scope:

In order to fulfil the previously described purpose, JARUS guidelines on Specific Operations Risk Assessment (SORA) [RD.5] and its Annex E [RD.6] will be analysed together with Acceptable Means of Compliance elaborated by EASA [RD.4]. In case a new version of SORA is released or new regulation regarding UAS and U-Space is issued, this document should be revised.

The main activities that are envisioned in order to complete these guidelines are:

• Analyse the context of these guidelines, mainly in terms of:

o Applicable and ongoing regulation

o Relevant stakeholders

o Relationships among stakeholders

• Identify gaps that need to be discussed and make explicit all assumptions that need to be made in order to provide such guidelines.

• Analyse SORA methodology, focusing on the Operational Safety Objectives role and, more specifically, analyse in detail SORA's OSO#13 External services supporting UAS operations are adequate to the operation, providing an insight of each of the steps that the operator will need to perform to fulfil the criteria for Low Robustness (i.e., for both Integrity and Assurance) for the GNSS external service in Low Risk Operations.

• Produce specific guidelines for UAS operators to comply with the appropriate OSO#13 robustness criteria for GNSS based on the previous analysis but in a usable and straightforward manner.

• Provide the UAS operator with recommendations about mechanism to detect potential GNSS Service Performance degradation as well as actions that could be adopted to mitigate it.

NOTE: Through this document, the term "integrity" may refer to two different concept. The concept of integrity in SORA OSO (safety gain) and the concept of integrity in GNSS (measure of the trust which can be placed in the correctness of the information supplied by the GNSS). In case it is not clear by the context to which meaning the text is referring, they will be referred as 'safety integrity' and 'GNSS integrity' respectively.

PURPOSE

As stated in the Terms of Reference for this Guidance Document, the SORA Work plan performed by WG-105 concluded that an action had to be initiated to improve the capability of external services, as one means to support safe operation of UAS in the Specific Category. Considering that the GNSS receiver is the primary navigation sensor for most mass-produced/commercial UAS, the level of performance of GNSS services, and especially multi-GNSS, has a direct relation with flight safety for UAS, both in nominal and non-nominal conditions according to the particular operational context where it is used.

The term 'multi-GNSS' is used since there are several GNSS constellations that could be used to provide positioning information to UAS. This document addresses, in more detail, some specific constellations/systems/signals due to legacy reasons, global coverage and general public accessibility.

To facilitate fulfilment of 'Operational Safety Objective #13 External services supporting UAS operations are adequate to the operation' from the SORA methodology developed by JARUS and the Acceptable Means of Compliance elaborated by EASA [RD.4] for fulfilment of applicable regulatory framework in Europe for UAS operations in the Specific category identified in [RD.1] and [RD.2], it is necessary to develop guidance material to be used by the UAS operators, manufacturers and integrators (especially SMEs). This action is proposed to be developed under a subgroup of WG-105, namely subgroup 6 SORA, with the cooperation of EUSPA and EASA to validate the guidance material.

This first version of the guidelines is intended for operations in Low Risk (SAIL I and II) in the Specific Category. Further versions of this document will deal with Medium and High Risk in the same category.

The resulting standards will support UAS operators in achieving approval for specific operations in regard to the inherent safety risks associated with the use of GNSS services in UAS operations.