Engineering topics

Nesterczuk, G.

Publications and source records attributed to Nesterczuk, G..

7 records

NASA NTRS1983

Equatorial long waves in geostationary satellite observations and in a multichannel sea surface temperature analysis

Geostationary satellite observations of a zonally oriented sea surface temperature front in the eastern equatorial Pacific were made between 1975 and 1981. Long waves appeared along the front mainly during the summer and fall, except during 1976, the year of an El Nino. The waves have averaged periods of 25 days and wavelengths of 1000 km. At the end of 1981, the long waves also were detected in a new sea surface temperature analysis based on multichannel infrared measurements from a polar-orbiting satellite. This quantitative analysis may improve the ability to resolve low-frequency equatorial wave motions from satellite observations.

Legeckis, R.↗

NASA NTRS1981

Ionospheric propagation correction modeling for satellite altimeters

The theoretical basis and avaliable accuracy verifications were reviewed and compared for ionospheric correction procedures based on a global ionsopheric model driven by solar flux, and a technique in which measured electron content (using Faraday rotation measurements) for one path is mapped into corrections for a hemisphere. For these two techniques, RMS errors for correcting satellite altimeters data (at 14 GHz) are estimated to be 12 cm and 3 cm, respectively. On the basis of global accuracy and reliability after implementation, the solar flux model is recommended.

Nesterczuk, G.↗

NASA NTRS1976

Ionospheric Refraction Corrections in the GTDS for Satellite-To-Satellite Tracking Data

In satellite-to-satellite tracking (SST) geographic as well as diurnal ionospheric effects must be contended with, for the line of sight between satellites can cross a day-night interface or lie within the equatorial ionosphere. These various effects were examined and a method of computing ionospheric refraction corrections to range and range rate measurements with sufficient accuracy were devised to be used in orbit determinations. The Bent Ionospheric Model is used for SST refraction corrections. Making use of this model a method of computing corrections through large ionospheric gradients was devised and implemented into the Goddard Trajectory Determination System. The various considerations taken in designing and implementing this SST refraction correction algorithm are reported.

Nesterczuk, G.↗

NASA NTRS1976

Line-of-sight electron density gradients as deduced from an empirical ionospheric model

A topside ionospheric model (Bent Ionospheric Model) was developed for an accurate prediction of integrated total electron content (TEC), from a global data acquired for the years 1962 to 1969. In this paper the effects of line-of-sight electron density gradients on ground to satellite measurements are discussed. The results of analyses show that in the presence of increasing density gradients, deduced values of vertical electron content or slab thicknesses will be too large, while for decreasing gradients these values will be smaller than they should be.

Nesterczuk, G.↗

NASA NTRS1974

Investigation of the ionospheric Faraday rotation for use in orbit corrections

The possibility of mapping the Faraday factors on a worldwide basis was examined as a simple method of representing the conversion factors for any possible user. However, this does not seem feasible. The complex relationship between the true magnetic coordinates and the geographic latitude, longitude, and azimuth angles eliminates the possibility of setting up some simple tables that would yield worldwide results of sufficient accuracy. Tabular results for specific stations can easily be produced or could be represented in graphic form.

Llewellyn, S. K.↗

NASA NTRS1974

Explanation of the computer listings of Faraday factors for INTASAT users

Using a simplified form of the Appleton-Hartree formula for the phase refractive index, a relationship was obtained between the Faraday rotation angle along the angular path and the total electron content along the vertical path, intersecting the angular at the height of maximum electron density. Using the second mean value theorem of integration, the function B cosine theta second chi was removed from under the integral sign and replaced by a 'mean' value. The mean value factors were printed on the computer listing for 39 stations receiving signals from the INTASAT satellite during the specified time period. The data is presented by station and date. Graphs are included to demonstrate the variation of the Faraday factor with local time and season, with magnetic latitude, elevation and azimuth angles. Other topics discussed include a description of the bent ionospheric model, the earth's magnetic field model, and the sample computer listing.

Nesterczuk, G.↗

NASA NTRS1971

NASA-GSFC ionospheric corrections to satellite tracking data

An overview is presented of the development, verification, and recent implementation of the NASA-GSFC ionospheric model for satellite tracking data corrections. This model was incorporated into the Goddard Trajectory Determination System which is providing continuous trajectory computation support for the lunar orbiting Radio Astronomy Explorer-B launched on 10 June 1973.

Schmid, P. E.↗