SetState Equi
Set the orbit state of a satellite or missile using equinoctial coordinates
Syntax
SetState <VehObjectPath> Equi {Propagator} {NoProp | {TimeInterval}} <StepSize> {CoordSystem} "<OrbitEpoch>" <SemimajorAxis> <h> <k> <p> <q> <MeanLon> {Retrograde | Posigrade} ["<CoordEpoch>"]
Related commands
Description
The SetState Equi command sets the orbit state of the specified satellite or missile and propagates the orbit over the specified time period. The propagated ephemeris data is spaced by the <StepSize> parameter.
The SetState Equi command is valid for Satellite and Missile only.
| Parameter | Description |
|---|---|
| {Propagator} | This parameter is case sensitive and the Propagator name must match the format used in the Satellite's Orbit page or Missile's Trajectory page under Basic properties. Valid values for Satellite are TwoBody, J2Perturbation, J4Perturbation, HPOP, and LOP. Valid values for Missile are TwoBody and HPOP. |
| {NoProp | {TimeInterval}} | Enter NoProp to set the state of the vehicle but not propagate it. Enter {TimeInterval} to define the beginning and end of the satellite's time period for propagation. For valid {TimeInterval} values, see Time Options. |
| <StepSize> | Enter this in seconds; it must be greater than or equal to 0.001 seconds.
If you select LOP propagator, the <StepSize> must be greater than or equal to one day (86164.09 seconds). |
| {CoordSystem} | Enter any coordinate system supported by the vehicle's central body. All central bodies support Fixed, Inertial, J2000, ICRF, and TrueOfDate. TrueOfEpoch, TEMEOfDate, TEMEOfEpoch, MeanOfDate, MeanOfEpoch, B1950, AlignmentAtEpoch, ITRF2020, ITRF2014, ITRF2008, ITRF2005, and ITRF2000 are supported when the central body is Earth. MeanEarth, PrincipalAxes_440, PrincipalAxes_430, PrincipalAxes_421, etc. are supported when the central body is Moon. |
| "<OrbitEpoch>" | For valid "<OrbitEpoch>" values, see Time Options. |
| <SemiMajorAxis> | Enter this in Connect distance units. |
| <h> | Enter a real number between -1.0 and 1.0. |
| <k> | Enter a real number between -1.0 and 1.0. |
| <p> | Enter a real number between -1.0 and 1.0. |
| <q> | Enter a real number between -1.0 and 1.0. |
| <MeanLon> | Enter this in degrees. |
| {Retrograde | Posigrade} | Enter the orbit direction. |
| ["<CoordEpoch>"] | This parameter is only applicable, and is required, for {CoordSystem} based on an epoch, such as MeanOfEpoch, TrueOfEpoch, TEMEOfEpoch, and AlignmentAtEpoch.
For valid "<CoordEpoch>" values, see Time Options. |
Propagator-specific parameters stored with the vehicle instance aren't affected. For example, when STK receives the SetState Equi command that specifies HPOP for {Propagator}, STK uses the existing HPOP force model data. If you create a vehicle and modify the force model, or load a vehicle with a modified force model, that data isn't modified by this command. If you create a new vehicle using the New command, STK uses the default force model data.
<h> and <k> collectively describe the shape of the vehicle's orbit and the position of perigee, while <p> and <q> collectively describe the orientation of the vehicle's orbital plane.
The STK orbit propagator doesn't completely validate the correctness of the complete orbit state specified. This means that Connect may return a positive acknowledgment even when STK cannot display the orbit track. Connect performs the same validation that occurs from the entry of state data via the user interface.
Examples
To set the path for the ERS1 satellite using equinoctial elements and propagate the orbit:
To set the path for the ERS1 satellite using equinoctial elements and propagate the orbit over the scenario's analysis time period:
Return message
Group membership
This command belongs to the following group(s):
Version
10.1