Earticle

This study proposes a vehicle positioning system that integrates RTK-based Global Navigation Satellite System (GNSS), an Inertial Measurement Unit (IMU), and wheel-tick data obtained from the vehicle’s On-Board Diagnostics (OBD) to overcome the frequent GNSS signal outages and multipath effects that occur in urban, underground, and tunnel environments. To ensure stable positioning even under unstable RTK signal conditions, an Extended Kalman Filter (EKF) was applied. Experimental results show that the proposed system improves positioning accuracy by approximately 5 meters in open-sky environments using RTK. Under Dead Reckoning (DR) conditions, integrating OBD-based wheel-tick data with the IMU reduced the position error by up to 30 meters compared to using the IMU alone. Furthermore, in tunnel-driving experiments, the system maintained a position error within 3.5 meters even when GNSS signals were completely lost. The proposed method demonstrates practical applicability in various domains requiring high-precision positioning, such as autonomous driving, high-definition map construction, and real-time vehicle monitoring.

The need for precise location data is growing across numerous markets, and so is the number of affordable high-precision GPS receivers. In this paper, we validated the performance of RTAP2U, a low-cost high-precision RTK receiver that was recently released. Two positioning modes were tested: static and driving. The static test conducted Zero-Baseline Single-RTK and Network-RTK survey for 57 hours and 51 hours, respectively. For the driving test, Network-RTK survey was conducted using VRS services provided by NGII based on Trimble PIVOT and Geo++ GNSMART. The static test showed about 1 cm horizontal and vertical accuracies, which is very stable considering the test duration longer than 50 hours. The integer ambiguity FIX rate marked a solid 100%. The driving test result also reached a 100% FIX rate. Horizontal and vertical accuracies were better than 2 cm and 3 cm, respectively. Researchers can refer to this paper when considering affordable high-precision GPS receivers as an option.

UWB (Ultra Wide Band) refers to a system with a bandwidth of over 500 MHz or a bandwidth of 20% of the center frequency. It is robust against channel fading and has a wide signal bandwidth. Using the IR-UWB based ranging system, it is possible to obtain decimeter-level ranging accuracy. Furthermore, IR-UWB system enables acquisition over glass or cement with high resolution. In recent years, IR-UWB-based ranging chipsets have become cheap and popular, and it has become possible to implement positioning systems of several tens of centimeters. The system can be configured as one-way ranging (OWR) positioning system for fast ranging and TWR (two-way ranging) positioning system for cheap and robust ranging. On the other hand, the ranging based positioning system has a limitation on the number of terminals for localization because it takes time to perform a communication procedure to perform ranging. To overcome this problem, code multiplexing and channel multiplexing are performed. However, errors occur in measurement due to interference between channels and code, multipath, and so on. The measurement filtering is used to reduce the measurement error, but more fundamentally, techniques for removing these measurements should be studied. First, the TWR based positioning was analyzed from a stochastic point of view and the effects of outlier measurements were summarized. The positioning algorithm for analytically identifying and removing single outlier is summarized and extended to three dimensions. Through the simulation, we have verified the algorithm to detect and remove single outliers.

Recently, the interests of the precise localization are rapidly increasing, which are linked to IoT(Internet of Things) sensors. The precise localization in indoor environment can be utilized in navigation, security, anti-collision, and various location based services etc. However, conventional positioning sensors, such as PIR, ultrasonic, microwave etc. are vulnerable to weather or insensitive to direction of subject movement or low precision performance. In this paper we implement a UWB-IR localization system for long distance and high-precision localization, which is not affected by temperature, light and weather. The proposed system was divided and designed by H/W, Antenna, S/W parts, each of which was designed based on an accurate analysis and simulation. As a result, we can implemented and verified UWB IR system with precise localization performance.

최근 실내 위치 인식을 위하여 IEEE 802.15.4a에 기반한 거리측정 및 이 값들을 이용한 다양한 위치 인식 기법이 제안되고 있다. 본 논문에서는 실내에서 간단한 초음파 모듈과 적은 수의 IEEE 802.15.4a 노드를 이용하여 고정밀 위치정보를 제공하는 기법을 제시한다. 제안된 기법이 기존의 삼변측량기법에 비해서 실내환경에 존재하는 다양한 전파 방해에 덜 민감하여 보다 높은 정밀도를 제공한다는 것을 실제적인 구현과 실험을 통하여 검증한다. 또한, 제안된 기법은 삼변측량을 이용할 때보다 상대적으로 적은 수의 노드를 이용하기 때문에 경제적인 측면에서도 이점이 존재한다.

최근 실내 위치 인식을 위하여 IEEE 802.15.4a에 기반한 거리측정 및 이 값들을 이용한 다양한 위치 인식 기법이 제안되고 있다. 본 논문에서는 실내에서 간단한 초음파 모듈과 적은 수의 IEEE 802.15.4a 노드를 이용하여 고정밀 위치정보를 제공하는 기법을 제시한다. 제안된 기법이 기존의 삼변측량기법에 비해서 실내환경에 존재하는 다양한 전파 방해에 덜 민감하여 보다 높은 정밀도를 제공한다는 것을 실제적인 구현과 실험을 통하여 검증한다. 또한, 제안된 기법은 삼변측량을 이용할 때보다 상대적으로 적은 수의 노드를 이용하기 때문에 경제적인 측면에서도 이점이 존재한다.

일반적으로 머신비전을 이용한 위치 추정 정밀도는 카메라의 화소 수에 비례한다. 머신비전 카메라의 경우 화소가 많을수록 카메라 가격이 크게 증가하므로 화소 수만을 늘려서 정밀도를 높이는 하드웨어적 방법은 활용이 제한적이다. 이런 문제를 해결하기 위해서 적은 화소 수로 높은 위치 추정 정밀도를 얻을 수 있는 다양한 소프트웨어 알고리즘에 대한 연구가 진행되어 왔다. 본 논문에서는 위치 추정 정밀도를 높이기 위한 서브 픽셀 위치 추정 알고리즘을 구현하고 이를 반도체 칩 검사용 고정밀 스테이지에 적용하였다.