PRESENTATION BY P. XEFTERIS AND C. DIONISIO FOR THE ITALIAN INSTITUTE OF NAVIGATION. IT PROVIDES AN OVERVIEW OF ISSUES RELATED TO OPERATIONS AND TECHNOLOGIES FOR CARGO TRANSPORT UAVs OVER 150kG MGTW
OVERVIEW OF A CARGO TRANSPORT RPAS INSERTION IN NON-SEGREGATED AIRSPACE, CONOPS AND RELATED CRITICAL OPERATIONAL AND REGULATORY ISSUES
1.
2. PART A: UAS/RPAS FUNDAMENTALS AND REPRESENTATIVE CONOPS (P. XEFTERIS)
A.1) UAS/RPAS Basics-Functional, Operational Definitions and Terminology
A.2) UAS/ RPAS Categorization, Missions and Airspace Class Insertion Overview
A.3) UAS/RPAS General Functional Architecture and Critical Enabling Technologies Issues
A.4) CT-UAS/RPAS Concept of Operations (CONOPS) in LOS and BLOS and Representative Scenarios
A.5) CT-UAS/RPAS Overview of Critical Regulatory Issues
PART B : UAS/RPAS LOS AND BLOS OPERATIONS SYSTEM ARCHITECTURE
(C. DIONISIO)
B.1) CT-UAS/RPAS C3 Link System Requirements and Architectural Overview
B.2) CT-UAS/RPAS Data Link Frequency Allocation and Management Issues
B.3) CT-UAS/RPAS Data Link LOS and BLOS (Satellite) On-Board and Ground Terminal Concept Overview
4. WHAT IS A REMOTELY PILOTED AIRCRAFT SYSTEM OR REMOTELY PILOTED AIRBORNE SYSTEM (RPAS) ?
In accordance with the ICAO Doc. No. 10019 AN/507 a Remotely Piloted Aircraft System (RPAS) is a major subset
category of the Unmanned Aircraft Systems (UAS) family.
RPAS is an integrated aerial system which is composed of an aircraft without a human pilot aboard (RPA), a
ground-based controller or Ground Control Station (GCS) or Remote Pilot Station (RPS), and a link system of
Command, Control and Communications (C3 Link) Data/Voice between the RPA-RPS-ATC/ATM.
5. In accordance with ICAO the Remotely Piloted Aircraft (RPA) as an aircraft shall be piloted by a licensed
Remote Pilot (RP) who operates at a Remote Pilot Station (RPS) located external to the aircraft (i.e. ground).
The RP controls and monitors the aircraft most of the time of flight and can respond to instructions issued by
Air Traffic Control (ATC) under an Air Traffic Management (ATM) system in a regulated airspace environment as
at least manned aircraft do.
The RP communicates via Voice /Data Link during the operations, and has direct responsibility for the safe
functional and operational conduct of the RPA throughout the flight envelope of its mission profile.
It is expected that RPASs are compatible with the way “manned aviation” operations are carried out, while
interacting with ATS and with other aircraft (Manned and/or Unmanned), and maintain the current and foreseen
safety levels in aviation.
Command, Control & Communication
Link (C3 LINK)
RPA RPS
ATC/ATM
6. Some Examples of UAV/RPAS Missions
MILITARY
Intelligence, Surveillance, Reconnaissance (ISR);
Weapons Platform;
Cargo Transport and Logistics Management
Natural Disaster Support
STATE
(Non-Military)
Border Surveillance;
Police and Security support;
Rescue Support;
Fisheries Patrol;
Meteorological Research and hurricane/typhoon monitoring;
Natural and disaster support:
State Special Transport
Air Cargo Transport and Logistics
Advertising; Aerial Photography; Cinema/Media applications;
Agricultural Monitoring; insecticide and Fertiliser application;
Forest Fire Operations; wildlife census;
Critical infrastructure inspection; terrain mapping;
Oil and Gas Pipeline Monitoring
Emergency Medical Support 6
9. NOW LET’S CLEAR UP SOME MYTHS AND MISCONCEPTIONS SURROUNDING THE REMOTELY PILOTED
AIRCRAFT SYSTEMS (RPAS)
MYTH 1 : RPAS ARE DRONES
Historically, DRONES are Conceived and are in Use by the Military as dedicated AERIAL TARGETS for Combat
Training since 1936. Drones can be deployed once and after they have been targetted are completely destroyed
and cannot be re-used while UAS/RPAS are Re-demployable as any other Manned Aerial System in the inventory
of an operator . Some Drone examples are:
Firebee BQM-34A MD QF-4E LM QF- 16CNORTHROP AT
Where obviously an RPAS is an Aerial System that Performs Missions and Operates in an
Environment in a Similar Manner as a Manned Aircraft
10. MYTH 3: RPAS ONLY SUPPORT INFORMATION, SURVEILLANCE AND RECONNAISSANCE MISSIONS
RPAS, In Both Military and Civilian Operations Support all Known Manned Aircraft Missions with the exception (for
the time being) of Passenger/Personnel Transportation.
