Digital front end for satellite LEO applications on W band

We present an Earth digital receiver for LEO satellite applications in W band (80-90 GHz), in order to design an architecture robust to frequency offset. The maximum Doppler frequency is proportional to the relative speed and the carrier frequency, therefore in W band this value is large, approximately 2 MHz. According to this phenomenon, the recovery of the received signal carrier is very difficult. Starting from the IF (intermediate frequency) stage, we present a digital method to estimate and correct the Doppler-shift directly in the base band. In particular, we propose an innovative algorithm based on a two step Doppler-recovery. We also provide simulation results indicating the accuracy of this method and a prototype system (based around DSP C6416) for real time carrier recovery with unknown Doppler-shift.