Journal of Global Positioning Systems最新文献

{"title":"Designing and Implementing a RFID-based Indoor Guidance System","authors":"C. C. Chang, P. Lou, H. Y. Chen","doi":"10.5081/JGPS.7.1.27","DOIUrl":"https://doi.org/10.5081/JGPS.7.1.27","url":null,"abstract":"Most people are not familiar with the indoor environment because most interior spaces are similar, and as such do not arouse the interest of most visitors. Although the GPS combined with the GIS has been broadly applied to many navigation applications, it might be still insufficient in an indoor environment where GPS signals are often severely obstructed. To meet the indoor requirements, the technique of RFID (Radio Frequency IDentification) was utilized to play an important locating role in the implementation of an indoor guidance system. The RFID tags, containing 1 KB capacity divided by 64 blocks, were adopted to accommodate the spatial-related information for working with the shortest routing for the system. By selecting the start and end points in the operation, the guidance system can suggest a direct, shortest distance, path. The locations of the passing points were identified and obtained by retrieving the spatial-related data from the tags next to the moving RFID reader. The guidance messages, including suggested path, modified path and moving directions, can be immediately presented to the users and arrive at their destination via the system’s graphic and voice interfaces. This guidance system has been comprehensively tested for its operation functions and was evaluated by a group of users, indicating that the average time for way finding in an indoor guidance trial can be efficiently reduced by 50%. This prototype for an indoor guidance system is expected to be capable of working on a portable device, such as a PDA or mobile phone, thereby extending its practical application.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125692273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Achieving Centimetre-level Positioning Accuracy in Urban Canyons with Locata Technology","authors":"J. Montillet, Xiaolin Meng, G. Roberts, A. Taha, C. Hancock, O. Ogundipe, J. Barnes","doi":"10.5081/JGPS.6.2.158","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.158","url":null,"abstract":"In 2005 The UK Department for Trade and Industry (DTI) commenced funding a project called Visualising Integrated Information on Buried Assets to Reduce Streetworks (VISTA). The project aims to precisely map buried assets (gas pipes, telecom cables, etc) and increase the efficiency of the process in challenging environments such as in urban canyons, where GPS fails to work or is not reliable enough to get a precise position. In this context the Institute of Engineering Surveying and Space Geodesy (IESSG) at the University of Nottingham purchased, at the beginning of 2007, a terrestrial network positioning system called Locata technology. This technology is developed by Locata Corporation Pty Ltd from Australia. Over the last five months researchers have carried out experiments with this new technology on the main campus of the University of Nottingham. The preliminary results show that LocataLites are a suitable technology to solve the positioning problems for the VISTA project. The overall accuracy is at the centimetre level for all points surveyed. Moreover, we underline in this paper the reliability and the flexibility of this new technology.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124080262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Potential of Locata Technology for Structural Monitoring Applications","authors":"J. Barnes, C. Rizos, A. Pahwa, N. Politi, J. V. Cranenbroeck","doi":"10.5081/JGPS.6.2.166","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.166","url":null,"abstract":"Locata technology is becoming part of Leica Geosystems solution for the structural monitoring applications such as bridges and dams. This paper assesses the performance of the Locata technology using a test Locata network (LocataNet) established at the University of New South Wales. Using this network a long term static tests and a simulated deformation movement test, with GPS as a comparison, were conducted. This paper described the LocataNet established at UNSW and presents the results and analysis of the tests conducted. Overall the paper demonstrates the suitability of Locata for structural deformation monitoring type applications (such as bridges and dams) where there is reduced or unavailable satellite coverage.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126765628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a Pseudo Quasi Zenith Satellite and Multipath Analysis Using an Airborne platform","authors":"T. Tsujii, H. Tomita, Y. Okuno, S. Kogure, M. Kishimoto, K. Okano, D. Manandhar, I. Petrovski, Masahiro Asako","doi":"10.5081/JGPS.6.2.126","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.126","url":null,"abstract":"Japan has been developing a new satellite based positioning system called Quasi-Zenith Satellite System (QZSS). Since improvement of positioning availability in urban area is one of the most important advantages of the QZSS, multipath mitigation is a key factor for the QZSS positioning system. Therefore, Japan Aerospace Exploration Agency (JAXA) and GNSS Inc. developed a pseudolite, which transmits the nextgeneration signal such as BOC(1,1), in order to evaluate the effect of multipath on the new signal. Flight experiments using a pseudo quasi-zenith satellite installed on a helicopter were conducted, and multipath mitigation by the BOC signal was demonstrated.