832 miles per hour, each satellite is able to circle the globe every 100 minutes. This satellite acts as cellular towers in the sky.
Iridium subscriber product (Phone)
Ground Network
Iridium Satellite
Fig 5 :Iridium communication network diagram
Satellite Phones ^NO
liitiBRARYfell
2.Ground Network
The ground Network means different iridium gateways. Iridium gateways interconnect the iridium constellation with public switched telephone network, making communication possible between iridium phones and any other telephone in the world.
3.Iridium subscriber products It includes iridium phones, pagers etc.
Iridium phones: The iridium phone is the primary means by which callers will communicate directly through the iridium network by the use of Subscriber Identity Module (SIM).
Iridium Pagers! Iridium pagers are capable of receiving alphanumeric messages.
2.3 Iridium Voice Services
If you work, live or travel in areas outside cellular coverage or in areas with inadequate landline service, Iridium is for you. Eighty-six percent of the world's land mass and all of its oceans are in areas with inadequate landline service. Iridium addresses these situations by providing coverage in all ocean areas, air routes and all land masses The Iridium system provides true global voice services by covering areas that cellular and landline do not. Voice services are supported using the 9500 handset or the smaller, lighter 9505 handset. The excellent signal strength provided by the Iridium constellation supports reliable connectivity across wide ranging landscapes and situations.
Iridium offers a number of other great features such as:
> Call Forwarding
> Personal mailbox that receives and stores numeric messages, text messages, and voice mail messages.
^ Voice mail allows callers to leave a recorded message in your personal mailbox.
Dcpt.ofECE,S.KG.C.E
-6-
2.4 Iridium Coverage Map
Figure 6 below shows coverage map.
Fig 6:Iridium coverage Map
From this figure it is clear that Iridium Satellite Solutions global service provides coverage across all ocean areas, air routes, and all land masses, even the Poles. A host of Iridium Satellite Solutions equipment options exist to meet your specific fixed-site and mobile communications needs.
3
GLOBALSTAR SATELLITE SERVICE
Globalstar service has also a great position in satellite phone service. It uses 48 satellites for communication. Globalstar provides a high quality, affordable and reliable satellite communication.
Globalstar satellite telephone service is delivered through special multi-mode phones, which work just like traditional cellular phones when you are in an area with cellular coverage. When you need to communicate from outside the area covered by ground-based systems, the phones easily switch to Globalstar satellite mode. Satellite and cellular communications are both at your fingertips.
3.1 Globalstar communication
Globalstar satellite phone service is delivered thought 48 Low-Earth-Orbiting Satellites providing both voice and data services. The Globalstar LEO constellation is only 700 miles from earth, which allows for the highest quality voice clarity of any satellite phone in the industry.
QualComm's Code Division Multiple Access or (CDMA) technology is the basis of the Globalstar's digital satellite service. This technology allows for signal security, superior quality, fewer dropped calls, and greater reliability.
Globalstar uses redundancy with every call a customer places. A call is routed through as many as four satellites, which then combine the signal into a single static free call. If one of the paths to one of the satellites is blocked the other satellites keep the call from terminating. This is called (Path Diversity) which minimizes dropped calls and enhances the quality of the Globalstar satellite phone service.
Globalstar's (Bent-Pipe Technology) allow the call to be first beamed up to the satellite and then retransmitted to a relatively close gateway. The call is then sent through to its call destination through land-line or cellular networks. The Globalstar Gateway carries out all the processing and switching of the calls rather than the satellite itself. This
improves the reliability of the call delivery (Fig 7)
3.2 Advantages
Following are the advantages of Globalstar communication
1 .Multimode Operation: It can be work in both the cellular mode and the satellite mode. Some Globalstar phones automatically switched to cellular mode when the phone is in cellular range and it is switched to satellite mode when the phone is out of cellular coverage.
2.Reduced Call COSt'. Since there is multimode operation, the cost of calling is reduced.
3.It provides Internet servicing, paging etc
4.Gobalstar communication is reliable
4.It is a high quality satellite-based telephony service.
3.3 Disadvantages
The major disadvantage of Globalstar communication is limited coverage area .Its service is about 100 countries only.
& Globalstar Gateway [j Primary Globalstar Service Area Extended Globalstar Service Area
(Customers may have single satellite coverage and experience a weaker signal)
§B Fringe Globalstar Service Area
(Customers may experience weak or sporadic signals)
[J Globalstar Service Area currently unavailable to North American roamers Fig 8: Globalstar coverage Map
3.5 Comparison between Globalstar and Iridium
Globalstar Iridium
Coverage Most Land Area & Coastal Waters Truly Global
