Analysis and Simulation of an Autonomous Integrity Monitoring Algorithm for Dual-Mode Navigation Receiver

2013 ◽  
Vol 765-767 ◽  
pp. 2097-2100
Author(s):  
Jun Sun ◽  
Yong Gang Yang
Keyword(s):  
Fault Detection ◽  
Single Mode ◽  
Single System ◽  
Dual Mode ◽  
Integrity Monitoring ◽  
Detection Rates ◽  
Monitoring Algorithm

A dual-mode receiver combination of GPS and Compass (BD) is introduced on the assumption when only one of the satellites had a failure, how to implement a weighting RAIM monitoring. And the GPS and BD in single mode and the GPS/BD dual-mode were simulated to produce the Fault Detection Rates and RAIM integrity availability. It is demonstrated that the dual-mode RAIM algorithm is superior to any kind of single-system RAIM algorithms.

scholarly journals Performance evaluation of GPS / BDS combined single-point positioning based on RTKLIB

2020 ◽  
Vol 165 ◽  
pp. 03009
Author(s):  
Li Yan-yi ◽  
Huang Jin ◽  
Tang Ming-xiu
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Single Point ◽  
Least Square Method ◽  
Least Square ◽  
Filter Method ◽  
Single System ◽  
Positioning Error ◽  
Dual Mode ◽  
Kalman Filter Method

In order to evaluate the performance of GPS / BDS, RTKLIB, an open-source software of GNSS, is used in this paper. In this paper, the least square method, the weighted least square method and the extended Kalman filter method are respectively applied to BDS / GPS single system for data solution. Then, the BDS system and GPS system are used for fusion positioning and the positioning results of the two systems are compared with that of the single system. Through the comparison of experiments, on the premise of using the extended Kalman filter method for positioning, when the GPS signal is not good, BDS data is introduced for dual-mode positioning, the positioning error in e direction is reduced by 36.97%, the positioning error in U direction is reduced by 22.95%, and the spatial positioning error is reduced by 16.01%, which further reflects the advantages of dual-mode positioning in improving a system robustness and reducing the error.

Unstable Vibrations of a Wind Turbine Tower With Two Blades

2012 ◽  
Author(s):  
Takashi Ikeda ◽  
Yuji Harata ◽  
Yukio Ishida
Keyword(s):  
Wind Turbine ◽  
Equations Of Motion ◽  
Single Mode ◽  
Single Frequency ◽  
Dual Mode ◽  
Response Curves ◽  
Moments Of Inertia ◽  
System Parameters ◽  
Wind Turbine Tower ◽  
The Asymmetry

Unstable vibrations of a two-blade wind turbine tower are theoretically investigated. The theoretical model is a five-degree-of-freedom (5DOF) system, however, the equations of motion are derived separately for 3DOF subsystem (I) and 2DOF subsystem (II). Parametric excitation due to the asymmetry of the moments of inertia of the blade rotor is included only in subsystem (I). Frequency equations are derived and natural frequency diagrams are calculated to clearly demonstrate both the rotational speeds where unstable regions appear and which type of unstable vibrations may occur. It is found that at most, five unstable regions may appear depending on the values of the system parameters in subsystem (I). Two types of unstable vibrations may occur; single mode including a single frequency and dual mode including two frequencies. The influences of the asymmetry of moments of inertia, tower rigidity, and installation position of the blade rotor on the response of the system are also theoretically investigated. Van der Pol’s method is applied to determine the expressions for the response curves. The influences of the blade rotor unbalances on the translational, inclinational and torsional vibrations of the tower are shown. It is found that the amplitudes of the response curves corresponding to single and dual mode are infinite and finite at their boundaries, respectively. The validity of the theoretical analysis is confirmed by numerical simulations.

