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Sat Track GS Calc RF-Link

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RF-LINK

S-band ground dome: sky coverage and link closure for LEO passes

Setup

Link scenario

Can it close the link?

Layer

Coverage outlines Beams (-3 dB) Boresights Hatch gaps 3D antenna models

Pass simulator

Speed

Cross-section through the station, the satellite and the centre of the Earth. Vertical scale is the same as horizontal.

At this position

Track across the sky

Coloured stretches show which ground antenna closes the link. Grey stretches do not close.

Margin over target during the pass

Doppler shift

Distance and elevation

Whole pass, added up

Link chain in one direction

Link margin by elevation

Satellite antenna options

Model notes. Beams are cosine-power patterns matched to the -3 dB beamwidths, with a floor for sidelobes and back radiation. Antennas are switched, one best antenna per direction, with no combining. Polarisation loss is a flat table (0.5 dB circular match, 3 dB circular to linear or linear to linear, 20 dB opposite circular). Rain adds sky noise as well as loss. The two-QHA satellite option includes 3 dB of splitter loss. Nothing models terrain, mounting structure, ground reflections or antenna coupling. Each ground antenna has its own Pluto, PA, diplexer and LNA. Noise is referred to the antenna terminal: antenna temperature (sky and ground weighted by the pattern), feed loss, diplexer, LNA and Pluto noise figure. The satellite is either nadir-pointed or tumbling, and a tumbling satellite is planned at a percentile of random orientations.

Coding gains and required Eb/N0 are for a bit error rate of 1e-5. Atmospheric loss scales the zenith value by air mass.

Antenna stack

Ring count

Ring elevation

°

First azimuth

°

Selected antenna