• Journal of Navigation and Port Research
• /
• v.29 no.10 s.106
• /
• pp.877-882
• /
• 2005

It is necessary that Fail-Safe Seaway technology providing a continuous navigation solution though fault of navigation system is occurred in sea. This paper focus on signal processing of GPS receiver, one of receivers using the software radio technology to implement a integrated radio navigation system including satellite-based and ground-based navigation systems. It is difficult to implement the software GPS receivers using a commercial processor because of the heavy computational burden for processing the GPS signals in real time. This paper proposes an efficient multi-bit GPS signal processing scheme to reduce the computational burden for processing the GPS signals in the software GPS receiver. The proposed scheme uses a compression concept of the multi-bit replica signals and patterned look-up table method to generate the correlation value between the GPS signals and the replica signals.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.37-42
• /
• 2005

It is necessary that Fail-Safe Seaway technology providing a continuous navigation solution though fault of navigation system is occurred in sea. This paper focus on signal processing of GPS receiver, one of receivers using the software radio technology to implement a integrated radio navigation system including satellite-based and ground-based navigation systems. It is difficult to implement the software GPS receivers using a commercial processor bemuse of the heavy computational burden for processing the GPS signals in real time. This paper proposes an efficient multi-bit GPS signal processing scheme to reduce the computational burden for processing the GPS signals in the software GPS receiver. The proposed scheme uses a compression concept of the multi-bit replica signals and patterned look-up table method to generate the correlation value between the GPS signals and the replica signals.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2744-2746
• /
• 2005

텔레매틱스(telematics)는 무선 네트워크를 통해 운전자에게 운전은 물론 생활에 필요한 다양한 정보를 실시간으로 제공하는 서비스이다. 이러한 텔레매틱스 시스템은 운영시스템에 따라 내부시스템, 무선통신 네트워크, 텔레매틱스 센터부분으로 크게 나눠볼 수 있다. 이중에서 내부시스템 및 무선통신 네트워크에 Bluetooh로 다양한 응용이 가능하다. Bluetooth는 다양한 주변기기들의 사용으로 인한 차내 배선의 복잡성을 해소하고 주변 기기들에 대한 중앙 집중 인터페이스를 가능하게 할 수 있다. 또한 Bluetooth는 GPS 항법 시스템 개발자가 최상의 GPS 시스템을 구현하는 데 있어 가장 비용 효과적이고 상용화 시간을 최소화하며 상호 운용성이 가장 뛰어난 솔루션을 제공한다. 이에 본 논문에서는 텔레매틱스 시스템에서 내부시스템 및 무선통신 네트워크에 적용될 수 있는 Bluetooth 네트워크를 구성하고 차량의 진동에 의한 전파 오류, 전파 반사, 전파간의 간섭에도 안정적으로 동작하기 위한 방법을 제시한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.10a
• /
• pp.266-267
• /
• 2015

해상 활동에 있어서 해상교통의 핵심정보인 항법신호의 안전을 강화하기 위하여, 본 논문에서는 국내에서 발생한 전파간섭 발생 사례와 영향, 그리고 DGNSS 기준국 무결성 기능의 한계에 대해 조사하고 그 대응방안을 운영자 및 선박 운항자 관점에서 분석한다. 그 대안의 하나로서 항만 항법신호(PNT)의 무결성 감시 기술과 그 신뢰도를 결정하여 사용자에게 제공하기 위한 항만 PNT 무결성 감시 서비스에 대해 소개한다. 그리고 특정 항만에 항법신호 감시 시스템을 구축하여, 개발 시스템의 시범 운영 테스트를 통해 그 실용화 가능성을 제시한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2007.12a
• /
• pp.98-99
• /
• 2007

It is necessary to use satellite radio navigation system as well as satellite radio navigation augmentation system such as differential Global Positioning System to achieve the positioning accuracy and reliability requested by International Maritime Organization in port and coastal area. Especially, position accuracy of DGPS user is effected by accuracy of pseudorange correction broadcasted from DGPS reference station. This paper shows pseudorange correction calculation algorithm adopting a non-common error estimation filter in order to improve accuracy of pseudorange correction. Finally, this paper verifies that the pseudorange correction calculated by adopting a non-common error estimation filter satisfies performance specifications of RTCM.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.2
• /
• pp.97-102
• /
• 2019

