Support for Development of Requirements and Standards for Remotely-Piloted Aircraft Systems

ACP WG-W/4 WP-22

AERONAUTICAL COMMUNICATIONS PANEL (ACP)

Fourth Meeting of the Working Group of the Whole

Montreal, Canada 14 – 16October 2011

Support for Development of Requirements and Standards for
Remotely-Piloted Aircraft Systems (RPAS)

(Presented by the Secretary)

1.Introduction

1.1The Unmanned Aircraft Systems Study Group (UASSG) was established in2007.As this is a multi-disciplinary area of development, it is supported by a number of working groups. One of these working groups is dedicated to telecommunications issues.

1.2The communications working group has identified a number of issues which will require resolution and subsequent standards development. These are given later in the paper.

1.3Before the standardization tasks can be defined, a number of operational requirements need to be defined, relating to how the remotely-piloted aircraft (RPA) and the remote pilot station (RPS) interact. In many cases, these will be influenced by the limits of available and prospective technology. This is especially true in the telecommunications area. In short, the derivation of operational requirements will be a multi-disciplinary exercise in which communications considerations play a large part.

1.4The UASSG membership lacks personnel with aviation telecommunications skills. To remedy this shortcoming, and in the knowledge that the ACP will be tasked with developing the telecommunications standards once the requirements have been established, representatives from the ACP are invited to work with counterparts from the UASSG in identifying and scoping these requirements.

1.5Once the standardization tasks have been defined, the ACP will be tasked with these. This however will not affect the current work programme.

2.Discussion

2.1For RPAS one obvious difference to manned aviation is the fact that the pilot is now physically separated from aircraft, only ‘linked’ via a wireless ‘command and control (C2) data link’.

2.2As with manned aviation, a communication link is required between ATC and the pilot. However this link could potentially bypass the aircraft. It should be mentioned that the UASSG is considering this case as well as the preferredscenario where the RPA is used as a relay for communications between the pilot and ATC.

2.3The C2 link will support the functions related to the traditional ‘aircraft piloting’ (such as steering/positioning of the aircraft, height control, navigation, operation of aircraft systems, monitoring of systems, etc). In many cases, it is also likely that the C2 data link will also ‘carry’ an element of the ATC communications.

2.4Consideration has already been given to various telecommunication scenarios however these need to be developed further.

a. Radio Line-of-Sight Operations

b. Beyond Radio Line-of-Sight Operations (e.g. via satellite links).

c.Use of Third-Party Telecommunications providers.

2.5In the case of RPAS, various scenarios could be overlaid. For example, in a given piece of airspace all manned aircraft may be using radio line-of-sight communications, whereas the RPASmay be using beyond radio line-of-site communications. Provisions regarding such scenarios need to be developed.

2.6We need an agreement on the ‘quality of service’ level that will be required for the C2 link - in particular, the availability requirements and the integrity of the link. Airspace class, density of traffic and type of operation will all affect the minimum requirements for a particular piece of airspace, however standardization will be needed across homogenous airspaces.When a 3rd party comms network provider is utilized, minimum standards for the quality of service will be especially significant. Requirements/procedures for the ‘regulatory oversight’ of these providers will be needed.

2.7Decisions need to be made as to the minimum acceptable level of control interface that will be required between the RPS and the RPA. This could be dictated by the limits of available and prospective telecommunications technology. Possible options include;

a. ‘Stick and throttle’ - remote pilot has full authority over flight;

b. ‘Autopilot’ - remote pilot has ability to select speed, height/altitude, heading; and

c. ‘Flight Management System’ - RPA steered via waypoints.

2.8A “detect and avoid” (D&A) capability is also required. D&A itself may require significant bandwidth and will no doubt place significant demands on the C2 link. The continuous down link of sensor video images is most likely to be unfeasible however, although use of a short range link to support the final approach and taxiing phases of the flight may be required. This again raises the prospect of various telecommunications scenarios which must be considered when developing the operational requirements.

2.9Once the operational requirements have been defined, it will be necessary to identify the standardization tasks that the ACP (and other panels) will be tasked with. These include but are not limited to the following:

a.Standardization of C2 Link protocols? This would be required to enable handover of a remotely-piloted aircraft from one RPS to another; or alternatively, to enable one RPS to be able to control a number of different RPAs.

b.C2 Link encryption?Most likely required to avoid risk of link capture by a 3rd party or to prevent spoofing. How would such encryption keys be controlled if used between a large number of ‘small’ independent operators?

3.Action by the meeting:

The meeting is invited to:

1. nominate a small group to work with the UASSG to identify and scope the operational requirements associated with telecommunications;
2. consult with their respective administrations, if engaged in RPAS activities, to ensure work programmes of the telecommunications and RPAS teams are consistent; and
3. consider the potential standardization tasks resulting from the UASSG work and prepare accordingly.

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