SibNet — Siberian Global Navigation Satellite System Network: Current state

In 2011, ISTP SB RAS began to deploy a routinely operating network of receivers of global navigation satellite system signals. To date, eight permanent and one temporal sites in the Siberian region are operating on a regular basis. These nine sites are equipped with 12 receivers. We use nine multi-frequency multi-system receivers of Javad manufacturer, and three specialized receivers NovAtel GPStation-6 designed to measure ionospheric phase and amplitude scintillations. The deployed network allows a wide range of ionospheric studies as well as studies of the navigation system positioning quality under various heliogeophysical conditions. This article presents general information about the network, its technical characteristics, and current state, as well as the main research problems that can be solved using data from the network

The use of GPS-arrays in detecting shock-acoustic waves generated during rocket launchings

This paper is concerned with the form and dynamics of shock-acoustic waves (SAW) generated during rocket launchings. We have developed a method for determining SAW parameters (including angular characteristics of the wave vector, and the SAW phase velocity, as well as the direction towards the source) using GPS-arrays whose elements can be chosen out of a large set of GPS-stations of the global GPS network. The application of the method is illustrated by a case study of ionospheric effects from launchings of launch vehicles (LV) Proton and Space Shuttle from space-launch complexes Baikonur and Kennedy Space Center (KSC) in 1998 and 1999 (a total of five launchings). The study revealed that, in spite of a difference of LV characteristics, the ionospheric response for all launchings had the character of an N - wave corresponding to the form of a shock wave, regardless of the disturbance source (rocket launchings, industrial explosions). The SAW period T is 270--360 s, and the amplitude exceeds the standard deviation of TEC background fluctuations in this range of periods under quiet and moderate geomagnetic conditions by factors of 2 to 5 as a minimum. The angle of elevation of the SAW wave vector varies from 30 degree to 60 degree, and the SAW phase velocity (900-1200 m/s) approaches the sound velocity at heights of the ionospheric F-region maximum.Comment: EmTeX-386, 23 pages, 6 figure

Traveling wave packets of total electron content disturbances as deduced from global GPS network data

We identified a new class of mid-latitude medium-scale traveling ionospheric disturbances (MS TIDs), viz. traveling wave packets (TWPs) of total electron content (TEC) disturbances. For the first time, the morphology of TWPs is presented for 105 days. Using the technique of GPS interferometry of TIDs we carried out a detailed analysis of the spatial-temporal properties of TWPs by considering an example of the most conspicuous manifestation of TWPs on October 18, 2001 over California, USA. The velocity and direction of TWPs correspond to those of mid-latitude MS TIDs obtained previously from analyzing the phase characteristics of HF radio signals as well as signals from geostationary satellites and discrete cosmic radio sources.Comment: LaTeX2.09, 28 pages, 9 figure

Boron nanotubes and their properties: semiempirical investigation

The problem of formation possibility nanotubular structures is actively discussed now. We considered the fragments of single-wall boron nanotubes (n, n) (n=4, 5, 6, 9, 11, 12). Calculations were carried out by IB-CCC method [Litinskii A.O., et al., Journal of physical chemistry - 1995 - V. 69., N° 1., P. 189. (In Russian)]. The analysis of band-gap showed that all of them are semiconductors. Energy of deformation decreases with increase of the diameter of B-tubes (n, n). We considered the B-nanotubes (n, 0) (n=4, 5, 6, 8, 12). In this case deformation energy is increases with increase of the diameter of tubes (n, 0). Calculations of boron tube (6, 6) which contained various defects of structure were obtained by the semiempirical MNDO scheme. We research substitution imperfection of B atom by atom C, ions C+, C-. We found out substitution energy of defects and its energy level. We studied the B-tube with atomic vacancy and determined the energy of defect activation and the relative portion of vacancies.At the moment active search of new surface structures capable of effective adsorption of different gases is being carried out. We have investigated an binding opportunity between the H, F, O, Cl atoms and the outer surface of B-nanotube (6,6) and have studied the mechanism of this process. The calculations are carried out with the use of quantum chemical MNDO scheme. Regular hydrogenation of boron nanotubes was investigated. We can confirm that generation of gas-phase hydrogen composite materials based on boron nanotube is possible

Complex analysis of the ionospheric response to operation of “Progress” cargo spacecraft according to the data of GNSS receivers in Baikal region

