SN User's Guide - ESC Home - NASA

System
Element
Table 10-9. Real-time Operations Activities Overview for FDF and NISN
Functional
Responsibility
FDF Processing of tracking data 1. Receiving and
processing real-time TDMs
from GTs
Generating orbit and
ephemeris data
Activity Description Applicable Timeline
2. Generating and
transmitting real-time state
vectors
NISN Routing data/messages 1. Performing data-driven
configuration and
reconfiguration of the
communications channels
as needed
System
Element
1. During the scheduled
tracking period
2. When the transmitted
state vectors have epoch
time deterioration which
exceed the S-band and Kuband
service required
values
1. During the duration of
customer real-time
operations
Table 10-10. Real-time Operations Activities Overview for GTs
Functional
Responsibility
GTs Providing TDRSS
forward, return,
and tracking
services to
customers
Interfacing a
TDRS with
customer
platform based
upon specified
RF
characteristics
Responding to
NCCDS's
administrative
command and
coordination
Activity Description Applicable Timeline
Prior to the Real-Time Service:
1. Processing the received SHOs
from the NCCDS, including:
a. Performing syntax checking
b. Reserving the required
equipment
1. Any time from 10
minutes to 48 hours before
service start time
2. Performing Pre Service Test 2. Up to three minutes
prior to service start.
3. Processing of the NCCDSsupplied
state vectors
4. Generating the TDRS antenna
pointing angles (i.e., look angles) and
range dynamics data
5. Generating commands to
configure the ground equipment and
the TDRS
6. Acquiring TDRS antenna:
positioning the scheduled TDRS SA
antenna boresight toward the
scheduled customer platform
3. Prior to start of service
4. At about 6 minutes prior
to service start time
5. At about 1-2 minutes
prior to service start time
6. Two to 5 minutes prior
to the service start time in
an SA service SHO
Revision 10 10-27 450-SNUG