This paper describes the structure and design method in detail for the GPS/BDS of airborne equipment. In the baseband processing parts, the acquisition algorithm based on PMF-FFT is presented. Baseband processing circuit mainly complete the collection, the digital filtering, the signal processing and function calculating of intermediate frequency signal that from RF channel. GPS airborne equipment has the ability of satellite navigation system, meanwhile has the capability of compatible with GPS, BDS and GLONASS. The equipment has ability of receiving almanac and ephemeris of satellite navigation system, the original measurement data output, RAIM processing, difference processing, a variety of data format output, BIT system self-checking, status display and so on.