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Radio Frequency Interference (RFI) are disturbing signals in the radio frequency spectrum, which can arise from various external sources, intentional or not. These disturbances can degrade the performance of other signals present in the band. One of such bands of remarkable importance is the 23.8 GHz band, used to retrieve the water vapor concentration in the atmosphere. The Frequency Allocations in Remote Sensing (FARS) Technical Committee from the Geoscience and Remote Sensing Society (GRSS) tasked the development and testing of a low-power consumption pico-satellite payload to monitor the possible presence of RFI in the 24 GHz band due to 5G services. This paper presents the testing and characterization of the RFI detection payload., This work was sponsored by the Frequency Allocations in Remote Sensing (FARS) Technical Committee of the IEEE Geoscience and Remote Sensing Society (GRSS). This project was also sposored in part by the project ”GENESIS: GNSS Environmental and Societal Missions – Subproject UPC”, Grant PID2021-126436OB-C21 funded by the Ministerio de Ciencia e Investigación (MCIN)/Agencia Estatal de Investigación (AEI)/10.13039/501100011033 and EU FEDER “Una manera de hacer Europa”., Peer Reviewed, Postprint (author's final draft)

With CubeSats having evolved beyond their initial educational purpose and now being employed across a diverse range of applications, more and more private enterprises are deploying large constellations for a plethora of applications. This increased popularity and enhanced performance of the nanosatellite form factor has led to heightened demands for reliability and cost efficiency. Presently, commissioning subsystem providers has become challenging, with a prevailing trend towards seeking fully integrated platforms in the market. Paradoxically, CubeSats are now less accessible to universities and research institutions than they were a few years ago.To address these challenges, the PocketQube concept emerged. Making up the picosatellite class, and measuring 50x50x50 mm 3 , they provide a cost-effective alternative, particularly for educational purposes. Students working with PocketQubes encounter design challenges akin to those faced with larger satellites. This paper comes in continuation of the IEEE-GRSS "Open PocketQube Kit" educational initiative, developed by the NanoSat-Lab at the Universitat Politecnica de Catalunya and is focused along the integration and testing of the subsystems, as well as performing a full system validation and an environmental testing.The initiative has resulted in the development of three distinct PocketQube models: Po Cat-1 equipped with a VGA camera, and Po Cat-2 and Po Cat-3 designed for monitoring radio-frequency interference at L-band (1-2 GHz) and K-band (24-25 GHz) respectively. The latter two have undergone a series of drone campaigns in the first half of 2024, sponsored by the Frequency Allocations in Remote Sensing (FARS) Technical Committee of the IEEE Geoscience and Remote Sensing Society (GRSS)., This work has been developed as part of the IEEE Geoscience and Remote Sensing Society ”Open PocketQube Kit” educational initiative and it will be openly distributed when completed. Additionally, it was part of the project ”GENESIS: GNSS Environmental and Societal Missions – Subproject UPC”, Grant PID2021-126436OB-C21 funded by the Ministerio de Ciencia e Investigacion (MCIN)/Agencia Estatal de Investigación (AEI)/10.13039/501100011033 and EU FEDER “Una manera de hacer Europa”., Peer Reviewed, Postprint (author's final draft)

Due to an increasing entry barrier to both universities and researchers in conventional small satellites initiatives, there has been an emergence of smaller and cheaper spacecrafts like PocketQubes, a much more affordable option for public entities. Considering all that, this thesis has been developed as part of a project undertaken by the UPC NanoSat Lab which started as an IEEE GRSS initiative named PoCat. The objective of the PoCat project is to design, develop and test three single unit picosatellites with each featuring the following different payloads, a Video Graphics Array (VGA) camera, a Radio Frequency Interference (RFI) monitoring system at L-band and an RFI monitoring system at K-Band. The three satellites, however, contain the same avionics core composed of the On-Board Computer (OBC), Communication System (COMMS), Attitude Determination and Control System (ADCS) and Electrical Power Supply System (EPS). Given this scenario, the purpose of this report is to give insights regarding the on-board software development for PocketQubes, which as of writing this report there is still room for debate concerning their standardization. Conceptually, the OBC system acts as the brain of the satellite. As for the technology, the OBC is build upon the STM32L476 microcontroller due to its memory storage, power efficiency and processing power. Performing the power management as well as giving response to events are the main objectives of the OBC. In order to do the latter, the flight software is based on a Real-Time Operating System (RTOS) called FreeRTOS which has been selected above other Operating System (OS) due to its predictability, compliance with the required deadlines, support, available documentation, compatibility with previous projects, licensing costs, and certifications. According to FreeRTOS, the program is structured into independent tasks where each one features a priority in line with their criticality. Then, the project is constituted by eight tasks

