Subject: [Tm-rid] input to requirements draft

From: Andrei Gurtov <[email-masked]>
Date: Thu, 23 Apr 2020 14:24:54 +0200

Hej

Please find my input for the requirements draft which was discussed at
the interim meeting.

br Andrei

LiU&LFV

Discussion

This document is largely based on the process of one SDO, ASTM.
Therefore, it is tailored to specific needs and data formats of this
standard. Other organization, for example in EU, do not necessary follow
the same architecture. IETF traditionally operates assuming the source
material for the standardization process is publicly available. However,
ASTM standards require a fee for download. Therefore a double-liaison
program at IETF might need to be activated, providing free access to
ASTM specifications for contributors to IETF documents.

The need for drone ID and operator privacy is an open discussion topic.
For instance, in vehicular domain each car carries a publicly visible
plate number. In some countries, for nominal cost or even for free,
anyone can resolve the identity and contact information of the owner.
Civil commercial aviation and maritime industry  also has a tradition of
broadcasting plane or ship ID, coordinates and even flight plans in
plain text. Community networks such as OpenSky and Flightradar use this
open information through ADS-B to deploy public services of flight
tracking. Many researchers also use these data to perform optimization
of routes and airport operations. Such ID information should be
integrity protected, but not necessarily confidential.

In civil aviation, aircraft identity is broadcasted by a device known as
transponder. It is transmitting a four-digit squawk code, which is
assigned by a traffic controller to and airplane after approving a
flight plan. There are several reserved codes such as 7600 which
indicate radio communication failure. The codes a unique in certain
traffic area and can be re-assigned when entering another control area.
The code is transmitted in plain text by transponder and also used for
collision avoidance by a system known as TCAM. The system could be used
for UAVs as well initially, but the code space is quite limited and
likely to be exhausted soon. The expected number of UAVs far exceeds the
number of civil airplanes in operation.

The ADS-B system is utilized in civil aviation for airplane to broadcast
its ID, coordinates, altitude for other airplanes and ground control
stations. If this system is adopted for drone IDs, it has additional
benefit with backward compatibility with civil aviation infrastructure.
Then, pilots and dispatchers will be able to see UAVs on their control
screens and take those into account. If not, a gateway translation
system between the propose drone ID and civil aviation system should be
implemented.

WiFi and Bluetooth are two wireless technologies currently recommended
by ASTM specifications due to their widespread use and broadcast nature.
However, those have limited range (max 100s of meters) and may not
reliably deliver UAV id at high altitude or distance. Therefore, a study
should be made of alternative technologies from telecom domain (WiMax,
5G) or sensor networks (Sigfox, LORA). Such transmission technologies
can impose additional restrictions on packet sizes and frequency of
transmissions, but could provide better energy efficiency and range. In
civil aviation, CPDLC link is used to transmit command and control
between the pilots and ATC. It could be considered for UAVs as well due
to long range and proven use despite its lack of security [3].

L-band Digital Aeronautical Communications System (LDACS) is being
standardized by ICAO and IETF for use in future civil aviation [1,2]. It
provides secure communication, positioning and control for aircraft
using a dedicated radio band. It should be analyzed as a potential
provider for UAV ids as well. This will bring the benefit of a global
integrated system creating a global airspace use awareness.

[1]  N.Mäurer, C. Schmitt: Towards Successful Realization of the LDACS
Cybersecurity Architecture: An Updated Datalink Security Threat- and
Risk Analysis. Integrated Communications, Navigation and Surveillance
Conference (ICNS), IEEE, Washington, DC, USA, April 2019

[2]  N.Mäurer, T.Gräupl, C.Schmitt: L-band Digital Aeronautical
Communications System (LDACS). IETF Internet Draft, Informational Draft,
Fremont, CA, USA, Version 01, draft-maeurer-raw-ldacs-02, April 2020

[3] A. Gurtov, T. Polishchuk and M. Wernberg, Controller-Pilot Data Link
Communication Security, MDPI Sensors 2018, 18(5), 1636.