FINAL YEAR PROJECT 2 (WEEK 5): GPS Interfacing

Objectives:

1) To construct circuit of GPS interfacing and display on the LCD.

2) To build a program using C++ language 

Method:

1) using Proteus 7 Professional software to construct circuit

2) using KeilVision4 to write the program

The program has been written and compiled. The HEX file is loaded to the circuit. The simulation is running to demonstrate the system operation. Below is the circuit which had been running the program:

GPS is used to locate the accident happens in this project. It depicts the use of GPS module/receiver to find latitude and longitude of its location. The data obtained from GPS receiver (GPGGA sentence) had been processed by the microcontroller to extract the latitude and longitude values. The serial data is taken from the GPS module through MAX232 into the SBUF register of 8051 controller which refers to serial interfacing.  By using the Serial Interrupt of the controller, the serial data from the GPS receiver is taken. The data consists of a sequence of NMEA sentences from which GPGGA sentence is identified and processed. The first six bytes of the data received are compared with the pre-stored ($GPGGA) string and if it is matched, the only data is further accounted for besides the process is repeated again otherwise. From the comma delimited GPGGA sentence, latitude and longitude positions are extracted by finding the respective comma positions and extracting the data.

Conclusion: 

This week I learn how to do the program for GPS interfacing which linked with the LCD display. I learned that the program need to start by declared the input pins that had been used in the circuit. The GPS module continuously transmits serial data by using RS232 protocol in the form of sentences according to NMEA standards. The latitude and longitude values of the location are contained in the GPGGA sentence by referred NMEA format. In this program, these values are extracted from the GPGGA sentence and are displayed on LCD.