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Unable to get GPS fix with GPS samples

Hi,

I am trying to get a GPS reading on the NRF9160DK. I have tried both the GPS sample (no SUPL client) and the A-GPS sample, but with neither sample projects I manage to get a GPS fix.

Information:

- NCS: v1.7.1

- MFW: mfw_nrf9160_1.3.1

- Sim card: iBasis

- DK version: 1.0.0

- Location: Noord-Brabant, The Netherlands

I have tried the following: 
- GPS sample: Both indoors and outdoors in open sky (very cloudy weather), tried both with external antenna enabled and disabled. All test gave the same output.

Output: 

*** Booting Zephyr OS build v2.6.99-ncs1-1  ***
Starting GPS sample
Getting GNSS data...
Tracking: 0 Using: 0 Unhealthy: 0
---------------------------------
Seconds since last fix: 1
Searching [|]

NMEA strings:

$GPGGA,000001.00,,,,,0,,99.99,,M,,M,,*67
$GPGLL,,,,,000001.00,V,N*4B
$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,1*2D
$GPGSV,1,1,0,,,,,,,,,,,,,,,,,1*54
$GPRMC,000001.00,V,,,,,,,060180,,,N,V*09
Tracking: 0 Using: 0 Unhealthy: 0
---------------------------------
Seconds since last fix: 2

Tracking: 2 Using: 0 Unhealthy: 0

---------------------------------

Seconds since last fix: 110

Searching [/]

NMEA strings:

$GPGGA,000150.00,,,,,0,,99.99,,M,,M,,*62

$GPGLL,,,,,000150.00,V,N*4E

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

$GPGSV,1,1,2,1,,,25,31,,,24,1*64

$GPRMC,000150.00,V,,,,,,,060180,,,N,V*0C

Tracking: 1 Using: 0 Unhealthy: 0

---------------------------------

Seconds since last fix: 111

Searching [-]

NMEA strings:

$GPGGA,000151.00,,,,,0,,99.99,,M,,M,,*63

$GPGLL,,,,,000151.00,V,N*4F

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

$GPGSV,1,1,1,31,,,24,1*51

$GPRMC,000151.00,V,,,,,,,060180,,,N,V*0D

- AGPS sample: Both indoors and outdoors in open sky (very cloudy weather). Both test gave the same result.

Output:

