PBNTF ECTL-RAISG/2 - WP/05 07/03/2014 ICAO EUR PERFORMANCE BASED NAVIGATION TASK FORCE & EUROCONTROL RAiSG MEETING (ICAO EUR PBN TF & EUROCONTROL RAiSG) SECOND MEETING (Brussels, Belgium, 12-14 March 2014) Agenda Item 22: Discussion on GNSS information distribution STIMULATING DISCUSSIONS ON GNSS INFORMATION DISTRIBUTION (Presented by Eurocontrol) This paper presents the meeting with information on requirements for standards applicable to GNSS NOTAM for discussion and agreement on possible establishment of a new Task Force. 1. Action by the Meeting 1.1. The PBNTF-ECTL-RAISG is invited to: a) take note of the information in this paper b) agree on the setting up of a Task Force made of Navigation and GNSS experts that would collect information as proposed in the paper; c) propose volunteers to the TF. (1 page + 1 attachment) PBNTF_ECTL _RAISG2_WP05 GNSS info distribution.docx
Ref: Joint RAISG PBN TF /2/WP5 2 nd joint RAISG / PBN TF meeting WP 5 Stimulating discussions on GNSS information distribution Submitted by Eurocontrol Summary For several years, the ICAO standards applicable to GNSS NOTAM have been questioned but there has been very little success in agreeing on what these requirements should really be. The topic for instance was discussed at international level with FAA and Canada back in 2007/2008; was exposed and discussed in the context of RAISG meetings (since RATF 7 June 2009) and regularly brought to the attention of the AI Operations group since 2010. This paper proposes a pragmatic approach to try to unlock the situation. Comment is made that until the moment standards are updated (if they ever are), current standards apply. GNSS NOTAM services existing in Europe, including their planned updates (e.g. EGNOS NOTAM service by ESSP and GPS RAIM NOTAM services provided by the DFS or EUROCONTROL based on AUGUR) all aim at meeting current requirements. Recommendation The RAISG and PBN TF members are invited to: - take note of the information contained into this paper - agree on the setting up of a dedicated Task Force made of Navigation and GNSS experts that would collect information as proposed in this paper - propose volunteers to the TF
1. Introduction For several years, the ICAO standards applicable to GNSS NOTAM have been questioned but there has been very little success in agreeing on what these requirements should really be. The topic for instance was discussed at international level with FAA and Canada back in 2007/2008; was exposed and discussed in the context of RAISG meetings (since RATF 7 June 2009) and regularly brought to the attention of the AI Operations group since 2010. Latest inputs to the discussion from AI Operations group in February 2014 (see 2 nd RAISG / PBN TF meeting IP 13) show once more that something should be done to address the issues. This paper proposes a pragmatic approach to try to unlock the situation. Comment is made that until the moment standards are updated (if they ever are), current standards apply. GNSS NOTAM services existing in Europe, including their planned updates (e.g. EGNOS NOTAM service by ESSP and GPS RAIM NOTAM services provided by the DFS or EUROCONTROL based on AUGUR) all aim at meeting current requirements. 2. The proposed approach In fact NOTAM is one way to make information available. There could be other means of communication that could be used to provide such information. For instance, FAA has decided for GPS and WAAS to go for a web-based service in complement to a minimal NOTAM service. However it is commonly agreed that the experience gained by the FAA should be taken as an example rather than as a reference. Choosing the right means of communication (NOTAM or else) is a matter of the nature of information to share and the audience. Indeed other stakeholders than airspace users need to be informed of actual or predicted outages in navigation services (e.g. ATC). What is proposed is (1) for Navigation and GNSS experts to define the operational need (what information should be provided and for what purpose), and (2) for Aeronautical Information experts to decide on the most appropriate ways to distribute the information. Step 1 is proposed to be a task coordinated at RAISG and PBN TF level. Step 2 would be discussed with AI Operations counterparts on the basis of information collected at Step 1. It is understood that conducting this analysis is a prerequisite to formally challenge the Standard at ICAO level. The proposed two-step approach is the following: (step 1) What is the need? Who needs information on GNSS, what information and for what purpose? (mainly NAV experts should respond to this question) (step 2) How to respond to that need? What s the best solution (NOTAM, METAR, AIP, web info, Service Notice, etc) to provide this information? (AI experts should respond to this question) Page 2 of 5
