Freight Transportation with drones in non-segregated airspace

Unmanned autonomous aircraft have reached sophisticated technologies and can have security systems that allow them to be used in controlled airspace, ie civil aviation.

The dimensions of these automatic aircraft range from those of “model aircraft” to those of real airplanes capable of carrying significant weights. In the world there is a real race, being the business associated with transport with drones a very high business.

However, safety aspects must be taken care of for the citizen and for the territory, for which technologies are being developed, including satellite technologies, aimed at guaranteeing maximum flight safety, even with flights of many hundreds of kilometers. Moreover, the operational aspects will be fundamental to guarantee safe and effective use. On the other hand, the regulations must also be developed to allow the best use of this technology.

Report by Antonio Errico, AOS

The Italian Institute for Navigation, Rome, organized a workshop on “Freight Transportation with drones in non-segregated airspace”. Introduced by Mrs. Palmira Petrrocelli, IIN President and Ing. Mario Caporale, IIN Vice President, Mr. Panagiotis (Panos) Xefteris, General Manager at Eurotech Aerospace Consultants and Ing. Cesare Dionisio discussed the theme. (presentation here)

Unmanned aircraft were created for military use and are still used both in war zones and in controlled areas for military operations. The Drone phenomenon is constantly growing and today they are also used in many civil applications, from archaeological surveys to aerial shootings, but it seems also there will be a future for them to transport goods.

There is therefore the need to regulate the use of drones, as they are real aircraft flying on the airspace, in order to guarantee the safety of air traffic and people on the territory.

The term drone is an English term incorporating all types of these aircraft. The correct term is UAS (Unmanned Aerial Systems) which include the RPAS (Remotely-Piloted Aircraft Systems) which are systems whose pilots operate in remote through a ground control station, called GCS (Ground-Control System) and the UAS without remote pilot, or completely autonomous aircraft. In that case, we go to the so-called artificial intelligence, whose technology is still under the Military Dominion. In the near future, however, it could be possible to extend also to the civil sphere.

Many complex aspects need to be addressed. As said, the safety aspects for the citizen and for the territory are being taken care of, for which the technologies are developing, including the satellite ones, aimed at guaranteeing the maximum safety of flight, even with flight routes of many hundreds of Kilometers. Operational aspects are also essential to ensure safe and effective use. Fundamental in the case of RPAS is the training and certification of the “pilot” on the ground. Other important aspects are also those concerning noise, privacy, and even environmental pollution. Europe has been endowed with a directive of 2015 and is already working to achieve these systems operational in the civil Aviation area by 2020.

The first part of the seminar presented by Ing. Xefteris, has been dedicated to the definition of what applications, operations and requirements are needed to fly these aircraft. In the second part, on the other hand, Ing. Dionisio has presented what is being developed in the field of communications, with particular reference to a new frequency band in C range, which provides for the first time an integration between terrestrial and spatial communications.

In order to synthetize and also because it is the field that currently offers the greatest possibilities of development and business, applications have been presented on systems of more than 150 kg, which of course offer a much more substantial freight transport. Then, fixed-wing cargo systems have been considered, which in terms of the use of unsegregated airspace are the most complicated systems, also because they have to land in a runway.

The systems considered are the RPAS, which within the UAS are those that are always equipped with a pilot at the controls, albeit on the ground, because now they are the only ones who can meet the necessary safety requirements to be able to access the airspace not segregated.

Therefore, the idea that is currently being pursued for possible developments is that of RPAS. The RPAS has a number of advantages that are below summarized:

• Does not contain, or need, a qualified pilot on board
• Can enter environments that are dangerous to human life
• Reduce the exposure risk of the aircraft operator
• Can stay in the air for up to 30 hours, performing an aerial work day-after-day, night-after-night in complete darkness, or, in fog, under computer control
• Performing a variety of missions as manned aircraft do but with more operational cost-effectiveness
• Can be programmed to complete the mission autonomously even when contact with its RPS is lost.

However, they have also some disadvantages that can be summed up in:

• May cause the collateral damage such as killing the civilians and damaging the civilian property
• Loss of Link
• Subjected to Cyber Attack
• Costly Technology to substitute human abilities and interactions on board of the aircraft (manned A/C)
• Complex Infrastructure to satisfy Aviation safety requirements

Some architectural typologies have been described, in which the avoidance collision service is important, both in the presence of an ATC (Air Traffic Control) and in case of absence, for which there is the need to identify possible obstacles, then to have a detect and avoid technology. Depending on the architecture, the Remote Pilot System (RPS) can generally be three types: fixed, transportable and mobile RPS.

Also important is the classification of the Data links for the pilot’s communications with the vehicle, for the command and control functions.

The Conops (Concept of Operations) scenarios has been described, together with the typical requirements needed to operate in the air transport context, the main physical operational elements, the main stakeholders and the functional interfaces.

With regard to the radio communication requirements for Safe UAS/RPAS Operations, these must be in accordance with ITU-R M. 2171 titled. Deployment of UAS/RPAS requires access to both terrestrial and satellite spectrum for LOS and BLOS modes of operation in the non-segregated airspace. The maximum amount of spectrum required for UAS/RPAS are:

1. 34 MHz for terrestrial systems,
2. 56 MHz for satellite systems.

The key issue for UAS/RPAS operations of whatever mission scenario is to secure that UA/RPA flight within civilian non-segregated air traffic shall:

1. integrate seamlessly into current air traffic control (ATC) procedures;
2. maintain safety-of-flight levels.

Some considerations on the data link redundancy have been made. Safe operations of UAS/RPAS in non-segregated airspace may need independent back-up communications to ensure high reliability of the critical communications links. Configuration options may include, “cold standby”, “hot standby” and “dual operation”.

