• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.7
• /
• pp.1350-1357
• /
• 2012

Korean NDGPS, which consists of the ocean-based reference station of 11 site and the land-based reference station of 6 sites, are operating. The land-based reference stations provide the output power of 500W, the service shadow regions are occurred due to mountains and nation topography. In this paper, the service coverages of land-based reference stations are analyzed in the viewpoint of output power enhancements of land-based reference stations within 1KW. Also, we suggest virtual land DGPS reference stations 2 sites to resolve the service shadow regions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2009.06a
• /
• pp.471-474
• /
• 2009

A Hanbitho, which is a ship to measure maritime transportation system, observes and estimates the maritime transportation system and its signal to be able to receive in our closed sea New GNSS systems are constructed such as GLONASS, GALILEO, QZSS, however, our ships can use SBAS service such as MSAS of Japan. So, it is needed to reconstruct new measuring system to observe and estimate new GNSS and SBAS. In this paper, we propose the upgrade method of Hanbiho measuring system.

• Journal of Positioning, Navigation, and Timing
• /
• v.13 no.3
• /
• pp.257-268
• /
• 2024

The Korea Augmentation Satellite System (KASS) satellite was successfully launched and service is being started. By receiving messages transmitted from the KASS satellite, users can employ the messages to improve positioning accuracy or to verify the integrity of Global Positioning System (GPS). In this paper, we propose a test method for a beam-formed GPS receiver developed to improve the survivability of KASS augmented messages that can enhance positioning accuracy even in an environment with jamming or interfering signals. Through the test method proposed in this paper, quantitative verification is performed for a beam-formed GPS receiver aimed at maintaining the augmented navigation solution to which KASS augmented messages are applied by tracking the KASS signal as much as possible under conditions where the jamming signal strength is gradually increasing. In addition, the proposed test method includes three conditions; first, a static lab test method for repeated verification of functions under the same conditions; second, a static outdoor test method for performance verification in an operating environment of a platform equipped with the beam-formed GPS receiver; and finally, a dynamic lab test method for performance verification of a moving platform equipped with the beam-formed GPS receiver toward a jammer. In this paper, we propose a method for simulating the jamming signal incident direction through the phase delay of an RF cable designed to prevent unintentional jamming signal emission in both lab and outdoor tests, and a method of applying test software for injecting a jamming signal to compare the survivability performance consistently according to the presence or absence of beamforming signal processing. Through the proposed test method, it was verified that the augmented navigation solution could be output for a longer time period when the beamforming signal processing was applied to the KASS satellite signal in the beam-formed GPS receiver.

• The KIPS Transactions:PartD
• /
• v.9D no.1
• /
• pp.127-134
• /
• 2002

GPS is one of today's most widely used surveying techniques. But, users can't acquire an enough accuracy in applications of the navigation or geodesy by the GPS positioning technique because of the effects of the ionosphere and troposphere and US DoD's systematic errors. The solution of these restrictions is the DGPS technique that is to eliminate the common errors and can achieve a high accuracy. Although of sufficient density for good DGPS, accuracy of positioning is just not dense enough to provide complete coverage for real-time positioning, because distances between base and rover is short. In this paper, we designed and implemened a RTK-GPS error correction signal transmission system for long-distance using the TCP/IP, which consist of TCP, UDP and IP, which allows a user to increase the distance at which the rover receiver is located from the base, due to radio modem.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.2
• /
• pp.97-104
• /
• 2015

Due to the introduction of various IT devices, including the recently smartphones and the widespread use of the car navigation system to the location-based information service space has been increased. Spatial information users have been requiring higher levels of quality. In this paper, we study how to build accurate three-dimensional space information by integrating MMS(Moblie Mapping System) survey and airborne survey data. Thus, to analyze the tendency of deviation between the MMS survey and airborne survey data observed in the experimental region, the deviation tendency of the data, it was confirmed that was not consistent. Deviation correction model to select how to change the georeferencing information directly contained in the GPS/INS processing results for the determination, classifies the standard is a method for acquiring the correction reference point coordinates using the calibration model, and analyzed their advantages and disadvantages. With the information of the reference point obtained by airborne photograph of a project, using the method of correcting the MMS survey data. Not only clear the deviation existing between the MMS survey data, it was possible to confirm that the deviation exists between the airborne survey data and MMS survey data was also almost erased.

