• Journal of Positioning, Navigation, and Timing
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• 제4권3호
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• pp.141-150
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• 2015

In this study, a Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) / odometer / barometer integrated navigation system that uses a commercial navigation device including Micro Electro Mechanical Systems (MEMS) accelerometer and gyroscope in addition to GNSS, odometer information obtained from a vehicle, and a separate MEMS barometer sensor was implemented, and the performance was verified. In the case of GNSS and GNSS/INS integrated navigation system that are generally used in a navigation device, the performance would deteriorate in areas where GNSS signals are not available. Therefore, an integrated navigation system that calculates a better navigation solution in areas where GNSS signals are not available compared to general GNSS/INS by correcting the velocity error of GNSS/INS using an odometer and by correcting the cumulative altitude error of GNSS/INS using a barometer was suggested. To verify the performance of the navigation system, a commercial navigation device (Softman, Hyundai Mnsoft, http://www.hyundai-mnsoft.com) and a barometer sensor (ST Company) were installed at a vehicle, and an actual driving test was performed. To examine the performance of the algorithm, the navigation solutions of general GNSS/INS and the GNSS/INS/odometer/barometer integrated navigation system were compared in an area where GNSS signals are not available. As a result, a navigation solution that has a smaller position error than that of GNSS/INS could be obtained in the area where GNSS signals are not available.

• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.93-102
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• 2024

Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS) integrated navigation systems provide highly accurate and reliable navigation solutions and are widely used as civil and military navigation systems. In order to facilitate the GNSS/INS integrated navigation system development task, a simulator can be used to provide inputs for the GNSS/INS integrated navigation system. In this paper, a simulator design using general-purpose Personal Computer (PC) and Off-The-Shelf (OTS) interface boards for a GNSS/INS integrated navigation system is proposed and implementation results are presented. Requirements of the GNSS/INS integrated navigation system simulator are presented and a design method that satisfies the requirements is described. In order to show the usefulness of the proposed design method, a simulator using a general-purpose PC and OTS interface boards for the GPS/INS integrated navigation system are implemented and verified. The implementation results show that the simulator designed by the proposed method generates the GPS L1 C/A signal and IMU data without any problems.

• 대한임베디드공학회논문지
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• 제17권4호
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• pp.239-247
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• 2022

The existing studies on the localization in the GNSS (Global Navigation Satellite System) denied environment usually exploit low-cost MEMS IMU (Micro Electro Mechanical Systems Inertial Measurement Unit) sensors to replace the GNSS signals. However, the navigation system still requires GNSS signals for the normal environment. This paper presents an integrated GNSS/INS (Inertial Navigation System) navigation system which combines GNSS and multiple IMU sensors using extended Kalman filter in partially GNSS-denied environments. The position and velocity of the INS and GNSS are used as the inputs to the integrated navigation system. The Mahalanobis distance is used for novelty detection to detect the outlier of GNSS measurements. When the abnormality is detected in GNSS signals, GNSS data is excluded from the fusion process. The performance of the proposed method is evaluated using MATLAB/Simulink. The simulation results show that the proposed algorithm can achieve a higher degree of positioning accuracy in the partially GNSS-denied environment.

• 한국군사과학기술학회지
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• 제22권2호
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• pp.197-206
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• 2019

Safe aircraft requires highly reliable navigation information. The traditionally used inertial navigation system (INS) often displays faulty location information due to its innate errors. To overcome this, the INS/GNSS or INS/TRN integrated navigation can be used. However, GNSS is vulnerable to jamming and spoofing, while TRN can be degraded in the flat and repetitive terrains. In this paper, to improve the performance and ensure the high reliability of the navigation system, the INS/GNSS/TRN integrated navigation based on federated filter is designed. Master filter of the integrated navigation uses the estimates and covariances of two local filters - INS/GNSS and INS/TRN integrated filters. The local filters are designed with the EKF that is feedforward type and composed of the 17st state variables. And the INS/GNSS integrated navigation includes the barometer error compensation method. Finally, the proposed INS/GNSS/TRN integrated navigation is verified by vehicle and captive flight tests.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.967-976
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• 2016

This paper presents a 3D carrier-smoothed GNSS/DR (Global Navigation Satellite System/Dead Reckoning) integrated system for precise ground-vehicle trajectory estimation. For precise DR navigation on sloping roads, the AHRS (Attitude Heading Reference System) methodology is employed. By combining the integrated carrier phase of GNSS and DR sensor measurements, a vehicle trajectory with an accuracy of less than 20cm is obtained even when cycle slip or change of visibility occur. In order to supplement the weak GNSS environment with DR successfully, the DR sensor is precisely compensated for using GNSS Doppler measurements when GNSS visibility is good. By integrating a multi-GNSS receiver with low-cost IMU, a precise 3D navigation system for land vehicles is proposed in this paper. For real-time implementation, a decoupled Kalman filter is employed in the integrated system. Through field experiments, the performance of the proposed system is verified in various road environments, including sloping roads, good-visibility areas, high multi-path areas, and under-ground parking areas.

