ESP-PPB
ESP-PPB is an open-source, wireless, battery-powered platform for distributed, phase-coherent Wi-Fi Channel State Information (CSI) capture. Built on the ESP32-C3 and the ESP-IDF framework using FreeRTOS and LwIP, it achieves sub-PPB clock alignment by disciplining a VCTCXO using Wi-Fi Fine Timing Measurement (FTM). This enables advanced wireless sensing applications like angle-of-arrival estimation and indoor localization without the need for wired synchronization.