AttCov Access
Compute or clear access calculations for an attitude coverage object and set auto-recompute options
Syntax
AttCov <AttCovObjectPath> Access {ComputeOption} [<Parameters>]
Description
Use the AttCov Access command to compute or clear attitude coverage calculations.
{ComputeOption} can be:
| {ComputeOption} | <Parameters> | Description |
|---|---|---|
| Clear | N/A | Clear access calculations for the specified attitude coverage object. |
| Compute | N/A | Compute accesses between the object and the assigned assets. |
| AutoRecompute | On | STK automatically recomputes accesses every time an object on which the coverage definition depends (such as an asset) is updated. |
| Off | Do not recompute accesses. | |
| SaveMode | Save | Access computations are saved with the attitude coverage object. |
| NoSave | Access computations are not saved with the attitude coverage object. | |
| ComputeOnLoad | Access computations are not saved with the attitude coverage object but are recalculated each time the attitude coverage object is opened in STK. | |
| DataRetention | All | Retains start and stop times for all accesses in virtual memory. |
| Static | As access is computed for each point, STK also computes the static value for each attitude figure of merit. Raw access data is then deleted to minimize memory usage. | |
| AssetsRequired | {AtLeast | Equal} <NumAssets> | Specify the condition on the number of assets covering a grid point that must be satisfied for a valid access. <NumAssets> is greater than or equal to 1. |
| Export | "<FilePath>" | Export all computed accesses to an ASCII text file, with a .cvaa extension. |
| AdvComputeOptions | {AdvOptions} | Turn on or off and set parameters for light time delay and event detection and step size control in access calculations. See following table for details of {AdvOptions}. |
For a more in-depth discussion of access options, refer to the STK Help topic on Advanced Basic properties for Attitude Coverage.
AdvComputeOptions {AdvOptions}
The following table describes the options for event detection and step size control. Any or all options can be included on the command line.
| {AdvOptions} | <Parameters> | Description |
|---|---|---|
| UseLightTimeDelay | {On | Off} | Turn on or off the use of light time delay in access calculations. |
| RegionAccessAccel | {Auto | Off} | If set to Auto then grid point visibility is only considered for intervals when the bounding region is visible. This option can improve performance for many cases where visibility periods are short relative to the analysis interval. |
| EventsBasedOnSamples | {On | Off} | Turn EventsBasedOnSamples On to determine access intervals simply based on the samples without doing any extra sub-sampling. |
| TimeConvergence | <Value> | Set the time tolerance used during event detection. Event times will be determined to within this specified tolerance. <Value> is entered in Connect Time units and must be between 1.0e-9 and 315576000.0 seconds.
EventsBasedOnSamples must be set to Off for this value to have any effect. |
| AbsValueConvergence | <Value> | Set the criterion used for convergence for values near 0. <Value> must be between 1e-30 and 1e30
EventsBasedOnSamples must be set to Off for this value to have any effect. |
| RelValueConvergence | <Value> | An event is said to be detected when a constraint value's relative difference compared to the previous sample is within this tolerance. <Value> must be between 0.0 and 1.0
EventsBasedOnSamples must be set to Off for this value to have any effect. |
| MaxStepSize | <Value> | Sets the maximum sampling step size used in access computations when computing the chain. <Value> is entered in Connect Time units and must be between 1.0e-5 and 315576000.0 seconds.
When this value is entered Step Size Control will be set to use a variable step to choose samples. |
| MinStepSize | <Value> | Sets the minimum sampling step size used in access computations when computing the chain. <Value> is entered in Connect Time units and must be between 1.0e-5 and 315576000.0 seconds.
When this value is entered Step Size Control will be set to use a variable step to choose samples. |
| FixedSampleStep | <Value> | Enter a step size value to control the step size used in Access sampling. <Value> is entered in Connect time units and must be between 1.0e-5 and 315576000.0 seconds.
When this value is entered Step Size Control will be set to use a fixed step to choose samples. |
| FixedStepTimeBound | <Value> | Enter a value control the alignment of samples with a UTC time grid. <Value> is entered in Connect time units and must be between 0.0 and 86400.0 seconds.
When this value is entered Step Size Control will be set to use a fixed step to choose samples. |
Examples
To clear accesses for the AttCov object:
To set the Step Size Control to variable with the specified min and max values:
Return message
Group membership
This command belongs to the following group(s):
Version
8.1