How To Obtain Latitude and Longitude from a GPS TTL Module

GPS TTL Mini is a high gain GPS Receiver The on board 3V3 to 5V level convertor enable us to directly interface with normal 5V Microcontrollers. The module is made with ultra small High gain third generation POT (Patch Antenna On Top) GPS module. There is no prior configuration required; just power the module with 5V, and your data (NMEA 0183) is ready at TX pin.
It has a very compact and easy to integrate design with the ultimate tracking performances. It is also ideal for those who wish to plug-and-play GPS receiver module into their small form factor design. It can be directly connected to Microcontroller’s UART.

The GPS chipsets inside the module are designed by MediaTek Inc., which is the world’s leading digital media solution provider and largest fab-less IC company in Taiwan. The module can support up to 66 channels. The GPS solution enables small form factor devices. They deliver major advancements in GPS performances, accuracy, integration, computing power and flexibility. They are designed to simplify the embedded system integration process.

To determine the location of the GPS satellites two types of data are required by the GPS receiver: the almanac and the ephemeris. This data is continuously transmitted by the GPS satellites and your GPS receiver collects and stores this data.The data received is just ASCII text and varies in precision. Every sentence begins with a ‘$’ sign, has about 80 characters and ends up with a carriage return/line feed sequence. Sentences are mostly framed in single lines (may run over to multiple lines sometimes) and the data items in each sentence are separated by commas.As the module provides current time, date, latitude, longitude, speed, altitude and travel direction / heading among other data, so it can be used in a host of applications, including navigation, tracking systems, fleet management, mapping and robotics.

Features:

MediaTek MT3329 Chipset, L1 Frequency, C/A code, 66 Channels
TTL asynchronous serial interface
5 VDC supply @ 55 mA (typical)
Data output Baud rate: 9600 bps(Default)
Standard NMEA0183 output format
Low Power Consumption: 55mA @ acquisition, 40mA @ tracking
High Sensitivity, -165 dBm, TCXO Design , superior urban performances
Position Accuracy: <3.0M 2D-RMS
DGPS (WAAS/EGNOS/MASA/GAGAN) Support
Multi-path Compensation ; E-GSM-900 Band Rejection
Cold Start is Under 36 seconds (Typical)
Warm Start is Under 34 seconds (Typical)
Hot Start is Under 1 second (Typical)
Max. Update Rate : 10Hz (Default: 1 Hz)

Specification:

PIN Diagram:

GPS TTL Mini PIN descriptions are as below

Layout:

How toTest:

1. Test your GPS TTL Mini using PC:

Here a sample test is shown using RhydoLabz USB to Serial Converter (5V/3V3). When USB cable is connected to the converter, “PWR LED”(Blue) on the top of converter module and “PWR LED”(Blue) on the top of GPS module glows , which shows the power indication.
The connection details of GPS module with USB to Serial Converter (5V/3V3) and interfacing requirements of GPS Receiver to PC are shown below.
Many embedded devices communicate over the serial port connection as most modern computers lack a hardware serial port;USB adaptors are used to convert USB data to standard serial port data and vice versa.
For a quick tutorial on USB to Serial Converter (5V/3V3) and connection details please Go through the link.
Once you are done with all these procedures , Choose the appropriate COM port that got assigned to the USB in your system by looking into the device manager like as shown below. In this figure you can see USB serial COM5 got selected.
Here sample test was done using GPRMC header . GPRMC tells the latitude, longitude, speed, time and date. The details of GPRMC message is shown below.

When GPS receiver get the weak signal,then the received GPS data is as shown in the figure. The alphabet ‘V’ on the GPRMC header indicate a weak signal from the satellite, which means by measuring distance from four satellites four spheres are drawn from earth to each satellite. Those spheres only intersect at only one earth point (your location). If there were only 3 satellites, there is more then one place the spheres intersect which is why the system needs that forth satellite so a bad calculation can not be made. The GPS receiver needs 4 satellites to work out your position in 3-dimensions. In GPS TTL Mini LED “blinks” in every fraction of seconds to indicate weak signal from satellites. When the GPS receiver gets stronger signal this LED is turned “on” The GPS receiver will send raw GPS data based on NMEA 0183 protocol to the PC.
When the GPS receiver gets stronger signal from satellite,the GPS data received is as shown in the figure.The alphabet ‘A’ on the GPRMC header indicate the strong signal from the satellite.

