Search results for: Urbano Tancredi
GPS Solutions > 2018 > 22 > 2 > 1-14
Advances in Space Research > 2011 > 48 > 3 > 507-520
Acta Astronautica > 2010 > 66 > 9-10 > 1388-1398
Acta Astronautica > 2005 > 56 > 1-2 > 285-296
article
Ionospheric delays compensation is a mandatory step for precise absolute and relative positioning of Low Earth Orbit Satellites (LEO) by GPS measurements. The most frequently used ionosphere model for real-time GPS-based navigation in LEO is an isotropic model proposed by Lear, which uses the Vertical Total Electron Content (VTEC) above the receiver and a mapping function for TEC evaluation along...
chapter
The problem of relative navigation of formation flying satellites for remote-sensing applications is addressed in this chapter. Specifically, a filtering scheme is proposed for the determination of relative position and velocity in real time, relying on the cascade combination of an Extended Kalman Filter and a kinematic filter. Since high measurement accuracy is desired both filters process dual-frequency...
chapter
The ionosphere is commonly divided into the portion below (bottomside) and above (topside) the region at which peak values of electron density occur. Topside ionospheric modeling is a challenging problem because of the limited data available. Indeed, the more intense peak ionization region, or bottomside ionosphere, dominates the effects observable from ground stations. High-altitude ionosondes, such...
chapter
This paper presents a technique for on-the-fly rejection of GPS pseudorange data outliers. It is developed for applications in whom high accuracy navigation is needed in real time, as for the relative positioning of satellites in Low Earth Orbit. The proposed technique relies on two metrics screening the residual ranging errors in the Zero-Difference and Single-Difference pseudorange measurements...
article
GPS relative navigation filters could benefit notably from an accurate modeling of the ionospheric delays, especially over large baselines (>100km) where double difference delays can be higher than several carrier wavelengths. This paper analyzes the capability of ionospheric path delay models proposed for spaceborne GPS receivers in predicting both zero-difference and double difference ionospheric...
article
The present paper aims at improving the efficiency of the robustness analyses of flight control laws with respect to conventional techniques, especially when applied to vehicles following time-varying reference trajectories, such as in an atmospheric re-entry. A nonlinear robustness criterion is proposed, stemming from the practical stability framework, which allows dealing effectively with such cases...
article
The evolution of the aerospace field has pushed the importance of cost-effective development of space platforms. The high-risk levels related to new technology allow universities to have an important role in improving the cost effectiveness of the hardware design, development and testing. In this frame, the Second University of Naples space technology program is described, outlining benefits and drawbacks...
Sending the report failed
Submitting the report failed. Please, try again. If the error persists, contact the administrator by writing to support@infona.pl.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.