• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.75-83
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• 2024

In order to reduce the time and cost of developing a navigation system, a performance evaluation platform can be used. A User Interface (UI) is required to effectively evaluate the performance, which sets parameters and gives navigation sensor signals and data display, and also displays navigation results. In this paper, a LabVIEW-based UI design method for multi-integrated navigation systems is proposed and implementation results are presented. The UI consists of a signal and data generation part and a signal and data processing part. The signal and data generation part sets parameters for the signal and data generation and displays the navigation sensor signal and data generation results. The signal and data processing part sets parameters for the signal and data processing and displays the navigation results. The signal and data generation part and signal and data processing part are designed to satisfy the requirements of the UI for a performance evaluation of the navigation system. In order to show the usefulness of the proposed UI design method, parameters of the signal and data generation and the signal and data processing are set through the LabVIEW-based UI, and the Global Positioning System (GPS) signal and inertial measurement unit data generation results and the navigation results of a GPS Software Defined Receiver (SDR) and inertial navigation system are confirmed. The implementation results show that the proposed UI design method helps users conduct an effective performance evaluation of navigation systems.

• Journal of Positioning, Navigation, and Timing
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• 제3권3호
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• pp.99-105
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• 2014

A graphic processing unit (GPU) can perform the same calculation on multiple data (SIMD: single instruction multiple data) using hundreds of to thousands of special purpose processors for graphic processing. Thus, high efficiency is expected when GPU is used for the generation and correlation of satellite navigation signals, which perform generation and processing by applying the same calculation procedure to tens of millions of discrete signal samples per second. In this study, the structure of a GPU-based GNSS simulator for the generation and processing of satellite navigation signals was designed, developed, and verified. To verify the developed satellite navigation signal generator, generated signals were applied to the OEM-V3 receiver of Novatel Inc., and the measured values were examined. To verify the satellite navigation signal processor, the performance was examined by collecting and processing actual GNSS intermediate frequency signals. The results of the verification indicated that satellite navigation signals could be generated and processed in real time using two GPUs.

• Journal of Positioning, Navigation, and Timing
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• 제13권2호
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• pp.149-158
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• 2024

Global Navigation Satellite System (GNSS) receivers are becoming increasingly sophisticated, equipped with advanced features and precise specifications, thus demanding efficient and high-performance hardware platforms. This paper presents the design and implementation of a Field-Programmable Gate Array (FPGA)-based GNSS receiver development platform for multi-band signal processing. This platform utilizes a FPGA to provide a flexible and re-configurable hardware environment, enabling real-time signal processing, position determination, and handling of large-scale data. Integrated signal processing of L/S bands enhances the performance and functionality of GNSS receivers. Key components such as the RF frontend, signal processing modules, and power management are designed to ensure optimal signal reception and processing, supporting multiple GNSS. The developed hardware platform enables real-time signal processing and position determination, supporting multiple GNSS systems, thereby contributing to the advancement of GNSS development and research.

• Journal of Positioning, Navigation, and Timing
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• 제7권1호
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• pp.1-14
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• 2018

The Global Positioning System (GPS) provides more accurate positioning estimation performance by processing L1 and L2 signals simultaneously through dual frequency signal processing technology at the L-band rather than using only L1 signal. However, if anti-spoofing (AS) mode is run at the GPS, the precision (P) code in L2 signal is encrypted to Y code (or P(Y) code). Thus, dual frequency signal processing can be done only when the effect of P(Y) code is eliminated through the L2 signal processing technology. To do this, a codeless technique or semi-codeless technique that can acquire phase measurement information of L2 signal without information about W code should be employed. In this regard, this paper implements L2 signal processing technology where two typical codeless techniques and four typical semi-codeless techniques of previous studies are applied and compares their performances to discuss the optimal technique selection according to implementation environments and constraints.

• 한국항행학회논문지
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• 제13권3호
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• pp.319-326
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• 2009

본 논문에서는 위성항법신호감시국용 GPS/갈릴레오 복합 수신기에서의 소프트웨어 기반의 GPS L1 및 갈릴레오 E1/E5a 신호처리 결과를 기술한다. 성능 검증을 위해 GNSS RF 신호 시뮬레이터 또는 GPS 위성의 실제 신호를 사용하였고, 세부적으로는 광대역 안테나, 112MHz 샘플링 주파수 및 8비트 양자화 레벨을 제공하는 RF/IF 유니트를 이용하여 갈릴레오 시험위성인 지오베-A(GIOVE-A) E1 신호처리를 통해, 갈릴레오 신호처리를 검증하고, FPGA 기반의 신호처리 보드상에서의 시험결과를 제시한다.

