Compact and Powerful
| This new GPS unit is one of the smallest on the market, measuring just 1 7/8" w x 2 5/8" h x 9/16" thick. It comes with an attached 5' cable with a suction cup on the cable designed to hold the GPS against the windshield or on the dash for optimum performance. Just plug the other end of the cable into the USB port of your laptop PC. It is best to avoid rapid and far-ranging temperature extremes, bringing the GPS indoors when not in use, just as you would a cell phone. The yellow reflective casing helps reduce high temperatures while on the dash. | (Phone shown for size comparison only) |
Getting Started Is Easy
Plug the Earthmate GPS LT-20 into the USB port of your laptop PC. The low-power chipset draws power from your laptop, meaning no GPS batteries are needed. Install the Street Atlas USA 2005 software, and load the entire second data disc onto your hard drive if you want. The software also includes over 4 million places of interest. Place the GPS as close to your front windshield as possible, ideally using the enclosed suction cup on the attached cable to hold the GPS against the glass. Click on the software GPS tab and you'll see your position updated in real time on the maps as you drive. There are many custom GPS options included within the GPS tab.
Abilities at a Glance
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What Is WAAS?
WAAS stands for Wide Area Augmentation System and is a system of satellites and ground stations that provide GPS signal corrections. As is true of the GPS satellites, there is no extra charge or equipment required to take advantage of WAAS. Because the new Earthmate USB GPS is WAAS-enabled, it is possible where WAAS is available to experience accuracy of under three meters for the majority of tracking time.
How WAAS Works
The system consists of roughly 25 ground reference stations positioned across the United States. These ground stations monitor GPS satellite data. Two master stations are located on each coast and these collect data from the reference stations and create a GPS correction message. This correction takes into account GPS satellite orbits, clock drift, and signal delays, typically caused by atmospheric conditions. The corrected differential message is broadcast through one of two geo-stationery satellites or satellites with a fixed equatorial position. Any WAAS-enabled GPS, such as the Earthmate USB GPS, is able to read this signal and benefit from the enhanced accuracy.
WAAS Performance Considerations
As is true for all GPS usage, the location and environment of the user will cause variability in WAAS performance. For instance, the position of the satellites over the equator make it difficult to receive the signals when mountains or trees obstruct a clear view of the horizon. Therefore, it is safe to say that WAAS provides the best performance in open-area situations. Unlike DGPS (differential GPS), WAAS does not require additional receiving equipment.