Home' RTCA Documents for Review : DO-343B Contents 7
© RTCA, 2018
Because it is operationally focused, the DO-350/ED-228 establishes the RCP values at
the overall service level. This level is labeled "RCPxxx", where "xxx" is replaced by a
three-digit code specifying the overall duration of the (two-way) operational
communications transaction (see FIGURE 1-4). For the purpose of the current
document, the relevant performance is RCP130, RCP240, RCP400/A1 or RCP400/A2
for data service.
DO-350/ED-228 then performs a first-level partitioning/allocation process of the overall
RCP into four sub-elements: the Air Navigation Service Provider (ANSP), e.g., the FAA
or NATS; the Communications Service Provider; the Aircraft system, e.g., the AES,
CMU, flight management system, displays, etc.; and the aircraft operator, i.e., the pilot
or co-pilot. The specifics of these allocations are shown graphically in FIGURE 1-4.
DO-350/ED-228 has a much higher-level view of the communications transaction than
does the subnetwork-based DO-270. The "Block Diagram View" of FIGURE 1-4 5
provides a block diagram that reconciles the scope of the DO-350/ED-228 with the
scope of earlier DO-270/DO-262 documents.
As shown in the "MASPS
Allocation/Requirement View" of FIGURE 1-4 this current document melds the two
approaches together, by establishing measurable elements of RCP which may be
consistently combined to establish compliance with the overall RCP level.
In terms of the labeled points in FIGURE 1-4, the two-way CSP requirements
correspond to the aggregate transit delay of Point A through Point C, plus Point F
through Point H. The user avionics delays (Point C to Point D, and Point E to Point F)
are accommodated by means of a standard allocation, as discussed in Section 3 of this
document. To facilitate direct measurement of transit delays, this partitioning modifies
the DO-350/ED-228 partition by including the AES’ transit delay as part of the CSP
This document establishes CSP-level requirements by combining delay and continuity
together as joint requirements 6.
1.4.2 Required Surveillance Performance
The concept of Required Surveillance Performance (RSP) is defined in the ICAO
Performance Based Communication and Surveillance Manual (PBCS). As developed
in the PBCS manual, required surveillance performance consists of a collective set of
performance measures established to ensure that the overall communications
transaction is suitable for certain surveillance-related operational goals.
The RSP specifications in support of the ATM operations for the different types of
airspace are provided in DO-350/ED-228. For example, these operational goals may
"achieve synchronisation of trajectories between air and ground in airspace where ATS
surveillance services are provided”. DO-350/ED-228 maps these operational goals to
RSP specifications are also provided in the PBCS manual, but are currently
limited to RSP180/400.
For example, these operational goals may be: "achieve 30 nautical mile lateral and 30
nautical mile along-track separation in procedural airspace." The DO-350/ED-228 maps
these operational goals to CSP-level requirements.
Unlike RCP, RSP is defined in terms of a one-way transaction from the aircraft to the
controller. In terms of FIGURE 1-4, the CSP portion transaction time of this corresponds
to Point F through Point H, with an allocation for the avionics Point E to Point F. As
discussed in RCP above, the partitioned boundary for the CSP for transit delay has
been modified to include the AES so as to create measurable requirements.
For the purpose of the current document, the relevant performance is RSP160, RSP180
or RSP400 for data service supporting surveillance applications.
5 This figure is based on one from the first edition of GOLD.
6 See, for example, requirement D10, et seq. The value of the delay is associated with a probability,
i.e., a probability of achieving that delay. The probability represents the minimum proportion of
communication transactions/surveillance data to be completed /delivered within the specified time.
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