# WP7702 Issue Between Radio and GNSS **URL:** \ **Category:** IoT Modules\ **Created:** [October 15, 2021, 1:10am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207 "2021-10-15T01:10:02Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [October 15, 2021, 1:10am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/1 "2021-10-15T01:10:02Z")
I have been having issues with the GNSS on the WP7702 where the a position fix stops being reported in our app. I have finally narrowed this done to an interaction with the radio and the GNSS which has been identified earlier this year in this [post](https://forum.mangoh.io/t/strange-correlation-between-le-gnss-and-radio/9288). It appears that if the modem loses a connection to the network or is turned off with a `cm radio off` command the GNSS position fixes are no longer reported even though a `gnss get status` reports `active`. A `gnss get agpsMode` reports `Standalone agps mode`. Sending an `AT!GPSFIX=1,255,50` I see a single fix report in the logs but the portion fix reports don’t occur at the 1Hz rate it was before the network connect was lost. A `gnss start` seems to cause the GNSS to start producing position reports at the selected 1Hz rate. How do I stop this behaviour? We have been using the WP8548 and it doesn’t exhibit this behaviour. Our product requires constant GNSS fixes regardless of the state of the network connection. Also is this behaviour documented, it has been incredibly frustrating attempting to track down this issue. Thanks, ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 15, 2021, 2:24am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/2 "2021-10-15T02:24:16Z")
with WP77 module FW 14, if network lost, I can see there is NMEA data at 1Hz at “cat /dev/nmea” after AT!GPSFIX=1,255,50 ```auto root@fx30:~# cm radio Power: ON Current Network Operator: Current RAT: Module not registered on network, RAT not available Status: Not registered and not currently searching for new operator (LE_MRC_REG_NONE) Signal: No signal strength (0) PS: Packet Switched Not registered (LE_MRC_REG_NONE) root@fx30:~# cm info Device: WP7702 IMEI: 352653090002791 IMEISV: 6 FSN: VU735370340201 Firmware Version: SWI9X06Y_02.36.06.00 63d944 jenkins 2020/12/10 19:12:28 Bootloader Version: SWI9X06Y_02.36.06.00 63d944 jenkins 2020/12/10 19:12:28 MCU Version: 002.015 PRI Part Number (PN): 9907365 PRI Revision: 001.001 Carrier PRI Name: GENERIC Carrier PRI Revision: 001.071_001 SKU: 1103530 Last Reset Cause: Reset, User Requested Resets Count: Expected: 388 Unexpected: 28 root@fx30:~# cat /dev/nmea $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 ^C ``` ---
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [October 15, 2021, 3:06am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/3 "2021-10-15T03:06:01Z")
@jyijyi Thank you for prompt reply. I don’t have the device with me at home but I will check what `cat /dev/nmea` is producing tomorrow. I do have a some follow up questions. 1. Was your test run after power up? I ask because the GNSS provides position fixes after power up with no network connection as I would expect. The issue occurs when the network is lost after having a connection. I see the following in the logs. The `New Position sample` is my debug statement denoting the call to the position handler I registered with `le_gnss_AddPositionHandler`. ```auto Oct 9 06:51:07 swi-mdm9x28-wp user.info Legato: INFO | gpsMonitor[1757]/location T=main | location.c PositionHandlerFunction() 417 | New Position sample 0x12f Oct 9 06:51:08 swi-mdm9x28-wp user.info Legato: INFO | gpsMonitor[1757]/location T=main | location.c PositionHandlerFunction() 417 | New Position sample 0x12f Oct 9 06:51:09 swi-mdm9x28-wp user.info Legato: INFO | gpsMonitor[1757]/location T=main | location.c PositionHandlerFunction() 417 | New Position sample 0x12f Oct 8 23:51:09 swi-mdm9x28-wp user.info Legato: INFO | dcsDaemon[1710]/dcsCellular