Frequency recovery techniques for TM/TC satellite modem in critical scenarios

Reliability and effectiveness are essential features of satellite transceivers for telemetry and telecommand applications.Modem performance has a strong impact on the success of a satellite mission, in particular, during critical scenarios as the early operation phase, the disposal of a satellite at the end of its life, or the deep-spacemissions. In these specific mission critical scenarios, fast and correct data reception is even more important than high channel capacity. An unknown and fast variable channel condition, which can be caused by uncertain spacecraft attitude and large Doppler shift with respect to the data rate, requires efficient and innovative receiver architecture. This paper introduces a complete digital implementation of a transceiver forTM/TCapplication in low Earth orbit mission that is perfectly compliant with aforementioned requirements. Particular attention is dedicated to the definition and selection of the most appropriate frequency recovery technique; 2 open-loop techniques that are derived fromMLoptimal estimator are presented and compared.Additionally, the performance of the proposed receiver is extensively studied and compared with an incoherent technique that is based on the double differential PSK modulation and is known to be suitable for sat-com in critical scenarios.