GPS
Short for Global Positioning System, a worldwide MEOsatellite navigational system formed by 24 satellites orbiting the earth and their corresponding receivers on the earth. The satellites orbit the earth at approximately 12,000 miles above the surface and make two complete orbits every 24 hours. The GPS satellites continuously transmit digital radio signals that contain data on the satellites location and the exact time to the earth-bound receivers. The satellites are equipped with atomic clocks that are precise to within a billionth of a second. Based on this information the receivers know how long it takes for the signal to reach the receiver on earth. As each signal travels at the speed of light, the longer it takes the receiver to get the signal, the farther away the satellite is. By knowing how far away a satellite is, the receiver knows that it is located somewhere on the surface of an imaginary sphere centered at the satellite. By using three satellites, GPS can calculate the longitude and latitude of the receiver based on where the three spheres intersect. By using four satellites, GPS can also determine altitude.
GPS was developed and is operated by the U.S. Department of Defense. It was originally called NAVSTAR (Navigation System with Timing and Ranging). Before its civilian applications, GPS was used to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces.
GPS has applications beyond navigation and location determination. GPS can be used for cartography, forestry, mineral exploration, wildlife habitation management, monitoring the movement of people and things and bringing precise timing to the world.
Read Also:
- NC
A type of network computer designed to execute Java programs locally. NCs do not contain any storage devices, so they must be connected to a network server that holds the data to be processed. However, unlike thin clients and Windows terminals, NCs do have a microprocessor so that they can execute programs locally.
- NCP
Acronym for NetWare Core Protocol. NCP, or NetWare Core Protocol is the file-sharing protocol between server and client(s) on a Novell NetWare network. NCP controls many requests to the file and printing system, along with login requests. NCP is a client/server LAN protocol. Clients (or workstations) send NCP requests, which are sent via IPX or […]
- NDIS
Short for Network Driver Interface Specification, a Windows device driver interface that enables a single network interface card (NIC) to support multiple network protocols. For example, with NDIS a single NIC can support both TCP/IP and IPX connections. NDIS can also be used by some ISDN adapters. NDIS includes a protocol manager that accepts requests […]
- NDMP
Short for Network Data Management Protocol, a protocol pioneered by Intelliguard and Network Appliance that defines a common architecture for the way heterogeneous file servers on a network are backed up. The protocol will allow the creation of a common agent used by the central back-up application to back up different file servers running different […]
- NDR
Short for Non-Delivery Receipt, NDR is an e-mail related acronym. When an e-mail message is composed and sent to an invalid e-mail address the receiving, or in some cases the sending, e-mail server attempts to send an NDR to the sender of the e-mail message, to inform them that the e-mail address used is invalid.