Global positioning system

Our ancestors used to work extremely hard to protect themselves from getting lost in this mysterious world. They used to erect monumental landmarks, study conventional land maps and of course they used to mark the stars in the night sky.

But today it is very easy to know one’s position. You just only have to get a pocket-sized gadget that will make you know your exact position on this earth at any given moment. The system of knowing one’s exact position on this earth is known as ‘Global Positioning System’. If anyone has a Global Positioning System (GPS) receiver, and if the sky remains clear, then no way can he gets lost on this earth.

Of note is that this pocket-sized gadget, the Global Positioning System receiver, is quite expensive and it also involves a fair amount of technical ingenuity.

GPS is specially a Satellite Navigation System that helps in tracking our exact location with the help of satellites. The Global Positioning System is mainly funded and controlled by the U.S Department of Defense (DOD). The system was primarily designed for the operation of U. S. military. But there are also many civil users of GPS across the globe. The Global Positioning System provides some special satellite signals which are then processed in the GPS receiver. These GPS receiver’s not only track the exact location, but can also compute velocity and time.

The positions can even be computed in three dimensional views with the help of four GPS satellite signals. The Space Segment of the Global Positioning System consists of the GPS satellites. These satellites send radio signals from space which are received by the GPS receiver.

There are more than 24 operational and 3 extras (in case one fails) GPS satellites that moves round the Earth every 12 hours.

The control of the Global Positioning System consists of different tracking stations that are located across the world. These monitoring stations help in tracking signals from those Space Vehicles which are continuously orbiting the earth. The Space Vehicles transmit microwave carrier signals. The users of the Global Positioning System have GPS receivers that convert the satellite signals which estimate position, velocity and time. Four satellites are required to track the three dimensional location and time. The primary function of Global Positioning System is the navigation in three dimensions. The Navigation receivers are used for aircraft, ships, and ground vehicles and sometimes for personal use as well.

With GPS receivers, precise positioning of any location can be done. The Global Positioning system is based on a simple mathematical calculation that operates through a process called Trilateration. In order to make the simple mathematical calculation the GPS receiver should know two things.

++ One is the location of the place to be traced by at least three satellites.

++ Secondly, is the distance between the where the receiver is located and each of those Space Vehicles.

All units have multiple receivers, and can pick up signals from several GPS satellites at a same time. These radio waves are electromagnetic energy that travels at the speed of light.

The civil users across the world are allowed to use the Standard Positioning Service without any kind of charge or restrictions.

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As most of you know GPS is an acronym for Global Positioning System, but how does global positioning really work?

The Global Positioning System is a satellite-based navigation system, consisting of more than 20 satellites and several supporting ground facilities, which provides accurate, three-dimensional position, velocity, and time, 24 hours a day, everywhere in the world, and in all weather conditions.

The Global Positioning system consists of three main components:

1. GPS Ground control stations.

The ground control component includes the master control station at Falcon Air Force Base, Colorado Springs, Colorado and monitor stations at Falcon AFB, Hawaii, Ascension Island in the Atlantic, Diego Garcia in the Indian Ocean, and Kwajalein Island in the South Pacific. The control segment uses measurements collected by the monitor stations to predict the behavior of each satellite’s orbit and atomic clocks. The prediction data is linked up to the satellites for transmission to users. The control segment also ensures that GPS satellite orbits remain within limits and that the satellites do not drift too far from nominal orbits.

2. GPS satellites.

The space segment includes the satellites and the Delta rockets that launch the satellites from Cape Canaveral in Florida, United States. GPS satellites orbit in circular orbits at 17,440 km altitude, each orbit lasting 12 hours. The orbits are tilted to the equator by 55° to ensure coverage in polar regions. The satellites are powered by solar cells to continually orientate themselves to point the solar panels towards the Sun and the antennas towards the Earth. Each satellite contains four atomic clocks.

3. GPS receivers.

When you buy a GPS, you are actually buying only the GPS receiver and get free use of the other two main components, worth billions of dollars - compliments of the Government of the United States. (If you don’t have a GPS, BUY ONE NOW, before somebody finds a way to commercialize it and start charging for the service.)

The ground stations send control signals to the GPS satellites, The GPS satellites transmit radio signals and the GPS receivers, receive these signals and use it to calculate its position.

