Home' RTCA Documents for Review : ACAS X MOPS DRAFT Vol. 2 Contents DRAFT
TRMINTRUDERSTATE, one for each individual intruder. The associated ONLINECOSTSTATE in-
formation is also specific to an individual intruder. To ensure separation of online cost settings for
each intruder, the state for each online cost is initialized and stored separately by ONLIN EC OST-
STATE for each TRMINTRUDERSTATE.
The previous global advisory of the TRMOWNSTATE is represented by st_own.a_prev. The actions
and rates pertaining to the global advisory issued at the previous time step include: action, dz_min,
dz_max, and ddz. An additional variable pertaining to the global advisory, multithreat, is a boolean
that tracks whether the previous issued advisory was due to multiple intruders. These variables
are all stored in st_own.a_prev. Additionally, the state variable dz_ave_prev is used to persist the
vertical rates for a Maintain advisory.
The display logic values pertaining to the global advisory issued at the previous time step are:
action_prev, word_prev, turn_off_aurals_prev, crossing_prev, and ra_suppressed_prev, which are
stored in st_own. They are used and set in DISPLAYLOGICDETERMINATION.
Several TRMOWNSTATE variables are needed for setting fields in the TRMRABROADCAST-
DATA and TRMGROUNDMSGDATA outputs. st_own.ra_broadcast_prev is a copy of the TRM-
RABROADCASTDATA output from the previous cycle. Information about the most recent threat
for the TRMGROUNDMSGDATA output is stored in st_own.tid_latest, st_own.tti_latest, and st_-
The individual intruder action and corresponding rates from the previous time step are also needed
for use within the per-intruder processing blocks. The previous advisory of the TRMINTRUDER-
STATE is represented by st_intruder.a_prev. The state variables pertaining to individual intruder
advisories include: action, dz_min, dz_max, and sense_prev, which are stored in st_intruder.a_prev.
The intruder advisory state variable st_intruder.a_prev.ra_prev records whether the previous action
was a resolution advisory (RA). The intruder advisory belief state variable b_prev stores the vertical
probabilities, b_prev.w_vert_prev, along with a flag, b_prev.need_init, indicating whether the proba-
bilities were stored on the previous cycle. State is also maintained for coordination with the intruder
and for the type TRM processing performed for the intruder. State variables related to coordination
include: vrc_prev, cvc_prev, and equipage_prev. The intruder state variables address, is_icao, and
coordination_msg_prev are stored input values used for setting fields in TRMCOORDINATIONIN-
TERROGATIONDATA for dropped intruders. The st_intruder.ra_found state variable is used for set-
ting the id of the most recent threat, TID, in TRMGROUNDMSGDATA. The intruder state variable
st_intruder.time_since_ta stores the traffic advisory timer for this intruder. State variables related to
the processing state for the intruder are: protection_mode_prev, protection_mode_curr, processing,
and status, which are stored in st_intruder.
The intruder state variable id is the target identifier supplied by the STM. It is used to associate the
TRMINTRUDERINPUT structure for an individual intruder with the appropriate intruder state.
All of the rates are set to N aN at initialization. Also at initialization, the actions are set to 0 and
st_own.a_prev.multithreat is set to FALSE. After each cycle, the state variables associated with
the global advisory, st_own.a_prev, are set to action, dz_min, dz_max, and multithreat as output
by the ACTIONSELECTION component. The individual action and rate variables, st_intruder.a_-
prev, are set from the act_indiv, dz_min_indiv, dz_max_indiv, and sense_indiv, values within the
Some of the state values are used for maintaining intermediate information for cost estimation
and action selection. For T R M INTRUDERSTATE, st_cost_on and st_arbitrate maintain state in-
formation that is associated with the individual intruder state. st_int.st_arbitrate stores context-
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ACAS Xa/Xo MOPS, Vol. II
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