A small GPS-based unit that is designed for handheld operation or windshield mounting in a vehicle. Handheld units have small screens, typically up to 3", while vehicle units reach 5". Handheld GPS devices are geared to different applications, such as hiking, cycling and sports.
Devices for vehicle use offer many of the navigation features of in-dash units, but do not have the A/V functions such as the CD, DVD and MP3 playback found in after market products. Portable GPS units can run for several hours on their rechargeable batteries and plug into an AC adapter or vehicle power outlet when required.
One disadvantage of portable GPS units is their inability to track satellites when there is no line of sight such as in deep valleys, on streets with tall buildings or lower levels of bridges (see in-dash navigation for more details). See GPS, GPS augmentation system and Google Navigation.
This amazing unit from Magellan can be used in a car or handheld when walking. It offers most of the navigation features of in-dash units, including text-to-speech playback of street names.
This Garmin unit includes topographic maps for hikers as well as high-tech treasure hunters (see
Garmin's Forerunner sports watch provides much greater accuracy than a pedometer and can help runners find their way home in unfamiliar territory. It also attaches to a heart monitor via a wireless connection. (Image courtesy of Garmin Ltd., www.garmin.com)
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