Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: A new task scheduler for the Attitude Determination and Control System (ADCS) of the Stellenbosch University Satellite (SUNSAT) has been designed and tested on a personal computer. This new scheduler is capable of uploading new control tasks, or changing existing control tasks, on an individual basis. This is an improvement on the current ADCS task scheduler, where the control tasks are hard-coded in the scheduler, requiring the entire software image of the scheduler to be uploaded if a new task is to be added, or an existing task is to be changed. The new scheduler was developed using the Java programming language. The Java ClassLoader class is used to dynamically load tasks to a linked list. The scheduler thread runs through this linked list and schedules all the tasks that have become schedulable. New tasks can be added to the list without stopping the scheduler. The new scheduler has been successfully implemented on a personal computer, laying a good foundation for implementation in an embedded environment based on processors such as the T800 Transputer of the ADCS or the 80386 processor of the secondary onboard computer (OBC2). / AFRIKAANSE OPSOMMING: 'n Nuwe taak skeduleerder vir die orientasie beheerstelsel (Engels: Attitude Determination and Control System, of ADCS) van die Stellenbosch Universiteit Satelliet (SUNSAT) is ontwerp en getoets op 'n persoonlike rekenaar. Hierdie nuwe skeduleerder het die verrnoee om ekstra beheertake op te laai, of bestaande beheertake te wysig, onafhanklik van mekaar. Dit is 'n verbetering op die huidige ADCS taak skeduleerder waar take hard gekodeer is in die skeduleerder en waar vereis word dat die volledige sagteware beeld van die skeduleerder opgelaai moet word indien 'n nuwe taak bygevoeg wil word of 'n bestaande taak gewysig wil word. Die nuwe skeduleerder is ontwikkel met behulp van die Java programmeringstaal. Die Java C/assLoader klas is gebruik om take dinamies te laai en te voeg by 'n skakellys. Die skeduleerder proses stap dan deur hierdie skakellys en skeduleer aile take wat skeduleerbaar geword het. Nuwe take kan by die skakellys gevoeg word sonder om die skeduleerder te stop. Die nuwe skeduleerder is suksesvol ge'lmplementeer op 'n persoonlike rekenaar en Ie 'n goeie grondslag vir implementering in 'n toegewyde stelsel omgewing gebaseer op byvoorbeeld die T800 Transputer van die ADCS of die 80386 verwerker van die sekondere aanboord rekenaar (OBC2).

Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: For space designs, just as for terrestrial applications, the appetite for more computing power is virtually insatiable. Further, like portable applications, space use implies severe power constraints. Among currently available commercial processors, the PowerPC family ranks high in Million Instructions Per Second (MIPS) per watt, but its suitability for space applications outside low-earth orbits (LEOs) may be limited by the radiation environment, particularly single ev nt effects (SEE). This thesis covers the feasibility of using the PowerPC 603e™ processor for LEO satellite applications. The PowerPC architecture is well established with an excellent roadmap, which makes for a baseline microprocessor with long-term availability and excellent software support. The evaluation board design leverages Commercial Off-The-Shelf (COTS) technologies, allowing early integration and test. It provides a clear path to upgrades and provides a high performance platform to suit multiple missions. / AFRIKAANSE OPSOMMING: Die soeke na rekenaars met hoer werkverrigting sal nooit ophou rue. Dit geld vir beide rekenaars op aarde as satelliet aanboord rekenaars. Rekenaars vir ruimte gebruik word ook streng drywingsbeperkings opgele. Die PowerPC familie vergelyk baie goed met ander verwerkers, maar hul bruikbaarheid vir ruimte toepassings kan dalk beperk word tot lae wentelbane waar die ruimte radiasie omgewing meer toeganklik is. Die skrywe behandel die bruikbaarheid van die PowerPC 603e verwerker vir lae wentelbaan satelliet gebruik. Die welgestelde argitektuur, bekombaarheid en uitstekende sagte- _ ware ondersteuning verseker 'n standvastige fondasie. Kornmersiele komponente het voorkeur geniet in die hardeware ontwerp wat spoedige ontwikkeling sowel as aanpasbaarheid verseker. Die ontwerp bied 'n hoe werkverrigting en maklik opgradeerbare oplossing vir 'n groot verskeidenheid gebruike.

Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The use of commercial-off-the-shelf (COTS) components and emerging technologies in satellite systems has become increasingly popular over the past few years. This is mainly due to advances in radiation shielding and system-level reliability improving techniques. The use of a new generation commercial processor in the design of a satellite's on-board computer (OBC) is now considered a feasible option. The aim of this thesis was to evaluate the use of a commercial grade ARM processor in a low earth orbit (LEO) microsatellite on-board computer. The process began with the selection of the most suitable ARM processor for an aBC design. A typical aBC system was developed for the chosen processor, in order to test its functionality and performance in anOBC design. / AFRIKAANSE OPSOMMING: Die afgelope paar jaar het die gebruik van gewone kommersiële komponente en die nuutste tegnologie in satelliet stelsels heelwat toegeneem. Dit kan grootliks toeskryf word aan die vordering in bestralings afskerming en stelselvlak betroubaarheid tegnieke. Die gebruik van 'n nuwe generasie kommersiële verwerker in die ontwerp van 'n satellite aanboord rekenaar (AR) is nou prakties uitvoerbaar. Die doel van hierdie tesis was om die gebruik van 'n ARM verwerker in 'n lae aardwentelbaan mikrosatelliet aanboord rekenaar te evalueer. Eerstens moes die mees geskikte kommersiële ARM verwerker vir 'n AR ontwerp gevind word. Daarna is 'n tipiese AR stelselontwikkel om die verwerker se funksionaliteit en werkverrigting te toets.

Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The aim of this thesis is to investigate the implementation of a high-speed serial bus based on the IEEE Std 1394-1995 specification for use in a microsatellite. Earth observation microsatellites carry imagers (or cameras) that take photographs of the earth. Each photograph generates a large volume of digital data that has to be transferred to either a storage device, a RF transmission unit or a video processing device. Traditionally, the connection between such systems were dedicated serial bus systems that were custom designed for just that purpose. This thesis will investigate the the implementation of a generic alternative to such a custom serial bus. The IEEE 1394 serial bus will allow many devices and subsystems to be connected to the serial bus and will allow these different subsystems to exchange data between each other. As an example implementation, a real-time video link between two points using the IEEE 1394 serial bus will be developed. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om ondersoek in te stel na die bou van 'n hoëspoed seriebus vir gebruik in 'n mikrosatelliet gebaseer is op die IEEE Std 1394-1995 spesifikasie. Aardobservasie-mikrosatelliete bevat kameras wat fotos van die aarde neem. Elke foto genereer groot volumes digitale data wat na óf 'n massastoor, óf 'n RF-sender, óf 'n video-verwerkingseenheid gestuur word. Tradisioneel is elkeen van hierdie verbindings met 'n toegewyde seriebus gedoen wat spesiaal vir daardie doel gemaak is. Hierdie tesis het dit ten doelom ondersoek in te stel na 'n generiese alternatief vir hierdie toegewyde seriële busse. Die IEEE 1394 seriebus sal toelaat dat verskeie eenhede en substelsels aan mekaar gekoppel kan word en dat hulle data tussen mekaar kan uitruil. Ter demonstrasie sal 'n intydse videoskakel ontwerp word wat die IEEE 1394 seriebus gebruik om data tussen twee punte oor te dra.

Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The Linux operating system and shared Ethernet are alternative technologies with the potential to reduce both the development time and costs of satellites as well as the supporting infrastructure. Modular satellites, ground stations and rapid proto typing testbeds also have a common requirement for distributed real-time computation. The identified technologies were investigated to determine whether this requirement could also be met. Various real-time extensions and modifications are currently available for the Linux operating system. A suitable open source real-time extension called Real-Time Application Interface (RTAI) was selected for the implementation of an experimental distributed real-time system. Experimental results showed that the RTAI operating system could deliver deterministic realtime performance, but only in the absence of non-real-time load. Shared Ethernet is currently the most popular and widely used commercial networking technology. However, Ethernet wasn't developed to