In the last decades, the number of wireless devices has notably increased, and improper RF filtering has resulted in an increase in Radio Frequency Interference (RFI). At L-band this is due to a plethora of reasons: from VHF/UHF harmonics, higher frequency band (e.g. WiFi boosters) emissions, or even intentional RFI created by Personal Privacy Devices (PPD), all these have resulted in a degradation of both Active and Passive Microwave Remote Sensing [1], [2]. Almost simultaneously, there has been an explosion of smallsats, notably following the CubeSat and PocketQube [3] form factors, both being excellent hands-on project topics for introducing students into the aerospace domain [4].In these circumstances, the IEEE Geoscience and Remote Sensing (GRSS) Open PocketQube Kit [5] initiative was started. The goal is to develop a set of flight ready Picosatellites with Earth Observation payloads complete with assembly, integration and testing tutorials and video tutorials. Each of these PocketQubes, while identical in all other regards, will house different Remote Sensing oriented payloads. One of them, and the focus of this work, is a L-band (1-2 GHz) Radio Frequency Interference Monitor, notably for the L1, L2 and L5-bands of GNSS [6] systems, and the 1400-1427 Mhz band reserved for passive observations., This payload has been developed as part of the IEEE Geoscience and Remote Sensing Society ”Open PocketQube Kit” educational initiative and it will be openly distributed when completed. Additionally, it was part of the project ”GENESIS: GNSS Environmental and Societal Missions – Subproject UPC”, Grant PID2021-126436OB-C21 funded by the Ministerio de Ciencia e Investigación (MCIN)/Agencia Estatal de Investigación (AEI)/10.13039/501100011033 and EU FEDER “Una manera de hacer Europa”., Peer Reviewed, Postprint (author's final draft)

Due to the recent licensing of the 26 GHz 5G communications bands, the passive microeaves Remote Sensing community is concerned that spurious out-of-band emissions could interfere with the measurements acquired in the 23.8 GHz water vapor resonance band. For this reason, the Frequency Allocations in Remote Sensing (FARS) Technical Committee from the IEEE Geoscience and Remote Sensing Society (GRSS) has procured the development of a RFI monitoring payload to detect possible interferences in the 24 to 25 GHz band. This payload is compatible with the PocketQubes being developed in the framework of the "IEEE GRSS Open PocketQube Kit" educational initiative, and it will be used to measure and determine the occurrence of possible interferences close to the 23.8 GHz water vapor band. This work presents the design, implementation and testing of the 24 to 25 GHz RFI monitoring payload designed for a 1P PocketQube., This work was sponsored by the Frequency Allocations in Remote Sensing (FARS) Technical Committee of the IEEE Geoscience and Remote Sensing Society (GRSS). This project was also sposored in part by the project ”GENESIS: GNSS Environmental and Societal Missions – Subproject UPC”, Grant PID2021-126436OB-C21 funded by the Ministerio de Ciencia e Investigación (MCIN)/Agencia Estatal de Investigación (AEI)/10.13039/501100011033 and EU FEDER “Una manera de hacer Europa”., Peer Reviewed, Postprint (author's final draft)

The project developed in this thesis consists of the assembly, integration, verification and testing of the different subsystems of a PocketQube (Electrical Power Supply, Altitude Determination and Control System, On-Board Computer and Communications System). In this thesis, after a soldering training, the different PCBs of the PocketQube have been assembled.Subsequently, different tests have been designed and executed in order to verify the correct behaviour of the PCB, first electrically and then functionally. Lastly, the payloads had been integrated and tested as a whole in an Electrical Ground Support Equipment., El proyecto desarrollado en este trabajo de fin de grado consiste en el ensamblaje, integración, verificación y prueba de los diferentes subsistemas de un PocketQube (Electrical Power Supply, Altitude Determination and Control System, On-Board Computer and Communications System). En este trabajo de fin de grado, después de realizar un entrenamiento de soldadura, se han ensamblado las diferentes PCB del PocketQube. Posteriormente, se diseñaron y llevaron a cabo diferentes tests para verificar el correcto funcionamiento de las PCB, primero a nivel eléctrico y luego funcional. Por último, se integraron y probaron las placas como un todo utilizando el "Electrical Ground Support Equipment", El projecte desenvolupat en aquest treball de fi de grau consisteix en l’assemblatge, integració, verificació i prova dels diferents subsistemes d’un PocketQube (Electrical Power Supply, Altitude Determination and Control System, On-Board Computer and Communications System). En aquest treball de fi de grau, després de realitzar un entrenament de soldadura, s’han soldat les diferents PCB del PocketQube. Posteriorment, s’han dissenyat i executat diferents tests per verificar el correcte funcionament de la PCB, primer a nivell elèctric i després funcional. Finalment, s’han integrat i provat les places com a un tot en un ‘Electrical Ground Support Equipment’

