Characteristics of ionospheric scintillation climatology over Indian low-latitude region during the 24th solar maximum period

The amplitude and phase of L-band satellite signals are fluctuated randomly due to small scale electron density irregularity structures in the ionosphere which result in fleeting variations, known as 'ionospheric scintillations'. The Global Navigation Satellite System(GNSS) is a profound remote sensing tool to monitor, model and forecast the ionospheric weather conditions. In this paper, the GNSS amplitude scintillation data has been analyzed during the year 2013 at Bengaluru(12.9°N, 77.59°E) and Lucknow(26.8467°N, 80.9462°E) stations to reinforce climatology of ionospheric scintillation over Indian low-latitude region. The probability of scintillation occurrence and their variations over equatorial and Equatorial Ionization Anomaly(EIA) regions in India are analyzed during various geomagnetic quiet and disturbed days, months and seasons. The annual occurrence of amplitude scintillations are mapped with the function of local time. It is observed from the experimental results that the probability of scintillations occurrences is higher over EIA region than over the equatorial region. The probability of scintillations is higher during March equinox and December solstice, and lowest during June solstice.Distribution of scintillations is intense during post-sunset period. The maximum percentage of scintillation occurrences at the two stations are recorded in November. Moreover, the highest percentage of scintillation occurrences took place on storm day(March 17, 2013) at the two stations. This work would be helpful for understanding the features of GNSS amplitude scintillations over Southern and Northern Indian regions. Moreover, these kinds of investigations are helpful for developing new algorithms to nowcast and forecast ionospheric scintillations over Indian Sub-continent.

An improved peak side lobe reduction method for linear array antenna for military applications

Purpose-The purpose of this paper is to improve energy efficiency and further reduction of side lobe level the algorithm proposed is firework algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).Design/methodology/approach-The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.One of the most important properties of antenna array is beam pattern.A directional main lobe with low side lobe level(SLL)of the beam pattern will reduce the interference and enhance the quality of communication.The classical methods for reducing the side lobe level are differential evolution algorithm and PSO algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).It is demonstrated that the FA plainly beats the SPSO and the CPSO in both enhancement exactness and combination speed.The results convey that the side lobe level is reduced to
34.78dB and fill rate is increased to 78.53.Findings-Samples including 16-element LAAs are conducted to verify the optimization performances of the SLL reductions.Simulation results show that the SLLs can be effectively reduced by FA.Moreover,compared with other benchmark algorithms,fireworks has a better performance in terms of the accuracy,the convergence rate and the stability.Research limitations/implications-With the use of algorithms radiation is prone to noise one way or other.Even with any optimizations we cannot expect radiation to be ideal.Power dissipation or electro magnetic interference is bound to happen,but the use of optimization algorithms tries to reduce them to the extent that is possible.Practical implications-16-element linear antenna array is available with latest versions of Matlab.Social implications-The latest technologies and emerging developments in the field of communication and with exponential growth in users the capacity of communication system has bottlenecks.The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology which is to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.Originality/value-By using FA,the fill rate is increased to 78.53 and the side lobe level is reduced to 35dB,when compared with the bench mark algorithms.