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  • Case ID: 333882
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GNSS Behavior with nRF9151 on Firmware v2.0.1

mrks115

Hi,

Since we started testing the new nRF9151 with the latest modem firmware (v2.0.1), we’ve noticed a change in GNSS behavior compared to the nRF9161/v1.3.6.

Recently, the number of tracked satellites increases rapidly to a high value, only to drop significantly after some time. I can observe this regularly. The previous behavior was a more gradual increase or decrease in the satellite count.

[00:06:18.570,495] <inf>  0 s - Tracking:  0     C/N0>0: 0       Using:  0       Unhealthy: 0
[00:06:19.561,187] <inf>  0 s - Tracking:  9     C/N0>0: 4       Using:  0       Unhealthy: 0
[00:06:20.563,323] <inf>  1 s - Tracking: 10     C/N0>0: 6       Using:  0       Unhealthy: 0
[00:06:21.563,720] <inf>  2 s - Tracking: 11     C/N0>0: 7       Using:  0       Unhealthy: 1
[00:06:22.590,637] <inf>  4 s - Tracking: 11     C/N0>0: 11      Using:  0       Unhealthy: 1
[00:06:23.592,681] <inf>  5 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:24.592,468] <inf>  6 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:25.591,766] <inf>  7 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:26.592,834] <inf>  8 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:27.593,963] <inf>  9 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:28.593,811] <inf> 10 s - Tracking: 11     C/N0>0: 11      Using:  2       Unhealthy: 1
[00:06:29.622,528] <inf> 11 s - Tracking: 11     C/N0>0: 11      Using:  4       Unhealthy: 1
[00:06:30.575,012] <inf> 12 s - Tracking:  2     C/N0>0: 2       Using:  2       Unhealthy: 0
[00:06:31.572,875] <inf> 13 s - Tracking:  2     C/N0>0: 2       Using:  2       Unhealthy: 0
[00:06:32.594,818] <inf> 14 s - Tracking:  4     C/N0>0: 4       Using:  2       Unhealthy: 0
[00:06:33.583,129] <inf> 15 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0

Is this expected behavior, or could there be an issue somewhere?

nRF Connect Version: 2.6.1

Best regards,
Markus

Parents
  • 0

    Hi Markus,

    Since we started testing the new nRF9151 with the latest modem firmware (v2.0.1), we’ve noticed a change in GNSS behavior compared to the nRF9161/v1.3.6.

    Did you test on your custom board or on the nrf9151-dk?

    Recently, the number of tracked satellites increases rapidly to a high value, only to drop significantly after some time. I can observe this regularly. The previous behavior was a more gradual increase or decrease in the satellite count.

    Is there a periodicity to the event you observed? What is the time interval between rapid increases of the number of satellites?

    Best regards,
    Dejan

Reply
  • 0

    Hi Markus,

    Since we started testing the new nRF9151 with the latest modem firmware (v2.0.1), we’ve noticed a change in GNSS behavior compared to the nRF9161/v1.3.6.

    Did you test on your custom board or on the nrf9151-dk?

    Recently, the number of tracked satellites increases rapidly to a high value, only to drop significantly after some time. I can observe this regularly. The previous behavior was a more gradual increase or decrease in the satellite count.

    Is there a periodicity to the event you observed? What is the time interval between rapid increases of the number of satellites?

    Best regards,
    Dejan

Children
  • 0 in reply to dejans

    Hi Dejan,

    Did you test on your custom board or on the nrf9151-dk?

    On our custom board, we currently don't have any 9151 devkits. Antenna performance, compared to nrf9160 devkit and other nrf9160 boards, is "very good", at least as good as on the other boards.

    Is there a periodicity to the event you observed? What is the time interval between rapid increases of the number of satellites?

    This happens every time we do a GNSS search. As far as I have observed it, the increase mostly happens after 10s, but not always, so I'm not sure if this is just a coincidence. Sometimes it is 6s, sometimes 2s (like in the sample above), etc.

