Portable automobile GPS units are the ultimate GPS to use. Auto GPS has either voice or screen or both visual and audible turn by turn directions displayed on a large and bright screen for easy navigation. One of the best features about auto GPS units is that auto GPS unit users do not have to subscribe to an additional service for the devices to work. Auto GPS is becoming more and more popular in America and abroad. Auto GPS systems are also known as navigation systems. If traveling outside of your car, handheld GPS units display your coordinates over a highly detailed map which will accurately pinpoint your location no matter how far you may be hiking, or trail riding in the great outdoors away from camp or your vehicle.