How Do I Choose A GPS Navigation System?

You are in your car and you find you are lost. You can’t look at your map because you are the driver. You ask your companion to open the map and see where you have to go. So your companion opens the map, unfolding it unevenly; struggling to get it open to see it. She finally has it opened and now has to look for the landmark to guide you further. Sounds complicated? More than you think. How much easier it would be if you had a navigation system in your car to guide you step-by-step. This is referred to as a GPS (global positioning system) navigation system. If you do not have one in your car and are looking to put one in it, you need to know about the system before you do so, this way you’ll know more about it so you get the right system for your needs.

To start with, you must know the basics of what runs GPS. Here are some facts to know:

• GPS receiver: The GPS receiver is what accepts the signal from the satellite and displays the results on a screen using either a display or graphic mode. These receivers can be programmed to provide various types of output. It really depends on your likes and what output you want.
• Global Positioning System: This is the whole system including the receiver and transmitter. The GPS is a collection of 27 orbiting satellites in space that operate to provide the information called for.
• Satellites: This is an object that revolves around a planet in a circular path. The path the satellite follows is referred to as an orbit. Satellites are custom built to perform certain functions. The only satellites that are not custom built are the GPS satellites. These are replicated.

The Global Positioning System (GPS) is made up of 27 satellites that orbit the Earth. There are actually 24 in space and three of them are spares in case the others should fail. Originally, GPS was established for the military, but it soon took off and became useful for civilians. Each satellite that GPS uses weighs about 4000 pounds and runs by solar energy. They circle the Earth at 12,000 miles and make two rotations each day. The orbits are arranged in such a way so that anywhere you go on Earth; there should be at least four satellites in view. The job of the GPS receiver is to locate four or more of these satellites, figure out the distance to each one, and use this information to know where the receiver is located. This process is known as trilateration.

When a GPS satellite transmits a long, digital pattern referred to as a pseudo-random code (a computerized random-generated number), a GPS receiver receives the signal and processes it. But the signal is not processed on time. In other words, there is a lag time between when the satellite sends on the signal and the time the receiver receives and processes the signal. This length of delay the receiver multiplies by the speed of light to determine how far the signal traveled from the satellite to the receiver.

In order for the measurement to be made accurately, the receiver and satellite has to use clocks that can synchronize as low as a nanosecond. To make this happen, the system would need to use atomic clocks (US Naval Observatory’s Master Clock), for both the satellites and receiver. The only problem with this idea is the atomic clock costs over $100,000. This is way too expensive of a proposition.

The GPS system was designed in such a way to overcome this problem. All GPS satellites use an atomic clock, but the receiver only uses a quartz clock. In order to work this clock correctly, the receiver has to constantly reset it. Basically, the receiver receives the signal, and adjusts for any inaccuracies it finds. The end result is one number that is used. And this time that is used is the correct time as set by the atomic clocks.

If having a GPS system sounds like something you may want to invest in, here are some companies that sell the products. Take a look and see what works for you:

• Pharos: Here is a company that sells a unit called a Traveler GPS 525. It is portable so it can go wherever you go. It helps you navigate streets and highways with great precision. It is voice-activated and allows you to make phone calls using VoIP form a WiFi hotspot. This particular unit sells for $550.
• Garmin: Garmin is a world leader in navigation and communication equipment. If you are looking for a GPS system, you’ve come to the right place. They have top of the line models to choose from. For example, they have the StreetPilot 530 that delivers preloaded maps with a touchscreen interface and a bright display. It sells for $642 but has many features and benefits that make it worth the price.
• OnStar: OnStar is the most famous GPS supplier all of. They have systems built into cars. They install it at the factory so you have it when the car is bought. The system is well designed and found in many vehicles. Currently, only GM vehicles have this system. They have plans that start at $16.95 a month.
• TomTom: TomTom has a complete line of GPS systems that can probably suit you and your budget. One such product is the TomTom GO 910. This one is easy to use and has maps of Europe, the US, and Canada. All directions are voice-activated and include actual street names.

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