T=main | dcsCellular.c DcsCellularPacketSwitchHandler() 726 | Packet switch state: previous 4, new 0 Oct 8 23:51:09 swi-mdm9x28-wp user.info Legato: INFO | dcsDaemon[1710]/dcs T=main | dcs_db.c le_dcs_EventNotifierTechStateTransition() 311 | Notify all channels of technology 2 of system state transition to down Oct 8 23:51:09 swi-mdm9x28-wp user.info Legato: INFO | sensorToCloud[1858]/avPublisher T=main | avPublisher.c netRegStateHandle() 1039 | Network Registration state changed: [0:LE_MRC_REG_NONE] Oct 8 23:51:09 swi-mdm9x28-wp user.warn kernel: [399320.454618] PSM: Modem oprt mode - 6 Oct 8 23:51:09 swi-mdm9x28-wp user.warn Legato: -WRN- | posDaemon[1812]/le_pa_gnss T=unknown | pa_gnss_qmi.c PositionHandler() 1509 | Bad position indication Oct 8 23:51:09 swi-mdm9x28-wp user.warn Legato: -WRN- | modemDaemon[1775]/le_pa T=main | pa_sim_qmi.c MapSimState() 952 | More than one application 2 Oct 8 23:53:09 swi-mdm9x28-wp user.info Legato: INFO | modemDaemon[1775]/le_pa T=main | pa_mrc_qmi.c pa_mrc_GetNetworkRegState() 2482 | called ``` 1. If the GNSS is producing a fix via the `cat /dev/nmea` file then why does the position hander that was registered with a `le_gnss_AddPositionHandler` call in my Legato app stop being called. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 15, 2021, 3:10am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/4 "2021-10-15T03:10:58Z")
my setup does not have SIM card, so it would not have network connection ---
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [October 15, 2021, 4:52am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/5 "2021-10-15T04:52:13Z")
@jyijyi As I said above and as described in the linked post the GNSS position fix is fine at start up without a connection to the network. The issue seems to occur when moving from a connected state to an unconnected state. Honestly, stating that it works for you isn’t very constructive when I’m trying to help understand the cause of the issue and determine how to over come it. Thanks ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 15, 2021, 5:15am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/6 "2021-10-15T05:15:34Z")
I don’t quite agree, at least you will know someone’s setup works fine and you can isolate with different factors like hardware, fw version or network afterwards FYI, no problem is found for network drop ```auto root@fx30:~# pwd /home/root root@fx30:~# cm radio Power: ON Current Network Operator: USIM Current RAT: LTE network (LE_MRC_RAT_LTE) Status: Registered, home network (LE_MRC_REG_HOME) Signal: Very strong signal strength (5) PS: Packet Switched Registered, home network (LE_MRC) root@fx30:~# cm radio Power: ON Current Network Operator: Current RAT: Module not registered on network, RAT not availae Status: Not registered and not currently searching for n) Signal: No signal strength (0) PS: Packet Switched Not registered (LE_MRC_REG_NONE) root@fx30:~# cat /dev/nmea ^C root@fx30:~# microcom /dev/ttyAT AT!GPSFIX=1,255,50 OK root@fx30:~# cat /dev/nmea $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 $GPVTG,,T,,M,,N,,K,N*2C $GPGSA,A,1,,,,,,,,,,,,,,,,*32 $GPGRS,,,,,,,,,,,,*51 $GPGLL,,,,,,*50 $GPGGA,,,,,,0,,,,,,,,*66 $PQXFI,,,,,,,,,,*56 $GPRMC,,V,,,,,,,,,,N,V*29 $GPGLL,,,,,,*50 ^C ``` ---
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [October 15, 2021, 6:42pm UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/7 "2021-10-15T18:42:02Z")