provide real-time performance. Several methods have been proposed in literature to modify Ethernet for real-time communications. A token passing protocol was found to be an effective and least intrusive solution. The Real-Time Token (RTToken) protocol was designed to guarantee predictable network access to communicating real-time tasks. The protocol passes a token between nodes in a predetermined order and nodes are assigned fixed token holding times. Experimental results proved that the protocol offered predictable network access with bounded jitter. An experimental distributed real-time system was implemented, which included the extension of the RTAI operating system with the RTToken protocol, as a loadable kernel module. Real-time tasks communicated using connectionless Internet protocols. The Real-Time networking (RTnet) subsystem of RTAI supported these protocols. Under collision-free conditions consistent transmission delays with bounded jitter was measured. The integrated RTToken protocol provided guaranteed and bounded network access to communicating real-time tasks, with limit overheads. Tests exhibited errors in some of the RTAI functionality. Overall the investigated technologies showed promise in being able to meet the distributed real-time requirements of various applications, including those found in the satellite environment. / AFRIKAANSE OPSOMMING: Die Linux bedryfstelsel en gedeelde Ethernet is geïdentifiseer as potensiële tegnologieë vir satelliet bedryf wat besparings in koste en vinniger ontwikkeling te weeg kan bring. Modulêr ontwerpte satelliete, grondstasies en ontwikkeling platforms het 'n gemeenskaplike behoefte vir verspreide intydse verwerking. Verskillende tegnologieë is ondersoek om te bepaal of aan die vereiste ook voldoen kan word. Verskeie intydse uitbreidings en modifikasies is huidiglik beskikbaar vir die Linux bedryfstelsel. Die "Real-Time Application Interface" (RTAI) bedryfstelsel is geïdentifiseer as 'n geskikte intydse uitbreiding vir die implementering van 'n eksperimentele verspreide intydse stelsel. Eksperimentele resultate het getoon dat die RTAI bedryfstelsel deterministies en intyds kan opereer, maar dan moet dit geskied in die afwesigheid van 'n nie-intydse verwerkingslas. Gedeelde Ethernet is 'n kommersiële network tegnologie wat tans algemeen beskikbaar is. Die tegnologie is egter nie ontwerp vir intydse uitvoering nie. Verskeie metodes is in die literatuur voorgestelom Ethernet te modifiseer vir intydse kommunikasie. Hierdie ondersoek het getoon dat 'n teken-aangee protokol die mees effektiewe oplossing is en waarvan die implementering min inbreuk maak. Die "Real-Time Token" (RTToken) protokol is ontwerp om voorspelbare netwerk toegang tot kommunikerende intydse take te verseker. Die protokol stuur 'n teken tussen nodusse in 'n voorafbepaalde volgorde. Nodusse word ook vaste teken hou-tye geallokeer. Eksperimentele resultate het aangedui dat die protokol deterministiese netwerk toegang kan verseker met begrensde variasies. 'n Eksperimentele verspreide intydse stelsel is geïmplementeer. Dit het ingesluit die uitbreiding van die RTAI bedryfstelsel met die RTToken protokol; verpak as 'n laaibare bedryfstelsel module. Intydse take kan kommunikeer met verbindinglose protokolle wat deur die "Real-Time networking" (RTnet) substelsel van RTAI ondersteun word. Onder ideale toestande is konstante transmissie vertragings met begrensde variasies gemeet. Die integrasie van die RTToken protokol het botsinglose netwerk toegang aan kommunikerende take verseker, met beperkte oorhoofse koste as teenprestasie. Eksperimente het enkele foute in die funksionaliteit van RTAI uitgewys. In die algemeen het die voorgestelde tegnologieë getoon dat dit potensiaal het vir verskeie verspreide intydse toepassings in toekomstige satelliet en ook ander omgewings.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Keywords: digital signal processing, embedded systems, telecommunications, satellite technology. The rapid growth of the telecommunications industry is a worldwide phenomenon with people and computers generating and transmitting more and more information daily. Despite this growth, there are still areas in South Africa which lack terrestrial communications coverage. People inhabit these rural areas and their essential communication needs are not met. Satellite based communication coverage can provide a valuable service in these circumstances. In this thesis, the design of a satellite-based communications payload which makes use of software de ned radio techniques is