Publications
Publication Types
Throughout the development of ISTSat-1 the team has published a lot of scientific materials and has made several contributions to the engineering world. Here you will be able to find all of the work published by the ISTNanosat team for the ISTSat-1 project.
Published content
Master's theses
Published content
Throughout the years the ISTNanosat team members have made several contributions to the engineering world and have had the oportunity to participate in scientific conferences.
Below are some of the scientific materials that have been published regarding the ISTSat-1 project organized by platform (conference, journal, event, etc.) and year.
- IJSCN 2022
- ASME 2021
- URSI 2019
- Aerospace Journal
- 10th ECS
- OSCW 2018
International Journal of Satellite Communications and Networking
Abstract
The use of space-based Automatic Dependent Surveillance-Broadcast (ADS-B) receivers to extend aircraft surveillance beyond line-of-sight communication has been discussed since the late 2000s and has been demonstrated in various missions. Although recent demonstrations have relied on small CubeSat platforms, the use of the smallest possible form factor has not been explored. This paper describes development of a spacecraft representing the first use of a 1 U CubeSat platform for aircraft tracking. To comply with the platform’s limited power budget, the receiver departs from the typical application of FPGA boards to decoding ADS-B signals and instead employs a general microprocessor. The spacecraft also features some innovations over traditional CubeSat platforms, such as distributed system-level software amenable to extensive code reuse, redundant communications mechanisms, and software-based radiation mitigation strategies. Having designed, built, and integrated all subsystems, as well as performed multiple test campaigns at system and subsystem level, the team now aims at completing formal functional and environmental testing before undergoing the launch campaign, foreseen for 2022.
Keywords
ADS-B, CubeSat, low-power, miniaturization, telecommunications
Authors
João Paulo Monteiro, Alberto Cunha, Alexandre Silva, Carlos Fernandes, Diogo Neves, Fabian Näf, Gonçalo Tavares, José Freitas, João Pinto, Moisés Piedade, Nuno Ramos, Paulo Gil, Paulo Macedo, Rúben Afonso, Renato Encarnação, Rodrigo Ramos, Tomás Almeida, Rui Rocha
Title
ISTSat-1, a space-based Automatic Dependent Surveillance-Broadcast demonstration CubeSat mission
Document type
Article
Date
January 2022
ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
Abstract
In this paper, we define Model Based Systems Engineering (MBSE) as a set of different approaches which vary in scope and in purpose, as opposed to defining it as a monolithic concept. To do so, we inductively extract common themes from papers proposing new MBSE methods based on the type of Systems Engineering (SE) artifacts produced and the expected benefits of MBSE implementation. These themes are then validated against the experiences depicted in a second set of papers evaluating the deployment of MBSE methods in practice. We propose a taxonomy for MBSE which identifies three main categories: system specification repositories, system execution models, and design automation models. The proposed categories map well onto common discussions of the nature of the SE activity, in that the first is employed in the management of system development processes and the second in the understanding of system performance and emergent properties. The third category is almost exclusively discussed in an academic context and is therefore more difficult to relate to SE practice, but its features are clearly distinct from the other two. The proposed taxonomy clarifies what MBSE is and what it can be, therefore helping focus research on the issues that still prevent MBSE practice from living up to expectations.
Keywords
systems design, systems engineering, design theory and methodology, data/information modeling
Authors
João Paulo Monteiro, Paulo Gil, Rui Rocha
Title
A Taxonomy for Model-Based Systems Engineering
Document type
Paper
Date
November 2021
13th Congress of the Portuguese Committee of URSI ''Space: Challenges and Opportunities''
Abstract
An analysis of Electromagnetic Compatibility (EMC) for space environments is described and performed by the EMC area of the Testing and Calibration Laboratory (LEC) from ANACOM. This analysis focuses on a feasibility study of EMC testing for space objects at this facility, taking into account the ECSS standard for EMC, and the ISTSat-1 CubeSat from the IST as a case study. Therefore, a study of the EMC area capabilities is done concerning its normative references, equipment facility, frequency ranges, test levels and experience, which are essential for EMC test campaigns applied to space objects and, in particular, to the ISTsat-1 CubeSat.
