*hendy SANTOSA^1,2、Yasuhide Hobara^1,3,4、Takuo Tsuda^1,3,4、Satya Srinivas⁴ (1.Department of Computer and Network Engineering, The University of Electro-Communications, Tokyo, Japan、2.Department of Electrical Engineering, Bengkulu University, Bengkulu, Indonesia、3.Earth Environment Research Station, The University of Electro-Communications, Tokyo, Japan、4.Center for Space Science and Radio Engineering, The University of Electro-Communications, Tokyo, Japan)