work around for NCSDK-14235: Timestamps that are sent in cloud messages drift over time

[Waqar Ahmed]

Hi Support,
we had recently upgraded our firmware to nrf Connect sdk1.9.0.

i read the following known issue for 1.9.0
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/known_issues.html?v=v1-9-0.

please can you confirm us is there any work around for the time drift problem in this sdk.

Thanks

[JONATHAN LL]

Due to summer holiday staffing is low and response time is slower than usual, pardon the inconvenience. 

We will get back to you as soon as we can. 

Regards,
Jonathan

[Waqar Ahmed]

LTE cell changed: Cell ID: 38517279, Tracking area: 9010
RRC mode: Connected
Network registration status: Connected - roaming
D: UpPSM parameter update: TAU: 4200, Active time: 60
connection_poll_started
Next connection retry in 30 seconds
dating date time UTC...
D: Date time never set
D: Getting time from cellular network
D: Modem has not got time from LTE network, so not using it
D: Getting time from NTP server
AWS_IOT_EVT_CONNECTING
D: Connected to LTE, performing NTP UTC time update
D: Date time never set
D: Time obtained from cellular network (XTIME notification)
D: System time updated: 2022-08-09 11:53:15
DATE_TIME_OBTAINED_MODEM
D: IPv4 Address found 54.194.240.240
D: Time obtained from NTP server ntp.uio.no
D: New date time update in: 14400 seconds
D: System time updated: 1970-01-01 00:00:00
DATE_TIME_OBTAINED_NTP
D: Updating date time UTC...
D: Using previously obtained time
DATE_TIME_OBTAINED_NTP
D: Using send socket timeout of 60 seconds
D: AWS IoT broker connection request sent
D: MQTT client connected!
MQTT client connected!AWS_IOT_EVT_CONNECTED

Current RSRP -125
Publishing: {
"state":{
"reported":{
"logging_interval":300,
"app_version":"v2.0.0",
"ts":16743,
"battery":3600,
"psu":0,
"imei":"",
"lat":53.335768,
"long":-6.325005,
"ttff":0,
"last_loc_update_time":0,
"current_network_mode":"NBIOT",
"rsrp":-125,
"rsrq":-12,
"nbiot_rsrp":-125,
"lte_m_rsrp":0
}
}
} to AWS IoT broker
message length 356

[Hakon]

The modem does not receive the network time the first time and then tried with NTP, which gives the wrong time. You can try setting CONFIG_DATE_TIME_AUTO_UPDATE and not run date_time_core_update_async(). If it doesn't work, try increasing the delay.

Also, the NTP server seems to be giving the wrong time, so it would be nice to have a modem trace to investigate this.