SN User's Guide - ESC Home - NASA

the initial total channel acquisition, with a probability of at least 0.99. If lock is not
achieved within 10 seconds of loss of lock, an acquisition failure notification message
will be sent to the MOC and the SN ground terminal will reinitiate the initial service
acquisition process. Upon receipt of the loss-of-lock indications in the UPD, the
customer MOC may request a TDRSS KaSA return service reacquisition GCMR (refer
to Section 10). It is recommended that the customer MOC delay initiation of the GCMR
for at least 35 seconds after initial receipt of the loss-of-lock indications in the UPD.
8.3.3.5 Additional Service Restrictions
a. Sun Interference. The TDRSS KaSA return service performance will not be
guaranteed when the center of the sun is within 0.5 degrees of the TDRS KaSA
receiving antenna boresight. Additionally, the TDRSS KaSA return service
performance will not be guaranteed when the center of the sun is within 1
degree of the boresight of the SN ground terminal receiving antenna supporting
the TDRS.
b. Mutual Interference. It is possible for mutual interference to exist between
KaSA customer platforms operating with the same polarization and frequency.
The SN can provide tools to assist customers in interference prediction and
interference mitigation.
8.3.4 Real-Time Configuration Changes
Changes to the operating conditions or configuration of a TDRSS KaSA return service
during a scheduled service support period are initiated by a GCMR from the customer
MOC. The requested changes will be implemented within 35 seconds of receipt of the
GCMR at the SN ground terminal. The MOC will be notified upon initiation of the
requested changes via GCM. Additional information concerning SN ground terminal
response times for GCMRs is provided in Section 10. Table 8-8 lists the KaSA return
service real-time configuration changes and their effects on the return service.
8.3.5 Autotrack/Signal Acquisition Scenarios
The following acquisition scenario identifies only the technical aspects of TDRSS KaSA
return service autotrack (if enabled) and signal acquisition by the SN ground terminal
and does not include operational procedures related to acquisition. Acquisition is
dependent upon the customer providing an ephemeris with a maximum epoch
uncertainty as defined in Table 8-7.
Revision 10 8-28 450-SNUG