Energy, exergy and economic assessments of the dual-mode evaporative cooler for various international climate zones

2021 ◽  
pp. 014362442110449
Author(s):  
Sarvesh Kashyap ◽  
Jahar Sarkar ◽  
Amitesh Kumar
Keyword(s):  
Operating Cost ◽  
Cost Savings ◽  
Single Mode ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Dual Mode ◽  
Climate Zones ◽  
Operating Modes ◽  
International Climate ◽  
Evaporative Cooler

The conventional desert cooler is effective for dry seasons and the regenerative evaporative cooler (REC) is an effective device for humid seasons in composite climate zones. Hence, the dual-mode evaporative cooler (a two-in-one device) is an intelligent choice for air conditioning, which can operate in both direct and regenerative modes depending on the seasonal climatic condition. The exergy and economic analyses of this novel device for global climatic conditions are performed to check the suitability in different regions of the world. An experimental prototype of a dual-mode evaporative cooler is developed and tested to validate the simulation model. The effectiveness, coefficient of performance, exergy destruction, exergy efficiency, operating cost, and specific total cost (STC) are evaluated for both (direct and regenerative) modes of operation. The annual and month-wise performances of dual-mode evaporative cooler have been assessed for five cities of international climate zones. The operating cost of both modes is compared by considering electricity charges in different countries. The dual-mode device is compared with the single-mode device as well. The specific cost is similar for both modes in most of the ASHRAE climatic zones. The present study reveals that significant energy and cost savings are possible by using the dual-mode evaporative cooler. Practical application: This article considers the application of a dual-mode evaporative cooler (direct as well as regenerative mode) in different climate zones and, through investigating the exergy and economic performances, allows designers and operators to understand the potential benefits of employing various operating modes in particular climates.

Analysis of Fault Detection Based on Least Squares Approach for BDS Integrity Monitoring

2021 ◽  
Author(s):  
Yi Zhang ◽  
Ershen Wang ◽  
Jing Guo ◽  
Yao Wang ◽  
Cen Wu ◽  
...  
Keyword(s):  
Fault Detection ◽  
Least Squares ◽  
Integrity Monitoring ◽  
Least Squares Approach

scholarly journals Analyses of the sensitivity of multi-constellation advanced receiver autonomous integrity monitoring vertical protection level availability to error parameters and a failure model over China

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401877619 ◽  
Author(s):  
Xueen Zheng ◽  
Ye Liu ◽  
Guochao Fan ◽  
Jing Zhao ◽  
Chengdong Xu
Keyword(s):  
Satellite System ◽  
Protection Level ◽  
Integrity Monitoring ◽  
System Service ◽  
Service Stations ◽  
Receiver Autonomous Integrity Monitoring ◽  
Global Navigation Satellite ◽  
Range Error ◽  
Monitoring Algorithm ◽  
Advanced Receiver

The availability of advanced receiver autonomous integrity monitoring for vertical guidance down to altitudes of 200 ft (LPV-200) is discussed using real satellite orbit/ephemeris data collected at eight international global navigation satellite system service stations across China. Analyses were conducted for the availability of multi-constellation advanced receiver autonomous integrity monitoring and multi-fault advanced receiver autonomous integrity monitoring, and the sensitivity of availability in response to changes in error model parameters (i.e. user range accuracy, user range error, Bias-Nom and Bias-Max) was used to compute the vertical protection level. The results demonstrated that advanced receiver autonomous integrity monitoring availability based on multiple constellations met the requirements of LPV-200 despite multiple-fault detections that reduced the availability of the advanced receiver autonomous integrity monitoring algorithm; the advanced receiver autonomous integrity monitoring availability thresholds of the user range error and Bias-Nom used for accuracy were more relevant to geographic information than the user range accuracy and Bias-Max used for integrity at the eight international global navigation satellite system service stations. Finally, the possibility of using the advanced receiver autonomous integrity monitoring algorithm for a Category III navigation standard is discussed using two sets of predicted errors, revealing that the algorithm could be used in 79% of China.

A Single-Cell-Gap Transflective Dual-Mode Liquid Crystal Display

2011 ◽  
Vol 181-182 ◽  
pp. 203-207
Author(s):  
Chao Ping Chen ◽  
Te Chen Chung ◽  
Tean Sen Jen ◽  
Xiao Jun Guo ◽  
Yi Kai Su
Keyword(s):  
Liquid Crystal ◽  
Single Cell ◽  
Liquid Crystal Display ◽  
Single Mode ◽  
Optical Performance ◽  
Dual Mode ◽  
Memory Ability ◽  
Gap Structure

A transflective dual-mode liquid crystal display (LCD) featuring single-cell-gap structure has been proposed in this paper. Unlike transflective single-mode LCDs, dual-mode LCD can work as either monostable transmissive or bistable reflective LCDs in a sense that two different modes of display are unified in one device. We have confirmed that it has not only desirable electro-optical performance but also longtime memory ability.

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