• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1048-1054
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• 2012

This paper presents a Carrier phase fault detection (FD) method for GPS RTK (Global Positioning System Real Time Kinematic) in dynamic environment. There are various error sources in dynamic environment and these errors decrease the reliability of FD results. Due to the reason, Carrier phase measurements are separated into satellite induced signal, user induced signal and other remaining errors. Especially the user-induced signal is computed by user dynamic which is estimated by time-differenced Carrier phase (TDCP) and Doppler shift. TDCP makes it possible to avoid integer ambiguity resolution. Computer simulation is conducted to verify the suggested method. By applying impulse, step and ramp faults, the FD performance is analyzed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.7
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• pp.17-28
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• 2000

A novel and efficient approach for the numerical solution of time-dependent coupled-wave equations, which are frequently used for the modeling of DFB(Distributed Feedback), DBR(Distributed Bragg Reflector), and FP(Fabry Perot) laser diodes, is proposed. In this approach, the coupled wave equations are split into two sets of equations. One of two sets of equations contains only the phase factors and the other contains only the coupling terms. The separate equations are solved exactly in their split form successively. This new numerical scheme, which we call the SS-TDM(Split-Step Time Domain Model), is found to require an order of magnitude smaller number of subsections to get accurate results than the previous methods while the computation time for each time step is comparable to the previous methods.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.206-209
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• 2005

It was investigated that two rods of aluminium can be welded by hot extru-pressure welding method with stepped welding dies, and that the welding pressure on the welding surface were analyzed by computer simulation according to the stepped shapes of welding dies. It was known by computer simulation that welding pressure on the welding section of rods welded using stepped welding dies without eccentricity is lowerer than the welding pressure of rods welded using stepped welding dies with eccentricity of welding surface, and that the welding pressure on the welding section of rods using eccentric-inclined stepped welding dies is higher than the welding pressure of rods using stepped welding dies without eccentricity. And it was known by experiments that two rods of aluminium can be welded on the end sections by hot pressure welding method using eccentric-inclined stepped welding dies without relative rotational movement of contacted aluminium rods needed for the purpose of friction heating and pressure.