Vertical Sounding Research Articles

Geoelectric assessment of groundwater aquifers at RONIZ area, Southeastern SHIRAZ, IRAN

In order to manage groundwater resources and presenting appropriate management strategies, the value of acquiring Knowledge of groundwater flow and volume estimate is obvious. Particularly, since in IRAN due to its climate conditions (dry and semi-dry), water resources for agriculture is strongly linked to groundwater resources. In this regard, vertical sounding with Schlumberger array is the most common and most useful geophysical method in groundwater exploration studies. In this study, to evaluate the Roniz aquifer located in 160 km south East of Shiraz, 97 electerical sounding was implanted. Field data in view of the log wells and area geological data was processed and interpretated by IPI2Win software and with its help the depth and Subsurface layers thickness in area was determined. Acquired Results from interpretation of sounding curves in the region shows four to five main layers, Which contains a dry alluvial layer average with electric resistance of 200 Ω-m and an average thickness of 20–60 m, Sandstone layer with electrical resistance of 340 Ω-m and an average thickness of between 10 and 15 m, Marl layer with electrical resistance 20–41 Ω-m and thickness of 20–30 m, Aquifer (lime) layer with the electrical resistance of 0.4–6 Ω m and a thickness of between 6 and 8 m, and lime stone floor from a depth of about 150 m down. In addition that with the help of these soundings, 13 wells were designed and are being exploited.

Observations of ionospheric disturbances via U-shaped traces on ionograms

The ionospheric vertical sounding i s a basic technique for studying the Earth’s ionosphere. Taking into account the fact that conditions for propagation of radio waves depend on the operating frequency , d iagnostics of the ionosphere is performed using digital ionosondes that measure the delay s of decameter radio signal s of different frequencies. An ionogram is a display of the data produced by an ionosonde. It is a graph of the virtual reflection height of the ionosphere (actually , time between transmission and reception of a radio signal ) versus sounding frequency. Vertical and near-vertical ionograms provide the major share of information about the space-temporal structure of the ionospheric plasma above the ionosonde . Of particular interest is investigating dynamic processes from the series of ionograms taken once each minute. Studying seismic ionospheric effects by minute ionograms can be highly informative. It is known that the parameters of the ionospheric layers can significantly vary both before and after an earthquake , and such deviations are detectable from ionosonde data. Recent observations show that the effects from an earthquake can occur at large distances from the epicenter. For instance , s oundings in the Irkutsk region detected the anomalies that occurred several dozens of minutes after the main shock of the 11 .03. 201 1 earthquake in Japan. At the initial phase, the anomaly was recorded as a multicusp structure i n the ionogram, which was probably related to the multiple layers of the ionosphere. Th is structure was interpreted by iterative reconstruction of the electron density profile in a one-dimensional approximation (stratified ionosphere) , and the interperation was published . At the next p hase, the ionograms showed a U-shaped structure with a specific multiple reflection. Multipath propagation is usually associated with additional off-vertical ray paths, which are caused by traveling ionospheric disturbance s (TIDs) . In this regard, it is appropriate to use a 2D model of electron density , depending on both the vertical and horizontal coordinates. In our study , geometric optics approximation was used to simulat e vertical ionograms under the conditions of strong horizontal gradients of electron density. The study results show that d ifferent positions of the U-shaped structure with respect to the main tra ce of the ionogram can be obtained for a single TID . Specific ray paths forming the additional trac es of the ionogram are described . D epending on the TID location , the U-shaped structure can occur with or without a specific multipath reflection.

Effects in the Ionosphere after the Chilean Earthquake on February 27, 2010, According to Data of Ground-based Ionosondes

The paper analyzes the measurement data of the critical frequency (foF2) of the regular ionospheric F2-layer at a number of ground based stations of the vertical sounding of the ionosphere in order to detect disturbances in the ionosphere that followed the earthquake with a magnitude of M = 8.8. The earthquake occurred in Chile on February 27, 2010 at 0634 UT at an epicentral distance of 335 km from its capital city of Santiago. It was found that at significant distances (over 5000 km) from the earthquake epicenter under a quiet geomagnetic conditions, wave disturbances are observed in the behavior of foF2, exceeding approximately two standard deviations from the background level for three hours, with the maximum relative deviation of 20%. The analysis shows that the characteristics of disturbances in the ionosphere correspond in time to the arrival of a packet of acoustic-gravity waves excited in the atmosphere at the time of the seismic shock.

