Inquiry Regarding Timing Advance Calculation and Firmware Behavior on BG77 IoT Module

IoT Modules LPWA Module
1

Hey,

I am currently using the BG77 IoT module on a Cat M1 network.
Recently, I was asked to include the AT+QNWCFG="ta" command to obtain the Timing Advance (TA) value, allowing me to determine the distance from the cellular tower. So far, I have used the formula TA value * 78.5 meters for this calculation. Could you confirm if this is the most accurate formula or suggest a better alternative?

Additionally, I used my EVB with firmware version BG77LAR02A04_01.002.01.002, and the TA values were retrieved correctly. However, after updating the firmware to versions BG77LAR02A04_01.204.01.204 and BG77LAR02A04_01.206.01.206, I consistently received a TA value of 0 until I executed the command AT+QCFG="dbgctl",0. Could you please explain why this command resolves the issue and whether it is the correct approach?

2

Sorry I have no idea if the formula is accurate,because this is the operator’s internal algorithm.And the second answer is that when you executed the command AT+QCFG="dbgctl",0,the module enable the log function and extract the TA value from the log.