# MC7455 GPS no Fix

**URL:** <https://forum.sierrawireless.com/t/mc7455-gps-no-fix/16268>\
**Category:** MC/EM Series\
**Created:** [May 1, 2019, 1:12pm UTC](https://forum.sierrawireless.com/t/mc7455-gps-no-fix/16268 "2019-05-01T13:12:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rhao](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@rhao](https://forum.sierrawireless.com/u/rhao)\
**Post date:** [May 1, 2019, 1:12pm UTC](https://forum.sierrawireless.com/t/mc7455-gps-no-fix/16268/1 "2019-05-01T13:12:01Z")

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Hello,

I am trying to use the GPS of a MC7455, with no success…  
I work on ubuntu linux with:  
Manufacturer: Sierra Wireless, Incorporated  
Model: MC7455  
Revision: SWI9X30C\_02.24.05.06 r7040 CARMD-EV-FRMWR2 2017/05/19 06:23:09  
MEID: 35907206321118  
IMEI: 359072063211185  
IMEI SV: 12  
FSN: LQ842642370110  
+GCAP: +CGSM

The GSM works correctly.

I can get NMEA messages on the ttyUSB1 but they never contains any time or position data, no fix is ever made.  
Sometimes the NMEA shows that up to 13 satellites are found. I then waited for hours but it never gets data.  
I test with two different types of antennas on different PC, and I tried two different MC7455 with no success.

So far I did:

- disabling NetworkManger and ModemManager --\> no changes

- at!gpsstatus? -\> it always respond the following answers (the second one after a while):

- at!gpstrack? -\> it always respond ERROR as if the command is not recognized

- I played with the setting of at!custom: changed the combinations of values with no effects:  
at!custom=“GPSSEL”,0 or 1  
at!custom=“GPSLPM”,0 or 1

- at!GPSAUTOSTART=1,1,255,100,1 --\> no effects  
at!GPSAUTOSTART?  
function: 1  
fixtype: 1  
maxtime: 255 seconds  
maxdist: 100 meters  
fixrate: 1 seconds  
OK

- at!gpsloc? --\>  
Not Available

- at!GPSSATINFO? --\>  
NO SAT INFO

At the moment I am completely stuck any ideas what I could try?

Thanks,  
raphael

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**Author:** ![Oedenburger](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/oedenburger/32/4028_2.png) [@Oedenburger](https://forum.sierrawireless.com/u/Oedenburger)\
**Post date:** [May 1, 2019, 3:44pm UTC](https://forum.sierrawireless.com/t/mc7455-gps-no-fix/16268/2 "2019-05-01T15:44:53Z")

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Hi Raphael,

If you have access to a SWI MC devkit, try with that.  
Are you indoors?  
Do you get a fix when you are outside?

Thanks,  
James

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**Author:** ![rhao](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@rhao](https://forum.sierrawireless.com/u/rhao)\
**Post date:** [May 1, 2019, 4:10pm UTC](https://forum.sierrawireless.com/t/mc7455-gps-no-fix/16268/3 "2019-05-01T16:10:19Z")

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Thanks for your answer James!

I found out what was wrong, i was convinced to be using passive antennas, but they are active.  
When I switched : at+want to 1 it worked

at+want=1

Cheers,  
raphael