检索结果-南通市图书馆

ambiguity resolution in Direction of Arrival Estimation with Linear Antenna Arrays Using Differential Geometry

Computers, Materials & Continua 2022年第1期70卷 581-599页

作者： Alamgir Safi Muhammad Asghar Khan Fahad Algarni Muhammad Adnan Aziz M.Irfan Uddin Insaf Ullah Tanweer Ahmad Cheema Department of Electronic Engineering ISRA UniversityIslamabad44000Pakistan Hamdard Institute of Engineering&Technology Islamabad44000Pakistan College of Computing and Information Technology University of BishaBishaSaudi Arabia Institute of Computing Kohat University of Science and TechnologyKohatPakistan

Linear antenna arrays(LAs)can be used to accurately predict the direction of arrival(DOAs)of various targets of interest in a given ***,under certain conditions,LA suffers from the problem of ambiguities among the angles of targets,which may result inmisinterpretation of such *** order to cope up with such ambiguities,various techniques have been ***,none of them fully resolved such a problem because of rank deficiency and high computational *** aimed to resolve such a problem by proposing an algorithm using differential *** proposed algorithm uses a specially designed doublet antenna array,which is made up of two individual linear *** angle observation models,ambiguous observation model(AOM)and estimated observation model(EOM),are derived for each individual *** ambiguous set of angles is contained in the AOM,which is obtained from the corresponding array elements using differential *** EOM for each array,on the other hand,contains estimated angles of all sources impinging signals on each array,as calculated by a direction-finding algorithm such as the genetic *** algorithm then contrasts the EOM of each array with its AOM,selecting the output of that array whose EOM has the minimum correlation with its corresponding *** comparison to existing techniques,the proposed algorithm improves estimation accuracy and has greater precision in antenna aperture selection,resulting in improved resolution capabilities and the potential to be used more widely in practical *** simulation results using MATLAB authenticates the effectiveness of the proposed algorithm.

关键词： Antenna array direction of arrival ambiguity resolution doublet antenna array ambiguous observation model estimated observation model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Performance investigation of LAMBDA and bootstrapping methods for PPP narrow-lane ambiguity resolution

引用

Geo-Spatial Information Science 2021年第4期24卷 604-614页

作者： Omer Faruk Atiz Sermet Ogutcu Salih Alcay Pan Li Ilkay Bugdayci Department of Geomatics Engineering Necmettin Erbakan UniversityKonyaTurkey Department of Geodesy and Remote Sensing German Research Centre for GeosciencesPotsdamGermany

Precise point positioning with ambiguity resolution(PPP-AR)is a powerful tool for geodetic and time-constrained applications that require high *** performance of PPP-AR highly depends on the reliability of the correct integer carrier-phase ambiguity *** this study,the performance of narrow-lane ambiguity resolution of PPP using the Least-squares ambiguity Decorrelation(LAMBDA)and bootstrapping methods is extensively investigated using real data from 55 IGS stations over one-month in *** PPP with 24-,12-,8-,4-,2-,1-and½-h sessions using two different cutoff angles(7°and 30°)was conducted with three PPP modes:***-float and two kinds of ambiguity-fixed PPP using the LAMBDA and bootstrapping methods for narrow-lane AR,*** results show that the LAMBDA method can produce more reliable results for 2 hour and shorter observation sessions com-pared with the bootstrapping method using a 7°cutoff *** a 30°cutoff angle,the LAMBDA method outperforms the bootstrapping method for observation sessions of 4 h and *** long observation times,the bootstrapping method produced much more accurate coordinates compared with the LAMBDA method without considering the wrong fixes *** results also show that occurrences of fixing the wrong integer ambiguities using the bootstrapping method are higher than that of the LAMBDA method.

