• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.3
• /
• pp.242-247
• /
• 2008

As an absolute positioning system, iGS is designed based on ultrasonic signals whose speed can be formulated clearly in terms of time and room temperature, which is utilized for a mobile robot localization. The iGS is composed of an RFID receiver and an ultra-sonic transmitter, where an RFID is designated to synchronize the transmitter and receiver of the ultrasonic signal. The traveling time of the ultrasonic signal has been used to calculate the distance between the iGS system and a beacon which is located at a pre-determined location. This paper suggests an effective operation method of iGS to estimate position of the mobile robot working in unstructured environment. To expand recognition range and to improve accuracy of the system, two strategies are proposed: utilization of beacons belonging to neighboring blocks and removal of the environment-reflected ultrasonic signals. As the results, the ubiquitous localization system based on iGS as a pseudo-satellite system has been developed successfully with a low cost, a high update rate, and relatively high precision.

• Annual Conference of KIPS
• /
• 2016.04a
• /
• pp.88-91
• /
• 2016

최근 스마트 기기의 활용 요구 증가로 인한 실내 위치 인식 시스템 수요가 급증함에 따라, BLE(Bluetooth Low Energy) 비콘을 이용한 실내 측위 시스템이 각광받고 있다. 본 논문은 BLE 비콘 기반에 중심을 두고 RSSI 신호를 이용하여 거시적인 삼변 측량 기법을 이용하여 산출한다. 그 결과값을 근사치 위치에만 Fingerprinting을 적용하여 위치 측위 기본 연산량을 줄임과 동시에 에너지 효율을 증대시킨다. 또한 선정된 Fingerprinting Cell 주위의 노드만을 이용하여 사용자의 단말 위치의 정밀성을 보장하는 정밀 삼변 측량 연산을 수행하여 에너지 효율을 고려한 BLE 핑거프린팅 기반의 정밀 실내 측위 알고리즘을 제안한다.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.1
• /
• pp.71-76
• /
• 2017

Recently, there are various researches using inaudible high frequencies like as wireless communication based smart devices, data transmission algorithm, indoor positioning trace technologies. However, when they use high frequencies of inaudible range, they have a problem that the accuracy of data transmission with high frequencies was low because of interference from ambient noise in our real life. To solve this problem, in this paper, we proposed an application based on smart phone and server system for collection of ambient noise and detection of robust high frequency range. The server system could detect the robust high frequency range from statistical analysis of collected noise and the robust high frequency could avoid interference from ambient noise. We tested the proposed application's ability to gather noise and high frequencies for a certain period of time to evaluate performance. According to the testing results, we confirmed that the proposed application and server system could detect a robust high-frequency range via noise analysis in real life. Therefore, the proposed application and server could be a useful technology for future research on inaudible high frequencies.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.9
• /
• pp.891-897
• /
• 2006

The coverage of the NDGPS is nationwide currently and by 2007 more than 2 NDGPS signal will be available in most of Korean peninsula both coastal area and inland. The role of NDGPS beacon is transmitting pseudorange corrections however if range or pseudorange can be measured from NDGPS beacon signal, it might be possible to construct an independent regional navigation system: The range from NDGPS beacon signal can be used as additional measurements to remove GPS shadow area and to improve accuracy and reliability of GPS. Furthermore, by adding Loran-C, a regional radio navigation system without GPS can be possible. In this paper, a feasibility study on the regional positioning system using NDGPS and LORAN-C are given. The results show that the NDGPS and LORAN-C can be used as a ground based regional navigation system if requirements such as synchronization of NDGPS network, dual coverage of NDGPS, navigation algorithm for both NDGPS and LORAN-C measurements and an efficient ASF compensation method are met.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.9
• /
• pp.883-890
• /
• 2006

Nowadays, CPS is used widely, especially in cases which need more precise position information, such as car navigation systems and even in the mobile robot for position measuring in the outdoor environment. RTK (Real-Time Kinematics) and DGPS (Differential Global Positioning System) have more precise accuracy than the general-purposed GPS. However can't easily use them because of high prices and large size of equipments. In order fur the mobile robot to obtain precise position information it is important that CPS receiver has portability and low price. In this study, we introduce a new GPS data acquisition system that offers the precise position data using the DGPS mechanism and satisfying low cost and portability. In addition to this, we propose an improved data compensation algorithm that offers more accurate position information to the outdoor mobile robot by compensating the error rate of CPS data measured from the three points with geometrical rotation and distance formula. Proposed method is verified by comparing with the precise real position data obtained by RTK. Proposed method has more than 70% performance enhancement.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.3
• /
• pp.188-192
• /
• 2012

