• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.23 no.1
• /
• pp.167-181
• /
• 2024

Utilization of a driving simulator in the development of autonomous driving technology allows us to perform various tests effectively in criticial environments, thereby reducing the development cost and efforts. However, there exists a serious drawback that the driving simulator has a big difference from the real environment, so a problem occurs when the autonomous driving algorithm developed using the driving simulator is applied directly to the real vehicle system. This is defined as so-called Sim2Real problem and can be classified into scenarios, sensor modeling, and vehicle dynamics. This Paper presensts on a method to solve the Sim2Real problem in autonomous driving simulator focusing on IMU sensor. In order to reduce the difference between emulated virtual IMU sensor real IMU sensor, IMU sensor emulation techniques through precision error modeling of IMU sensor are introduced. The error model of IMU sensors takes into account bias, scale factor, misalignmnet, and random walk by IMU sensor grades.

• Journal of Navigation and Port Research
• /
• v.37 no.3
• /
• pp.309-313
• /
• 2013

This paper is about a complex sensor system of an automatic guided vehicle(AGV) for loading and unloading payloads. For the AGV to approach to the target rack for loading and unloading the payload, a way to identify the position and orientation was studied. To identify the position and orientation of the AGV accurately, a complex sensor system composed of RFID, IMU, and limit sensors was developed, and the performance of each sensor was undertaken. A model AGV was constructed, and the good performance of the developed complex sensor system was verified through performance experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.10
• /
• pp.53-59
• /
• 2004

A calibration technique for a redundant IMU with low-grade inertial sensors is proposed. In order to calibrate the redundant IMU that can detect and isolate a faulty sensor, the fundamental coordinate frames in the IMU are defined and the IMU error is modeled based on the frames. Equations to estimate the error coefficients of the redundant IMU are formulated, and a test sequence using the 2-axis rate table is also presented. Finally, a redundant IMU with cone configuration is implemented using the low-grade inertial sensors and the performance of the proposed technique is verified by some experiments.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.07a
• /
• pp.491-492
• /
• 2022

본 연구에서는 실내 공간 정보 획득을 위한 IMU/INS 항법장치에 관한 연구를 위한 선행연구를 수행 하였다. 최근의 GPS를 이용한 내비게이션의 경우 보통 5~10m의 위치 오차가 일어나지만 아파트나 대형시설과 같이 실내, 터널, 공장지대 및 산악 지대등 상당한 지역은 GPS의 사각지대 또는 오차 범위를 벗어난 지역으로 존재하고 있다. 따라서 GPS는 실내에서는 사용이 불가능 하므로 다른 방안이 제시되어야 한다. 현재 고속 연산을 위한 고성능 마이크로프로세서의 발전은 센서 분야에 적용되어 저 전력, 고 정밀, 소형의 IMU/INS, ARS/AHRS 센서가 개발되고 있다. 본 연구에서는 IMU(inertial measurement unit)와 INS(Inertial Navigation System)을 이용하여 IMU자체의 자이로 센서와 가속도 센서를 이용한 GPS의 위성신호가 감지되지 않는 지형에서도 속도의 적분값과 회전방향을 이용하여 위치인식이 가능하도록 정보를 계산하여 자기의 위치를 추적하는 방안을 연구하였다.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.2
• /
• pp.186-192
• /
• 2014

This study presents the remote control of a board robot using an IMU sensor based on Bluetooth communication. The board robot is a kind of riding robot controlled throng wireless communication by a user. The user wears the proposed IMU sensor controller, and changes a direction of the robot by the angles of IMU sensor. Bluetooth is used for wireless communication between the board robot and its user. The IMU sensor in the remote controller is used for recognition of a number of actions, which are measured as analog signals. The user actions have five commands ('1'right '2'neutrality '3'left '4'operation '5'stop), which are transmitted from the user to the board robot through Bluetooth communication. Experimental results show that proposed IMU interface can effectively control the board robot.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.28 no.1
• /
• pp.65-72
• /
• 2010

