The invention relates to a 
satellite-borne tripe-frequency 
beacon and a working method thereof. The 
satellite-borne tripe-frequency 
beacon comprises an emitter, an emission antenna and a radio-frequency connection cable, wherein the radio-frequency connection cable is arranged between the emitter and the emission antenna, the emitter comprises a constant temperature 
crystal oscillator and a frequency source unit, the frequency source unit is electrically connected with the constant temperature 
crystal oscillator, coherent signals, generated by the frequency source unit, at VHF, UHF and L bandsare orthogonalized by a bridge and then synthesized and amplified by a power 
amplifier to output an I / Q 
signal, a lower 
computer management circuit for controlling each part in the emitter to work communicates with a 
satellite service through a 
CAN bus, and a 
power unit supplies power to each part in the emitter. With the satellite-borne tripe-frequency 
beacon disclosed by the invention, three coherent signals at the VHF, UHF and L bands can be initially and simultaneously emitted, the problem of 
electromagnetic compatibility of the tripe-frequency beacon and a GNSS 
occultation receiver is solved, the problem of in-band interference of the GNSS 
occultation receiver is effectively solved, normal working of the beacon is ensured, and meanwhile, normal working of the GNSS 
occultation receiver is not affected.