MYTH 4: OPERATING AN RPA IS LIKE A VIDEO OR VIRTUAL REALITY GAME
The RPA is Flown exactly as a Manned Aircraft and can be subjected to all kinds of complex Mission
Modifications, Flight Replanning and Emergency Conditions at any time and under a variety of different
parameters not forseen during the original Flight Planning. In Virtual Reality Games, such as air simulations, the
embedded program and its scenarios are using fixed and simpler parameters than an RPAS and of course safety
of beings and means isn’t the issue for the player.
MYTH 2 : RPAS DOESN’T ADHERE TO THE SAME RULES AND REGULATIONS AS MANNED AIRCRAFT
The RPASs Operate in the same Airspace Categories as Manned Aircraft do and must respect the same Rules of
the Air and sometimes they will fly under more stringent Regulations than Manned Aircraft. In general RPAS
follows all technological guidelines and evolutions of Manned Aircraft in order to be inserted in a Regulated Traffic
and not Visa Versa. The only difference, from the pilot point of view, is that of a fatal accident of a RPA where the
Remote Pilot won’t be among the victims but bares exactly the same responsibilities as manned aircraft operators
do. These issues are also the main subject of this Presentation.
11. Advantages of RPAS
The advantages of using an RPAS, relative to use of a manned aircraft, are that the RPAS:
does not contain, or need, a qualified pilot on board
can enter environments that are dangerous to human life
reduces 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.
Disadvantages of RPAS
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
12. A.2 UAS/ RPAS Categorization, Missions and
Airspace Class Insertion Overview
13. * MGTW = Maximum Gross Take-off Weight, ** N.O.A. = Normal Operating Altitude, *** AGL = Above Ground Level , **** MSL= Mean Sea Level
Typical Unmanned Aircraft Systems (UAS) Categorization by MGTW and Operational Performance
14. UAS/RPAS Categories by Operational Designations, Altitude and Endurance
(Source: NASA)
Airspace Classes in Accordance with ICAO Annex 11, Appendix 4
15. ATC and Collision Avoidance issues in the various Airspace Classes
ECAC has classified the airspace up to FL660 as follows:
Above FL 195 harmonized classification (Class C).
Below FL 195 predominance of Class C and D
Terminal Maneuvering Area (TMA) and Control Zone (CTR)
prevalence of Class C and D with some cases of Class A
Few cases of Class B and E
Class G available normally below FL 135
16. General Aviation Airport Categories ( ICAO ANNEX 14 )
Role Description
National Supports the national state system by providing access to national and international routes in
multiple states. It provides Passenger and Cargo Services.
Regional Supports regional economies by connecting communities to state markets. It provides Passenger
and Cargo Services.
Local Supplements communities by providing access to primarily state markets. It may also provide some
cargo services.
Basic Links the community with the national airport system and supports general aviation activities (e.g.,
emergency services, charter or critical passenger service, cargo operations, flight training and
personal flying).
Unclassified Provides access to the aviation system. It may include aerodromes with prepared and/or unprepared
runways and/or minor airfields.
17. CARGO TRANSPORT RPAS FUNDAMENTAL REQUIREMENTS DOMAINS FOR OPERATIONS IN THE AIRSPACE
Any Cargo Transport RPAS Project contains eleven (11) 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 (11) Requirement Domains have as follows:
CARGO TRANSPORT RPAS
PROJECT ACTION DOMAINS
1) Cargo Transport RPAS Initial e Continuous Airworthiness
2) Cargo Transport RPAS Flight Conditions and Limitations
3) Cargo Transport RPAS Remote Pilot Stations (RPS)
4) Cargo Transport RPAS Remote Pilot Qualification
5) Cargo Transport RPAS Human Factors
6) Cargo Transport RPAS Operation and Operator’s Responsibilities
7) Cargo Transport RPAS Command and Control (C2) Link
8) ATC Communication with the Cargo Transport RPAS
9) Rules of the Air and Detect and Avoid (DAA) Systems
10) Integration of Cargo Transport RPAS Operation into ATM
11) Use of Aerodromes, dedicated Logistics RPAS Systems and Maintenance
NOTE THAT THE CT-RPAS DESIGN, AIRSPACE OPERATIONS AND ITS RELATED REGULATORY FRAME WILL BE BASED ON THE
RESULTS OF GAP ANALYSIS AND TRADE-OFFs WITHIN ALL 11 REQUIREMENT DOMAINS BETWEEN MANNED AND UNMANNED
AIR CARGO SYSTEMS AND IN TERMS OF COMMONALITIES, NON-COMMONALITIES AND/OR NEW DEVELOPMENTS.