    Most of the time it looks like the following (under okay-ish conditions near a window, but far away to not getting a valid fix in time):

    [00:15:05.109,191]  0 s - Tracking:  0     C/N0>0: 0       Using:  0       Unhealthy: 0
[00:15:06.094,146]  0 s - Tracking:  1     C/N0>0: 1       Using:  0       Unhealthy: 0
[00:15:07.096,130]  1 s - Tracking:  2     C/N0>0: 2       Using:  0       Unhealthy: 0
[00:15:08.096,343]  2 s - Tracking:  2     C/N0>0: 2       Using:  0       Unhealthy: 0
[00:15:09.098,205]  3 s - Tracking:  2     C/N0>0: 2       Using:  0       Unhealthy: 0
[00:15:10.096,405]  4 s - Tracking:  2     C/N0>0: 1       Using:  0       Unhealthy: 0
[00:15:11.097,381]  5 s - Tracking:  3     C/N0>0: 1       Using:  0       Unhealthy: 0
[00:15:12.096,496]  6 s - Tracking:  3     C/N0>0: 3       Using:  0       Unhealthy: 0
[00:15:13.098,968]  7 s - Tracking:  3     C/N0>0: 3       Using:  0       Unhealthy: 0
[00:15:14.099,975]  8 s - Tracking:  3     C/N0>0: 3       Using:  0       Unhealthy: 0
[00:15:15.100,372]  9 s - Tracking:  3     C/N0>0: 3       Using:  0       Unhealthy: 0
[00:15:16.118,865] 11 s - Tracking: 10     C/N0>0: 10      Using:  0       Unhealthy: 1
[00:15:16.901,153] 11 s - Tracking: 10     C/N0>0: 10      Using:  0       Unhealthy: 1
[00:15:17.903,686] 12 s - Tracking: 10     C/N0>0: 10      Using:  2       Unhealthy: 1
[00:15:18.904,815] 13 s - Tracking: 10     C/N0>0: 10      Using:  2       Unhealthy: 1
[00:15:19.905,120] 14 s - Tracking: 10     C/N0>0: 10      Using:  3       Unhealthy: 1
[00:15:20.906,646] 15 s - Tracking: 10     C/N0>0: 10      Using:  3       Unhealthy: 1
[00:15:21.918,823] 16 s - Tracking: 10     C/N0>0: 10      Using:  5       Unhealthy: 1
[00:15:22.917,846] 17 s - Tracking: 10     C/N0>0: 10      Using:  5       Unhealthy: 1
[00:15:23.885,955] 18 s - Tracking:  3     C/N0>0: 3       Using:  3       Unhealthy: 0
[00:15:24.887,603] 19 s - Tracking:  3     C/N0>0: 3       Using:  3       Unhealthy: 0
[00:15:25.888,031] 20 s - Tracking:  3     C/N0>0: 3       Using:  3       Unhealthy: 0
[00:15:26.891,510] 21 s - Tracking:  3     C/N0>0: 3       Using:  3       Unhealthy: 0
[00:15:27.909,454] 22 s - Tracking:  4     C/N0>0: 4       Using:  4       Unhealthy: 0
[00:15:28.906,097] 23 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:29.906,524] 24 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:30.889,221] 25 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:31.889,190] 26 s - Tracking:  4     C/N0>0: 3       Using:  3       Unhealthy: 0
[00:15:32.895,324] 27 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:33.894,653] 28 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:34.890,106] 29 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0
[00:15:35.893,280] 30 s - Tracking:  4     C/N0>0: 4       Using:  3       Unhealthy: 0

    Currently I'm testing with the latest Modem FW beta you gave me, it's still the same behavior.

    Best regards,
    Markus

  • +1 in reply to mrks115

    Hi Markus,

    What you observed is expected behavior when using modem firmware v2.0.1. We have already tuned tracked satellite reporting and this improved implementation will be included in modem firmware v2.0.2.

    Best regards,
    Dejan

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