A system on chip based error detection and correction implementation for nanosatellites

Abstract

This thesis will focus on preventing and overcoming the effects of radiation in RAM on board the ZA cube 2 nanosatellite. The main objective is to design, implement and test an effective error detection and correction (EDAC) system for nanosatellite applications using a SoC development board. By conducting an in-depth literature review, all aspects of single-event effects are investigated, from space radiation right up to the implementation of an EDAC system. During this study, Hamming code was identified as a suitable EDAC scheme for the prevention of single-event effects. During the course of this thesis, a detailed radiation study of ZA cube 2’s space environment is conducted. This provides insight into the environment to which the satellite will be exposed to during orbit. It also provides insight which will allow accurate testing should accelerator tests with protons and heavy ions be necessary. In order to understand space radiation, a radiation study using ZA cube 2’s orbital parameters was conducted using OMERE and TRIM software. This study included earth’s radiation belts, galactic cosmic radiation, solar particle events and shielding. The results confirm that there is a need for mitigation techniques that are capable of EDAC. A detailed look at different EDAC schemes, together with a code comparison study was conducted. There are two types of error correction codes, namely error detection codes and error correction codes. For protection against radiation, nanosatellites use error correction codes like Hamming, Hadamard, Repetition, Four Dimensional Parity, Golay, BCH and Reed Solomon codes. Using detection capabilities, correction capabilities, code rate and bit overhead each EDAC scheme is evaluated and compared. This study provides the reader with a good understanding of all common EDAC schemes. The field of nanosatellites is constantly evolving and growing at a very fast speed. This creates a growing demand for more advanced and reliable EDAC systems that are capable of protecting all memory aspects of satellites. Hamming codes are extensively studied and implemented using different approaches, languages and software. After testing three variations of Hamming codes, in both Matlab and VHDL, the final and most effective version was Hamming [16, 11, 4]2. This code guarantees single error correction and double error detection. All developed Hamming codes are suited for FPGA implementation, for which they are tested thoroughly using simulation software and optimised.