Commands

Commands typially operate on named objects. Most are affected by the sticky OutputRate keyword. Examples:

# Generate inertial and earth fixed ephemeris using default output rate
Command PrintEphemeris gj_40x40 GCRF gj_40x40_i.e;
Command PrintEphemeris gj_40x40 ITRF gj_40x40_f.e;
# Create Matlab/Octave functions plotting data at 1 minute intervals
OutputRate Minutes 1;
Command PrintRange vinti kep vinti_rng_vk;
Command PrintRTC   vinti kep vinti_rtc_vsp;

OutputRate Duration

Sticky setting specifying the rate at which an output should be generated.

Command PrintEphemeris orbit_name frame output_file_name

Writes STK .e formatted position and velocity ephemeris for the specified satellite name. The output rate is determined internally. The filename suffix is user specified (does not default to .e). Output units are meters and meters/second.

Command PrintOrbit orbit_name frame output_file_name

Command PrintRange orbit1_name orbit2_name output_file_prefix

Command PrintRangeSpectrum orbit1_name orbit2_name output_file_prefix

Writes a Matlab/Octave compatible function to the specified filename with the .m suffix added. When run in Matlab, the function plots the range vs. time over the duration of the scenario. The figure handle and data are returned for use. Output units are specified by DistanceUnits. In addition, the spectrum of the error is plotted where frequency is revs/period w.r.t. orbit1. This functionality is intended for comparing differences between ephemerides of the same orbit definition. For example, to compare the error between SLR based and numerically propagated ephemerides. Or, say, the difference between two analytic propagators.

Command PrintRTC orbit1_name orbit2_name output_file_prefix

Writes a Matlab/Octave compatible function to the specified filename with the .m suffix added. When run in Matlab, the function plots the relative position of the second orbit w.r.t. the first, vs. time over the duration of the scenario. The 3D plot is in the traditional radial, transverse (in-track), cross-track reference frame used for relative orbital dynamics. The figure handle and data are returned for use. Output units are specified by DistanceUnits.

Command TransferOrbit start_orbit end_orbit Xfer_start_time Duration output_file_prefix

Computes a transfer orbit using the shooting method described by Wiesel's "Modern Astrodynamics". The propagator model is defined for the start_orbit is used for the transfer orbit. Functionality is currently limited to an instantaneous delta-v with a transfer time of less than 1/2 rev. However, there are no limitations on the propagator model (there is no 2-body assumption). Summary information about the transfer is written to the header of the Matlab/Octave compatible output file.

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