Voice Quality Excellent Good
Text Messaging 19 character (Incoming only) 120 Character
Data Speed 9.6Kbs 2.4Kbs
Portable Phone Price $645 $1,395
Airtime Rates $.17-$1 in US &Caribbean $.90-$l .73 Globally
4
INMARSAT SATELLITE SERVICE
Inmarsat was the world's first global mobile satellite communications operator and is still the only one to offer a mature range of modern communications services to maritime, land-mobile, aeronautical and other users.
Formed as a maritime-focused intergovernmental organization over 20 years ago. Inmarsat has been a limited company since 1999. serving a broad range of markets. Starting with a user base of 900 ships in the early 1980s, it now supports links for phone, lax and data communications at up to 64kbit/s to more than 240.000 ship, vehicle, aircraft and portable terminals. That number is growing at several thousands a month.
4.1 Inmarsat Communication
The Inmarsat network consists of four geo-stationary satellites 35,600km above the Earth. The satellites are positioned at equatorial points over the Indian Ocean, the Pacific Ocean and the Eastern and Western sides of the Atlantic. The 'footprint' created by this configuration is able to provide almost total global communication coverage with the exception of the Poles. The first advantage that this gives Inmarsat is, once a signal is sent to a satellite, its individual 'footprint' is often large enough to deliver that signal to its destination without having to transfer via another satellite first. This minimizes the risk of the signal being lost.
4.2 Inmarsat coverage Map
Mobile Satellite Communications
Fig 9: Inmarsat coverage Map
The main argument that has been leveled against Inmarsat terminals regards their size; they are comparable to modern laptop computers. Inmarsat rivals, Iridium and
Dcpt.ofF.CE.S.N.G.C.E
- 11 -
Globalstar, use handsets that are far more akin to cellular phones, which it is claimed, weightless and are easier to use. This is not an entirely unfair point; it is true that Inmarsat equipment is larger than that of its contemporaries. Where they can out perform Iridium and Globalstar is in their ability to transfer data and faxes. This lends Inmarsat much more effectively to the setting up of semi-permanent offices where, along side voice facilities, more capable fax and data services are required. When used in this capacity Inmarsat's size ceases to become such an issue. Inmarsat are planning to expand this service with their next generation satellites, due to go live in 2005. With this increase Inmarsat are aiming to supply superior Internet, Intranet and video services as well as voice, fax and data.
5
THURAYA SATELLITE SERVICE
Thuraya was launched in 2001 to offer high quality, affordable communications to areas of high population, where coverage of GSM docs not exist or is limited. This includes North and Central Africa, Middle East, India, Central Asia and Europe. Thuraya uses the latest available Satellite technology, and provides the first truly pocket size handheld telephone, with exceptional voice clarity and low airtime rates, including the use of low denomination Pre Pay scratch cards.
5.1 Thuraya System
Thuraya is an advanced geosynchronous mobile satellite system providing access to Satellite and GSM900 services from the same Handset. It offers the facility for high quality voice, voice mail and SMS as standard, together with an in built GPS. Data/fax facilities arc available through the optional data kit with speeds obtainable up to 9600bps which means reliable email or even web browsing.
Fi« 10: Thuraya mobile phone set
Thuraya allows you to roam with your handsel across nearly one third of the globe. If you are in Thuraya's coverage area you can call to. and receive a call from, anywhere in the world. Even outside the Thuraya coverage area you will still be able to use your Thuraya phone in GSM mode, through a Thuraya GSM roaming partner. The handset can be used as a Satellite only. GSM only, or auto switching between the two. subject to the type of airtime package chosen.
IRIDIUM PRODUCTS
6.1. 9500 Portable Satellite Phone
What is it
The 9500 Portable Satellite Phone provides global, reliable voice and data. Iridium Satellite provides solutions for individuals who live and work in areas outside of cellular network coverage, or in places with poor landline services. Satellite calls can be routed directly from the satellite phone to the Iridium satellites orbiting the earth.
Why do you need it
Iridium Satellite provides solutions for individuals who live and work in areas outside of cellular network coverage, or in places with poor landline services. Satellite calls can be routed directly from the satellite phone to the Iridium satellites orbiting the earth. Global satellite service enables users to communicate in many remote or under served regions where wireless or landline networks are limited, non-existent or developing.
Fig:ll 9500 phone
Features
. 10 Dedicated Control Keys for easy operation . Clock - displays home and travel time . Dedicated Keypad Cover
. Data Capable - Use your satellite phone to transmit data with an optional RS232 adapter
. Removable Satellite Antenna
. Weighs less than 16 ounces
. Multi-Language Support choices for prompts
6.2. 9505 Portable Satellite Phone
What is it