In this study, the performances of a medium grade IMU which is aimed for Mobile Mapping System and a low grade IMU for pedestrian navigation are analyzed through simulations under GPS signal blockage. In addition, an analysis on the accuracy improvement of barometer, electronic compass, or multi-sensor(combination of barometer and electronic compass) to correct medium grade or low grade IMU errors in the situation of GPS signal blockage is performed. With the medium grade IMU, the three dimensional positioning error from INS exceeds the demanded accuracy of 5m when the block time is over 30 seconds. When we correct IMU with barometer, compass, or multi-sensor, however, the demanded accuracy is maintained up to 60 seconds. In addition, barometer is more effective than the electronic compass when they are combined. In case of low grade IMU like MEMS IMU, the three dimensional positioning error from INS exceeds the demanded accuracy of 20m when the block time is over 15 seconds. When we correct INS with barometer, compass, or multi-sensor, however, the demanded accuracy is maintained up to 15 seconds in simulation results. On the contrary to medium grade IMU, electronic compass is more effective than the barometer in case of low velocity such as pedestrian navigation. It is expected that the analysis suggested a method to decrease position or attitude error using aided sensor integration when MMS or pedestrian navigation is operated under 1he environment of GPS signal blockage.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.1
• /
• pp.65-72
• /
• 2012

With the development of MEMS, small and low-priced sensors integrating IMU and GPS have produced and exploited for diverse field. In this research, we have judged that MEMS-based IMU/GPS sensor is suitable for light-weighted mobile mapping system and carried out experiments to analyze the characteristics of MTi-G, which was developed from XSens company. From a sensor which fixed to dashboard, coordinates results with no post-processing were achieved for test area. On the whole, the results show satisfactory performances but some errors also were discovered from parts of the road due to sensor properties, XKF characteristics and GPS reception environment. We could confirm the potential of light-weighted mobile mapping system. Experiments considering various GPS reception environments and road condition and more detailed level of accuracy analysis will be performed for further research.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.18-20
• /
• 2021

In order to prevent collision accidents of ships, which has been increasing recently, research on artificial intelligence-based autonomously operated ships (Maritime Autonomous Surface Ship, MASS) is underway. However, most of the studies related to autonomous ships mainly target medium-to-large ships due to the size and cost of the autonomous navigation system, and the sensors used here have a problem in that it is difficult to mount them on small ships. Therefore, this paper provides a path tracking system equipped with GPS and IMU sensors for autonomous operation of small ships. GPS and IMU sensors are utilized to determine the exact position of the vessel, which allows the proposed system to manually control the small vessel model to create a path and then when the small vessel travels the same path. Use the Pure Pursuit algorithm to follow the path. As a result, In this research, it is expected that a lightweight and low-cost sensor can be used to develop an autonomous operation system for small ships at low cost.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.2
• /
• pp.249-260
• /
• 2009

The georeferencing accuracy of the sensory data acquired by an aerial monitoring system heavily depends on the performance of the GPS/IMU mounted on the system. The employment of a high performance but expensive GPS/IMU unit causes to increase the developmental cost of the overall system. In this study, we simulate the images and GPS/IMU data acquired by an UAV-based aerial monitoring system using an inexpensive integrated GPS/IMU of a MEMS type, and perform the image georeferencing by applying the aerial triangulation to the simulated sensory data without any GCP. The image georeferencing results are then analyzed to assess the accuracy of the estimated exterior orientation parameters of the images and ground points coordinates. The analysis indicates that the RMSEs of the exterior orientation parameters and ground point coordinates is significantly decreased by about 90% in comparison with those resulted from the direct georeferencing without the aerial triangulation. From this study, we confirmed the high possibility to develop a low-cost real-time aerial monitoring system.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.1
• /
• pp.1-9
• /
• 2007

3D data are in great demand for pedestrian navigation recently. For pedestrian navigation, we needs to reconstruct 3D model in detail from people's eye. In order to present spatial features in detail for pedestrian navigation, it is indispensable to develop 3D model not only in outdoor environment but also in indoor environment such as underground shopping complex. However, it is very difficult to acquire 3D data efficiently by mobile mapping without GPS. In this research, 3D shape was acquired by Laser scanner, and texture by CCD(Charge Coupled Device) sensor. Continuous changes position and attitude of sensors were measured by IMU(Inertial Measurement Unit). Moreover, IMU was corrected by relative orientation of CCD images without GPS(Global Positioning System). In conclusion, Reliable, quick, and handy method for acquiring 3D data for indoor environment is proposed by a combination of a digital camera and a laser scanner with IMU.