CORD - Commodity GPS Receiver Development
An analysis of the available information on future missions indicates that the SWARM GPS receiver developed by RSA has several peculiarities compared to more standard requirements of typical GPS POD receivers.
The main changes that have been identified are required for the telecommand/telemetry interface and for the satellite power bus interface. The need for MIL-STD-1553B was anticipated by RSA. As a consequence RSA has developed hardware and software required for establishing a MIL-STD-1553B interface within the frame of the ASAP 5 study Embedded Command & Control Subsystem (ECCS).
However, the remaining delta developments indispensable for converting the SWARM GPS receiver into a receiver suitable for upcoming missions are still significant. The present activity allows RSA to take this important step on the way to a commodity receiver, which can be adapted to the requirements of future missions more easily.
In particular, generic GPS POD requirements have been determined. A DC/DC converter compatible with the standard power bus of low earth orbit satellites has been designed and successfully bread-boarded taking into account small differences in switch on/off commanding and ability to deliver increased power levels for future applications demanding somewhat higher power. Last but not least the processor hardware and software has been adapted to accommodate the typical MIL-STD-1553B command and control interface with emphasis on specification and implementation of the protocol of a general purpose packet utilisation standard.
The present activity is carried out in the frame of an international co-operation with RUAG Space AB (Sweden), an independent equipment supplier with focus on electronics products particularly experienced in the area of GPS receiver and antenna development. RSE, our valuable partner in almost all GNSS- related activities, contributes its antenna experience to the study and has optimised the antenna for multipath reduction. This antenna optimisation allows accommodating the antenna on different satellite platforms.
RUAG Space GmbH - Georg Grabmayr
RUAG Space AB, Göteborg, Sweden