GNSS not displaying altitude and losing satelites

I have some major issues regarding GNSS integrated inside HL6528G-2.8V module. I will try to specify as precisely as posible what is happening.

  1. When device is operating on a viechle that passes from one base station to another and somethimes losses signal and connection to the network. After it connects again to the network and regain TCP/IP connection to the server sometimes „AT+GPSPVT=4,0,3/r/n“ command doesn’t return any “+GPSPVT” answers and only thing that I can do is issue „AT+GPSSTART=0/r/n“ command to restart it.
    Problem is that than it losses all satelites and coordinates and I have to wait to regain them like it had hard reset.(complete start from power off state)
    This happends to often: 1 of 10 times when reconnecting to network

  2. Next thing is that when viechle moves (tested scenario is 80km/h), and „AT+GPSSTART=0/r/n“ comand is issued sometimes it takes up to 10min to TTFF (get coordinates), this happends very rare but we never can wait that long.

  3. Further issue is about height information that doesn’t exists (it never shows it)… this is on all modules and firmwares I tested, you can try it also.
    weather is NMEA or GPSPVT mesages.

Example(bold is height):
+GPSPVT: 0,23:01:11,28/10/2014,3D FIX,N 45 09’07.25",E 014 32’18.66",+0000m
+GPSPVT: 1,066.7deg,000m/s

I have latest vesion of firmware:
23:04:08.401> ATI3
23:04:08.430> SIERRA HL6N,002.00.200F.7152A
23:04:08.430> OK

There are some more issues with reconections when signal is lost and regained but that I can handle. IMPORTANT IS THAT GNSS ALWAYS HAVE COORDINATES AND NEVER RESETS!!!

Are this issues happening only to me or is it HL6528G firmware issue?

Best Regards,