I'm using CSR109-8G-2HnD-IN Cloud Router Switch.
The Router OS is upgraded to version 6.20
GPS Package installed (ver. 6.20)

Using WinBox or Router configuration webpage:
In the left menu: System the GPS menù item is not displayed.

The GPS driver seem to be configurable using 'Terminal' utility.

Can anyone give me help ?

Thanks in advance for support.

That's correct.
The GPS functions can be configured via the command line.

Look here for help:
http://wiki.mikrotik.com/wiki/Manual:System/GPS

Make sure to follow the instructions to configure the port first as outlined in the above!