Robust Low-Cost Navigation Solutions for Service Robotics

L'abstract è presente nell'allegato / the abstract is in the attachmen

Assessment of positioning performances in Italy from GPS, BDS and GLONASS constellations

The use of multiple GNSS constellations has been beneficiary to positioning performances and reliability in recent times, especially in low cost mass-market setups. Along with GPS and GLONASS, GALILEO and BDS are the other two constellations aiming for global coverage. With ample research demonstrating the benefits of GALILEO in the European region, there has been a lack of study to demonstrate the performance of BDS in Europe, especially with mass-market GNSS receivers. This study makes a comparison of the performances between the combined GPS-GLONASS and GPS-BDS constellations in Europe with such receivers. Static open sky and kinematic urban environment tests are performed with two GNSS receivers as master and rover at short baselines and the RTK and double differenced post processed solutions are analyzed. The pros and cons of both the constellation choices is demonstrated in terms of fixed solution accuracies, percentage of false fixes, time to first fix for RTK and float solution accuracies for post processed measurements. Centimeter level accuracy is achieved in both constellations for static positioning with GPS-BDS combination having a slightly better performance in comparable conditions and smaller intervals. GPS-GLONASS performed slightly better for longer intervals due to the current inconsistent availability of BDS satellites. Even if the static tests have shown a better performance of GPS-BDS combination, the kinematic results show that there are no significant differences between the two tested configurations. Keywords: GNSS, BDS, GLONASS, NRTK positioning, Accurac

GNSS Anti-Spoofing Defense Based on Cooperative Positioning

Radio navigation is of utmost importance in several application fields. Nowadays, many civil and professional applications massively rely on the Global Navigation Satellite System (GNSS) and related technologies to accurately estimate position and time. Existing GNSS-based systems are threatened by malicious attacks among which spoofing and meaconing constitute severe challenges to the receiver. Several of such GNSS systems constitute mass market applications and devices, and a threat to the GNSS receiver could have cascading effects at application levels and for interconnected systems. Networked GNSS receivers are in general ubiquitous because any receiver embedded in a complex system such as a smart device or smart connected cars can exploit network connectivity. This novel generation of valuable-performance GNSS receivers are prone both to standard RF spoofing attacks and to cyber-attacks conceived to hijack complex network based services such as DGNSS-based cooperative positioning. By means of a set of experimental tests, this paper highlights possible metrics to be checked to identify malicious attacks to the positioning and navigation systems in mass market connected devices. The network-based exchange of GNSS data such as GNSS raw measurements recently disclosed in Android smart devices is conceived in this work to offer the possibility to compare or combine such metrics to better identifies spoofing and meaconing attacks

Efficacy and safety of baricitinib or ravulizumab in adult patients with severe COVID-19 (TACTIC-R): a randomised, parallel-arm, open-label, phase 4 trial

Background From early in the COVID-19 pandemic, evidence suggested a role for cytokine dysregulation and complement activation in severe disease. In the TACTIC-R trial, we evaluated the efficacy and safety of baricitinib, an inhibitor of Janus kinase 1 (JAK1) and JAK2, and ravulizumab, a monoclonal inhibitor of complement C5 activation, as an adjunct to standard of care for the treatment of adult patients hospitalised with COVID-19. Methods TACTIC-R was a phase 4, randomised, parallel-arm, open-label platform trial that was undertaken in the UK with urgent public health designation to assess the potential of repurposing immunosuppressants for the treatment of severe COVID-19, stratified by a risk score. Adult participants (aged ≥18 years) were enrolled from 22 hospitals across the UK. Patients with a risk score indicating a 40% risk of admission to an intensive care unit or death were randomly assigned 1:1:1 to standard of care alone, standard of care with baricitinib, or standard of care with ravulizumab. The composite primary outcome was the time from randomisation to incidence (up to and including day 14) of the first event of death, invasive mechanical ventilation, extracorporeal membrane oxygenation, cardiovascular organ support, or renal failure. The primary interim analysis was triggered when 125 patient datasets were available up to day 14 in each study group and we included in the analysis all participants who were randomly assigned. The trial was registered on ClinicalTrials.gov (NCT04390464). Findings Between May 8, 2020, and May 7, 2021, 417 participants were recruited and randomly assigned to standard of care alone (145 patients), baricitinib (137 patients), or ravulizumab (135 patients). Only 54 (39%) of 137 patients in the baricitinib group received the maximum 14-day course, whereas 132 (98%) of 135 patients in the ravulizumab group received the intended dose. The trial was stopped after the primary interim analysis on grounds of futility. The estimated hazard ratio (HR) for reaching the composite primary endpoint was 1·11 (95% CI 0·62–1·99) for patients on baricitinib compared with standard of care alone, and 1·53 (0·88–2·67) for ravulizumab compared with standard of care alone. 45 serious adverse events (21 deaths) were reported in the standard-of-care group, 57 (24 deaths) in the baricitinib group, and 60 (18 deaths) in the ravulizumab group. Interpretation Neither baricitinib nor ravulizumab, as administered in this study, was effective in reducing disease severity in patients selected for severe COVID-19. Safety was similar between treatments and standard of care. The short period of dosing with baricitinib might explain the discrepancy between our findings and those of other trials. The therapeutic potential of targeting complement C5 activation product C5a, rather than the cleavage of C5, warrants further evaluation

On the Cooperative Ranging between Android Smartphones Sharing Raw GNSS Measurements

