With the Pinnacle 100 Cellular Modem, why can the GPS location not be retrieved while being connected to a LTE network?

Answer

In the Pinnacle 100 the GPS radio hardware is shared with the LTE radio hardware.
This means LTE needs to temporarily be disabled so that the GPS engine can take over the RF circuit to generate GPS location output.
To disable LTE, Airplane Mode needs to be enabled using the AT command at+cfun=4,0
To disable Airplane Mode again issue at+cfun=1,0.