关键词： ambiguity resolution narrow-lane Precise point positioning(PPP) LAMBDA bootstrapping

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Precise orbit determination of Haiyang‑2D using onboard BDS‑3 B1C/B2a observations with ambiguity resolution

引用

Satellite Navigation 2023年第3期4卷 167-184页

作者： Kecai Jiang Wenwen Li Min Li Jianghui Geng Haixia Lyu Qile Zhao Jingnan Liu GNSS Research Center Wuhan University129 Luoyu RoadWuhan 430079China Key Laboratory of Space Ocean Remote Sensing and Application Ministry of Natural Resources8 Dahui Temple RoadBeijing 10081China Collaborative Innovation Center of Geospatial Technology 129 Luoyu RoadWuhan 430079China Department of Land Surveying and Geo‑Informatics The Hong Kong Polytechnic University11 Yuk Choi RoadHung HomKowloonHong KongChina

The Haiyang-2D altimetry mission of China is one of the first Low Earth Orbit(LEO)satellites that can receive new B1C/B2a signals from the BeiDou-3 Navigation Satellite System(BDS-3)for Precise Orbit Determination(POD).In this work,the achievable accuracy of the single-receiver ambiguity resolution for onboard LEO satellites is studied based on the real measurements of new BDS-3 *** normal conditions,six BDS-3 satellites on average are ***,the multipath of the B1C/B2a code observations presents some patchy patterns that cause near-field variations with an amplitude of approximately 40 cm and deteriorate the ambiguity-fixed *** modeling those errors,for the B2a code,a remarkable reduction of 53%in the Root Mean Square(RMS)is achieved at high elevations,along with an increase of 8%in the ambiguity-fixed ***,an analysis of the onboard antenna’s phase center offsets reveals that when compared to the solutions with float ambiguities,the estimated values in the antenna’s Z direction in the solutions with fixed ambiguities are notably *** independent validation of the resulting POD using satellite laser ranging at 16 selected high-performance stations shows that the residuals are reduced by a minimum of 15.4%for ambiguity-fixed solutions with an RMS consistency of approximately 2.2 ***,when compared to the DORIS-derived orbits,a 4.3 cm 3D RMS consistency is achieved for the BDS-3-derived orbits,and the along-track bias is reduced from 2.9 to 0.4 cm using ambiguity fixing.

关键词： ambiguity resolution B1C/B2a Onboard BDS-3 Precise orbit determination Haiyang-2D

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Indirect-Inversion A lgorithm via Precise Integration for Ill-Conditioned Matrix in ambiguity resolution

引用

Journal of Shanghai Jiaotong university(Science) 2020年第6期25卷 762-768页

作者： ZHAO Fang SUN Jin ZHAO Jianjun YANG Libin School of Coast Guard Naval Aviation UniversityYantai 264001ShandongChina

Global navigation satellite system(GNSS)positioning depends on the correct integer ambiguity resolu-tion(AR).If the double difference equation for solving the float solution remains il-conditioned,often happening due to the environment complexity and the equipment mobility,the corrcct AR is difficult to ***-ing the il-conditioned problem,methods of modifying the equation cofficient matrix are widely applied,whose effects are heavily dependent on modifying ***,the direct inversion of the il-conditioned coef-ficient matrix can lead to a reduction in the accuracy and stability of the float *** solve the problem of il-conditioned matrix inversion and further improve the accuracy,the present study for the first time proves the positive definite symmetry of the coefficient matrix in AR model and employs precise integration method to the indirect inverse of cofficient *** model for the GNSS positioning and the general resolving strate-gies introduction are briefly *** indirect-inversion algorithm via precise integration for il-conditioned coefficient matrix is *** to the simulations and comparisons,the proposed strategy has higher precision and stability on foat solution,and less dependence on modifying parameters.

关键词： il-condition indirect-inversion ambiguity resolution precise integrat ion global navigation satellite system positioning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Satellite Selection Algorithm for Achieving High Reliability of ambiguity resolution with GPS and Beidou Constellations

A Satellite Selection Algorithm for Achieving High Reliabili...