Using Project Loon Superpressure Balloon Observations to Investigate the Inertial Peak in the Intrinsic Wind Spectrum in the Midlatitude Stratosphere

AbstractLocation information from superpressure balloons flown by Project Loon provide an unprecedented opportunity to analyze wind fields in the midlatitude stratosphere. Horizontal velocity spectra from the balloons' quasi‐intrinsic frame of reference show clear evidence of a persistent peak in the intrinsic wind spectrum around the inertial frequency. In the Southern Hemisphere midlatitudes, peak‐to‐peak amplitudes of horizontal velocity perturbations (on the order of 20 m/s) are larger than those seen in previous superpressure balloon campaigns in polar regions and similar to those observed in vertical soundings in the midlatitudes. A rotary spectral analysis shows that near‐circular anticyclonic rotation of horizontal wind perturbations around the inertial frequency dominate at most times and locations. The strongest anticyclonic rotation is more common in balloon flight segments with weak zonal winds and during the austral summer. Flight segments with strong eastward zonal velocities during austral winter and spring are more likely to have mixed cyclonic and anticyclonic power around the inertial frequency. These results confirm previous model and radiosonde observations of the peak in horizontal kinetic energy at the inertial frequency and demonstrate they are associated with increased anticyclonic wave power indicative of near‐inertial oscillations or inertia‐gravity waves. Flight segments with mixed cyclonic and anticyclonic power around the inertial frequency display a continuum of wave power from planetary to gravity wave scales. These results help explain the divergence of actual and modeled balloon trajectories in previous studies and provide a baseline against which reanalysis or meteorological model realizations of the intrinsic velocity field can be assessed.

Ionospheric parameters in the European sector during the magnetic storm of August 25–26, 2018

Variations of ionospheric parameters Total Electron Content (TEC) by GNSS, critical frequency (foF2) by vertical sounding and electron density (Ne) by low-altitude satellite were studied at high, mid and low latitudes of the European sector during the magnetic storm of August 25–26, 2018. During the main phase of the storm the ionospheric F2-layer was under the positive disturbance at mid and low latitudes. Then the transition from the positive to negative ΔfoF2 values occurred at all latitudes. The recovery phase was characterized by negative ionospheric disturbance at all latitudes. This is due to the decrease of thermospheric O/N2 ratio during the recovery phase of the storm. The intense Es layers screened the reflections from the F2-layer on August 26th at high and at low latitudes but at different times. Some blackouts occurred due to the high absorption level at high latitudes. In general, foF2 and TEC data were highly correlated. The major Ne changes were at the low latitudes. In general, Ne data confirmed the ionospheric dynamics revealed with foF2 and TEC.

Possibilities of the usage of the total electron content in a low-latitude zone

Last years, the small quantity of ionosondes at low latitudes could not give a sufficient picture of behavior of the ionosphere in these areas. Now, reception of experimental data, their analysis and detection of total electron content (TEC) variations at low latitudes are an actual problem. When moving from describing the state of the ionosphere using vertical sounding parameters to describing using TEC, it is important to identify similarities and differences in their behavior in order to assess the possibilities of using TEC. This paper carries out research on four ways of TEC usage in low-latitude zone: (1) research of climatological peculiarities of the TEC behavior, (2) validation of up-to-date TEC models, (3) foF2 calculation according to observational TEC, and (4) peculiarities of TEC behavior during geomagnetic disturbances. Results for station Hainan show the following. 1. In addition to previous investigation it is shown, that the empirical global and local models of TEC provide the values close to observational ones, however climatological features of TEC behavior described by various models may still differ from each other and from the experimental data showing in this case TEC maxima of diurnal variation in the afternoons, seasonal variations in March and October, some slight winter anomaly. 2. In contrast to previous investigation it is shown that the closest to the experimental values of TEC are provided by the IRI-Plas model, while this model overestimates values, and the model NeQuick underestimates values compared to the observational ones. 3. For the first time, the ionospheric equivalent slab thickness τ, which plays the role of the coefficient of proportionality between TEC and NmF2, was compared for the IRI, IRI-Plas, NeQuick models with the experimental median τ(med) and it was shown, that the usage of observational TEC data and τ(med) for calculation of critical frequencies foF2 allows improving correspondence with experimental data by 1.2–2 times compared to the models. 4. Comparison of foF2 and TEC behavior has a particular importance during disturbances. Using the example of 15 strong magnetic storms (Dst < −50 nT), it was shown that, despite its global nature, the details of the TEC response strongly depend on the region. So, the peculiarities of δTEC in comparison with the mid-latitude region are the predominance of the positive phase, and a smaller value of response. The synchronism of variations δTEC and δfoF2 was very high, although there are cases of mismatch. Using the median τ(med) allows determining foF2 during disturbances and filling data gaps.

