Total electron content forecasting using artificial neural network

Space weather forecasting and its importance for the power and communication industry have inspired research related to TEC forecasting lately. Research has attempted to establish an empirical model approach for TEC prediction. In this paper, artificial neural networks (ANNs) have been applied in total electron content using GPS Ionospheric Scintillation and TEC Monitor (GISTM) data from UKM Station. The TEC prediction will be useful in improving the quality of current GNSS applications, such as in automobiles, road mapping, location-based advertising, personal navigation or logistics. Hence, a neural network model was designed with relevant features and customised parameters. Various types of input data and data representations from the ionospheric activity were used for the chosen network structure, which was a three-layer perceptron trained by feed forward back propagation method and tested on the chosen test data. We found that the optimum RMSE occurred with 10 nodes as the best NN for GISTM UKM station for the studied period with RMSE 1.3457 TECU. An analysis was made to compare the TEC from the measured TEC with neural network prediction and from IRI-corr model. The results showed that the NN model forecast the TEC values close to the measured TEC values with 9.96% of relative error. Thus, the forecasting of total electron content has the potential to be implemented successfully with larger data set from multi-centred environment

Modeling of magnetic loop antenna for an improved rockets/spacecraft communication operation

the magnetic loop antenna (MLA) is a compact hf antennas used transmitting signals within a fairly long distance. Its shape and size had metaphorsize from the usual analogue to a digital device-which is now used for experiments in space. In this paper, the resolution of the bearing angle errors of the antennas on a rocket or spacecraft was proposed to enhance improved application in signal transmission. A new concept was introduced -angular displacement theory which was used to mitigate fading in multipath propagation especially from Rocket or spacecraft orbit

Jumlah kandungan elektron sewaktu gangguan ionosfera bergerak di Parit Raja, Johor

Travelling ionospheric disturbance (TID) is a phenomenon caused by solar activity and TID strength varies by locations, especially in equatorial regions. This phenomenon affects the local total electron content (TEC), especially during the daytime. Because of this, research regarding augmenting TEC values during TID is done by comparing TEC values obtained from the IRI2001 and NeQuick models with IONEX data. By using Global Positioning System (GPS) data obtained from the Parit Raja station in the southern part of Malaysia (1º 52’ N, 103º 06’ E) as reference, research was conducted during geomagnetic quiet day as well as on the disturbed day. The occurrence of TID can clearly be seen when using the real TEC data from IONEX and WARAS. Result obtained from Parit Raja station shows a much more significant effect of TID occurrence on TEC than what was shown by IONEX data. However, the TEC values obtained from the IRI2001 and NeQuick models were influenced by the number of sunspots and were only applicable in geomagnetic quiet days. In order to obtain more accurate TEC values, it is necessary to ensure that TID condition is included in the IRI2001 and NeQuick model

Comparative study of TEC for GISTM stations in the Peninsular Malaysia region for the period of January 2011 to December 2012

Total Electron Content (TEC) is a fundamental and the most prevalent parameter that affects Global Positioning System (GPS) signals, leading to delays, poor signals or total loss of signals. The gradients in TEC are frequently associated with disturbance in the ionosphere which explains the space weather behavior and indirectly causes inefficient operations of ground and space based Global Navigation Satellite System (GNSS) applications. The role of TEC variability is constructive in space weather prediction as it allows GNSS users to minimize rangerate errors in achieving highly reliable measurements. This paper therefore presents an analysis of the diurnal and seasonal activity dependence of TEC using data obtained from the GPS Ionospheric Scintillation and TEC Monitor (GISTM) at two stations in Peninsular Malaysia which are located at the Langkawi National Observatory, Langkawi, LGKW (06_19’N, 99_51’E) and Universiti Kebangsaan Malaysia, UKM (02_55’N, 101_46’E). Data for the two years (2011 and 2012), were recorded using the NovAtel GSV 4004B GISTM model equipment. Further investigations on a few more stations in the coast of Peninsular Malaysia will strengthen and consolidate the findings of this study

Ionospheric correction and ambiguity resolution in DGPS with single frequency.

