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nRF9160 > GPS > RSSI?

Dear Team,

Is it or will it be possible to get an RSSI info like we used to in nRF5?

Best

Oleh

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  • Hi,

     

    For the GNSS, there is a C/N0 (carrier to noise density, more details here) field:

    https://github.com/NordicPlayground/nrfxlib/blob/master/bsdlib/include/nrf_socket.h#L511

     

    For the LTE part, you can get the RSRP (ref. signal received power) through AT command AT+CESQ, where the last number is a reference from -140 dBm. If you get "40", it would indicate -140 + 40 = -100 dBm signal.

     

    Kind regards,

    Håkon 

  • Hi Håkon,

    nice to hearing from you again!

    Thanks for the link to nrf_gnss_sv_t struct, it sounds promissing :)

    A short confirmation question: will these data be available only with the fix? Or could be accessed even if no fix is (still) available?

    ... trying to get the RSSI while Position-Reposition the device... in-/out-door...

    also, thanks for the AT+CESQ info.

    Best regards

    Oleh

  • Hi Oleh,

     

    Oleh said:

    nice to hearing from you again!

    Likewise!

    Without a fix, its not available.

     

    Kind regards,

    Håkon

  • Hi Håkon,

    thank you for your Reply!

    ... you know... it would be nice to have that available: just a Feature request ;)

    Best regards

    Oleh 

  • Hi Håkon,

    just a short from the field test...

    I get the NMEA sentences without fix, these are not fully filled:

    dump_gnss_data_frames > NMEA data
    NMEA strings:
    $GPGGA,000000.00,,,,,0,,99.99,,M,0,,*37

    $GPGGA,000618.00,,,,,0,02,99.99,,M,0,,*3A

    $GPGLL,,,,,000618.00,V,A*4A

    $GPGLL,,,,,000617.00,V,A*45

    $GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,1*2D

    $GPGSV,1,1,2,6,,,28,7,,,22,1*5D

    $GPGSV,1,1,2,6,,,26,7,,,20,1*51

    here, for the cn0 especially GPGSV is interesting, as we get sat info.

    then I got PositionVelocityTime data:


    dump_gnss_data_frames > PVT data
    SV:6 cn0:65281 Sig:1 eL:0 Az:0 Flags:0
    SV:2 cn0:15873 Sig:3 eL:1 Az:0 Flags:0
    SV:4 cn0:2561 Sig:9 eL:1 Az:0 Flags:0
    SV:7 cn0:11521 Sig:3 eL:1 Az:0 Flags:0
    - Tracking: 4 Using: 0 Unhealthy: 0

    Still no fix.... then getting more info:

    $GPGSV,2,1,5,6,54,241,29,2,35,302,30,4,68,257,29,7,43,168,29,1*5A

    $GPGSV,2,2,5,5,05,298,27,1*57

    (so 5 sats)

    and finally fix:

    dump_gnss_data_frames > PVT data
    SV:6 cn0:10497 Sig:3 eL:13825 Az:-3840 Flags:0
    SV:2 cn0:12801 Sig:3 eL:8961 Az:11776 Flags:1
    SV:4 cn0:8961 Sig:9 eL:17409 Az:256 Flags:1
    SV:7 cn0:10753 Sig:3 eL:11009 Az:-22528 Flags:0
    SV:5 cn0:4353 Sig:3 eL:1281 Az:10752 Flags:1
    - Tracking: 5 Using: 3 Unhealthy: 0

    ... so I find this "filling values" good, probably side-effect, but it gives some info even before fix.

    Thanks and best 

    Oleh

Reply
  • Hi Håkon,

    just a short from the field test...

    I get the NMEA sentences without fix, these are not fully filled:

    dump_gnss_data_frames > NMEA data
    NMEA strings:
    $GPGGA,000000.00,,,,,0,,99.99,,M,0,,*37

    $GPGGA,000618.00,,,,,0,02,99.99,,M,0,,*3A

    $GPGLL,,,,,000618.00,V,A*4A

    $GPGLL,,,,,000617.00,V,A*45

    $GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,1*2D

    $GPGSV,1,1,2,6,,,28,7,,,22,1*5D

    $GPGSV,1,1,2,6,,,26,7,,,20,1*51

    here, for the cn0 especially GPGSV is interesting, as we get sat info.

    then I got PositionVelocityTime data:


    dump_gnss_data_frames > PVT data
    SV:6 cn0:65281 Sig:1 eL:0 Az:0 Flags:0
    SV:2 cn0:15873 Sig:3 eL:1 Az:0 Flags:0
    SV:4 cn0:2561 Sig:9 eL:1 Az:0 Flags:0
    SV:7 cn0:11521 Sig:3 eL:1 Az:0 Flags:0
    - Tracking: 4 Using: 0 Unhealthy: 0

    Still no fix.... then getting more info:

    $GPGSV,2,1,5,6,54,241,29,2,35,302,30,4,68,257,29,7,43,168,29,1*5A

    $GPGSV,2,2,5,5,05,298,27,1*57

    (so 5 sats)

    and finally fix:

    dump_gnss_data_frames > PVT data
    SV:6 cn0:10497 Sig:3 eL:13825 Az:-3840 Flags:0
    SV:2 cn0:12801 Sig:3 eL:8961 Az:11776 Flags:1
    SV:4 cn0:8961 Sig:9 eL:17409 Az:256 Flags:1
    SV:7 cn0:10753 Sig:3 eL:11009 Az:-22528 Flags:0
    SV:5 cn0:4353 Sig:3 eL:1281 Az:10752 Flags:1
    - Tracking: 5 Using: 3 Unhealthy: 0

    ... so I find this "filling values" good, probably side-effect, but it gives some info even before fix.

    Thanks and best 

    Oleh

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