2.14 Performance-Based Communication and Surveillance (PBCS) Concept. The PBCS concept provides objective operational criteria to evaluate different and emerging communication and surveillance technologies and is intended for evolving Air Traffic System Management (ATM) operations. Once these criteria have been set and accepted, a specific implementation of an ATM operation including its technical and human performance may have its viability assessed against these operational criteria.
ATS system changes based on communication and/or surveillance performance align with the PCBS concept (refer to ICAO Doc 9869).
2.14.1 Aligned with Performance-Based Navigation (PBN). The PBCS concept is aligned with the concept of PBN. While the PBN concept applies RNP and RNAV specifications to the navigation element, the PBCS concept applies required communication performance (RCP) and required surveillance performance (RSP) specifications to communication and surveillance elements, respectively. Each RCP/RSP specification includes allocated criteria among the components of the communication and surveillance systems involved.
2.14.2 Communication, Navigation, and Surveillance (CNS)/ATM Model. Where beneficial, RCP, RNP/RNAV, and RSP specifications are applied to communication, navigation, and surveillance elements to ensure the operational system and its components perform in accordance with the specifications. Figure 2-6, Performance-Based CNS/ATM Model, provides an overview of the performance-based CNS/ATM model, which characterizes the relationship of the performance-based specifications among CNS elements supporting an ATM operation.
Note: Similar to the PBN concept, security is beyond the scope of the PBCS concept. However, in some cases, the RCP and RSP specifications may include criteria to support mitigations from security threats.
Figure 2-6. Performance-Based CNS/ATM Model
2-17
2.14.3 PBCS and PBN Differences. There are some differences between the PBCS concept and PBN concept:
1. The PBCS concept applies RCP and RSP specifications, which allocate criteria to ATS provision, including communication services, aircraft capability, and the aircraft operator. The PBN concept applies RNP/RNAV specifications which allocate criteria only to the aircraft capability and the aircraft operator; and
2. The PBCS concept includes post-implementation monitoring programs, on a local and regional basis, with global exchange of information. The PBN concept includes real-time monitoring and alerting functionality in the aircraft capability.
Note: PBCS includes real-time alerts (e.g., when a communication transaction expires or a position report is overdue) that are conceptually different than the PBN alerts (e.g., RNP UNABLE).
2.15 RCP and RSP Specifications Supporting ATM Operations. To perform ATM operations within a performance-based airspace, the standards specify functional, safety and performance criteria for the applicable CNS elements. RCP and RSP specifications, in conjunction with RNP/RNAV specifications, provide these criteria and are intended to facilitate the development of standards for ATM operations. This approach is essential to the evolution of operational concepts that use emerging technologies. For example, within the organized track system (OTS) in North Atlantic High Level Airspace (NAT HLA), the Reduced Lateral Separation Minima (RLatSM) include the following requirements:
• RNP 4;
• CPDLC with RCP 240; and
• ADS-C with RSP 180.
2.15.1 RCP Specifications. An RCP specification represents operational parameters for the complete communication transaction. It is identified by a designator (e.g., RCP 240 or RCP 400) in order to simplify the designator naming convention and to make the RCP Expiration Time (ET) readily apparent to airspace planners, aircraft manufacturers, and operators. The designator represents the value for the communication ET after which the initiator is required to revert to an alternative procedure. The RCP specifications are applied to achieve the performance required of the communication process and may support aircraft separation minima.
2.15.2 RCP Parameters. The following describes the RCP parameters:
1. RCP Transaction Time. An RCP parameter that specifies the maximum time for the completion of a proportion of operational communication transactions after which the initiator should revert to an alternative procedure. Two values are specified:
2-18
• RCP Transaction Time (TT). The maximum nominal time within which 95 percent of operational communication transactions is required to be completed; and
• RCP (ET). The maximum time for the completion of the operational communication transaction, after which the initiator is required to revert to an alternative procedure.
2. RCP Continuity (RCP C). The minimum proportion of operational communication transactions to be completed within the specified RCP transaction time, given the service was available at the start of the transaction.
