Grove - GPS


3.3V 5.0V UART
This Grove - GPS module is a cost-efficient and field-programmable gadget armed with a SIM28 (u-blox 6 is the old version) and serial communication configuration. It features 22 tracking / 66 acquisition channel GPS receiver. The sensitivity of tracking and acquisition both reach up to -160dBm, making it a great choice for personal navigation projects and location services, as well as an outstanding one among products of the same price class.


  • Supports NMEA and u-blox 6 protocols. ( Till Jan,10 2014, after that SIM28 instead)
  • Low power consumption
  • Baud rates configurable
  • Grove compatible interface
More details about Grove modules please refer to Grove System


Input Voltage3.3/5V
BaudRate4800 - 57600(u-blox version)
BaudRate9600 - 115200(SIM28 version)
Default BaudRate9600

Platforms Supported

ArduinoWioBeagleBoneRaspberry PiLinkIt ONE
The platforms mentioned above as supported is/are an indication of the module's hardware or theoritical compatibility. We only provide software library or code examples for Arduino platform in most cases. It is not possible to provide software library / demo code for all possible MCU platforms. Hence, users have to write their own software library.

Getting Started

Following documents help in getting the user started with Grove.


With Arduino

This sample simply reads from the GPS using software serial and sends it back out on the serial port.
  1. Connect the Grove-GPS to Digital I/O 2 on the Grove - Base Shield using a Grove Universal 4 pin cable.
  2. Upload the code below.
// link between the computer and the SoftSerial Shield
//at 9600 bps 8-N-1
//Computer is connected to Hardware UART
//SoftSerial Shield is connected to the Software UART:D2&D3
#include <SoftwareSerial.h>
SoftwareSerial SoftSerial(2, 3);
unsigned char buffer[64];                   // buffer array for data receive over serial port
int count=0;                                // counter for buffer array
void setup()
    SoftSerial.begin(9600);                 // the SoftSerial baud rate
    Serial.begin(9600);                     // the Serial port of Arduino baud rate.
void loop()
    if (SoftSerial.available())                     // if date is coming from software serial port ==> data is coming from SoftSerial shield
        while(SoftSerial.available())               // reading data into char array
            buffer[count++];      // writing data into array
            if(count == 64)break;
        Serial.write(buffer,count);                 // if no data transmission ends, write buffer to hardware serial port
        clearBufferArray();                         // call clearBufferArray function to clear the stored data from the array
        count = 0;                                  // set counter of while loop to zero
    if (Serial.available())                 // if data is available on hardware serial port ==> data is coming from PC or notebook
    SoftSerial.write(;        // write it to the SoftSerial shield
void clearBufferArray()                     // function to clear buffer array
    for (int i=0; i<count;i++)
    }                      // clear all index of array with command NULL
  • Install u-center. Upload the code below to your Arduino/Seeeduino and then open u-center.
Please note that the u-center sofeware is windows only.
  1. Click Receiver -> Port and select the COM port that the Arduino is using.
  2. Click Receiver -> Baudrate and make sure 9600 is selected.
  3. Click View -> Text Console and you should get a window that will stream NMEA data.
  4. Open the serial monitor,You can see as show below:
  • To View data in Google Earth:
    1. Click File -> Database Export -> Google Earth KML
    2. This should launch Google Earth with the history that was captured by u-center.
    3. Alternatively, data can be recorded by pressing the red circle on the toolbar which will then ask you where you want to save the record.
    4. When you have captured enough data, click the black square to stop recording.
    5. You can then convert the .ubx file generated to KML by using uploading the ubx file to GPSVisualizer.

With Raspberry Pi

1.You need a Raspberry Pi and a GrovePi or GrovePi+.
2.You should have completed configuring the development environment, otherwise follow here.
  • Plug Grove GPS into grovepi socket RPISER.
4.Navigate to the demos’ directory:
    cd yourpath/GrovePi/Software/Python/
  • To see the code
    nano   # "Ctrl+x" to exit #
import serial, time
import smbus
import math
import RPi.GPIO as GPIO
import struct
import sys
ser = serial.Serial('/dev/ttyAMA0',  9600, timeout = 0)   #Open the serial port at 9600 baud
class GPS:
    #The GPS module used is a Grove GPS module
    # Refer to SIM28 NMEA spec file
    #Read data from the GPS
    def read(self):
        while True:
            if GPS.inp[:6] =='$GPGGA': # GGA data , packet 1, has all the data we need
            ind=GPS.inp.index('$GPGGA',5,len(GPS.inp)) #Sometimes multiple GPS data packets come into the stream. Take the data only after the last '$GPGGA' is seen
        except ValueError:
            print ""
        GPS.GGA=GPS.inp.split(",")   #Split the stream into individual parts
        return [GPS.GGA]
    #Split the data into individual elements
    def vals(self):
        return [time,fix,sats,alt,lat,lat_ns,long,long_ew]
f=open("gps_data.csv",'w')   #Open file to log the data
f.write("name,latitude,longitude\n")   #Write the header to the top of the file
while True:
    try:  #Read from GPS
        [t,fix,sats,alt,lat,lat_ns,long,long_ew]=g.vals() #Get the individial values
        print "Time:",t,"Fix status:",fix,"Sats in view:",sats,"Altitude",alt,"Lat:",lat,lat_ns,"Long:",long,long_ew
        f.write(s)   #Save to file
    except IndexError:
        print "Unable to read"
    except KeyboardInterrupt:
        print "Exiting"
5.Run the demo.
    sudo python
GPS is better used outdoors. It is recommended to put your raspberry pi outside the window or any place outdoors.

SIM28 module Note:

  1. GPS Bee has change the module as SIM28 which the same footprint as origin version.
  2. You should use “SIMCom GPS DEMO” tools to receive SIM28 module data.
  3. Open SIMCom_GPS_DEMO tools, go to Module->properties->module->select SIM28.
  4. SIMCom_GPS_DEMO_V1.07 is Windows only.
  5. Open SIMCom_GPS_DEMO tools, go to Module->connect. Select the serial port which the GPS module used.


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