The calculations used to determine your GPS receiver’s position is based on very small time differences, from when the satellite transmitted the signal, to, when the GPS receiver received the signal. These small differences are then used to calculate the distance from the receiver to the satellite. However, when receiving only one signal, we can only calculate how far away from the satellite we are. When receiving two signals, we can determine two likely positions where we are. We need three satellite signals to determine our exact position on the earth’s surface. (2D/2 Dimensional positioning). When more than three satellites are “visible” to the GPS receiver, it will also calculate the altitude of the receiver (3D/3 dimensional positioning).

Your GPS receiver requires signals from at least three satellites to determine your unique position on the earth’s surface. With a fourth signal your altitude can also be determined. Receiving signals from more than four different satellites, the position of the GPS receiver can more accurately be determined.

The GPS satellite constellation is designed in such a manner as to guarantee that at least 4 satellites are visible from any place on earth at any moment in time. Most of the time (+95%) however, you should have at least 6 satellites visible. Many commercial GPS receivers can receive and process signals from 12 satellites for increased reliability and accuracy.

GPS satellites carry atomic clocks that measure time to a high degree of accuracy. The time information is placed in the codes broadcast by the satellite so that a receiver can continuously determine the time the signal was broadcast. The signal contains data that a receiver uses to compute the locations of the satellites and to make other adjustments needed for accurate positioning. The receiver uses the time difference between the time of signal reception and the broadcast time to compute the range to the satellite. The receiver must account for propagation delays caused by the ionosphere and the troposphere. With three ranges to three satellites and knowing the location of the satellite when the signal was sent, the receiver can compute its three-dimensional position.

To compute ranges directly, however, the user must have an atomic clock synchronized to the global positioning system. By taking a measurement from an additional satellite, the receiver avoids the need for an atomic clock. The result is that the receiver uses four satellites to compute latitude, longitude, altitude, and time.

Why should you use a GPS receiver ? GPS receivers will become as commonplace as cell phones, very soon!

No more getting lost - Get to your destination on time.
Have confidence when traveling - no more wondering which way, left or right.

Ease of use - It is easier to use a GPS receiver than to navigate by using a map. On the GPS screen you can see where you want to go, just like in a map, but you can also see where you are!

GPS receivers are going to replace traveling maps - GPS receivers are smaller to carry, easier to handle, much more versatile and updateable.

Personal navigation with a GPS also means you can customize maps as you go along - plotting points of interest and marking all those wonderful places in an easy, neat and ordered manner.

GPS receivers will also provide you with traveling support information, such as:
the estimated time of arrival (ETA) at your selected destination, how much fuel you have left (much more accurate than your fuel gauge in the car or truck)
Your true speed (with an accuracy of +/- 0.1 km/h).

Log your route as you travel to keep an accurate record of your traveling in case you need to trace back your steps. This is true for short hiking trips to routes of many hundreds of miles.

Time information on all GPS receivers are continuously adjusted from the atomic clocks used in the GPS system - the most accurate time and timing sources available today.

So you better get on board and start using, for free, all this billions of dollars worth of technology - with the compliments of the USA !

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You have often heard of people complaining about the dearth of the jobs that is plaguing the industry currently. However, more than the market situation, what is important is the way you are looking out for the job. If you search jobs by going through the classified section of your paper religiously, then it is time we told you to look around, as things are changing. You can also try using the Internet in looking for a job of your choice.

Going by the hype and popularity of the Internet medium, majority of newspapers have started putting their classified advertisement section on the web. This gives people an opportunity of getting in direct contact with recruiting agency. This has also cut the task considerably as now there are no hassles of making calls to the agency.

Nowadays, there are many online job search engines on which you can submit your resume and which are free for the viewing of a potential recruiter. While viewing your resume if the recruiter feels you fit the brief you will be contacted by him directly. All these sites actually serve the job of the headhunter agencies and that too without the involvement of any payment.

On the other hand, you can access these internet based job search engines to find the job that best suits you. The employing agencies advertise thousands of jobs on these websites. You are sure to find something that’s waiting to be filled by someone with your expertise. If you find one that suits you, you can contact them directly and follow it up. Even necessary forms are available online.

If you are interested in freelance work, there are a number of websites on the World Wide Web that provide jobs to qualified individuals. These sites are valuable tools for anyone wishing to enter the realm of freelance, either as a job or as a supplement to your income. If you are in need of some extra cash for a car payment, house payment, retirement fund, or just plain pocket money, check out this excellent option.