Fast Ionospheric Dynamics during a Substorm from Vertical and Oblique Sounding Data

Synchronous studies have been conducted on the high-latitude ionosonde at Sodankyula station and the low-latitude ionosonde in Cyprus Island, as well as on two radio paths (the Sodankyula–Gor’kovskaya subauroral and Cyprus–Gor’kovskaya midlatitude paths) during the intense substorm of February 14, 2011. Fast processes (within 5–10 min) have been identified according to vertical sounding at Sodankyula station: sporadic Es layers with an inclined track, multilayer tracks in Es layers, anomalous spreadF, well-expressed layers in diffuse F formations, rapid changes in the peak observed frequencies in the Es layer, and multijump Es reflections of signals. During the substorm, the sporadic Es layers and diffusion in the ionospheric F2 layer are the most stable. The data from vertical sounding at Sodankyula station and oblique sounding on the Sodankyula–Gor’kovskaya track have been found to agree qualitatively. The distance between Sodankyula station and the reflection point of the Sodankyula–Gor’kovskaya path is 400 km in the southern direction. Thus, the ionospheric processes during the substorm are qualitatively close, within 400 km. However, there is a difference between the vertical and oblique sounding data and the data from oblique sounding on the Gor’kovskaya–Cyprus track with a reflection point near the city of Chișinău.

Modeling of the Ionospheric Critical Frequency of the F2 layer over Asia based on Modified Temporal‐Spatial Reconstruction

AbstractA model based on modified temporal‐spatial reconstruction is proposed to improve the accuracy of predicting the monthly median ionospheric critical frequency of the F2 layer. This model has three new characteristics. (1) The solar activity parameters of the 10.7‐cm solar radio flux and sunspot number are together introduced into temporal reconstruction. (2) Both the geomagnetic dip and its modified value are chosen as features of the geographical spatial variation for spatial reconstruction. (3) Harmonic functions are used to represent the ionospheric critical frequency of the F2 layer, which reflects seasonal and solar cycle variations. Furthermore, combining the least squares fitting regression for these characteristics with harmonic analysis, a valid model can be established from vertical sounding data spread across three ionospheric regions (high, middle, and low latitudes in Asia). Statistical results reveal that the ionospheric critical frequency of the F2 layer calculated by the proposed model is consistent with the trend of the monthly median observations. The average root‐mean‐square error is only 0.70 MHz (corresponding to relative error 11.30%), reflecting that our model outperforms the International Reference Ionosphere model with International Union of Radio Science and Consultative Committee on International Radio (CCIR) coefficients. Moreover, the proposed method has great potential in terms of providing higher prediction accuracy for ionospheric parameters on the global scale.

Deterministic Variability of the Ionosphere on the Eve of Strong (M ≥ 6) Earthquakes in the Regions of Greece and Italy According to Long-Term Measurements Data

Abstract—Specific features of the variation in the electron concentration in the ionosphere in front of strong (M ≥ 6) earthquakes in the most seismically active areas of Europe, Greece and Italy, are considered on the basis of long-term measurements. Vertical sounding data (variations of the critical frequency foF2) are analyzed to cover long periods of time before the GPS/GLONASS era, and variations of the vertical total electronic content are also analyzed with the advent of global navigation satellite systems receivers in the considered regions. This analysis is based on the results of previous publications that revealed features of ionospheric precursors such as self-similarity, which is expressed in the exceptional stability of electron concentration variation as dependence on the local time. Its graphic representation is called the ionospheric precursor mask. This stability, which is defined as deterministic variability, is confirmed by the multiyear measurement data presented in this work. One new result involves the regional features of the ionospheric precursor mask found for Italy, where the mask for earthquakes in central Italy (within a radius of 300 km north of Rome) and the mask for earthquakes in southern Italy (within a radius of 300 km south of Rome) differ in phase. A possible explanation of the observed regional features is proposed.

