AER
Return the azimuth, elevation and range between two objects
Syntax
AER <FromObjectPath> <ToObjectPath> [{AccessOptions}]
Related commands
Description
The AER Connect command computes the access and returns a record of date/time, azimuth, elevation and range values for the interval start and end times and for each ephemeris point available. When the access is between two satellites, the <FromObjectPath> controls the ephemeris step.
Any number of the following {AccessOptions} can be included in the command:
| {AccessOptions} | Description |
|---|---|
| TimePeriod {Objects | {TimeInterval} | "<TimeIntervalList>"} | Enter the time period to use as the access interval.
Specify Objects to use the object time periods as access intervals. If no TimePeriod option is entered this option is used. For valid {TimeInterval} values see Time Options. For valid "<TimeIntervalList>" specification see Component Specification. |
| MaxStepSize <Value> | The MaxStepSize limits the amount of time that is allowed to elapse between sampling of the constraint functions during access computations. The 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> | The MinStepSize limits the amount of time that is allowed to elapse between sampling of the constraint functions during access computations. The 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. |
| ClockHost {1 | 2 | Base | Target} | Access reports the transmission/reception times using time values associated with the designated clockhost. A value of 1 or Base specifies the first object as the clock host; a value of 2 or Target specifies the second object as the clock host. |
| Mode {Transpond | Transmit | Receive} | The mode of signal transmission of the designated clock host, used in the apparent relative position computation used by Access. Transmit indicates that the clock host is transmitting; Receive indicates the clock host is receiving the signal. Both indicate that light time delay is considered. The value Transpond turns light time delay off (where distinctions between transmit and receive are no longer necessary). |
| AberrationType {Total | Annual | None} | Sets the model of aberration to be used in access computations. None indicates that aberration is ignored; Annual indicates that only annual aberration is accounted for; Total indicates that the full aberration correction is to be applied. |
| TimeConvergence <Value> | Sets the time tolerance used by the access algorithms for determining the start and stop time of access intervals. The event detection routine declares that an event is found when either the value of the access constraint converges to the desired value to within 8 digits or the time interval in which the event lies is within the time tolerance. <Value> is entered in Connect time units (1.0e-9 seconds <= t <= 1.0 seconds).
EventsBasedOnSamples must be set to Off for this value to have any effect. |
| LightTimeDelayConvergence <Value> | Sets the time tolerance used by the access algorithms for computing the light time delay between objects, when light time delay effects are considered. The light time delay is found whenever a correction to the previous estimate is within the time tolerance. <Value> is entered in Connect time units (1.0e-9 seconds <= t <= 0.1 seconds). |
| EventsBasedOnSamples {On | Off} | Turn EventsBasedOnSamples On to determine access intervals simply based on the samples without doing any extra sub-sampling. |
| 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. |
| 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 to have the fixed sample steps calculated on a specific time boundary. <Value> is entered in Connect time units and is between 0.0 and 86400.0seconds.
When this value is entered Step Size Control will be set to use a fixed step to choose samples. |
Graphics
The graphics options available for this command in previous versions have been deprecated in STK 9. These options will be maintained for backward compatibility only. To set Access graphics options use the Graphics SetAccessGfx command. The deprecated options are:
[{InheritFlag}] [{LineGfxState} {AnimGfxState} {StaticGfxState}]
Examples
To determine azimuth, elevation and range between the ERS1 satellite and the Shuttle:
To calculate AER over the specified time period, also specifying the fixed sample step size, time bound value:
To determine azimuth, elevation and range between the ERS1 satellite and the Shuttle for one hour only:
To calculate the AER over Facility1's Sunlight Interval List:
Return message
Connect returns a message that includes all periods of access at intervals of the ephemeris step size of ERS1 (60 Seconds), as illustrated in the following examples:ACK AER /Application/STK/Scenario/stkDemo/Satellite/ERS1 /Application/STK/Scenario/stkDemo/Satellite/Shuttle 1 Nov 2000 00:15:07.29 265.410510 -27.221 2972.776232 1 Nov 2000 00:16:00.00 259.263923 -26.321 2837.253061 1 Nov 2000 00:17:00.00 251.437016 -25.620 2728.537000 1 Nov 2000 00:18:00.00 242.973800 -25.286 2675.586144 1 Nov 2000 00:19:00.00 234.250786 -25.329 2682.449192 1 Nov 2000 00:20:00.00 225.683365 -25.746 2748.399122 1 Nov 2000 00:21:00.00 217.617828 -26.524 2868.139502 1 Nov 2000 00:21:42.68 212.306527 -27.280 2981.498236 1 Nov 2000 01:01:13.11 80.472564 -27.187 2967.668575 1 Nov 2000 01:02:00.00 84.608940 -25.882 2769.511204 . . . 1 Nov 2000 03:35:00.00 153.408299 -21.192 1921.037487 1 Nov 2000 03:36:00.00 150.875093 -23.029 2292.695348 1 Nov 2000 03:37:00.00 148.756308 -25.170 2657.146439 1 Nov 2000 03:37:52.97 147.050311 -27.208 2970.856176
Group membership
This command belongs to the following group(s):
Version
10