work of 24 satellites run by the U.S. Department of Defense. Any- one with a GPS receiver can receive his or her satellite position and thereby find out where he or she is. Vehicle-positioning applications can be used to deliver several services including remote vehicle diagnostics, ad hoc stolen vehicle tracking, and new rental car fleet tariffs. The SMS is ideal for sending GPS position information such as longi- tude, latitude, bearing, and altitude. GPS coordinates are typically about 60 characters in length. GPRS could alternatively be used. Remote LAN Access When mobile workers are away from their desks, they clearly need to con- nect to the LAN in their office. Remote LAN applications encompass access to any applications that an employee would use when sitting at his or her Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. GPRS Introduction GPRS Introduction desk, such as access to the intranet, his or her corporate e-mail services such as Microsoft Exchange or Lotus Notes, and to database applications running on Oracle or Sybase. The mobile terminal such as a hand-held or laptop computer has the same software programs as the desktop on it, or cut-down client versions of the applications accessible through the corpo- rate LAN. This application area is therefore likely to be a conglomeration of remote access to several different information types-e-mail, intranet, databases. This information may all be accessible through Web browsing tools, or require proprietary software applications on the mobile device. The ideal bearer for remote LAN access depends on the amount of data being transmitted, but the speed and latency of GPRS make it ideal. File Transfer As this generic term suggests, file transfer applications encompass any form of downloading sizeable data across the mobile network. This data could be a presentation document for a trav