• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.158-165
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• 1990

We have developed a L1 band (1575.42 MHz), C/A (Coarse/Acquisition) code GPS (Global Positioning System) receiver for precise time comparison and evaluated the performance of the receiver. The GPS measurements have been carried out between cesium clocks onboard the GPS satellites and the master clock of Korea Standards Research Institute (KSRI) using the GPS receiver. An accuracy of time transfer better than 100ns was obtained.

• Journal of Navigation and Port Research
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• v.34 no.2
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• pp.97-103
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• 2010

It has been recognized that the risk from the vulnerability of GPS can lead to the extreme damage in the infrastructure of the civil and military in recent years. As an example, the intentional interference to GPS signal, named GPS jamming, was really performed to misguide GPS guided weapons during Iraq war in 2003, and the fact has also followed by the serious issues on GPS in civilian community. In the modernized military society, the navigation warfare(NAVWAR) based on the GPS jamming has been emerged and introduced as a military operation. The intentional interference to the future global navigation satellite system(GNSS) involving GPS must be also an important issue to civilian users in near future. This study is focused on the fundamental research prior to the research on "Potential principle of NAVWAR" under NAVWAR of the future warfare. In this paper, we would study on the investigation of NAVWAR based on electronic warfare(EW) and analyze characteristics of the jamming against GNSS's receivers. Then the general mechanism on GNSS jamming is proposed.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.455-461
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• 2004

Now, GPS survey is used on equipment from leisure to precise geodetic survey and nation admits the result of GPS survey. When surveyors perform precise GPS survey, they use post processing method but they greatly use real time processing method to consider field status. Especially, when surveyors measure the result of moving target, they use real time GPS survey to the best method. For this study, the author precisely surveyed distance of ship launching from shipyard on real time using real time precise GPS method. In this paper, the author compares and examines the accuracy of first real time precise GPS survey method nationally and the capability on use. And the author performed real time precise GPS survey in NOKBONG and 21C shipyard positioning at GEOJEDO.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.499-505
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• 2004

현재 국내에서 활발히 이루어지고 있는 GPS 정밀측지측량은 획득된 GPS 관측값의 결과값이 GPS 기준점의 기하학적 강도와 분산계수의 상관관계의 연관성과의 분석없이 사용되고 있는 문제점을 파악하고 육지와 해상의 통합지리정보시스템구축을 위한 수치지도와 전자해도의 통합투영의 필요성에 의해서 이루어졌다. 본 연구의 목적은 크게 GPS 관측값의 정밀도를 향상시키는 방법과 수치지도와 전자해도의 통합투영으로 GPS 기준점들을 이용한 수치지도와 전자해도상의 경계선 오차량을 비교검토를 통해 수치지도와 전자해도의 통합관리의 방향을 제시하는데 있다. GPS 관측값의 정밀도 향상을 위한 방법제시를 위하여 GPS 망조정에 사용되는 3점의 기준점에 대한 기하학적인 강도에 따른 정밀도 분석방법과 분산계수의 변화에 따른 GPS 관측값들의 정밀도 분석방법으로 나누어 검토하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.789-797
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• 2006

A new method for the GPS repeater based indoor positioning is proposed and its feasibility is verified by experiments in previous paper. But the problems how can identify switching GPS repeater's ID and when switching will be occurred are remained. To solve the problem faced with, we propose the time synchronized switching GPS repeater and the methods of the detection of switching time and the estimation of TDOA. First, switching GPS repeater retransmits the signals synchronized on GPS time, sequentially. Always, first switching time is synchronized with 1 PPS. Second, we formulate the detection of switching time and the estimation of TDOA and propose the various methods. No method is existed absolutely superior to others in any conditions but the method is existed superior to others in specific condition. Finally, feasibility of indoor positioning using time-synchronized switching GPS repeater is evaluated through experiments in anechoic chamber and general environment with multipath.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.13-21
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• 2004

