The satellite avionics platform has been developed in cooperation with Airbus and is called „Future Low-cost Platform“ (FLP). It is based on an Onboard Computer (OBC) with redundant processor boards based on SPARC V8 microchips of type Cobham Aeroflex UT699. At the University of Stuttgart a test bench with a real hardware OBC and a fully simulated satellite is available for testing real flight scenarios with the Onboard Software (OBSW) running on representative hardware. The test bench as later the real flying satellite "Flying Laptop" – is commanded from a real Ground Control Centre (GCC). The main challenges in the FLP project were - Onboard computer design, - Software design and - Interfaces between platform and payloads In the course of industrialization of this FLP platform technology for later use in satellite constellations, Airbus has started to set up an in-house test bench where all the technologies shall be developed. The initial plan is to get first core elements of the FLP OBSW ported to the new dual-core processor and the new Space Wire(SpW) routing network. The plan also has an inclusion of new Mission Control Software with which one can command the OBC. The new OBC has a dual core processor Cobham Gaisler GR712 and hence, all the payload and related functionality are to be implemented only in a second core which involves a lot of low-level task distribution. The consequent SpW router network application and dual-core platform/payload OBSW sharing are entirely new in the field of satellite engineering.

The aim for this thesis is to design a software library responsible for preventing, detecting, handling and logging faults caused by radiation in a representable flight computer system based on the Cobham Gaisler GR740 quad-core LEON4FT processor chip. The LEON processor family is commonly used in space applications and it is based on the open SPARC instruction set and has been extended with fault tolerant features to cope with both on-chip radiation effects as well as upsets in external memory. The new GR740 device introduces a new computer architecture with multiple buses as compared to previous chips, Level-2 cache and a memory scrubber accelerating fault mitigation in external SDRAM memories. As the processor system design keeps getting more complex it also requires software to handle more hardware and new events, including central handling and logging routines of faults. The report describes the analysis performed to identify sources of faults and proposed suitable mitigation techniques, the established software requirements and how they are translated into a software architecture, then implemented and finally demonstrated on hardware. Along with this, it is shown how the developed demonstrator application software library can be integrated into the RTEMS real-time operating system commonly used in European space missions. The results are based on the demonstrator execution, and the results show that the software is functionally working and validates that the performance of the scrubber matches the derived scrubbing timings. After the project is completed, the software library design will be evaluated for use in Cobham Gaisler’s payload computer platform for the GOMX-5 mission. Radiation upsets will be emulated by injecting faults while running the developed API on demonstrator applications. Furthermore, implementation of software into NASA cFS/cFE will be analysed.

The satellite avionics platform has been developed in cooperation with Airbus and is called „Future Low-cost Platform“ (FLP). It is based on an Onboard Computer (OBC) with redundant processor boards based on SPARC V8 microchips of type Cobham Aeroflex UT699. At the University of Stuttgart a test bench with a real hardware OBC and a fully simulated satellite is available for testing real flight scenarios with the Onboard Software (OBSW) running on representative hardware. The test bench as later the real flying satellite "Flying Laptop" – is commanded from a real Ground Control Centre (GCC). The main challenges in the FLP project were - Onboard computer design, - Software design and - Interfaces between platform and payloads In the course of industrialization of this FLP platform technology for later use in satellite constellations, Airbus has started to set up an in-house test bench where all the technologies shall be developed. The initial plan is to get first core elements of the FLP OBSW ported to the new dual-core processor and the new Space Wire(SpW) routing network. The plan also has an inclusion of new Mission Control Software with which one can command the OBC. The new OBC has a dual core processor Cobham Gaisler GR712 and hence, all the payload and related functionality are to be implemented only in a second core which involves a lot of low-level task distribution. The consequent SpW router network application and dual-core platform/payload OBSW sharing are entirely new in the field of satellite engineering.

