a 2003 document whose - Institute for Simulation and Training ...

541
Section 8
Distributed Emission Regeneration family
2) System ID Record: Alternate Mode C. Any application that transmits Mode C shall
always set the Alternate Mode C field to the appropriate value in the Fundamental Data
Record and shall set the Alternate Mode C field in the System ID Record to 1. The
application may also send the actual Mode C encoded altimeter in the Mode C parameter.
3) Fundamental Operational Data Record: System Status: System On/Off. The System
On/Off Status shall be set to 1 if any of the Modes (Parameters 1-6) are set to On.
Otherwise the status shall be set to Off. If the Entity State PDU Appearance Damage
Status value = 3 (Destroyed) for the associated entity and the entity is not canceled at the
time it is destroyed, the System Status/System On/Off field and all Parameter 1-6 Status
fields (Bit 13) for Capable modes shall be set to 1 (Off). This change in status shall be
automatically set within 10 seconds of the simulation determining that the entity could no
longer transmit a reply to an interrogation. For the destroyed case, it is not required that
the Operational Status field be set to System Failed or the Parameter 1-6 Damage or
Malfunction Status fields be set to 1. However, these fields can be set if desired. At least
three periodic updates shall be sent for the IFF/ATC/NAVAIDS PDU following the change
to Off status due to the entity being destroyed. After the three periodic updates are sent,
a simulation may either continue to send periodic updates or cease sending them.
4) Fundamental Operational Data Record: System Status: Capable Parameters 1-6
Any application that transmits an IFF/ATC/NAVAIDS PDU with System Type =1
shall set the Capable Parameters 1-6 to report which modes are capable and not capable of
being transponded by the emitting entity.
5) Fundamental Operational Data Record: Operational Status. This status shall be set
to 1 (System failed) if no Parameter 1-6 or Modifier parameter (Emergency, Squawk
Flash, STI) can be transponded regardless of the System Status/System On/Off field
setting. Otherwise, the status shall be set to 0.
6) Fundamental Operational Data Record: Parameter 1-6 Codes. Codes shall reflect
the present code settings for an entity at the time an IFF/ATC/NAVAIDS PDU is
transmitted and are independent of the present Mode Status settings. Code 0 shall not be
used to indicate off for a mode. However, code zero may be transmitted for a mode if that
is the setting for the transponder. Mode 1, 2, and 3 codes represent octal values that are
set into the appropriate code elements. Each associated parameter is an unsigned integer
that includes both the code and status values. When decoded, the code elements are
converted back to the appropriate octal values. If actual Mode C encoded altitude is being
transmitted, an IFF/ATC/NAVAIDS PDU shall be transmitted once for each 100-foot
change in entity altitude.
7) Fundamental Operational Data Record: Modifier Parameters. When a Modifier
parameter is set to on to report truth data not related to a specific interrogation reported
in an IFF/ATC/NAVIADS PDU, and the condition is transitory, such as the Squawk Flash,
the issuing application shall ensure that an IFF/ATC/NAVAIDS PDU is transmitted with
the parameter set to off when the transitory condition has ended. For Squawk Flash, the
On state shall be for 30 seconds when not responding to a specific interrogation.
8) Fundamental Operational Data Record: Alternate Mode 4. The Alternate Mode 4
values shall be set to 1, 2 or 3 if the entity is capable of transmitting Mode 4 as reflected
in the Capable parameter regardless of whether Actual Mode 4 Pseudo-Crypto is also
included in the Parameter 4.