The free electron distributed in the atmospheric region known as the ionosphere produces a frequency dependent effect on the Global Positioning System (GPS) signals, a delay in the pseudorange and advance in the carrier phase. The ionospheric influence is one of the main problems in the real-time ambiguity resolution for the carrier phase GPS data in radio navigation. Real Time Kinematics (RTK) and Malaysian Active Station (MASS) data from JUPEM (Jabatan Ukur dan Pemetaan Malaysia) were used in this analysis. In this study, the effects of initial phase ambiguity at GPS and modeling of ionosphere on base components were researched. To overcome this problem, a correction ionospheric model was used. This correction model could be implemented in single frequency measurements with similar accuracy, which can be obtained from dual frequency

Correlation analysis of geomagnetic parameter with south atlantic anomaly region

South Atlantic Anomaly (SAA) region is describe as a region with weak Earth magnetic field. The method apply is power spectrum analysis. By applying the power spectrum analysis method, the value of spectral exponent, β is obtained. From the spectral exponent, β, the Hurst exponent can be determined. The research is conducted by studying the SAA region where comparisons is made between the middle latitude region and high latitude region. 2 active period has been research, 11 March 2011 and 29 May 2011 and 2 normal period has been studied, 9 March 2011 and 12 May 2011. The research conduct indicate the SAA region tend to be persistent and as the vertical field intensity and total field intensity increase, the region tend to have a mixture of antipersistent and persistent characteristic. The high latitude region in this research conduct indicate a tendency to be antipersistent. By conducting research on the SAA region, it can provide knowledge of the dynamics and conditions of our Earth. The SAA region is a region where it is exposed to energetic particles. Satellites passing through the SAA region are also vulnerable to danger. Therefore, the region conducted on the SAA region, can provide knowledge on the characteristics of the SAA region. Research on SAA may increase knowledge of the Earth’s magnetic field

Pengesanan gelembung plasma di dalam lapisan ionosfera menggunakan penerima GPS di Asia Tenggara

Lapisan ionosfera berhampiran kawasan khatulistiwa geomagnetik sering terdedah kepada gangguan pada waktu malam yang dikenali sebagai gelembung plasma (PBB). Kehadiran PBB boleh meningkatkan kadar perubahan amplitud dan fasa isyarat radio yang melaluinya dan memberi kesan terhadap sistem komunikasi dan navigasi. PBB biasanya terjadi secara berturutan dengan satu demi satu struktur muncul pada waktu senja. Walau bagaimanapun, waktu dan lokasi kemunculan PBB tidak dapat diramal kerana punca awal pembentukannya masih belum dikenal pasti. Walaupun pelbagai peralatan telah dibangunkan untuk mencerap PBB, namun setiap alat pengukuran dibataskan oleh resolusi ruang dan masa. Dalam kajian ini, struktur PBB dalam dua dimensi (2D) dicerap menggunakan rangkaian penerima GPS dengan kepadatan yang tinggi di Asia Tenggara. Data GPS dikumpulkan daripada 127 stesen penerima dengan jarak sekitar 30 hingga 120 km di antara satu sama lain. Jumlah kandungan elektron (TEC) diperoleh berdasarkan perbezaan antara dua isyarat yang dipancarkan oleh setiap satelit GPS. Kehadiran PBB dikesan menggunakan indeks kadar perubahan TEC (ROTI) bagi semua laluan isyarat dari satelit kepada penerima. Struktur 2D PBB diperoleh dengan mempuratakan data GPS ROTI ke dalam grid bersaiz 0.45o latitud × 0.45o longitud dan dipetakan pada ketinggian 300 km. Kajian kes pada malam 18 Mac 2011 menunjukkan kemunculan enam struktur PBB yang berturutan pada waktu senja apeks di sepanjang longitud 95oT hingga 120oT. Struktur-struktur PBB tersebut muncul dengan jarak di antara 100 hingga 550 km. Jarak kemunculan sturuktur PBB memainkan peranan penting dalam menentukan punca pembentukannya yang dipercayai berbentuk seakan gelombang

Relationship between students’ attitudes in space science with their achievements in the field

The purpose of this study is to identify the relationship between students’ attitude in space science with their achievement in the field. This study also examines students’ performance in space science. A total of 458 of secondary school students participated in this study. The questionnaire for this study was divided into two parts. The first part contains 9 items about students’ attitudes towards space science while the second part consists of 20 questions of general knowledge about space science. The findings show that students’ general knowledge about space science is at moderate level. The result also shows a significant relationship between students attitude with their achievement towards space science