Now smaller, lighter and more resistant to water, dust and shock than the previous offering, this new addition is ideal for industrial or rugged conditions, yet appealing to the traveling professional. Why do you need it
Business, adventure, or pleasure, you can stay in touch across seas and time zones, in remote locations and on the go. One Telephone number, through the use of a mini personal Subscriber identity module (SIM) card can help keep you Connected.
Features
Fig 12:9505 phone
Quick Access Interface
Water, shock & dust resistant for rugged environments
Data Capable (use your satellite phone to transmit data with an optional RS232 adapter)
21 Language Choices for Prompts Vibracall Alert
Illuminated holographic display
6.3.9505A Portable Satellite Phone
What is it
Functionally similar to the Iridium 9505, this latest offering introduces some minor product changes. It is significantly smaller, lighter and more resistant to water, dust and shock than the original Iridium 9500 and is ideal for industrial or rugged conditions, yet appealing to the traveling professional.
Why do you need it
Business, adventure, or pleasure, you can stay in touch across Seas and time zones, in remote locations and on the go. One telephone number, through the use of a mini personal subscriber identity module (SIM) card, can help keep you connected.
Features
Quick Access Interface
Water, shock & dust resistant for rugged environments
Data Capable (use your satellite phone to transmit and receive data with an optional RS232 adapter) 21 language choices for prompts Headset/Hands-free capability
Fig 13:9505A phone
6.4.9501 Pager
What is it
The 9501 Pager is a lightweight and wearable one-way messagingdevice that keeps in touch wherever you are in the world. Combined with an Iridium Satellite phone, the pager offers one of the world's most extensive global wireless personal communications networks. Why do you need it
When you can't be out of reach, the 9501 Pager receives all your 1 messages, wherever your travels take you. This belt-worn pager offers a flexible, cost-effective global communications package for unlimited mobility.
Features
Easy to use Icon Driven Menu International Character Set
Optimax ™ EL Electro-luminescent Display - for exceptional readability
Stylish Lightweight Design
Real Time Clock with Dual Time Zones display
Multiple user selectable indicators or alerts
6.5.Common Features of Iridium Products
¢ Illuminated Graphic Display
¢ International Access Key Sequence
¢ Dedicated keypad cover
¢ Multi language support
¢ Selectable Ringer Tone
¢ Selectable Keypad Sequence
¢ Vibrating Alert
¢ Memory capacity
¢ SIM memory
¢ Volume adjustments
¢ Mailbox for numeric and text etc
GLOBALSTAR PRODUCTS
7.1.GSP 1600
QUALCOMM's Globalstar Tri-Mode mobile satellite phone is a light¬weight, handheld communications tool that operates with the Globalstar network virtually anywhere in the world. Short message service (SMS) and data services will be available in the near future.Additionally, Globalstar's Tri-Mode satellite phone automatically(or manually if programmed) switches pjg i5:GSP 1600 from the Globalstar satellite network mode to the digital cellular mode (CDMA) or North American analog (AMPS) mode within the caller's home network or when roaming to a neighboring network, reducing the cost of the call.
7.2.GSP 2900
QUALCOMM's Globalstar satellite-based fixed phone unit offers an innovative
solution for quick, easy installation of communication systems in remote,
hard-to-reach locations as well as in under-served urban and rural areas. The
Globalstar fixed phone unit can bring a dial tone to areas where traditional
telephone services are not economically feasible. The antenna and fixed phone Fig 16:GSP 2900 unit are mounted at a convenient outdoor location with a clear view of the sky and connected to a variety of available indoor phone units using standard telephone
cable. The GSP-2900 is suitable for voice and data (9.6 KBps packet data) services, has
an international coverage area, and supports all Globalstar Service Plans. A remotable
antenna is available.
7.3.FAU 200
QUALCOMM's Globalstar satellite-based fixed phone unit, the
FAU-200, for half the price of the GSP-2900 Fixed Phone. Ideal for
voice service only and coverage in the US/Caribbean Home Service Are
The Globalstar FAU-200 Fixed Phone is the ideal cost-effective
solution for installed satellite telephone voice service virtually
anywhere. It enables remotely located businesses and individuals to Fig 17:FAU 200
connect into the public telephone network through the Globalstar system, using standard telephone equipment and wiring. A remotable antenna is not available.
8. CONCLUSION
As you can see from the above satellite services highlighted, there is not one all encompassing system that can out perform its rivals in al areas. Each has certain strengths and weaknesses.
If you decide that you need to use satellite phone, you need to decide which satellite network is best for you. You must access what functions are most valuable to you; Do you need total global coverage Do you need the ability to send and receive data Do you want something that is easy to carry
In future, satellite phones will be in the place of ordinary mobile phones...
9. REFERENCES
1 .iridium.com 2.globalstar.com 3.inmarsat.com 4.moblephonesites. co.uk 5.infokairali computer Magazine (Vol.7 No.3)
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27-03-2010, 01:12 AM