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115376008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of the EGNOS Pseudolite System","authors":"Ruizhi Chen, Antti Hyttinen, Yuwei Chen","doi":"10.5081/JGPS.6.2.119","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.119","url":null,"abstract":"In order to access the Satellite Based Augmentation System (SBAS) service, the end user needs to have a direct line of sight to at least one of the Geostationary Earth Orbit (GEO) satellites transmitting the augmentation messages. This requirement is critical for users in environments such as city canyons, valleys and fjords since high buildings and mountains in the vicinity of the end user can easily block the lines of sight to the GEO satellites. The situation becomes worse at high latitudes because of the low elevation angles to the GEO satellites. Even a very low obstacle can block the lines of sight to the GEO satellites. This limitation reduces SBAS Signal in Space (SIS) availability significantly at high latitude especially for land applications. This paper presents a solution of transmitting the European Geostationary Navigation Overlay Service (EGNOS) SIS using a pseudolite. The EGNOS pseudolite functions in a similar way as a GEO satellite. It will provide not only a terrestrial-based solution for transmitting the EGNOS SIS, but also a ranging measurement for the navigation solution. The EGNOS pseudolite system mainly consists of a Master Control Station, an EGNOS Data Server, EGNOS pseudolites and the user terminal. A preliminary test on a surveyed site has been carried out to verify the functionalities of the system. The data set collected from the test has been processed with two scenarios: one with four GPS satellites, while the other with three GPS satellites plus an EGNOS pseudolite. Both data processing scenarios have similar satellite geometries. The test result shows that the positioning accuracies are similar for both scenarios.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130375357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive Tropospheric Delay Modelling in GPS/INS/Pseudolite Integration for Airborne Surveying","authors":"J. Wang, Jinling Wang","doi":"10.5081/JGPS.6.2.142","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.142","url":null,"abstract":"Integrated GPS/INS systems have been used for geo-referencing airborne surveying and mapping platforms. However, due to the limited constellation of GPS satellites and their geometric distribution, the accuracy of such integrated systems cannot meet the requirements of precise airborne surveying. This problem can be addressed by including additional GPS-like ranging signals transmitted from the ground-based pseudolites (PLs). As GPS measurement geometry could be strengthened dramatically by the PL augmentation, the accuracy and reliability of an integrated system can be improved, especially in the vertical component. Nevertheless, some modelling challenges exist in PLs augmentation. As PLs are relatively close to receivers, the unit vectors from a PL to he reference and rover receivers can be significantly different. PL tropospheric delay modelling errors cannot be effectively mitigated in a differencing procedure. Furthermore, PL signals propagate through the lower troposphere, where it is very difficult to accurately model the signal delay due to temporal and spatial variations of meteorological parameters. In this paper, an adaptive PL tropospheric delay modelling method is developed to reduce such modelling errors by estimating meteorological parameters in a model. The performance of this adaptive method isevaluated with field test data. The testing results haveshown that the PL tropospheric delay modelling error can be effectively mitigated by the proposed method.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124459203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autonomous Navigation Environment with Self-Calibrating Transceivers","authors":"S. S. tzer, S. Martin, M. V. Voithenberg","doi":"10.5081/JGPS.6.2.149","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.149","url":null,"abstract":"An operable navigation system which demonstrates successful self-calibration and precise local navigation has been developed by EADS Astrium. This paper presents the architecture of the autonomous navigation environment with the ability to calibrate itself as well as the results of field tests. The Self-calibrating autonomous Navigation Environment (SekaN) can be used as stand-alone navigation system for applications where satellite signals are not available or where autonomy and high precision is required. Cargo drop, navigation in canyons and open pit mines, indoor navigation and extraterrestrial navigation are just examples of possible applications. The self-calibrating feature of SekaN is of special interest in conflict areas where a temporary autonomous navigation environment has to be installed quickly and where it is not possible to calibrate the locations of the pseudolites a priori. Furthermore, the system can be operated as augmentation system to classical satellite navigation systems. Therefore a mixed mode has been introduced which allows for simultaneous tracking of both satellite signals and pseudolite signals. Referencing of the local coordinate system to e.g. WGS84 becomes possible. The SekaN system comprises the following HW units developed by EADS Astrium: at least 4 Transceivers (TCs), a Rover receiver (ROV) and a Master Control Station (MCS). A WLAN data link is used between the units. Each TC comprises a GNSS signal generator NSG 5100 which supports both GPS and Galileo signals and an Astriumspecific GPS/PSL receiver. The number of TCs in the network is scalable and dependent on the specific application of the SekaN. Various TC-array sizes are supported as the output power of the pseudolites can be varied in a wide range. The rover receiver positioning takes place at the MCS. However, several receivers may be registered at the MCS. The TCs are operated unsynchronized and differential concepts are applied to eliminate the clock errors. Presently the pulsed signals with pseudolite spreading codes at the GPS L1 and dummy navigation messages are used as navigation signals. As soon as low-cost Galileo receivers are available the system can be switched to any Galileo frequency band. In a batch process the exact locations of the TC TX-antennas are determined without any a priori knowledge of the geometric array configuration. The general idea behind the self-calibration algorithms is based on the solution algorithm for self-calibrating pseudolite arrays presented in (LeMaster and Rock, 2002). However, several modifications were necessary to adapt the algorithms to the SekaN system requirements. The rover which is used for data collection during the self-calibration process is designed as a Receiver-only module instead of a TC module. This makes the rover hardware less complex, smaller and lighter, but also complicates the self-calibration process. Self-differencing between the stationary TCs and the rover TC can no longer be applied","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"185 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131481468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Outdoor Positioning Results with Real Galileo Signals by Using the German Galileo Test and Development Environment - GATE","authors":"G. Heinrichs, E. Löhnert, E. Wittmann, R. Kaniuth","doi":"10.5081/JGPS.6.2.108","DOIUrl":"https://doi.org/10.5081/JGPS.6.2.108","url":null,"abstract":"Under the leadership of IFEN GmbH, the Galileo Test and Development Environment GATE is being built up in southern Germany by a consortium of several German companies and institutes on behalf of the German Aerospace Center (DLR) with funding by the German Federal Ministry of Education and Research. The performance tests regarding the user positioning performance will cover various test scenarios for static and dynamic cases. The tests will be performed in all available GATE operation modes with GATE signals only and in combination with GPS. Preliminary test during system testing phase showed already impressive positioning performance with dedicated signals and services. The paper gives an overview on the variant test scenarios and setups and illustrates the detailed hardware setup. An introduction in the GATE Backend Receiver Software, which computes the position solution, is presented. It describes the test procedures and shows the test results. Finally an evaluation on the different GATE services with respect to the positioning performance is presented.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"01 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129224807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precise Point Positioning Using Combined GPS and GLONASS Observations","authors":"C. Cai, Yang Gao","doi":"10.5081/JGPS.6.1.13","DOIUrl":"https://doi.org/10.5081/JGPS.6.1.13","url":null,"abstract":"Precise Point Positioning (PPP) is currently based on the processing of only GPS observations. Its positioning accuracy, availability and reliability are very dependent on the number of visible satellites, which is often insufficient in the environments such as urban canyons, mountain and open-pit mines areas. Even in the open area where sufficient GPS satellites are available, the accuracy and reliability could still be affected by poor satellite geometry. One possible way to increase the satellite signal availability and positioning reliability is to integrate GPS and GLONASS observations. Since the International GLONASS Experiment (IGEX-98) and the follow-on GLONASS Service Pilot Project (IGLOS), the GLONASS precise orbit and clock data have become available. A combined GPS and GLONASS PPP could therefore be implemented using GPS and GLONASS precise orbits and clock data. In this research, the positioning model of PPP using both GPS and GLONASS observations is described. The performance of the combined GPS and GLONASS PPP is assessed using the IGS tracking network observation data and the currently available precise GLONASS orbit and clock data. The positioning accuracy and convergence time are compared between GPS-only and combined GPS/GLONASS processing. The results have indicated an improvement on the position convergence time but correlates to the satellite geometry improvement. The results also indicate an improvement on the positioning accuracy by integrating GLONASS observations.","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115608102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a unified theory of GNSS ambiguity resolution","authors":"P. Teunissen","doi":"10.5081/JGPS.6.1.1","DOIUrl":"https://doi.org/10.5081/JGPS.6.1.1","url":null,"abstract":"In this invited contribution a brief review will be presented of the integer estimation theory as developed by the author over the last decade and which started with the introduction of the LAMBDA method in 1993. The re- view discusses three different, but closely related classes of ambiguity estimators. They are the integer estimators, the integer aperture estimators and the integer equivariant estimators. Integer estimators are integer aperture estima- tors and integer aperture estimators are integer equivari- ant estimators. The reverse is not necessarily true how- ever. Thus of the three types of estimators the integer es- timators are the most restrictive. Their pull-in regions are translational invariant, disjunct and they cover the ambi- guity space completely. Well-known examples are integer rounding, integer bootstrapping and integer least-squares. A less restrictive class of estimators is the class of inte- ger aperture estimators. Their pull-in regions only obey two of the three conditions. They are still translational invariant and disjunct, but they do not need to cover the ambiguity space completely. As a consequence the inte- ger aperture estimators are of a hybrid nature having either integer or non-integer outcomes. Examples of integer aper- ture estimators are the ratio-testimator and the difference- testimator. The class of integer equivariant estimators is the less restrictive of the three classes. These estimators only obey one of the three conditions, namely the condi- tion of being translational invariant. As a consequence the outcomes of integer equivariant estimators are always real- valued. For each of the three classes of estimators we also present the optimal estimator. Although the Gaussian case is usually assumed, the results are presented for an arbi- trary probability density function of the float solution. The optimal integer estimator in the Gaussian case is the inte- ger least-squares estimator. The optimality criterion used is that of maximizing the probability of correct integer es- timation, the so-called success rate. The optimal integer aperture estimator in the Gaussian case is the one which only returns the integer least-squares solution when the in- teger least-squares residual resides in the optimal aperture pull-in region. This region is governed by the probability density function of the float solution and by the probabil- ity density function of the integer least-squares residual. The aperture of the pull-in region is governed by a user- defined aperture parameter. The optimality criterion used is that of maximizing the probability of correct integer esti- mation given a fixed, user-defined, probability of incorrect integer estimation. The optimal integer aperture estimator becomes identical to the optimal integer estimator in case the success rate and the fail rate sum up to one. The best integer equivariant estimator is an infinite weighted sum of all integers. The weights are determined as ratios ","PeriodicalId":237555,"journal":{"name":"Journal of Global Positioning Systems","volume":"50 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130861583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}