• Proceedings of the IEEK Conference
• /
• 2003.07c
• /
• pp.2521-2524
• /
• 2003

Since inertial sensor errors which increase with time are caused by initial orientation error and sensor errors (accelerometer bias and gyro drift bias), the accuracy of these devices, while still improving, is not adequate for many of today's high-precision, long-duration sea, aircraft, and long-range missile missions. This paper presents a navigation error compensation scheme for Strap-Down Inertial Navigation System (SDINS) using Line-Of-Sight(LOS) vector from star sensor. To be specific, SDINS error model and measurement equation are derived, and Kalman filter is implemented. Simulation results show the bounded-ness of position and attitude errors.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.18 no.2
• /
• pp.1-8
• /
• 2010

In order to determine the possibility of using NDGPS signals for flight operations, in-flight measurements of signals transmitted from various ground reference stations(RS) were conducted along the air routes of South Korea. Signal strength and signal to noise ratio(SNR) data were collected along domestic flight routes and recorded with time. By using three-dimensional geographical position data of the aircraft, signal strength data of en-route position were calculated and used to obtain scatter-plot of signal strength. These results were used to outline the effective coverage and field strength hemispheres of the selected DGPS signals.

• Bulletin of the Korean Space Science Society
• /
• 2011.04a
• /
• pp.22.3-22.3
• /
• 2011

최근 일본 동북부 지역에서 리히터 규모 9.0의 대지진이 발생하였으며, 이로 인하여 일본 본토 및 주변지역의 지각 이동이 관측되고 있다. 한반도의 경우 일본에 비해 지진에 비교적 안정적이라고 알려져 있으나 활성단층대가 존재하고 리히터 규모 3.5이하의 지진이 년간 30~40여 차례 발생하고 있다. 이 논문에서는 위성항법기반 재난/재해 감지 연구의 일환으로써 일본 대지진이 한반도 지각 이동에 미치는 영향을 분석하였다. 현재 국내에는 100여개의 GPS 상시관측소가 운영되고 있으며, 다양한 선행 연구를 통해 동남쪽 방향으로 2~3cm/yr 속도로 이동하고 있는 것으로 알려져 있다. 이 논문에서는 이러한 선행 연구 결과를 바탕으로 일본 지진 발생 전후의 국내 GPS 상시관측소 좌표 변동량을 분석하였다. GPS 자료 처리를 위하여 GIPSY-OASIS 5.0을 이용하였으며, 안테나 위상중심변동량(phase center variation), 해수조석하중(Ocean tidal loading)에 의한 지각변동량을 보정하였다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.3
• /
• pp.306-314
• /
• 2012

This paper proposes a new system to maximize efficiency of Air Base Protection Operations through the development of location identification software. The Wibro-based location identification system for Air Base Protection Force offers Blue Ground Force digitalized character message which is not exposed to enemy. Also, it is possible to automatically provide the location of Blue Ground Force to Air Base Ground Operations Center. The test result proves that this system is very helpful when Air Base Protection Force executes Air Base Protection Operations.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.12
• /
• pp.61-67
• /
• 2005

This paper presents the carrier phase DGPS method providing a stable navigation solution under the condition of frequent blockage of the GPS signals. The proposed algorithm reject the channels having large errors using a clock bias drift and then calculated the more accurate solution. By investigating the relation between visible satellites` elevation and their clock bias drift, a proper threshold is set. Simulation shows that the presented result is as good as that of commercial system with real data.