In this study, a carbon nanotube (CNT) flexible strain sensor was fabricated with CNT based epoxy and rubber composites for tactile sensing. The flexible strain sensor can be fabricated as a long fibrous sensor and it also may be able to measure large deformation and contact information on a structure. The long and flexible sensor can be considered to be a continuous sensor like a dendrite of a neuron in the human body and we named the sensor as a biomimetic artificial neuron. For the application of the neuron in biomimetic engineering, an ANMS (Artificial Neuron Matrix System) was developed by means of the array of the neurons with a signal processing system. Moreover, a strain positioning algorithm was also developed to find localized tactile information of the ANMS with Labview for the application of an artificial e-skin.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.2
• /
• pp.191-197
• /
• 2002

Recently, with the eye-opening progress in the related field of computer, the development of high resolution digital camera enables more precise positioning in digital photogrammetry, and a lot of interest has been concentrated on its application. In this study, the algorithm and system which enable the measurement of 3D point more easily was developed by image pointing method using digital image, when the digital map of the Cultural Properties of Architectures in Modern Ages is drawn by photogrammetry. As a result, we can reduce the limitation of surveying control point, exposure condition, and construct the digital map and 3D model of architecture more efficiently.

• International Journal of Ocean System Engineering
• /
• v.3 no.2
• /
• pp.50-60
• /
• 2013

This paper presents a novel approach to the design of an adaptive fuzzy sliding mode controller for depth control of an autonomous underwater vehicle (AUV). So far, AUV's dynamics are highly nonlinear and the hydrodynamic coefficients of the vehicles are difficult to estimate, because of the variations of these coefficients with different operating conditions. These kinds of difficulties cause modeling inaccuracies of AUV's dynamics. Hence, we propose an adaptive fuzzy sliding mode control with novel fuzzy adaptation technique for regulating vertical positioning in presence of parametric uncertainty and disturbances. In this approach, two fuzzy approximator are employed in such a way that slope of the linear sliding surface is updated by first fuzzy approximator, to shape tracking error dynamics in the sliding regime, while second fuzzy approximator change the supports of the output fuzzy membership function in the defuzzification inference module of fuzzy sliding mode control (FSMC) algorithm. Simulation results shows that, the reaching time and tracking error in the approaching phase can be significantly reduced with chattering problem can also be eliminated. The effectiveness of proposed control strategy and its advantages are indicated in comparison with conventional sliding mode control FSMC technique.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.2
• /
• pp.169-176
• /
• 2012

GPS(Global Positioning System) is widely used for the position estimation of an aerial vehicle. However, GPS may not be available due to hostile jamming or strategic reasons. A vision-based position estimation method can be effective if GPS does not work properly. In mountainous areas without any man-made landmark, a horizon is a good feature for estimating the position of an aerial vehicle. In this paper, we present a new method to estimate the position of the aerial vehicle equipped with a forward-looking infrared camera. It is assumed that INS(Inertial Navigation System) provides the attitudes of an aerial vehicle and a camera. The horizon extracted from an infrared image is compared with horizon models generated from DEM(Digital Elevation Map). Because of a narrow field of view of the camera, two images with a different camera view are utilized to estimate a position. The algorithm is tested using real infrared images acquired on the ground. The experimental results show that the method can be used for estimating the position of an aerial vehicle.

• International Journal of Automotive Technology
• /
• v.8 no.5
• /
• pp.583-591
• /
• 2007

This paper describes the development of the $H_{\infty}$ lateral control system for an autonomous ground vehicle operating a limited area using the RTK-DGPS(Real Time Kinematic-Differential Global Positioning System). Before engaging in autonomous driving, map data are acquired by the RTK-DGPS and used to construct a reference trajectory. The navigation system contains the map data and computes the reference yaw angle of the vehicle using two consecutive position values. The yaw angle of the vehicle is controlled by the $H_{\infty}$ controller. A prototype of the autonomous vehicle by the navigation method has been developed, and the performance of the vehicle has been evaluated by experiment. The experimental results show that the $H_{\infty}$ controller and the RTK-DGPS based navigation system can sufficiently track the map at low speed. We expect that this navigation system can be made more accurate by incorporating additional sensors.