presented in terms of the Open Systems Interconnect layer structure. A robust hardware platform using a space-quali ed on-board computer, a Xilinx Virtex-5 Field Programmable Gate Array (FPGA) and a Freescale digital signal processor (DSP) is designed, implemented and thoroughly tested. A device driver is designed for hardware and rmware components. A prototype ground station is also designed and constructed using a low-power PC, a Xilinx Spartan-3E FPGA, a Freescale DSP and radio frequency hardware. A wide range of testing methodologies were successfully utilised to deploy a functional system which is critically evaluated in the last chapter. / AFRIKAANSE OPSOMMING: Sleutelwoorde: syferseinverwerking, toegewyde stelsels, telekommunikasie, satelliettegnologie. Die vinnig groeiende telekommunikasieindustrie is 'n wêreldwye verskynsel waarin mense en rekenaars daagliks meer en meer data genereer. Ten spyte van die groei, is daar nog steeds gebiede in Suid-Afrika wat aan 'n gebrek van aardse kommunikasiedekking lei. Mense bewoon dié areas maar daar word nie aan hul noodsaaklike kommunikasiebehoeftes voldoen nie. Satelliet-gebaseerde kommunikasiedekking kan 'n waardevolle diens in hierdie omstandighede wees. Hierdie tesis beskryf die ontwerp van 'n ruimtegebaseerde kommunikasieloonvrag wat gebruik maak van sagteware-gede nieerde radiotegnieke aangebied in terme van die Open Systems Interconnect laagstruktuur. 'n Robuuste apparatuurplatform wat gebruik maak van 'n ruimte-gekwali seerde rekenaar, 'n Xilinx Virtex-5 Veldprogrameerbare Hek-Skikking (VPHS) en 'n Freescale syferseinverwerker is ontwerp, geïmplementeer en deeglik getoets. 'n Toestelbestuurder moes ontwerp word vir die apparatuur- en fermatuur-komponente. 'n Prototipe grondstasie is ook ontwerp en gebou met behulp van' n lae-krag PC, 'n Xilinx Spartan-3E VPHS, 'n Freescale seinverwerker en radiofrekwensie apparatuur. 'n Wye verskeidenheid van toetsmetodes is suksesvol benut om 'n funksionele stelsel te ontwikkel wat krities geëvalueer word in die laaste hoofstuk.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In this thesis the design and testing of the baseband components of a modem intended for use as a telemetry and control link for a low earth orbit satellite is presented. This includes parts of the physical layer as well as a basic data-link layer. Binary phase-shift keying (BPSK) is used as the modulation scheme and is realised by making use of software defined radio on a standard x86 computer with digital to analogue and analogue to digital converters that use a universal serial bus (USB) connection. The data-link layer makes use of a basic framing scheme and provides bit synchronisation, an automatic repeat request (ARQ) system and Bose Chaudhuri Hocquenghem (BCH) forward error correction (FEC). The ARQ system ensures that data is delivered reliably and the FEC improves the system’s performance in noisy conditions. A prototype system was developed to test the performance of the individual layers as well as the system as a whole. For testing purposes the Linux Internet Protocol (IP) stack is used as higher network layers. Radio frequency hardware developed by Verschaeve [1] modulates the signal away from baseband, transmits it over the air and receives it. / AFRIKAANSE OPSOMMING: In hierdie tesis word die ontwerp en toetsing van die basisband komponente van ‘n modem, bedoel vir gebruik op ‘n satelliet in ‘n lae-aarde wentelbaan, bespreek. Die ontwerp sluit dele van die fisiese vlak sowel as ‘n verbindingsvlak in. Binêre faseskuifsleuteling word gebruik as die modulasieskema en word verwesenlik deur gebruik te maak van sagteware gedefinieerde radio. Dit voer uit op ’n standaard x86 rekenaar wat deur middel van USB gekoppel is aan ’n digitaal-na-analoog- en ’n analoog-na-digitaal-omsetter. Die verbindingsvlak het ‘n eenvoudige ramingskema. Dit voorsien bis sinkronisasie, die hersending van verlore rame en Bose Chaudhuri Hocquenghem (BCH) voorwaartse foutverbetering. Die hersending van verlore rame verseker dat data betroubaar oorgedra kan word en foutverbetering verbeter die stelsel se vermoëns in ruiserige toestande. ‘n Prototipe stelsel is ontwikkel om die vermoëns van die individuele vlakke, sowel as die stelsel as ’n geheel, te toets. Tydens toetsing is die Linux Internet Protokol stapel gebruik vir die hoër netwerk vlakke. Radio komponente wat deur Verschaeve [1] ontwikkel was is gebruik om die sein uit te saai en te ontvang.