3. RCP Availability (RCP A). The required probability that an operational communication transaction can be initiated.
4. RCP Integrity (RCP I). The required probability that an operational communication transaction is completed with no undetected errors.
Note: While RCP I is defined in terms of the “goodness” of the communications capability, it is specified in terms of likelihood of occurrence of malfunction on a per flight hour basis (e.g., 10-5), consistent with RNAV/RNP specifications.
Figure 2-7. Actual Communications Performance (ACP)
2-19
2.15.3 RCP Framework and Actual Communication Performance (ACP). In Figure 2-7, Actual Communications Performance (ACP), the combined uplink and downlink performance of ground systems, communication service, and aircraft systems is the Actual Communication Technical Performance (ACTP). Pilots and controllers should respond as soon as possible as part of the overall human performance. Human performance combined with ACT results in ACP. ACP is an indicator of the operational performance of a communication system which includes the human and technical components. Human performance considers such factors as training, procedures, and human-machine interface (HMI). Technical performance comprises the installed elements of communication performance operating together to meet the intended function. ACP is assessed in the same terms and parameters as an RCP specification, its allocations, and other relevant operational criteria provided by an RCP specification. Operationally, an appropriate level of communication performance is required for aircraft systems, communications networks, and ground systems.
Note: In ICAO documentation, pilot response time is called Pilot Operational Response Time (PORT).
Figure 2-8. RCP 240 Illustration RCP 240
99.9% ≤ 240 sec / 95% ≤ 210 sec Pilot Required Communication Controller Technical Performance RCTP RCTP = 99.9% ≤ 150 sec / 95% ≤ 120 sec RCMP = 99.9% ≤ 210sec / 95% ≤ 180 sec Human Performance Technical Performance Human Performance (in seconds) (in seconds (in seconds)
99.9% 60 15 120 15 30 1=240 95% 60 10 100 10 30 • =210 Flight Crew Aircraft Network ATSU System Controller Systems 2-20
2.15.4 RCP 240 Illustration. As illustrated in Figure 2-8, RCP 240 Illustration, the controller sends a data link communication message through the ATSU via the CSP to the aircraft.
The Required Communication Technical Performance (RCTP) is the overall time for the communication to travel from the ATSU to the flight deck and return excluding human response time. RCTP should be less than or equal to 150 seconds for 99.9 percent of the operational time (ET) and must be less than or equal to 120 seconds for 95 percent of the nominal time (TT). The message arrives at the flight deck and the pilot should respond as soon as possible (i.e., ROGER (DM3)/WILCO (DM0), UNABLE (DM1), or STANDBY (DM2)). The pilot responds to the message and it travels back to the ATSU.
2.15.5 RCP 240 Specification Tables. Table 2-4, RCP 240 Transaction Time and Continuity Allocations–CPDLC, shows Transaction Time and Continuity allocations from the sender (controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system. Table 2-5, RCP 240 Availability Criteria (Aircraft System), provides the aircraft system availability criteria. Table 2-6, RCP 240 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
Table 2-4. RCP 240 Transaction Time and Continuity Allocations—CPDLC ACP Controller ATSU system Network Aircraft system Pilot Response Aircraft system Network ATSU system Controller
99.9% (ET) PC/ATSU (30) PATSU(15) PNET(120) PAIR(15) 60 PAIR(15) PNET(120) PATSU(15) PC/ATSU (30) 95% (TT) PC/ATSU (30) PATSU(10) PNET(100) PAIR(10) 60 PAIR(10) PNET(100) PATSU(10) PC/ATSU (30) Table 2-5. RCP 240 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-6. RCP 240 Integrity Criteria (Aircraft System) Integrity Parameter Integrity Value Compliance Means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
2-21
Figure 2-9. RCP 400 Illustration
2.15.6 RCP 400 Illustration. As illustrated in Figure 2-9, RCP 400 Illustration, the controller sends a data link communication message through the ATSU through the CSP to the aircraft. The RCTP is the overall time for the communication to travel from the ATSU to the flight deck and return excluding human factors. RCTP should be less than or equal to 310 seconds for 99.9 percent of the operational time (ET) and must be less than or equal to 260 seconds for 95 percent of the nominal time (TT). The message arrives at the flight deck and the pilots should respond as soon as possible (i.e., ROGER (DM3)/WILCO (DM0), UNABLE (DM1), or STANDBY (DM2)). The pilot responds to the message and it travels back to the ATSU.