It is proposed to RAISG and PBN TF to set up a dedicated Task Force which would be tasked to address step 1 of the approach. The discussion within this TF should be free of any a priori on the solution(s), which is the competence of AI experts. Page 3 of 5
3. Information proposed to be collected by the Task Force (step 1) This section intends to propose an overview of the information that could be collected by the Task Force. This information would be used as input to step 2. A dedicated workshop involving both NAV and AI experts could be organised in order to ensure mutual understanding. 1. Agree on the scope of the discussion: 1.1 List the GNSS systems to be addressed and their respective expected or declared service level 1.2 List the GNSS-based operations to be looked at, together with the navigation aids (GNSS and non-gnss, if any) which are suitable to support these operations It is proposed to limit the discussion to current GNSS systems and their respective declared level of service. The scope could also be initially limited to GNSS-based PBN operations for the final approach phase of flight. 2. Specify events with impact on GNSS expected or declared service level Events are those factors which impact the capability of GNSS systems to support their expected or declared service level. The impact can be of different magnitudes, ranging from a higher vulnerability while the declared service is still available to a lower service level or a total unavailability. 2.1 List and characterise internal and external events to GNSS systems Events which may have an impact on GNSS-based services can be of two sorts: Internal and External events. External events can also be called threats or feared events. Internal events take place inside the GNSS system(s) (e.g. sub-system failure or unavailability due to maintenance or failure). External events take place outside the GNSS system(s) (e.g. interference, iono). Information about the duration, frequency and likelihood of these events should be collected. 2.2 Clarify the nature of these events This should clarify whether these events are scheduled (like maintenance or interference exercise) or not. In case they are not scheduled, it should be clarified whether they are monitored (in real time) or predictable. The following information is also expected to be collected as part of this task: - Actors having access to information - The means to access the information. - Time considerations (e.g. how long in advance the information is available or how fast an event can be detected, etc ) Page 4 of 5
3. Specify GNSS-based service level degradations 3.1 Identify degraded service levels The different types of service level degradation could be identified (magnitude of the impact, area affected, duration, frequency, likelihood). 3.2 Clarify the nature of these degradations This task intends to clarify whether degradations can be predicted or whether they are unscheduled. The following information is also expected to be collected as part of this task: - Availability of mathematical models for predicting impact at service level, inputs and outputs to the models, information on the performance, accuracy and validity of the prediction models (compared against actual performances). - In case no prediction model exists, information about indicators which may have been identified to forecast service level degradation. These indicators can be linked to an event, combination of events or based on other criteria. - Monitoring schemes at service level (and on criteria for forecast). - Actors involved in service prediction, service forecast and service monitoring should be identified. Accessibility of information collected/built by these actors. - Time considerations (e.g. how long in advance the information is available or how fast degradations can be detected, etc ). 4. Specify impact of service level degradation on operations (as listed in 1.2) According to information collected under point 1.2, information about the impact of service degradation on operations should be collected. Alternative means of navigation may be available to support the operation and consequently a degraded GNSS service level may not necessarily transpose into the unavailability of the operation. The availability of integrity monitoring onboard aircraft will also protect airspace users from misleading information. 5. Discuss the relevance of information collected under point 2 (events), 3 (service level degradations) and 4 (impact on operations) for each of the actors involved in Aviation. Actors to consider could include airspace users, airspace planners, ATC, ANSP, GNSS service provider, etc. This should clarify who this information is useful to and for what purpose. 4. Recommendations The RAISG and PBN TF members are invited to: - take note of the information contained into this paper - agree on the setting up of a dedicated Task Force made of Navigation and GNSS experts that would collect information as proposed in this paper - propose volunteers to the TF Page 5 of 5