Operation of Unmanned Aircraft Systems Under a Fixed Satellite Service Allocation

1

Seattle, Washington, USA October 2014

Operation of Unmanned Aircraft Systems Using a Fixed Satellite Service Allocation

(Presented by John Nelsen)

1.INTRODUCTION

1.1One of the items under consideration by ICAO ACP WG-F has been use of systems operating under fixed satellite service (FSS) allocations to support unmanned aircraft system (UAS) control and non-payload communications (CNPC) links. At ICAO ACP WG-F/28 in March 2013, a draft ICAO position for agenda item 1.5 of WRC-15 including the associated Resolution 153 (WRC-12) was developed. This draft position was approved by the ICAO Council at its 27 May 2013 meeting.

1.1.1 This working paper is an update to ACP WG-F/29 WP 7 presented at the March 2014 meeting of WG-F in Pattaya, Thailand.

1.2The ITU-R (Report ITU-R M.2171) has determined that 34 MHz and 56 MHz of spectrum would be required for the terrestrial and satellite components respectively of the UAS CNPC. WRC-12 considered that UAS operating beyond line-of-sight (BLOS) could utilize the existing 5030-5091 MHz AMS(R)S allocation, however it must be recognized that no current or near-future satellite systems use that band or are planned to use that band. As a result, that band could not be used to support near-term UAS CNPC BLOS operations.

1.3WRC-15 agenda item 1.5 provides the basis for developing radio regulations for satellites in the fixed satellite service to be used to provide for the BLOS operation of UAS CNPC in non-segregated airspace. Such satellites could be used to address both near and far-term UAS CNPC requirements.

2.discussion

2.1The “resolves” of Resolution 153 associated with WRC-15 Agenda Item 1.5 states, “to consider, based on the results of ITU-R studies referred to in invites ITU-R below, the possible regulatory actions to support the use of FSS frequency bands for the UAS CNPC links, as mentioned in the above considerings, ensuring the safe operation of UAS CNPC links, consistent with recognizing e).”

2.2The ACP WG-F/27, 28 & 29 meeting reports reflect the meeting discussion on that topic. The result was the statement of certain “conditions” which should be met in fulfilling the objectives of this agenda item.

2.3Working Party 5B (WP-5B) as the lead ITU-R group has developed the preliminary related Conference Preparatory (CPM) text based on available studies and includes example regulations. Working Party 4A (WP-4A) has provided support for this work. Studies and regulatory work have been developed in response to the “ICAO Conditions”.

2.4 Existing commercial FSS systems operating in Ku and Ka-band FSS allocations offer immediate access to spectrum to support UAS. Specifically, various segments of the FSS Ku-band (10.95 – 14.5 GHz) and FSS Ka-band (17.30 – 31.0 GHz) are suitable for UAS CNPC links. Furthermore, technical studies by the ITU-R in WP-5B, WP-4B and WP-4A indicate that commercial Ku/Ka band FSS satellites can support UAS control links and meet the desired link availability.

3.ACTion by the meeting

3.1

3.1 It is proposed that the meeting consider the proposals for addressing the ICAO conditions and modify the ICAO position accordingly in support of the agenda item.

3.2The meeting is asked to provide guidance on what material is required from the ITU-R that needs to be reflected in ICAO SARPS.

ANNEX

1.INTRODUCTION

WRC-15 Agenda Item 1.5 is to consider the use of frequency bands allocated to the fixed satellite service (FSS) not subject to Appendices 30, 30A and 30B for control and non-payload communications (CNPC) of unmanned aircraft systems (UAS) in non-segregated airspace in accordance with Resolution153 (WRC-12). The resolves of that Resolution call for studies regarding the regulatory actions to support such an application. This annex addresses consideration of the necessary regulatory requirements for the FSS to support UAS in response to the Civil Aviation Conditions. It benefits from the meeting of ICAO Aeronautical Communications Panel (ACP) Working Group-F (WG-F)/28, March 2013, which set forth conditions which would need to be met for FSS CNPC of UAS in non-segregated airspace. This annex indicates how these conditions can be satisfied, including where appropriate through aviation authority certification of the UAS CNPC service as satisfying ICAO Standards and Recommended Practices (SARPS).

2.Civil Aviation Conditions

The ICAO position on agenda item 1.5 includes a set of conditions which would need to be met by any satellite system supporting UAS CNPC. Demonstration of how those conditions could be met by FSS providers would support a positive outcome for agenda item 1.5. A description of those conditions is provided in the sections below along with a description as to how they would be met by the FSS.

2.1ICAO Condition: The technical and regulatory actions should be limited to the case of UAS using satellites, as studied, and not set a precedent that puts other aeronautical safety services at risk.

