Topic
GNSS augmentation
About: GNSS augmentation is a research topic. Over the lifetime, 2478 publications have been published within this topic receiving 28513 citations. The topic is also known as: SBAS & Satellite Based Augmentation System.
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TL;DR: An onboard navigation system for a space vehicle as it is inserted into a geostationary orbit using a low-thrust engine is considered and the justification of its architecture and operation algorithms are justified, based on requirements for the accuracy of the navigation problem solution.
Abstract: An onboard navigation system for a space vehicle (satellite) as it is inserted into a geostationary orbit using a low-thrust engine is considered. The navigation system uses optoelectronic Earth, Sun, and star sensors and a multichannel GNSS signal receiver. The purpose of the study is to form a general design of the integrated navigation system, including the justification of its architecture and operation algorithms, based on requirements for the accuracy of the navigation problem solution. To integrate various measurements, a quasilinear Kalman filter and its special "scalar" modification are used. The vector to be estimated onboard the spacecraft consists of the coordinate and velocity components, the attitude of its body axis, and the attitude and actual thrust of its main thruster. Instrument sensor errors are considered as uncontrollable factors. The main tool for the analysis of the navigation system error is simulation, which is performed using dedicated software developed using the object-oriented paradigm.
9 citations
TL;DR: It is illustrated that the local oscillator can be a limiting factor in the tracking threshold when the receiver is subject to pedestrian or vehicular dynamics, and a novel feed-forward compensation technique is presented, which draws upon the inertial measurement unit resources of the receiver to alleviate these detrimental oscillator-based effects.
Abstract: In this paper the influence of oscillator g sensitivity on carrier-phase tracking performance in a global navigation satellite-system receiver is examined. It is illustrated that the local oscillator can be a limiting factor in the tracking threshold when the receiver is subject to pedestrian or vehicular dynamics. A novel feed-forward compensation technique is presented, which draws upon the inertial measurement unit resources of the receiver to alleviate these detrimental oscillator-based effects. Performance evaluation considered live global navigation satellite-system signals, a range of consumer-grade oscillators, and both high-quality and Microelectromechanical systems (MEMS)-grade inertial measurement units, in both pedestrian and vehicular operating environments. The results show that the process-noise spectral density corresponding to the signal acceleration state of the Kalman-filter-based tracker can be reduced significantly with compensation. It is also shown that three-dimensional velocity error reduces from 0.17 to 0.06 m/s with compensation.
9 citations
TL;DR: Wang et al. as discussed by the authors presented a novel interpretation approach to analyze the initial time-series InSAR analysis results to efficiently identify potential landslide areas from the ascending-descending SAR datasets.
Abstract: The technique of interferometric synthetic aperture radar (InSAR) is increasingly employed for landslide detection over large areas, even though the limitations of initial InSAR analysis results have been well acknowledged. Steep terrain in mountainous areas may cause geometric distortions of SAR images, which could affect the accuracy of InSAR analysis results. In addition, due to the existence of massive ground deformation points in the initial InSAR analysis results, accurate landslide recognition from the initial results is challenging. To efficiently identify potential landslide areas from the ascending–descending SAR datasets, this paper presents a novel interpretation approach to analyze the initial time-series InSAR analysis results. Within the context of the proposed approach, SAR visibility analysis, conversion analysis of deformation rates obtained from the time-series InSAR analysis, and spatial analysis and statistics tools for cluster extraction are incorporated. The effectiveness of the proposed approach is illustrated through a case study of landslide identification in Danba, a county in Sichuan, China. The potential landslide regions in the study area are identified based on the interpretation of small baseline subset InSAR (SBAS-InSAR) results, obtained with ascending–descending Sentinel-1A datasets. Finally, on the basis of the field survey results, a total of 21 landslides are detected in the potential landslide regions identified, through which the results obtained from the proposed interpretation approach are tested.
9 citations
05 May 2008
TL;DR: The paper proposes multi system solution which utilizes navigation and communication systems and signals and the experimental software receiver is described as development tool of such combined system.
Abstract: High demands on mobile user positioning cannot be satisfied by single navigation system. The paper proposes multi system solution which utilizes navigation and communication systems and signals. The experimental software receiver is described as development tool of such combined system. The proposed receiver consist of three GNSS RF front ends of bandwidth of 24 MHz tunable to any navigation frequency from 1 to 2 GHz and one DVB-T(H) tuner. The programmable receiver hardware is based on FPGA and PC workstation which communicate each other via Gigabit Ethernet. In the second part of this paper we are presenting methods of estimation of time of arrival of OFDM (Orthogonal Frequency Division Multiplex) signal. Described estimation algorithm is used in the DVB-T(H) (Digital Video Broadcasting - Terrestrial) receiver which can be used for navigation or for support of satellite navigation receivers. The last part of this paper describes our results of experiments with DVB-T(H) navigation. They were obtained in various environments (urban, suburban, etc.) including indoor environment.
9 citations
Patent•
20 Feb 2009
TL;DR: In this article, a method of communicating satellite tracking information among a network of global navigation satellite system receivers is described, which includes determining at a first GNSS receiver which satellites in a constellation of satellites have been continuously tracked over a preceding selected time period, and for each such satellite determining its elevation with respect to the zenith.
Abstract: A method of communicating satellite tracking information among a network of global navigation satellite system receivers is described. The method includes determining at a first GNSS receiver which satellites in a constellation of satellites have been continuously tracked over a preceding selected time period, and for each such satellite determining its elevation with respect to the zenith. Only the elevation value for the lowest satellite in the set of satellites for which all satellites of higher elevation values have been continuously tracked over the selected time period is then transmitted to the second GNSS receiver. That receiver can then reconstruct the set of satellites which have been continuously tracked.
9 citations