• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.82-90
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• 2011

This paper proposes an advanced outdoor localization algorithm of a GPS(global positioning system)-INS(inertial navigation system) integration system. In order to reduce noise from the internal INS sensors, discrete wavelet transform and variable threshold method are utilized. The UPF (unscented particle filter) combines GPS information and INS signals to implement precise outdoor localization algorithm and to reduce noise caused by the acceleration, deceleration, and unexpected slips. The conventional de-noising method is mainly carried out using a low pass filter and a high pass filter which essentially result in signal distortions. This newly proposed system utilizes the vibration information of actuator according to fluctuations of the velocity to minimize signal distortions. The UPF also resolves non-linearities of the actuator and non-normal distributions of noises. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• Journal of Aerospace System Engineering
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• v.4 no.3
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• pp.17-23
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• 2010

GPS sensors provide accurate position and velocity of moving vehicles. However, GPS is weak at intermittent signal loss and large position error. Combination with INS improves the GPS position accuracy during the GPS signal loss. In this paper, a fusion filter using GPS and INS is developed and its perfomance is analyzed with RC car and RC airplane experiments.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.3
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• pp.341-353
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• 2024

This paper presents the design results of a Multi-band Global Positioning System (GPS)/Korean Positioning System (KPS) Real-Time Kinematics (RTK) precise positioning simulator and evaluate its functionalities. The designed simulator consists of a trajectory generation module, a Radio Frequency (RF) signal generation module, a RF signal reception module, a coarse positioning module, a precise positioning module, and an error statistics reporting module. Simulations in realistic scenarios confirm that the proposed baseband simulator works appropriately. The developed simulator can adjust the type, number, band, and Pseudo Random Noise (PRN) code type of the satellite constellation in various ways, and the practical positioning performance can be tested. It can also reflect the channel influence at the actual RF stage and the influence during the initial synchronization and tracking process. Considering such advantages, the proposed simulator would be useful in future researches and developments related to KPS.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.46-53
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• 2010

In this paper, we explained status and development trend of GNSS (Global Navigation Satellite System): GPS (Global Satellite System) of US, GLONASS (Global Navigation Satellite System) of Russia, Galileo of EU, Beidou/Compass of China, and QZSS (Quasi-Zenith Satellite System) of Japan). System construction and operation status of five GNSS systems were summarized. In addition, development plan and modernization of these systems were explained.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.818-826
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• 2002

Since multipath phenomenon frequently occurs when a Global Positioning System receiver is placed in urban area crowded with large buildings, efficient mitigation of multipath effects is necessary to resolve. In this paper, we propose a new multipath detection technique that is useful in real-time positioning with a general Global Positioning System receiver. The proposed technique is based on a channelwise multipath test statistic that efficiently indicates the degree of fluctuations induced by multipath error. The proposed multipath test statistic is operationally advantageous because it does not require any specialized hardware nor any pre-computation of receiver position, it is directly related to standard $\chi$$^2$-distributions, and it can adjust the detection resolution by increasing the number of successive measurements. Simulation and experiment results verify the performance of the proposed multipath detection technique.

• Journal of Astronomy and Space Sciences
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• v.30 no.3
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• pp.207-212
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• 2013

Ionosphere is one of the largest error sources when the navigational signals produced by Global Positioning System (GPS) satellites are transmitted. Therefore it is very important to estimate total electron contents (TEC) in ionosphere precisely for navigation, precise positioning and some other applications. When we provide ionospheric TEC values in real-time, its application can be expanded to other areas. In this study we have used data obtained from nine Global Navigation Satellite System (GNSS) reference stations which have been operated by Korea Astronomy and Space Science Institute (KASI) to detect ionospheric TEC over South Korea in real-time. We performed data processing that covers converting 1Hz raw data delivered from GNSS reference stations to Receiver INdependent Exchange (RINEX) format files at intervals of 5 minutes. We also analyzed the elevation angles of GPS satellites, vertical TEC (VTEC) values and their changes.

• Journal of Astronomy and Space Sciences
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• v.27 no.2
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• pp.123-128
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• 2010

This paper analyzes that the global positioning system (GPS) receiver differential code bias (DCB) has effect on the estimation the ionosphere total electron content (TEC). The data from nine permanent GPS sites of the Korea Astronomy and Space Science Institute (KASI) were used for the estimation of the receiver DCB before (Trimble 4000 SSi) and after (Trimble NetRS) the receiver replacement, using the singular value decomposition method. The results showed that the estimated mean value of the receiver DCB varied from 0.11 ns (nanosecond) to 7.54 ns before the receiver replacement, but the receiver DCBs shoed large values than 20 ns except some stations after the replacement. The receiver DCB showed a relatively large difference by types of the receivers, and, as a result, it had a great effect on the estimation the ionosphere TEC using GPS.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.415-416
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• 2017

본 논문은 사용자가 관광지의 어떤 관심지점에 근접했는지 사용자에게 능동적으로 알려주는 안드로이드 앱을 소개한다. 안드로이드는 관심지점에 근접했을 경우에 알람메시지를 발생하는 개발자를 위한 함수를 제공한다. 또한 GPS(Global Positioning System) 신호나 네트워크 신호를 이용하여 현재 위치를 알려주는 함수도 제공한다. 본 논문은 안드로이드가 제공하는 개발자를 위한 함수들을 이용하여 여러 가지 방법으로 관심지점 근접 상황을 인지하는 프로그램을 구현하고 이들 간의 성능을 비교한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.2
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• pp.101-108
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• 2005

Inertial Navigation System has been used extensively to determine the position, velocity and attitude of the body. An INS is very expensive, however, heavy, power intensive, requires long setting times and the accuracy of the system is degraded as time passed due to the accumulated error. Global Positioning System(GPS) receivers can compensate for the Inertial Navigation System with the ability to provide both absolute position and attitude. This study describes a method to improve both the accuracy of a body positioning and the precision of an attitude determination using GPS antenna array. Existing attitude determination methods using low-cost GPS receivers focused on the relative vectors between the master and the slave antennas. Then the positioning of the master antenna is determined in meter-level because the single point positioning with pseudorange measurements is used. To obtain a better positioning accuracy of the body in this research, a wireless internet is used as an alternative data link for the real-time differential corrections and dual-frequency GPS receivers which is expected to be inexpensive was used. The numerical results show that this system has the centimeter level accuracy in positioning and the degree level accuracy in attitude.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.3
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• pp.119-129
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• 2016

This paper presents an integrated navigation system for accurate navigation solution-based safety and convenience services in the vehicular augmented reality (AR)-head up display (HUD) system. For lane-level guidance service, especially, an accurate navigation system is essential. To achieve this, an inertial navigation system (INS)/global positioning system (GPS)/vision/digital map (IGVM) integrated navigation system has been developing. In this paper, the concept of the integrated navigation system is introduced and is implemented based on a multi-model switching filter and vehicle status decided by using the GPS data and inertial measurement unit (IMU) measurements. The performance of the implemented navigation system is verified experimentally.