Initially GPS is used for only Defense department of United States but later on it is being more mainstream, now it is being used for general purpose too. GPS is a very powerful tools which works 24*7*365 continuously. It's location tracing power is highly accurate.
There are 24 satellites moving in the 6 orbit planes (four satellites in each plane) continuously signaling signals in 340 nanoseconds. There are two levels of services provided by GPS.
Standard Positioning Service
The standard positioning service is a positioning and timing service, which will be provided on the GPS L1 frequency that contains a coarse acquisition (C/A) code and a navigation data message. SPS is continuous available around the world to all GPS users without no direct charges. SPS provides a great accuracy in positioning of 100 meters (95 percent) horizontally and 156 meters(95 percent) vertically and time transfer accuracy to UTC within up to 95 percent (340 nanoseconds).
Precise Positioning Service
PPS is a highly accurate military service which provides the services of highly accurate military positioning, velocity and timing service continuous available only for U.S.A. military and authorized U.S. P(Y) code GPS users in all over the world. PPS provides a predictable positioning accuracy of at least 22 meters (95 percent) horizontally and 27.7 meters vertically and time transfer accuracy to UTC within 200 nanoseconds (95 percent). PPS is transmitted the data on the GPS L1 and L2 frequencies. It was designed earlier for the prime use of United States military and denied to the unauthorized users, but later it is being used by non-federal government, civil use of PPS in the country and beyond the country with some conditions like:-
Now days GPS is being used in mobile field also. It is being more and more capable. The uses of GPS is increasing very rapidly. Let's see some capabilities of GPS in mobiles and vehicles.