نتایج جستجو برای: GPS TEC

تعداد نتایج: 34383  

ژورنال: :علوم و فنون نقشه برداری 0
ناصر عبدی n. abdi گروه مهندسی نقشه برداری - پردیس دانشکده های فنی - دانشگاه تهران حمیدرضا نانکلی h. nankali ادارۀ ژئودزی و ژئودینامیک - سازمان نقشه برداری کشور

طی سالیان گذشته، استفاده از gps به عنوان یک ابزار منحصربه فرد، در مطالعۀ چگونگی گذر امواج الکترومغناطیس ازلایه های مختلف اتمسفر به خصوص یونسفر مطرح بوده است. در حال حاضر یونسفر عمده ترین منبع خطا در موقعیت یابی با gps محسوب-گردیده و میزان تاًثیر آن روی انتشار موج بستگی به مقدار tec و فرکانس سیگنال دارد. در این مقاله تغییرات زمانی-مکانی tec در ایران با استفاده از مشاهدات حدود 40 ایستگاه ipgn مورد...

2009
John Bosco Habarulema Lee-Anne McKinnell Pierre Cilliers Ben Opperman

The Global Positioning System (GPS) makes it possible to study the dynamics of the ionosphere by supplementing ionospheric studies carried out using various techniques including ionosondes, incoherent scatter radars and low earth orbit satellites. Total electron content derived from GPS data (GPS TEC) is a key parameter characterising the ionosphere. Its time evolution provides an indication of...

1998
G. Ru

We compare TEC measurements from the NASA Radar Altimeter and DORIS instrument on board TOPEX/POSEIDON with GPS TEC estimates , and evaluate diierent GPS data analysis strategies. We verify that global tomographic GPS analysis using a voxel grid is well suited for ionospheric calibration of altimeters. We show that a 1-day t of 20-second-averaged NRA ionospheric correction data versus GPS tomog...

2009
N. M. Pedatella J. Lei K. M. Larson J. M. Forbes

[1] The long-duration positive ionospheric storm effect that occurred on 15 December 2006 is investigated using a combination of ground-based Global Positioning System (GPS) total electron content (TEC), TOPEX and Jason-1 TEC, and topside ionosphere/ plasmasphere TEC, GPS radio occultation, and tiny ionospheric photometer (TIP) observations from the Constellation Observing System for Meteorolog...

2009
AZAMI ZAHARIM

GPS receivers have been profitably employed by researchers for investigations into ionospheric and atmospheric science. However, a number of improvements in measurement accuracy are necessary for today’s applications. The ionosphere has practical importance in GPS applications because it influences transionospheric radio wave propagation. Total Electron Content (TEC) is one of the parameters of...

Journal: :IEEE Trans. Geoscience and Remote Sensing 1997
William S. Schreiner Robert E. Markin George H. Born

-This study is a preliminary analysis of the accuracy of various ionosphere models to correct single frequency altimeter height measurements for ionospheric path delay. In particular, research focused on adjusting empir/cal and parameterized ionosphere models in the parameterized real-time ionospheric specification modal (PRISM) 1.2 using total electron content (TEC) data from the global positi...

2006
Michael Mendillo

[1] The ionosphere’s total electron content (TEC) is a parameter widely used in studies of the near-Earth plasma environment. The scientific use of TEC appeared early in the artificial satellite era, and among its many contributions were fundamental insights into how the ionosphere responds to geomagnetic storms. While many excellent reviews of solar-terrestrial disturbances exist in the litera...

2013
Dhiraj Sunehra

The positional accuracy of Global Positioning System (GPS) is affected by several errors, the most predominant error being the ionospheric delay. This delay is proportional to the total electron content (TEC). The dual frequency GPS observables can be used to estimate the TEC. The line-of-sight TEC estimated from dual frequency GPS data is corrupted by the instrumental biases of the GPS satelli...

2011
W. Suparta M. A. Mohd M. S. Jit Singh B. Yatim T. Motoba N. Sato A. Kadokura

This paper observed the interhemispheric conjugate auroral activity occurred on 21 September 2009. The GPS derived ionospheric total electron content (TEC) during a weak substorm interval recorded at interhemispheric conjugate points at Husafell in Iceland and Syowa in Antarctica is investigated to look at their signatures on the auroral features. Selection of all-sky camera (ASC) images and ke...

2011
A. Paul T. Das S. Ray A. Das D. Bhowmick

Dual-frequency GPS TEC monitors have been used to study the response of the ionosphere to the solar eclipses of 22 July 2009 and 15 January 2010. The receivers were located at three stations, Calcutta, Kharagpur and Baharampore which are situated outside the umbra zone in the Indian longitude sector with each baseline being ∼200 km. Effects of obscuration of the solar disc were noted in the amb...

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