The GNSS NavAer INCT Project Overview and Main Results

Abstract

Air navigation is increasingly dependent on the use of Global Navigation Satellite Systems (GNSS). It allows the determination of the aircraft's position in all phases of the flight and brings many advantages. Although GNSS navigation results in gains, the radio signals from these systems are strongly influenced by the ionospheric environment. It introduces errors that can affect the accuracy, integrity, availability and continuity requirements established by the International Civil Aviation Organization (ICAO). The ionospheric layer has different behaviors depending on the latitude, time of day, season of the year, geomagnetic activity and solar cycle. Since Brazil is located in a region of low latitudes, it experiences a series of unique challenges when compared to regions of mid-latitudes. For this reason, the application of GNSS-based technologies in aviation over the Brazilian territory requires an in-depth assessment of the ionosphere effects. Therefore, the Instituto Nacional de Ciência e Tecnologia (INCT) named GNSS Technology for Supporting Air Navigation was formed in 2017 to better assess the ionosphere impacts and assist government agencies and companies in the development of safe air navigation procedures over Brazil in a near future. This paper presents the most relevant advances achieved so far within this multidisciplinary project that involves Brazilian research centers and universities.

Stepping Into an Equatorial Plasma Bubble With a Swarm Overfly

“…ISMRs data are provided by: (a) formerly CIGALA/CALIBRA network managed by Universidade Estadual Paulista (UNESP) (Bougard et al., 2011, 2013; Vani et al., 2017), now called “GNSS NavAer network” (Monico et al., 2022); (b) Low‐Latitude Ionospheric Sensor Network (LISN) (Valladares & Chau, 2012); (c) “Brazilian Studies and Monitoring of Space Weather” program (EMBRACE) of the Brazilian National Institute for Space Research (INPE); and (d) Dutch Royal Netherlands Meteorological Institute (KNMI). ISMR data from KNMI are part of the data collections available through the eSWua data portal (http://eswua.ingv.it) managed by “Istituto Nazionale di Geofisica e Vulcanologia” (Upper atmosphere physics and radiopropagation Working Group, 2020).…”

“…ISMRs data are provided by: (a) formerly CIGALA/CALIBRA network managed by Universidade Estadual Paulista (UNESP) (Bougard et al, 2011(Bougard et al, , 2013Vani et al, 2017), now called "GNSS NavAer network" (Monico et al, 2022) IMSRs are multi-frequency multi-constellation receivers with low-noise OCXO oscillators able to provide, from 50 Hz sampling of the GNSS signal post-correlation in-phase and quadrature components, the amplitude scintillation index S4 over a 1-min interval and for every satellite-receiver pair (Bougard et al, 2011). An elevation mask of 15° is applied to reduce the impact of the multipath, which may mimic amplitude scintillation.…”

A Retrospective of Global Navigation Satellite System Ionospheric Irregularities Monitoring Networks in Brazil

“…The GNSS-NavAer (https://inct-gnss-navaer.fct.unesp.br/) is a follow-on of the CIGALA/CALIBRA network, which is located inside the Brazilian territory (for more details see Monico et al 2022). New GNSS receivers, Septentrio PolaRx5S, were deployed in some new sites and most of the older receivers PolaRxS-PRO were replaced.…”

“…Due to its low cost, along with the possibility of training students in the areas of science, telecommunications and programming, this kind of platform has a promising future, particularly for the development of networks in technical schools and universities. As mentioned in Monico et al (2022), lowcost monitors have been used by undergraduate students from IFSP in Brazil, to introduce them to IoT and computer science concepts, allowing the students to develop their skills in these areas. Another interesting example of this kind of low-cost of monitors is the work of Fagundes et al (2021) where a system similar to those described in this section was developed dedicated to SNR-based GNSS reflectometry.…”

“…The pioneering L-band scintillation monitoring network in Brazil is no longer in activity but was the Cornell Scintillation Monitor (CSM). The GNSS scintillation monitor networks currently acquiring data in Brazil are the Low-Latitude Ionospheric Sensor Network (LISN), the CIGALA/CALIBRA, the ICEA/DECEA and the GNSS NavAer INCT project (Monico et al 2022). Additionally, the network of geodetic receivers called RBMC/IBGE provides GNSS observables, which allow the estimation of the TEC and consequently the ROTI.…”