Walker (Satellites)
Create a Walker constellation using the object as the seed satellite
Syntax
Walker <SatObjectPath> {WalkerOptions} [{AdditionalOptions}]
Description
Connect can direct STK to construct a constellation of satellites using the Walker method. The only prerequisite is that the seed satellite has propagated ephemeris using the Two Body, J2 Perturbation, J4 Perturbation, or SGP4 propagator.
STK calculates the orbital parameters for all satellites in the constellation based on the orbital parameters of the seed satellite, propagates ephemeris for each satellite, and then displays the appropriate graphics.
The following table describes the {WalkerOptions} parameters.
| {WalkerOptions} | Description |
|---|---|
| Type {Delta | Star | Custom} | Valid values are Delta, Star, and Custom. If this parameter is not entered then Delta is assumed. |
| NumPlanes <NumPlanes> | Required. Specify the number of orbital planes. Valid value is between 1 and 999. |
| TotalNumSats <Value> | Specify the total number of satellites in the constellation. Valid value is between 0 and 999. The number of satellites per plane will be determined as TotalNumSats / NumPlanes. The resulting value must be an integer or the command will fail.
Either TotalNumSats or NumSatsPerPlane is required on the command. Entering 0 for TotalNumSats will clear the Walker constellation. |
| NumSatsPerPlane <Value> | Specify the number of satellites in each orbital plane. Valid value is between 0 and 999. The total number of satellites in the constellation will be determined as NumSatsPerPlane * NumPlanes.
Either TotalNumSats or NumSatsPerPlane is required on the command. Entering 0 for NumSatsPerPlane will clear the Walker constellation. |
| InterPlanePhaseIncrement <Value> | Required if Walker Type is Delta or Star. The <Value> must be, at most, one less than NumPlanes.
The InterPlanePhaseIncrement specifies the advancement of the first satellite in a plane compared to the plane to the west as measured in orbital slots. An orbital slot is defined as 360 deg / total number of satellites). |
| InterPlanePhaseAngle <Value> | Required if Walker Type is Custom. The <Value> is entered in degrees ranging from 0.0 to 360.0. The InterPlanePhaseAngle specifies the advancement of the first satellite in a plane compared to the plane to the west, measured as a true anomaly angle. |
| RAANSpacing <Value> | Required if Walker Type is Custom and RAANSpread is not specified, ignored for Delta or Star configurations. Specify the right ascension of the ascending node increment between planes for Custom constellation configurations. The <Value> is entered in degrees ranging from 0.0 to 360.0. |
| RAANSpread <Value> | Required if Walker Type is Custom and RAANSpacing is not specified. Ignored for Delta or Star configurations.
Specify the right ascension of the ascending node angle difference between planes (the RAANSpacing) using the formula RAANSpread = RAANSpacing * NumPlanes. The <Value> is entered in degrees ranging from 0.0 to 360.0. |
The following table describes the {AdditionalOptions} parameters. These are optional parameters that can be entered on the command line.
| {AdditionalOptions} | Description |
|---|---|
| ColorByPlane {Yes | No} | This value specifies whether satellites within the same plane should display using the same color for markers and labels.
The default value is Yes. |
| ConstellationName <Name> | If entered, a constellation is created and all resulting satellites will be placed in the constellation. |
| SetUniqueNames {Yes | No} | Include this option to have the sub-objects of all resulting satellites created with unique names.
The default value is No. |
If you have a large number of satellites in the Walker constellation, these calculations may take a few minutes.
Deprecated Syntax
The syntax for the Walker command has been updated as of STK 11.1 The syntax used in previous versions will be maintained for backward compatibility only. It is highly recommended that the old syntax, seen below, be replaced with the new.
Walker <SatObjectPath> [{WalkerType}] <NumPlanes> <NumSatsPerPlane> {<InterPlaneSpacing> | <TrueAnomaly>} <RAANSpread> {ColorByPlaneFlag} [{AdditionalOptions}]
Deprecated Walker parameters
InterPlaneTrueAnomalyIncrement replaced by InterPlanePhaseAngle
RAANIncrement replaced by RAANSpread
Examples
To create a Walker constellation with the Walk satellite as the seed satellite, with the constellation consisting of two planes with four satellites in each plane and an interplane spacing of 1:
To create a custom Walker constellation, and place all resulting Satellites in a constellation named MyConst:
To create a Walker Star constellation with the Walk satellite as the seed satellite, and have satellite sub-objects created with unique names:
Return message
Group membership
This command belongs to the following group(s):
Version
11.1