2. Test your GPS TTL Mini with rhydoLABZ Tracking Software

With the help of Hyper terminal or any other terminal software, you will only be able to see the full NMEA protocol coming in ASCII format and rhydoLABZ tracking software plot your location with the help of GOOGLE map.For using rhydoLABZ software you need to have net connectivity.Here one sample test is shown using RhydoLabz USB to Serial Converter (5V/3V3).

Install the rhydoLABZ Tracking Software (Windows) in your PC shown below.
Open rhydoLABZ Tracking software ,select appropriate COM port from “Select Comport “. The Latitude and Longitude details of the device will be shown in the rhydoLABZ Tracking software,you can get the map view of your location by simply clicking “plot”.

3. Test your GPS TTL Mini with Arduino

While interfacing GPS TTL Mini with Arduino, the data from GPS is available at TXD pin of the module which is connected to RXD pin of the Arduino board, connection diagram is shown below.
Testing with Arduino board, sample program is shown below

/**************************************************************************************
  Program to read GPS data and print data to serial monitor.
  BOARD   : Arduino Duemilanove
 **************************************************************************************/

  int Gpsdata;             // for incoming serial data
  unsigned int finish =0;  // indicate end of message
  unsigned int pos_cnt=0;  // position counter
  unsigned int lat_cnt=0;  // latitude data counter
  unsigned int log_cnt=0;  // longitude data counter
  unsigned int flg    =0;  // GPS flag
  unsigned int com_cnt=0;  // comma counter
  char lat[20];            // latitude array
  char lg[20];             // longitude array

   void Receive_GPS_Data();

/**************************************************************************************
  Function    : setup()
  Description : Use it to initialize variables, pin modes, start using libraries, etc.
                The setup function will only run once, after each power up or reset
                of the Arduino board.
**************************************************************************************/
  void setup()
  {
    Serial.begin(9600);   // opens serial port, sets data rate to 9600 bps
  }

/************************************************************************************
  Function    : loop()
  Description : loops consecutively, allowing your program to change and respond.
                Use it to actively control the Arduino board.
************************************************************************************/
  void loop()
  {
      Receive_GPS_Data();              
      Serial.print("Latitude  : ");
      Serial.println(lat);
      Serial.print("Longitude : ");
      Serial.println(lg);
      finish = 0;pos_cnt = 0;

  }
/************************************************************************************
  Function    : Receive_GPS_Data()
  Description : finding Latitudse and longitude from GPRMC message

************************************************************************************/
  void Receive_GPS_Data()
  {
    while(finish==0){
      while(Serial.available()>0){         // Check GPS data
        Gpsdata = Serial.read();
        flg = 1;
       if( Gpsdata=='$' && pos_cnt == 0)   // finding GPRMC header
         pos_cnt=1;
       if( Gpsdata=='G' && pos_cnt == 1)
         pos_cnt=2;
       if( Gpsdata=='P' && pos_cnt == 2)
         pos_cnt=3;
       if( Gpsdata=='R' && pos_cnt == 3)
         pos_cnt=4;
       if( Gpsdata=='M' && pos_cnt == 4)
         pos_cnt=5;
       if( Gpsdata=='C' && pos_cnt==5 )
         pos_cnt=6;
       if(pos_cnt==6 &&  Gpsdata ==','){   // count commas in message
         com_cnt++;
         flg=0;
       }

       if(com_cnt==3 && flg==1){
        lat[lat_cnt++] =  Gpsdata;         // latitude
        flg=0;
       }

       if(com_cnt==5 && flg==1){
         lg[log_cnt++] =  Gpsdata;         // Longitude
         flg=0;
       }

       if( Gpsdata == '*' && com_cnt >= 5){
         com_cnt = 0;                      // end of GPRMC message
         lat_cnt = 0;
         log_cnt = 0;
         flg     = 0;
         finish  = 1;

      }
    }
}
}

/**************************************************************************************

Program to read GPS data and print data to serial monitor.

