In this work we present a method for detecting the activity of the ionosphere (TEC) and we illustrate the signature of the solar activity on the vertical total electron content VTEC, during 02 to 08 November 2015, using GPS measurements obtained from two stations in Morocco, the first one in Marrakech at Observatory of Oukaimeden OUCA (31°12′23.3″ N 7°51′58.8″ W), the second in Rabat, Rabt (33.9981°N;353.1457°E, geographic).

This paper focuses on the performance analysis of ionosphere monitoring using the measurements from a BeiDou Continuously Operating Reference Stations (CORS) network. Combined pseudo-range and carrier phase observations are used to estimate total electron content (TEC) and the hardware delay deviation is also computed. Using the observations from five BeiDou CORS in China, the TEC monitoring results were obtained from each station and compared with GPS monitoring results and also those from the Global Ionosphere Maps (GIM) model. Numerical computation shows that the BeiDou system has the ability to precisely detect the TEC diurnal variation trend on each station. The Residual Mean Square (RMS) difference between the BeiDou and the GIM model at a higher latitude station is about four TEC Units (TECU), while the RMS difference between the GPS and the GIM is about three TECU; at a lower latitude station this difference increases to six TECU for BeiDou and four TECU for the Global Positioning System (GPS); at the lowest latitude station in this study, the differences for both systems are about six TECU.

The total electron content (TEC) is an important parameters in the Earth's ionosphere, related to various space weather and solar activities. However, understanding of the complex ionospheric environments is still a challenge due to the lack of direct observations, particularly in the polar areas, e.g., Antarctica. Now the Global Positioning System (GPS) can be used to retrieve total electron content (TEC) from dual-frequency observations. The continuous GPS observations in Antarctica provide a good opportunity to investigate ionospheric climatology. In this paper, the long-term variations and fluctuations of TEC over Antarctica are investigated from CODE global ionospheric maps (GIM) with a resolution of 2.5°×5° every two hours since 1998. The analysis shows significant seasonal and secular variations in the GPS TEC. Furthermore, the effects of TEC fluctuations are discussed.

Ambiguity resolution is essential for precise range determination. As it is difficult to process, a good ionospheric model is essential to get unambiguous results or to reduce time to solve the ambiguities. In this paper, a developed model to determine the differential ionospheric error to sub-centimetre accuracy is described. As a function of elevation angle and TEC, the model is applicable at any location and only requires a single frequency receiver provided the TEC over the reference station is known. It has been evaluated using real GPS measurements at spaced stations in Glasgow (UK) and Stirling (UK), where the results showed good correlation. It was found that the variance ratio and reference variance of the ambiguity resolution rate and the quality of the differential positioning solution are improved. Significant improvements of more than 50% have also been found by correcting the differential ionospheric delay in the measurements for the estimated positions.

Extensive ionospheric scintillation and Total Electron Content (TEC) data were collected by the Institute of Engineering Surveying and Space Geodesy (IESSG) in Northern Europe during years of great impact of the solar maximum on GNSS users (2001–2003). The ionospheric TEC is responsible for range errors due to its time delay effect on transionospheric signals. Electron density irregularities in the ionosphere, occurring frequently during these years, are responsible for (phase and amplitude) fluctuations on GNSS signals, known as ionospheric scintillation. Since June 2001 four GPS Ionospheric Scintillation and TEC Monitor receivers (the NovAtel/AJ Systems GSV4004) have been deployed at stations in the UK and Norway, forming a Northern European network, covering geographic latitudes from 53° to 70° N approximately. These receivers compute and record GPS phase and amplitude scintillation parameters, as well as TEC and TEC variations. The project involved setting up the network and developing automated archiving and data analysis strategies, aiming to study the impact of scintillation on DGPS and EGNOS users, and on different GPS receiver technologies. In order to characterise scintillation and TEC variations over Northern Europe, as well as investigate correlation with geomagnetic activity, long-term statistical analyses were also produced. This paper summarises our findings, providing an overview of the potential implications of ionospheric scintillation for the GNSS user in Northern Europe.

Comunicamos el caso de un paciente que sufría distimia. Fue sometido a un tratamiento de ECT con éxito y fue medicado con nefazodona y midazolam. Comparando el EEG y la duración de la crisis motora en los periodos con y sin midazolam, no se registraron diferencias significativas, pero las dosis de tiopental y de succinilcolina se tuvieron que aumentar de manera notable después de la interrupción del midazolam (P < 0,05; ANOVA). Este caso indica una interacción farmacodinámica sustancial entre nefazodona, midazolam, tiopental y succinilcolina.