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Grove - GPS

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 channels 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.


We've released the Seeed GPS Modules Selection Guide, it will help you choose the GPS Module that best suits your needs.


Product VersionChangesReleased Date
Grove - GPS V1.2InitialOct 2015


  • 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

ArduinoRaspberry Pi
The platforms mentioned above as supported is/are an indication of the module's software 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

If this is the first time you work with Arduino, we firmly recommend you to see [Getting Started with Arduino]( before the start.

Play With Arduino

This sample simply reads from the GPS by using software serial and sends it back on the serial port.


  • Step 1. Prepare the below stuffs:
Seeeduino V4.2Base ShieldGrove - GPS
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  • Step 2. Connect Grove - GPS to port D2 of Grove-Base Shield.
  • Step 3. Plug Grove - Base Shield into Seeeduino.
  • Step 4. Connect Seeeduino to PC via a USB cable.


If we don't have Grove Base Shield, We also can directly connect Grove - GPS to Seeeduino as below.

SeeeduinoGrove - GPS


Please note that the u-center software is for windows only.
  • Step 1. Install u-center software.
  • Step 2. Copy the code into Arduino IDE and upload. If you do not know how to upload the code, please check how to upload code.
#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
  • Step 3. Open U-center.

  • Step 4. Click Receiver -> Port and select the COM port that the Arduino is using.

  • Step 5. Click Receiver -> Baudrate and make sure 9600 is selected.

  • Step 6. Click View -> Text Console and you should get a window that will stream NMEA data.

  • Step 7. Open the serial monitor,You can see as show below:

We also can view data in Google Earth:

  • Step 1. Click File -> Database Export -> Google Earth KML

  • Step 2. This should launch Google Earth with the history that was captured by u-center.

  • Step 3. Alternatively, data can be recorded by pressing the red circle on the toolbar which will then ask where you want to save the record.

  • Step 4. When we have captured enough data, click the black square to stop recording.

  • Step 5. We can then convert the .ubx file generated to KML by using uploading the ubx file to GPSVisualizer.

Play With Raspberry Pi


  • Step 1. Prepare the below stuffs:
Raspberry piGrovePi_PlusGrove - GPS
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  • Step 2. Plug the GrovePi_Plus into Raspberry.
  • Step 3. Plug the sensor to grovepi+ socket RPISER by using a grove cable.
  • Step 4. Connect the Raspberry to PC through USB cable.


  • Step 1. Follow Setting Software to configure the development environment.

  • Step 2. Navigate to the demos' directory:

cd ~
git clone
cd GrovePi/Software/Python/grove_gps
  • Step 3. 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
#import ir_receiver_check


#if ir_receiver_check.check_ir():
# print("Disable IR receiver before continuing")
# exit()

ser = serial.Serial('/dev/ttyAMA0', 9600, timeout = 0) #Open the serial port at 9600 baud

def cleanstr(in_str):
out_str = "".join([c for c in in_str if c in "0123456789.-" ])
if len(out_str)==0:
out_str = "-1"
return out_str

def safefloat(in_str):
out_str = float(in_str)
except ValueError:
out_str = -1.0
return out_str

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] =='$GPGGA': # GGA data , packet 1, has all the data we need
time.sleep(0.1) #without the cmd program will crash
ind=GPS.inp.index('$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):
if enable_debug:


if GPS.GGA[2]=='': # latitude. Technically a float
lat =-1.0

if GPS.GGA[3]=='': # this should be either N or S

if GPS.GGA[4]=='': # longitude. Technically a float

if GPS.GGA[5]=='': # this should be either W or E


if GPS.GGA[9]=='':
# change to str instead of float
# 27"1 seems to be a valid value
return [time,fix,sats,alt,lat,lat_ns,long,long_ew]

# Convert to decimal degrees
def decimal_degrees(self, raw_degrees):
degrees = float(raw_degrees) // 100
d = float(raw_degrees) % 100 / 60
return degrees + d
return raw_degrees

if __name__ == "__main__":
if enable_save_to_file:
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,longitude,long_ew]=g.vals() #Get the individial values

# Convert to decimal degrees
if lat !=-1.0:
lat = g.decimal_degrees(safefloat(lat))
if lat_ns == "S":
lat = -lat

if longitude !=-1.0:
longitude = g.decimal_degrees(safefloat(longitude))
if long_ew == "W":
longitude = -longitude

# print ("Time:",t,"Fix status:",fix,"Sats in view:",sats,"Altitude",alt,"Lat:",lat,lat_ns,"Long:",long,long_ew)
print("Time\t\t: %s\nFix status\t: %d\nSats in view\t: %d\nAltitude\t: %s\nLat\t\t: %f\nLong\t\t: %f") %(t,fix,sats,alt,lat,longitude)
print("Time\t\t: %s\nFix status\t: %s\nSats in view\t: %s\nAltitude\t: %s\nLat\t\t: %s\nLong\t\t: %s") %(t,str(fix),str(sats),str(alt),str(lat),str(longitude))


if enable_save_to_file:
f.write(s) #Save to file
except IndexError:
print ("Unable to read")
except KeyboardInterrupt:
if enable_save_to_file:
print ("Exiting")
  • Step 4. 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

  • Step 1. Grove-GPS has change the module as SIM28 which the same footprint as origin version.
  • Step 2. We should use "SIMCom GPS DEMO" tools to receive SIM28 module data.
  • Step 3. Open SIMCom_GPS_DEMO tools, go to Module->properties->module->select SIM28.
  • Step 4. SIMCom_GPS_DEMO_V1.07 is for Windows only.

  • Step 5. Open SIMCom_GPS_DEMO tools, go to Module->connect. Select the serial port which the GPS module used.

Schematic Online Viewer



Project of GPS/GPRS Tracker: In this new project we will present our GPS Tracker connected using the GPRS technique and MQTT protocol.

Tech Support & Product Discussion

Thank you for choosing our products! We are here to provide you with different support to ensure that your experience with our products is as smooth as possible. We offer several communication channels to cater to different preferences and needs.

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