1. To build the “ideal” A Train constellation we will use
STK - Satellite Tool Kit by AGI
We would like to add the 8 AFSCN Ground Stations that support CloudSat.

2. We want to add Ground Stations for command and control of CloudSat
This diagram shows how ground command and telemetry are handled for CloudSat
As can be seen the AFSCN – Air Force Space Control Network is used.

3. The 8 Ground Stations are:
CloudSat uses eight ground stations located around the world to collect telemetry and upload commands to the satellite.
The 8 Ground Stations are:
CTS
DGS
GTS
HTS
NHS
TCS
TTS
VTS

4. Select
Insert>Facility From Facility Database
Then select
Advanced>Network>
USAF AFSCN

5. The 24 USAF AFSCN Ground Stations are shown below
and then select the “Insert” button
Select the 8 Ground Stations that CloudSat uses:
CTSA
DGSA
GTSA
HTSA
NHSA
TCSA
TTSA
VTSA

6. The 8 Ground Stations are then displayed in yellow on the globe
The 8 Ground Stations are then displayed in yellow on the globe. These Ground Stations are distributed around the world to minimize the amount of information that must be stored by the satellites.

7. We want the Access for CloudSat to the 8 ground stations.

8. Select all the Ground Stations and Select
Compute
Then select the 8 Ground Stations
Next, lets “compute” the Access time from CloudSat to the eight Ground Stations

9. In the 3D view a link between GTSA and CloudSat is shown
In the 3D view a link between GTSA and CloudSat is shown. As the satellites orbit the Earth other Ground Station will be linked as CloudSat moves through its orbit.
Click on the picture to see the scenario.

10. We can also generate a report to show when and how long each Ground Station has access to CloudSat.

11. We can also view the Access time in a graphical view
We can also view the Access time in a graphical view. CloudSat orbits the Earth about 14 times per day.

12. Minutes starting from 18 March 2010 12:00 AM
Max Access Time = 75 min
Min Access Time = 5 min
Ave Access Time = 34 min
StDev Access Time = 25 min
Access
No Access
Minutes starting from 18 March :00 AM
The combined access time for a 1 day scenario can be created using the access data which can be captured as a CSV file.
This type of information can be used to determine the amount of on-orbit storage needed and download data rates required.