UBLOX GPS module are normally delivered with a default configuration (generating automatically e.g some NMEA messages at 9600 bauds at a refresh rate of 1 hz).
oXs assumes that, at start up, GPS is working at 9600 bauds. oXs sent then some commands in order to
* - disable all NMEA messages
* - activates some UBX messages
* - increase frequency of calculation (to 10 or 5 Hz instead of 1hz)
* - set up the baud rate to 38400 instead of 9600.
Those parameters are not saved in the GPS (because some GPS modules does not allow it). So, oXs will send those commands at each power on.
If you oXs does not send GPS data, please check that your GPS module has still the default configuration (most important is that it is configured to receive UBX command messages at 9600 bauds).
An easy way to check the GPS configuration is to connect the GPS module to a 3.3 volt FTDI ( or USB to serial adapter) and to use a free software named "u-center".
This software is available on the official web site of UBLOX. More info is easily available on the web.