The GNSS(Global Navigation Satellite System) provides important information such as Position and Navigation, Timing(PNT) to various weapon systems in the military. as a result, applications that employ satellite navigation systems are increasing. therefore, a number of studies have been conducted to deceive the weapon systems that employ GNSS. GNSS spoofing denotes the transmission of counterfeit GNSS-like signals with the intention to produce a false position and time within the victim receiver. In order to deceive the victim receiver, spoofing signal should be synchronized with GNSS signal in doppler frequency and code phase, etc. In this paper, Civilian GPS L1 C/A spoofing signals have been evaluated and analyzed by SDR receiver.

• Electronics and Telecommunications Trends
• /
• v.36 no.4
• /
• pp.61-71
• /
• 2021

Navigation satellite systems (GPS, GLONASS etc.) provide three main services, i.e., positioning for location based services, navigation for multi-modal transportation services, and timing for communication and critical infrastructure services. They were started as military systems but were extended to civil service. Navigation satellite navigation system began with GPS in the USA and GLONASS in Russia at nearly the same time. Indian NavIC and Chines BDS announced their FOCs in 2016 and 2020, respectively and European Galileo and Japanese QZSS are catching up others. In these days, Navigation Satellite System, Positioning, Navigation, and Timing services are part of our daily life very closely. They are required for autonomous driving car, Unmanned vehicles like UAV, UGV, and UMV, 5G/6G telecommunications, world financial system, power system, survey, agriculture, and so on. The services among navigation satellite systems are very competitive and also cooperative one another. This article describes the status of these systems and evolution in the technical and service senses, which may be helpful for planning korea positioning system(KPS).

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.7
• /
• pp.666-673
• /
• 2008

To construct the accurate radio satellite navigation system, the efficient communication each satellite with the ground station is very important. Throughout the communication, the orbit of each satellite can be corrected, and those information will be used to analyze the satellite satus by the operator. Since there are limited resources of ground station, the schedule of antenna's azimuth and elevation angle should be optimized. On the other hand, the satellite in the medium earth orbit does not pass the same point of the earth surface due to the rotation of the earth. Therefore, the antenna pass schedule must be updated at the proper moment. In this study, Q learning approach which is a form of model-free reinforcement learning and genetic algorithm are considered to find the optimal antenna schedule. To verify the optimality of the solution, numerical simulations are conducted.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.2
• /
• pp.272-279
• /
• 2016

Many researches on use of local ground navigation systems can be found to overcome vulnerability of GNSS. Effective use of an altimeter is proposed in GNSS/DME integrated navigation systems. A weighted DOP based on statistics of measurement error is derived for a given vehicle motion trajectory. From the derived DOP, the vertical error is estimated. By comparing the estimated vertical error with error specification of the altimeter, use of the altimeter is determined in the GPS/DME integrated navigation systems. In order to show effectiveness of the proposed method, 50 times Monte-Carlo simulations were performed for a GPS/DME integrated navigation system. The results show that the proposed method gives more accurate navigation outputs when the number of GPS satellites in view varies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.04a
• /
• pp.370-371
• /
• 2010

The Long Range Navigation (LORAN) had been mainly used world-wide until GPS (Global Positioning System) activation. In particular. it was essential junctionality for the ships to sail the oceans. However, according to the industry's developing, the current accuracy of Loran is insufficient for the utilization such as the harbour approach, the land navigation and the field of precise timing. Therefore it is necessary the study on the improvement of the positioning accuracy of Loran. The method of its improvement is to measure and compensate the propagation time delay, that is, additional secondary factor (ASF) between the transmitter and user's receiver. This study shows the technique for the absolute time delay measurement without a time of coincidence (TOC) table, and represents the ASF measurement result between Pohang transmitter station(9930M) and each measure points.