2.15.7 RCP 400 Specification Tables. Table 2-7, RCP 400 Transaction Time and Continuity Allocations—CPDLC, shows Transaction Time and Continuity allocations from the sender (controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system. Table 2-8, RCP 400 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
Table 2-9, RCP 400 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
2-22
Table 2-7. RCP 400 Transaction Time and Continuity Allocations—CPDLC ACP Controller ATSU system Network Aircraft system Pilot Response Aircraft system Network ATSU system Controller
99.9% (ET) PC/ATSU (30) PATSU(15) PNET(280) PAIR(15) 60 PAIR(15) PNET(280) PATSU(15) PC/ATSU (30) 95% (TT) PC/ATSU (30) PATSU(10) PNET(240) PAIR(10) 60 PAIR(10) PNET(240) PATSU(10) PC/ATSU (30) Table 2-8. RCP 400 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-9. RCP 400 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
2.16 Required Surveillance Performance (RSP).
2.16.1 Background. In the past, surveillance over oceanic and remote continental areas was limited to pilot position reports via HF radio. When crossing a compulsory reporting point, the pilot would contact the ATSU via a radio operator and report: identification, position, time, altitude, next PR point, name of succeeding reporting point, and remarks.
Once the aircraft entered a radar environment, pilot reports were eliminated. Today, along with voice pilot position reports, surveillance in oceanic and remote continental airspace is accomplished much more accurately through the use of ADS-C. As with CPDLC, ADS-C requires certain performance requirements for operational surveillance in support of specific ATM functions. This includes the transmission of aircraft position, velocity and intent with a specified precision, accuracy and update rates. In combination with RCP and RNP, RSP enables the efficient use of airspace by allowing reduced lateral and along-track separation of aircraft by supplying accurate and frequent updates of aircraft position.
2.16.2 RSP Concept. The concept of RSP relates to the surveillance component and complements RNP and RCP. A collective set of performance measures are established to ensure overall communication transactions and surveillance data deliveries are suitable for certain surveillance related goals. For example, the surveillance goal may be to achieve 30 nautical miles (NM) lateral and 30 NM along-track separation in oceanic 2-23
airspace. RSP is operationally derived and not based on any specific techniques, aircraft technologies, or architecture.
2.16.3 RSP Specification. An RSP specification is identified by a designator (e.g., RSP 180) in order to simplify the designator naming convention and to make the RSP Data Operational Overdue Time (OT) readily apparent to airspace planners, aircraft manufacturers and operators. The designator represents the value for the surveillance data delivery time when the surveillance data delivery is considered overdue.
RSP specifications are applied to airspace based on specific objectives (e.g., the performance required of the surveillance process used to support particular separation minima). The RSP specification is a set of requirements/operational parameters for ATS provision and associated ground equipment, aircraft capability, and operations needed to support performance-based surveillance. Surveillance performance requirements are included and allocated to system components (Required Surveillance Technical Performance (RSTP)). It includes surveillance data delivery time, continuity, availability, integrity, and safety. A specified RSP specification is intended to define the surveillance performance required of a surveillance process to support a particular ATM function.
RSP specification is applied to the airspace, route, or procedure based on the most stringent RSP specification of the required ATM functions.
2.16.4 RSP Parameters. RSP include the accuracy of the reported position, the latency in reporting the position to the controller, and the integrity, availability, and continuity of the surveillance data. The following describes the RSP parameters:
1. RSP Surveillance Data Transit Time. The maximum time for the reception of the surveillance data after which the controller should revert to an alternative procedure.
2. RSP Continuity. The minimum proportion of surveillance data delivery to be completed within the specified RSP surveillance data delivery time, given the service was available at the start of the delivery.
