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Start Over Descriptor "Group delay" Language russian
2 results on '"Group delay"'

1. Local phase center hodograph of radiating element’s navigation antenna Glonass

Author

N. V. Morozov, Yu. I. Choni, and I. Yu. Danilov

Subjects
local phase center, group delay, phase pattern, hodograph of local phase center, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

The main methods for the determination of the object position using code phase and signal carrier phase measurements are given. An accuracy of pseudorange measurements of both carrier phase and group delay code signal depends on local phase center variations for the signals coming from different directions. The relation of group delay and local phase center of the antenna is determined wherein the key factor is frequency dependence of phase or local phase center variation in solid angle of the radiation pattern. The definition of local phase center whose coordinates depends on the direction of radio signal is given. The single helical antenna analysis of local phase center position is carried out considering that the radio technical performances of the navigation antenna’s spacecraft «Glonass» depends on the same ones of its radiating elements. The features and the technique for hodographs computation of the helical radiator’s navigation phased antenna array using electrodynamic simulation tools are considered. The offset estimation of local phase center is obtained. The features of that offset in relation to the radiator construction depending on the operating frequency are detected.

Published
2022
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2. Accounting for the Structure of a Radio Source in the Processing of Geodetic VLBI Observations

Subjects
структурная задержка, structural delay, radio source delay, внегалактический радиоисточник, ionospheric-free combination of delays, функция Гаусса, карта радиояркости, group delay, extragalactic radio source, Gaussian function, РСДБ, групповая задержка, задержка сигнала от радиоисточника, radio brightness map, VLBI, ионосферно-свободная комбинация задержек
Abstract

Тема выпускной квалификационной работы: «Учет структуры радиоисточника при обработке Ð³ÐµÐ¾Ð´ÐµÐ·Ð¸Ñ‡ÐµÑÐºÐ¸Ñ Ð Ð¡Ð”Ð‘-наблюдений». Данная работа посвящена созданию Ð¿Ñ€Ð¾Ð³Ñ€Ð°Ð¼Ð¼Ð½Ñ‹Ñ ÑÑ€ÐµÐ´ÑÑ‚Ð², Ð¿Ð¾Ð¼Ð¾Ð³Ð°ÑŽÑ‰Ð¸Ñ ÑƒÑ‡Ð¸Ñ‚Ñ‹Ð²Ð°Ñ‚ÑŒ структуру источника при регулярной обработке РСДБ-наблюдений. РСДБ-наблюдения применяются при расчёте параметров вращения Земли (ПВЗ), которые используются в ÑÐ¸ÑÑ‚ÐµÐ¼Ð°Ñ Ð½Ð°Ð²Ð¸Ð³Ð°Ñ†Ð¸Ð¸. В частности, при определении ÐµÐ¶ÐµÑÑƒÑ‚Ð¾Ñ‡Ð½Ñ‹Ñ Ð¿Ð¾Ð¿Ñ€Ð°Ð²Ð¾Ðº к всемирному времени UT1 используется групповая задержка сигнала от Ð²Ð½ÐµÐ³Ð°Ð»Ð°ÐºÑ‚Ð¸Ñ‡ÐµÑÐºÐ¸Ñ Ñ€Ð°Ð´Ð¸Ð¾Ð¸ÑÑ‚Ð¾Ñ‡Ð½Ð¸ÐºÐ¾Ð² между двумя удалёнными радиотелескопами. Групповая задержка является суммой задержек, Ð¾Ð±ÑƒÑÐ»Ð¾Ð²Ð»ÐµÐ½Ð½Ñ‹Ñ Ñ€Ð°Ð·Ð»Ð¸Ñ‡Ð½Ñ‹Ð¼Ð¸ эффектами. Задержка сигнала от радиоисточника, обусловленная его структурой называется структурной задержкой. Существующие программы учёта структурной задержки обладают численной неустойчивостью, поэтому не используются при определении ПВЗ, а так же Ð´Ñ€ÑƒÐ³Ð¸Ñ Ð·Ð°Ð´Ð°Ñ‡, ÑÐ²ÑÐ·Ð°Ð½Ð½Ñ‹Ñ Ñ обработкой Ð´Ð°Ð½Ð½Ñ‹Ñ Ð Ð¡Ð”Ð‘-наблюдений. Передо мной стояла цель создать программу, которую можно было бы использовать для учёта структуры источника.В Ñ Ð¾Ð´Ðµ работы удалось написать ряд программ на языке Python, Ð¾ÑÐ½Ð¾Ð²Ð°Ð½Ð½Ñ‹Ñ Ð½Ð° Ð°Ð»Ð³Ð¾Ñ€Ð¸Ñ‚Ð¼Ð°Ñ , Ð¾Ð¿Ð¸ÑÐ°Ð½Ð½Ñ‹Ñ Ð² статье Патрика Шарло [8], по-разному ÑƒÑ‡Ð¸Ñ‚Ñ‹Ð²Ð°ÑŽÑ‰Ð¸Ñ ÑÑ‚Ñ€ÑƒÐºÑ‚ÑƒÑ€Ñƒ источника, и проведено Ð¸Ñ ÑÑ€Ð°Ð²Ð½ÐµÐ½Ð¸Ðµ., The subject of the graduate qualification work is “Accounting for the Structure of a Radio Source in the Processing of Geodetic VLBI Observations”. This work is devoted to the creation of software tools that help to take into account the structure of the source in the regular processing of VLBI observations. VLBI observations are used to calculate the parameters of the Earth's rotation (ERP), which are used in navigation systems. In particular, the group delay of the signal from extragalactic radio sources between two remote radio telescopes is used to determine the daily corrections to universal time UT1. The group delay is the sum of the delays due to various effects. The signal delay from a radio source due to its structure is called structural delay. The existing programs for taking into account the structural delay have numerical instability, therefore they are not used in determining the PVD, as well as other tasks related to the processing of VLBI observation data. Before me, the goal was to create a program that could be used to take into account the structure of the source.In the course of the work, it was possible to write a number of Python programs based on the algorithms described in the article by Patrick Charlot [8], which study the creation of a source in different ways, and they were compared.

Published
2022
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