BOARD : Arduino Duemilanove

**************************************************************************************/

int Gpsdata; // for incoming serial data

unsigned int finish =0; // indicate end of message

unsigned int pos_cnt=0; // position counter

unsigned int lat_cnt=0; // latitude data counter

unsigned int log_cnt=0; // longitude data counter

unsigned int flg =0; // GPS flag

unsigned int com_cnt=0; // comma counter

char lat[20]; // latitude array

char lg[20]; // longitude array

void Receive_GPS_Data();

/**************************************************************************************

Function : setup()

Description : Use it to initialize variables, pin modes, start using libraries, etc.

The setup function will only run once, after each power up or reset

of the Arduino board.

**************************************************************************************/

void setup()

{

Serial.begin(9600); // opens serial port, sets data rate to 9600 bps

}

/************************************************************************************

Function : loop()

Description : loops consecutively, allowing your program to change and respond.

Use it to actively control the Arduino board.

************************************************************************************/

void loop()

{

Receive_GPS_Data();

Serial.print("Latitude : ");

Serial.println(lat);

Serial.print("Longitude : ");

Serial.println(lg);

finish = 0;pos_cnt = 0;

}

/************************************************************************************

Function : Receive_GPS_Data()

Description : finding Latitudse and longitude from GPRMC message

************************************************************************************/

void Receive_GPS_Data()

{

while(finish==0){

while(Serial.available()>0){ // Check GPS data

Gpsdata = Serial.read();

flg = 1;

if( Gpsdata=='$' && pos_cnt == 0) // finding GPRMC header

pos_cnt=1;

if( Gpsdata=='G' && pos_cnt == 1)

pos_cnt=2;

if( Gpsdata=='P' && pos_cnt == 2)

pos_cnt=3;

if( Gpsdata=='R' && pos_cnt == 3)

pos_cnt=4;

if( Gpsdata=='M' && pos_cnt == 4)

pos_cnt=5;

if( Gpsdata=='C' && pos_cnt==5 )

pos_cnt=6;

if(pos_cnt==6 && Gpsdata ==','){ // count commas in message

com_cnt++;

flg=0;

}

if(com_cnt==3 && flg==1){

lat[lat_cnt++] = Gpsdata; // latitude

flg=0;

}

if(com_cnt==5 && flg==1){

lg[log_cnt++] = Gpsdata; // Longitude

flg=0;

}

if( Gpsdata == '*' && com_cnt >= 5){

com_cnt = 0; // end of GPRMC message

lat_cnt = 0;

log_cnt = 0;

flg = 0;

finish = 1;

}

When Arduino board receives GPS data,the data on serial monitor is shown below.

4. Test your Mini GPS with PIC16F877A

When interfacing GPS TTL Mini with PIC16F877A microcontroller, The TXD pin of the GPS TTL is connected to RXD pin of the microcontroller,connection diagram is shown below.

Testing Mini GPS TTL Mini with PIC16F877A, sample program is shown below.

/*******************************************************************************************
Microcontroller -- PIC 16 F877A - 40-pin-8-bit.                            
Clock Frequency is 20 MHz -- Period in 200 Nano second
baudrate-9600.Only the output message – $GPRMC (Recommended minimum specific
GNSS data) is read. The latitude and Longitude value is displayed in the Serial
monitor.      
*******************************************************************************************/

#include<pic.h>

/*******************************************************************************************
                               GLOBAL VARIABLES
*******************************************************************************************/

unsigned char Gpsdata;             // for incoming serial data
unsigned int finish =0;            // indicate end of message
unsigned int pos_cnt=0;            // position counter
unsigned int lat_cnt=0;            // latitude data counter
unsigned int log_cnt=0;            // longitude data counter
unsigned int flg    =0;            // GPS flag
unsigned int com_cnt=0;            // comma counter
unsigned char lat[20];             // latitude array
unsigned char lg[20];              // longitude array

