• Journal of Electrical Engineering and Technology
• /
• v.6 no.5
• /
• pp.723-730
• /
• 2011

The GPS modernization program offered a new civil signal on the L2 band, and the first modernized GPS Block IIR satellite was launched in September 2005. Currently, eight GPS Block IIRM satellites and two Block IIF satellites transmit L2C signal. The L2C signal contains two codes of CM and CL that are much longer than the L1 C/A code. Thus, the acquisition of the CM and CL codes takes more time compared with that of L1 C/A code. Under the assumption that the L2C signal is strong enough for detection, this paper suggests rapid acquisition methods for the GPS L2C signals for software receivers and compares its performance with that of other methods.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.11a
• /
• pp.59-65
• /
• 2003

In order to reduce the cost of software maintenance including software modification, we suggest the object oriented program with checking the version of application program using the Java language and the technique of executing the downloaded application program via network using the application manager. In order to change the traditional scheduler to the application manager we have adopted the Xlet concept in the nuclear fields using the network. In usual Xlet means a Java application that runs on the digital television receiver. The Java TV Application Program Interface(API) defines an application model called the Xlet application lifecycle. Java applications that use this lifecycle model are called Xlets. The Xlet application lifecycle is compatible with the existing application environment and virtual machine technology. The Xlet application lifecycle model defines the dialog(protocol) between an Xlet and its environment

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.2
• /
• pp.127-134
• /
• 2022

In this paper, a low-cost, flexible GPS simulator based on USRP is designed as a general-purpose software wireless front-end. The simulator consists of a software GPS signal generator and a USRP-based RF transmitter. The simulator supports various scenarios including specified reception time, quantization bit level, I/Q data types, IF frequency, sampling frequency, SNR, ionospheric delay and user dynamics. The generated GPS RF signal is verified using the spectrum analyzer and off-the-shelf GNSS receivers such as U-blox M8T. The experimental results shows that the difference between generated and real live signal is ignorable. It is expected that designed GPS simulator can be used to GNSS signal design, receiver design and signal processing algorithms such as anti-jamming.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.2
• /
• pp.113-118
• /
• 2013

In this paper, spoofing effects on a GNSS receiver were analyzed. The spoofer (spoofing device) was classified to two categories. One is an active spoofer and the other is a passive spoofer. The active spoofer was considered for analysis. For the analysis of spoofing effects on a GNSS receiver, a real-time GNSS spoofing simulator was developed. The simulator was consisted with two parts which are a baseband signal generation part and a RF up-conversion part. The first GNSS baseband signal was generated according to spoofing parameters such as range, range rate, GNSS navigation data, spoofing to GNSS signal ratio, and etc. The generated baseband signal was up-converted to GNSS L1 band. Then the signal transmitted to a GNSS signal. For a perfect spoofing, a spoofer knew an accurate position and velocity of a spoofing target. But, in real world, that is not nearly possible. Although uncertainty of position and velocity of the target was existed, the spoofer was operated as an efficient jammer.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.875-880
• /
• 2018

This paper proposes a novel combined compensation structure in the infrared receiver chip. For the infrared communication chip, the current-voltage (I-V) convert circuit is crucial and important. The circuit is composed by the transimpedance amplifier (TIA) and the combined compensation structures. The TIA converts the incited photons into photocurrent. In order to amplify the photocurrent and avoid the saturation, the TIA uses the combined compensation circuit. This novel compensation structure has the low frequency compensation and high frequency compensation circuit. The low frequency compensation circuit rejects the low frequency photocurrent in the ambient light preventing the saturation. The high frequency compensation circuit raises the high frequency input impedance preserving the sensitivity to the signal of interest. This circuit was implemented in a $0.6{\mu}m$ BiCMOS process. Simulation of the proposed circuit is carried out in the Cadence software, with the 3V power supply, it achieves a low frequency photocurrent rejection and the gain keeps 109dB ranging from 10nA to $300{\mu}A$. The test result fits the simulation and all the results exploit the validity of the circuit.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.251-254
• /
• 2018

Research about IoT system that utilizes variation of wireless received signal according to the changing of the surrounding environment are actively being studied. In this paper, firstly we proved that the received signal strength changes according to the ambient temperature variation. Then, we proposed the fire detection scheme by using received signal strength variation when the signal exchange between fixed transmitter and receiver periodically. The proposed scheme consists of the received signal strength change detection unit and the internal receiver temperature detection unit which prevents misunderstanding the received signal strength variation by the changing of wireless channel environment as outbreak of fire. The proposed scheme has the advantage of being able to support the existing receiver through software upgrade without additional device.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.1984-1986
• /
• 2001

In order to provided continuous solutions, latest developing navigation systems tend to integrate GPS receiver with INS or DR. Using the GPS carrier-phase measurements, an attitude GPS receiver with three antennas obtain the 3-dimensional attitude such as roll, pitch, and heading as well as position and velocity. With these angle measurements, in the attitude GPS/INS integrated system, attitude or gyro errors can be directly compensated. In this paper, we develop an integrated navigation system that combines attitude GPS receiver with INS. The performance of real-time integrated navigation system is determined by not only the implements of integration filter but also the synchronization of measurements. To meet these real-time requirements, the navigation software is implemented in multi-tasking structure in this paper. We also employ time-synchronization technique in the multi-sensor fusion. Experimental results show that the performance of the attitude GPS/INS integrated system is consistent even when cycle-slip occurs in carrier-phase measurements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.285-285
• /
• 2009

Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.8
• /
• pp.770-784
• /
• 1991

In this paper, we have studied the transmission reception method and data structure of the radio data system which was recommendedby EBU. We have develped the novel software that has processing capability of 5 primary features of RDS services, and experimanted the auto-tuning mechanism and LCD display. The developed RDS receiver system has the complete compatibility with the conventional FM car streo system, and we have confirmed the realization validity via the hardware experimentation.

• Proceedings of the KIEE Conference
• /
• 2002.11c
• /
• pp.613-616
• /
• 2002

This paper has been studied an improvement of receive sensitivity for RF module of Industrial Scientific Medical(ISM) Band. In the paper, Also this paper handles receive sensitivity progress of RF module in ISM band. how to improve receive sensitivity adds to Surface Acoustic Wave(SAW) filter, Low Noise Filter(LNA), etc and insulates receiver and transmitter. And then the circuit is inspected by the effective range test of receiver and transmitter. And this Paper was designed that micro-controler controls the part of RF by software.