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d. Noncoherent Mode. For noncoherent modes, the customer platform
transmitted return link carrier frequency is derived from an on-board local
oscillator. The customer platform transmit frequency for noncoherent service
must be defined by the customer MOC to an accuracy of +6 kHz in its service
specification code when requesting TDRSS KaSA return service. For
customers whose frequency uncertainty is greater than +6 kHz, an expanded
frequency search capability is available.
e. Asynchronous Data Modulation. The data modulation is asynchronous to the
carrier.
8.3.2.2 DG2 Signal Parameters
KaSA DG2 signal parameters are discussed for noncoherent operation only. Tracking
services are not provided via KaSA operations.
a. DG2 Noncoherent. The DG2 carrier is independent of the TDRSS KaSA
forward service carrier frequency. The customer platform transmit frequency for
DG2 noncoherent service must be defined by the customer MOC to an
accuracy of +6 kHz in its service specification code when requesting TDRSS
KaSA return service. For customers whose frequency uncertainty is greater
than +6 kHz, an expanded frequency search capability of +21 kHz is available
after start of the return service.
b. Functional Configurations. Table 8-6 lists the DG2 KaSA return service
functional configurations for 225 MHz return service through the SN ground
terminal receiver and a further description of the functional configurations, the
I-Q channel ambiguity, and data polarity ambiguity is found in Appendix B,
paragraph B.3.3. Refer to paragraph 8.3.6 for the 225 MHz and 650 MHz IF
service functional configurations.
8.3.3 Communications Services
To obtain TDRSS KaSA return service performance defined in this paragraph, the
customer platform transmit signal must meet the requirements found in Table 8-7 and
signal characteristics specified in Table 8-9. The TDRSS KaSA return service
performance defined in this paragraph also assumes return service operation in an
AWGN environment. Appendix G discusses performance degradations to the TDRSS
KaSA return service due to RFI. Example link calculations are provided in Appendix A.
TDRSS KaSAR supports only non-powered flight customer dynamics
(R < 7.9 km/sec, R < 11.4 m/sec 2 , and R < 0.013 m/sec 3 ).
8.3.3.1 Acquisition
The KaSAR service supports acquisition for customer platforms operating under nonpowered
flight dynamics as defined in Table 8-7. The KaSAR service total channel
Tacq will be less than or equal to the sum of the following, which are given in Table 8-7:
a. Autotrack acquisition time (when the TDRSS KaSA return service autotrack
mode is enabled)
Revision 10 8-16 450-SNUG