Defining A Priori States

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You can define the a priori orbit states for the Spacecraft objects being processed in a FreeFlyer Orbit Determination system through the Spacecraft object editor or through FreeFlyer script. You will simply set the initial orbital state on the Orbit page of the Spacecraft object editor, or assign the state in script, as shown below.


Spacecraft Orbit Editor

Spacecraft Orbit Editor


// Set the a priori state in FreeFlyer script

Spacecraft1.X = -558.0;

Spacecraft1.Y = 1389.7;

Spacecraft1.Z = 6911.9;

Spacecraft1.VX =  6.74;

Spacecraft1.VY = -3.11;

Spacecraft1.VZ =  1.15;


To set the state sigma and process noise values for the Spacecraft state, follow the instructions on the Defining Properties to Estimate or Consider page.