• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.72-78
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• 2007

Determination of the local vertical is not trivial for a moving vehicle and in general will require corrections for the Earth geophysical deflection. The vehicle's local vertical can be estimated by INS integration with initial alignment in SDINS(Strap Down INS) system. In general, the INS has drift error and it cause the performance degradation. In order to compensate the drift error, GPS/INS augmented system is widely used. And in the event that GPS is denied or unavailable, celestial navigation using star tracker can be a backup navigation system especially for the military purpose. In this celestial navigation system, the vehicle's position determination can be achieved using more than two star trackers, and the accuracy of position highly depends on accuracy of local vertical direction. Modern tilt sensors or accelerometers are sensitive to the direction of gravity to arc second(or better) precision. The local gravity provides the direction orthogonal to the geoid and, appropriately corrected, toward the center of the Earth. In this paper the relationship between direction of center of the Earth and actual gravity direction caused by geophysical deflection was analyzed by using precision orbit simulation program embedded the JGM-3 geoid model. And the result was verified and evaluated with mathematical gravity vector model derived from gravitational potential of the Earth. And also for application purpose, the performance variation of pure INS navigation system was analyzed by applying precise gravity model.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.02a
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• pp.82-94
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• 2004

This paper addresses solutions to the challenges of carrier phase integer ambiguity resolution and cycle slip detection/identification, for maintaining high accuracy of an integrated GPS/Pseudolite/INS system. Such a hybrid positioning and navigation system is an augmentation of standard GPS/INS systems in localized areas. To achieve the goal of high accuracy, the carrier phase measurements with correctly estimated integer ambiguities must be utilized to update the system integration filter's states. The occurrence of a cycle slip that is undetected is, however, can significantly degrade the filter's performance. This contribution presents an effective approach to increase the reliability and speed of integer ambiguity resolution through using pseudolite and INS measurements, with special emphasis on reducing the ambiguity search space. In addition, an algorithm which can effectively detect and correct the cycle slips is described as well. The algorithm utilizes additional position information provided by the INS, and applies a statistical technique known as the cumulative-sum (CUSUM) test that is very sensitive to abrupt changes of mean values. Results of simulation studies and field tests indicate that the algorithms are performed pretty well, so that the accuracy and performance of the integrated system can be maintained, even if cycle slips exist in the raw GPS measurements.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.67.2-67
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• 1998

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.381-388
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• 2008

In the common practice of air-photographing measurement aerial-photogrammetric, the location of camera at the time of photographing is identified by performing aerotriangulation. However, installing ground-base station to enable aerotriangulation takes majority portion of a map making cost. Aerial-photogrammetric has shown a great improvement helped by steady upgrading in equipment and development in quantitative study. Aerotriangulation can be replaced by Direct Georeferencing, which uses GPS/INS to identify a camera location and to produce detailed information. An innovative technique replacing aerotriangulation, it has a disadvantage that base station has to be available in the area of photographing. The study intends to suggest a method applying VRS in GPS/INS aerotriangulation. Despite the fact that Direct Georeferencing is the innovated technique which substitutes existing aerotriangulation, it still need to install the ground-base station in GPS/INS aerotriangulation. GPS/INS data was analyzed with 4 different cases in order to accomplish the purpose of this study. In addition, in the thesis, it was approved that VRS can be utilized to make small-scale map as accurate as base station. This study is expected to improve the efficiency of work by showing that VRS can be used not only in base station but also enabling base station in the ground-access challenging area.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1060-1065
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• 2003