Statistical analysis and modelling of sporadic E layer over Europe

This paper describes a study of the daily and yearly variability of one of the main characteristics of sporadic E layers (Es), the critical frequency (foEs). Our analysis is based on ionograms recorded by GIRO network ionosondes. The study estimates the spatial and temporal variability of the Es layer parameters and generates their statistics at different seasons and phases of the solar cycle. In turn, the statistics of the Es layer parameters can provide an assessment of the capability of the HF propagation forecasting. Further, maps of the distribution of Es layer critical frequency are produced. This paper implements the “cloud” model of Es layer in HF propagation model (Northern Ionosphere Model & Ray Tracing, NIM-RT) that can accurately reproduce many features observed in experimental measurements. Within this framework, a number of vertical sounding ionograms with the presence of Es layer are simulated based on the NIM-RT software.

СТРУКТУРА ПОЛЯ СКОРОСТИ ЭКВАТОРИАЛЬНОГО ТЕЧЕНИЯ ЛОМОНОСОВА ПО ДАННЫМ ИЗМЕРЕНИЙ ВЕСНОЙ 2014 И ОСЕНЬЮ 2015 гг.

Two examples of measurements of oceanic equatorial currents in the Atlantic using an shipborne acoustic Doppler current profiler SADCP on meridional sections across the equator in spring 2014 at 23°W and autumn 2015 at 34°W are considered. The relevant data of some previous observations in this region are also used for comparison. The methods for studying the Lomonosov Current using ship profiling and moorings are discussed. According to the results of profiling with a two-minute averaging of the source data of the section of September 27, 2015, a structure of the two-dimensional section of the high-resolution velocity field is presented, which is characterized by small-scale fragmentary stratification, which was previously detected only from one-dimensional data of vertical soundings of velocity and other parameters of the ocean environment. Using the example of comparing this detailed section with the versions for other time averages (15 and 60 min) differences in the estimates of parameters of the velocity field due to the averaging are specified. Using the example of vertical profiles through the core of the Lomonosov Undercurrent (EUC) in the springs of 2002 and 2014 and winters of 2002 and 1971 at the locations close to 23°W, the stability of the annual cycle of fluctuations of the intensity of currents in the core and the position of the core in a multiyear aspect is illustrated. The agreement of our results with other previously published data is shown. The main parameters of the velocity field over the equatorial section on April 17, 2014 indicate a high probability of the outcropping of the easterly flow on the surface. Similar episodes of outcropping in 2002 within the PIRATA program together with corresponding intervals of changing the direction of the zonal component of wind speed derived from the Era Interim reanalysis from westward to eastward are demonstrated. A similar correlation with the wind is assumed to occur on April 17, 2014.

Observed and Calculated Ionograms of Oblique Ionospheric Sounding on HF Radio Paths During a Magnetic Storm of September 7–8, 2017

Ionograms of the oblique ionospheric sounding radio paths Cyprus—Lovozero and Lovozero—Gor’kovskaya (near St. Petersburg) are analyzed using magnetometers and riometers. The behavior of the maximum observed frequencies (MOF) of the F2 and Es layers during a magnetic storm of September 7–8, 2017 is considered. The storm has a specific, not classical form and can be divided into two parts, namely, the first and the second storms. The main results are as follows. 1) The manifestation of the first storm is accompanied by a significant increase in absorption and frequent absence of signals on the paths. The second storm is characterized by increased values of MOF-Es and the presence of signals. 2) The signals on the midlatitude Cyprus—Lovozero path propagate both as 1F2, 2F2, and 3F2 modes and as 2Es and 3Es modes. 3) On the subpolar Lovozero—Gor’kovskaya path, during the disturbance, the signals mainly propagate via reflection from the sporadic Es layer of very high intensity. 4) Modeling of the propagation of HF radio waves using the IRI-2016 model adapted to the vertical sounding data made it possible to match the model ionograms with the real oblique sounding ionograms, including the cases of presence of the M and N modes, as well as triplets, in both quiet and disturbed conditions, which is a new result.

Modeling the HF Ray Trajectories and Vertical and Oblique Ionograms in the Artificially Disturbed Ionosphere Based on Radiotomographic Data

This paper presents the results of numerical simulation of the propagation of HF radio waves in the artificially disturbed ionosphere during launch of the Tsyklon-3 carrier rocket from the Plesetsk cosmodrome on December 18, 1991, and an industrial high-power explosion with a magnitude of M = 2.4 on the Kola Peninsula on April 8, 1990. A specially developed software package in Python programming language allows three-dimensional modeling of ray trajectories in the geometric optics approximation by solving a bicharacteristic system for the eikonal equation. The geomagnetic field is specified according to the IGRF model, and the ionospheric electron density distribution is specified according to radio tomography data. The ionogram modeling is performed using a three-dimensional shooting method based on the Nelder—Mead simplex minimization. It is shown that the artificial ionospheric irregularities that arise during the periods of the considered events are quasi-wave perturbations that have a significant effect on the ray trajectories of HF radio waves and ionograms of vertical and oblique sounding. This effect manifests itself in the form of characteristic peculiarities of ray trajectories with multiple reflections from the local maxima of the electron density and additional traces on ionograms caused by the passage of traveling ionospheric disturbances above the sounding system.