/*******************************************************************************************  
                           FUNCTION DEFINITIONS
*******************************************************************************************/

void UART_Initilization();
void UART_String(const unsigned char *dat);

void main()
{
TRISC = 0X80;
UART_Initilization();             // uart Initialization
GIE  = 1;                         // Globel interrupt enable bit
PEIE = 1;                         // Peripheral interrupt enable bit
while(1){
  while(finish!=1);
   UART_String("Latitude  : ");    // printing GPS data to serial monitor
   UART_String(lat);
   UART_String("\r\n");
   UART_String("Longitude : ");
   UART_String(lg);
   UART_String("\r\n");
   finish = 0;
   pos_cnt = 0;
}
}

/*******************************************************************************************
Function    : interrupt ISR()
Description : interrupt service              
*******************************************************************************************/
void interrupt ISR()
{
    if(RCIF){
      RCIF = 0;
      Gpsdata = RCREG;
      flg = 1;
      if(finish == 0){
       if( Gpsdata=='$' && pos_cnt == 0)  // finding GPRMC header
         pos_cnt=1;
       if( Gpsdata=='G' && pos_cnt == 1)
         pos_cnt=2;
       if( Gpsdata=='P' && pos_cnt == 2)
         pos_cnt=3;
       if( Gpsdata=='R' && pos_cnt == 3)
         pos_cnt=4;
       if( Gpsdata=='M' && pos_cnt == 4)
         pos_cnt=5;
       if(Gpsdata=='C'  &&  pos_cnt == 5 )
         pos_cnt=6;
       if(pos_cnt==6    &&  Gpsdata ==','){  // count commas in message
         com_cnt++;
         flg=0;
       }

       if(com_cnt==3 && flg==1){
        lat[lat_cnt++] =  Gpsdata;        // latitude
        flg=0;
       }

       if(com_cnt==5 && flg==1){
         lg[log_cnt++] =  Gpsdata;        // longitude
         flg=0;
       }

       if( Gpsdata == '*' && com_cnt >= 5 && flg == 1){
         lat[lat_cnt] ='\0';             // end of GPRMC message
         lg[log_cnt]  = '\0';
         lat_cnt = 0;
         log_cnt = 0;
         flg     = 0;
         finish  = 1;
         com_cnt = 0;

      }
     }
    }
}

/*******************************************************************************************
Function    : USART_Initilization
Description : uart basic initilizatin                
*******************************************************************************************/
void UART_Initilization()
{
  TXEN   = 1;
  SYNC   = 0;
  BRGH   = 1;
  SPBRG  = 0X81;
  SPEN   = 1;
  CREN   = 1;
  RCIE   = 1;
  RCIF   = 0;
}

/*******************************************************************************************
Function    : USART_String
Description : transmiting string of datas
*******************************************************************************************/
void UART_String(const unsigned char *dat)
{
    while(*dat!='\0'){
    TXREG = *dat;
    while(TRMT!=1);
      dat++;
  }
}

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/*******************************************************************************************

Microcontroller -- PIC 16 F877A - 40-pin-8-bit.

Clock Frequency is 20 MHz -- Period in 200 Nano second

baudrate-9600.Only the output message – $GPRMC (Recommended minimum specific

GNSS data) is read. The latitude and Longitude value is displayed in the Serial

monitor.

*******************************************************************************************/

#include<pic.h>

/*******************************************************************************************

GLOBAL VARIABLES

*******************************************************************************************/

unsigned char Gpsdata; // for incoming serial data

unsigned int finish =0; // indicate end of message

unsigned int pos_cnt=0; // position counter

unsigned int lat_cnt=0; // latitude data counter

unsigned int log_cnt=0; // longitude data counter

unsigned int flg =0; // GPS flag

unsigned int com_cnt=0; // comma counter

unsigned char lat[20]; // latitude array

unsigned char lg[20]; // longitude array

/*******************************************************************************************

FUNCTION DEFINITIONS

*******************************************************************************************/

void UART_Initilization();

void UART_String(const unsigned char *dat);

void main()

{

TRISC = 0X80;

UART_Initilization(); // uart Initialization

GIE = 1; // Globel interrupt enable bit

PEIE = 1; // Peripheral interrupt enable bit

while(1){

while(finish!=1);

UART_String("Latitude : "); // printing GPS data to serial monitor

UART_String(lat);

