A handheld GPS is a small electronic device that uses a global positioning system to determine an exact location on Earth. Handheld GPS units are commonly used for navigation, geocaching and outdoor activities like hunting and fishing. A wide variety of handheld GPS units are available for sale by many manufacturers including Garmin and Magellan.http://www.bestbuy.com/site/Outdoor+GPS/Handheld-GPS/abcat0301001.c?id=abcat0301001

Using at least three orbiting satellites, GPS systems are able to calculate the distance between the GPS receiver and each of the satellites to determine a location within several meters. GPS was originally developed by the United States Department of Defense and primarily uses U.S. Military satellites.http://www.gps.gov/

Similar to the wide selection seen in cell phones, handheld GPS units are available with numerous features. Lower-end models feature a standard black and white display, whereas higher-end models may have a large, color touchscreen. Many include built-in maps and most allow specific locations to be saved on the device allowing the user to re-visit that location later. Most handheld GPS units come with on-board memory, which can vary in size. Many also allow the memory to be expanded using a memory card.http://www.bestbuy.com/site/Outdoor+GPS/Handheld-GPS/abcat0301001.c?id=abcat0301001

Handheld GPS units are similar in size to a cell phone or PDA with a rubber, plastic or metal casing. As GPS units are often used outdoors, many are designed to be rugged and water resistant. Other features may include a calendar, compass, altimeter and two-way radio.http://www.bestbuy.com/site/Outdoor+GPS/Handheld-GPS/abcat0301001.c?id=abcat0301001