I thought you could be missing "fake_gps":false and "gps":true, but it seems it is trying to use the gps anyway. I’d say check directly with cat to see you get a fix, which should give you something like this (notice how it’s normal to have a lot of “faulty” lines):
$GPRMC,123004.00,A,3326.00650,S,07037.16455,W,0.407,,030419,,,A*70
$GPGSA,A,3,26,29,20,10,21,,,,,,,,4.41,2.56,3.59*02
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPTXT,01,01,01,NMEA unknown msg*58
$GPRMC,123006.00,A,3326.00677,S,07037.16380,W,0.410,,030419,,,A*7E
$GPVTG,,T,,M,0.410,N,0.759,K,A*2D
$GPGSA,A,3,26,29,20,10,21,,,,,,,,4.41,2.56,3.59*02
If you do get that, eventually you should see something like this at your packet forwarder:
Apr 03 09:29:48 MNGW0000 ttn-gateway[317]: ### [GPS] ###
Apr 03 09:29:48 MNGW0000 ttn-gateway[317]: # Valid gps time reference (age: 0 sec)
Apr 03 09:29:48 MNGW0000 ttn-gateway[317]: # System GPS coordinates: latitude -33.43346, longitude -70.61944, altitude 587 m
If you get the fix and still the packet forwarder doesn’t work, then I’d say there may be an specific issue with the beacon packet forwarder regarding gps (I have never used it, sorry). If, instead, you never get a gps fix, then you’ll have to double check it.
Sorry if that doesn’t seem very helpful, I’m no gps nor packet forwarder expert.