UART_String("\r\n");

UART_String("Longitude : ");

UART_String(lg);

UART_String("\r\n");

finish = 0;

pos_cnt = 0;

}

/*******************************************************************************************

Function : interrupt ISR()

Description : interrupt service

*******************************************************************************************/

void interrupt ISR()

{

if(RCIF){

RCIF = 0;

Gpsdata = RCREG;

flg = 1;

if(finish == 0){

if( Gpsdata=='$' && pos_cnt == 0) // finding GPRMC header

pos_cnt=1;

if( Gpsdata=='G' && pos_cnt == 1)

pos_cnt=2;

if( Gpsdata=='P' && pos_cnt == 2)

pos_cnt=3;

if( Gpsdata=='R' && pos_cnt == 3)

pos_cnt=4;

if( Gpsdata=='M' && pos_cnt == 4)

pos_cnt=5;

if(Gpsdata=='C' && pos_cnt == 5 )

pos_cnt=6;

if(pos_cnt==6 && Gpsdata ==','){ // count commas in message

com_cnt++;

flg=0;

}

if(com_cnt==3 && flg==1){

lat[lat_cnt++] = Gpsdata; // latitude

flg=0;

}

if(com_cnt==5 && flg==1){

lg[log_cnt++] = Gpsdata; // longitude

flg=0;

}

if( Gpsdata == '*' && com_cnt >= 5 && flg == 1){

lat[lat_cnt] ='\0'; // end of GPRMC message

lg[log_cnt] = '\0';

lat_cnt = 0;

log_cnt = 0;

flg = 0;

finish = 1;

com_cnt = 0;

}

/*******************************************************************************************

Function : USART_Initilization

Description : uart basic initilizatin

*******************************************************************************************/

void UART_Initilization()

{

TXEN = 1;

SYNC = 0;

BRGH = 1;

SPBRG = 0X81;

SPEN = 1;

CREN = 1;

RCIE = 1;

RCIF = 0;

}

/*******************************************************************************************

Function : USART_String

Description : transmiting string of datas

*******************************************************************************************/

void UART_String(const unsigned char *dat)

{

while(*dat!='\0'){

TXREG = *dat;

while(TRMT!=1);

dat++;

}

When PIC16F877A microcontroller receive GPS data,the datas are displayed on serial monitor is as shown below.

Resources:
Mini GPS User Manual
Mini GPS Tool
rhydoLABZ Tracking Software (Windows)

How to Buy:
Click here to buy rhydoLABZ GPS TLL Mini.
Click here to buy RhydoLabz USB to Serial Converter (5V/3V3).

Support:
Please share your ideas with us, visit our forum for discussion

Frequently Asked Questions(FAQ):
Q.What is NMEA0183?
Ans.NMEA0183, or NMEA for short, stands for National Marine Electronics Association, a US standards committee that defines data message structure, contents and protocols to allow the GPS receiver to communicate with other pieces of electronic equipment. NMEA 0183 is a standard data communication protocol used by GPS receivers.

Q. Where do we mount GPS?
Ans. GPS data available around the world. The GPS receiver will need to have a clear View of sky so that the GPS receiver can triangulate at least three satellites. We may find problem receiving signals in indoor area. The GPS signal may blocked by metal, deep forest, mountains etc.

Q.Do we need net connection to work GPS TTL Mini with rhydoLABZ Software.
Ans. Yes we need net connection to work with rhydoLabz Software.

Q. Do we need net connection to work GPS?
Ans. No. we don’t need internet connection for GPS data reception.

Q . Does GPS TTL Mini need external antenna?
Ans. No, the module is made with inbuilt antenna.

16 Responses to "How To Obtain Latitude and Longitude from a GPS TTL Module"

vikash says:

October 18, 2013 at 11:16 am

In gps module two leds are used one is for power other is for 3D which always blinks… what is the 3D and what does it denote

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1. rhydo says:
  
  November 5, 2013 at 3:35 pm
  
  Hi,
  
  3D LED is used to denote, GPS Receiver is locked with enough Satellite to calculate your Co-ordinates.If it blinks, means the GPS modules cannot connect with the minimum satellite required.Please re arrange the position of the module so as to get the satellite.
  
