scholarly journals Precise Position Measurement in Hilly and Mountainous Orchard Using Quasi-zenith Satellite System

2021 ◽  
Vol 56 (2) ◽  
pp. 125-127
Author(s):  
Suguru YAMANE
Keyword(s):  
Satellite System ◽  
Position Measurement ◽  
Precise Position

3D calibration for micro-manipulation with precise position measurement

2001 ◽  
Vol 1 (2) ◽  
pp. 117-130 ◽  
Author(s):  
Akiko Kawaji ◽  
Toshio Fukuda ◽  
Fumihito Arai
Keyword(s):  
Position Measurement ◽  
Precise Position

scholarly journals PERFORMANCE ANALYSIS OF DOPPLER AIDED GPS/QZSS PRECISE POSITIONING FOR LAND VEHICLES

2013 ◽  
Vol 20 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Byung-Hyun Lee ◽  
Gyu-In Jee
Keyword(s):  
Urban Area ◽  
Elevation Angle ◽  
Satellite System ◽  
Transport Systems ◽  
Doppler Measurement ◽  
Precise Positioning ◽  
Multipath Error ◽  
Precise Position ◽  
Land Vehicles ◽  
Positioning Errors

ABSTRACT For ITS (Intelligent Transport Systems), especially for land vehicles, precise position is the prime information. GNSS is the most popular navigation system. Generally, ITS demands lane distinguishable positioning accuracy. However urban area is most environments of land vehicles and the signal blocks of satellite with low elevation angle, multipath error and etc. make unreliable positioning results. Especially, lack of number of visible satellites (fewer than 4 satellites) cannot provide positioning results. QZSS (Quasi-Zenith Satellite System) which operated by Japan has high interoperability. In addition, its elevation angle is very high in long time in Korea. It means QZSS signal can be received in urban area and it can be great advantage for land vehicles. The most positioning errors are occurred by multipath, cycle slip, and etc. For example, multipath error is unexpected momentary error. In order to reduce position error, smoothing technique in position domain is needed. In this paper, precise positioning for land vehicles was evaluated. First, by using QZSS, probability of navigation solution was enhanced. Second, the reliability is improved by smoothing positioning result using Doppler measurement. The analysis was performed by trajectory analysis using precise map data.

A Precise Position Measurement System of Roll-to-Roll Printing Using Burst Alignment Patterns

2018 ◽  
Author(s):  
Taehyeong Kim ◽  
Dongho Oh ◽  
Youngjin Kim ◽  
Jihyeon Kim ◽  
Byeongcheol Lee
Keyword(s):  
Measurement System ◽  
High Speed ◽  
Printed Electronics ◽  
High Volume ◽  
Measurement Range ◽  
Generation Process ◽  
Position Measurement ◽  
Process Technology ◽  
Precise Position ◽  
Roll To Roll

Printed electronics is a next-generation process technology that is suitable for high speed and high volume production and can make electronic devices and circuits on flexible materials. To commercialize printed electronics, it is necessary to improve the alignment precision of printing. In order to improve the alignment precision of the roll-to-roll process, accurate measurement of the web position is required. Therefore, in the previous research of this paper, we proposed a measurement system of the moving direction and the lateral movement using an encoder. However, in the previous study, the direction of error control had to be set according to the measurement position of the encoder, and the measurement range was so narrow. In this paper, we propose a measurement system that can detect the direction of error and increase the effective measurement range using the burst alignment pattern that generates the burst signal. Applying it to roll-to-roll printing position measurement systems, measurements can be performed with greatly improved efficiency and measurement range.

A precise position measurement system of roll-to-roll printing using burst alignment patterns

2019 ◽  
Vol 26 (1) ◽  
pp. 231-238
Author(s):  
Taehyeong Kim ◽  
Youngjin Kim ◽  
Jihyeon Kim ◽  
Byeongcheol Lee ◽  
Jimin Park ◽  
...  
Keyword(s):  
Measurement System ◽  
Position Measurement ◽  
Precise Position ◽  
Roll To Roll

scholarly journals Semantic VPS for Smartphone Localization in Challenging Urban Environments

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6137
Author(s):  
Max Jwo Lem Lee ◽  
Li-Ta Hsu ◽  
Hoi-Fung Ng
Keyword(s):  
Smart Cities ◽  
Satellite System ◽  
Urban Environments ◽  
Position Estimation ◽  
Information Modeling ◽  
Position Information ◽  
Precise Position ◽  
Segmented Images ◽  
Building Information ◽  
Global Navigation Satellite