18. A.3 UAS/RPAS General Functional Architecture
and Critical Enabling Technologies Issues
21. The Cargo Transport RPAS over 150Kg. MGTW Remote Pilot Station (RPS) will usually be of three (3) types (common also to all
RPAS) depending on the size, configuration, mission, operational need and/or operational flexibility, namely:
1) Fixed RPS which is a permanent station with facilities usually located to a centralized operational hub and can handle an
elevated number of the same type and/or different type CT-RPAs at the same time.
2) Transportable RPS which is a fixed station after has been transported by air or sea or road and installed in a preselected
location for CT-RPAS operations. Depending on its characteristics it can handle 2 or more CT-RPAs at the same time.
3) Mobile RPS is a self-propelled station which, depending on its design, can usually handle two (2) CT-RPAs at the same time
doing Aerial Work and one (1) probably in Ferry Flight.
RPAS Remote Pilot Station (RPS) Typology
22. UAS/RPAS CNPC Information Flows between Pilot and UA
Schematic (Source RTCA 228)
UAS/RPAS Data Links Classification and Operational
Description Schematic
23. Control and Non-Payload Communications (CNPC) Link: This link is the carrier of all logical data flows
associated with the command and control of the RPA flight and the health and usage monitoring of all
RPA systems, subsystems and components and the management of the CNPC link. Since the
communications are part of controlling the RPA, they are also included within this system. This link is not
dedicated to the mission payload(s) data and therefore doesn’t carry any payload information. The CPNC
Link compared to the payload links, carries signals that are expected to be relatively narrowband, with
the possible exception of the situation awareness function enhancing video streams. The CNPC link shall
require to reside in a protected spectrum and managed by the Civil Aviation Regulatory Authority (e.g.
EASA); and
Cargo Payload Data Link: This link is the carrier of all logical data flows which associated with the cargo
payload package of the CT-RPA. It is generally expected to be broadband compared to the CNPC signals.
Since this link doesn’t contain safety-of-flight information, it doesn’t require to be in aviation safety
protected spectrum. The data transmitted by this link assists the Remote Cargo Load Master (RCLM) to
Control, Monitor and Handle the deliverable cargo payload and check the cargo bay area and its related
means.
DATA LINK TYPOLOGY
24. The CNPC link is decomposed into two (2) logical elements, namely:
1) RP/ATC Communications Link: it supports ATC by carrying:
a) Voice communications between pilots and ATC/ other Airspace users
b) Data communications (e.g. CPDLC)
1) CT-RPAS Control Link: this link carries safety-related information between the pilot in a RPS and the RPA. The
control link is further decomposed into two logical elements, namely:
2.1) Tele-command Link: which carries from the RP to the RPA:
a) Information required to control the RPA flight trajectory
b) Information required to control all RPA systems for safe flight
2.2) Telemetry Link: This is a downlink that carries, from the RPA to the RP, information required for the safe flight
of the RPA and as such shall include the following:
a) RPA Location, attitude and speed
b) RPA subsystems operating modes and status
c) Data from onboard NAVAIDS (Navigational Aids)
d) Target tracking data required by the Detect and Avoid (DAA) subsystem of the RPA
e) Data from an onboard the RPA Airborne Weather Radar (AWR) (if present on the RPA)
f) Video stream from the onboard situational-awareness-enhancing video camera (if present and if the CNPC link is
being used for that purpose).
CNPC DATA LINK TYPOLOGY
26. The overall parameters of the CT-RPAS CONOPS Scenarios that will be involved and are used in this document, are the:
Operator’s (User) Concept of Operations (including Infrastructures and Logistics),
CT-RPAS Capabilities and Performance to carry out the operator’s Cargo Transport missions, and
Overall Airspace Insertion Scenario during the various Phases of Flight.
CT-RPAS CONOPS SCENARIOS MAIN PARAMETERS
27. The Cargo Transport RPAS(CT-RPAS) shall be considered for the time being as a new addition and complementary element of
the overall current Air Cargo Transport system. In this context, the Air Cargo Transport Concept of Operations (CONOPS),
utilizing dedicated RPAS configurations, it is assumed to be composed of three (3) Main Physical Operational Elements,
namely:
1) The Operating CT-RPAS* Element encompasses the Remotely Piloted Aircraft (RPA) in a Cargo Transport Configuration
and Remote Pilot Stations (RPS) operating in LOS and/or BLOS mode by means of a Control and Non-Payload
Communications (CNPC) Link (UP and DOWN Data and Voice Link) utilizing for this purpose a Terrestrial and/or Satellite
based Network for Command, Control, Communications, Sense and Avoid (or Detect and Avoid) services covering all non-
segregated airspace classes, all integration cases and flight phases.
