ABSTRACT:
In this paper, some of the ideas of positioning and navigation using GPS (Global Positioning System) where explored, GPS is a
satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. This
paper provides the use of a handheld GPS receiver in the areas of precise positioning, mapping locations, navigating across the
mapped locations very easily. The purpose of this paper is to showcase the experiences that incurred in designing a positioning and
navigation system (with the aid of a 12 parallel channel handheld GPS), which can be used as a moving compass, steering to any
mapped destination, providing the information about near by places, tourist attractions, petrol bunks etc. The Magellan 310 handheld
GPS which is being used for developing the proposed system allows users to connect to a personal computer through RS-232 Serial
Interface and the protocol used by the device for communication is NMEA 0183, (National Marine Electronics Association). It is an
American national regulatory body, which, among other things, sets standards pertaining to the interfacing of marine electronic
devices. This NMEA 0183 Protocol transmits data to the connected PC every 1 second, this data has to be interpreted and filtered
accordingly to get the needed information from the GPS device. This paper provides a case study in the process of designing such a
system and its limitations in the era where through distance measurements from a few more satellites, the receiver can determine
the user's position and display it on the unit's electronic map. It also portrays the implementation details and their results obtained
and along their pros and cons when compared with the other existing positioning and navigation system designed for basic handheld
GPS (without having advance features like provision for electronic map etc. in the device), It also addresses some of the
enhancements that can be accomplished in the designed system. This paper is organized by providing a brief introduction to GPS
technology and then dealing with hardware description & NMEA Messages along with a case study implementation detail of the
system, its features and possible enhancements in the system.