Design of a space flight qualified data processing unit for the Loss Cone Imager including the simulation of single event transients.

摘要

The Earth's magnetosphere contains large fluxes of energetic particles that are trapped spiraling around the Earth's magnetic field lines. The Loss Cone Imager will measure the energetic particle distributions parallel to the local geomagnetic field vector in the magnetosphere as part of the Demonstration and Science Experiment Satellite. The instrument uses two sets of sensor hardware to perform this task, the Fixed Sensor Head (FSH), which gives a 180° by 10° view of the sky to measure the energy of energetic electrons with a 10° by 10° resolution, and the High Sensitivity Telescope (HST), which has a 7° cutoff angle that allows the HST to view only the Loss Cone.;The Data Processing Unit (DPU) extracts and categorizes data from energetic particles received by the sensor electronics. The DPU hardware will withstand a radiation environment, avoiding errors requiring hard resets, and single event upsets caused by charged particles. I used an Actel FPGA and Aeroflex 16-bit microcontroller in the design of the DPU. Event rates of up to about one megahertz must be recorded and output as part of a 1280-byte data packet every half second.;As part of this work on the DPU design, I studied the effects of Single Event Transients (SET) in combinational logic, as well the ability of a circuit to logically mask the effects of transients. One-hot and Hamming state machine encodings were tested. The results of this testing show that the one-hot encoding performs better at avoiding undetectable errors, and requires less logic to be implemented. Hamming state machines can require 100% to 150% more combinational logic, and have a higher percentage of possible undetectable errors, as high as 10% more than one-hot. However, Hamming state machines generally have up to 30% fewer errors overall compared to one-hot state machines. This work gives future designers an idea of what type of worst case effects can be associated with each type state machine encoding.