Faculty of air transport engineering the department of «air navigation systems»

1.1.2 Airspace planning.
The determination of separation minima and the separation of routes for use by aircraft is an essential element of airspace planning. The main reference document to be used by planners is the Air Space Planning Methodology Guide for Determining Separation Minima (Doc 9689).
In general, separation minima and route separation can be described as a function of three factors: navigation characteristics, aircraft exposure to risk, and available risk mitigation measures. The separation of aircraft and the division of ATS routes are not exactly the same.
Factors affecting the definition of separation and separation of routes:
For example, separation between aircraft is usually applied between two aircraft, and as a result, the traffic density risk component is usually considered to be one pair of aircraft. For the purposes of route separation, this is not the case: traffic density is determined by the volume of air traffic along the divided ATS routes. This means that if all aircraft in a given airspace have the same navigation characteristics, it can be assumed that the separation minima between a single pair of aircraft will be less than the separation required for parallel ATS routes.
The complexity of determining the separation of routes and separation minima is affected by the availability of the ATS surveillance service and the type of communication used. If an ATC surveillance service is available, this means that the risk can be reduced by including a requirement for ATC intervention.
When separation minima and route separation are determined using a conventional sensor-based approach, the navigation performance data used to determine separation minima or route separation depends on the accuracy of the raw data from specific navigation aids, such as VOR, DME, or NDB. In contrast, PBN requires the use of an RNAV system that integrates raw navigation data to determine the location and solve the navigation problem. When determining the minimum separation and separation of routes in the context of the PBN, such integrated "output" of navigation characteristics is used.
To determine the separation minima and route separation, airspace planners make full use of this part of the navigation specification, which prescribes the characteristics required of the RNAV system. To determine the separation of routes and separation minima, airspace planners also use the required characteristics, namely: accuracy, integrity, availability, and continuity.
There are two types of navigation specifications: RNAV and RNP specifications, and that the distinctive feature of RNP specifications is the requirements for on – board monitoring of performance and issuing warnings. For example, the separation minima and route separation obtained from the RNP 1 specification are expected to be less than the values obtained from the RNAV 1 specification, although the scale of this advantage is still subject to further evaluation.
In procedural airspace, separation minima and route separation based on RNP specifications are expected to provide greater advantages over the use of RNAV specifications. This is because the on-board performance monitoring and warning function can compensate to some extent for the lack of an ATS surveillance service, providing an alternative means of reducing risk.