• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.141.5-141
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• 2001

An attitude GPS receiver with 3 antennas obtains 3-dimensional attitude using GPS carrier phase measurement INS obtains the 3 dimensional navigation solution for IMU consisting of accelerometers and gyro. Ground-alignment process for the low -cost INS cannot be performed well due to the large sensor noise. Using the standard GPS receiver, however, continuous in-flight alignment for the INS becomes possible, and consequently, the errors in IMU sensors and navigation solution can be compensated. Especially with attitude measurement from the attitude GPS receiver, the compensation of errors in gyroscope and attitude would be done respite of the vehicle´s dynamics and their error covariance would be reduced. This paper presents ...

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.94-94
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• 2000

In this paper, the performance of INS/GPS integration is analyzed. Generally the integration method is classified into two method. One is loosely coupled integration, Another is tightly coupled integration. For the simulation, the error model of Kalman fitter is defined and the result of simulation is analyzed. When the number of visible satellites is less than four, the error of tightly coupled integration is smaller than that of loosely coupled integration. To very the result of simulation, van test that use LP-81 IMU and Millen3151R GPS receiver is carried out.

• Korean Journal of Geomatics
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• v.2 no.2
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• pp.99-105
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• 2002

The accuracy of the Digital Photologging System, designed for the construction of the road Facility Database, highly depends on the positions and attitudes of the cameras from GPS/INS integration. In this paper, the development of a loosely coupled GPS/INS is presented. The performance of the system is verified through a simulation as well as a real test data processing. Since the IMU used in this study shows large systematic errors, the possible accuracy of the positions and attitudes of this low-performance IMU when combined with precise GPS positions are assigned. Currently, the integrated system shows the positional accuracy better than 5cm in real data processing. Although the accuracy of attitude based on real test could not be assigned at this time, it is expected that better than 0.5 degrees and 1.8 degrees for horizontal and down component are achievable according to the simulation result.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.140-148
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• 2000

This paper presents a fault detection and isolation(FDI) method based on Generalized Likelihood Ratio(GLR) test for the tightly coupled SDINS/CPS system. The GLR test is known to have the capability of detecting an assumed change while estimating its occurrence time and magnitude, and isolating the changing part. Once a fault is detected even if we don't know if the fault occurrs at either INS or GPS, multi-hypothesized GLR scheme performs the fault isolation between INS and GPS, and find which satellite malfunctions. However, in the INS faulty case, it turned out to fail to accomodate the fault isolation between accelerometer and gyroscope due to the coupling effects and a poor observability of the system. Hence, to isolate the INS fault, it needs to change the attitude of the vehicle resulting in enhancing the degree of observability.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2433-2435
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• 2000

Inertial Navigation System(INS) provides short-term accurate navigation solution but its error grows with time due to integration characteristics. Meanwhile, Global Positioning System(GPS) provides long-term stable solution but it has poor error characteristics in high dynamic region. So for its synergistic relationship, an integrated INS/GPS systems has been widely used as an advanced navigation system. Generally, two kinds of integration method are used. One is loosely coupled mode which uses GPS-derived position and velocity as measurements in an integrated Kalman filter. The other is tightly coupled one which uses pseudorange and pseudorange rate as Kalman filter measurements. In this paper the system error models and observation models for two kinds of integrated systems are derived, respectively, and their performance are compared through Monte-Carlo simulations.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.31-41
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• 2005

In order to carry out aerial photogrammetry using GPS/INS, it is necessary to apply exterior orientation parameters, obtained while making a photo, to the editing process. It should be noted that the verification process of aerial mapping result is the most crucial process at the GPS/INS based digital photogrammetry. To this end, this study has compared the mapping result by the ways of AT results, plotter, and orientation, which is from basis of the Analytical raw map produced by the existing AT results. When comparing the horizontal and vertical accuracy of the analytical mapping with that of digital restitution, it could be found that the latter is more accurate than that of the former. In addition, it was reveled that the horizontal error was bigger than that of vertical one. Even though the accuracy of the GPS/INS based AT Direct orientation was three times poorer than the of indirect one, it was recognized that the photogrammetry process was effectively performed in the application of scale 1:5000 mapping with satisfying the allowance errors.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.112-119
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• 2004

This paper proposes an attitude determination GPS/INS integrated system scheme for a UAV and presents experimental flight test results. The proposed system is designed as a part of an autopilot system and comprises a GPS attitude determination receiver, an off-the-shelf inertial measurement unit (IMU), and a navigation computer unit (NCU). UAV requires accurate attitude information for stable automatic flight control. The proposed system can provide accurate attitude information for the flight control computer (FCC) so that stable automatic flight control can be achieved. In order to verify the performance of the proposed scheme, an integrated navigation system has been developed. In order to evaluate the developed navigation system, the flight test has been performed. In the flight test, the developed system was shown to provide the position, the velocity and the attitude satisfactorily enough for stable flight control. The accuracy of the attitude information of the developed system was confirmed by comparing attitude of vertical gyro.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.8
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• pp.717-725
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• 2005

The adaptive filter is proposed for the INS/GPS. The proposed filter can estimate the variance of the process noise using the residual of the filter. To verify the efficiency of the adaptive filter, it is applied to the loosely-coupled INS/CPS that employs the additive quaternion error model. Simulation results demonstrate that the proposed filter is more effective in estimating the attitude error than EKF.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.4_1
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• pp.293-298
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• 2014

Recently, the direct georeferencing has been becoming a common method in the aerial photogrammetry. As this direct georeferencing method using converged sensor of the digital photogrammetry camera and GPS(Global Positioning System)/INS(Inertial navaigation System), more rapid and accurate aerial photogrammetry has improved following advanced performance in photogrammetry. Since the accuracy of EO parameters from the direct georeferencing is determined by GPS/INS accuracy, it is significant to calculate the exact attitude information using values of INS rotations. For following calculations, the misalignment, such as INS rotation and the gap of GPS/INS, has to be decided. Because the number of ground control points are used for tirangulation and boresight calibration, those results should be different according to array and location of ground control points. In the study, those location and array of ground control points were tested to be used boresight calibration. As a result, there is no significant change of misalignment and exterior orienation parameters in the case when ground control points were at all course. On the contrarily, the difference has been shown in the case of no ground control point at course.

• International Journal of Aeronautical and Space Sciences
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• v.2 no.1
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• pp.67-77
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• 2001

In recent navigation system, the profitable solution is to integrate the GPS and Stapdwon INS (SDINS) system and its integration allows compensation for shortcomings of each system. This paper describes the hardware preparation and presents the test results obtained from the automobile test of the developed system. The automobile tests was conducted with two kinds of inertial sensors and GPS receivers : short range and middle range test, to verify and evaluate the performance of the integrated navigation system. The reference of position is given by the Differential GPS(DGPS) which has cm-level accuracy to compare the accuracy of system. Kalman filtering is used for integrating GPS and SDINS and this filter effectively allows the long-term stability of GPS to correct and decrease the time deviation error of SDINS.