In 1973 the U.S. Department of Defence launched the Navstar GPS network. This consisted of 24 satellites orbiting the earth every 12 hours and five ground stations. This positioning system was made available for public use. With this capability, consumer location devices were produced to accurately determine location and other data such as current and average speed, directional heading, and elevation. These GPS devices need an unobstructed view of at least four satellites to provide a reliable 3D fix.

The GPS receiver overlays this location data onto map files stored on the unit, to give a current position on the map as well previous track. The receiver constantly recalculates position, giving real time position.

A typical GPS device contains:

• 12-channel receiver - the quality of the receiver determines how long it takes the device to acquire a 3D fix.
• Antenna to capture satellite signals - positioned to get a clear view of the sky.
• CPU to process the data and overlay on maps
• DVD Hard-drive - where maps on DVD’s or available online are uploaded and stored. Some cheaper units do not upload the maps, but reference them off the DVD or CD.
• Display Screen - mostly color with handheld units using black and white
• Voice Interface - more advanced units

How The GPS Device Gets A Fix

The first time you start your GPS device, its data store is blank so needs a to collect satellite information to determine your position. This is known as a cold start. Some units only take 30 to 45 seconds to acquire a 3D fix during a cold start, while others can take several minutes. Subsequent position updates only take 3 to 4 seconds. If you go out of range from losing line of sight, such as passing behind a large building or through a tunnel, a good receiver will instantly recover, whereas weaker units will require more time to reacquire a 3D fix.

How Different GPS Navigation Units Differ

Location of Antenna - A factory installed in-dash unit antenna is integrated into the dashboard where it has an unobstructed view of the sky. Many portable models have a suction-cup-mounting device to position the device on the windshield. Add-on antennas are also available. Regardless of the type of unit and antenna, the important thing is to keep the antenna visible to the greatest area of sky possible. Choose a unit where this can be done AT THE SAME TIME as being able to maintain a clear view of the screen.

Screens and Display - important to check how bright these are, and if they are clearly visible from the mounted position in bright day light. Onboard navigation systems are generally color screens, and portable units are black and white to save power. Larger screens and integrate better with other vehicle electronics.

Input Buttons - most enroute buttons are on the display screen. Ensure these are easy to use when driving; that is they are big enough and colored sufficently to see without causing a driving hazard.

Map Media - Earlier models were CD-based, requiring multiple discs to cover the entire United States. Newer in-dash systems are DVD-based; only 1-2 DVD’s required for an entire country of maps.

Cost - In-dash systems are usually more expensive than portable counterparts. Aftermarket in-dash models usually require professional installation and can be just as expensive as the factory models.

Upgrading - always check how easy it is to upgrade the firmware and maps on your GPS unit. Some units detach a portion to be connected to the computer via USB, whereas others are done using a DVD. Those units which can be upgraded online, are much more convenient.

Added Features of GPS Units

Apart from giving you a current position, a number of GPS navigation devices can give you:

• A track of where you have been - the number of tracks and waypoints stored varies from unit to unit. You may also want to save on part of a track for future use.
• A path from your current position to your destination
• Maintain commonly used navigation paths for reuse.
• Points of Interest - user sets the types of points of interest, such as tourist, bank ATM, petrol stations, historical, accommodation, restaurants etc.
• Real time traffic reporting to avoid traffic delays. This can also include road works.
• Voice recognition to receive destination instructions, and voice guidance to give driving instructions
• Weather updates
• Street name navigation - instead of just turn left 200m it was say ‘Turn left into Stanley St’
• Integrated Multimedia players - MP3 players, image viewers, and audio books.
• Onboard or Portable GPS Navigation

The downside of onboard GPS Navigation units are susceptible to theft; and you cannot take them with you to use in other vehicles or when travelling abroad. Portable units, such as the Garmin StreetPilot 2720, can be used in multiple cars; being easily moved from car to car. Depending upon the power supply and portability, portable and handheld units can be taken when travelling or used on cycles, boats, private aircraft etc.

For more information on Go-Reviews.com Car Electronics Section.

Nicola Carr - Nicola is a technology strategist and publisher of Go-Reviews.com. She provides product reviews and buying guides on a wide range of technology. Nicola is also a feature writer for Electrosmart Digital Publishing and RichMediaMix demonstrating how technology is integrating into business and media.

I desire that the following article will help you to better understand this topic. For the car fan there is nothing as satisfying as a car that has all of the cutting-edge accessories installed. With these various accessories you can get the premium service that you have always dreamed about. One item that many car owners want is a great look sound system. To find this you will sometimes need to go and see multiple car audio stores. As this can sometimes be a hassle you can utilize the internet as a research mechanism.

When you type in the words car audio stores your favorite search engine will showing many different pages that are filled with links that you can access. Going into these links will erupt the assorted car audios these stores have in stock. You can use their Warehouse or shop section to see the unlike car audio that you like. Now even though you are initially going to do some explore the cyberspace may tempt you to buy some of their trade goods from these car audio stores. To void this you should know a few facts about different car audio systems. With this info you can get good items that will help your car audio to sound actually clear and nice.

Once you have looked at the assorted car audios that you can bargain you should check out a few car sound reviews to see what other customers have to say about the another car audios. Their comments can help you to nullify car audios that will give you many problems. These facts can actually come in handy at the assorted car audio stores that you will need to visit. So what should you do once you reach these assorted car audio stores? Well the first thing that you should do is to browse the diverse systems that are available.

You should find a sales Assistant who can help you out and answer various questions that you may have regarding the different car audios that you see. Among the many questions that you can ask should be the specifications of these car audios and the be range of each. You should wait until you have reached a few more car audio stores before you decide what types of car sound system you wan to have installed in your car.

