GPS+Takes+A+Global+Position+In+The+Portable+Market

 -GPS has become an essential part of various commercial and personal products that rely on location, position, and navigation. -The GPS system is composed of a constellation of 24 operation satellites. -It proved invaluable initially in the Gulf War and in all military endeavors since then many times over. Not only that, GPS has become an essential part of many commercial and personal products that rely on loca- tion, position, and navigation. -And many low-cost GPS radio chips and navigation receivers have become available to everyone. In fact, one standout trend is to add GPS to as many handheld products as possible. -each satellite transmits what is called ephemeris infor- mation, which defines precisely where it is in orbit. -The position information is in the form nearby DGPS radios. of latitude and longitude. -Latitude and longitude data requires three satellites. Altitude and speed calculations require four satellites. -The FAA built about 25 ground stations around the US, some on the coast, with precisely known positions. -These stations monitor the GPS satellites and determine errors -GPS works with cell phones -specifically those CDMA headsets used with Verizon and Sprint Nextel systems, contain a GPS receiver that helps to meet the government's mandate for E911 capability on all cell phones =a cell phone's position can be accurately determined if a 911 call is made from it, enabling emergency personnel to quickly respond and locate the caller even if no directions are provided -AT&T and T-Mobile don't use GPS. -A-GPS- -brings the cell-phone network into the picture to provide location information when the cell phone goes inside, at which point the antenna cannot see the satellites. In the network, a location server monitors the satellites and knows the precise location. That server communicates the information to the cell phone via the network. -GCF is a partnership between net-work operators and mobile handset manufacturers that provides an independent program to ensure global inter- operability for 2G and 3G phones. -