• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.223-228
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• 2006

The main purpose of this paper is to describe the code tracking performance of a non-coherent digital delay lock loop (DLL) or coherent DLL while tracking GNSS signal in the presence of signal masking. The masking effect is usually caused by buildings that obscure the signal in either a periodic or random manner. In some cases, ideal masking is used to remove random or periodic interference. Three types of the masked signal are considered - no masking, periodic masking, and random masking of the signal input to the receiver. The mean time to lose lock (MTLL) of the code tracking loop are evaluated, and some numerical result and simulation results are reported. Finally, the steadystate tracking errors on the performance of the tracking loop in interference environment are also presented.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.53-58
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• 2019

Since floating facility with mooring system can be moved and rotated by wind or other environmental variables, the error in azimuthal angle must be compensated using a GPS receiver and geo-magnetic sensor. Accordingly, when an existing photovoltaic tracking algorithm is applied to a floating photovoltaic system, it is difficult to do the optimal solar tracking. In this paper, an effective azimuthal angle algorithm is develop for the photovoltaic tracking in floating condition. In order to verify the developed algorithm, the prototype of the floating photovoltaic system is manufactured and the developed algorithm is applied to the system. The algorithm shows a good tracking feasibility on the prototype.

• Advances in aircraft and spacecraft science
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• v.2 no.1
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• pp.95-108
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• 2015

Automatic Dependent Surveillance Broadcast (ADS-B) is quickly being adopted by aviation safety authorities around the world as the standard for aircraft tracking. The technology provides the opportunity for live tracking of aircraft positions within range of an ADS-B receiver stations. Currently these receiver stations are bound by land and local infrastructural constraints. As such there is little to no coverage over oceans and poles, over which many commercial flights routinely travel. A low cost space based ADS-B receiving system is proposed as a constellation of small satellites. The possibility for a link between aircraft and satellite is dependent primarily on proximity. Calculating the likelihood of a link between two moving targets when considering with the non-periodic and non-uniform nature of actual aircraft flight-paths is non-trivial. This analysis of the link likelihood and the performance of the tracking ability of the satellite constellation has been carried out by a direct simulation of satellites and aircraft. Parameters defining the constellation (satellite numbers, orbit size and shape, orbit configuration) were varied between reasonable limits. The recent MH370 disappearance was simulated and potential tracking and coverage was analysed using an example constellation. The trend of more satellites at a higher altitude inclined at 60 degrees was found to be the optimal solution.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.71-76
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• 2014

In this paper, we proposed the 1-channel monopulse receiver which has the new configuration and described the operation procedures. Also, we compared and analyzed the proposal receiver and the general 3-channel monopulse receiver. As a result, it is apparent that the monopulse ratio of the proposal receiver is equal to that of the 3-channel monopulse receiver. The proposal receiver achieve the simple receiver configuration and the simple tracking procedures, as contrasted with the 3-channel monopulse receiver. Also, the proposal receiver has advantages in terms of size, weight, cost and power. Because the proposal monopulse receiver require 1-channel receiver and need not the signal processor in comparison with 3-channel monopulse receiver which require 3-channel receiver and need the signal processor.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.3-9
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• 2015

In this paper, we propose the operation procedures of the 1-channel monopulse receiver which achieves the new configuration. Also, we analyzed the monopulse ratio and the target angle accuracy of the fabricated receiver by using the monopulse signal generator developed for verifying the proposal equipment. As a result, it is apparent that the monopulse ratio of the proposal receiver is equal to that of the 3-channel monopulse receiver. Also, the fabricated receiver exhibits the target angle accuracy with fewer than 0.1 RMS. The proposal receiver achieves the simple receiver configuration and the simple tracking procedures, as contrasted with the 3-channel monopulse receiver. Also, the proposal receiver has advantages in terms of size, weight, cost and power. Because the proposal monopulse receiver requires 1-channel receiver and needs not the signal processor in comparison with 3-channel monopulse receiver which requires 3-channel receiver and need the signal processor.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.235-240
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• 2006

