• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.123-127
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• 2004

Nowadays it is necessary to manage the road system effectively because of the explosive increment of vehicles and goods. To resolve this problems through the fast upgrade of information about position and time of moving vehicles, the combined navigation system using GPS(Global Positioning System) and complementary navigation system, i.e. INS(Inertial Navigation System), DR(Dead Rocking), etc. has been used. Although GPS is popular for the vehicles in the urban canyon because of its few satellites. In this paper, position tracking algorithm is presented, which reduces vehicle position error dramatically by fusing GPS and INS sensors. And the validity of our algorithm is demonstrated by the experimental results with the real car.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.106-110
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• 2002

4S-Van is being developed in order to provide the spatial data rapidly and accurately. 4S-Van technique is a system for spatial data construction that is heart of 4S technique. Architecture of 4S-Van system consists of hardware integration part and post-processing part. Hardware part has GPS, INS, color CCD, camera, B/W CCD camera, infrared rays camera, and laser. Software part has GPS/INS integration algorithm, coordinate conversion, lens correction, camera orientation correction, and three dimension position production. In this paper, we suggest that adequate 4S-Van design is needed according to application environment from various test results.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.103-106
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• 2004

Nowadays it is necessary to manage the road system effectively because of the explosive increment of vehicle and goods. To resolve this problems through the fast upgrade of information about position and time of moving vehicle, the combined navigation system using GPS and complementary navigation system, i.e. INS, DR, etc. has been used. Although GPS is popular for the vehicle navigation system, this is not useful for the kinematic positioning of the vehicles in the urban canyon because of its few satellites. Therefore, this study deals with the kinematic positioning of the vehicles with GPS CORS to GPS navigation. For this, first the static single point positioning of GPS and GPS for reference station was performed to evaluate the accuracy of GPS positioning. Next, in the post-processed, the DGPS (Differential GPS) was performed for the kinematic positioning of the vehicles. So, it is expected that GPS CORS can be applicable to the control of traffic flow, the effective management of road system, and the development of ITS and it is regarded that the combined navigation system of vehicles with GPS, INS, and DR, etc. should be studied constantly.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.105-116
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• 2006

This research introduces the method to measure cross-slope using Road Safety Survey and Analysis Vehicle(RoSSAV) with multiple sensors. Cross-slope is an important element like horizontal alignment and vertical alignment in evaluating safety of the roads. In many cases, cross-slope is different from drawings due to frequent overlays. It is extremely difficult to measure cross slope at the roads which has huge traffic volume. Therefore, the algorithm, which can be used when driving the RoSSAV with CPS/INS and Laser Scanner sensors was developed for measuring the cross-slop. Also, in order to examine the algorithm, the superelevation was measured by Laser Scanner and GPS/INS system during travelling and the result was verified by statistical verification.

• ETRI Journal
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• v.30 no.1
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• pp.59-67
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• 2008

The necessity for the precise time synchronization of measurement data from multiple sensors is widely recognized in the field of global positioning system/inertial navigation system (GPS/INS) integration. Having precise time synchronization is critical for achieving high data fusion performance. The limitations and advantages of various time synchronization scenarios and existing solutions are investigated in this paper. A criterion for evaluating synchronization accuracy requirements is derived on the basis of a comparison of the Kalman filter innovation series and the platform dynamics. An innovative time synchronization solution using a counter and two latching registers is proposed. The proposed solution has been implemented with off-the-shelf components and tested. The resolution and accuracy analysis shows that the proposed solution can achieve a time synchronization accuracy of 0.1 ms if INS can provide a hard-wired timing signal. A synchronization accuracy of 2 ms was achieved when the test system was used to synchronize a low-grade micro-electromechanical inertial measurement unit (IMU), which has only an RS-232 data output interface.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.479-484
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• 2010

In the airborne laser survey with GPS/INS, based on kinematic, the installation and operation of GPS base stations is necessary to allow three-dimensional location coordinates to be obtained quickly and precisely. However, in many cases, GPS base stations operate under difficult conditions. In this paper, we investigate the substitutability of continuously operating reference stations (CORS) for base stations, and we examine the influence of the distance between aircraft GPS and CORS on the Z-value. The results of our study demonstrate that, if the performance of GPS base stations within regulation distance is replaced with that of CORS, sufficient accuracy is guaranteed. Moreover, the performance of CORS beyond regulation distance is fairly good.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.51-64
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• 2009

A location tracking sensor such as GPS, INS, Radar, and optical equipments is used in tracking Maneuvering Targets with a multi-sensor, and such systems are used to track, detect, and control UAV, guided missile, and spaceship. Until now, Most of the studies related to tracking Maneuvering Targets are on fusing multiple Radars, or adding a supplementary sensor to INS and GPS. However, A study is required to change the degree of application in fusions since the system property and error property are different from sensors. In this paper, we perform the error analysis of the sensor properties by adding a ground radar to GPS and INS for improving the tracking performance by multi-sensor fusion, and suggest the tracking algorithm that improves the precision and stability by changing the sensor probability of each sensor according to the error. For evaluation, we extract the altitude values in a simulation for the trajectory of UAV and apply the suggested algorithm to carry out the performance analysis. In this study, we change the weight of the evaluated values according to the degree of error between the navigation information of each sensor to improve the precision of navigation information, and made it possible to have a strong tracking which is not affected by external purposed environmental change and disturbance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.74-80
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• 2006

GPS, which has been opened to the public since the 1980's, uses the C/A code time of arrival to estimate the position, and measures the carrier doppler frequency to estimate the velocity. In development from the 1990's, DGPS has improved position accuracy by eliminating common errors and CDGPS has achieved cm-level position accuracy using carrier phase. In this paper, a modified LSAST ambiguity resolution method for CDGPS is proposed to improve reliability and computational efficiency. Also the test results of cm level relative positioning of a moving vehicle using single frequency GPS receivers are compared to INS position. This research result can be widely used for the development of high precision INS, unmanned autonomous driving, survey and mapping, etc.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.129-134
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• 2003

Mobile Mapping System needs system calibration of multi sensors. System calibration is defined as determination of spatial and rotational offsets between the sensors. Especially, EO parameters of GPS/INS require knowledge of the calibration to camera frame. The calibration parameters must be determined with the highest achievable accuracy in order to get 3D coordinate points in stereo CCD images. This study applies Boresight calibration for the calibration between GPS/INS and camera, and estimates the Performance of the calibration.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.183-195
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• 2004

Photogrammetry is one of the most important sources of GIS application. Nowadays, color photos are used and camera is integrated with GPS/INS sensors. However the photos are still taken from analogue camera and scanned for digital image. For the convenient and accurate image application especially for 3D, airborne digital camera images is essential. In this paper, digital image calibration process with GPS/INS and its accuracy evaluation was presented.