Several unique radio regulatory provisions are expected to be developed for the FSS bands where UAS CNPC application would be provided. These would include a footnote allowing use of FSS by UAS aircraft earth stations, describing the characteristics of service necessary to ensure safe operation, and pointing to a Resolution incorporated by reference which provides additional requirements. (Such a Resolution has been developed by the United States of America in a proposal for agenda item 1.5 and is being presented to CITEL PCCII in Mérida City, Yucatán, Mexico, September 9 - October 3, 2014. It is included as an attachment.) The Resolution would include resolves covering, for example, the following:

• Identification of frequency bands in Nos. 5.DN and 5.UP that may be used by GSO FSS networks for CNPC, provided that they meet the t requirements contained in the referenced Resolution ;
• Frequency bands to be used by unmanned aircraft ( UA) and unmanned aircraft control stations (UACS) limited to UAS CNPC links;
• Transmissions in the UAS CNPC link as comprising UAS telecommand and telemetry data, sense and avoid data from the UA to the associated UACS, and relay of voice communication between the air traffic control (ATC) and the UACS;
• Definition of an earth station on board a UAS. By inclusion in the resolves of the Resolution, the definition would be incorporated into the Radio Regulations.

As these provisions would be limited to UAS CNPC and would only become applicable when such an application was provided, they would not serve as a precedent for other aeronautical applications.

2.2ICAO Condition: All frequency bands which carry aeronautical safety communications need to be clearly identified in the Radio Regulations.

In an example footnote the potential bands for use are indicated and a Resolution is referenced. The Resolution contains the associated regulatory provisions for specific frequency bands to enable their use to support UAS CNPC applications. It is understood that such use must be certified by aviation authorities in accordance with ICAO procedures as meeting ICAO SARPS for UAS CNPC operation.

2.3ICAO Condition: That the assignments and use of the relevant frequency bands have to be consistent with 4.10 of the Radio Regulations which recognizes that safety services require special measures to ensure their freedom from harmful interference .

No. 4.10 of the RR provides that special consideration must be given to frequencies being used for safety services. Further, No. 15.28 of the RR relates to harmful interference into such safety services.

“Recognizing the transmissions on distress and safety frequencies and frequencies used for the safety and regularity of flight require absolute international protection and that the elimination of harmful interference to such transmissions is imperative, administrations undertake to act immediately when their attention is drawn to any such harmful interference.”

Further, an example Resolution has been developed which includes a resolve indicating that the freedom from harmful interference to UAS CNPC links is imperative to ensure safe operation and administrations shall act immediately when their attention is drawn to any such harmful interference.

2.4ICAO Condition: Knowledge that any assignment operating in those frequency bands:

- is in conformity with the technical criteria of the Radio Regulations.

- Has been successfully co-ordinated including cases where co-ordination was not completed but the ITU examination of probability of harmful interference resulted in a favourable finding or any caveats placed on that assignment have been addressed and resolved such that the assignment is able to satisfy the requirements to provide BLOS communications for UAS;

- and has been recorded in the International Master Frequency Register.

In practice the coordination agreements between satellite operators spell out any specifics as regards the use of frequencies on a particular satellite network, and impact any satellite/UAS operator agreement. FSS networks or channels which could not meet the necessary performance levels as a consequence of coordination would not be suitable for UAS CNPC communications and would not be certified by requisite aviation authorities for such use.

When the coordination process is completed, the ITU-BR is notified by the administration proposing the new system pursuant to the provisions of Article 11 of the RR. Each notice is examined by the ITU-BR with respect to conformity with the Table of Frequency Allocations and other provisions of the Regulations. The notice is further examined with respect to conformity with the procedures for coordination with other administrations. When the examination by the ITU-BR results in a favorable finding, the frequency assignment is recorded in the Master International Frequency Register (MIFR). If the examination is unfavorable, the ITU-BR immediately informs the notifying administration which may choose to resubmit the notice under RR 11.41. It should be noted that the 11.41 designation is at the frequency group level for those groups that were the subject of the unfavorable finding. It is common for a satellite included in the MIFR under 11.41 to have frequency groups that received favourable findings under examination by the ITU-BR and therefore do not have 11.41 status for that group. If a frequency assignment is recorded in the MIFR under RR 11.41, such an assignment is still required to protect frequency assignments of other networks with which coordination has been successfully completed and entitled to protection from other frequency assignments with which coordination has been successfully completed.

The ITU is conservative in determining coordination requirements under Article 9. In practice, satellites that have not completed coordination may nonetheless be fully capable of providing safe services which are fully compliant with ICAO SARPs applicable in conjunction with providing UAS CNPC services.The FSS operator then has to make sure that the outstanding coordination issues are examined to determine if UAS CNPC operations can take place meeting stipulations in footnotes to the RR and provisions in ITU Resolutions related to CNPC of UAS and operate consistent with ICAO SARPS. This would be done, for example, by determining whether the affected network with which coordination has not been achieved is actually in operation and, if so, what the operational parameters are (e.g. orbital location and filed power levels) to ensure that any resultant impact would be acceptable. Provisions for operation would be incorporated into agreed specifications between FSS and UAS operators and subject to certification for UAS CNPC use by requisite aviation authorities.

A resolves in the referenced Resolution states the CNPC links must conform to all applicable technical provisions of the Radio Regulations.

2.5ICAO Condition: That harmful interference to systems is reported in a transparent manner and addressed in the appropriate time-scale.