*** Booting Zephyr OS build v2.6.99-ncs1-1  ***
I: A-GPS sample has started
I: Connecting to LTE network. This may take minutes.
I: PSM mode requested
+CEREG: 2,"FAC9","007C6B0B",7
+CSCON: 1
+CEREG: 1,"FAC9","007C6B0B",7,,,"00000010","00011111"
I: Connected to LTE network
D: MAGPIO set: AT%XMAGPIO=1,0,0,1,1,1565,1586
D: COEX0 set: AT%XCOEX0=1,1,1565,1586
I: CLOUD_EVT_CONNECTING
I: CLOUD_EVT_CONNECTED
I: CLOUD_EVT_PAIR_DONE
E: Failed to save session state: -2
I: CLOUD_EVT_READY
I: Service info sent to cloud
D: GPS mode is enabled
D: GPS operational
I: Periodic GPS search started with interval 240 s, timeout 120 s
I: GPS_EVT_SEARCH_STARTED
D: A-GPS data update needed
I: GPS_EVT_AGPS_DATA_NEEDED
D: Waiting for time window to operate
I: GPS_EVT_OPERATION_BLOCKED
I: CLOUD_EVT_DATA_RECEIVED
D: Received AGPS data. Schema version: 1, length: 1160
D: A-GPS_injection_active LOCKED
D: Using GPS driver to input assistance data
D: Parsed_len: 35
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 1
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 66
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 2
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 97
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 3
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 128
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 4
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 159
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 5
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 190
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 6
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 221
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 7
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 252
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 8
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 283
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 9
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 314
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 10
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 345
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 11
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 376
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 12
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 407
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 13
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 438
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 14
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 469
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 15
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 500
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 16
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 531
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 17
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 562
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 18
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 593
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 19
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 624
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 20
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 655
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 21
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 686
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 22
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 717
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 23
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 748
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 24
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 779
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 25
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 810
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 26
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 841
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 27
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 872
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 29
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 903
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 30
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 934
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 31
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 965
D: A-GPS type: NRF_CLOUD_AGPS_ALMANAC 32
D: Sent A-GPS data to modem, type: 3
D: Parsed_len: 972
D: TOW 0 copied
D: Parsed_len: 976
D: TOW 1 copied
D: Parsed_len: 980
D: TOW 2 copied
D: Parsed_len: 984
D: TOW 3 copied
D: Parsed_len: 988
D: TOW 4 copied
D: Parsed_len: 992
D: TOW 5 copied
D: Parsed_len: 996
D: TOW 6 copied
D: Parsed_len: 1000
D: TOW 7 copied
D: Parsed_len: 1004
D: TOW 8 copied
D: Parsed_len: 1008
D: TOW 9 copied
D: Parsed_len: 1012
D: TOW 11 copied
D: Parsed_len: 1016
D: TOW 12 copied
D: Parsed_len: 1020
D: TOW 13 copied
D: Parsed_len: 1024
D: TOW 14 copied
D: Parsed_len: 1028
D: TOW 15 copied
D: Parsed_len: 1032
D: TOW 16 copied
D: Parsed_len: 1036
D: TOW 17 copied
D: Parsed_len: 1040
D: TOW 18 copied
D: Parsed_len: 1044
D: TOW 19 copied
D: Parsed_len: 1048
D: TOW 20 copied
D: Parsed_len: 1052
D: TOW 21 copied
D: Parsed_len: 1056
D: TOW 22 copied
D: Parsed_len: 1060
D: TOW 23 copied
D: Parsed_len: 1064
D: TOW 24 copied
D: Parsed_len: 1068
D: TOW 25 copied
D: Parsed_len: 1072
D: TOW 26 copied
D: Parsed_len: 1076
D: TOW 28 copied
D: Parsed_len: 1080
D: TOW 29 copied
D: Parsed_len: 1084
D: TOW 30 copied
D: Parsed_len: 1088
D: TOW 31 copied
D: Parsed_len: 1107
D: TOWs copied, bitmask: 0xf7fffbff
D: A-GPS type: NRF_CLOUD_AGPS_GPS_SYSTEM_CLOCK
D: Sent A-GPS data to modem, type: 7
D: Parsed_len: 1125
D: A-GPS type: NRF_CLOUD_AGPS_LOCATION
D: Sent A-GPS data to modem, type: 8
D: Parsed_len: 1142
D: A-GPS type: NRF_CLOUD_AGPS_UTC_PARAMETERS
D: Sent A-GPS data to modem, type: 1
D: Parsed_len: 1153
D: A-GPS type: NRF_CLOUD_AGPS_KLOBUCHAR_CORRECTION
D: Sent A-GPS data to modem, type: 4
D: Parsed_len: 1160
D: A-GPS type: NRF_CLOUD_AGPS_INTEGRITY
D: Sent A-GPS data to modem, type: 9
D: A-GPS_inject_active UNLOCKED
I: A-GPS data successfully processed
I: A-GPS data processed
I: CLOUD_EVT_DATA_RECEIVED
D: Received AGPS data. Schema version: 1, length: 1864
D: A-GPS_injection_active LOCKED
D: Using GPS driver to input assistance data
D: Parsed_len: 66
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 1
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 128
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 2
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 190
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 3
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 252
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 4
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 314
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 5
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 376
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 6
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 438
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 7
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 500
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 8
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 562
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 9
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 624
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 10
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 686
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 12
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 748
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 13
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 810
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 14
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 872
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 15
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 934
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 16
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 996
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 17
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1058
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 18
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1120
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 19
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1182
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 20
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1244
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 21
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1306
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 22
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1368
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 23
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1430
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 24
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1492
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 25
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1554
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 26
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1616
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 27
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1678
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 29
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1740
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 30
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1802
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 31
D: Sent A-GPS data to modem, type: 2
D: Parsed_len: 1864
D: A-GPS type: NRF_CLOUD_AGPS_EPHEMERIDES 32
D: Sent A-GPS data to modem, type: 2
D: A-GPS_inject_active UNLOCKED
I: A-GPS data successfully processed
I: A-GPS data processed
D: GPS priority enabled

