Digital Signal Process

Callisto has undertaken a number of consultancy support tasks for ESA involving Digital Signal Processing (DSP) and Ground Station Baseband Equipment. Following is a brief description of some of the projects we have supported:

Intermediate Frequency and Modem System (IFMS)

The Intermediate Frequency and Modem System (IFMS) is Telemetry, Telecommand and Ranging Modem using completely digital technology. It has been developed by ESA to meet the needs of Deep Space missions and will be deployed in all ESTRACK TT&C stations. The IFMS was developed under contract by the BAE Systems Research Centre (UK). Even though the base line was to merge the traditional telemetry, telecommand and ranging functions in one crate, the system has evolved in such a way that it has become the core of the ground station back-end. The latest IFMS upgrade supports, TM decoding up to 13Mbit/s, Delta DOR (VLVI) as well as monopulse antenna tracking receiver functionalities. In the near future, it will also be able to support Turbo and convolutional punctured codes for telemetry decoding and PN ranging. Callisto has provided support to ESA to monitor the activities of the IFMS contractor since June 2002.

The main tasks involved with this support are:

• Review of technical documentation produced by the contractor.
• Preparing technical specifications and Statement of Work (SoW).
• Attending and preparing tests campaigns both at ESOC and BAE.
• IFMS configuration and support for different ESA missions.

Monopulse Antenna Tracking Receiver

After a successful study phase where a LAN based monopulse antenna tracking receiver breadboard was developed and validated, the operational version was incorporated to the IFMS. The new firmware has been developed by BAE Systems Research Centre (UK) and has been integrated inside the IFMS mainframe. Callisto has provided support to ESA to monitor the activities of the IFMS contractor since June 2002.

The main tasks involved with this support are:

• Responsible for technical aspects of the receiver.
• Preparing technical specifications and SoW.
• Review of technical documentation produced by the contractor.
• Attending and preparing tests campaigns both at ESOC and BSATC premises.
• Responsibility for the integration in Maspalomas ESTRACK antenna.

Telemetry Channel and Decoding System (TCDS)

The initial objective of the project was to design and develop a Telemetry Channel Decoding System as a replacement for the former decoder unit (CDS2A). That new device was developed by BAE Systems Research Centre (UK) and was integrated inside the IFMS mainframe. The replacement was flexible enough to accommodate a number of anticipated channel coding functions without redesigning the initial implementation. The decoder evolved first to support higher bit rates (up to 13.8Mbit/s) and most recently, it is being upgraded to support CCSDS Turbo codes as well as Convolutional punctured codes with rates 2/3, 3/4, 5/6 and 7/8.

The main tasks involved with this support are:

• Preparing technical specifications and SoW.
• Review of technical documentation produced by the contractor.
• Attending and preparing tests campaigns both at ESOC and BSATC premises.
• TCDS configuration and support for different ESA missions.
• Responsibility for the integration of TCDS in the ESTRACK stations.

Callisto has a dedicated DCP engineer at ESOC since 2002 which has been appointed OPS-GS representative in the CCSDS Synchronisation and coding working group.