Ionospheric scintillation induces a rapid change in the amplitude and phase of radio wave signals. This is due to irregularities of electron density in the F-region of the ionosphere. It reduces the accuracy of both pseudorange and carrier phase measurements in GPS/satellite based Augmentation system (SBAS) receivers, and can cause loss of lock on the satellite signal. Scintillation is not as strong at mid-latitude regions such that positioning is not affected as much. Severe effects of scintillation occur mainly in a band approximately 20 degrees on either side of the magnetic equator and sometimes in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. This paper focuses on estimation of the effects of ionospheric scintillation on GPS and SBAS signals using a software receiver. Software receivers have the advantage of flexibility over conventional receivers in examining performance. PC based receivers are especially effective in studying errors such as multipath and ionospheric scintillation. This is because it is possible to analyze IF signal data stored in host PC by the various processing algorithms. A L1 C/A software GPS receiver was developed consisting of a RF front-end module and a signal processing program on the PC. The RF front-end module consists of a down converter and a general purpose device for acquiring data. The signal processing program written in MATLAB implements signal acquisition, tracking, and pseudorange measurements. The receiver achieves standalone positioning with accuracy between 5 and 10 meters in 2drms. Typical phase locked loop (PLL) designs of GPS/SBAS receivers enable them to handle moderate amounts of scintillation. So the effects of ionospheric scintillation was estimated on the performance of GPS L1 C/A and SBAS receivers in terms of degradation of PLL accuracy considering the effect of various noise sources such as thermal noise jitter, ionospheric phase jitter and dynamic stress error.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.16-24
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• 1997

In order to prevent the presence of the residual phase difference at the discriminator output by the existing AFC techniques, we propose a new automatic frequency control(AFC) tracking algorithm for QPSK demodulation at the digital direct broadcasting satellite(DBS) receiver, which we call a rotational decision-directed AFC(RDDAFC). The RDDAFC rotates the decision boundary for the kth received symbol by the frequency deterctor output of the (k-1)th received symbol. Tracking performances of carrier frequency offset by the proposed RDDAFC algorithm are evaluated through computer simulations under the practical DBS channel conditions with a carrier frequency offset of 2.3MHz when S/N equals 2dB. Test results show that the total pull-in time of the RDDAFC is 1.697msec for 10$^{-3}$ SER before forwared error correction at the receiver.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.49-58
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• 2003

Compared with generic GPS receiver, post-processing software GPS receiver has many advantages for high dynamic vehicle tracking. It has the advantage of the application of various tracking algorithms and aiding schemes. The post-processing system observes the carrier phase measurement data from the recorded GPS signals, detects and isolates the cycle slip. The observed carrier phase data and the raw data of the reference station are processed by carrier phase DGPS scheme. And the integer ambiguity resolution algorithm is used for resolving single frequency carrier phase ambiguity. The results of static and real flight test are presented and show that the proposed GPS translator processing system satisfies submeter accuracy.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.133-139
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• 2010

GNSS receiver which uses the weak satellite signal is very vulnerable to the intentional jamming or non-intentional electromagnetic interference. It is a very simple method among the use method of GNSS receiver to vary tracking loop bandwidth of satellite signal appropriately as the jamming signal level. In this paper, this anti-jamming performance is experimented and analyzed in the laboratory and the anechoic chamber by the GNSS simulator to generate the satellite signal and the jamming signal generator to generate the jamming signal.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.275-275
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• 2000

This paper designs a digital correlator for the integrated GPS/GLONASS receiver consisting of DCO, carrier cycle counter, code generator, code phase counter, mixer, epoch counter, accumulator. It is designed using Verilog-HDL(Verilog-Hardware Description Language) and synthesized using EDA(Electronic Design Automation) tools. The performance of the designed digital correlator is verified by the functional simulation and real satellite tracking experiments.