Accurate smartphone-based outdoor localization systems in deep urban canyons are increasingly needed for various IoT applications. As smart cities have developed, building information modeling (BIM) has become widely available. This article, for the first time, presents a semantic Visual Positioning System (VPS) for accurate and robust position estimation in urban canyons where the global navigation satellite system (GNSS) tends to fail. In the offline stage, a material segmented BIM is used to generate segmented images. In the online stage, an image is taken with a smartphone camera that provides textual information about the surrounding environment. The approach utilizes computer vision algorithms to segment between the different types of material class identified in the smartphone image. A semantic VPS method is then used to match the segmented generated images with the segmented smartphone image. Each generated image contains position information in terms of latitude, longitude, altitude, yaw, pitch, and roll. The candidate with the maximum likelihood is regarded as the precise position of the user. The positioning result achieved an accuracy of 2.0 m among high-rise buildings on a street, 5.5 m in a dense foliage environment, and 15.7 m in an alleyway. This represents an improvement in positioning of 45% compared to the current state-of-the-art method. The estimation of yaw achieved accuracy of 2.3°, an eight-fold improvement compared to the smartphone IMU.

scholarly journals Tight Fusion of a Monocular Camera, MEMS-IMU, and Single-Frequency Multi-GNSS RTK for Precise Navigation in GNSS-Challenged Environments

2019 ◽  
Vol 11 (6) ◽  
pp. 610 ◽  
Author(s):  
Tuan Li ◽  
Hongping Zhang ◽  
Zhouzheng Gao ◽  
Xiaoji Niu ◽  
Naser El-sheimy
Keyword(s):  
Kalman Filter ◽  
Low Cost ◽  
Measurement Model ◽  
Satellite System ◽  
Single Frequency ◽  
Precise Position ◽  
Monocular Camera ◽  
Tightly Coupled ◽  
Self Driving Cars ◽  
Mems Imu

Precise position, velocity, and attitude is essential for self-driving cars and unmanned aerial vehicles (UAVs). The integration of global navigation satellite system (GNSS) real-time kinematics (RTK) and inertial measurement units (IMUs) is able to provide high-accuracy navigation solutions in open-sky conditions, but the accuracy will be degraded severely in GNSS-challenged environments, especially integrated with the low-cost microelectromechanical system (MEMS) IMUs. In order to navigate in GNSS-denied environments, the visual–inertial system has been widely adopted due to its complementary characteristics, but it suffers from error accumulation. In this contribution, we tightly integrate the raw measurements from the single-frequency multi-GNSS RTK, MEMS-IMU, and monocular camera through the extended Kalman filter (EKF) to enhance the navigation performance in terms of accuracy, continuity, and availability. The visual measurement model from the well-known multistate constraint Kalman filter (MSCKF) is combined with the double-differenced GNSS measurement model to update the integration filter. A field vehicular experiment was carried out in GNSS-challenged environments to evaluate the performance of the proposed algorithm. Results indicate that both multi-GNSS and vision contribute significantly to the centimeter-level positioning availability in GNSS-challenged environments. Meanwhile, the velocity and attitude accuracy can be greatly improved by using the tightly-coupled multi-GNSS RTK/INS/Vision integration, especially for the yaw angle.

Research on Precision Construction Measurement of Curved Surface Steel Structure Project

2011 ◽  
Vol 94-96 ◽  
pp. 1363-1368
Author(s):  
Deng Jie Wang ◽  
Guang Yue Wang
Keyword(s):  
Linear Equation ◽  
Steel Structure ◽  
Curved Surface ◽  
Measurement Technology ◽  
Construction Control ◽  
Construction Process ◽  
Position Measurement ◽  
Precise Position ◽  
Elevation Measurement

The positioning measurement of spatial curved surface steel structure project is a key link in construction process. How to measure position fast and precisely is an important problem concerned by steel structure project field. Taking actual project as an example, this article studied precision construction measurement technology in curved surface steel structure project, put forward resemble-leveling method elevation measurement, and naturalization lofting method which is based on spatial linear equation. This article has important guiding significance to precise position measurement of curved surface steel structure project and to construction control.

scholarly journals A 24 GHz Waveguide based Radar System using an Advanced Algorithm for I/Q Offset Cancelation