Craiglist.org is a useful website for not only finding some great deals on furniture, tickets, automobiles and real estate but also has a classified section for employment. Thus chances are that you might just hit the jackpot by getting a perfect job on this website.

The very first step to begin the online job search is to have a well-revised and updated resume. The reason behind this is that all potential recruiters look for the best-written resumes. These days apart from having a paper copy you can also email the resume to the recruiters for that particular job.

Whereas landing with a job in the past was no less than an arduous journey due to the fact that the potential employees had to scout a lot in order to come across any good opportunity. However, this generation has it easy with the jobs proverbially, “Just a click away.” Looking out for a job just means settling in front of the PC at your home and browsing through that job waiting for you. So, show the way out to that old classified advertisement section!!

Aol broadband is the only provider that gives you the choice of connecting to a high speed broadband package. The broadband connection is also available via cable modem. Home computers are connected to internet by a cable modem and in the process NTL´s cable network is used. Often one wonders if Aol broadband will affect the telephone service or not. The best thing about the connection is that one can be online and you can use the phone at the same time.

If you choose the Aol ADSL (asymmetric digital subscriber line) product the Aol broadband in a Box Package will contain special filters that plugs in the normal phone socket to allow one to use the phone and be online at the same time. If you choose the broadband cable product there is no need of using filter on the telephone line since the broadband connection is delivered via cable modem and not the telephone line.

To get Aol Broadband Gold one needs to have either a BT phone line or be the inhabitant of NTL broadband enabled area. The Aol broadband access is subjected to local availability and capacity levels and the landlord´s permission.

However there are certain requirements needed for the PC. Windows 98 Second Edition Windows, Windows 2000, at least a Pentium 233MHz processor, at least 64MB system memory, a spare USB port for Aol broadband Gold or a spare Ethernet port for Aol broadband Platinum. If there are certain services like ISDN home highway it is not possible to get this broadband service. For the Aol broadband cable product none of these restrictions are present.

If you install this broadband via an existing BT phone line there is no need of permission as long as phone line is in your name. NTL engineers installs the cable modem if you choose the broadband cable product. Then Aol broadband software is installed and one can start to enjoy the broadband features and benefits. No connection fee is needed for the modem or router. Payment is a monthly subscription fee due to access to Aol and internet via your broadband connection.

The Aol broadband Silver and Aol broadband Gold Box will contain a single broadband modem, three filters, CD that contains modem driver software plus your software, all cables that you need and certain easy step by step guide of how to install. Aol Platinum needs wireless contains router, three filters, a CD containing software, all cables that one needs and a guide of how to install.

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Road Runner is a division of Time Warner Inc providing internet service through cable most notably through the Time Warner Cable. It is an Internet Service Provider providing the service over DOCSIS compatible cable modems. Road Runner provides service across the United States. The companies which are offering Road Runner are Time Warner Cable, Insight Communications, Urban Cable Works, Bright House Networks and America Online.

Offer: Road Runner offers a super fast Internet connection through cable.
Road Runner provides a constant online connection, hence there is no need for dialing or any question of disconnecting from the internet. Also a great flexibility is available to the customer in the choice of the connection as there are no long term contracts or obligations to be signed.

Availability: Road Runner is available in Alabama, Arkansas, California, Florida, Mississippi, Missouri, Nebraska, New Hampshire, Ohio, Pennsylvania, South Carolina, Tennessee, Georgia, Hawaii, Indiana, Kansas, Louisiana, Maine, Michigan, Minnesota, New Jersey, New York, North Carolina, Texas, West Virginia and Wisconsin. However to confirm whether it is available in your street, you have to visit the website www.rr.com and enter your address. The website rms about the availability.

Features: Road Runner provides the modem, installation, tools and a good customer support. The extras include multiple email accounts, personal home page space, instant messaging, dial access/web mail etc. The speed is up to 8 Mbps (Mega bits per second). At this speed you can easily share or download movies, songs etc from the internet. Road Runner is also giving a 30 day money back guarantee in case you are not satisfied with their service.

Hardware: Hardware consists of a splitter to split the coaxial cable cord and one output goes to your TV and the other goes to the modem. From the modem the output goes to your computer. Your computer should have a USB port or an Ethernet card for connection. The modem also needs a power point.

Obtaining Road Runner: This is fairly simple. First go to the website and check availability at your place. The website will return various services available. Next choose the service of your liking. The modem and installation will be done by the company. If you want to save some money, you can obtain the installation kit from the Road Runner local representative and install the modem yourself.

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