The best way to select a GPS Receiver (2)
How GPS Works
GPS stands for Global Positioning Method, which pinpoints places on land and sea utilizing a network of 24 orbiting satellites operated through the United States Department of Defense. Satellites are information transmitters, beaming waves of details down to earth. GPS technologies captures a combination of 3 or much more satellite-transmitted waves to triangulate the GPS receiver’s placement on earth.
Early on, a technique of "selective availability" prevented private citizens from full access to GPS technologies, limiting the precision of consumer-owned receivers to 100 meters. But in 2000, the U.S. government removed selective availability, substantially improving GPS precision.
WAAS: A Huge Improvement
In 2003, the government opened the door for a lot more improvements in precision by producing the Wide Area Augmentation Technique (WAAS) accessible. Originally created as an aid to aircraft navigation, this uses ground-based stations to supply GPS signal corrections. A WAAS-enabled GPS unit can achieve place precision of far better than three meters beneath perfect situations. This can be particularly true if the unit has a high-sensitivity processor chip this kind of since the SiRF Star III.
Nonetheless, be aware that real-world circumstances are hardly ever "ideal." Tree cover, canyon walls and tall buildings can all block signal reception, and moving satellites aren’t often in optimal place. So it is advisable to expect precision of 20 to 30 feet, even while using the greatest WAAS-enabled GPS. If you’re an international traveler, know that WAAS is currently functional only in North America.
Benefits and Limitations
GPS technologies functions day or night, rain or shine. Theoretically, a high-end GPS product can aid you come across your way as a result of an old-growth forest inside the dead of night. To perform so, nevertheless, calls for an exceptional antenna that may capture reception beneath heavy tree cover. Night travel also requires a backlit display, and backlighting speedily drains battery power.
This serves like a reminder that though a GPS device enhances your navigational abilities, it ought to NEVER be regarded as a replacement for a map and compass and the knowledge of how you can use them. The fact remains that a GPS receiver is an electronic device: Batteries run out; electronics break down. Generally go prepared while using "old technology" of your compass and map.