Hello all,
We are working on a system to measure the time difference between events at different locations. To describe the hardware briefly, our system is composed of dispersed modules equipped with MCU that manages all the module functionality and communicates through UART with the RAK3172 working in P2P mode. The main principle of these modules is to send information about events (GPIO change at MCU) wirelessly.
Then, there is another module that collects data from the air and calculates the time difference between particular signals. Our goal is to measure tens of seconds with a precision of at least 0.1 ms.
While tuning the performance of the system, we have observed that we can not reliably measure time differences with a precision better than 1 ms, as the RX frames on the air monitoring module arrive in moments rounded to about 1 ms periods. Looks like there is some scheduler managing events in a 1 ms loop but I went through the RUI3 code, and I can not localize anything like that.
Could you please advise me on the following points?
- Is it doable with RAK3172 modules to achieve such P2P transmission time repeatability that after its subtraction we can measure time with 100 us precision?
- This 1 ms quantization, it is done at the transmitter side, receiver side, or maybe on both ends of the transmission?
- Based on your experience, could you please share your idea of where you would start with the custom code to get a 0.1 ms resolution?