• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.15 no.2
• /
• pp.195-206
• /
• 1997

By this time, in order to measure baseline in a few minutes, we must have used expensive dual frequency receiver. Recently, low-priced single frequency receiver have taken place of dual frequency receiver at short base-line by advancement in software development, improvements in geodetic survey receiver system. In this study, according to the observation time and measurement interval, we analyzed differences of each components of baseline by field experiment and we propose the criterion for the minor control point surveying by single frequency GPS receiver.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.81-86
• /
• 2004

GPS surveying is being applied in earnest in public and construction surveying field recently. However only large enterprise surveying companies have GPS equipments but almost of small companies don't have them because of that their financial status is always too poor to purchase the expensive equipments such as Dual frequency GPS receiver. This is caused by some misunderstanding that only Dual frequency GPS receiver can be used for Public surveying. In order to increase the use of Single frequency GPS receiver to achieve competitive power of small companies in future, we need to verify the applicability and recommend surveyors to use it.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.47-48
• /
• 2013

In order to evaluate the response of the grid-connected systems, Phase lock technology is widely used in power electronic devices to obtain the phase angle, amplitude, and frequency of the grid voltage because phase locked loop (PLL) algorithms are very important for grid synchronization and monitoring in the grid connected power electronic devices. This paper presents a performance evaluation in tracking grid angular frequency through single phase synchronization techniques which are an enhanced PLL (EPLL), second-order generalized integrator-PLL (SOGI-PLL), and second-order generalized integrator-frequency locked loop (SOGI-FLL). These techniques are properly analyzed through several steps to get the best technique which can track the frequency accurately and smoothly.

• Korean Journal of Geomatics
• /
• v.4 no.2
• /
• pp.47-52
• /
• 2004

We can process and compute the position, velocity and time by satellite signals of GPS. The signals are used to compute positioning of three dimensions and timing offset of the receiver clock when we can track the tour satellite signals at least. One of the specified aims is to use less expensive single frequency code/carrier phase GPS receivers, which are typically around half the price of dual frequency receivers. In the study, the author analyzed the accuracy and applicability of frequence linear combination using triangulation points evaluated distance limitation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.2
• /
• pp.157-162
• /
• 2006

In this paper, power supply for ozone generating system is explained. Output voltage and frequency are controlled by phase displacement control of single phase inverter using ATmega128. The values of desired output voltage and frequency set using keypad and displayed using LCD. Actually, power supply is designed and manufactured. Through the experiments, the performance of output voltage and frequency control is verified.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.2
• /
• pp.3-9
• /
• 2016

In this paper, we propose a Radio over Fiber system for small cell applications and for mobile fronthaul networks supporting cloud-radio access networks(RAN). We built a system with a downlink employing orthogonal frequency division multiplexing (OFDM) techniques and an uplink using single carrier-frequency multiple access(SC-FDMA). System parameters are evaluated for various subcarrier modulations and the results of link performance measurements are analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.7
• /
• pp.1242-1246
• /
• 2007

In this study, FSS(Frequency Selective Surface) with Koch Fractal Curve slot is positioned on the conventional single layer microstrip patch antenna. Numerical results of the proposed antenna bandwidth and the antenna gain are increased compared with those of the conventional single layer microstrip patch antenna. In the future, the fractal geometry of the slot in FSS(Frequency Selective Surface) as a supplementary microstrip patch is researched for the enhancement of the microstrip patch antenna characteristics.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.6
• /
• pp.490-495
• /
• 2020

The power loss of large-capacity systems using single-phase inverters has attracted considerable attention. In this study, optimal switching sequence model prediction control at a low switching frequency is proposed to reduce the power loss in a high-power inverter system, and a compensation method that can be utilized for model prediction control is developed to reduce errors in accordance with sampling values. When a three-level, single-phase inverter using a switching frequency of 600 Hz and a sampling frequency of 12 kHz is adopted, the power factor is improved from 0.95 to 0.99 through 3 kW active power control. The performance of the controller is also verified.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.39-45
• /
• 2006

This paper describes an effective and fast algorithm for GPS carrier-phase ambiguity resolution (AR) which can apply for structure monitoring, and a series of simulation analyses have been carried out to demonstrate the performance of the algorithm. The results show that single-frequency AR performance is significantly improved In term of Time-To-Fix-First (TTFF) ambiguity.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.1
• /
• pp.1-7
• /
• 1998

In this paper, an incoherent imaging of a conducting cylinder illuminated by the single-frequency time-harmonic plane wave is obtained via the back-projections of the intensity patterns of the forward total electric field scattered from this object in the circular rotational measurement configuration. The pheonmenon that interference fringes generated in the itesity patterns is removed in the back-projection process is interpreted numerically. This imaging method is validated by imagining conducting circular cylinders and the conditions to ge beter image are investigated.