Rapid resolution of harmful interference is in the general interest of each satellite operator. Unless harmful interference is of the nature to be reported under Article 15 of the RR there is no day to day reporting mechanism for harmful interference. WP 4A indicates there have been very few reports of harmful interference. However, a regular update on the state of harmful interference could be included in reports to aviation authorities.

The example Resolution includes a resolve that real time interference monitoring and predicting interference risks, and planning solutions for potential interference scenarios, shall be addressed in the specific agreements between FSS operators and UAS operators with guidance from Aviation Authorities.

ICAO SARPS could impose further reporting requirements beyond those in the RR. Such ICAO requirements could be a condition of certification for UAS CNPC use by requisite aviation authorities and incorporated into agreements/contracts between FSS satellite and UAS operators.

2.6ICAO Condition: That realistic worst case conditions, including an appropriate safety margin, can be applied during compatibility studies.

The ITU-R studies conducted have already taken this condition into account. WP-5B in a liaison statement to WP-4B (Document5B/Temp/232) has received advice related to the assessment of performance in relation to the sharing studies that between FSS and fixed service in connection with agenda item 1.5 of WRC-15. Any additional safety margins that might be required could be added as specific line items in the yet to be developed SARPS for Beyond Line-of-Sight (BLOS) UAS CNPC.

2.7ICAO Condition: That any operational considerations for UAS will be handled in ICAO and not in the ITU.

It is expected that ITU and ICAO will carry out their mutual responsibilities in a cooperative manner, just as they have in areas involving the provision of AMS(R)S. It is important that the respective roles of ICAO and the ITU be fully understood to ensure appropriate separation of regulatory needs to be addressed in the RR and operational issues to be addressed by ICAO processes. In this context, ITU will develop the typical conditions for operation of CNPC links, and then, ICAO will develop further operational conditions to ensure safe operation through the development of SARPS.

3.0Control of UAS in Non-Segregated Air Space

How would a satellite operator meeting the conditions above support UAS CNPC operation in non-segregated air space? The specific nature of the service being provided to a user is dependent on the contractual arrangement between the satellite network operator and the UAS user, and the terms of that contract would need to be certified for UAS CNPC use by requisite aviation authorities. The performance specifications encompass availability requirements, redundancy, non-pre-emptive status, etc., and these contracts set forth the technical conditions that ensure the safe operation of the UAS in the non-segregated air space If adequate performance is not available for such a service within an FSS network or on specific FSS frequencies to be certified by the requisite aviation authority, it cannot be provided on those networks/frequencies.

4.0 SUMMARY

The sections above describe how the ICAO conditions could be met by the FSS to support UAS CNPC applications. With proper codification of the actions indicated it is expected that the FSS can support the safe operation of such applications.

ATTACHMENT

AGENDA ITEM 1.5:

EXTRACT FROM A PRELIMINARY PROPOSAL FOR WRC-15

SUBMITTED BY THE UNITED STATES OF AMERICA

TO

CIITEL PCCII XXIV MEETING

Resolution [FSS-UA-CNPC] (WRC-15)

Provision related to Earth stations on board unmanned aircraft which operate with geostationary satellites in the fixed-satellite service for the control and non-payload communications of unmanned aircraft systems in non-segregated airspaces

The World Radiocommunication Conference (Geneva, 2015),

considering

a)that worldwide use of unmanned aircraft systems (UAS) ,which includes the unmanned aircraft (UA) and the unmanned aircraft control station (UACS), is expected to increase significantly in the near future;

b)that UA need to operate seamlessly with piloted aircraft in non-segregated airspace;

c)that the operation of UAS in non-segregated airspace requires reliable control and non-payload communication (CNPC) links, in particular to relay air traffic control communications and for the remote pilot to control the flight;

d)that there is a demand for UAS CNPC links via satellite communication networks for communications beyond the radio horizon while operating in non-segregated airspace as shown in Annex 1;

e)that there is a need to provide internationally harmonized use of spectrum for UAS CNPC links;

f) that the use of fixed satellite service (FSS) frequency assignments by UAS CNPC links should take into account their Article11 notification status;

considering further

a)that there is a need to limit the amount of communication equipment onboard a UA;

b)that, as a dedicated satellite system for UAS CNPC links is not likely to be implemented in the short or medium term, it is necessary to take into account the existing and future satellite systems to accommodate the growth in UAS operations;

c)that there are various technical methods that may be used to increase the reliability of digital communication links, e.g. modulation, coding, redundancy, etc. that can be used to ensure safe operation of UAS in all air space;

d)that UAS CNPC relate to the safe operation of UAS and have certain technical, operational, and regulatory requirements;

e)that the requirements in considering further d) can be specified for UAS use of FSS networks,

noting

a)that Report ITURM.2171 provides information on the vast number of applications for UAS needing access to non-segregated airspaces;

b)that Recommendation 724 (WRC-07) notes that FSS is not, intrinsically, a safety service;

recognizing

a)that appropriate technical and operational provisions can be implemented in the ITU-R to enhance the robustness of the UAS CNPC links;