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C.4 Reacquisition
C.4.1 Introduction
C.4.1.1
Once a service has been established, there are a number of conditions or events that
can cause the service to be degraded or to be interrupted, in which case the service
may need to be reestablished. Reacquisition refers to that part of reestablishing service
which includes the following:
a. Reinitiating the customer platform initial acquisition process if it is a forward
service reacquisition; recalculating new settings for the current circumstances
and initializing acquisition circuits if it is a return service.
b. Executing the acquisition events (please see paragraph C.3 above) as indicated
for initial acquisition.
C.4.1.2
Reacquisition may also be required whenever there is a failure to establish service
initially. In some cases of service interruption, additional ground terminal processing
may be needed prior to initiation of the reacquisition process. This may include the
need for the WSC to reconfigure the GCE and/or the TDRS and to calculate and
implement new setup values. These two operations are referred to as TDRSS
hardware reconfiguration and software resetup.
C.4.1.3
The events or conditions that initially trigger the need for a reacquisition may be
categorized as arising from the customer MOC/NCCDS or from the TDRSS as follows:
a. Customer MOC/NCCDS Initiates Reacquisition. This may result indirectly from
a customer MOC request to the NCCDS to reconfigure a service parameter
(resulting in a reconfiguration OPM [Class 03] from the NCCDS to the WSC) or
as a result of the customer MOC/NCCDS directly requesting reacquisition via
an OPM [Class 02].
b. TDRSS Initiates Reacquisition. Conditions that may cause the ground terminal
to initiate reacquisition include a loss of carrier lock, service alarms, and
hardware or software failures. Detailed and precise scenarios in this regard are
beyond the scope of the current discussion. However, some general concepts
are presented in paragraphs C.4.2 and C.4.3 to provide some additional insight
into the reacquisition process.
C.4.1.4
The primary focus here will be on reacquisition initiated by the customer MOC/NCCDS.
Revision 10 C-15 450-SNUG