Honeywell International Inc. 9PGTPL-100A Manuale Utente
Page 11
1 Mar 2006
34-45-54
MAINTENANCE MANUAL
TPL-100A Processor / Part No. 940-0530-001
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(4) Intra-Formation Message/Transmission Characteristics
Intra-formation transmissions comply with the specifications identified in Table 2 (on
average per aircraft):
average per aircraft):
(5) MODE S Data Protection
MILACAS-FR data protection techniques use the existing Mode S error detection and
correction (EDAC) logic combined with data protection keys. The data protection keys
come from strong commercial-grade algorithms.
correction (EDAC) logic combined with data protection keys. The data protection keys
come from strong commercial-grade algorithms.
In pre-flight, each formation aircraft pilot enters a mission-specific pass-phrase into the
mission computer. The mission computer communicates the pass-phrase to the
MILACAS-FR Processor. The processor uses this value and a pre-stored random seed
to generate two mission-specific data protection keys:
mission computer. The mission computer communicates the pass-phrase to the
MILACAS-FR Processor. The processor uses this value and a pre-stored random seed
to generate two mission-specific data protection keys:
•
112-bit data protection key
•
80-bit masking key.
When the flight crew selects the data protection function, each 112-bit data-link
message is protected with the 112-bit key before the computation of the parity field.
The parity computed over the protected message is inserted in the PI field of the data
stream in place of the standard parity. Standard parity is computed over the
unprotected message.
message is protected with the 112-bit key before the computation of the parity field.
The parity computed over the protected message is inserted in the PI field of the data
stream in place of the standard parity. Standard parity is computed over the
unprotected message.
Before transmission, the ME and PI fields of the data stream are protected with the
80-bit masking key. The masking key protects the fields against monitoring by and
disclosure to an unauthorized entity. The DF, AF, and AA fields are not protected so
that the protected data-link message is received and interpreted as a valid DF19 Mode
S extended squitter.
80-bit masking key. The masking key protects the fields against monitoring by and
disclosure to an unauthorized entity. The DF, AF, and AA fields are not protected so
that the protected data-link message is received and interpreted as a valid DF19 Mode
S extended squitter.
Table 2. MILACAS-FR UF19/DF19 Extended Squitter Messages
MESSAGE
SOURCE
RATE
POWER LEVEL
INFORMATION
CONTENT
UF19
MILACAS-FR
(1030-MHz link)
(1030-MHz link)
2 Hz from wing
aircraft
aircraft
1 Hz from lead
aircraft
aircraft
Changes with
different power
programming
(30-52 dBm)
different power
programming
(30-52 dBm)
Mil A/C ID, position
data request for
squitter validation
data request for
squitter validation
DF19
MILACAS-FR
(1090-MHz link)
(1090-MHz link)
2-4 Hz from lead
aircraft
aircraft
Changes with
different power
programming
(30-57 dBm)
different power
programming
(30-57 dBm)
Mil A/C ID, A/C
position data,
formation data,
formation command
and guidance data
position data,
formation data,
formation command
and guidance data