Satellite fix problem in CC4000 module

We are interfacing CC4000 GPS Module with EKS-LM3S6965.

We connected the GPS module with the microcontroller by reffering the datasheet and User Manual.

We found that the boot up sequence got finished and the GPS engine is in acquisition mode as the led was initially double blinking and then blinking.

But the led is not continuously on from which we inferred that the position is not fixed (satellite not getting locked on).

So can you suggest a way so that we could overcome this problem.

The output which we are getting now looks like this:

$PTIGCD,1,1,CFWVER,P,CC4000,R,00.98.00,Jul 28 2011,19:45:59*07
$PTIGCD,1,1,GPSVER,C,02.00,5f,R,01.09.01.00,12/26/2008,P,31.75,08/01/2011*57
$GPGLL,,,,,,V,N*64
$GPRMC,,V,,,,,,,,,,N*53
$GPGGA,,,,,,0,,,,,,,,*66
$GPVTG,,T,,M,,N,,K,N*2C
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,1,1,00*79

  • Hello Ramesh,

    What sort of antenna are you using? And where are you doing the testing?

    Thanks,

    Aaron

  • In reply to Aaron Lee5:

    We are using on board chip antenna.

    We are doing the testing in open space during which we got the following ouput.

    $GPGLL,,,,,,V,N*64
    $GPRMC,,V,,,,,,,,,,N*53
    $GPGGA,,,,,,0,,,,,,,,*66
    $GPVTG,,T,,M,,N,,K,N*2C
    $GPGSA,A,1,,,,,,,,,,,,,,,*1E
    $GPGSV,3,1,12,13,08,234,,14,09,065,,17,20,282,,01,31,192,*7D
    $GPGSV,3,2,12,31,50,101,,20,73,222,,04,19,318,,32,64,137,*78
    $GPGSV,3,3,12,25,20,040,,12,14,004,,23,38,229,,11,08,191,*7B

  • In reply to Ramesh Manoharan:

    Ramesh,

    Sorry for the delay. According to the data shown, there are no SVs being tracked. These sorts of results are given when those SVs are detected, and then lost. All indications are that the software is functioning normally, and that the CC4000 is being communicated with correctly. This means that the problem is most likely the quality of the signal getting to the chip. This can come from either environmental or hardware issues

     

    Regards,

    Aaron

  • In reply to Aaron Lee5:

    I'm having a very similar issue.  I am using the cc4000 with minimal setup.

    1) plug in vcc/ground

    2) plug in Tx to my serial connection (on my laptop)

    3) plug in reset to vcc, wait 10 seconds

    4) plug in push_to_fix to vcc

    I have tried this outdoors with no obstruction, and here is what i receive:

    $GPGSV,4,1,13,14,15,164,,15,24,045,,08,03,328,,03,50,236,*7C
    $GPGSV,4,2,13,06,47,208,,21,30,114,,24,07,081,,07,,,31*4B
    $GPGSV,4,3,13,26,,,42,28,08,355,,09,16,032,30,19,53,279,*41
    $GPGSV,4,4,13,22,67,191,*43
    $GPGLL,,,,,,V,N*64
    $GPRMC,,V,,,,,,,,,,N*53
    $GPGGA,,,,,,0,,,,,,,,*66
    $GPVTG,,T,,M,,N,,K,N*2C
    $GPGSA,A,1,,,,,,,,,,,,,,,*1E

    It appears that I have 13 satellites, yet I am getting no other information.  What's might I be doing wrong?

    Thanks

  • In reply to kirk johnson:

    Hi Kirk,

    If you look carefully at the GSV message and read the fields, you will notice the SNRs of the satellites are the following:

    <blank>,<blank>,<blank>,<blank>

    <blank>,<blank>,<blank>,<blank>,

    42,<blank>,30,<blank>

    <blank>

     

    Unfortunately the reciever sometimes reports SVs that it does not have a signal on. Interference, in addition to signal level to the chip could also be a problem.

     

    Regards,

    Aaron

     

  • In reply to Aaron Lee5:

    Thank you for your explanation.  I have since been able to get it work and I get the SNRs as expected.  Thanks!