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This Wiki page contains additional information for the Modtronix GPS-VK2828U7G5 GPS Module. Please feel free to register and improve this page - user contributions are greatly appreciated!

GPS VK2828U7G5 (or VK2828U7G5LF) Module with integrated antenna, and including cable. This module looks identical to the VK16U6, but uses the newer ublox G7020-KT chip. It should also be hardware and software compatible.


  • Based on u-Blox G7020-KT Chip (Part of u-blox 7 GNSS Chip Family)
  • Standard 25*25*4MM high sensitivity GPS antenna
  • UART/TTL,232 optional interface
  • Supply Voltage 3.3V
  • Adopt KDS 0.5 PPM High Precision TCXO
  • Built-in Backup Battery
  • Built-in SQI Flash
  • Built-in RTC crystal
  • Built-in LNA, Low-noise amplifier
  • 1-10Hz
  • Support AssistNow Online and AssistNow Offline


Wiring Diagram

Pin Description

This GPS receiver has 6 pins for connections:

  • VCC - Supply voltage positive pin, must be connected to an external 3.3V supply.
  • GND - Supply voltage ground pin.
  • RX - UART receive (TTL) pin. Note that this pin has UART TTL signals, and can NOT be connected to a com port of a PC. Should be connected directly to the UART Transmit pin of a microcontroller.
  • TX - UART transmit (TTL) pin. Note that this pin has UART TTL signals, and can NOT be connected to a com port of a PC. Should be connected directly to the UART Receive pin of a microcontroller.
  • VCC_N - This is for enabling the uBlox module. This pin should be connected to GND or left floating for the module to be ON. If this pin is connected to the VCC, then the module will be turned OFF. This is useful to save power, i.e. once you have obtained a fix, you can turn OFF the power to the GPS module.
  • PPS - This is for determine whether the uBlox module has obtained a GPS fix. Based on the location of the GPS receiver, it will take some time (30 sec to 1 min) to obtain a fix. This pin can be used as an interrupt line to indicate when a fix is available.

Communication Protocol

This module supports the standard GPS NMEA protocol. For full details, see “23 NMEA Messages Overview” chapter of receiver datasheet and protocol document. An overview of the NMEA protocol is also available here.

GPS Testing

The default baud rate of this module is 9600 baud.

Once connected, various data will will be sent out via the UART transmit pin untill the GPS receiver acquires a lock. Once the device has obtained a successful lock, the following text will be output.


Let us take the line starting with “$GPGLL” and understand what it means.

The GPGLL information provides the “Geographic Position, Latitude / Longitude and time”. Notice that there are 7 entries separated by commas. Consider the GPGLL in the above line, here is a description of what they mean.

Field Position Value Description
1 1255.23533 This field specifies the current latitude
2 N This field specifies North or South direction
3 07735.22950 This field specifies the current longitude
4 E This field specifies East or West direction
5 093010.00 This field specifies the UTC time of the position in format
6 A This field indicates the status of the data. 'A' indicates the data is valid
7 A*6F This field indicates the check sum

For more information on the NMEA strings outputed by the GPS module, see this page.

Arduino Code

There seems to be a lot of online resources available for using Arduino with ublox GPS chips. Just google is.
This project is based specifically on this VK2828U7G5 module.

products/modules/gps-vk2828u7g5.txt · Last modified: 2015/09/10 21:53 by modtronix