Keywords
Electromagnetic Compatibility, Electromagnetic, Interference, Electromagnetic Susceptibility, ECSS standard, IEC, Standard, CISPR Standard, MIL Standard.
Authors
João Pinto, António Azevedo and António Sampaio.
Title
Electromagnetic Compatibility Analysis for Space Environments
Document type
Paper
Date
December 2019
Aerospace Journal
Abstract
Large-scale space projects rely on a thorough Assembly, Integration, and Verification (AIV) process to provide the upmost reliability to spacecraft. While this has not traditionally been the case with CubeSats, their increasing role in space science and technology has led to new verification approaches, including in educational CubeSats. This work describes the integration and verification approach for ISTSat-1, which is an educational CubeSat from the Instituto Superior Técnico in Portugal that partially discards the typical stage-gate approach to spacecraft development in favor of a more iterative approach, allowing for the system-level verification of unfinished prototypes. Early verification included software functional testing on a flatsat model, thermal vacuum and vibration testing on a battery model, ionizing radiation testing on the on-board computer, and non-ionizing radiation (EMC) testing on all subsystems. The testing of functional prototypes at an early development stage led to uncovering system-level errors that would typically require hardware redesign at a later project stage. The team considers the approach to be useful for educational projects that employ a small, co-located team with low non-recurring engineering costs.
Keywords
CubeSat; iterative development; flatsat; ionizing radiation; EMC; battery qualification.
Authors
João P. Monteiro, Rui M. Rocha, Alexandre Silva, Rúben Afonso and Nuno Ramos.
Title
Integration and Verification Approach of ISTSat-1 CubeSat
Document type
Article
Date
October 2019
10th European CubeSat Symposium
Descrition
At the 10th European Cubesat Symposium the ISTNanosat team presented a poster describing ISTSat-1’s mission which is to test a compact ADS-B receiver and antenna.
The main points covered by the document are:
- The antenna’s characteristics;
- A characterization of the receiver;
- A description how the ADS-B messages are processsed within the Payload subsystem.
Authors
João Pinto, Tomás Almeida, Luís Pereira, Gonçalo Tavares, Carlos Fernandes, Alberto Cunha and Rui Rocha.
Title
A Compact ADS-B Receiver for a 1U CubeSat
Document type
Poster
Date
December 2018
Open Source CubeSat Workshop 2018
Descrition
At 2018’s Open Source CubeSat Workshop the ISTNanosat team presented a poster describing ISTSat-1’s INCP protocol developed by the team. This is the highest level protocol and is used for communication between the spacecraft’s subsystems which includes monitorization, control, retrieval of telemetry and experimental results.
The main points covered by the document are:
- Commands and diagnostics;
- Telemetry retrieval and even reporting;
- Message format;
- Dagnostic reference;
- Data variables reference;
- Event reference;
- Commands reference.
Authors
Alexandre Silva and Rui Rocha.
Masters' Theses
Did you know that most of ISTSat-1 was created in-house? This was possible since many students from various courses at IST joined our team and developed their Master’s theses with us. Each of them worked on a small part of the satellite, always iterating on an older student’s work.
Below are all the thesis developed for the ISTSat-1 project, sorted by author.
- Alexandre Silva
- Diogo Neves
- João Gavinho
- Luís Pereira
- Luís Ramos
- Nuno Ramos
- Pedro Coelho
- Rúben Afonso
- Tomás Almeida
Development of the ISTnanosat-1 Ground Segment
Abstract
In this report we propose a solution for the ground segment of the ISTNanosat-1.
The ISTNanosat-1 is a CubeSat, a type of artificial satellite, currently under development by students and faculty from IST along with amateur radio experts from AMRAD and AMSAT-CT. As with any space- craft, it will need to be monitored, controlled and results from scientific experiments have to be retrieved.
The ground segment is the necessary infrastructure on Earth that will permit these tasks.
The ISTNanosat-1 Ground Segment presents a system capable of telemetry retrieval and issuing instructions to the satellite. All of the relevant information is then shown to the users using a web application. Furthermore, properly authorized users have the capability to issue the aforementioned instructions. The developed ground segment is composed by multiple ground stations controlled by Core server. In this centralized design, the Core communicates with the satellite trough the ground stations, which serve as gateways, using the designed and implemented ISTnanosat Control Protocol (INCP). In the Core, several services permit for the for data and error retrieval, command and diagnostics
execution and security of the ground-space segment link.
