Hi plu
In this case I was just testing so I used the USB serial port which streams NMEA into my host computer. I then observed the satalite data with the SW GPS tool which does a reasonable job of displaying the data
On the target device I controlled the GPS with the Legato command line tool “gnss” - of course this tool uses the Legato API to talk to the Qualcomm device.
I think that on the Target device linux command line the command
gnss fix
gives a reasonable indication of the TTFF