Cargo Transport RPAS essential requirements domains for operations in the airspace.

Any Cargo Transport RPAS Project contains eleven Fundamental Action or Requirements Domains which currently represent the thematic and technological challenges of all RPAS Worldwide and on which the entire work of any Cargo Transport RPAS Project shall be oriented. These eleven Requirement Domains have as follows:

• Cargo Transport RPAS Initial e Continuous Airworthiness
• Cargo Transport RPAS Flight Conditions and Limitations
• Cargo Transport RPAS Remote Pilot Stations (RPS)
• Cargo Transport RPAS Remote Pilot Qualification
• Cargo Transport RPAS Human Factors
• Cargo Transport RPAS Operation and Operator’s Responsibilities
• Cargo Transport RPAS Command and Control (C2) Link
• ATC Communication with the Cargo Transport RPAS
• Rules of the Air and Detect and Avoid (DAA) Systems
• Integration of Cargo Transport RPAS Operation into ATM
• Use of Aerodromes, dedicated Logistics RPAS Systems and Maintenance

Regarding communications, we start to see the first studies of integrated communications between terrestrial and space systems.

The World Radio Conference 2012 has allocated protected spectrum for UAV C2. So far, no European UAV C2 civil data links have been proposed for frequency bands 5030‐5091 MHz.

This band was therefore internationally recognised as one of the bands that can be used for the implementation of unmanned aircraft (UA) Control and Non-Payload Communications (CNPC) links via both terrestrial and satellite systems.

Civil aviation authorities will not allow UAV operations without certified LOS and BLOS links and terminals therefore it is important that new standardized and integrated data link for certification is conceived and designed.

It has been provided the system design status of the C-band application for UAV Communications as described in the public documentation from the relevant organizations (ICAO, ITU, RTCA, etc.). Currently no satellite exists in this C-band.

Technical/Regulatory barriers for UAV operations in non-segregated areas have been summarized as follows:

• Separation Assurance/Sense and Avoid issues implementation (interoperation with ATC and keep separation)
• Human Systems Integration (lack of rules and adequate ground stations)
• Certification (lack of airworthiness requirements and safety-related data)
• Communications (lack of standard, certifiable data links and aviation safety spectrum to operate such links for civil UAS control communications.)

The loss or compromise of the CNPC link supporting safety critical functions has potentially catastrophic consequences. It is important the safe integration of UA into the Airspace system in both the LOS (Line of Sight) and BLOS (Beyond Line of Sight) segments.

ICAO (International Civil Aviation Organization) has determined that the CNPC link must operate over protected aviation spectrum, which the FSS (Fixed Satellite Service) allocation does not meet. ICAO has deemed the CNPC function to be safety critical and has mandated that aviation safety spectrum must be used for this function.

Currently we have two bandwidth LOS systems, the first one between 960 and 977 MHz that is already operational and the other one btw 5030 and 5091 MHz.

Currently the topic is the lack of certified and reliable communication systems that must operate in protected bandwidth. If the link is compromised, the UAV flight is compromised. Then it is important not to lose the link and we must have some procedures to put in place in case of failure, in order to recover the link.

The main Issues for UAV Communications have been identified, such as:

• Availability: Measures against asset denial. It includes detection of interference and attacks (dynamic power control narrow channels, dynamic frequency selection, frequency hopping, etc.).
• Integrity and Confidentiality by authentication and cryptography. – In today’s telecommunication environment, marked by various threats, jamming, unauthorized transmission monitoring / eavesdropping, miss-use of the existing communication networks and outright theft of the identity of the parties involved in communications and of the information they exchange, there is an ever-increasing need to protect the security of the communications
• Quality of service – Quality of service should be adaptive to the difference classes of services and to the environment characteristics.
• Link Loss and Operational Security – The loss of a data link must be addressed by a link-loss procedure. It is important that the aircraft always operate in a predictable manner. From the survey, it emerged that the most common link-loss procedure is for the aircraft to fly to a predefined location. Once at the predefined location, the UAS can loiter until the link is restored, it can autonomously land, or it can be remotely piloted via secondary data link. For additional secure communication proof, one approach is for the UAV to acknowledge or echo all commands it receives.

Conclusions

• UAV communication in the C-band can be a good opportunity to conceive an integrated satellite and ground communication system since the beginning embedded with high degree of safety, availability and integrity.
• The solution should take into account several constraints coming from frequency spectrum, interference, geography, international & national rules and STDs.
• The availability of certified data links is essential to operate UAV in non-segregated areas i.e. leave them to operate in civil aviation traffic.

Ultimately, in view of the increasing evolution of drones, the challenge of the near future will be to develop a technology capable of making safe the flight of such drones in civil airspace, through the adoption of appropriate operating procedures and the use of communication systems, able to provide support also to mission planning and emergency management.

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Ing. Xefteris, of Greek origin, obtained a military flight certificate in Greece, he graduated in Aerospace Engineering in USA, Arizona, and later in Aeronautical Engineering in Rome. He has been an Italian citizen since 1984. He has worked for many years in the aerospace industry. He is the author of numerous publications in the sector. He also holds the honor of Commendatore della Repubblica Italiana.

Ing. Dionisio graduated in Electronic Engineering in Rome, with a specialization in Computer technology. He worked in aerospace for more than 35 years in various national industries and participated in numerous European and international projects. He collaborated for the definition of space communication policy in the Community. Currently he works as a consultant for the development of the aerospace business. He is the author of many publications and participates as a lecturer at the II level Master of the University of Tor Vergata on telecommunications, navigation and Earth observation.