引用

第四届中国卫星导航学术年会

作者： Jun Wang Yanming Feng Queensland University of Technology Brisbane

Reliability of carrier phase ambiguity resolution （AR） of an integer least-squares （ILS） problem depends on ambiguity success rate （ASR）, which in practice can be well approximated by the success probability of integer bootstrapping solutions. With the current GPS constellation, sufficiently high ASR of geometry-based model can only be achievable at certain percentage of time. As a result, high reliability of AR cannot be assured by the single constellation. In the event of dual constellations system （DCS）, for example, GPS and Beidou, which provide more satellites in view, users can expect significant performance benefits such as AR reliability and high precision positioning solutions. Simply using all the satellites in view for AR and positioning is a straightforward solution, but does not necessarily lead to high reliability as it is hoped. The paper presents an alternative approach that selects a subset of the visible satellites to achieve a higher reliability performance of the AR solutions in a multi-GNSS environment, instead of using all the satellites. Traditionally, satellite selection algorithms are mostly based on the position dilution of precision （PDOP） in order to meet accuracy requirements. In this contribution, some reliability criteria are introduced for GNSS satellite selection, and a novel satellite selection algorithm for reliable ambiguity resolution （SARA） is developed. The SARA algorithm allows receivers to select a subset of satellites for achieving high ASR such as above 0.99. Numerical results from a simulated dual constellation cases show that with the SARA procedure, the percentages of ASR values in excess of 0.99 and the percentages of ratio-test values passing the threshold 3 are both higher than those directly using all satellites in view, particularly in the case of dual-constellation, the percentages of ASRs （＞0.99） and ratio-test values （＞3） could be as high as 98.0% and 98.5% respectively, compared to 18.1% and 25.0% without satell

关键词： Satellite Selection Algorithm ambiguity success rate Reliability Dual-GNSS signals ambiguity resolution

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Single-epoch Integer ambiguity resolution for Long-Baseline RTK with Ionosphere and Troposphere Estimation

Single-epoch Integer Ambiguity Resolution for Long-Baseline ...

引用

第四届中国卫星导航学术年会

作者： Denghui Wang Chengfa Gao Shuguo Pan School of Transportation Southeast University School of Instrument Science and Engineering Southeast University

A new single-epoch ambiguity resolution for long baseline RTK, on the basis of the ionosphere-weighted model, is proposed in this paper, which is applicable to several hundred km baselines by using linear combination of the measurements, including the double-different wide-lane combination and ionosphere-free combination carrier-phase observation equations and UofC model. By the correct ambiguity and double-different atmosphere delay, the real-time atmosphere model was established to provide a predicted value for new-risen satellite. The establishment of real-time atmosphere predicted model, estimating the relative tropospheric zenith delay and the regional ionospheric parameters, is proved to have an acceptable accuracy. Test data from the multiple reference station GPS networks in Chongqing, consisting of 36 baselines from 40 kilometers to 350 kilometers, were used to evaluate the performance of the proposed approach. It is showed that the proposed algorithm can reduce the effect of the ionosphere and troposphere on the network AR and the true integer ambiguity could be achieved in a short time after the establishment of the predicted atmosphere model.

关键词： ambiguity resolution Network RTK UofC Real-time atmosphere model

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A New ambiguity resolution Method for PPP Using CORS Network and its Real-time Realization

A New Ambiguity Resolution Method for PPP Using CORS Network...

引用

第三届中国卫星导航学术年会

作者： Zou Xuan*, Tang Weiming, Shi Chuang, Liu Jingnan GNSS Research Center, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

The aim of this article is to improve the method of network RTK based on undifferenced （UD） observation corrections （abbreviated as URTK hereafter） by modeling the code UD observation residual. Thus rover could obtain more accurate approximate coordinate by code Single Point Positioning （SPP）, and then, speeding up the ambiguity convergence time. In addition, based on the improved URTK method, a three-step method for single-differenced （SD） ambiguity resolution of rover is proposed, which could solve the ionosphere-free （LC） ambiguities in several seconds. Lastly, based on the existing network RTK software and the real-time data stream simulator, the efficiency of our new methods have been proved with a real-time test. The results show that rover could gain rapid, cm-level and real-time Precise Point Positioning （PPP） service using CORS network.

关键词： GNSS Real-time ambiguity resolution PPP Network RTK Undifferenced corrections

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A Method of Medium/Long Baseline ambiguity resolution Based on BDS Triple-Frequency

A Method of Medium/Long Baseline Ambiguity Resolution Based ...

