Attitude Determination via GNSS Carrier Phase and Inertial Aiding

Attitude Determination (AD) constitutes an important navigation component for vehicles that require orientation information, such as spacecraft or ships. Global Navigation Satellite Systems (GNSS) enable resolving the orientation of a vehicle in a precise and absolute manner, by employing a setup of multiple GNSS antennas rigidly mounted onboard the tracked vehicle. To achieve high-precision attitude estimation based on GNSS, the use of carrier phase observations becomes indispensable, with the consequent added complexity of resolving the integer ambiguities. The use of inertial aiding has been extensively exploited for AD, since it enables tracking fast rotation variations and bridging short periods of GNSS outage. In this work, the fusion of inertial and GNSS information is exploited within the recursive Bayesian estimation framework, applying an Error State Kalman Filter (ESKF). Unlike common Kalman Filters, ESKF tracks the error or variations in the state estimate, posing meaningful advantages for AD. On the one hand, ESKF represents attitude using a minimal state representation, in form of rotation vector, avoiding attitude constraints and singularity risks on the covariance matrix estimates. On the other hand, second-order products on the derivation of the Jacobian matrices can be neglected, since the error-state operates always close to zero. This work details the procedure of recursively estimating the attitude based on the fusion of GNSS and inertial sensing. The GNSS attitude model is parametrized in terms of quaternion rotation, and the overall three-steps AD procedure (float estimation, ambiguity resolution and solution fixing) is presented. The method performance is assessed on a Monte Carlo simulation, where different noise levels, number of satellites and baseline lengths are tested. The results show that the inertial aiding, along with a constrained attitude model for the float estimation, significantly improve the performance of attitude determination compared to classical unaided baseline tracking

The V-SHARK high contrast imager at LBT

In the framework of the SHARK project the visible channel is a novel instrument synergic to the NIR channel and exploiting the performances of the LBT XAO at visible wavelengths. The status of the project is presented together with the design study of this innovative instrument optimized for high contrast imaging by means of high frame rate. Its expected results will be presented comparing the simulations with the real data of the "Forerunner" experiment taken at 630nm

Early biomarkers of altered renal function and orthostatic intolerance during 10-day bedrest

Exposure to actual or simulated microgravity results in alterations of renal function, fluid redistribution, and bone loss, which is coupled to a rise of urinary calcium excretion. We provided evidence that high calcium delivery to the collecting duct reduces local Aquaporin 2 (AQP2)-mediated water reabsorption under vasopressin action, thus limiting the maximal urinary concentration to reduce calcium saturation. To investigate early renal adaptation into simulated microgravity, we investigated the effects of 10 days of strict bedrest in 10 healthy volunteers. We report here that 10 days of inactivity are associated with a transient, significant decrease (day 5) in vasopressin (copeptin) paralleled by a decrease in AQP2 excretion, consistent with an increased central volume to the heart, resulting in reduced water reabsorption. Moreover, bedrest caused a significant increase in calciuria secondary to bone demineralization paralleled by a decrease in PTH. Urinary osteopontin, a glycoprotein exerting a protective effect on stone formation, was significantly reduced during bedrest. Moreover, a significant increase in adrenomedullin (day 5), a peptide with vasodepressor properties, was observed at day 5, which may contribute to the known reduced orthostatic capacity post-bedrest. We conclude that renal function is altered in simulated microgravity and is associated with an early increase in the risk of stone formation and reduced orthostatic capacity post-bedrest within a few days of inactivity

Recurrence of COVID-19 after recovery: a case report from Italy

Since the beginning of SARS-CoV-2 pandemic, Italy is one of the most affected country in the world. Here we describe a case of recurrence of COVID-19 in a 48-year- old apparently cured patient in Italy, at the beginning of May, 2020. The possibility of a reactivation of COVID-19 poses a major public health concern, since it could significantly contribute to the spread of the virus in the population. Further investigations on convalescent cases are needed to address this issue

The first light of the Solar Activity MOF Monitor Telescope (SAMM)

SAMM (Solar Activity MOF Monitor) is a ground based robotic instrument that has been developed to study and constantly monitor the magnetic activity of the Sun, focusing on Active Regions (ARs). These regions are characterized by complex magnetic structures that may result in explosive events usually associated with large amount of particle and matter ejections in the space environment. When interacting with the Earth magnetosphere they can represent a threat for our infrastructures both in space (satellites, navigation systems) and on the ground (power plants and electrical grids). Based on Sodium (Na) and Potassium (K) magneto optical filters (MOFs), SAMM provides a “tomographic” view of the magnetic structures delivering high cadence magnetograms and dopplergrams at different heights of the solar atmosphere thus providing a unique dataset with the aim to push forward the current space weather forecasting capabilities. Being able to forecast these events enough in advance (even few hours) is a fundamental task to put in place mitigation strategies to reduce the potential catastrophic impact on vital infrastructures on earth. In this scenario the SAMM observatory has been realized to be a “node” that can be replicated in a world-wide network with the aim to give a continuous coverage of the Sun situation. This project has been initially funded by the Italian Ministry of Economic Development (MiSE) in 2015 through a soft loan grant and its development and operation is carried on within a scientific collaboration between the INAF – Rome and Naples Astronomical Observatories and the Italian small enterprise (SME) Avalon Instruments. After three years of development, SAMM is in the commissioning phase. In this paper we are presenting a final instrument description along with the first light images

Novel PHB/Olive mill wastewater residue composite based film: Thermal, mechanical and degradation properties

In the last few years there has been a growing interest in the use of bio-based and biodegradable plastics, made of renewable resources. A common biodegradable polymer, microbial-derived, is Poly-3-hydroxybutiric acid (PHB). However, PHB homopolymer exhibits a high crystalline structure, which leads to mechanical properties that are not fully compatible with a number of production processes. An interesting approach is blending PHB with other compounds in order to improve its physical properties and reducing the production costs of the finished products. The olive mill wastewater (OMW) is an organic-rich residual that arises from the production and refinery of olive oil, mainly composed by aromatic and aliphatic compounds, proteins, sugars and lipids. In addition, some of these compounds exhibit a higher biotoxicity, which makes OMW not suitable for those applications in which biodegradability is required. Nevertheless, OMW is an inexpensive and abundant source of fine chemicals such as polyphenols, leading, after their extraction, to OMW matrix residuals (OMWR) rich in lignin-cellulose. In this work, OMWR was used as a natural filler for the production of PHB based films. PHB/OMWR composite samples were characterized by chemical, thermal, morphological and mechanical analyses. Furthermore, the degradation profiles, in different environments, were evaluated with the aim to develop materials suitable for agriculture and food packaging applications