D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1770
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1771
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1772
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1773
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1774
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1775
I: Tracking: 7  9
D: Tracking SV  7: not used,     healthy
D: Tracking SV  9: not used,     healthy
D: Tracking: 2 Using: 0 Unhealthy: 0
D: Seconds since last fix 1776
I: Tracking: 7  9  14
D: Tracking SV  7: not used,     healthy
D: Tracking SV  9: not used,     healthy
D: Tracking SV 14: not used,     healthy
D: Tracking: 3 Using: 0 Unhealthy: 0
D: Seconds since last fix 1778
D: Tracking SV  7: not used,     healthy
D: Tracking SV  9: not used,     healthy
D: Tracking SV 14: not used,     healthy
D: Tracking: 3 Using: 0 Unhealthy: 0
D: Seconds since last fix 1779
D: Tracking SV  7: not used,     healthy
D: Tracking SV  9: not used,     healthy
D: Tracking SV 14: not used,     healthy
D: Tracking: 3 Using: 0 Unhealthy: 0
D: Seconds since last fix 1780
I: Tracking: 14  18
D: Tracking SV 18: not used,     healthy
D: Tracking SV 14: not used,     healthy
D: Tracking: 2 Using: 0 Unhealthy: 0
D: Seconds since last fix 1780
I: Tracking: 18
D: Tracking SV 18: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1781
D: Tracking SV 18: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1782
D: Tracking SV 18: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1783
D: Tracking: 0 Using: 0 Unhealthy: 0
D: Seconds since last fix 1784
I: Tracking: 7
D: Tracking SV  7: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1785
D: Tracking SV  7: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1786
D: Tracking SV  7: not used,     healthy
D: Tracking: 1 Using: 0 Unhealthy: 0
D: Seconds since last fix 1787
I: Tracking: 7  28
D: Tracking SV  7: not used,     healthy
D: Tracking SV 28: not used, not healthy
D: Tracking: 2 Using: 0 Unhealthy: 1
D: Seconds since last fix 1788
I: Tracking: 28
D: Tracking SV 28: not used, not healthy
D: Tracking: 1 Using: 0 Unhealthy: 1
D: Seconds since last fix 1789
D: Tracking SV 28: not used, not healthy
D: Tracking: 1 Using: 0 Unhealthy: 1
D: Seconds since last fix 1790
D: Tracking SV 28: not used, not healthy
D: Tracking: 1 Using: 0 Unhealthy: 1
D: Seconds since last fix 1791
D: Tracking: 0 Using: 0 Unhealthy: 0

Parents
  • Hi,

    Based on the log from the GPS sample, it doesn't look like the DK was able to receive strong enough signals from the satellites.

    In the following NMEA sentence, we can see that it has found 2 satellites (PRNs 1 and 31), though the signal to noice ratio is too low for the GPS to calculate their elevation or azimuth.

    $GPGSV,1,1,2,1,,,25,31,,,24,1*64

    The GPS would also need to track at least 4 satellites to produce a fix.

    The AGPS sample doesn't print the satellite SNRs, but my guess is that the same thing happens. the SNR of the satellites it finds are too low, and it finds too few satellites.

    Getting a fix indoors is generally quite hard (not completely impossible, but also not something you should expect to happen). When testing outdoors, you should also try to be in a spot with a clear view of the sky, and as little as possible obstructing the view of the horizon. Tall buildings can create the same problems as a deep canyon.

    Best regards,

    Didrik

Reply
  • Hi,

    Based on the log from the GPS sample, it doesn't look like the DK was able to receive strong enough signals from the satellites.

    In the following NMEA sentence, we can see that it has found 2 satellites (PRNs 1 and 31), though the signal to noice ratio is too low for the GPS to calculate their elevation or azimuth.

    $GPGSV,1,1,2,1,,,25,31,,,24,1*64

    The GPS would also need to track at least 4 satellites to produce a fix.

    The AGPS sample doesn't print the satellite SNRs, but my guess is that the same thing happens. the SNR of the satellites it finds are too low, and it finds too few satellites.

    Getting a fix indoors is generally quite hard (not completely impossible, but also not something you should expect to happen). When testing outdoors, you should also try to be in a spot with a clear view of the sky, and as little as possible obstructing the view of the horizon. Tall buildings can create the same problems as a deep canyon.

    Best regards,

    Didrik

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