• 한국측량학회지
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• 제27권6호
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• pp.659-667
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• 2009

이 연구에서는 3차원 건물좌표를 이용한 통합 GNSS 시뮬레이터 IGSS(Inha GNSS Simulation System)를 개발하고 정확도를 검증하였다. 또한 IGSS를 이용하여 통합 GNSS 환경에서의 측위 가용성 및 정확도 향상을 평가하였다. GPS와 GLONASS의 예측결과를 실제관측 결과와 비교하여 시뮬레이터를 검증하였으며 그 결과, GPS와 GLONASS의 오차 발생빈도가 각각 6.4%와 7.5%로 나타났다. 통합 GNSS 환경에서의 측위 가용성과 정확도 향상에 관한 평가는 중고층 건물에 의한 신호차폐현상이 심한 정부대전청사를 대상으로 하였다. GPS를 단독으로 사용하였을 경우, GPS와 GLONASS를 동시에 사용하였을 경우, GPS, GLONASS, 그리고 Galileo를 함께 사용하였을 경우를 구분하여 가시위성의 개수와 정밀도 저하율을 산출하고 그 결과를 비교 및 평가하였다.

• 한국측량학회지
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• 제25권3호
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• pp.231-238
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• 2007

본 연구에서는 가까운 장래에 실현될 GNSS(Global Navigation Positioning System) 결합측위의 가용성을 평가하기 위하여, GPS(Global Positioning System), Galileo 및 QZSS(Quasi-Zenith Satellites System)의 직달파(direct signal), 반사파(reflected signal), 회절파(diffracted signal) 식별을 위한 신호 전달 모형을 수립하고 이를 3차원 지리정보시스템과 결합함으로써, 위성 가시도와 측위 오차 요소를 모사 측정하였다. 중고층 빌딩이 밀집한 일본 동경도청 부근의 $1km{\times}1km$ 구역을 40,000개의 $5m{\times}5m$ 격자로 구획하여 실시한 시뮬레이션을 통해, GPS 측위와 GNSS 결합측위에 있어서 가시위성의 개수, 위성 고도, 정밀도 저하율(dilution of position : DOP), 의사거리 다중 경로 오차(pseudorange multipath error : PME)를 비교 평가하였다. GNSS 결합측위에서는 가시위성 및 직달파 위성의 개수가 현격히 증가함을 확인할 수 있었으며, 위성고도의 평균은 GPS 측위에서보다 약간 낮게 나타나지만, 위성들의 기하학적 배치가 양호하게 이루어져 정밀도 저하율이 매우 감소함을 알 수 있다. 고밀도 도시공간에서는 빌딩 등의 전파 반사로 인해 발생하는 의사거리 다중경로 오차를 완화하는 것이 사용자 위치 정확도를 향상시키기 위한 핵심적인 요소이므로, 수신기 안테나의 설계 및 배치, 신호처리 및 공간통계 기법 등을 GNSS 결합측위에 적합하도록 개선하는 것이 필요할 것이다.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.279-286
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• 2022

In this paper, we designed a software library that produces integrated Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) navigation information using the raw measurements provided by the GNSS chipset, gyroscope, accelerometer and magnetometer embedded in android smartphone. Loosely coupled integration method was used to derive information of GNSS /INS integrated navigation. An application built in the designed library was developed and installed on the android smartphone. And we conducted field experiments. GNSS navigation messages were collected in the Radio Technical Commission for Maritime Service (RTCM 3.0) format by the Network Transport of RTCM via Internet Protocol (NTRIP). As a result of experiments, it was confirmed that design requirements were satisfied by deriving navigation such as three-dimensional position and speed, course over ground (COG), speed over ground (SOG), heading and protection level (PL) using the designed library. In addition, the results of this experiment are expected to be applicable to maritime navigation applications using smart device.

• ETRI Journal
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• 제38권6호
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• pp.1172-1178
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• 2016

The atmospheric meteorology parameters of the earth, such as temperature, pressure, and humidity, strongly influence the propagation of signals in Global Navigation Satellite Systems (GNSSs). The propagation delays associated with GNSS signals can be modeled and explained based on the atmospheric temperature, pressure, and humidity, as well as the locations of the satellites and receivers. In this paper, we propose an optimized and simplified low cost GNSS base weather station that can be used to provide a global estimate of the integrated water vapor value. Our algorithm can be used to measure the zenith tropospheric delay based on the measured propagation delays in the received signals. We also present the results of the data measurements performed at our station located in the Tlemcen region of Algeria.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 추계학술대회
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• pp.73-74
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• 2019

eLoran과 GNSS를 통합하여 항법을 수행하는 수신기를 개발하고 있다. 현재 Loran-C 단독 항법의 경우 LORADD 수신기와 유사한 성능을 보이고 있고, GNSS 항법의 경우 GPS만 사용하는 LORADD 수신기에 비해 GPS+GLONASS 또는 GPS+BDS를 사용하기 때문에 더 높은 GNSS 항법 성능을 갖는다. 추후 시각이 동기화되고 TOA를 구할 수 있는 eLoran/GNSS 통합 항법에서 LORADD 수신기에 비해 우수한 성능을 기대할 수 있고, 이를 위해 현재 Loran 데이터 채널 복호화 기능과 간섭 등 오차 요인을 제거하는 기능을 구현 중이다.