As part of the Plasma–Progress and Radar–Progress space experiments conducted from 2006 to 2014, effects of the Progress spacecraft engines on the ionosphere have been studied using data from Global Navigation Satellite System (GNSS) receivers. 72 experiments have been carried out. All these experiments were based on data from the International GNSS Service (IGS) to record ionospheric plasma irregularities caused by engine operation. 35 experiments used data from the ISTP SB RAS network SibNet. The analysis of the spatio-temporal structure of total electron content (TEC) variations has shown that the problem of identifying the TEC response to engine operation is complicated by a number of factors: 1) the engine effect on ionospheric plasma is strongly localized in space and has a relatively low intensity; 2) a small number of satellite—receiver radio rays due to the limited number of GNSS stations, particularly before 2013; 3) a potential TEC response is masked with background ionospheric disturbances of various intensities. However, TEC responses are identified with certainty when a satellite—receiver radio ray crosses a disturbed region within minutes after the impact. TEC responses have been registered in 7 experiments (10 % of cases). The amplitude of ionospheric response (0.3–0.16 TECU) exceeded the background TEC variations (~0.25 TECU) several times. The TEC data indicate that the ionospheric irregularity lifetime is from 4 to 10 minutes. According to the estimates we made, the transverse size of irregularities is from 12 to 30 km

First results of registering ionospheric disturbances obtained with SibNet network of GNSS receivers in active space experiments

Global and regional networks of GNSS receivers have been successfully used for geophysical research for many years; the number of continuous GNSS stations in the world is steadily growing. The article presents the first results of the use of a new regional network of GNSS stations (SibNet) in active space experiments. The Institute of Solar-Terrestrial Physics of Siberian Branch of Russian Academy of Sciences (ISTP SB RAS) has established this network in the South Baikal region. We describe in detail SibNet, characteristics of receivers in use, parameters of antennas and methods of their installation. We also present the general structure of observation site and the plot of coverage of the receiver operating zone at 50–55° latitudes by radio paths. It is shown that the selected location of receivers allows us to detect ionospheric irregularities of various scales. The purpose of the active space experiments was to reveal and record parameters of the ionospheric irregularities caused by effects from jet streams of Progress cargo spacecraft. The mapping technique enabled us to identify weak, vertically localized ionospheric irregularities and associate them with the Progress spacecraft engine impact. Thus, it has been shown that SibNet deployed in the Southern Baikal region is an effective instrument for monitoring ionospheric conditions

WTEC: A new index to estimate the intensity of ionospheric disturbances

We propose a new index, WTEC, to estimate the level of ionospheric disturbances from Global Navigation Satellite Systems (GNSS) data. The index is calculated based on dual-frequency phase measurements from single GNSS receiver. An index value exhibits the average intensity of the total electron content (TEC) variations over specified periods in the restricted area above a single GNSS receiver and reflects, mainly, the level of Wave activity in TEC (WTEC). The index has been shown to well detect the ionospheric disturbances of different origin and can be used as an efficient indicator for the ionospheric state. We believe that the proposed index has a great potential for ionospheric research: from studying isolated events at a local point to analyzing long data series and creating global maps of ionospheric disturbances. Keywords: Ionosphere, TEC, Ionospheric disturbance index, GNS

Dynamics of the level of total electron content disturbance at high and middle latitudes according to GPS data

We study the level of total electron content (TEC) disturbance in ionospheric mid-latitude and high-latitude regions, which occurred during 2013. TEC behavior is calculated using data from two GPS stations: MOND (Mondy) and NRIL (Norilsk). TEC variations are estimated from dual-frequency phase measurements for all radio signal paths. We analyze the TEC variations in two time ranges: 10 and 40 min. These ranges correspond to medium- and large-scale ionospheric disturbances respectively. The TEC disturbance level is characterized using a special index WTEC. It allows us to receive multi-day continuous series of average TEC variation intensity. We reveal that at high latitudes WTEC variations correlate well with AE ones. The correlation between WTEC and Dst variations is much lower. The minimum level of TEC disturbance is independent of the season in the Arctic region; diurnal WTEC variations are more pronounced for medium-scale ionospheric disturbances than for large-scale ones. At mid-latitudes, the WTEC variation concurs with Dst and Kp variations only during strong magnetic storms. The minimum level of TEC disturbance is higher in summer than in winter. At middle latitudes, the sunset terminator generates gravity waves. In the Arctic region, terminator-induced waves are not observed