In the past, most of the drone was developed for military use, but recently it has been rapidly growing into industrial and civilian markets due to its potential to be applied to various fields. The industry of drones is attracting attention as a model of manufacturing and service convergence, creating synergy by converging with information technology and various services. However, the operating time of the commercial drone is limited to 15 ~ 20 minutes, so frequent wired charging is required. In order to overcome these drawbacks, this paper proposes a technology that can operate the drone by using wireless charging technology instead of cumbersome wired charging. The proposed technique can start wireless charging automatically when the drones land on the charging station. To maintain efficiency above 50%, regardless of the location of the charging station, a structure using two receiving coils has been proposed. In this case, two receiving coils can be applied to one or two receivers. In this paper, we analyze the advantages and disadvantages of these two cases and discuss the receiver structure and the method of maximizing chargeable area.

A resolution enhancement method for estimating the direction-of-arrival (DOA) of signals for coherent signals impinge on a uniform circular array is proposed. It increases the aperture size by virtually expanding the sensor spacing of original antenna array which is constructed by the steering matrix of the virtual array using the proper transformation matrix. Superior resolution is achieved with this method in comparison with the standard Deterministic Maximum Likelihood algorithm for coherent signals impinge on a uniform circular array.

The virtual expansion method of the array aperture was suggested in order to improve the direction-of-arrival (DOA) resolution of coherent signals. But the virtual expansion of a single array has an inherent limit to improve the DOA resolution capability due to spurious peaks at the spatial spectrum. To overcome the limit of this method, the spatial spectrum averaging method of the virtually expanded arrays is proposed. From the simulation results for coherent signals impinging on an uniform circular array, the perfect DOA resolution capability of 100% is achieved at the SNR of more than −5 dB by the Deterministic Maximum Likelihood (DML) algorithm including the proposed method. Meanwhile, the DOA resolution capability of the standard DML algorithm is less than 11% at the SNR of more than −5 dB.

This paper present the detailed design and the algorithm for forward link ACM(Adaptive Coding & Modulation) system to improve the link availability and system throughput in satellite communication services. To implement ACM system, the channel prediction and MODCOD decision methods is simulated. The channel prediction result shows that the 99% of predicted values in LMS(Least Mean Square) algorithm is within 3dB. Also this paper proposes the appropriate system architecture for ACM transmission.