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.


  • 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
  • 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)


PIN Diagram:

GPS  TTL Mini  PIN descriptions are as below


  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

  •  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. 

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


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).

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.

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