3Cat-3/MOTS nanosatellite mission for optical multispectral and GNSS-R Earth Observation: concept and analysis

The 3Cat-3/MOTS (3: Cube, Cat: Catalunya, 3: 3rd CubeSat mission/Missió Observació Terra Satèl·lit) mission is a joint initiative between the Institut Cartogràfic i Geològic de Catalunya (ICGC) and the Universitat Politècnica de Catalunya-BarcelonaTech (UPC) to foster innovative Earth Observation (EO) techniques based on data fusion of Global Navigation Satellite Systems Reflectometry (GNSS-R) and optical payloads. It is based on a 6U CubeSat platform, roughly a 10 cm × 20 cm × 30 cm parallelepiped. Since 2012, there has been a fast growing trend to use small satellites, especially nanosatellites, and in particular those following the CubeSat form factor. Small satellites possess intrinsic advantages over larger platforms in terms of cost, flexibility, and scalability, and may also enable constellations, trains, federations, or fractionated satellites or payloads based on a large number of individual satellites at an affordable cost. This work summarizes the mission analysis of 3Cat-3/MOTS, including its payload results, power budget (PB), thermal budget (TB), and data budget (DB). This mission analysis is addressed to transform EO data into territorial climate variables (soil moisture and land cover change) at the best possible achievable spatio-temporal resolution.Peer ReviewedPostprint (published version

Single-pass soil moisture retrievals using GNSS-R: lessons learned

In this paper, an algorithm to retrieve surface soil moisture from GNSS-R (Global Navigaton Satellite System Reflectometry) observations is presented. Surface roughness and vegetation effects are found to be the most critical ones to be corrected. On one side, the NASA SMAP (Soil Moisture Active and Passive) correction for vegetation opacity (multiplied by two to account for the descending and ascending passes) seems too high. Surface roughness effects cannot be compensated using in situ measurements, as they are not representative. An ad hoc correction for surface roughness, including the dependence with the incidence angle, and the actual reflectivity value is needed. With this correction, reasonable surface soil moisture values are obtained up to approximately a 30° incidence angle, beyond which the GNSS-R retrieved surface soil moisture spreads significantly.This work has been funded by the Spanish MCIU and EU ERDF project (RTI2018-099008-B-C21) “Sensing with pioneering opportunistic techniques” and grant to ”CommSensLab-UPC” Excellence Research Unit Maria de Maeztu (MINECO grant MDM-2016-600), and by a Doctorat Industrial grant from ICGC.Peer ReviewedPostprint (published version

Sensitivity to Soil Moisture and Observation Geometry of Spaceborne GNSS-R Delay-Doppler Maps

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Thanks to the successful operations of the UK TDS-1 and NASA CYGNSS GNSS-R missions, a wealth of Delay-Doppler Maps (DDM) are being measured from the ocean, but also from land reflections. Using the land reflected DDM, several studies are being conducted to retrieve the land geophysical parameters, such as soil moisture, vegetation depth, and biomass. Although they have shown the dependence of the land geophysical parameters on the DDM, it is also shown that many other parameters impact the DDM. This work presents the impacts of some parameters on the DDM. For the systematical and efficient study, an E2E simulator is used. The simulator generates the synthesized DDM reflected over land varying the input parameters, which are the specular point position on the Earth, the elevation angle at the specular points, soil moisture, etc. From the simulation results, the relation between the input parameters and the DDM is individually analyzed, providing the clue to the retrieval algorithm of the geophysical parameters.Peer ReviewedPostprint (author's final draft

Estudi de viabilitat d'un Missió Teledetecció multiespectral basada en un CubeSat 6U estàndard

This project analyzes the feasibility of boarding a medium resolution multipectral payload on a 6 unit CubeSat for Earth Remote Sensing purposes. The project should include the conceptual design of the payload and the satellite bus architecture and requirements, as well as perform the complete mission analysis (e.g. orbital propagator, thermal analysis, power budget, communications budget...)

