Drone Time Synchronization and Communication: A Dual-Module Based on ESP8266 and HC-12

This paper presents the design, implementation, and validation of a communication subsystem for an autonomous drone which could meet the requirements of high-precision time synchronization and reliable data transmission in a GPS-denied indoor environment. The developed system employs a dual-module architecture: an ESP8266 Wi-Fi module acquires accurate time by Wi-Fi, while an HC-12 wireless module to transmit data for mission verification. To address the OpenMV’s UART port limitations, we adopted an architecture with the flight controller acting as a data relay. We also designed a custom communication protocol incorporating a checksum to guarantee the integrity of data transmitted between modules. Experimental results show a $94 \%$ single-attempt success rate for the 0.1 s update cycle in wireless reception at 5 meters. This high repetition rate with the high individual success rate guarantees an almost $100 \%$ success rate within a 1-second timeframe. Comprehensive tests across varying distances confirm robustness, with latency averaging 50ms and time errors below 2.5ms, enabling seamless integration in dynamic indoor scenarios. For future work, we have a preliminary plan to address the current solution’s limitation in Wi-Fi-free environments by using the ESP8266 to calibrate an RTC module and could develop new functions by Wi-Fi module. This report shows that our design is stable and fully meets the project’s requirements with strong extensibility.