Satellite Communications Payload and System

Chapter 1

Introduction

1.1 What This Book Is About

This book is about the payload of communications satellites. The payload is what the satellite is for, namely the payload is what performs the functions desired of the satellite. In a nutshell, the payload is the communications antennas, receivers, and transmitters. The rest of the satellite, the bus, supports the payload by providing a structure, power, commanding, and telemetry, an appropriate thermal environment, radiation shielding, and attitude control.

The book has two parts, the first part having to do with the payload itself and as part of the satellite and the second part having to do with the payload as part of the end-to-end satellite communications system. Typically, the end-to-end system consists of a transmitter on the ground, the payload on orbit, and a receiver on the ground, as shown in Figure 1.1; this is what we will generally refer to. However, an end-to-end system could have another satellite as originating transmitter and/or as destination receiver, and virtually all of this book would still apply in this case; however, such a system has additional considerations which are not dealt with here.

Figure 1.1 End-to-end satellite communications system, transmitter on ground through receiver on ground.

The payload typically has on the order of a hundred pages of customer requirements. Analysis of these requirements ...