GNSS software development

16 Jan 2014

Specific information regarding the recommended method for accessing data from the built-in GPS (without just using direct access to the hardware port, thus breaking the GPS gadgets on the home screen) is provided at the following web links.

Official sample code from Microsoft is provided at the following web page and sub-links.

Otherwise, you can view default GPS COM port assignments at this web page (recommended to use the virtual GPS COM2 Program port when possible, again to avoid interference with built-in GPS utilities).

Default COM Port Number Assignments

GPS Serial port pass-through

OS release 1.6.3 and higher on the Allegro 2 and Archer 2 provides a "GNSS Stream" utility to allow GPS data from the built-in receiver to be output through another port such as COM1 for use by an external device. A similar, though more in-depth third-party utility for enabling serial pass-through of GPS data is described and available at this web page.

Additional info for Allegro 2 and Archer 2

Newer Allegro 2 units now come standard with the U-Blox NEO M8T receiver installed which can potentially output UBX data for further differential correction. Newer Archer 2 units come with the U-Blox NEO M8N receiver, or an optional M8T. An optional external antenna port is also available on new M8T unit purchases. This is similar to the Mesa 2. To detect if a unit has a U-Blox or NVS receiver, you can call our JSGetDeviceInfo function as described in the documentation starting at this web page.

Custom APIs (Application Programming Interfaces)

Or you can look under the following registry key.



Where “string”, for NVS is, “NVS NV08C”, and for U-Blox will be a value that the U-Blox module reports.

On previous Allegro 2 and Archer 2 units with the integrated NVS 08C-MCM receiver, in order to enable COM4 to the second module port (default BINR protocol), you will need to change these registry settings then soft Reset.


"Function"=dword:1 ; 0 - not in use, 1 = COM4_RXD (pins 2 through 5 must be function 0)


"Function"=dword:1 ; 0 - not in use, 1 = COM4_TXD (pins 2 through 5 must be function 0)

This port defaults to 115200 baud, similar to the COM8 GPS (default NMEA protocol) port. Both ports can be used simultaneously. The protocol of either port can be changed by sending the correct command to the receiver.

Some example source code for accessing the BINR data through COM4 is provide in the following file.

Additional information is provided at this web page.