GPS is widely used in various applications since GPS receivers are capable of measuring precise position and velocity in any weather condition for a relatively low cost. However, GPS requires more than four simultaneously visible GPS satellites for optimal performance. In high-motion, high-attitude-changing applications, there exist some situations where less than four satellites are visible or where the dilution of precision (DOP) is high. In this paper, we propose a simulation algorithm that predicts the performance of GPS navigation according to changes in vehicle attitude. We have compared simulation results with experimental results, where simulation results of the proposed algorithm are shown to closely match actual experimental data. This algorithm could be used to predict GPS navigational performance and to determine optimal GPS antenna position.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.169.2-169.2
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• 2012

고기동 위성에 탑재된 GPS 수신기의 위성체의 기준 위치, 속도 및 시간의 정보를 제공한다. 특히 저궤도 관측위성은 빠른 동적 특성으로 인하여 GPS 위성 신호 획득 및 추적이 어려울 경우 연속적인 항행해를 제공하기 어려울 수 있다. 이를 위하여 위성 GPS 수신기는 지상용과 달리 넓은 대역폭의 신호 획득 및 추적이 가능한 RF수신단이 탑재되어 있으며 필터 기반의 궤도전파기가 탑재되어 있어 있다. 뿐만 아니라 GPS 수신기기의 상태 데이터 제공 및 고속 데이터 처리를 위하여 고성능 CPU가 탑재되어 있다. 특히 탑재된 궤도전파기는 고성능 필터 기반으로 설계되어 있으며 이를 이용하면 GPS 신호 추적이 되지 않은 상황에서도 비교적 정확하고 연속적인 항행해가 제공하게 된다. 본 논문에서는 저궤도 관측위성에 탑재된 GPS 수신기가 초기 위성운영에서 어떠한 절차에 의하여 동작이 되며 위성의 빠른 동적 특성에서 GPS 수신기의 가시성 및 추적 위성개수 분석 및 이를 바탕으로 위치 및 속도 정밀도가 어느 정도 되는지에 대한 성능 분석 결과를 정리 하였다. 본 논문 결과는 향후 고기동 위성의 GPS 수신기 및 관련 운영에 도움이 될 것으로 판단된다.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.4 no.1
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• pp.1-6
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• 2005

As an application of the GPS/SDINS integration for its synergistic results, the alignments of the SDINS utilizing GPS carrier phase rate measurements is introduced. A measurement model of GPS carrier phase rate, which does not require integer ambiguity determination process, is newly derived in order to be adopted with the SDINS in-flight alignment process. For in-flight alignment, the performance of the GPS/SDINS integration method suggested in this paper is analyzed using the covariance analysis.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.59-70
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• 2022

In this paper, a GPS/GF-INS integrated navigation system is proposed, in which the high rate attitude aiding signal, the high rate position and velocity aiding of GPS receiver is used for the cube structure of the GF-IMU, effectiveness of the proposed GPS/GF-INS integrated navigation system was shown when the vehicle follows two trajectories, circling and spiraling. Performance evaluation results show that the proposed GPS/GF-INS integrated navigation method gives better navigation outputs when the attitude output of GPS is used and more better navigation outputs are obtained when the rate of GPS aiding signal is higher.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1121-1122
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• 2023

현대사회에서 중요하게 사용되는 GPS 정보를 활용하는데 있어, 고성능 GPS 수신기를 사용하는데 있어 비용적인 문제가 발생한다. 경제성을 개선하여 더 다양한 분야에서 GPS 정보를 활용하기 위해 딥러닝을 통해 정밀한 GPS 정보를 얻고자 한다. 본 논문에서는 다수의 저성능 GPS 를 학습시켜 딥러닝 모델을 구현하고 성능을 평가한다. 제안한 모델을 사용할 경우, 저성능 GPS 만으로도 고성능 GPS 와 오차미터가 1m 까지 줄어드는 효과를 얻을 수 있다.