Two‐Way Assessment of Ionospheric Maps Performance Over the Brazilian Region: Global Versus Regional Products

Satellite navigation based on the Global Navigation Satellite System can provide aircraft with more precise guidance and increase flight efficiency. However, severe space weather events can cause satellite navigation failure due to the dramatic increase in total electron content and irregularities in the ionosphere. Consequently, ground navigation has to be used to replace satellite navigation, increasing aircraft separation standards and reducing airspace capacity. As a result, numerous flights may be delayed or even canceled, incurring significant financial losses. The occurrence peak of space weather events generally coincides with the 11‐year‐cycle solar maximum, and 2025 is expected to be the upcoming solar maximum. The Greater Bay Area (GBA), located in the equatorial ionization anomaly region of China, is particularly vulnerable to space weather impacts. To explore the effects of satellite navigation failure on flight operation, we conduct this looking‐forward study and propose solution methods from the standpoint of Air Traffic Management, by simulating satellite navigation failure scenarios. Based on the projected flight volume in 2025 related to the GBA airports, simulation results show that the economic costs can be tens of millions of Euros, which is dependent on the duration of satellite navigation failure and the time interval of ground navigation‐based landing. We believe that this study can be a benchmark for evaluating the potential economic effects of forthcoming space weather on flight operations.

Section: Discussionmentioning

confidence: 99%

Forward‐Looking Study of Solar Maximum Impact in 2025: Effects of Satellite Navigation Failure on Aviation Network Operation in the Greater Bay Area, China

Xue,

Yang,

Liu

et al. 2023

“…The most usual ionospheric products for GNSS applications, that is, GIMs provided by IGS, UQRG, and CODG, are also included in the positioning analysis. The UQRG and CODG products are selected because they have shown some of the best results in terms of GNSS positioning (Jerez et al., 2023).…”

Section: Methodsmentioning

confidence: 99%

PPP at Low Latitudes With Ionospheric Model Exclusively Based on Single Frequency GNSS Measurements

Christovam,

Prol,

Jerez

et al. 2023

Self Cite

Single frequency users of the Global Navigation Satellite System (GNSS) should correct the ionospheric delay to obtain positioning solutions. A valuable source of ionospheric delay corrections is the global ionospheric models (GIMs) of Vertical Total Electron Content. The accuracy of GIMs is therefore important to improve the positioning accuracy. One of the main issues that affects the GIM performance, especially at low latitude regions, is the high sensitivity of the global positioning system (GPS) L2 frequency to ionospheric scintillation. As an attempt to overcome this issue, in this work, we study the capabilities of using only GPS L1 frequency to compute ionospheric corrections in form of regional ionospheric maps. The performance of the new ionospheric model is evaluated by means of single frequency precise point positioning, comparing the positioning results against the correction using dual‐frequency GPS signals, as well as compared to the corrections provided by GIMs produced by the international GNSS service. As a result, the positioning performance using single frequency model presented similar accuracy to the dual frequency models and, at the same time, provided less observations affected by ionospheric scintillations. These results demonstrate the feasibility of using single frequency GNSS data to develop ionospheric models and to improve the positioning over low latitudes.

“…Ionospheric delay is one of the main error sources during GNSS positioning, especially for single‐frequency users. The STEC should be calculated accurately from the ionospheric model to obtain a more reliable positioning result (Jerez et al., 2023; Rovira‐Garcia, 2020). On the other hand, the positioning performance can reflect the precision of ionospheric models.…”

Section: Methods Descriptionsmentioning

confidence: 99%

A Comparison of a GNSS‐GIM and the IRI‐2020 Model Over China Under Different Ionospheric Conditions

He,

Li,

Zhang

et al. 2023

The ionosphere is a crucial factor affecting Global Navigation Satellite System positioning. The Global Ionosphere Map (GIM) or the International Reference Ionosphere (IRI) model can be used for regional ionospheric correction. Since southern China is located near the electron density equatorial anomaly, this study evaluates the performance of the Wuhan University GIM (WHU‐GIM) and the IRI‐2020 from 2008 to 2020 over the China region. The comparison indicates that the Total Electron Content (TEC) from IRI‐2020 is lower than that from WHU‐GIM overall, the discrepancy is more obvious in high solar conditions and low‐latitude regions. The differential Slant TEC (dSTEC) during a phase‐arc with about 0.1 TECU accuracy derived from Global Positioning System (GPS) observations is used for model validation, the results show that the accuracies of WHU‐GIM and IRI‐2020 are 3.14 and 4.57 TECU, respectively. The dSTEC error is larger at low latitudes and decreases with increasing latitude. GPS‐derived TEC is taken for reference to evaluate the model reliability. Results show that both models can reproduce the diurnal TEC variations, but IRI‐2020 is more influenced by geomagnetic activities. The TEC correction percentage for IRI‐2020 is about 60%–80% under different ionospheric conditions, while for WHU‐GIM is 80%–90%. The Single‐Frequency Precise Point Positioning is performed with the ionosphere delay corrected by the two models, respectively. The positioning errors show that using IRI‐2020 has a lower accuracy, and the TEC discrepancy of the IRI‐2020 can cause a large bias in the up direction, especially at low‐latitude regions.