53 Result(s)
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Article
Ionospheric TEC predictions over a local area GPS reference network
Single layer ionosphere models are frequently used for ionospheric modeling and estimation using GPS measurements from a network of GPS reference stations. However, the accuracies of single layer models are in...
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Article
Identification of GPS positioning solutions deteriorated by signal degradations using a fuzzy inference system
The accuracy of GPS positioning based on pseudorange measurements under signal degradation environments is limited by poor satellite geometry and signal distortions due to diffraction and multipath. As a resul...
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Article
Ionospheric modeling using GPS data
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Article
Open AccessA study of smoothed TEC precision inferred from GPS measurements
The availability of a large amount of TEC data derived from dual frequency GPS measurements observed by GPS reference networks provides a great opportunity for ionosphere studies. In order to obtain better acc...
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Article
A method to improve the alignment performance for GPS-IMU System
Zero velocity and zero east component of rotation rate relative to local geographic frame have been traditionally applied as measurements for fine alignment of a GPS-IMU system. The performance of the fine ali...
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Chapter and Conference Paper
Geodetic Sensor Systems and Sensor Networks: Positioning and Applications
This contribution focuses on geodetic sensor systems and sensor networks for positioning and applications. The key problems in this area will be addressed together with an overview of applications. Global Navi...
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Article
Modeling and assessment of combined GPS/GLONASS precise point positioning
A combination of GPS and GLONASS observations can offer improved reliability, availability and accuracy for precise point positioning (PPP). We present and analyze a combined GPS/GLONASS PPP model, including b...
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Article
Open AccessLocal troposphere augmentation for real-time precise point positioning
The IGS real-time service (RTS) enables real-time precise point positioning (PPP) at a global scale. A long convergence time however is still a challenging factor. In order to reduce the convergence time, exte...
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Article
A comparison of three PPP integer ambiguity resolution methods
Precise point positioning (PPP) integer ambiguity resolution with a single receiver can be achieved using advanced satellite augmentation corrections. Several PPP integer ambiguity resolution methods have been...
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Article
Modeling the integrated roles of insurance and retrofit in managing natural disaster risk: a multi-stakeholder perspective
This paper introduces a new modeling framework to understand and improve regional natural disaster risk management in the USA, including the interactions among key stakeholders and between the two important ri...
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Article
An impact analysis of arc length on orbit prediction and clock estimation for PPP ambiguity resolution
Real-time precise orbit and clock products are crucial for real-time high-precision precise point positioning (PPP). The key for precise orbit prediction is to precisely determine the initial conditions (satel...
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Article
Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation
Global Positioning System (GPS) has become a cost-effective tool to determine troposphere zenith total delay (ZTD) with accuracy comparable to other atmospheric sensors such as the radiosonde, the water vapor ...
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Article
Improved PPP ambiguity resolution by COES FCB estimation
Precise point positioning (PPP) integer ambiguity resolution is able to significantly improve the positioning accuracy with the correction of fractional cycle biases (FCBs) by shortening the time to first fix ...
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Article
Effect and mitigation of oscillator vibration-induced phase noise on carrier phase tracking
The influence of vibration-induced oscillator phase noise on carrier phase tracking of a GNSS receiver is analyzed. We show that when the oscillator is vibrating, the vibration-induced oscillator noise is incr...
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Article
An approach to GPS clock prediction for real-time PPP during outages of RTS stream
The international GNSS service (IGS) has been providing an open-access real-time service (RTS) since 2013, which allows users to carry out real-time precise point positioning (RT-PPP). As the availability of R...
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Chapter and Conference Paper
A New Method for Real-Time PPP Correction Updates
Real-time Precise Point Positioning (PPP) is expected to find more and more applications with various precise satellite orbit and clock products becoming more easily and reliably available. A crucial aspect fo...
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Article
Theoretical analysis of unambiguous 2-D tracking loop performance for band-limited BOC signals
Code-tracking accuracy, an important attribute of receiver performance assessment, depends both on characteristics of the ranging signal being tracked and on the structure of the tracking channel. The implemen...
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Article
Real-time carrier phase multipath detection based on dual-frequency C/N0 data
Since carrier phase multipath cannot be easily captured or mitigated, especially in real-time and kinematic applications, it is necessary to assess the multipath significance. We propose a real-time multipath ...
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Article
Quality assessment of CNES real-time ionospheric products
Real-time single-frequency precise point positioning (RT-SF-PPP) has become a desired positioning approach because it can achieve high positioning accuracy with a low-cost global navigation satellite system (G...
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Article
Improvement of carrier phase tracking in high dynamics conditions using an adaptive joint vector tracking architecture
The standard vector phase-locked loop (VPLL) with fixed pre-defined process noise covariance matrix usually loses lock when the receiver experiences high dynamic conditions. Two adaptive Kalman filters (KF), w...
