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work for the CCSDS.
It should also be noted that the layered hierarchy does not also imply that the time-ordered
FLOW of operations through the layers is necessarily sequential. For instance, it is perfectly
valid to pre-assemble and pre-number TC Frames, pre-encode them, batch them into CLTUs
and then put the prefabricated CLTUs "on the shelf" for later radiation under control of the
Transfer layer FOP and the Physical layer PLOP. The inter-layer control instructions must
accommodate such non-time-sequential operations. 3 . 5 INTER-AGENCY CROSS-SUPPORT SERVICES
A major feature of the layered CCSDS TC System architecture is its potential for providing a
significantly more comprehensive level of cross support between Agencies than is possible at
present, thus enabling the development of simple and cost-effective interfaces for the wide
range of international space missions which are anticipated in the future. However, the present
CCSDS Recommendations have not addressed the physical implications of cross support.
The CCSDS has established a systems panel to study and recommend the various inter-Agency
cross-support gateways and service access points. The current status of this work may be
found in Reference . Issue 6 Page 3-15 January 1987 CCSDS REPORT CONCERNING TELECOMMAND: SUMMARY OF CONCEPT AND SERVICE ANNEX A
ACRONYMS AND TERMINOLOGY Issue 6 Page A-1 January 1987 CCSDS REPORT CONCERNING TELECOMMAND: SUMMARY OF CONCEPT AND SERVICE ACRONYMS
N(R) : CONSULTATIVE COMMITTEE FOR SPACE DATA SYSTEMS
COMMAND LINK CONTROL WORD
COMMAND LINK TRANSMISSION UNIT
CARRIER MODULATION MODE
COMMAND OPERATION PROCEDURE
FRAME ACCEPTANCE AND REPORTING MECHANISM
FRAME OPERATION PROCEDURE
MULTIPLEXER ACCESS POINT
THE VALUE OF V(R) WHICH IS OBSERVED BY THE FOP IN A
THE SEQUENCE NUMBER ASSIGNED BY THE FOP TO A
PARTICULAR TRANSMITTED TC FRAME
PHYSICAL LINK OPERATIONS PROCEDURE
RF, rf: RADIO FREQUENCY
ST SEQ: START SEQUENCE
THE NEXT EXPECTED TC FRAME SEQUENCE NUMBER; A
COUNTER MAINTAINED BY THE FARM
THE SEQUENCE NUMBER WHICH THE FOP WILL ASSIGN TO THE
NEXT TRANSMITTED TC FRAME Issue 6 Page A-2 January 1987 CCSDS REPORT CONCERNING TELECOMMAND: SUMMARY OF CONCEPT AND SERVICE TERMINOLOGY
Within the Transfer layer, recognition by the receiving end that a TC Frame has passed the
validation and acceptance test criteria as programmed into the Frame Acceptance and Reporting
APPLICATION PROCESS LAYER:
The upper layer of the Telecommand Data Management Service.
In the space data systems layered service architecture, the bottom service of the Telecommand
System. Among its services it delivers the encoded bits of a buffer of transfer frames across
the physical communications link under error-controlled conditions.
Data which are declared to be error free within the error detection and (optional) error
correction capabilities of the...
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- Spring '14