Downlink Delay

The downlink delay constraint enforces a time gap between data sensing and its downlink.

It simulates the condition where the satellite is required to manoeuvre in order to align its antenna to the ground station.

Two time constants are defined

• Entry: Minimum time delay between end of downlink and start of sensing

• Exit: Minimum time delay between end of sensing and start of downlink.

• Exit per GByte: Minimum time delay between end of sensing and start of downlink as a function of the size of data to be downloaded. It adds to the fixed Exit time to implement a linear function dependent on the data size in GBytes, expected to be different for every swath.

The constraint will act on the visibility opportunities by trimming their duration to comply with the downlink delay. Therefore you need to create a sensing plan first and an antenna visibilities after.

Downlink delay constrain disabled:

Downlink delay constraint active (Exit = 300", Exit per GByte = 40", Swath size = 2.5 GBytes --> exit time = 300 + 40 * 2.5 = 400")