The combination of ubiquitous network infrastructure and the high density of powerful, interconnected mobile devices in urban areas is driving the rise of smart cities. In parallel, the availability of ultra-low cost embedded Global Navigation Satellite System (GNSS) has enabled several affordable Location Based Services (LBS). New chipsets supporting dual frequency and multi-constellation GNSS signals are reducing the gap between high grade and mass market device performances. Among these devices, Android smartphones represent valuable and affordable tools for many LBS in the early advent of Intelligent Transportation Systems and smart vehicular navigation. Mobile networks natively provide a multiplicity of connected devices, thus enabling a family of applications demanding for a communication channel among GNSS receivers. This paper experimentally validates a collaborative technique based on the exchange of raw GNSS measurements to retrieve the relative range between Android smartphones. Additionally, a framework for the exchange of data between smartphones is provided, allowing the application of such a computationally-efficient ranging methodology in a network of low cost mobile devices within a smart city framework

A Proof-of-concept of Cooperative DGNSS for UAV/UGV Navigation

Service robotics is becoming a reality in many aspects of daily life due to the successful merger of several enabling technologies from the fields of Information and Communication Technologies. The growing availability of mass market products is also driving innovation towards automation in several civil and scientific areas. Specific applications such as precision farming, surveying, rescue operations and remote exploration can benefit from such modern and affordable robots, thus helping humans in work-related or daily life. To support such a new generation of service robots and vehicles, navigation capabilities play a fundamental role in mission planning and on-field activities. In parallel, recent developments of ultra-low cost embedded Global Navigation Satellite System (GNSS), such as in Android™ smartphones has enabled affordable Location Based Services (LBS) applications and provided an impetus to research into low cost navigation solutions. Modern smartphones come with an advantage of having a ubiquitous network infrastructure with ease of developing interconnected applications and integrated proprioceptive and exteroceptive sensors. Within the framework of precision agriculture promoted by the Politecnico di Torino Interdepartmental Centre for Service Robotics, this work investigates a low-cost navigation strategy for an Unmanned Ground Vehicle (UGV) – Unmanned Aerial Vehicle (UAV) paradigm exploiting a collaborative ranging technique based on Differential GNSS (DGNSS) approach applied on raw measurements exchanged between Android™ smartphones

A Controlled-Environment Quality Assessment of Android GNSS Raw Measurements

Raw Global Navigation Satellite System (GNSS) measurements have been available since 2016 in select Android smartphones. The availability of such observations allows smartphones users, in principle, to significantly improve the quality of GNSS-based positioning by applying customized and advanced positioning algorithms. However, the quality of such measurements is poor, mainly because of the low quality of smartphone hardware components and the nonideal environment in which phones are typically used. To overcome this problem and to separate the contribution of the hardware components and signal quality, dedicated test campaigns were carried out in a real environment and in a controlled-environment anechoic chamber using several different Android models. In addition, signal-processing techniques aimed at increasing the accuracy and precision of the solution were employed. Results show that the quality of the data captured in the anechoic chamber was significantly better than in real conditions. Furthermore, such analysis allows to underline certain phenomena in smartphones, such as the duty cycle, and to test the validity of anechoic environments for Android raw measurements

Assessment of the Vulnerability to Spoofing Attacks of GNSS Receivers Integrated in Consumer Devices

In this paper, we investigate the effects of spoofing attacks on the mass-market positioning and navigation units integrated in modern day Android™ smartphones. In order to operate spoofing in a real environment, we signed and implemented a portable, configurable, low-cost GPS spoofer exploiting a software-defined radio (SDR) implementation and a low-cost front-end. Such a tool has been exploited to set up a test campaign trying to mislead the Position, Velocity and Time computation of different Android™ smartphones. The effects of such simplistic spoofing attack on the smartphone GNSS has been assessed observing raw measurements and the evaluated positions and time. The main findings of this work showed that modern Android™ devices have a remarkable resilience to simplistic spoofing attacks, highlighting in parallel further potential weaknesses to be protected by means of practical defence mechanisms and countermeasures to spoofing

Fast Deformation Detection with mass market GNSS time differential observations and use of baseline constraints

Global Navigation Satellite Systems (GNSS) technology has been a consistent alternative to monitor and detect structural deformation using geodetic receivers. The role of low cost GNSS receivers have been explored in recent years and this study proposes the use of two such receivers as master and rover respectively to detect fast deformations. Single differenced observations of C/A code and L1 GPS carrier phase are differenced in time to obtain positions and velocities of a rover receiver and the performance of these observations in deformation detection is seen. Additional constraints of baseline between the master and rover are shown to improve the performance with successful detection of de?ections through rover velocity readings. Continuing previous research, another door for the use of low cost receivers to reliably detect deformations is opened and the real time use of such methodology can be explored

Hate Crime during the COVID-19 Pandemic: A Qualitative Study of the Experiences of an Ethnically Diverse University Student Population

The COVID-19 pandemic coincided with a rise in reports of hate crime against East and Southeast Asian minorities. Political rhetoric blaming China for causing the pandemic was tantamount to a ‘permission to hate’, making COVID-19 a catalyst of hate crime against Chinese people which also fuelled overt prejudice against other ethnic minorities. Researching experiences of hate offences in an ethnically diverse university student population in the United Kingdom during COVID-19, this qualitative study found that actual reported cases potentially underestimate the problem of hate crime. Analysing data from semi-structured interviews, we argue that a focus on reported cases alone risks obscuring the full extent of pandemic-related harassment and the insidious nature of hate crimes more generally. Minority ethnic interview participants lived with varying degrees of fear of victimisation, even if they were not personally subjected to any actual incidents during the pandemic. Accounts of pre-pandemic experiences, along with vicarious experiences involving victims with similar characteristics as interview participants, confirm the status of hate crime as a ‘message crime’. Third-party bystander accounts involving the victimisation of others whose identity research participants did not share afford additional insights into the nature and extent of pandemic-related hate