How to get continuous GPS data using the EM7430 modem?

IoT Modules MC/EM Series
1

Hello.

I’m trying to get GPS working on the EM7430 module on an OpenWRT system. The module is detected and enumerates three ports (ttyUS0, ttyUSB1, ttyUSB2). I use ttyUSB2 for AT commands.

I can get a static GPS location after a while, but I would like to get continuous NMEA sentences.
Currently, I can get a static location, but the tracking session ends with failcode 9 - even when I don’t end the session myself.

I use at!gpstrack=1,255,1000,30,1 to initiate the tracking session.

Here is the info for my module:

ati


Manufacturer: Sierra Wireless, Incorporated

Model: EM7430

Revision: SWI9X30C_02.14.03.00 r6134 CARMD-EV-FRMWR2 2016/03/28 14:34:14

MEID: 35907506268374

IMEI: 359075062683742

IMEI SV:  6

FSN: LR821125150210

+GCAP: +CGSM,+DS,+ES





OK

at!custom?


!CUSTOM: 

             GPSENABLE          0x01

             IPV6ENABLE         0x01

             UIM2ENABLE         0x01

             SIMLPM             0x01

             USBSERIALENABLE    0x01

             SINGLEAPNSWITCH    0x01





OK

at!gpsstatus?
at!gpsstatus?


Current time: 2019 08 19 0 14:03:26



1980 01 06 6 00:00:00 Last Fix Status    = FAIL,  FAILCODE = 0

2019 08 19 0 14:02:14 Fix Session Status = ACTIVE



at!gpssatinfo?
at!gpssatinfo?


Satellites in view:  12 (2019 08 19 0 14:05:32)

* SV:  3  ELEV:  7  AZI:  258  SNR: 19

* SV:  8  ELEV: 23  AZI:  324  SNR: 22

* SV: 16  ELEV: 35  AZI:  217  SNR: 22

* SV: 22  ELEV: 15  AZI:  278  SNR: 22

* SV: 23  ELEV:  3  AZI:  216  SNR: 31

* SV: 26  ELEV: 28  AZI:  184  SNR: 19

* SV: 27  ELEV: 65  AZI:  326  SNR: 22

* SV: 31  ELEV: 32  AZI:  142  SNR: 31

* SV: 82  ELEV: 15  AZI:  136  SNR: 33

* SV: 73  ELEV:  9  AZI:  208  SNR: 33

* SV: 80  ELEV: 11  AZI:  151  SNR: 29

* SV: 71  ELEV: 21  AZI:  230  SNR: 24



OK

at!gpsloc?
at!gpsloc?


Lat: XX Deg XX Min XX Sec S  (0x00000000)

Lon: XX Deg XX Min XX Sec E  (0x00000000)

Time: 2019 08 19 0 14:05:45 (GPS) 

LocUncAngle: 0.0 deg  LocUncA: 467 m  LocUncP: 39 m  HEPE: 468.625 m

2D Fix 

Altitude: -60 m  LocUncVe: 384.0 m



OK

at!gpsstatus?
at!gpsstatus?


Current time: 2019 08 19 0 14:06:01



2019 08 19 0 14:05:26 Last Fix Status    = FAIL,  FAILCODE = 9

2019 08 19 0 14:05:26 Fix Session Status = FAIL,  FAILCODE = 9



TTFF (sec) = 426



OK

After getting a fix the GPS status changes to failcode 9 (user ended the session).

I’ve also tried writing $GPS_START into /dev/ttyUSB1, but I still cannot get any data from it.

Thanks.

2

I can see there is continuous GPS data coming out to the NMEA port.
at!gpstrack=1,255,1000,30,1
OK
ati3
Manufacturer: Sierra Wireless, Incorporated
Model: MC7430
Revision: SWI9X30C_02.30.03.00 r7804 CARMD-EV-FRMWR2 2018/07/25 01:10:04
MEID: 35907406009754
IMEI: 359074060097542
IMEI SV: 17
FSN: LU626300170410
+GCAP: +CGSM

OK
at!gpsnmeaconfig?
Enabled: 1
Output Rate: 1

OK

3

I had to send the GPS_START command in the following format.

echo \$GPS_START > /dev/ttyUSB

The back-slash did the trick.