Radio Frequency Payload Systems
'Payload' was originally a seafaring term for revenue-producing cargo on a ship. In space terms it refers to those elements of the spacecraft specifically dedicated to producing mission data and then relaying that data back to Earth - this vital communication with ground control taking place over radio frequencies
What is Radio Frequency Payload Systems?
Microwave radio signals serve as the backbone of communication between space systems and the ground. So the 'Radio Frequency' (RF) prefix in the division title comes from the fact that payload and terminal interface to and from the ground takes place at radio frequencies. In addition, modern RF payloads and terminals nowadays include advanced functionalities such as digital signal processing and sometimes optical technologies.
Telecom satellites represent the single largest commercial satellite application currently in existence. Their radio-based systems require continuous performance development and technological improvement to maintain Europe's pre-eminence in theis field in the face of highly aggressive worldwide commercial competition.
And whether on an active or passive basis, radio signals also function as a remote sensing tool for scientific observation and environmental monitoring on space science and Earth observation missions. In addition, pace-based radio navigation signals returned back to Earth form the basis of increasingly indispensable sat-nav systems.
RF Payload Systems deals with not only the specific radio technologies, equipment - low and high power amplifiers, filters, frequency converters -and systems aboard a spacecraft tasked with delivering mission objectives, but also the supporting ground equipment and telecommunication systems through which spacecraft payloads are controlled and results communicated to mission control.
On the spacecraft side this incorporates the definition and design of scientific and remote sensing instruments operating on the radio spectrum up to microwave or millimetre-wave frequencies as well as dedicated communication payloads, such as those flown on telecom satellites.
It also includes devices capable of transmitting, receiving or utilising radio signals from current and future navigation systems – the current GPS and GLONASS satellite constellations, Europe's land-based EGNOS overlay signal and the forthcoming Galileo satellite navigation system. The accurate generation of Galileo Signal-In-Space (SIS) signals require very precise on-board equipment accuracy as well as ultra-stable atomic clocks. And ground-based Galileo reference stations have to make very accurate and stable measurements of the Galileo SIS to deliver the overall system accuracy.
In terms of the Earth-based 'ground segment', RF Payload Systems covers all aspects of telemetry, tracking and telecommand (TT&C), including signal coding and modulation and radio frequency equipment and subsystems and associated standardization aspects.
