Document number
205065
Version
Rev. N
Issue date
2019-02-04
Sirius OBC and TCM User Manual
Page
163
of
174
Sequence Count
Identifier provided to be able to
track a specific packet.
Packet Length
Specifies number of octets within
the packet data field. The
number shall be number of
octets in packet data field
–
1.
Figure 10.5 Data Field Header
Table 10-4 Data Field Header
Field
Description
Comment
CCSDS Secondary Header
Flag
Shall be set to ‘0’
TC PUS Packet PUS Version
Number
Shall be set to
‘001’
Ack
Specifies level of reporting to
ground by the receiving
Application Process. Currently,
the TCM-S always send
acceptance success/failure
reports and execution completion
success/failure reports
regardless
Service Type
Indicates the service to which the
packet relates
Service Subtype
Indicates the subtype of the
service the packet relates to
Source ID
Not used
Spare
Not used
Application data holds the data elements of the command.
Spare may be used to do padding of TC to achieve an integral number of words.
The checksum of the packet error control field shall be calculated using CRC with
polynomial 0x8408, LSB first, and initial value 0xFFFF over the whole TC Packet except the
two last octets.