Once you have brought your car sound system all that remains is to follow the operating instructions and set up the system. As soon as the system is wholly fitted in you should give this new car audio a test run and delight the great sound poring into your car. Thank you for Taking you time to read through this information if you’re concerned in gathering more knowledge please continue to search this site.

Michael Malega presents several car audio stores articles for your information. You can visit Michael’s World Wide Web site here car audio stores

In the United Kingdom, a law has just been passed which forbids drivers to use mobile phones whilst on the move. In fact, this is not quite true as the law has been around for some considerable time. Yet the authorities are cracking down on the use of mobile phones on the move and making it a more serious offense.

Up until February 1st, using a mobile phone on the move could lead to a fine of approximately $60. This was hardly a deterrent and people could be seen at all times using the telephone. There have been a number of instances when pedestrians have been killed because of drivers using mobile phones and losing control of their vehicles. The 60-dollar fine was not much of a deterrent for most people. Therefore, on the 1st of February the fine has been increased to $120 together with three points endorsement on the driving license.

This is thought to be able to produce a situation where people will think twice before using a mobile phone. Yet whether this will prove to be useful overall is debatable. The mobile phone has become an essential item for use at all times of the day and even at night.

The days are long past when the only way we could communicate with other people was if we were at home and near our land line phones. Now the mobile phone is useful for general communication and for more “important” communications involving the safety of children, loved ones, and relatives.

The risk of using a mobile phone only becomes noticeable at times when authorities such as the law enforcement are nearby in order to see the crime being perpetrated. The vast majority of car, and other vehicle, drivers will know that they are safe most of the time to use their mobile phone without being caught.

Eric Hartwell oversees “The World’s Best Homepage” intended to be a user-generated resource where YOUR opinion counts. Anybody can contribute and all are welcomed. Visit us to read, comment upon or share opinions at the worlds best homepage or submit or use content at free content resource.

Its consumer nature to want to find the highest quality product at the lowest price. When searching for car audio there are a few places where you are guaranteed to find cheap car CD players. All of these are online venues that have netted the searching consumer an awesome cheap car CD player. When I say cheap I’m not referring to the quality, but the price of the car CD player.

The first place you should check out online should be Froogle. Froogle is Google’s online product search engine. When you enter a a search query into the search bar at Froogle, Google will send it search engine spiders over the internet finding prices, descriptions, and pictures of all the cheap car CD players it can find. The best part about it is you can organize the results to display from lowest priced to highest price. Thus saving you a ton of time.

Go to http://www.froogle.com!!

The second place that you should search for cheap car CD players is on CraigsList. This is an online database of classified ads organized by city. CraigsList is the absolute best place to find gently used cheap car CD players. When you find an ad that looks interesting, contact the seller and set up a meeting. This is another advantage of using Craigslist. You actually get to see and touch the product before you buy. If you can’t find a cheap car CD player anywhere else you will be able to find one on CraigsList.

Go to http://www.craigslist.org!!

The third place you want to look for a cheap car CD player would be Ebay. Ebay has some of the best deals on new and used car audio on the internet. You must be careful on Ebay as some sellers are crooks. Always check out the sellers feedback rating before you do any business with them. I would recommend you look elsewhere if their feedback rating is under 90%.

Go to http://www.ebay.com!!

Using these three internet resources you should be able to find a great deal on cheap car CD players. We’re talking brands like Sony, Pioneer, Alpine, and Clarion. Whatever kind of cheap car CD player you want you WILL find it!!!

The author Garland Robinson is a serious car audio enthusiast. He has installed systems in multiple cars and attended sound competitions and car shows.

His extreme passion for this hobby has driven him to create a website based solely on car audio.

Check it out @ http://www.onlinecaraudio.info

The mp3 player has now become a stable part of many people’s lives. Not only are they small and versatile, but also they provide the user with hours of music listening time without having to keep changing CD’s or tapes. But just how can I use my mp3 player in my car?

In this article we will look at some different ways that you can now use your mp3 player in your car and so no longer will you need to worry about carrying all your favorite CD’s in the car in the future. Plus you have the added benefit of knowing that you can remove your mp3 player from your car and take it with you.

Nearly all mp3 players will have a port in which you connect your headphones. But in order for your to play your mp3 player in your car you will need to find a way of connecting this to the head unit using the headphone port. Below is one method that you may want to try.

Auxiliary In

This method will provide you with the best audio quality possible, in fact it is just about as good as the audio produced by a CD. Numerous head units (radios) in cars today have a front auxiliary input (known as the Aux-In) that allows you to plug directly from your mp3 player into the head unit. You will find that most Sony head units have this feature on all their entry-level units.

However there are other methods that you may want to try if you do not happen to have a head unit that has an auxiliary in feature with it. Below we look at some other ways in which you should be able to play your mp3 player in your car in the future.

Cassette Tape Adapter

This device is available for around $10 and can be found in most electronic stores. It provides you with an easy and straightforward method of hooking up an external device such as an mp3 player to your car stereo system. All you have to do is place the cassette tape in to the car’s tape player and then attach the other end to the headphone or line out jack situated on your mp3 player.

However, there are a number of drawbacks to this method. Firstly you need to have cassette player in your car (which unfortunately is becoming much less common in more modern cars) and secondly you will often the sound quality is reduced.

FM Transmitter

This system will transmit an audio signal of the your mp3 player to a specified FM frequency when it is plugged into the FM transmitter. What happens is your FM stereo in your car is then able to pick up the sounds as if it was actually receiving a regular FM broadcast from a radio station.

So as you can see there are plenty of ways to answer the question how can I use my mp3 player in my car. All you need to decide is which one you feel best suits your particular needs.

For more information on ipod stereo accessories try visiting http://www.streamingaudio101.com where you will find tips, advice and resources about topics such as the best ipod case.