O Sistema de Posicionamento Global (GPS) permite uma grande variedade de aplicações civis e militares. Dentre as várias aplicações, uma de especial interesse é a navegação, que tem crescido muito nos últimos anos devido a fatores como menor custo, e fácil utilização desta tecnologia. Num sistema de navegação terrestre, assim como na navegação marítima, fluvial e aérea, um mapa digitalizado, ou imagem de satélite disponível da região de interesse é exibida na tela do computador de bordo e a posição do veículo é apresentada em "tempo real" a partir da posição fornecida por receptores GPS. Além disso, a comunicação disponível nos dias de hoje permite uma maior integração entre o veículo e o escritório. Finalmente, o Google Earth permite que se tenha acesso a uma grande quantidade de informações necessárias ao desenvolvimento de inúmeros trabalhos, permitindo inclusive a inserção de fotos e imagens para registro dos acontecimentos. O potencial deste tipo de sistema só foi possível a partir de maio de 2000, com a eliminação da SA (Selective Availability).Com isso, o posicionamento absoluto realizado por receptores de navegação (menos precisos do que os receptores geodésicos) foi aprimorado, podendo conseguir precisões da ordem de 10m, o que aumenta a qualidade de aplicações como a navegação terrestre. A proposta desta dissertação é descrever o desenvolvimento de um protótipo veicular para aplicações de campo em Geociências, onde foi incluída a navegação em tempo real, o uso da internet para a comunicação pessoal e interface de acesso ao Google Earth. O protótipo desenvolvido permite a extensão de parte da infra-estrutura de um laboratório para apoio das atividades de campo. / In our days the Global Positioning Systems (GPS) is a technology with a great variety of military and civilian applicability. Among this uses, navigation is one activity that is largely increasing in reason to lowering equipment prices and introduced facilities as easy to use technology. In practice, a system structured to navigate in terrestrial, maritime, fluvial or aerial way is formed by a GPS connected to an onboard computer and video equipped with appropriate software that process in a instantaneous mode (real time) all the information necessary to show on screen the geographical position of the vehicle. In parallel, new advances in network communication open the possibility to integrate completely the vehicle in movement with the staff in the office. Also, the Geoogle Earth™ and World Wide Web increase the facilities to view online the terrain and open the possibility to user interact directly with routines that insert local photo and images. Navigate with accuracy using a single-receiver GPS linked to a computer was only possibly after May of 2000, when the SA (Selective Availability) was excluded from GPS signal. Consequently, absolute positioning with one band handled GPS (low accuracy when compared to geodetic two bands GPS) was tested and the results show the availability to locate points in the Earth surface with an uncertainty degree not above than 10 meters (in terms of planimmetric coordinates). This performance increases the data quality and the ability of single-receiver GPS to be used to navigation purposes. In this work, it is assembled and tested a navigation system prototype installed in a vehicle with the objective to optimize field survey and adapted to some geosciences necessities, including the possibility to navigate in real time integrated with Internet facilities to personal communication and with an interface to access the Google Earth™. The configuration of the navigation system prototype elaborated in this project permit to extend to the field some facilities only accessible in a laboratory environment and consequently the results obtained with the system increased the performance of all the field work stages.