  Better you place the GPS module under the open sky to confirm the the module functionality (3D Fix) and once everything is OK, you can move around.
  
  Log in to Reply
  1. AV says:
    
    May 11, 2017 at 4:44 pm
    
    3D LED is blinking continuously even under the open sky. Any other tips? What is the status of the light if the GPS is connected?
    
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    1. Hari Krishnan says:
      
      May 12, 2017 at 10:35 am
      
      3D LED Blinks when GPS is not fixed and it turns off when GPS is fixed. The GPS external antenna must be connected with the tracking shield while you working on it. It is strongly recommended to use a stand-alone 5V/2A power source, because the PC’s USB port might have not enough power to support the GSM and GPS.
      
      Log in to Reply
      1. AV says:
        
        May 14, 2017 at 4:53 pm
        
        Hi, I did not receive any external antenna with the gps unit. I bought it from Amazon.
      2. AV says:
        
        May 14, 2017 at 4:59 pm
        
        I have this http://www.rhydolabz.com/wireless-gps-c-130_186/gps-receiver-with-antenna-5v-ttl-serial-p-1313.html which claims to have an inbuilt antenna, can the module work with 5v/1A power source.
GPS Module Interfacing With Raspberry Pi says:

July 27, 2015 at 10:46 am

[…] To have a detailed analysis of the GPS module please visit http://www.rhydolabz.com/wiki/?p=658 […]

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GPS Module Interfacing With Raspberry Pi | Entesla Wiki says:

October 27, 2015 at 7:19 am

[…] check out more details on the GPS module, follow this link. If you are interested to know more about serial communication in RPi, there is […]

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Lavin Khandelwal says:

November 15, 2015 at 12:08 pm

I recently bought this module and while trying to work with it, i reversed the polarity of the VCC and the GND pin while connecting it to my arduino. Can anyone help me in testing if my module is still working fine?

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1. Harikrishnan says:
  
  November 27, 2015 at 10:26 am
  
  Simply power up the module and check the status of 3DFIX LED.
  Its its blinking, there is good chance that the module could be working.
  
  Log in to Reply
vikas says:

June 9, 2016 at 3:08 pm

can it work with 3.3 volt supply
given directly

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1. Hari Krishnan says:
  
  June 15, 2016 at 12:36 pm
  
  There are a couple of things that needs to be noted before answering this question.
  As per the datasheet, the current consumed by the GPS module while acquisition is 25mA & lets sum it up to a max of 40mA as a whole for the entire board.
  Now considering the TTL board, which contains an onboard regulator has a voltage dropout of 120mV @ 50mA current output.
  This means that the minimum input voltage that should be supplied to the board should be 3.42V to produce a 3.3V output from the regulator.
  Apart from all these, the GPS module can work with supply voltage as low as 3VDC. So, even if you provide a 3.3V at the VCC of the board, the module should be able to get enough supply voltage for it to function properly.
  
  Though it isn’t recommended, the board can work with 3.3V supply voltage.
  
  Log in to Reply
Souradeep says:

July 21, 2017 at 2:52 pm

How do I force the gps module to have a warm or hot start using arduino?

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1. Hari Krishnan says:
  
  July 27, 2017 at 11:30 am
  
  By using NMEA protocol we can achieve this warm and hot start. PMTK commands for this purposes are
  1) PMTK101 CMD HOT START
  Command purpose:
  Hot restart: Use all available data in the NV Store.
  Command number: 101
  DataField: None
  Example:
  $PMTK101*32
  
  2) PMTK102 CMD WARM START
  Command purpose:
  Warm restart: Don’t use ephemeris at re-start.
  Command number: 102
  DataField: None
  Example:
  $PMTK102*31
  
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Harish says:

January 25, 2018 at 3:29 pm

latitude and longitude is not displayed more than once… Why is it so??

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1. Hari Krishnan says:
  
  January 30, 2018 at 11:19 am
  
  The value of the latitude and longitude will change when the GPS location is changing. The data is continuously transmitted by the GPS satellites and the GPS receiver collects and stores the data.
  
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