To determine whether dietary fatty acids affect pancreatic $\beta$-cell function, the INS-1 $\beta$-cells and the pancreatic islets isolated from Zucker obese (fa/fa) rats were cultured with stearic acid and conjugated linoleic acid (CLA). As a result, DNA fragmentation laddering was substantially decreased in the INS-1 $\beta$-cells and the isolated pancreatic islets cultured with 2 mM CLA compared to those cultured with stearic acid. To investigate the mechanism by which CLA alleviates cell apoptosis under DNA fragmentation assay, we examined mRNA expressions of apoptosis-related proteins including Bax and Bcl-2 associated with cell death agonist and antagonist, respectively, in both INS-1 cells and islets cultured with 2 mM fatty acids. Bax mRNA expression was not altered by either stearic acid or CLA, whereas Bcl-2 mRNA expression was enhanced by CLA when compared to the stearic acid cultures. However, there were no changes in cell apoptosis and apoptotic-regulating gene products in either INS-1 cells or isolated islets treated with or without 2 mM CLA. It is concluded that CLA maintains $\beta$-cell viability via increased Bcl-2 expression compared to the stearic acid cultures, which may help to alleviate, at least somewhat, the onset of NIDDM in the physiological status. More detailed study is still needed to elucidate the effect of CLA on the prevention of fatty acid-induced $\beta$-cell apoptosis.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.706-711
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• 2008

This paper is presented an accurate localization scheme for mobile robots based on the fusion of ultrasonic satellite (U-SAT) with inertial navigation system (INS), i.e., sensor fusion. Our aim is to achieve enough accuracy less than 100 mm. The INS consist of a yaw gyro, two wheel-encoders. And the U-SAT consist of four transmitters, a receiver. Besides the localization method in this paper fuse these in an extended Kalman filter. The performance of the localization is verified by simulation and two actual data(straight, curve) gathered from about 0.5 m/s of driving actual driving data. localization methods used are general sensor fusion and sensor fusion through Kalman filter using data from INS. Through the simulation and actual data studies, the experiment show the effectiveness of the proposed method for autonomous mobile robots.

• 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.

• The KIPS Transactions:PartB
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• v.14B no.3 s.113
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• pp.163-170
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• 2007

In autonomous navigation of a mobile vehicle or a mobile robot, localization calculated from recognizing its environment is most important factor. Generally, we can determine position and pose of a camera equipped mobile vehicle or mobile robot using INS and GPS but, in this case, we must use enough known ground landmark for accurate localization. hi contrast with homography method to calculate position and pose of a camera by only using the relation of two dimensional feature point between two frames, in this paper, we propose a method to calculate the position and the pose of a camera using relation between the location to predict through perspective transform of 3D feature points obtained by overlaying 3D model with previous frame using GPS and INS input and the location of corresponding feature point calculated using KLT tracking method in current frame. For the purpose of the performance evaluation, we use wireless-controlled vehicle mounted CCD camera, GPS and INS, and performed the test to calculate the location and the rotation angle of the camera with the video sequence stream obtained at 15Hz frame rate.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.221-227
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• 2019

In this paper, interacting multiple model (IMM) filter was designed that guarantees a stable navigation performance even in the unstable satellite navigation position. In order to design IMM filter in INS / GPS integrated navigation system, sub filter of the IMM filter is defined as Kalman filter. In the IMM filter configuration, two subfilters are determined. Each Kalman filter defines the six-teenth state composed of position, velocity, attitude, and sensor error from the INS error equation and the states additionally derived in case of the coloured measurement noise. In order to verify the performance of the proposed filter, we compared the performance how the filter works in the presence of arbitrary error in GPS navigation solution. The Monte Carlo simulation was performed 100 times and the results were compared with the root mean square(RMS). The results show that the proposed method is stable against errors and show fast convergence.

• American Studies
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• v.44 no.2
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• pp.67-96
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• 2021

The Canadian public broadcaster CBC had successfully aired a sitcom centered on a Korean immigrant family from 2016 to 2021. The show is based on the play Kim's Convenience written by a Korean-Canadian playwright Ins Choi. This study explores literary features of Kim's Convenience that accounts for its popularity; three elements of the show play crucial roles in maintaining the balance between specificity and universality. First, Choi deploys a Korean immigrant story in the form of comedy. Second, the main plot revolves around an ordinary family with generational strains that ends in reconciliation. Third. the Kims are depicted more as an archetypical family than a stereotypically Asian one. By closely interweaving these elements, Choi induces the audience to find commonalities from the show, and racial specificities of the Kim's family become "spicy" attractions of the play.