Alternate Mapping Correlated k-Distribution Method for Infrared Radiative Transfer Forward Simulation

The alternate mapping correlated k-distribution (AMCKD) method is studied and applied to satellite simulations. To evaluate the accuracy of AMCKD, the simulated brightness temperatures at the top of the atmosphere are compared with line-by-line radiative transfer model (LBLRTM) or the observed data which are from Advanced Himawari Imager (AHI) on board the Himawari-8, as well as Medium Resolution Spectral Imager (MERSI) on board the Fengyun-3D. The result of AMCKD is also compared with the algorithm of Radiative Transfer for the Television Observation Satellite Operational Vertical Sounder (RTTOV). Under the standard atmospheric profiles, the absolute errors of AMCKD in all longwave channels of AHI and MERSI are bounded by 0.44K compared to the benchmark results of LBLRTM, which are more accurate than those of RTTOV. In the most cases, the error of AMCKD is smaller than the NEDT at ST, while the error of RTTOV is larger than the instrument noise equivalent temperature (NEDT) at scene temperature (ST). Under real atmospheric profile conditions, the errors of AMCKD increase, because the input data from ERA-Interim reanalysis dataause bias in the satellite remote sensing results. In the most considered cases, the accuracy of AMCKD is higher than RTTOV, while the efficiency of AMCKD is slightly slower than RTTOV.

A description of the Elevation sensitive Oblique Incidence Sounder Experiment (ELOISE)

The Elevation sensitive Oblique Incidence Sounder Experiment (ELOISE) was an extensive experiment undertaken by the Defence Science and Technology (DST) Group that focused on collecting ionospheric sensor data from multiple overlapping ionospheric paths in the Australian region in order to improve understanding of the characteristics of ionospheric variability and its effect on HF radio propagation. The experiment ran from July to October 2015 and included a period of three weeks of increased sample density and three days of dedicated over-the-horizon (OTH) radar operations. It was anticipated that ELOISE would sample a wide range of environmental conditions and present an opportunity to characterise periods of “normal variability” and periods of “exceptional variability” in the ionosphere.This report is a general description of the aims of this experiment and the types of data collected. Particular interest focused on observing and measuring variability in ionospheric electron density gradients and their effect on oblique HF propagation. To this end, ELOISE established a pair of two dimensional HF receiver arrays to directly measure the oblique angle of arrival (AoA) on many overlapping oblique paths. ELOISE also established a dense sub-network of spatially separated quasi-vertical incidence soundings in the vicinity of Alice Springs in central Australia. This enabled a comparison of gradients observed in a dense network of vertical sounders with gradient effects observed in oblique propagation passing overhead. Several additional ionospheric observing systems were also used to give complementary pictures of the fine scale characteristics of ionospheric variability in the region. Plain Language SummaryThis paper is an overview of the 2015 Elevation sensitive Oblique Incidence Sounder Experiment (ELOISE), an experiment designed to observe and characterise mid-latitude ionospheric disturbances in the Australian region and understand their impact on high frequency (HF) signal propagation.ELOISE involved the simultaneous operation of a large collection of ionospheric sounders enabling ionospheric variability to be characterised on a finely sampled large scale.Particular efforts were made to provide direct high fidelity measurements of the angle of arrival (AoA) on many oblique HF propagation paths. These direct AoA measurements imply horizontal electron density gradients that can be compared to ionospheric gradients estimated from conventional models of the ionosphere derived from the spatial network of sounder sites.The size and scope of the experiment are detailed in this paper and some preliminary results are presented.

