Data Processing Units for Eight Magnetospheric Particle and Field Sensors

The DPUA, DPUB, and DPU57 data processing units associated with eight CRRES particle and field experiments are described. Operation of the experiments is controlled by the data processing units DPUs, which constitute the interface between the spacecraft and the sensors subserving the individual experiments. All data to and from the sensors pass through the associated DPUs. Each DPU consists of a microprocessor, power supply, signal handler, and various peripherals such as inputoutput buffers and specialized data processing hardware. In addition to experiment control and data processing functions, DPU software performs such tasks as loading the system software from ROM into RAM, writing the memory-resident look-up tables utilized by the DPU hardware, checking the system RAMs for memory retention faults, outputting system memory to the telemetry stream, and outputting a fixed pattern of telemetry. To maximize the available telemetry bandwidth, much of the raw sensor data is analyzed by the DPUs, using various onboard processing schemes, and then compressed prior to being output in telemetry. Magnetosphere.