hello can u please send ppt for this topic please....
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31-03-2010, 07:31 AM

ADVANCED COMMUNICATION TRENDS
SATELLITE PHONES


Presented By:
K.Veerebhadrudu
K.A.Udaya kumar
Rajeev Gandhi Memorial College of Engineering &Technology

ABSTRACT
As businesses become more transportable and business men and women travel around the globe, using a digital cell phone service simply isnâ„¢t adequate. Many times people have to travel to remote areas or places where service is simply not available for their cell phone. The service systems which donâ„¢t run into this problem and can always count on having communication service any where at all time is providence.
After 9/11 one can realize how a stringent activity can turn the world upside down and leave us with the feeling of how vulnerable we can be. When the twin towers were hit the landline and cellular systems in New York where overloaded or disrupted. People in New York had a difficult time calling out to family and friends to let them know they where OK. People calling into New York had problems getting through because most of the circuits where busy. After this terrible act of terrorism numerous government agencies realize it was necessary to have emergency back up communications in the form, which do not rely on local phone systems.
INTRODUCTION:
Communication is defined as exchange of thoughts, messages, or information, as by speech, signals, writing, or behavior.
Types of communication systems:
Communication systems are broadly classified as
¢ Wired
¢ Wireless
An advanced wireless communication system includes the following types;
¢ Satellite communication
¢ Mobile communication
And now narrowing down to satellite communication:
¢ Satellite phone
¢ Global positioning system
SATILLITE PHONE
A telephone that transmits and receives from satellites that provides coverage around the world. Over eighty percent of the land on earth plus any body of water (we're talking oceans here) is without sufficient landline connection, depending on the architecture of a particular system, coverage may include the entire Earth, or only specific regions. With a satellite phone we are able to communicate with anyone with a phone number from almost anywhere. The sat phone more closely resembles our portable home phone or one of those clunky cell phones from fifteen years ago.
Iridium was the first satellite phone company.
An actual satellite phone can also be referred to by professionals in the satellite service field as a terminal or Ëœearth stationâ„¢. Some satellite phones can be chunky and reminiscent of the type of cell phones that were used in the 1980â„¢s, but not all are made that way. Satellite phone shapes and sizes are changing much in the same way that digital phones have over the past decade. These are popular on expeditions into remote areas where terrestrial cellular service is unavailable.
A fixed installation, such as used shipboard, may include large, rugged, 9rack-mounted electronics, and a steer able microwave antenna on the mast that automatically tracks the overhead satellites.
THE NEED FOR SATILLITE PHONE SYSTEM
There are only two ways to hook up two telephones in different parts of the world: they can be connected by a cable which runs on the surface of the earth and under the sea, or they can be connected by radio. Not every place on the earth is served by a cable connection to the Public Switched Telephone Network (PSTN), and thus some locations must either have no telephone
service or be connected to the PSTN by a radio link.
Modern cellular phones in the industrial countries mostly work in the cities and on the major highways. This is because each cell is a radio link from the cell phone to the PSTN; and if a cell phone user is located where there are no cells, there is no service.
Because the earth is round, and because most radio waves travel in straight lines, it is not possible to form a direct radio link to a telephone or a gateway to the PSTN which is located over the horizon. An exception to this rule are the low frequency bands which can follow the curvature of the earth, but these frequencies were all allocated for other purposes decades ago and are not generally available for telephone service. Also it is possible to have a line of radio relay stations that stretch along the earth, but these are only practical for a large number of circuits carried by the PSTN. They play a similar role to the surface cables of the PSTN and are not generally available to individual subscribers.
Almost all of the world-wide telephone voice traffic is currently carried by surface and under-sea cables. This has now changed because satellite phones have now become operational.
Fig (a): overview of ordinary mobile communication