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The main on-board computer in a satellite is responsible for ensuring the correct operation of the entire system. It performs this task using flight software. In order to reduce future development costs, it is desirable to develop generic software that can be re-used on subsequent missions. This thesis details the design and implementation of a generic flight software application for CubeSats. A generic, modular framework is used in order to increase the re-usability of the flight software architecture. In order to simplify the management of the various on-board processes, the software is built upon the FreeRTOS real-time operating system. The Consultative Committee for Space Data Systems’ telemetry and telecommand packet definitions are used to interface with ground stations. In addition, a number of services defined in the European Cooperation for Space Standardisation’s Packet Utilisation Standard are used to perform the functions required from the flight software. The final application contains all the command and data handling functionality required in a standard CubeSat mission. Mechanisms for the collection, storage and transmission of housekeeping data are included as well as the implementation of basic fault tolerance techniques. Through testing it is shown that the FreeRTOS scheduler can be used to ensure the software meets hard-real time requirements. / AFRIKAANSE OPSOMMING: Die hoof aanboordrekenaar in ’n satelliet verseker die korrekte werking van die hele stelsel. Die rekenaar voer hierdie taak uit deur van vlugsagteware gebruik te maak. Om toekomstige ontwikkelingskostes te verminder, is dit noodsaaklik om generiese sagteware te ontwikkel wat hergebruik kan word op daaropvolgende missies. Hierdie tesis handel oor die besonderhede van die ontwerp en implementering van generiese vlugsagteware vir ’n CubeSat. ’n Generiese, modulêre raamwerk word gebruik om die hergebruik van die sagteware te verbeter. Ten einde die beheer van die verskillende aanboordprosesse te vereenvoudig, word die sagteware gebou op die FreeRTOS reëletyd bedryfstelsel. Die telemetrie- en telebevelpakket definisies van die “Consultative Committee for Space Data Systems” word gebruik om met grondstasies te kommunikeer. Daarby is ’n aantal dienste omskryf in die “Packet Utilisation Standard” van die “European Cooperation for Space Standardisation” gebruik om die vereiste funksies van die vlugsagteware uit te voer. Die finale sagteware bevat al die bevel en data-hantering funksies soos wat vereis word van ’n standaard CubeSat missie. Meganismes vir die versameling, bewaring en oordrag van huishoudelike data is ingesluit sowel as die implementering van basiese fouttolerante tegnieke. Toetse het gewys dat die FreeRTOS skeduleerder gebruik kan word om te verseker dat die sagteware aan harde reëletyd vereistes voldoen.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: With CubeSats becoming popular as a cheap alternative to larger satellites, the need for advanced miniature attitude determination and control systems (ADCS) arises to meet the pointing requirements of satellite operations such as earth imaging and orbit maintenance. This thesis describes the design of a complete ADCS for use on CubeSats. A previously designed CubeSat on-board-computer, CubeComputer, and ne sun and nadir sensor, CubeSense, is incorporated in the design. The remaining requirements with regard to sensors and actuators were met by CubeControl, an additional module, the design, manufacturing and testing of which are described. CubeControl can implement magnetic control with the use of a magnetometer and three magnetorquers. It is also capable of driving three reaction wheels for accurate active 3-axis stabilization. / AFRIKAANSE OPSOMMING: Met CubeSats wat gewild raak as 'n goedkoop alternatief tot groter satelliete ontstaan die behoefte vir gevorderde miniatuur ori entasiebepaling en -beheerstelsels wat satelliet operasies soos aardwaarneming en wentelbaan korreksies moontlik maak. Hierdie tesis beskryf die ontwerp van 'n volledige ori entasiebepaling en -beheerstelsel vir CubeSats. 'n Voorheen ontwikkelde CubeSat aanboordrekenaar, CubeComputer, en 'n fyn sonsensor en nadirsensor, CubeSense, is ingesluit in die ontwerp. Die orige benodighede met verband tot sensors en aktueerders word vervul deur CubeControl, 'n addisionele module waarvan die ontwerp, vervaardiging en toetsing beskyf word. CubeControl kan magnetiese beheer implementeer deur gebruik te maak van 'n magnetometer en drie magneetstange. Dit kan ook drie reaksiewiele aandryf vir akkurate aktiewe 3-as stabilisering.