O Sistema de Posicionamento Global (GPS) permite uma grande variedade de aplicações civis e militares. Dentre as várias aplicações, uma de especial interesse é a navegação, que tem crescido muito nos últimos anos devido a fatores como menor custo, e fácil utilização desta tecnologia. Num sistema de navegação terrestre, assim como na navegação marítima, fluvial e aérea, um mapa digitalizado, ou imagem de satélite disponível da região de interesse é exibida na tela do computador de bordo e a posição do veículo é apresentada em "tempo real" a partir da posição fornecida por receptores GPS. Além disso, a comunicação disponível nos dias de hoje permite uma maior integração entre o veículo e o escritório. Finalmente, o Google Earth permite que se tenha acesso a uma grande quantidade de informações necessárias ao desenvolvimento de inúmeros trabalhos, permitindo inclusive a inserção de fotos e imagens para registro dos acontecimentos. O potencial deste tipo de sistema só foi possível a partir de maio de 2000, com a eliminação da SA (Selective Availability).Com isso, o posicionamento absoluto realizado por receptores de navegação (menos precisos do que os receptores geodésicos) foi aprimorado, podendo conseguir precisões da ordem de 10m, o que aumenta a qualidade de aplicações como a navegação terrestre. A proposta desta dissertação é descrever o desenvolvimento de um protótipo veicular para aplicações de campo em Geociências, onde foi incluída a navegação em tempo real, o uso da internet para a comunicação pessoal e interface de acesso ao Google Earth. O protótipo desenvolvido permite a extensão de parte da infra-estrutura de um laboratório para apoio das atividades de campo. / In our days the Global Positioning Systems (GPS) is a technology with a great variety of military and civilian applicability. Among this uses, navigation is one activity that is largely increasing in reason to lowering equipment prices and introduced facilities as easy to use technology. In practice, a system structured to navigate in terrestrial, maritime, fluvial or aerial way is formed by a GPS connected to an onboard computer and video equipped with appropriate software that process in a instantaneous mode (real time) all the information necessary to show on screen the geographical position of the vehicle. In parallel, new advances in network communication open the possibility to integrate completely the vehicle in movement with the staff in the office. Also, the Geoogle Earth™ and World Wide Web increase the facilities to view online the terrain and open the possibility to user interact directly with routines that insert local photo and images. Navigate with accuracy using a single-receiver GPS linked to a computer was only possibly after May of 2000, when the SA (Selective Availability) was excluded from GPS signal. Consequently, absolute positioning with one band handled GPS (low accuracy when compared to geodetic two bands GPS) was tested and the results show the availability to locate points in the Earth surface with an uncertainty degree not above than 10 meters (in terms of planimmetric coordinates). This performance increases the data quality and the ability of single-receiver GPS to be used to navigation purposes. In this work, it is assembled and tested a navigation system prototype installed in a vehicle with the objective to optimize field survey and adapted to some geosciences necessities, including the possibility to navigate in real time integrated with Internet facilities to personal communication and with an interface to access the Google Earth™. The configuration of the navigation system prototype elaborated in this project permit to extend to the field some facilities only accessible in a laboratory environment and consequently the results obtained with the system increased the performance of all the field work stages.

O Sistema de Posicionamento Global (GPS) permite uma grande variedade de aplicações civis e militares. Dentre as várias aplicações, uma de especial interesse é a navegação, que tem crescido muito nos últimos anos devido a fatores como menor custo, e fácil utilização desta tecnologia. Num sistema de navegação terrestre, assim como na navegação marítima, fluvial e aérea, um mapa digitalizado, ou imagem de satélite disponível da região de interesse é exibida na tela do computador de bordo e a posição do veículo é apresentada em "tempo real" a partir da posição fornecida por receptores GPS. Além disso, a comunicação disponível nos dias de hoje permite uma maior integração entre o veículo e o escritório. Finalmente, o Google Earth permite que se tenha acesso a uma grande quantidade de informações necessárias ao desenvolvimento de inúmeros trabalhos, permitindo inclusive a inserção de fotos e imagens para registro dos acontecimentos. O potencial deste tipo de sistema só foi possível a partir de maio de 2000, com a eliminação da SA (Selective Availability).Com isso, o posicionamento absoluto realizado por receptores de navegação (menos precisos do que os receptores geodésicos) foi aprimorado, podendo conseguir precisões da ordem de 10m, o que aumenta a qualidade de aplicações como a navegação terrestre. A proposta desta dissertação é descrever o desenvolvimento de um protótipo veicular para aplicações de campo em Geociências, onde foi incluída a navegação em tempo real, o uso da internet