Analisis Interferensi White Space Device terhadap Sistem Radio Navigasi Penerbangan pada Frekuensi 960 MHz

ABSTRAKPemerintah Indonesia mengalokasikan spektrum frekuensi 960-1164 MHZ untuk sistem komunikasi bergerak maupun untuk radio navigasi penerbangan. Penggunaan White Space Device (WSD) merupakan solusi keterbatasan spektrum, karena mampu mengidentifikasi dan memanfaatkan frekuensi yang tidak terpakai. Penelitian ini menyelidiki potensi interferensi yang terjadi pada koeksistensi sistem radio navigasi penerbangan serta perangkat WSD di pita 960 MHz. Penelitian menggunakan pendekatan matematis Minimum Coupling Loss (MCL) serta simulasi dengan Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT). Hasil penelitian menunjukkan bahwa level interferensi yang masih diperbolehkan berada di kisaran -81,589 dBm. Level ini tercapai dengan penggunaan jarak proteksi antar sistem sejauh 36 km. Penurunan daya pemancar WSD atau peningkatan gain RSBN sebesar 1 dBm dapat memperkecil jarak proteksi menjadi 30 km untuk mencapai probabilitas interferensi berturutturut 3,55% dan 3,6%.Kata kunci: white space devices, interferensi, radio navigasi penerbangan ABSTRACTThe Indonesian Government allocates the 960-1164 MHz spectrum for mobile communications and aeronautical radio navigation services. Cognitive radio is a technology which will enable the use of a limited spectrum optimally. Devices implemented with cognitive radio capability is referred as White Space Device (WSD) as they can identify and utilize idle channels. This paper investigates the interference potential between aeronautical radio navigation services and WSD as they co-exist in the 960 MHz spectrum using Minimum Coupling Loss (MCL) formulae and simulations using Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT). Results show that the permissible interference level is -81,589 dBm which is achievable if the two systems are separated by 36 km. Decreasing the WSD power level or increasing the RSBN gain by 1 dBm can decrease the protection distance between the two systems to 30 km to achieve an interference probability of 3,55% and 3,6%, respectively.Keywords: white space devices, interference, aeronautical radio navigation

Design of the Gating System for Production of Casting Blanks for Space Device Cases

Selection of an appropriate gating system for a consumable pattern is a long and time-consuming process that requires considerable effort. Advanced design technologies can be used to design the gating system and to simulate the casting process based on the design. Simulation and design of the gating system allow detection of types of defects in the casting at the development stage. Parametrical changing of the gating system 3D model and variation of its characteristics, and repeated simulation of cooling, crystallization and mold filling processes can provide high quality casting.

Single Event Transient Acquisition and Mapping for Space Device Characterization

It is necessary for space applications to evaluate the sensitivity of electronic devices to radiations. It was demonstrated that radiations can cause different types of effects to the devices and possibly damage them [1][2]. The interest in the effect of Single Event Transient (SET) has recently risen because of the increased ability of parasitic signals to propagate through advanced circuit with gate lengths shorter than 0.65 nm and to reach memory elements (in this case they become Single Event Upset (SEUs)). Analog devices are especially susceptible to perturbations by such events which can induce severe consequences, from simple artifacts up to the permanent fail of the device. This kinds of phenomena are very difficult to detect and to acquire, because they are not periodical. Furthermore, they can vary a lot depending on different parameters such as device technology and biasing. The main obstacle for the analysis is due to the maximum frequency of these signals, which is unknown. It is consequently difficult to set a correct sample frequency for the acquisition system. In this document a methodology to evaluate SETs in analog devices is presented. This method allows to acquire automatically these events and to easily study the sensitivity of the device by analyzing a “SETs cartography”. The advantages are different: it allows to easily acquire and analyze the SETs in an automatic way; the obtained results allow the user to accurately characterize the device under test; and, finally, the costs due to the implementation of the tests are lower than a classical analysis performed by a particle accelerator.