Make flight safe and efficient


Narrow Path is the easy web tool for the definition of the buffer area

What is Narrow Path®

Narrow Path recommends the suitable buffer area width for flight operations, considering the navigation performance of drone, the operational altitude and the environmental conditions.

In this way the drone flight can be conducted safely by the pilot, with respect to the potential presence of low level ground obstacles and the terrain profile, particularly required for BVLOS operations.

Narrow Path web tool verifies during mission planning whether the default protection “buffer value” (1:1 rule) related to a specific route can be reduced.

If the flight mission is eligible for  Narrow Path service, specific recommendations about the flight route are given to the pilot with the possibility to monitor the buffer value in real time during the flight phase.

By means of a simulation platform it is possible to estimate the response of different drones available on the market to differents in-flight solicitations.

Plan a safe and efficient flight

Cope efficiently with the mission goals with respect to safety requirements;

Submit a flight plan with acceptable distances from ground obstacles;

Get warnings about abnormal population density distribution on the ground in the area of operations;

Display the buffer area on the map during the flight and get warnings in case of discrepant values;

Compare the estimated protection buffer area with that recommended by Civil Aviation Authority for VLOS and BVLOS conditions.



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Since the introduction of modern navigation technologies it is possible to determine the position of an aircraft in terms of Latitude and Longitude coordinates.

The progress of the navigation capabilities led the ICAO to introduce the term “Required Navigation Performance Capability” (RNPC) and to publish in 1994 the first edition of Doc 9613, Manual on Required Navigation Performance.

Doc 9613 evolution led to its 4th edition (ICAO, Performance-Based Navigation (PBN)) in which has appeared a new navigation specification intended for helicopters flying at low altitude and speed much lower than jet-propelled aeroplanes.

Learn more about ICAO Framework.

Narrow Path project delivered a feasibility study for the application of the PBN to small UAS flying at Low Level. The study focused on the FTE and NSE to explore the possibility to reduce the protection “buffer value” applied to a specific route. This would allow a small UAS to fly closer to obstacles, as appropriate for operations at Very Low Level airspaces.

Learn more about  Narrow Path Project.

What is a “buffer area”

The desired flight path is affected by three independent sources of error that concurs together to the definition of the horizontal and vertical protection level required to build up the “buffer area” around the flight path, according to ICAO international recommendations (ICAO – Doc 9613).

This area can be defined as the sum the following error contributions:

> Path Definition Error (PDE): the difference between the defined path and the desired path at a given place and time;

> Navigation System Error (NSE): the difference between the true aircraft location and the aircraft location indicated by the navigation system;

> Flight Technical Error (FTE): the difference between the aircraft location indicated by the navigation system and the defined flight path;

The PDE is sufficiently small compared to the other two and it can be generally neglected for manned aviation, however it must be taken into account for drones flight, considering the level of cartographic details requested for some high accuracy positioning missions.

Narrow Path tool calculates the Total System Error, by means of a simulation engine that has been developed for the FTE calculation of different drones available on the market.


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