Fig (b): overview of satellite phone system
What makes it superior
Differences between ordinary communication and the satellite phone communication is it involves the other towers for the sake of the communication it they are ot available the network fails but as the satellite phones does not have no intermediate towers so communication link rarely get breaked.
TYPES OF SATELLITE PHONE SYSTEMS
There are four different satellite phone systems that have reached general popularity. They are
Globalstar, Inmarsat, Iridium and Thuraya.
GLOBALSTAR: This satellite service plans were specifically designed to meet the needs of those who travel extensively. Consequently, they designed a phone that is a compact, tri-band handset that is able to operate on both the cellular CDMA and AMPS networks as well as the Globalstar network that consists of 48 low earth orbiting satellites. The benefit for those who take advantage of Globalstar plans is that the phones were created to switch smoothly between the cellular networks and the satellite network even while the phone is in use. Whenever possible, a Globalstar satellite phone will only use the cellular networks and switch to satellite only when they arenâ„¢t available. This offers customers the most cost effective satellite service available.
INMARSET: It was the first mobile satellite system conceptualized and brought to reality. Inmarset originally designed their satellite phones for the maritime industry, but they now offer phone service to a wide range of industries. Inmarset uses four geo-stationary satellites set at different locations over the equator.
IRIDIUM: This is probably the most recognized name in the satellite service industry. Iridium openly went bankrupt just one year after they launched their service. Motorola intervened, paid Iridiumâ„¢s debts, re-launched satellite service in 2001 and has been providing successful service since. Iridium uses 66 satellites that orbit the earth on six different planes. Each individual Iridium satellite is able to orbit the earth once every 100 minutes. This arrangement allows Iridium to make sure that any Iridium handset can receive and make satellite phone calls from anywhere on the planet.
THURAYA: It allows us to switch between the satellite system and the GSM system. The Thuraya service can roam on the local cellular network by replacing the Thuraya SIM card with a local prepaid SIM card. On the local network you are charged the local rates and not the Thuraya roaming rates. Thuraya satellite phones are capable of Internet connectivity, and data is available at no extra charge. Thuraya covers entire Europe and then Middle East, parts of India, Asia, and Africa.
WORKING:
Even though it is called a "phone", the satellite phone is in actuality a radio transmitter. It sends signals directly to a satellite (part of a network of satellites.). When you turn on your satellite phone the signal goes up to any number of satellites in a compatible constellation where it is then registered with the constellation.
Those signals are then sent back to earth to a station. The Gateway(earth station) processes and takes care of the switching of the calls rather than the satellite network. This station then directs the call to the Public Switched Telephone Network (PSTN) or to a cellular network. If you are calling from a cell or wired phone to a satellite phone, the system works in reverse. Or think of a satellite phone calling another satellite phone. The signal goes up to the satellite, down to earth, back up to a satellite and then back down to earth again.
The frequency specification of a satellite phone is 626.5 to 1660.5 Mhz for transmitter and 1525.0 to 1559.0 MHz for receive
LINE OF SIGHT
With most satellite communication devices we need Line-of-Sight to the satellite we are communicating with which include GPS devices, satellite TV, satellite Internet, satellite modems, hand held satellite phones and fixed site satellite phones. When using a hand held satellite phone we need at least 80% view of the sky to receive good service or we must use an external antenna with an 80% view of the sky.
The success in making calls would depend on where the satellites are positioned at the moment the phone is used. Globalstar and Iridium both have LEO Low Earth Orbiting satellites. If we have a very limited view of the sky when using a satellite phone and have no service we eventually would have line-of-sight with one of the satellites orbiting the earth.
Globalstar uses a constellation of 48 satellites that orbit the central hemisphere of the earth covering over 120 countries. Globalstar uses the technology which uses path diversity. Path diversity allows the Globalstar phone to be linked to as many as four satellites at one time. This technology prevents dropped calls when the line of sight is blocked to one of the satellites.
The call is sent from the satellite down to the ground station and is then delivered to its call destination by land-line. If the user of the Globalstar phone is calling another Globalstar phone the call goes down to the ground station then back up the constellation then down to the other Globalstar phone. With the hand held phone there is an option of a car kit or docking station which includes a low provide magnetic external antenna witch allow line-of-site to the satellites while using the phone in a vehicle. GlobalCom offers a number of the Globalstar fixed site units which includes an external antenna that can be placed outside the building or vehicle. With the Globalstar fixed site phones we can have a number of (off the shelf) desktop or cordless phones tied into the unit. After installation the phones work just like a land-line phone with a dial tone.
Iridium uses a constellation of 66 satellites that orbit the poles they travel from pole to pole and give coverage virtually everywhere on the planet which includes all the oceans and land masses. One of the way the Iridium phone can offer planetary coverage by taking the call and handing it off from satellite to satellite and then down to the closes Iridium ground station which the call is then sent to its call destination by land-line. If the user of the Iridium phone is calling another Iridium phone then the call is totally handled by the satellite constellation and is not sent to the gateway. Iridium does have optional portable and mast external antennas available.
LOW EARTH ORBIT:
A LEO telephones utilizes LEO (low Earth orbit) satellite technology. This includes provision of worldwide wireless coverage with no gaps. Newer satellite phones tend to be LEOs. LEO satellites orbit the earth at high speed, low altitude orbits with an orbital time of 70“90 minutes, an altitude of 640 to 1120 kilometers (400 to 700 miles), and provide coverage cells. Since the satellites are not geosynchronous, they must fly complete orbits and thus further guarantee complete coverage over every area by at least one satellite at all times. Blimps are being considered as an alternative to satellites.
ADVANTAGES:
This system covers the entire globe.1
Tracking the data transmitted is impossible.
This communication does not rely on land line systems.
Towers on the Earth are not required.
APPLICATIONS:
It is highly useful in rescue operations at the times of disasters.
It is also used by the deep sea vessels for communication.
The phones are mostly used by the confidential system of any nation.
DISADVANTAGES:
DELAY: A disadvantage of a satellite phone is a noticeable delay in conversations. The signal must first travel to the satellite, then to an earthbound gateway before being routed to the receiver. The receiver's response will follow the same path in reverse, taking equally long to reach the caller. Satellite minutes are also more expensive than cellular minutes.
BANDWIDTH: Another downside of the satellite phone is the limitations of bandwidth. Some satellite phones use a narrow band, sending along our audio signal, but they cannot handle the high bandwidth information at near the speeds we find at home.
AFFORDABILITY: The cost at which the service is being provided is high. That is the call charge per minute is approximately Rs. 92.00, which is quite annoying.. FUTURE ADVANCEMENTS:
Globalstar has plans in the future to send their satellite signal over terrestrial cellular towers allowing the signal to penetrate obstructions like building and vehicles. The phone would be in terrestrial mode when line-of-site to the satellite was obstructed then when line-of-site to the satellite constellation could be obtained then the phone would switch to satellite mode. The satellite communication industry is a growing field that is ever changing. As the technology develops humans will enjoy additional services never before offered.
CONCLUSION:
However, these drawbacks are irrelevant when considering the function that a satellite phone serves. It can create a link to civilization from places where no other link is available. It also allows loved ones to stay in touch, as in the case of researchers, adventurers and those in the military, and it can provide backup communication in disasters when cellular towers or landlines might not be functional.
References
Communication systems by HAYKIN.
Antenna and wave propagation by K.D.PRASAD.
globalcom.com
iridium.com
globalcommunications.com
and extended links.


