Hi,
I am running an EM7455 on an embedded linux system and I am able to connect to the GPS using /dev/ttyUSB1. I echo $GPS_START to the port and I see NMEA messages, but after 3 minutes the messages stop, even while the GPS continues to run and attach to satellites and update the location?
For the NMEA port:
$ echo $GPS_START > /dev/ttyUSB1
$ cat < /dev/ttyUSB1
$GPVTG,T,M,N,K,N*2C
$GPGSA,A,1,*1E
$GPGGA,0,*66
$GPRMC,V,N*53
After 3 minutes the output stops.
on /dev/ttyUSB2:
AT+WANT=1 //Enable the GPS active antenna
AT!GPSSTATUS?
Current time: 1980 01 06 6 00:02:58
1980 01 06 6 00:02:58 Last Fix Status = NONE
1980 01 06 6 00:00:18 Fix Session Status = ACTIVE
No TTFF available
OK
AT!GPSSATINFO?
Satellites in view: 13 (1980 01 06 6 00:05:54)
SV: 1 ELEV: 9 AZI: 317 SNR: 18
SV: 8 ELEV: 27 AZI: 264 SNR: 29
SV: 10 ELEV: 50 AZI: 54 SNR: 21
SV: 11 ELEV: 20 AZI: 310 SNR: 26
SV: 14 ELEV: 73 AZI: 246 SNR: 23
SV: 18 ELEV: 28 AZI: 81 SNR: 33
SV: 21 ELEV: 11 AZI: 142 SNR: 19
SV: 22 ELEV: 6 AZI: 286 SNR: 23
SV: 24 ELEV: 7 AZI: 37 SNR: 22
SV: 27 ELEV: 24 AZI: 223 SNR: 19
SV: 31 ELEV: 21 AZI: 170 SNR: 29
SV: 32 ELEV: 79 AZI: 352 SNR: 23
SV: 48 ELEV: 0 AZI: 0 SNR: 35
OK
AT!GPSSTATUS?
Current time: 1980 01 06 6 00:06:09
1980 01 06 6 00:06:09 Last Fix Status = SUCCESS
1980 01 06 6 00:06:09 Fix Session Status = ACTIVE
I would suggest the first thing to do is upgrade the firmware, 2.08 is 2 years old now and there have been a lot of changes/improvements in the firmware.
2017 11 01 2 16:14:37 Last Fix Status = SUCCESS
2017 11 01 2 16:14:37 Fix Session Status = ACTIVE
TTFF (sec) = 102
OK
(But nmea port stops after 3 minutes of messages)
Hi Karppa, I am indoors so the signal strength is relatively low, but I see the same behavior when I am near a window and the signals are stronger
While the messages are streaming I can start and stop with $GPS_START and $GPS_STOP, but after 3 minutes I don’t see output even when I try to restart the interface with the commands.
The weird thing is that the location is being still being updated through the AT query, so I don’t think the fix is timing out
at!gpsloc?
Lat: XX Deg XX Min 7.73 Sec N (0xXXXXXXXX)
Lon: XXX Deg XX Min 31.22 Sec W (0xXXXXXXXX)
Time: 2017 11 01 2 17:44:11 (GPS)
LocUncAngle: 0.0 deg LocUncA: 7 m LocUncP: 6 m HEPE: 9.219 m
3D Fix
Altitude: 114 m LocUncVe: 8.0 m
Heading: 0.0 deg VelHoriz: 0.0 m/s VelVert: 0.0 m/s