# Lernkarten

Roland Schenkel
Karten 101 Karten 12 Lernende English Universität 17.01.2012 / 23.01.2021 Kein Urheberrechtsschutz (CC0)
0 Exakte Antworten 89 Text Antworten 12 Multiple Choice Antworten

Which parameter can, which cannot be determined by SLR?

Orbit Parameters

Orbit Determination of Low Earth Orbits

Ionosphere

Troposphere

Clocks (time transfer)

Which parameter can, which cannot be determined by LLR?

Nutation

Polar Motion

UT1

Length of Day

Which parameter can, which cannot be determined by LLR?

High Frequency Earth Rotation Parameters

Ocean tide Amplitudes

Coordinates and Velocities (ITRF)

Goecenter

Coefficients of Gravity Field

Which parameter can, which cannot be determined by LLR?

Orbit Parameters

Orbit Determination of Low Earth Orbiters

Ionosphere

Troposphere

Clocks (time transfer)

How can the high angular resolution of VLBI be explained?

angular resolution = lambda / D, Here D is the diameter of the telescope. Because the same signal is measured in more than one telescope it’s possible to take the distance between these telescopes as D an not only the real diameter.

Which instruments/sensors are required for a VLBI station?

large telescope, receiver, high-precision frequency standard, recording device

Which are the most important error sources for the VLBI of today?

structure of the radio sources (quasars don’t appear as point sources), antenna structure (deformation, thermal expansion), troposphere (water vapor)

Which relativitic effects have to be considered in VLBI analyses (withhout formulas)?

a)“Clock error” (see formula 2.21): The stronger the gravity field is, the more slowly the clocks are running and moving clocks are running more slowly than clocks at rest // b) Signal goes across a Gravity Field (eg. Earth, Sun) (see formula 2.26): a signal is slowed down when propagating through a gravitational field (only relevant when the signal passes very closely to a gravity body)