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Satellite telephones

Presented By :
Dusmant Sahu
M C A 4th Semester


CONTENT

INTRODUCTION
What is a satellite phone
Geostationary Orbit
LEO Orbit
SATELITE PHONE SERVICES
Global star System
How do satellite phones work
Advantage
Disadvantage
Conclusion



INTRODUCTION


Probably the largest area of satellite usage is the telephone market. Satellite phones have become
an essential part of communicating for businesses professionals, and even individuals. Sure cell
coverage is found in most developed areas but
not in more remote areas or undeveloped areas
such as third world countries. Thatâ„¢s where satellite phones are needed. In fact you can communicate around the world with a Global satellite phone.



WHAT IS A SATELLITE PHONE

A satellite telephone, satellite phone, or satphone is a mobile phone that communicates directly with orbiting communications satellites and the coverage area may include the entire earth.
Satellite telephones are utilized in circumstances where there is no access to a telephone or cellular network.
The Satellite phones either make use of satellites in geostationary orbit or they make use of satellites in low earth orbit.



GEOSTATIONARY ORBIT


A geostationary orbit (GEO) is an geosynchronous orbit directly above the Earth's equator (0º latitude). Satellite orbits in the direction of the Earth's rotation, at an altitude of approximately 35,786 km above ground. This altitude is significant because it produces an orbital period equal to the Earth's period of rotation




LOW EARTH ORBIT


A low Earth orbit (LEO) is generally defined as an orbit within the locus extending from the Earthâ„¢s surface up to an altitude of 2,000 km.


SATELITE PHONE SERVICES

¢ GEOSTATIONARY SERVICES
¢ LEO SERVICES


GEOSTATIONARY SERVICES

These satellite phones use satellites in the
geostationary orbits. They can maintain near-
continuous global coverage with only three or four satellites,
reducing the launch costs.


DISADVANTAGE

The satellite is so far away (approx. 22,000 miles) that a
comparatively large antenna system is required for signal
transmission and reception.


EXAMPLES

Inmarsat satellite system




INMARSAT SATELLITE PHONE SYSTEM

Inmarsat plc is an international telecommunications company founded in 1979, originally as an intergovernmental organization.
It operates a fleet of 11 geosynchronous communication satellite.
Inmarsat provides telephony and data services to users world-wide


SERVICE PROVIDED

Services include traditional voice calls , high-speed data services and facility like GPRS is also provided at the rate of 492 kbps.
The voice calls rate are the same wherever in the world service is used.



¢ LEO SERVICES

LEO satellites orbit the earth at high speed, low altitude orbits with an orbital time of 70“90 minutes, an altitude of 640 to 1120 kilometres and provide coverage cells.
EXAMPLE
Iridium satellite phone system
Globalstar satellite phone system


Iridium satellite Phone System

This system originally had 77 active satellites and hence it is
called IRIDIUM which is the name of an element whose atomic number is 77.
Now it has a fleet of 66 active satellites.
This service was launched in nov1,1998. But it could not
survive because of the high cost of calls and large size of the hand sets.




Global system

Globalstar satellite phone service is delivered through 48 Low-Earth-Orbiting satellites providing both voice and data services.
The Globalstar LEO constellation is only 700 miles from earth which allows for the highest quality voice clarity of any satellite phone in the industry.


Globalstar satellite phone System

When a call gets initiated it is picked up by 4 satellites which combine the signals into one signal. This combined signal is then transmitted to one of several terrestrial "gateways." The gateways are the ground stations who direct the signal to the call destination.