Estudi de viabilitat d'un Missió Teledetecció multiespectral basada en un CubeSat 6U estàndard

This project analyzes the feasibility of boarding a medium resolution multipectral payload on a 6 unit CubeSat for Earth Remote Sensing purposes. The project should include the conceptual design of the payload and the satellite bus architecture and requirements, as well as perform the complete mission analysis (e.g. orbital propagator, thermal analysis, power budget, communications budget...)

Estudi de viabilitat d'un Missió Teledetecció multiespectral basada en un CubeSat 6U estàndard

This project analyzes the feasibility of boarding a medium resolution multipectral payload on a 6 unit CubeSat for Earth Remote Sensing purposes. The project should include the conceptual design of the payload and the satellite bus architecture and requirements, as well as perform the complete mission analysis (e.g. orbital propagator, thermal analysis, power budget, communications budget...)

Generic performance simulator of spaceborne GNSS-Reflectometer for land applications

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Nowadays, the space missions employing the global navigation satellite system reflectometry (GNSS-R) are UK TDS-1, NASA CYGNSS, and the Chinese BuFeng-1A/B twin satellites, part of the first Chinese global navigation satellite system reflectometry (GNSS-R) satellite mission. They provide delay-Doppler map (DDM) measurements reflected from the land as well as the ocean. Using land reflected DDMs, several studies have been conducted to retrieve land geophysical parameters, such as soil moisture and biomass. Despite the clear dependence on these parameters, many other parameters impact the DDMs as well, such as topography, surface roughness, etcPostprint (published version

High resolution soil moisture retrieval using optical and GNSS-R airborne data

Soil moisture is a key indicator for the management of a resource as precious and scarce as water. Sectors such as agriculture, environmental monitoring, and territory management, need to know the soil hydrological stress to take the appropriate actions. This work describes the second campaign conducted in the framework of the HUMIT project to test the readiness of data fusion techniques to retrieve high resolution soil moisture from hyperspectral and GNSS-R data. The results of the HUMIT project support the feasibility of a combined 6U CubeSat optical and GNSS-R mission for soil moisture monitoring. This second flight was carried out on October 22 nd 2018 near Balaguer (41.79° N, 0.80° E), over an agricultural area of approximately 4 km 2 .Peer ReviewedPostprint (published version

3CAT-3/MOTS, an experimental nanosatellite for multispectra and GNSS-R Earth Observation: Mission concept and analysis

The 3 Cat-3/MOTS mission is a joint initiative between the Institut Cartogràfic i Geològic de Catalunya (ICGC) and the Universitat Politècnica de Catalunya-BarcelonaTech (UPC) to foster new and innovative technologies on Earth Observation (EO) based on data fusion of Global Navigation Satellite Systems Reflectometry (GNSS-R) and optical payloads on a 6U CubeSat platform [1]. Since 2012, there has been a growing trend to use small satellites [2]. Small satellites possess intrinsic advantages over larger platforms in terms of cost, flexibility and scalability and have also made possible constellations of a great number of satellites at an affordable cost. The latest technological advances and the miniaturization of most devices are also key factors to explain the boom of small satellites. 3 Cat-3/MOTS mission analysis will be addressed to transform EO data into territorial climate variables (information) at the best possible spatial-temporal resolution.Peer Reviewe

3CAT-3/MOTS, an experimental nanosatellite for multispectra and GNSS-R Earth Observation: Mission concept and analysis

The 3 Cat-3/MOTS mission is a joint initiative between the Institut Cartogràfic i Geològic de Catalunya (ICGC) and the Universitat Politècnica de Catalunya-BarcelonaTech (UPC) to foster new and innovative technologies on Earth Observation (EO) based on data fusion of Global Navigation Satellite Systems Reflectometry (GNSS-R) and optical payloads on a 6U CubeSat platform [1]. Since 2012, there has been a growing trend to use small satellites [2]. Small satellites possess intrinsic advantages over larger platforms in terms of cost, flexibility and scalability and have also made possible constellations of a great number of satellites at an affordable cost. The latest technological advances and the miniaturization of most devices are also key factors to explain the boom of small satellites. 3 Cat-3/MOTS mission analysis will be addressed to transform EO data into territorial climate variables (information) at the best possible spatial-temporal resolution.Peer Reviewe