3. RSP Availability. The required probability that surveillance data can be provided.
4. RSP Integrity. The required probability that surveillance data delivery is completed with no undetected errors.
2-24
Figure 2-10. RSP 180 Illustration
2.16.5 RSP 180 Illustration. In Figure 2-10, RSP 180 Illustration, the ATSU establishes an event contract with the aircraft with specific allocations described below:
1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required to respond within 5 seconds or less 99.9 percent of the operational time (OT) and less than or equal to 3 seconds 95 percent of the nominal delivery time (DT).
2. From 2 to 3 (CSP). The signal is then transmitted through the communication service provider (CSP) network. This action must occur within 170 seconds or less for 99.9 percent of the OT and less than or equal to 84 seconds 95 percent of the DT.
3. From 3 to 4 (ATSU). From the (CSP) this message is sent through the ATSU which has a required performance of less than or equal to 5 seconds for
99.9 percent of the time and less than or equal to 3 seconds for 95 percent of the time. The total communication from the event to the controller must be less than or equal to 180 seconds with 99.9 percent probability (OT) and less than or equal to 90 seconds with 95 percent probability (DT).
2.16.6 RSP 180 Specification Tables. Table 2-10, RSP 180 Surveillance Data Delivery and Continuity Allocations—ADS-C, shows allocations for Required Surveillance Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP) consisting of the aircraft system, network and ATSU. Table 2-11, RSP 180 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
2-25
Table 2-12, RSP 180 Integrity Criteria (Aircraft System) provides the integrity criteria for the aircraft system.
Table 2-10. RSP 180 Surveillance Data Delivery and Continuity Allocations—ADS-C RSMP/RSTP Aircraft system Network ATSU
99.9% (OT) 5 170 5 95% (DT) 3 84 3 Table 2-11. RSP 180 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-12. RSP 180 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
2-26
Figure 2-11. RSP 400 Performance
2.16.7 RSP 400 Illustration. In Figure 2-11, RSP 400 Performance, the ATSU establishes an event contract with the aircraft with specific allocations described below.
1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required to respond within 30 seconds or less 99.9 percent of the OT and less than or equal to 15 seconds 95 percent of the DT.
2. From 2 to 3 (CSP). The signal is then transmitted through the CSP network.
This action must occur within 340 seconds or less for 99.9 percent of the OT and less than or equal to 270 seconds 95 percent of the DT.
3. From 3 to 4 (ATSU). From the CSP this message is sent through the ATSU which has a required performance of less than or equal to 30 seconds for
99.9 percent of the time and less than or equal to 15 seconds for 95 percent of the time. The total communication from the event to the controller must be less than or equal to 400 seconds with 99.9 percent probability (OT) and less than or equal to 300 seconds with 95 percent probability (DT).
2.16.8 RSP 400 Specification Tables. Table 2-13, RSP 400 Surveillance Data Delivery and Continuity Allocations—ADS-C, shows allocations for Required Surveillance Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP) consisting of the aircraft system, network and ATSU. Table 2-14, RSP 400 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
Table 2-15, RSP 400 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
2-27
Table 2-13. RSP 400 Surveillance Data Delivery and Continuity Allocations—ADS-C RSMP/RSTP Aircraft system Network ATSU
99.9% (OT) 30 340 30 95% (DT) 15 270 15 Table 2-14. RSP 400 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-15. RSP 400 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration. The aircraft end system shall be capable of detecting errors that would result in corruption, introduced by the communication service.
2.17 High Frequency Data Link (HFDL). Over the past few decades HF has provided an effective means of voice communication over long distance in oceanic and remote continental airspace. HF communication is no longer restricted to voice and provides another means of sending and receiving digital communication. HFDL augments existing VHF and satellite communications (SATCOM) (i.e., CPDLC and ADS-C) data link communication systems. A subnetwork of 15 HFDL ground stations extends worldwide communication coverage beyond that of VHF data link communication subnetworks.
2.17.1 HFDL Applications. HFDL subnetwork provides communication to both ATSU and AOC in oceanic and remote continental airspace and can be used for:
1. Non-SATCOM equipped aircraft with a long-range, cost-effective data link communication capability,
2. Data link communication in polar regions where geostationary satellite connections may not exist or be degraded, and
3. A back-up means of data link communication for SATCOM (CPDLC and ADS-C) equipped aircraft.
2-28