GNSS-Service em 7421 only 2D


I`m using an embedded Modem,Typ em7421. The modem works but when I use the GNSS-Services, i only get 2D-fixes. When i start the service sometimes there are two or three 3D-fixes.
I use the latest driver from sierra wireless.
Can anyone help?

Are you in outdoor area?

when i test it, im outside for a longer period.
As i wrote, I get GPS-Information but only 2D

If it happens sometimes, maybe related to the satellite signal
BTW, did you check AT!gpssatinfo?