Made available in DSpace on 2015-03-26T13:28:36Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1996865 bytes, checksum: 80a7a778bb6c66c23c06d757b2a4c310 (MD5) Previous issue date: 2015-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Among the technologies of spatial positioning, highlight the GNSS (Global Navigation Satellite System), which is widely used in various applications in the area of Geodesy, among others. The precise point positioning (PPP) has been shown to be a powerful tool for geodetic and geodynamics. applications Relative positioning is still the most widely used method for determination of coordinates in precision geodetic surveys. However, the PPP is increasingly in evidence and has provided satisfactory results. Given the above, remains to be seen, among the techniques mentioned, which provides more accurate results currently. The data used in this study were collected by the stations of RBMC (Brazilian Network for Continuous Monitoring of GNSS Systems) provided by IBGE (Brazilian Institute of Geography and Statistics), for the date January 01, 2014. For PPP analysis was used the free service online IBGE-PPP, and for analysis of static relative positioning was used the free online placement service AUSPOS, that processes network data, using the scientific software Bernese, and commercial software LGO (Leica Geo Office), which was used for processing single baselines and multiple baselines (vector adjustment).The GPS data were processed by varying the trace interval, covering the intervals of 1, 2, 4, 6, 8, 10 and 12 hours. In IBGE-PPP and AUSPOS the results provided was referenced to IGb08 (ITRF2008) at the time of data collection. To process the data in the LGO, the coordinates of the base stations, available in SIRGAS2000, epoch 2000.4, were transformed and updated to the reference system IGb08 (ITRF2008) at the time of data collection.Thus, the estimated coordinates at LGO were also estimated in IGb08 at the time of data collection. In sequence, the coordinates estimated in LGO, IBGE-PPP and AUSPOS were compared with the coordinates provided in descriptive of RBMC stations,which were also transformed and updated to the same reference system and time of coordinates estimated. With that, the movement of tectonic plates over time was minimized. In this way, from the calculation of discrepancies (trends) and with the clarifications provided in the adjustment, it was possible to perform the calculation of accuracies. According to the results, it was concluded that the method of relative positioning with the use of computational application and commercial use of receivers of dual frequency continues to be the most accurate method, regardless of the length of the baseline. The performance of relative positioning with a frequency receivers, involving short baselines also showed excellent results. In this case, at 64.3% of the results the accuracy was millimeter. It should be noted the potential of the IBGE-PPP and AUSPOS, which showed good results. In addition, these processing services are free and the users need only a receiver. / Dentre as tecnologias espaciais de posicionamento, destaca-se o GNSS (Global Navigation Satellite System), que é amplamente empregado em diversas aplicações na área de Geodésia, entre outras. O Posicionamento por Ponto Preciso (PPP) tem se mostrado uma poderosa ferramenta para aplicações geodésicas e geodinâmicas. O posicionamento relativo é ainda o método mais utilizado para determinação de coordenadas em levantamentos geodésicos de precisão. Contudo, o PPP está cada vez mais em evidência e tem proporcionado resultados satisfatórios. Diante do exposto, resta saber, dentre as técnicas mencionadas, qual apresenta resultados mais acurados atualmente. Os dados utilizados neste trabalho foram coletados pelas estações da RBMC (Rede Brasileira de Monitoramento Contínuo dos Sistemas GNSS) disponibilizados pelo IBGE (Instituto Brasileiro de Geografia e Estatística), referentes à data 01 de janeiro de 2014. Para análise do PPP foi utilizado o serviço gratuito online IBGE-PPP, e para análise do posicionamento relativo estático foram utilizados o serviço de posicionamento online gratuito AUSPOS, que processa os dados em rede, com uso do software científico Bernese, e o software comercial LGO (Leica Geo Office), que foi utilizado para processamento de linhas de base simples e de múltiplas linhas de base (ajustamento vetorial). Os dados GPS foram processados variando o intervalo de rastreio, abrangendo os intervalos de 1, 2, 4, 6, 8, 10 e 12 horas. No IBGE- PPP e no AUSPOS os resultados fornecidos são referenciados ao IGb08 (ITRF2008) na época de coleta dos dados. Para o processamento dos dados no LGO as coordenadas das estações base, disponibilizadas em SIRGAS2000, época 2000,4, foram transformadas e atualizadas para o sistema de referência IGb08 (ITRF2008) na época de coleta dos dados. Assim, as coordenadas estimadas no LGO também foram estimadas no IGb08 na época de coleta dos dados. Na sequência, as coordenadas estimadas no LGO, IBGE-PPP e AUSPOS foram comparadas com as coordenadas disponibilizadas nos descritivos das estações da RBMC, que também foram transformadas e atualizadas para o mesmo sistema de referência e época das coordenadas estimadas. Com isso, o deslocamento das placas tectônicas ao longo do tempo foi minimizado. Desta forma, a partir do cálculo das discrepâncias (tendências) e com as precisões disponibilizadas no ajustamento, foi possível realizar o cálculo das acurácias. De acordo com os resultados obtidos, conclui-se que o método de posicionamento relativo com o uso de aplicativo computacional comercial e uso de receptores de dupla frequência continua sendo o método mais acurado, independentemente do comprimento da linha de base. A performance do posicionamento relativo com receptores de uma frequência, envolvendo linhas de base curtas, também apresentou ótimos resultados. Neste caso, em 64,3% dos resultados a acurácia foi milimétrica. Deve-se salientar a potencialidade do IBGE-PPP e do AUSPOS, que apresentaram bons resultados. Além disso, esses serviços de processamento são gratuitos e o usuário deve dispor de apenas um receptor.