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Mannucci, A.

Publications and source records attributed to Mannucci, A..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Sudden ionospheric delay decorrelation and its impact on WAAS

In the absence of selective availability, the ionosphere represents the largest source of positioning error for single-frequency users of the GPS. In differential GPS systems such as the Wide Angle Augmentation System, vertical ionospheric delays are modeled at regularly-spaced intervals in latitude and longitude. The broadcast bound on the error at each of these points is designated the grid ionospheric vertical erorr (GIVE). A critical integrity requirement of WAAS is that the broadcast GIVE bounds residual error with a very high degree of confidence.

ionosphere WAAS GPS↗
NASA NTRS2002

Sudden ionospheric delay decorrelation and its impact on WAAS

We report a methodology for assessing the impact on WAAS posed by a sudden increase in the level of ionospheric disturbance. The methodology is based upon the forming an estimate of the probability P(D) that a WAAS user will confront a sudden increase in the level of ionospheric disturbance following a period of relative calm. By restricting the tabulation of fit residuals to only those fits where the spatial coverage of the fit points is sufficiently good, we have determined a limiting upper bound of P(D) to be 2x10(sup -6).

ionosphere WAAS GPS↗
NASA NTRS2000

Ionospheric specification algorithms for precise GPS-based aircraft navigation

We present a technique for converting real-time total electron content (TEC) measurements into gridded vertical delay corrections at the GPS L***sub***1 frequency, which will be broadcast to users every 5 min via geosynchronous satellite. Users will convert these delays to slant corrections for their own particular lines of sight to GPS satellites. To preserve user safety, estimates of the error in the user delay corrections will also be broadcast.

Global↗
NASA NTRS1999

Assessment of Global TEC Mapping Using a Three-Dimensional Electron Density Model

Dual-frequency transmissions from the Global Positioning System satellites can be used to measure and map ionospheric total electron content (TEC) on global scales. Using data exclusively from ground-based GPS networks, global ionosphere mapping has been successfully applied using either two or three dimensional techniques.

Global↗
NASA NTRS1999

GPS and Ionosphere

The Global Positioning System (GPS) constellation of satellites is revolutionizing the science and technology of the Earth's ionosphere.

Global Positioning System (GPS) ionosphere total e↗