Some of the most important features to look for when buying a GPS (Global Positioning System) navigation device are:

Text to speech
Some GPS devices can tell you names of streets you are approaching. If you want to know which street you are on, or which street to turn into withoutytaking your eyes off the road, then this is a very handy feature.

Traffic Channel Data
Some GPS devices can pick up signals from live traffic channels, helping you to avoid traffic incidents. It can save you alot of time by warning you about traffic jams, road closures and roadworks.

Bluetooth
This is a useful feature if you would like to make hands-free calls on your mobile via the GPS device.

Big Screen Size
Go for a larger screen if possible – 4.3 inches is ideal. If portability is essential (ie if you will be on foot or without power for extended periods of time) having a smaller screen will help conserve battery life.

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UNDER $300
Garmin Nuvi 250
Excellent value at $230. Weighs less than 150g and easily fits in your pocket. 3.5inch screen with 5 hour battery life. Interface is easy to navigate and selecting a destination is very simple.

See also:
TomTom One – $280, not bad value for a budget GPS unit

UNDER $500
Uniden Trax 430
Has text to speech and an easy to use interface at $350.

See also:
Magellan Roadmate 1412 – $380, works well with decent features for the price.
Garmin Nuvi 265 WT – $470, pricey but worthwhile to get features such as bluetooth and live traffic data.
TomTom XL – $380, same as the TomTom One but with a larger screen.

OVER $500
Mio Moov370
Has all the features with 4.3inch screen, bluetooth and live traffic support for $530.

See also:
Magellan Maestro 4250 – $570, a very polished unit at a respectable price.
Pioneer AVIC-F500BT – $900, pricey but integrates with your car stereo with a huge 5.8inch screen.

GPS (Global Positioning System) navigation uses a network of satellites that enables somebody with a GPS device (receiver) to pinpoint their exact location. Hence it is also referred to as satellite navigation, or “satnav“. The satellite network, which belongs to the US Department of Defence, is available to anybody with a compliant GPS device.

There is a huge range of GPS technology for sale, and before you buy it is important to know what sort of GPS unit will suit your needs. GPS receivers come in a variety of configurations.

In Car GPS Satellite Navigation (SatNav)
This provides you with the ability to track your position whilst in your car. Most modern in car GPS navigation devices have colour displays with mapping software to show you how to get to a given destination from your current location. The devices also allow hands free navigation, often with the aid of voice commands and easy to see visual gps maps.

Handheld GPS
Handheld GPS receivers are GPS devices that fit easily in the hand and can be kept with you as you track your position. Most handheld GPS devices can track where you have been or at least certain points (waypoints) along the way. They can also help you to find exact map grid references.

Another type of handheld GPS is in the form of an add-on or plug-in for a PDA (a handheld computer such as a pocket pc, palm etc) that allows the use of GPS positioning in software running on the handheld computer.

Personal GPS / Sports GPS
Also available are personal GPS devices that are very small (slightly larger than a 50c piece) that will use GPS as a way to track your position and also use GPS satellite time to give you feedback on running or walking speed, distance, speed, altitude and the like. They come in a variety of types designed for specific uses.

Mobile Phone GPS / Cell Phone GPS
Many mobile phones now have GPS tracking equipment and software built in. In the future mobile GPS facilities will allow mobile services and applications that help you make decisions based on your location and movements.

Bluetooth GPS Receivers
This is a GPS accessory that allows you to wirelessly run a GPS receiver for your handheld computer or PDA.

GPS Brands
Popular brands for GPS units include Garmin, Magellan, Tomtom and Navman. There are also many other GPS brands to choose from and the internet provides an ideal way to search for and compare brands, features and prices. Online prices are generally cheaper.