Mobile and direct-prospecting methods: the possibility of their application for areas of geothermal water accumulation searching and mapping

The results of application of the frequency-resonance technology of remote sensing data processing and geoelectric methods of forming a short-pulsed electromagnetic field (FSPEF) and vertical electric-resonance sounding (VERS) within prospecting areas in Turkey, Slovakia, Mongolia, Nevada (USA), England and Ukraine are analyzed. Anomalous zones of “thermal water” type have been found within all survey areas. The drilled geothermal wells in all surveyed areas in Turkey fell into the contours of the anomalous zones of “thermal water” type. In some areas, a detailed vertical sounding by VERS method and vertical scanning of satellite data were carried out; the depths and thicknesses of aquifers were determined, and the water temperatures in them were estimated. For a more confident search for zones of accumulation of fresh (mineralized, geothermal) water, it is necessary to process remote sensing data at a scale of 1:10 000 and larger. The results of frequency-resonance processing of satellite images can be verified and refined by FSPEF and VERS methods. The joint use of these methods allows accelerating and optimizing the geothermal sources prospecting and exploration of. Approved mobile geophysical methods are recommended for practical use during prospecting and exploration of geothermal waters within known zones of geothermal sources development.

A Novel Ionospheric Sounding Network Based on Complete Complementary Code and Its Application.

In this paper, complete complementary code (CCC) sequences are applied to a High Frequency (HF) ionospheric sounding network. Ionosondes distributed at multiple locations use the mutually orthogonal CCC sequences to conduct vertical soundings synchronously. At the same time, thanks to the omnidirectional antennas, every station can receive the oblique echoes transmitted from the others. Due to the orthogonality between the code sequences, both vertical and oblique ionograms can be simultaneously obtained and completely separated. Through this method, the sounding efficiency can be enhanced, and the inversion difficulty can be reduced. Further, by using the data assimilation method, vertical and oblique sounding results can be combined to obtain a wide range of regional ionospheric characteristics. To verify the performance of this kind of sounding network, validation experiments are implemented to demonstrate that vertical and oblique ionograms can be obtained independently at the same time and inverted separately and that the maps of foF2 parameters obtained by using the data assimilation method provide more details than single vertical or oblique sounding.

OFDM signal with BPSK modulated subcarriers for multi-carrier ionospheric sounding

Paper presents the developed algorithm for multi-carrier simultaneous vertical ionospheric sounding by OFDM signal with BPSK modulation of subcarriers. There is presented a mathematical model, numerical and simulation modeling with the use of USRP platform. Research findings proved the fundamental feasibility of using orthogonal subcarriers for simultaneous sounding of channels over a wide band.

Measurement of coordinates of sources of radio emission at high frequencies goniometric and goniometric and range-metering by methods

Coordinates of sources of a radio emission of range of high frequencies using an on-off system azimuth and meridian direction finders are measured by a goniometric method. In the bearing posts active arrays of vertical vibrators and synchronized coherent radio receivers with frequency conversion are used. For minimization of amplitude and phase not identities preliminary calibration of channels of the receiver at frequencies of the taken the bearings signals is executed. By results of measurements average quadratic deviations of coordinates of sources of a radio emission of type of radio stations of meteo-information of airfield networks of the Russian Federation and the neighboring countries, standard frequency stations and time, transmitters of telecode and continuous messages are investigated. The analysis of dependences of achievable accuracy figures of measurements on the space provision of positions of direction finders, lengths of routes and also fluctuations of electro-physical parameters and space distribution of the ionized layers of the atmosphere leading to changes of beam trajectories of distribution and abnormal errors of measurements of the directions of arrival of radio waves to different season and day is carried out. It is shown that in the lower part of range of high frequencies the measurement error of coordinates of sources of a radio emission a goniometric system makes 4.7 %, and in process of approach of frequency to the upper bound of range this indicator increases by 1.2 times. By results of bearing of signals in one point of space and measurements of height of layers of the atmosphere with use of the station of vertical sounding coordinates of sources of a radio emission are determined by a goniometric and range-metering method. Measurements of coordinates of objects by a goniometric and range-metering method can be executed with average quadratic deviation of 11-13 % of range.

Calculation of Navigation Corrections for a Single-Frequency GNSS Receiver Based on Satellite Radio Occultation Data

A methodology has been developed to construct SBAS ionospheric grid based on the data from ionosphere radio occultation monitoring systems such as COSMIC. This methodology facilitates calculation of vertical delay of GNSS signals on frequency L1 for any geographical location. The corrections are used by a single-frequency receiver for improving the accuracy of position estimation in solving the navigation problem. Using the combination of ionosphere model and the data from radio occultation monitoring systems, it is possible to form real-time corrections on a global scale, and to make their short-term forecasts. The proposed method testing results showed good conformance with the data from vertical sounding stations, and the magnitudes of vertical delays of signal on frequency L1, represented by EGNOS system as differential corrections.