@jyijyi I can in this morning and ran the same commands as you above. Before doing this I ran a `gnss get status` to which shows as `active`. Here is my `cm info`: ```auto Device: WP7702 IMEI: XXXXXXXX IMEISV: 6 FSN: XXXXXXXXX Firmware Version: SWI9X06Y_02.36.06.00 63d944 jenkins 2020/12/10 19:12:28 Bootloader Version: SWI9X06Y_02.36.06.00 63d944 jenkins 2020/12/10 19:12:28 MCU Version: 002.015 PRI Part Number (PN): 9908741 PRI Revision: 002.001 Carrier PRI Name: GENERIC Carrier PRI Revision: 001.071_001 SKU: 1104214 Last Reset Cause: Reset, User Requested Resets Count: Expected: 12 Unexpected: 0 ``` I get no output when running `cat /dev/nmea` until I run a `gnss stop` followed by a `gnss start` only then do is see data from the `cat /dev/nmea` command. I did further testing with the follow scenarios and they both result in the gnss position fix stopping confirmed by watching `cat /dev/nmea` **Test 1** (Active Network Connection): I have an active network connection, the gnss is producing a fix and then I remove the antenna. The fix continues while the modem is searching once the modem moves into `Packet Switched Not registered (LE_MRC_REG_NONE)` then the gnss fix stops and the logs show this: ```auto Oct 15 10:29:04 swi-mdm9x28-wp user.warn kernel: [71828.509868] PSM: Modem oprt mode - 6 Oct 15 10:29:04 swi-mdm9x28-wp user.warn Legato: -WRN- | posDaemon[1808]/le_pa_gnss T=unknown | pa_gnss_qmi.c PositionHandler() 1509 | Bad position indication Oct 15 10:29:04 swi-mdm9x28-wp user.info Legato: INFO | dcsDaemon[1703]/dcsCellular T=main | dcsCellular.c DcsCellularPacketSwitchHandler() 726 | Packet switch state: previous 4, new 0 Oct 15 10:29:04 swi-mdm9x28-wp user.info Legato: INFO | dcsDaemon[1703]/dcs T=main | dcs_db.c le_dcs_EventNotifierTechStateTransition() 311 | Notify all channels of technology 2 of system state transition to down ``` I’m not sure how PSM is being entered as I have PSM disabled. **Test 2** (Manually Disable the Radio): I have an active network connection, the gnss is producing a fix and then I remove the antenna. The fix continues until the modem is turned off via `cm radio off` then is see the same messages as the above log. In both tests the `gnss get state` reports as `active`, the GNSS is in standalone mode and PSM is disabled. Is this enough detail to reproduce the error? Thanks, ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 15, 2021, 11:44pm UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/8 "2021-10-15T23:44:46Z")
I remember that if gnss is needed by at!gpsfix command, you cannot turn off the radio According to your test, you can restart gnss if network lost happens ---
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [October 16, 2021, 1:07am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/9 "2021-10-16T01:07:37Z")
@jyijyi Is this interaction with the radio and GNSS documented anywhere? The WP8548 doesn’t seem to have the same interaction. Thanks, ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [October 16, 2021, 2:37am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/10 "2021-10-16T02:37:31Z")
I don’t know, but i just try to find a way for you to make it work Wp85 and wp77 are using different chipset, so we might not have direct comparison between them ---
**Author:** ![gi1](https://avatars.discourse-cdn.com/v4/letter/g/e79b87/32.png) [@gi1](https://forum.sierrawireless.com/u/gi1)\ **Post date:** [June 18, 2024, 3:04pm UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/11 "2024-06-18T15:04:30Z")
Hello, I know this is an old post, but did you find any valid solution to this problem? Actually in our firmware we force a stop and start every time the network registration is lost. regards, Gianmaria ---
**Author:** ![dbeckwith](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/dbeckwith/32/4479_2.png) [@dbeckwith](https://forum.sierrawireless.com/u/dbeckwith)\ **Post date:** [June 18, 2024, 9:26pm UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/12 "2024-06-18T21:26:35Z")
Hi Gianmaria, No I didn’t find a suitable solution unfortunately. Darren ---
**Author:** ![gi1](https://avatars.discourse-cdn.com/v4/letter/g/e79b87/32.png) [@gi1](https://forum.sierrawireless.com/u/gi1)\ **Post date:** [June 19, 2024, 8:39am UTC](https://forum.sierrawireless.com/t/wp7702-issue-between-radio-and-gnss/25207/13 "2024-06-19T08:39:19Z")
Thanks for your reply. Ok.