نتایج جستجو برای: برآورد تروپوسفر با سامانه gnss

تعداد نتایج: 677612  

2017
Patrick Henkel

Magnetometers provide compass information, and are widely used for navigation, orientation and alignment of objects. As magnetometers are affected by sensor biases and eventually by systematic distortions of the Earth magnetic field, a calibration is needed. In this paper, a method for calibration of magnetometers with three Global Navigation Satellite System (GNSS) receivers is presented. We p...

2013
Anup Dhital Jared Bancroft Gérard Lachapelle

In natural and urban canyon environments, Global Navigation Satellite System (GNSS) signals suffer from various challenges such as signal multipath, limited or lack of signal availability and poor geometry. Inertial sensors are often employed to improve the solution continuity under poor GNSS signal quality and availability conditions. Various fault detection schemes have been proposed in the l...

2010
Binghao Li Jiahuang Zhang Andrew G. Dempster Chris Rizos

Assisted-Global Navigation Satellite Systems (A-GNSS), or Assisted-Global Positioning Systems (A-GPS) in particular, are now commonly accepted as an effective way to reduce the time-to-first-fix (TTFF) in GNSS-unfriendly environments, e.g. in areas of weak GNSS signals. Today’s location-based service (LBS) devices such as GPS-enabled mobile phones and personal digital assistants (PDA) rely on A...

2010
W. E. Featherstone J. F. Kirby C. Hirt M. S. Filmer S. J. Claessens

AUSGeoid09 is the new Australia-wide gravimetric quasigeoid model that has been a posteriori fitted to the Australian Height Datum (AHD) so as to provide a product that is practically useful for the more direct determination of AHD heights from Global Navigation Satellite Systems (GNSS). This approach is necessary because the AHD is predominantly a third-order vertical datum that contains a ~1 ...

2017
C. K. Toth Z. Koppanyi D. Grejner-Brzezinska

Acquiring geospatial data in GNSS compromised environments remains a problem in mapping and positioning in general. Urban canyons, heavily vegetated areas, indoor environments represent different levels of GNSS signal availability from weak to no signal reception. Even outdoors, with multiple GNSS systems, with an ever-increasing number of satellites, there are many situations with limited or n...

2013
Vincenzo Capuano Cyril Botteron Pierre-André Farine

Global Navigation Satellite Systems (GNSSs) such as GPS, GLONASS, and the future Galileo and BeiDou, have demonstrated to be a valid and efficient system for various space applications in Low Earth Orbit (LEO), such as spacecraft orbit and attitude determination, rendezvous and formation flight of two or more spacecrafts, and timing synchronization. A GNSS presents a number of significant advan...

ژورنال: فیزیک زمین و فضا 2020

Total electron content (TEC) and GNSS positioning error over two Nigeria GNSS stations (CLBR: Latitude; 4.9503°E, Longitude; 8.3514°N, FUTY: Latitude; 9.3497°E, Longitude; 12.4978°N) were studied during the geomagnetic storms of March 17, 2015 minimum Dst (Disturbed storm time) -223nT and that of March 17, 2013 minimum Dst of -132nT (the St. Patrick’s...

Journal: :ERCIM News 2013
Xihui Chen Carlo Harpes Gabriele Lenzini Sjouke Mauw Jun Pang

11 Driving across unknown routes used to be stressful owing to the almost inevitable problem of getting lost. Thanks to Global Navigation Satellite Systems (GNSS) navigation devices, such problems are now in the past. These devices have revolutionized how we move: they guide us not only in unknown places but also within our own neighbourhoods. Our growing dependence on them to find our way is r...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1382

افزایش روزافزون کاربرد‏‎gis‎‏ در تعیین موقعیت و ناوبری لزوم دستیابی به دقت بالاتر در موقعیت را ایجاب می کند. مشاهدات ‏‎gps‎‏ مانند هر مشاهده دیگری دارای اثرات خطاهای اتفاقی و سیستماتیک از منابع مختلفی می باشد. از عمده ترین این خطاها، خطاهای ساعت گیرنده و ماهواره خطای مداری، خطای چند مسیره شدن سیگنال ‏‎multipath‎‏ ، خطاهای جوی شامل انکسار یونسفریک و تروپوسفریک و خطای نویز گیرنده می باشند. اما آن...

2012
P.J.G. Teunissen

In this contribution we analyse the possible nonuniqueness in the least-squares solution of the GNSS carrier-phase compass model. It is shown that this lack of uniqueness may manifest itself in the fixed baseline estimator and therefore in the GNSS compass readings. We present the conditions under which nonuniqueness occurs and give explicit expressions for these nonunique least-squares solutions.

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