引用

第九届中国卫星导航学术年会

作者： Dengao Li Meng Shi Wenjing Li Jumin Zhao Junbing Cheng College of Information Engineering Taiyuan University of Technology

High precision positioning using carrier phase observations is the main method and approach of Beidou navigation satellite system(BDS) positioning. Especially, the ambiguity fixing has always been the focus, and it is always the key problem of the related research. In the medium/long baseline, the ionospheric delay error will affect the efficiency of ambiguity resolution seriously, and then affect the precision and efficiency of precise positioning. To solve this problem, this paper put forward a method of medium/long baseline ambiguity resolution based on the classical three-carrier ambiguity resolution(TCAR) model. To improve the reliability of wide-lane(WL) ambiguity fixing, a factor is introduced into the optimal linear combination for reducing noise, improve the reliability of wide-lane(WL) ambiguity fixing, and the ionospheric priori standard deviation is used to minimize the effect of the length of the baseline. In order to verify the feasibility and effectiveness of the algorithm, the proposed algorithm is compared with the classical TCAR algorithm in several aspects such as the ambiguity fixed success rate. The results show that the proposed algorithm has the highest success rate in the case of medium/long baseline, and can fix the ambiguity instantly.

关键词： ambiguity resolution TCAR BDS Triple-frequency Medium/long baseline Ionospheric delay

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Ionosphere-free Combinations for Triple-frequency GNSS with Application in Rapid ambiguity resolution over Medium-Long Baselines

Ionosphere-free Combinations for Triple-frequency GNSS with ...

引用

第三届中国卫星导航学术年会

作者： Li Jinlong1, Yang Yuanxi2, Xu Junyi1, He Haibo3, Guo Hairong31 Institute of Surveying and Mapping, Information Engineering University, Zhengzhou 450052, China 2 Xi’an Research Institute of Surveying and Mapping, Xi’an 7100545, China 3 Beijing Global Information Center of Application and Exploitation, Beijing 100094, China

Aiming at rapid precise positioning by triple-frequency Global Navigation Satellite System （GNSS） over medium-long baselines, the application of triple-frequency ionosphere-free combinations in ambiguity resolution and precise positioning is analyzed. The analytical expression of linear coefficients of them is deduced, and the influences of various errors on ambiguity resolution and precise positioning are evaluated. Considering that the wavelength of optimal ionosphere-free combinations is too small, a method for decomposing the ambiguity of triple-frequency ionosphere-free combinations is presented, and the formula to calculate the virtual wavelength of them is given. In addition, an algorithm for narrow-lane ambiguity resolution is proposed, which is immune to systematic errors. It is proved that the resolutions of narrow-lane ambiguity by this proposed method are equal, with any wide-lane combinations that the sum of linear coefficients of them is equal to zero.

关键词： triple-frequency ionosphere-free combination geometry-free and ionosphere-free combination medium-long baseline ambiguity resolution

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Single Epoch ambiguity resolution Based on FirCAR

Single Epoch Ambiguity Resolution Based on FirCAR

引用

第三届中国卫星导航学术年会

作者： Wei Feng1,Dingfa Huang1,Yan Li1,Meng Li11School of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 610031,Sichuan,China

Single epoch ambiguity resolution（AR） is affected by the pseudorange accuracy,especially for the situation with a few satellites *** such case,the float solution is not always good enough to resolve ambiguity epoch by epoch,and leads to a lower success *** increase the success rate of single epoch AR,the ratio value in ambiguity validation procedure could be relaxed to a lower value,while the precise stochastic model of GNSS observation is *** socalled FirCAR（dual-Frequency integer relationship Constrained ambiguity resolution） method is able to resolve ambiguities for high-elevation satellites using dual-frequency data in short baseline,and improve the accuracy of the float *** methods are used to resolve the unfixed ambiguities depending on the accuracy of the float *** off algorithm is adopted when each float ambiguity is close enough to an ***,ambiguity search algorithm is *** are conducted in static and kinematic mode using GPS measurements,and the experimental results indicate that:higher success rates are achieved with the proposed FirCAR method compared with the conventional search algorithm for single epoch AR,even only a few satellites are available;more than 70% epochs available are fixed by rounding off algorithm throughout the period of 24 h experiments.

关键词： GNSS ambiguity resolution Single epoch FirCAR ROUND

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：