Keywords
Satellite, CubeSat, ISTNanosat, Ground Segment, Ground Station
Author
Alexandre Simões Silva
Course
MSc Telecommunications and Informatics Engineering
Supervisors
Prof. Rui Manuel Rodrigues Rocha
Date
May 2017
Control Algorithm for ISTsat-1
Abstract
The ISTsat-1 is a cubesatsatellite developed by students from Instituto Superior Técnico (IST) under the ESA educational program Fly Your Satellite. The objective of this mission is to monitor and characterize the ADS-B signals from aircraft. One of the priorities of the satellite platform is to point it into the desired direction with a certain level of accuracy to accomplish the mission as well as to ensure the satellite does not get excessive rotation. This work focuses the development of the Attitude Determination and Control System which will ensure these conditions. The system was developed to be integrated into the physical platform previously designed for the onboard computer. The challenge to surpass is to ensure the satellite reaches the pointing requirements posed by the payload while using a low-cost and low- power platform. To evaluate the possible solutions the Simulink tool was used, allowing to model the satellite and the environment to which the satellite will be subjected. Afterwards, the problem was studied using computational light attitude estimation algorithms. Finally, the attitude determination solutions allowed to study control solutions also focused on computational efficiency. The results demonstrate that it is possible to use quick, efficient and low-cost solutions to develop satellites with low orientation requirements.
Keywords
Satellite, CubeSat, ISTsat, Attitude, Estimation, Control
Author
Diogo Pessanha Neves
Course
MSc Aerospace Engineering
Supervisors
Prof. Paulo Jorge Coelho Ramalho Oliveira
Prof. Rui Manuel Rodrigues Rocha
Date
July 2019
Power supply for ISTnanosat-1
Abstract
Developed in the IST, by students and teachers, the ISTNanosat – 1 is a project to develop an artificial satellite following a CubeSat design, consisting in 10 cm cubes used in a progressive assembly and hosting a scientific experiment and the control and communication modules.
This dissertation is intended to develop an EPS (Electrical Power System), which makes the acquisition, storage and distribution of ambient energy.
Ambient energy is gathered by solar panels mounted on the outer faces the of Nanosat that turns solar energy into electric power to be store in a battery and then converted to regulated outputs used to feed entire system.
The challenges that exist in the EPS project are the development and installation of the hardware architecture that allows recovering the system in case of failure,with limitations due to space, weight and budget available.
The first part, concerns the collection and storage of energy containing the Regulator for the energy supply gathered to loading bus in NanoSat. The second part is the development of the conversion and management system for supply voltages intended to other subsystems.
To make the control of EPS and communication with the central module its used dedicate processor, with all the software being planned to be developed.
Keywords
CubeSat, Satellite, Power System, Solar Panels, Batteries, Converters
Author
João Martim Correia Vilhena Gavinho
Course
MSc Electronics Engineering
Supervisors
Prof. Moisés Simões Piedade
Prof. Rui Manuel Rodrigues Rocha
Date
October 2015
Space Based ADS-B receiver for ISTsat-1
Abstract
A CubeSat is a 10 cm cube low-cost satellite with a mass up to 1.33 kg commonly launched into a Low Earth Orbit (LEO), which extends until an altitude of 2000 Km. The ISTsat-1 is the first nanosatellite developed by the ISTnanosat team. This satellite is intended to test the reliability of an aircraft tracking system namely the Automatic Dependent Surveillance – Broadcast (ADS-B) system, being its scientific payload.
The major requirement for the payload mission is related to the acquisition of signals while decoding ADS-B messages at the same time. This master thesis focuses on the description of the ADS-B mes- sages that are relevant to the algorithm developed in order to receive and decode them. Alongside, the possible architectures to overcome the mission requirements are described with particular attention to the ADS-B algorithm necessary to detect and decode ADS-B messages and the LPC4370 peripherals that will help to receive and sample the respective messages. Therefore, the several results acquired with the final solution are provided and a performance evaluation is given regarding the CPU usage and the power consumption.
