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.

The Remote sensing and Interference detector with radiome-Try and vegetation Analysis (RITA Payload) [1] is a development of the UPC NanoSat Lab, aimed at Earth Observation (EO). It is one of the winners of the Second IEEE GRSS Student Grand Challenge, and will fly on-board AlainSat-1, a 3U CubeSat developed by the National Space Science and Technology Center (NSSTC) of the United Arab Emirates.RITA hosts three experiments. An L-band microwave radiometer (MWR) will gather data of soil moisture and sea ice thickness and concentration, aided with a Radio-frequency Interference (RFI) detection algorithm. A LoRa transceiver will perform on-demand execution of the EO experiments [2]. Finally, a Near-Infrared (NIR) Hyperspectral Camera will gather data for vegetation monitoring, agriculture applications, hydrology and coastal and inland waters mapping, among others [3].This work is focused on the calibration and validation of the Hyperspectral imager, at optical, electronic and spectral levels, as well as in the verification of its performance to measure Normalized Difference Vegetation Index (NDVI).

Earth observation satellite missions are becoming increasingly important and have been also boosted by the appearance of small satellites, affordable to small companies and universities. Technology miniaturization and the reduction in power consumption have been a key point in the reduction of the dimensions of these spacecrafts, being able to integrate powerful payloads in a very limited space. In missions where the observations are made at lower frequency bands, the antenna dimensions limit the achievable angular resolution. For this reason, significant investments are being made to develop antenna deployment systems for small satellites, and the deployable antennas themselves.This work presents the design and prototyping of a deployable Fresnel Zone Plate antenna for CubeSats. The first model is a technical demonstrator, but it is also meant for a GNSS-Radio Occultations payload on a 6U CubeSat. Due to its characteristics and modularity it could be easily redesigned and modified to be used in communications, etc. at other frequency bands.

The Remote sensing and Interference detector with radiome-Try and vegetation Analysis (RITA) payload was selected in 2019 the 2nd GRSS Student Grand Challenge to fly onboard AlainSat-1, a 3U CubeSat developed at the National Space Science and Technology Center (NSSTC) in United Arab Emirates. RITA payload includes a passive Microwave Radiometer (MWR), a LoRa transceiver, and an hyper-spectral camera. The objective of the payload is to retrieve Earth Observation (EO) parameters such as: soil moisture, sea-ice thickness and concentration, among others. A Radio Frequency Interference (RFI) detection algorithm is also included to the payload to create interference maps in the received signals.

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.