Signal processing for the cluster wideband data burst mode

The Wideband Data instrument is part of the Cluster spacecraft Wave Experiment Consortium. Its primary data path is a direct connection to the spacecraft data handling system providing real time downlink to the ground stations of the Deep Space Network and Panska Ves Observatory. However, it was recognized during the mission design phase that this link may not always be available, especially given that simultaneous data acquisition from the four Cluster spacecraft required the use of four ground stations. Therefore, a secondary data path at reduced bit rate was included whereby the data was transferred to the Digital Wave Processor instrument and then to the spacecraft Solid State Recorder. Given that available resources were limited, both for onboard hardware and within the spacecraft assembly, integration and testing program, the design of this backup data path was less than optimal. Although it was verified during ground testing that data could be acquired via this route, the design did not make the best use of the available telemetry bandwidth, and the timing accuracy was too limited to support some multi-spacecraft observations. This paper describes work around solutions to optimize bandwidth utilization and timing accuracy. These involve patches to the onboard software of the Digital Wave Processor instrument and ingenious signal processing on the ground.