Finally, a real test case is provided in order to understand the feasibility of the system in the earth’s surface and to guarantee that the system works as required.
Keywords
ISTSat-1, ADS-B, Mode-S message, LPC4370, algorithm
Author
Luís Filipe Brás Pinto Pereira
Course
MSc Telecommunications and Computer Engineering
Supervisors
Prof. Alberto Manuel Ramos da Cunha
Prof. Rui Manuel Rodrigues Rocha
Date
October 2019
ISTSAT-1 Mission Data Handling Architecture
Abstract
In this report we propose a solution to the Data Handling and Radio necessities of the ISTSAT- 1.
The ISTSAT-1 is a CubeSat, a small space satellite being developed by students and pro- fessors from IST. The main mission of the ISTSAT-1 is to test a small form factor ADS-B signal receiver. ADS-B signals are sent periodically by airplanes in order for airplanes to be trackable. The satellite will be controlled by a Ground Station.
The ISTSAT-1’s mission data handling architecture is a solution to the problem of handling the data captured by the satellite. This solution will allow for the characterization of the compact ADS-B receiver of the satellite. This architecture will also develop an intuitive user interface to display the captured data from the satellite. We also present a solution to the radio necessities of the Ground Station by use of Software Defined Radio.
Keywords
Satellite, ISTSAT-1, ground station, ADS-B, data handling, radio
Author
Luís Tavares De Ornelas Monteiro Ramos
Course
MSc Information Systems and Computer Engineering
Supervisors
Prof. Alberto Manuel Ramos da Cunha
Prof. Prof. Rui Manuel Rodrigues Rocha
Date
January 2019
Satellite Electrical Power System
Abstract
The Electrical Power System (EPS) is an electronic circuit board that is designed to supply and manage process the energy in an efficient way. This document describes the design architecture and circuits involved for an EPS deployed in the ISTsat ONE nano satellite project. The EPS generates energy through its solar panels which is stored in the battery and then, using DC-DC switching voltage regulators, converts it to the final voltage of +3.3 V and +5 V, supplying these voltage rails for the rest of the subsystems of the satellite. This architecture meets the performance and size requirements of CubeSat architecture (cubic shape with 10 cm of edge, satellite with less than 10 kg). The EPS is composed by various systems, namely: Maximum Power Point Tracking mechanism to achieve maximum efficiency in the conversion of solar energy, a 20.8 Wh battery, solar panels and redundant circuitry to continuously ensure the power supply to the satellite. The EPS is a subsystem of the ISTsat ONE and as such, it communicates with other subsystems present in the satellite sending data logs, error warnings as well as receiving commands.
Keywords
EPS, Electrical Power System, Battery, Space, CubeSat, Nano satellite, ISTsat ONE, Power System, DC/DC Converter, Solar Panel, Energy Management, Maximum Power Point tracker, Solar Panels
Author
Nuno Laranjeira Ramos
Course
MSc Electronics Engineering
Supervisors
Prof. Maria Beatriz Mendes Batalha Vieira Vieira Borges
Prof. Moisés Simões Piedade
Date
October 2018
ISTNanosat-1 Quality Assurance, Risk Management and Assembly, Integration and Verification Planning
Abstract
The ISTNanosat-1 is a 1U CubeSat developed in academic environment by students and teachers of IST with the primary objective of belonging to HUMSAT constellation, while developing technical and engineering skills in the participating students. Secondarily, it intends to take measurements on the Flyby phenomenon and serve as a technology demonstrator of a high speed ADC rad hard.
Inherent to the development of a project of this nature, the issues regarding quality, risk and AIV must be considered. Regardless of the academic environment in which the project is carried, it is required to ensure that the satellite is able to fulfill the intended mission and that the developed and testing is performed with the proper management. It was therefore developed within the frame of this work quality and risk management for the project, as well as the respective AIV plan, with particular focus on the test component.
The quality and risk management implemented focused on documentation and configuration management, risk management, selection and control of procurement, manufacturing, assembly and integration, as well as security and reliability considerations that guide the procedures and best practices to take into account in the project development.
