STK SATPRO
SatPro provides indepth space tools fordesigning and operating
satellite systems.
It adds the following functionality to STK:
• Additional high fidelity orbit propagators• Multiple attitude enhancements• Satellite-specific engineering tools

Additional orbit propagators

High Precision Orbit Propagator (HPOP).
HPOP uses numerical integration of thedifferential equations of motions to generate
ephemeris. Several different force modeling
effects can be included in the analysis.
• Central body gravity• Solar radiation pressure• Drag / atmospheric density• Coordinated turn• ECI velocity alignment with nadirconstraint, ECI velocity alignment
with Sun constraint• Integrators: RK 4, RKF 7(8), RKV 8(9),Bulirsch Stoer, and Gauss Jackson• Sun alignment with nadir constraint,
Sun alignment with ecliptic normal
constraint, Sun alignment with ECI Z
axis constraint, Sun alignment withoccultation normal constraint, Sunalignment with Z in orbit planeLong-term Orbit Predictor (LOP)• XPOP inertial attitude

LOP provides an accurate prediction of
the motion of a satellite’s orbit over manymonths or years. The LOP propagator uses
the same orbital elements as the Two-Body,
J2, and J4 propagators.

• Yaw to nadir

SP3 Propagator• Fixed time slew, variable time slew

This propagator reads .sp3 files of type ‘a’and ‘c’ and enables use of multiple files insequence. These files are used to provide
precise GPS orbits from the National
Geodetic Survey (NGS).

Targeted attitude segments• Third body gravity• CovarianceAttitude profiles

Additional attitude profiles• Nadir alignment with ECF velocity
constraint, Nadir alignment with orbit
normal constraint, Nadir alignment withSun constraint,• ECF velocity alignment with radialconstraint, ECF velocity alignment withnadir constraint• Inertially fixed• Spinning, spin about nadir,Precessing spin, spin aligned

Used to override the basic attitude profile fora satellite, missile, or launch vehicle and havea selected axis (its Z axis by default) point in
the direction of one or more targets, subject
to applicable access constraints.
Multi-segment attitude profiles
Used to set up complex sequences of varying
attitude profiles over time.
Real time attitude data
With an STK Integration license and live data,
you can create an attitude profile using nearreal time flight data.

Attitude analysis
SatPro provides dynamic attitude modelingand simulation using several tools andcalculation components:
3D Attitude graphics window. Provides
an easy way to visualize the attitude of avehicle and changes in its attitude over time.  
It includes the following visual aids:• Attitude Sphere• Vector-based sensor pointing
Attitude coverage. Used to analyze
coverage in various directions over time,using several attitude-dependent figures ofmerit. Requires a Coverage license.

Attitude Simulator
The Attitude Simulator provides the ability toincorporate the following when generating
attitude trajectories:• Custom torque models (e.g., gravity
gradient, aerodynamic, etc.)• Custom momentum biases• Use of customized control laws (including
static and dynamic feedback, dynamic
compensators, etc.)
The tool numerically integrates an attitudestate (represented by a quaternion) and its
body angular velocity components as well asother optional variables.
Attitude Simulator plugin scripts may supply
these variables and generally perform customcomputations during numerical integration.
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Satellite engineering tools
Generate TLE tool

Generates a two-line element set for theselected satellite using either the trajectory
sampling method or single point method.
B-Plane template tool
The B-Plane template tool is used to create
templates that define the configuration ofB-Planes that can be displayed in the 3D
Graphics window. Elements that can bedisplayed are:
• B-Plane• B vector• T-R axes
• Theta• Asymptote• S Vector• Reference vector
Lifetime tool

Solar Panel tool

Walker Constellation tool

The Lifetime tool estimates the amount oftime a satellite can be expected to remain
in orbit before atmospheric drag and otherperturbations cause it to decay. Calculation
options include:

The Solar Panel tool is used to model theexposure of solar panels over a given timeinterval. The resulting data can be used todetermine the varying availability of electrical
power for operations.

• Drag coefficient

Model Area tool

• Solar radiation pressure coefficient• Area exposed to Sun

The Area tool is used to calculate the area ofa model from a given view direction, over agiven time interval, such as an orbit period. It
can be used to calculate the exposed area of:

The Walker tool is used to easily generatea Walker constellation using the Two Body,
J2, J4, or SGP4 orbit propagators. Walker
constellations are based on a simple design
strategy for distributing the satellites in aconstellation based on the total numberof satellites, the total number of planes
and the phasing between satellites inneighboring planes.

• Mass• Drag calculations• Atmospheric density• Solar panels• Solar flux file

• Radiation• Drag area

• Solar flux sigma level• Advanced options to adjust
computation performance

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