CubeSats are now serving a wide range of applications beyond their original educational intent. Private companies are deploying large constellations for Earth observation and machine–to–machine communications. Their growing popularity and increased performance have raised the demand for reliability and costs. Today, it is becoming increasingly difficult to find subsystems providers, and the trend is to find fully integrated platforms on the market. Therefore, paradoxically, CubeSats are becoming less accessible to universities and research institutions than a few years ago. To overcome these problems, the PocketQube concept was invented. PocketQubes measure 50 × 50 × 50 mm³ and offer a cost-effective option, notably for education. These picosatellites can perform simple missions like Internet of Things communications or upper-atmosphere observations, ionosphere studies, or signal integrity tasks, while students face design challenges similar to larger satellites. This article presents the IEEE Geoscience and Remote Sensing Society (GRSS) “Open PocketQube Kit” educational initiative. Developed by the NanoSat Lab at the Polytechnic University of Catalonia (UPC), it is an affordable open source educational kit featuring a complete PocketQube structure with all the subsystems: an electrical power supply (EPS), attitude determination and control system (ADCS), an STM32-based onboard computer (OBC), long-range (LoRa) communications, and payload. Three different PocketQube models have been developed: Po Cat-1, with a video graphics array (VGA) camera, and Po Cat-2 and Po Cat-3 for monitoring radio-frequency interference (RFI) at the L-band (1–2 GHz) and K-band (24–25 GHz) to track 5G spectrum emissions., This work was sponsored by the GRSS Directorate of Education and FARS Technical Committee., Peer Reviewed, Postprint (published version)

With the entry barrier for conventional small satellites continuously increasing for uni- versities and researches, this thesis means to promote a more accessible option in the form of a single unit picosatellite (1P). In this report, the design, implementation and testing procedures, alongside with the general mode of operation of these otherwise called PocketQubes will be presented. Three different configurations will be defined by means of three payloads: a VGA camera and two RFI Monitoring Receivers, at L-band and K-band. The avionics, constituting of an EPS, OBC, COMMS and an ADCS will remain mostly unchanged between the three variants. An IEEE GRSS initiative, the project has taken place, from designing to implementation and testing, within UPC?s NanoSat Lab, and is scheduled to be delivered in the shape of a kit, containing the Flight Models fully equipped with a set of manuals and tutorials for assembly, testing and operation, at the end of 2022. Additionally, a flight opportunity is envisioned for two of these PocketQubes aboard the NanoSat Lab?s future 3Cat-8 mission., Con la barrera de entrada de los pequeños satélites convencionales en continuo aumento para las universidades e investigadores, esta tesis pretende promover una opción más accesible en forma de un picosatélite de una sola unidad (1P). En este informe, el diseño, la implementación y los procedimientos de prueba, junto con el modo general de funcionamiento de estos, también llamados PocketQubes, serán presentados. Se definirán tres configuraciones diferentes mediante tres cargas útiles: una cámara VGA y dos receptores de monitorización RFI, uno en banda L y otro en banda K. La aviónica, constituida por los subsistemas EPS, OBC, COMMS y ADCS, permanecer a prácticamente sin cambios entre las tres variantes. El proyecto, una iniciativa del GRSS del IEEE, se ha llevado a cabo desde el diseño hasta la implementación y las pruebas en el NanoSat Lab de la UPC, y está previsto que se entregue en forma de kit, conformado por los modelos de vuelo, Amb la barrera d’entrada als petits satèl·lits convencionals en augment continu per a les universitats i investigadors, aquesta tesi tracta de facilitar l’accés a una opció més assequible, en forma d’un picosatèl·lit d’1P. En aquest treball es presenten els procediments de disseny, implementació i proves realitzades, conjuntament amb els modes generals de funcionament d’aquests satèl·lits, anomenats PocketQubes. Es definiran tres configuracions diferents, segons la carrega útil a bord: una càmera VGA i dos sensors de RFI, un en banda L i l’altre en banda K. L’aviònica, constituïda per una EPS, una OBC, un sistema COMMS i el mòdul ADCS, romandrà pràcticament sense alteracions entre els tres models. Aquest projecte és una iniciativa del GRSS de l’IEE, i s’ha executat, des del disseny fins a la implementació i verificació, a les instal·lacions del NanoSat Lab de la UPC, i està pendent de ser entregat com a kit complet, incloent-hi els models de vol i el conjunt de manuals i tutorials de muntatge, proves i la operació, a finals de 2022. A més, es preveu una oportunitat de vol per a dos d’aquests PocketQubes a bord de la futura missió 3Cat-8 del NanoSat Lab.