ACP-WGF 18/IP08
International Civil Aviation Organization
12/05/08
INFORMATION PAPER
AERONAUTICAL COMMUNICATIONS PANEL (ACP)
WORKING GROUP F # 18
Montreal, Canada 12 – 23 May 2008
Agenda Item 3: Development of ICAO position for ITU WRC11
Considerations on spectrum for UAS
(Presented by M.Renard, EADS)
(Prepared by A.Frizon, S.Cormier and M.Renard, EADS)
SUMMARY
This paper presents EADS views with regard to the assessment of radio
spectrum for UAS in the frame of WRC-11 agenda item 1.3.
ACTION
The meeting notes this paper and uses as appropriate for drafting the initial
ICAO position for ITU WRC11.
1.
INTRODUCTION
Unmanned Aerial Vehicles (or UAVs) can fly in segregated air space as well as in non-segregated air
space. When flying in non-segregated air space, they shall do so with the same safety guarantees as
manned aircraft. This is therefore an issue with multiple dimensions, such as legal, regulatory and
certification, which need to be addressed globally therefore not in isolation one from the others.
2.
ISSUE
Spectrum for Control and Communication is essential for the safe operation of UAVs. The provision of
this spectrum is a critical challenge. The ITU World Radiocommunication Conference 2011 (WRC-11)
will address two parts of it under its agenda item 1.3: spectrum for UAV Control and spectrum UAV
ATC Communications relay (for further details, see Resolution 421 adopted by WRC-07).
(3 pages)
-23.
ANALYSIS
Spectrum for UAV ATC communications does not need to be addressed by ITU, as there is an
overwhelming agreement that UAS shall adhere to the same operational practices as conventional manned
aircraft, therefore the same spectrum must be used irrespective of the piloting nature of the aircraft. As a
consequence, the same bands and standards shall be used by both piloted aircraft and UAS.
Focusing now on spectrum for UAV Control and spectrum UAV ATC Communications relay, the
following elements should be kept in mind:

In the utmost majority of UAVs or even all UAVs, there are significant limitations for the size,
weight and power of the airborne data-link equipment -particularly antennas and power
amplifiers-;

A significant number of UAVs can fly in both segregated and non-segregated air space.
Therefore, should specific bands be identified for use to control UAVs, they should be available in each
and every air space, otherwise this will make it impracticable for the utmost majority of UAVs that can
fly in both type of air space. As a consequence, even though the benefit of using aeronautical mobile “en
route” type of allocation is understood when flying in non-segregated airspace, UAVs will require
frequency bands (for their control functions) with both “en route” (CAAs bands) and “off-route” type of
aeronautical mobile allocations (terrestrial as well as space).
If we consider that not all UAS communications links need to operate in the same frequency bands or use
the same technologies, then the conclusion reached in the previous paragraph is not applicable for the
spectrum related to UAV ATC Communications relay. However, as already outlined, onboard UAVs,
there are significant limitations for the size, weight and power of the airborne data-link equipment particularly antennas and power amplifiers, and using different frequency bands may not always be
practicable.
In our view, all that is required is sufficient flexibility in the selection of the frequency band(s) to allow
individual UAVs to operate as designed for in its desired airspace, while offering the appropriate
guarantees in terms of safety. This will clearly require a performance based specification developed
independently of the operating frequencies. We believe that a quality of the transfer of safety related
information can be specified and the corresponding criteria (availability, latency,…) could be reached by
a proven UAV communication system (potentially using different communication links).
Furthermore, the security of the UAV Control and UAV ATC Communications relay links shall be
guarantied, irrespective of the interference environment, the air space, the frequency type, ... The
hereunder approach allow to take into account security protection of these links at different levels, so as to
meet the applicable specifications in non-segregated air space as well as more stringent specifications, as
appropriate, allowing therefore any UAV to fulfill its mission in a safe and secure manner.
-3-
Such an approach will therefore not link the development of UAS with the development of specific
communications technologies, while allowing various communications technologies to be developed and
used in the most appropriate manner.
4.
RECOMMENDATION
We strongly urge ICAO not to make mandatory to use frequency bands with allocation to aeronautical
mobile “en-route” for UAVs control and ATC communications relay functions when flying in nonsegregated air space.
This could seriously put at risk the development of UAS.
The best solution seems clearly to develop a performance based specification independent of the
operating frequencies.