Finally, the planned satellite AIV features high-level processes to be taken into consideration for the assembly and integration of ISTNanoSat-1, with the main focus on the planning of the test campaign for qualification and flight of the satellite. A complete test campaign was produced in agreement with the main standards of the space industry and taking into account the expected environment at launch or in orbit. Given the lack of definition if the launcher at this development stage, the test campaign was planned based on the utilization of the satellite in the worst case scenario.
The desirable implementation point was identified according to the requirements and space standards, being the achieved flexibility and lower restrictions compatible with the real needs of the development of a CubeSat. Moreover, the risks identified suggest continuous improvements to be implemented in the frame of the project. Regarding the presented test campaign, it is possible to be used to qualify the satellite for any possible scenario and plausible mission of a CubeSat. The work is therefore considered transverse and reusable for future projects of the same scope and can be seen as programmatic.
Keywords
istnanosat-1, cubesat, assembly, integration, testing, risk management, quality assurance
Author
Pedro Filipe Rodrigues Coelho
Course
MSc Aerospace Engineering
Supervisors
Prof. Rui Manuel Rocha
Prof. Moisés Simões Piedade
Date
May 2016
Attitude Determination and Control System for ISTNanosat-1
Abstract
An artificial satellite is a man-made object placed in the orbit of a celestial body. Depending on their mission, satellites have different sizes, orbits and subsystems. The ISTNanosat-1 is the first nanosatellite developed by Instituto Superior Técnico, respecting the 1U CubeSat format specifications. It is intended that the satellite will test several scientific modules and collect information about space. It takes part in the Humsat project, which aims to create a network of small satellites. The satellite possesses four main subsystems, which are responsible for energy storage, communications with ground stations, data control and handling, and attitude determination and control.
This dissertation consists in the development of the satellite’s attitude management and determination system, using an inertial measurement unit (IMU) with gyroscope, accelerometer and magnetometer. Possible architectures are discussed and a solution to the final module is proposed.
The aim of this project is to acquire data from the sensors and implement an attitude determination algorithm. Moreover, it addresses and projects redundancy and supply protection systems and communication interfaces with other modules and subsystems. A printed circuit board of the module in question is designed and produced. Testing and validation of the developed system are oriented to its use in space. The system is able to calculate its attitude at a temperature range between -20 °C and 40 °C, with an error inferior to 5o in the X and Y axes, and inferior to 20o in the Z axis.
Keywords
Euler angles, CubeSat, GNSS, ISTNanosat-1, Nanosat, Redundancy, On Board Computer, Inertial Measurement Unit
Author
Ruben Filipe Afonso
Course
MSc Electronics Engineering
Supervisors
Prof. Rui Manuel Rodrigues Rocha
Prof. Moisés Simões Piedade
Date
October 2016
Planar Antennas for CubeSat Missions
Abstract
CubeSats are a type of pico-satellites that have a standardized size of 10 x 10 x 10 cm3 (1U), or 1U multiples, and weigh less than 1.33 kg per cubic unit. A few challenges arise when designing an antenna to be integrated in the CubeSat’s small structure. Miniaturization techniques must be used to shrink antenna size and deployable antennas solutions can be used when bigger antenna apertures are needed e.g., in applications that require a high gain antenna. Also, special challenges arise due to the harsh environment in space.
In this thesis, two different planar antennas for CubeSat applications are designed and fabricated. First, a patch antenna for the ISTsat-1 CubeSat, is developed. Secondly, a reflect array (RA) antenna is developed for a possible ISTsat-2 mission. The antenna for ISTsat-1 operates in the L band, more specifically 1090 MHz, and is for an automatic dependent surveillance – broadcast mission (ADS-B). The second antenna operates in the Ka uplink band of 27 – 31 GHz, and can be used for multiple applications, e.g. fast mobile broadband access.
During the development of the antennas in this thesis, simulation studies are performed, as well as the fabrication of prototypes, and specific experimental tests. In regard to the ISTsat-1 ADS-B antenna, a fully functional, flight ready antenna, is presented.
Keywords
CubeSat, ISTsat-1, Satellite Antennas, Planar Antennas, Patch Antenna, Reflect Array
Author
Tomás Alexandre Saltão Almeida
Course
MSc Electronics Engineering
Supervisors
Prof. Carlos António Cardoso Fernandes
Prof. Jorge Manuel Lopes Leal Rodrigues da Costa
Date
November 2018