Design of a Baseband Signal for the 406 MHz Satellite Emergency Radio Transmitter Based on STM32

The baseband signal of the 406 MHz COSPAS-SARSAT emergency beacon is a 144-bit or 112-bit data with 0 and 1 code, including information bits error correcting check bits. In order to improve coding efficiency for transmitter in STM32 micro-controller, this paper proposes calculation method first BCH code (BCH-1) second (BCH-2) COSPAS-SARAST transmitter. First, conduct process by 64-bit integral data; then, compute (127, 106) (63, 51) obtain respective codes improving rate; next, generate according GB 14391-2021 format; finally, modulate into MHz-RF signal, send it out complete task distress alerting. experimental results show that proposed microcontroller-based generation effective, EPIRB (Emergency Position Indicating Radio Beacon) designed based on has reached industry standard.