2017 ◽  
Vol 15 ◽  
pp. 249-258 ◽  
Author(s):  
Christoph Will ◽  
Sarah Linz ◽  
Sebastian Mann ◽  
Fabian Lurz ◽  
Stefan Lindner ◽  
...  
Keyword(s):  
Phase Shifter ◽  
Industrial Applications ◽  
Radar System ◽  
Guided Wave ◽  
Position Measurement ◽  
Intelligent Algorithm ◽  
Precise Position ◽  
Analog To Digital ◽  
Baseband Signal ◽  
Scale Range

Abstract. Precise position measurement with micrometer accuracy plays an important role in modern industrial applications. Herewith, a guided wave Six-Port interferometric radar system is presented. Due to limited matching and discontinuities in the radio frequency part of the system, the designers have to deal with DC offsets. The offset voltages in the baseband lead to worse relative modulation dynamics relating to the full scale range of the analog-to-digital converters and thus, considerably degrade the system performance. While common cancelation techniques try to estimate and extinguish the DC offsets directly, the proposed radar system is satisfied with equalizing both DC offsets for each of the two differential baseband signal pairs. Since the complex representation of the baseband signals is utilized for a subsequent arctangent demodulation, the proposed offset equalization implicates a centering of the in-phase and quadrature (I/Q) components of the received signal, which is sufficient to simplify the demodulation and improve the phase accuracy. Therefore, a standard Six-Port radar system is extended and a variable phase shifter plus variable attenuators are inserted at different positions. An intelligent algorithm adjusts these configurable components to achieve optimal I/Q offset cancelation.

scholarly journals Multifunctional Ground Control Points with a Wireless Network for Communication with a UAV

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2852 ◽  
Author(s):  
Xiongzhe Han ◽  
J. Thomasson ◽  
Yang Xiang ◽  
Hussein Gharakhani ◽  
Pappu Yadav ◽  
...  
Keyword(s):  
Wireless Network ◽  
Strong Relationship ◽  
Ground Control ◽  
Average Height ◽  
Control Points ◽  
Radiometric Calibration ◽  
Position Measurement ◽  
Precise Position ◽  
Ground Control Points ◽  
Average Reflectance

Ground control points (GCPs) are commonly used for georeferencing in remote sensing. Precise position measurement of the GCPs typically requires careful ground surveying, which is time-consuming and labor-intensive and thus excessively costly if it needs to be repeated multiple times in a season. A system of multifunctional GCPs and a wireless network for communication with an unmanned aerial vehicle (UAV) was developed to improve the speed of GCP setup and provide GCP data collection in real-time during the flight. While testing the system, a single-board computer on a fixed-wing UAV used in the study successfully recorded position data from all the GCPs during the flight. The multifunctional GCPs were also tested for use as references for calibration of reflectance and height for field objects like crops. The test of radiometric calibration resulted in an average reflectance error of 2.0% and a strong relationship (R2 = 0.99) between UAV-based estimates and ground reflectance. Furthermore, the average height difference between UAV-based height estimates and ground measurements was within 10 cm.

scholarly journals Validation of the Accuracy and Convergence Time of Real Time Kinematic Results Using a Single Galileo Navigation System

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2412 ◽  
Author(s):  
Zbigniew Siejka
Keyword(s):  
Real Time ◽  
Navigation System ◽  
Satellite System ◽  
Convergence Time ◽  
Navigation Systems ◽  
Precise Position ◽  
Positioning Systems ◽  
Real Time Kinematic ◽  
Global Navigation

For the last two decades, the American GPS and Russian GLONASS were the basic systems used in global positioning and navigation. In recent years, there has been significant progress in the development of positioning systems. New regional systems have been created, i.e., the Japanese Quasi-Zenith Satellite System (QZSS) and Indian Regional Navigational Satellite System (IRNSS). A plan to build its own regional navigation system named Korean Positioning System (KPS) was announced South Korea on 5 February 2018. Currently, two new global navigation systems are under development: the European Galileo and the Chinese BeiDou. The full operability of both systems by 2020 is planned. The paper deals with a possibility of determination of the user’s position from individual and independent global navigation satellite system (GNSS). The article is a broader concept aimed at independent determination of precise position from individual GPS, GLONASS, BeiDou and Galileo systems. It presents real time positioning results (Real Time Kinematic-RTK) using signals from Galileo satellites only. During the test, 14 Galileo satellites were used and the number of simultaneously observed Galileo satellites varied from five to seven. Real-time measurements were only possible in certain 24-h observation windows. However, their number was completed within 6 days at the end of 2017 and beginning of 2018, so there was possible to infer about the current availability, continuity, convergence time and accuracy of the RTK measurements. In addition, the systematic errors were demonstrated for the Galileo system.

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