The document discusses interfacing a GPS modem with an Arduino Uno board to display location information on a 2x16 LCD. The GPS modem receives satellite signals, decodes them, and sends data like latitude and longitude in string format using the NMEA standard over serial. The Arduino program filters the NMEA data received and displays the location on the LCD.

1. GPS Modem interfacing with
Arduino UNO

2. Project Overview
Arduino UNO
Board
2x16 LCD
GPS
Modem

3. GPS Modem
 GPS Receiver receives the information in string format,
transmitted by Satellites and uses this information to calculate
different parameters between it and satellites. With
information from satellites, a GPS receiver can fix its location
on the ground from the known position of the satellites.
 The GPS modem has an antenna which receives the satellite
signals and transfers them to the modem. The modem in turn
converts the data into useful information and sends the output
in serial RS232 logic level format. The information about
latitude, longitude etc is sent continuously and accompanied
by an identifier string.

4. NMEA Data Format
 GPS receiver communication is defined within this
specification. Most computer programs that provide real
time position information understand and expect data to
 Each sentence begins with a '$' and ends with a carriage
return/line feed sequence and can be no longer than 80
characters of visible text. The data is contained within this
single line with data items separated by commas. The data
itself is just ASCII text and may extend over multiple
sentences in certain specialized instances but is normally
fully contained in one variable length sentence.

5. GPS Modem Output Sentences

6. GPS String Format

7. Block Diagram
Arduino
UNO

8. Working of the System
 For displaying the location over LCD, the GPS modem
and the 2x16 LCD is attached with Arduino UNO board.
 The GPS modem receives signals from satellites, decodes
the signals and send the data in ASCII string format in
NMEA standard over the serial port of the
microcontroller.
 The microcontroller is programmed to filter the data
received through its serial port according to NMEA
standard and displaying the desired data over the LCD
attached to it.