• 한국항공우주학회지
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• 제36권10호
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• pp.1003-1010
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• 2008

본 논문은 RLG의 신호처리 기법인 Trapping 기법 적용시 각속도와 가속도의 측정시점 불일치에 의해 발생되는 오차를 보상하는 기법에 관한 연구이다. RLG의 대표적인 신호처리 기법인 Stripping 신호처리 기법과 Trapping 신호처리 기법에 대하여 각 기법의 오차요인을 분석하고 이에 대한 모델링을 수행하였다. 그리고 Trapping 기법 적용시 각속도와 가속도 측정시점 불일치에 의해 발생되는 오차에 대한 모델링을 통하여 항법오차에 미치는 영향을 분석하였으며 이를 감소시키기 위한 새로운 신호처리 기법을 제안하고 시뮬레이션 및 시험을 통하여 이에 대한 성능분석 결과를 제시하였다. 성능 분석결과 본 논문에서 제시한 신호처리 기법이 기존의 방법에 비하여 항법오차를 크게 감소시키는 것을 확인할 수 있었다.

• 한국항해학회지
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• 제24권5호
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• pp.435-441
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• 2000

This paper deals with the development of RACOM(Radar Signal Detecting ＆ Processing Computer). RACOM is a radar display system specially designed for radar scan conversion, signal processing and PCI radar image display. RACOM contains two components； i )RSP(Radar Signal Processor) board which is a PCI based board for receiving video, trigger, heading & bearing signals from radar scanner ＆ tranceiver units and processing these signals to generate high resolution radar image, and ⅱ）Applications which perform ordinary radar display functions such as EBL, VRM and so on. Since RACOM is designed to meet a wide variety of specifications(type of output signal from tranceiver unit), to record radar images and to distribute those images in real time to everywhere in a networked environment, it can be applicable to AIS(Automatic Identification System) and VDR(Voyage Data Recorder).

• Journal of Positioning, Navigation, and Timing
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• 제6권3호
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• pp.87-94
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• 2017

GNSS modernization and development is in progress throughout the globe, and it is focused on the addition of a new navigation signal. Accordingly, for the next-generation GNSS signals that have been developed or are under development, various combinations that are different from the existing GNSS signal structures can be introduced. In this regard, to design an advanced signal, it is essential to clearly understand the effects of the signal structure and design variables. In the present study, the effects of the GNSS spreading code period and GNSS data bit duration (i.e., signal design variables) on the signal processing performance were analyzed when the data bit transition was considered, based on selected GNSS signal design scenarios. In addition, a method of utilizing the obtained result for the design of a new GNSS signal was investigated.

• 한국항해학회지
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• 제19권2호
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• pp.115-120
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• 1995

Recently, the ship automation technology(SAT) has received great attention for the efficient management of the ship with minimum human efforts. Among the SAT, a distance measuring system, the key element is the signal processing unit for the interpretion of the received signal from the remote sensing of the oil tank. In this paper, the tank monitoring system using FM-CW is described for the oil tank level guage measurement with an emphsis of signal processing unit.

• 한국위성정보통신학회논문지
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• 제2권2호
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• pp.64-68
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• 2007

본 논문에서는 기존의 GPS 항법 신호와 유럽에서 새롭게 추진되고 있는 갈릴레오 위성 항법 신호를 동시에 수신할 수 있는 광대역 고정밀 위성 항법 수신기의 RF 수신단 장치 설계 및 제작 결과에 대하여 기술하고 있다. 고정밀 광대역 위성 항법 수신기는 L - 대역 안테나, 항법 신호별 RF/IF 변환부, 그리고 고성능 기저대역 신호 처리부로 구성되어진다. L - 대역 안테나는 $1.1GHz{\sim}1.6\;GHz$를 수신할 수 있어야 하며, 항법 위성이 지평선 가까이에 있을 경우의 항법 신호를 수신할 수 있어야 한다. 갈릴레오 위성 항법 신호는 L1, E5, E6의 서로 다른 대역의 신호를 가지고 있으며, 신호 대역폭이 20MHz 이상으로 기존의 GPS위성 항법 신호보다 광대역이며, 따라서 수신기의 IF 주파수가 높아지며, 수신기의 처리 속도도 빨라져야 한다. 본 연구에서 개발한 수신기의 RF/IF 변환부는 단일 하향 변환기 구조의 디지털 IF 기술로 설계되었으며, IF 주파수는 위성 항법 신호의 최대 대역폭과 표본화 주파수 등을 고려하여 140MHz로 설정하였으며, 표본화 주파수는 112MHz로 설정하였다. RF/IF 변환부의 최종 출력은 디지털 IF 신호로서, IF 신호를 AD 변환기로 처리하여 얻게 된다. 본 연구에서 설계된 위성 항법용 고정밀 수신기 RF 수신단은 - 130 dBm의 입력 신호에 대하여 40dB Hz 이상의 C/N0 특성을 가지며, 40dB 이상의 동적 범위를 갖도록 자동 이득조절 장치가 포함되어 있다.