ADVANTAGES

Since the call is being picked up by 4 satellites the probability of call blocking is greatly reduced.
no interruption.



HOW DO SATELLITE PHONES WORK

Just like cellular phones, satellite phones use radio waves to send their signal. Because satellite phones use satellite signals, the antenna is a little larger, and they must be used in an area where there is unobstructed sky.




ADVANTAGES OF SATELITE PHONE

Use in disaster response
Reliability
Easier to use (similar to using a mobile phone)
No installation required
Easy for other people to call you



DISADVANTAGES

A disadvantage of a satellite phone is a noticeable delay in conversations. The signal must first travel to the satellite, then to an earthbound gateway before being routed to the receiver. The receiver's response will follow the same path in reverse, taking equally long to reach the caller.
Satellite phones are also more expensive than cellular phones.


CONCLUSION

The call path of the satellite phones is disaster free.
Provides global coverage.

But still satellite phones are not as popular as the cellular phones probably because of the high cost of the calls. It is very famous in European countries but it has not become popular in the Asian countries.
Research is going on in order to decrease call cost so that satellite phone becomes a common manâ„¢s phone
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ADVANCED COMMUNICATION TRENDS
SATELLITE PHONES

ABSTRACT
As businesses become more transportable and business men and women travel around the globe, using a digital cell phone service simply isn’t adequate. Many times people have to travel to remote areas or places where service is simply not available for their cell phone. The service systems which don’t run into this problem and can always count on having communication service any where at all time is providence.
After 9/11 one can realize how a stringent activity can turn the world upside down and leave us with the feeling of how vulnerable we can be. When the twin towers were hit the landline and cellular systems in New York where overloaded or disrupted. People in New York had a difficult time calling out to family and friends to let them know they where OK. People calling into New York had problems getting through because most of the circuits where busy. After this terrible act of terrorism numerous government agencies realize it was necessary to have emergency back up communications in the form, which do not rely on local phone systems.
INTRODUCTION:
Communication is defined as exchange of thoughts, messages, or information, as by speech, signals, writing, or behavior.
Types of communication systems:
Communication systems are broadly classified as
• Wired
• Wireless
An advanced wireless communication system includes the following types;
• Satellite communication
• Mobile communication
And now narrowing down to satellite communication:
• Satellite phone
• Global positioning system
SATELLITE PHONE:
A telephone that transmits and receives from satellites that provides coverage around the world. Over eighty percent of the land on earth plus any body of water (we're talking oceans here) is without sufficient landline connection, depending on the architecture of a particular system, coverage may include the entire Earth, or only specific regions. With a satellite phone we are able to communicate with anyone with a phone number from almost anywhere. The sat phone more closely resembles our portable home phone or one of those clunky cell phones from fifteen years ago.
“Iridium was the first satellite phone company”.
An actual satellite phone can also be referred to by professionals in the satellite service field as a terminal or ‘earth station’. Some satellite phones can be chunky and reminiscent of the type of cell phones that were used in the 1980’s, but not all are made that way. Satellite phone shapes and sizes are changing much in the same way that digital phones have over the past decade. These are popular on expeditions into remote areas where terrestrial cellular service is unavailable.
A fixed installation, such as used shipboard, may include large, rugged, 9rack-mounted electronics, and a steer able microwave antenna on the mast that automatically tracks the overhead satellites.
The Need for Satellite Phone Systems
There are only two ways to hook up two telephones in different parts of the world: they can be connected by a cable which runs on the surface of the earth and under the sea, or they can be connected by radio. Not every place on the earth is served by a cable connection to the Public Switched Telephone Network (PSTN), and thus some locations must either have no telephone service or be connected to the PSTN by a radio link.
Modern cellular phones in the industrial countries mostly work in the cities and on the major highways. This is because each cell is a radio link from the cell phone to the PSTN; and if a cell phone user is located where there are no cells, there is no service.
Because the earth is round, and because most radio waves travel in straight lines, it is not possible to form a direct radio link to a telephone or a gateway to the PSTN which is located over the horizon. An exception to this rule are the low frequency bands which can follow the curvature of the earth, but these frequencies were all allocated for other purposes decades ago and are not generally available for telephone service. Also it is possible to have a line of radio relay stations that stretch along the earth, but these are only practical for a large number of circuits carried by the PSTN. They play a similar role to the surface cables of the PSTN and are not generally available to individual subscribers.
Almost all of the world-wide telephone voice traffic is currently carried by surface and under-sea cables. This has now changed because satellite phones have now become operational.
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ADVANCED COMMUNICATION TRENDS SATELLITE PHONE
ABSTRACT

