While GPS technology doesn't require a great deal of space, the software that adds the functionality expected by the consumer does. Software, once created, gets improved by getting smaller. Not all functions are needed by all consumers and these are the facts that have resulted in smaller GPS units that are allowing more mobile GPS technologies.
A GPS unit only requires a radio emitter and a clock to work. The emitter sends the time reading of the clock to the satellites overhead. The satellites calculate the amount of time it took for the radio signal to reach them and figure the distance from that. Three or four satellites compare their locations and the amount of time the signal took to reach them. They are then able to arrive at a location within about six inches depending on the accuracy of the unit's clock.
If the location is meant to be transmitted to a third party, the mobile GPS unit can be small enough to clip to a pet's collar or fit into a cell phone. It can make an expensive watch virtually impossible to steal or take up such a small space that a PDA has room left over for some pretty nifty software.
The portability of a mobile GPS device allows a consumer to come up with different uses for it. Besides plotting navigation or tracking objects and living things, it can use the data as information in applications. Recently, a small camera with a mobile GPS unit was released. It keeps track of the places where the pictures were taken and can be used to create digital maps using the photos to mark locations. This is a creative step forward in using GPS technology.
Though larger, laptops are just as portable as other types of mobile GPS devices. GPS attachments are easily added to laptops with a USB cable. Different types of software can be used for a variety of reasons. A laptop GPS unit can be used in a car to navigate a route and then store the information for business reports later.
Before taking a mobile GPS to use on a flight, check with the airline. Many allow a GPS at some times during the flight, whereas others do not allow it at all. A few airlines include a GPS locator in the seat back TV.
Soon, many more uses for the mobile GPS device will be developed and a few years from now we will wonder how we managed without them.