para a comunicação pessoal e interface de acesso ao Google Earth. O protótipo desenvolvido permite a extensão de parte da infra-estrutura de um laboratório para apoio das atividades de campo. / In our days the Global Positioning Systems (GPS) is a technology with a great variety of military and civilian applicability. Among this uses, navigation is one activity that is largely increasing in reason to lowering equipment prices and introduced facilities as easy to use technology. In practice, a system structured to navigate in terrestrial, maritime, fluvial or aerial way is formed by a GPS connected to an onboard computer and video equipped with appropriate software that process in a instantaneous mode (real time) all the information necessary to show on screen the geographical position of the vehicle. In parallel, new advances in network communication open the possibility to integrate completely the vehicle in movement with the staff in the office. Also, the Geoogle Earth™ and World Wide Web increase the facilities to view online the terrain and open the possibility to user interact directly with routines that insert local photo and images. Navigate with accuracy using a single-receiver GPS linked to a computer was only possibly after May of 2000, when the SA (Selective Availability) was excluded from GPS signal. Consequently, absolute positioning with one band handled GPS (low accuracy when compared to geodetic two bands GPS) was tested and the results show the availability to locate points in the Earth surface with an uncertainty degree not above than 10 meters (in terms of planimmetric coordinates). This performance increases the data quality and the ability of single-receiver GPS to be used to navigation purposes. In this work, it is assembled and tested a navigation system prototype installed in a vehicle with the objective to optimize field survey and adapted to some geosciences necessities, including the possibility to navigate in real time integrated with Internet facilities to personal communication and with an interface to access the Google Earth™. The configuration of the navigation system prototype elaborated in this project permit to extend to the field some facilities only accessible in a laboratory environment and consequently the results obtained with the system increased the performance of all the field work stages.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The Electronic Systems Laboratory at Stellenbosch University is currently developing a fully 3-axis controlled Attitude Determination and Control Subsystem (ADCS) for CubeSats. This thesis describes the design and development of an Onboard Computer (OBC) suitable for ADCS application. A separate dedicated OBC for ADCS purposes allows the main CubeSat OBC to focus only on command and data handling, communication and payload management. This thesis describes, in detail the development process of the OBC. Multiple Microcontroller Unit (MCU) architectures were considered before selecting an ARM Cortex-M3 processor due to its performance, power efficiency and functionality. The hardware was designed to be as robust as possible, because radiation tolerant and redundant components could not be included, due to their high cost and the technical constraints of a CubeSat. The software was developed to improve recovery from lockouts or component failures and to enable the operational modes to be configured in real-time or uploaded from the ground station. Ground tests indicated that the OBC can handle radiation-related problems such as latchups and bit-flips. The peak power consumption is around 500 mW and the orbital average is substantially lower. The proposed OBC is therefore not only sufficient in its intended application as an ADCS OBC, but could also stand in as a backup for the main OBC in case of an emergency. / AFRIKAANSE OPSOMMING: Die Elektroniese Stelsels Laboratorium by die Universiteit van Stellenbosch is tans besig om ’n volkome 3-as gestabiliseerde oriëntasiebepaling en -beheerstelsel (Engels: ADCS) vir ’n CubeSat te ontwikkel. Hierdie tesis beskryf die ontwerp en ontwikkeling van ’n aanboordrekenaar (Engels: OBC) wat gebruik kan word in ’n ADCS. ’n Afsonderlike OBC wat aan die ADCS toegewy is, stel die hoof-OBC in staat om te fokus op beheer- en datahantering, kommunikasie en loonvragbestuur. Hierdie tesis beskryf breedvoerig die werkswyse waarvolgens die OBC ontwikkel is. Verskeie mikroverwerkers is as moontlike kandidate ondersoek voor daar op ’n ARM Cortex-M3-gebaseerde mikroverwerker besluit is. Hierdie mikroverwerker is gekies vanweë sy spoed, effektiewe kragverbruik en funksionaliteit. Die hardeware is ontwikkel om so robuust moontlik te wees, omdat stralingbestande en oortollige komponente weens kostebeperkings, asook tegniese beperkings van ’n CubeSat, nie ingesluit kon word nie. Die programmatuur is ontwikkel om van ’n uitsluiting en ’n komponentfout te kan herstel. Verder kan programme wat tydens vlug in werking is, verstel word en vanaf ’n grondstasie gelaai word. Grondtoetse het aangedui dat die OBC stralingverwante probleme, soos ’n vergrendeling (latchup) of bis-omkering (bit-flip), kan hanteer. Die maksimum kragverbruik is ongeveer 500 mW en die gemiddelde wentelbaankragverbruik is beduidend kleiner. Die voorgestelde OBC is dus voldoende as ADCS OBC asook hoof-OBC in geval van nood.