Many times people have to travel to remote areas or places where service is simply not available for their cell phone. The service systems which don’t run into this problem and can always count on having communication service any where at all time is providence.
Types of communication systems:
 Wired
 Wireless
 An advanced wireless communication system includes the following types;
 Satellite communication
 Mobile communication
What makes it superior?
 Differences between ordinary communication and the satellite phone communication is it involves the other towers for the sake of the communication if they are not available the network fails but as the satellite phones does not have no intermediate towers so communication link rarely get breaked.
TYPES OF SATELLITE PHONE SYSTEMS:
 Globalstar
 Inmarsat
 Iridium
 Thuraya
 INMARSAT: It was the first mobile satellite system conceptualized and brought to reality. Inmarset uses four geo-stationary satellites set at different locations over the equator.
 IRIDIUM: Iridium uses 66 satellites that orbit the earth on six different planes. Each individual Iridium satellite is able to orbit the earth once every 100 minutes. This arrangement allows Iridium to make sure that any Iridium handset can receive and make satellite phone calls from anywhere on the planet.
 GLOBALSTAR: This satellite service plans were specifically designed to meet the needs of those who travel extensively. Consequently, they designed a phone that is a compact, tri-band handset that is able to operate on both the cellular CDMA and AMPS networks as well as the Globalstar network that consists of 48 low earth orbiting satellites
 THURAYA: It allows us to switch between the satellite system and the GSM system. The Thuraya service can roam on the local cellular network by replacing the Thuraya SIM card with a local prepaid SIM card. On the local network you are charged the local rates and not the Thuraya roaming rates. Thuraya satellite phones are capable of Internet connectivity, and data is available at no extra charge. Thuraya covers entire Europe and then Middle East, parts of India, Asia, and Africa.
 It sends signals directly to a satellite . When you turn on your satellite phone the signal goes up to any number of satellites in a compatible constellation where it is then registered with the constellation.
Those signals are then sent back to earth to a station. The Gateway(earth station) processes and takes care of the switching of the calls rather than the satellite network. This station then directs the call to the Public Switched Telephone Network (PSTN) or to a cellular network. If you are calling from a cell or wired phone to a satellite phone, the system works in reverse.
 The signal goes up to the satellite, down to earth, back up to a satellite and then back down to earth again.
 Frequency specification of a satellite phone is 626.5 to 1660.5 Mhz for transmitter and 1525.0 to 1559.0 MHz for receiver.
ADVANTAGES:
 This system covers the entire globe.
 Tracking the data transmitted is impossible.
 This communication does not relay on land line systems.
 Towers on the Earth are not required.
APPLICATIONS:
 It is highly useful in rescue operations at the times of disasters.
 It is also used by the deep sea vessels for communication.
 The phones are mostly used by the confidential system of any nation.
DISADVANTAGES
 DELAY: The signal must first travel to the satellite, then to an earthbound gateway before being routed to the receiver. The receiver's response will follow the same path in reverse, taking equally long to reach the caller.
 BANDWIDTH: Some satellite phones use a narrow band, sending along our audio signal, but they cannot handle the high bandwidth information at near the speeds we find at home.
 AFFORDABILITY: The cost at which the service is being provided is high.
CONCLUSION:
 However, these drawbacks are irrelevant when considering the function that a satellite phone serves. It can create a link to civilization from places where no other link is available. It also allows loved ones to stay in touch, as in the case of researchers, adventurers and those in the military, and it can provide backup communication in disasters when cellular towers or landlines might not be functional.
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ABSTRACT
SATELLITE PHONES

A satellite telephone, satellite phone, or sat phone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites. Depending on the architecture of a particular system, coverage may include the entire Earth, or only specific regions. Early satellite phones handsets had a large size and weight with a large retractable antenna. Recent sat phones are small in size comparable with the earlier sat phones. Sat phones are popular on expeditions into remote areas where terrestrial cellular service is unavailable. A fixed installation, such as one used aboard a ship, may include large, rugged, rack-mounted electronics, and a steer able microwave antenna on the mast that automatically tracks the overhead satellites. Some satellite phones use satellites in geostationary orbit, which are meant to remain in a fixed position in the sky at all times. Disadvantage of geostationary satellite systems is that in many areas—even where a large amount of open sky is present—the line-of-sight between the phone and the satellite is broken by obstacles such as steep hills and forest. This disadvantage can be overcome with the low earth orbit (LEO). The advantages include providing worldwide wireless coverage with no gaps. LEO satellites orbit the earth in high speed, low altitude orbits. Satellite phones are usually issued with numbers in a special country calling code. Most mobile telephone networks operate close to capacity during normal times and large spikes in call volumes caused by widespread emergencies often overload the systems just when they are needed the most. Also, terrestrial cell antennas and networks can be damaged by natural disasters. Satellite telephony can avoid this problem and be critical in natural disaster communications. Satellite phone networks themselves are prone to congestion as satellites and spot beams cover a very large area with relatively few voice channels.
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