Satellite Communications Payload Simulator for Mobile and Fixed Satellite Services

As the demand for advanced satellite telecommunication services increase, the time to market for deployment of these systems has been significantly reduced. At the same time, there has been a transition from simple transponder (¿bent pipe¿) architecture operating FM/FDMA to more complex digitally switched systems. Both FDMA and TDMA systems are in use and support both analog and digital traffic with increasing emphasis on the latter. Design and test of these newer systems requires more sophisticated tools. To meet the challenging market demand, a universal Baseband and RF/Microwave Communications Payload and System Simulator (COMPASS) that is used to reduce design cycle time, validate payload software models, streamline manufacturing test matrices and study on orbit anomalies has been built and is in operation. This system contains baseband, RF, microwave, antenna and transmission path processing components. COMPASS has the capability to interactively program and reconfigure various traffic models and to load transponder channels for analysis of Mobile Satellite Service (MSS) and Fixed Satellite Service (FSS). This paper highlights some results of nonlinear transponder studies using multi-carrier CW and QPSK signals and describes the COMPASS system.