Delay calibration system for a two way satellite time & frequency transfer station

Abstract

A completely automated system has been designed to calibrate path delays in a two way satellite time and frequency transfer (TWSTFT) ground station. The heart of this delay calibration system is a dual bidirectional up/down converter that converts the modulated pseudo random noise (PRN) code from 70 MHz to Ku-band (10 GHz to 14 GHz) frequencies and vice versa. Besides the usual transmit (Tx) and receive (Rx) paths in the TWSTFT system, the dual bi-directional up/down converter offers two additional independent transmit and receive paths. These additional paths allow performing different independent loop delay measurements within the station from which the individual path delays can be calculated.