1) The CT-RPAS dedicated Integrated Logistic Support (ILS) Infrastructure* Element will guarantee system supportability,
availability and safety throughout the CT-RPAS Operational Life-Cycle.
1) The dedicated Air Cargo System Operational Infrastructure (ACSOI) Element will guarantee the RPAS Air Cargo Services
Business Model at Regional, Continental and Inter-Continental Levels within the current Air Cargo System and its
established regulatory requirements. The ACSOI segment also includes the operational interfaces with aerodromes and
their Infrastructures.
*NOTE: The Elements 1) and 2) together compose the Totally Integrated CT-RPAS Segment which in its turn is fully integrated
with the ACSOI Element in order to satisfy the RPAS Air Cargo Services Business Model.
Cargo Transport RPAS CONOPS- Main Physical Operational Elements Definition
28. Cargo Transport RPAS Operations Main Stakeholders and Functional Interfaces
The main Stakeholders (actors) of the RPAS CONOPS are those who are directly and indirectly involved in the Air Cargo
Operations which are the:
1. Direct CT-RPAS Stakeholders
a) Cargo Transport RPAS Provider (Industrial Actor)
b) Cargo Transport RPAS Operator ( Air Cargo Carrier Actor)*
c) Cargo Transport Logistics (Packaging/Handling/Storage) Services Provider*
d) CNPC Link Services Provider(s) (Terrestrial and Satellite Network Actor(s)support to the CT-RPAS Operator)
e) Cargo Content Provider (Owner/Deliverer of the Cargo Content)**
f) Cargo Content End Customer (Recipient of the Cargo who can be a Private and/or Institutional Entity)**
NOTE: * The Cargo Transport Logistics Provider may coincide with the Cargo Transport RPAS Operator
** The Cargo Content Deliverer may coincide with the Cargo Content Recipient
1. Indirect CT-RPAS Stakeholders
a) ATC/ATM Traffic Separation and Management Services Provider(s) who supports the CT-RPAS Operator
b) Airport Authority and/or Airport Services Provider who supports the CT-RPAS Operator
c) Regulatory/Operations Authorization Provider(s) ( Civil Aviation Authorities who Certify both the Industrial and
Operator Actors)
29. CT-RPAS CONOPS- Requirement Categories and Management Functions Overview
Requirements Category Description
Operational Scenario
Functional
Operations Typology, Flight Phases, RPAS Segments, Airspace, Aerodromes, Flight
Envelope, Safety, Coverage Area, Cargo Transport Scenarios, Air Cargo Transport Services
and Logistics
Performance RPA, RPS, Link Availability, Latency, Continuity, Integrity, Capacity, Throughput.
Security Confidentiality, authentication, integrity, availability.
Regulatory Spectrum, Frequency Mechanism, Bandwidth
Function Description
Communicate Voice, data and light signal exchanges between ATC and the RPS to communicate instructions and
responses
Control Relates to the control link between the RPA and the RPS, and includes telemetry information
confirming aircraft control status and health.
Navigate Pertains to any reference cues used by the RPA or pilot to determine orientation.
Avoid Any action taken by the aircraft to keep safely away from moving and stationary objects (e.g. terrain,
clouds, aircraft, people, structures, etc.) and from unauthorized surface areas or airspace.
30. An over 150kg MGTW Cargo Transport RPAS depending on its configuration, endurance and performance characteristics, it
will be mainly capable to perform a cargo transportation mission in both LOS and BLOS modes of operation utilizing a C3 Data
Link at allocated specific Terrestrial and Satcom Band frequencies spectrum within an adequate non-segregated (controlled
and uncontrolled) airspace class at a:
a) Regional and/or National Level
b) Continental Level (i.e. ECAC Countries)
c) Inter-Continental Level (including Over Oceanic Flights such as from EU to Africa or EU to N. America etc.)
The key issue for the Cargo Transport RPAS operations at whatever of the above levels is to reassure aviation authorities that
Air Cargo Flight by an RPAS flight within civilian air traffic will:
a) Integrate seamlessly into current air traffic control (ATC) procedures;
b) Maintain civil aviation safety-of-flight levels.
For safe operations of the Cargo Transport RPA under LOS and BLOS conditions, three types of radio-communications
between the RPA and the CGS/RPS are required, (depending on the RPAS design characteristics) which are as follows:
a) Radio-communications in conjunction with air traffic control relay;
b) Radio-communications for RPA command and control;
c) Radio-communications in support of the Sense and Avoid or Detect and Avoid (DAA) function.
Cargo Transport RPAS Required Operational Coverage Capability Issues
32. Various Examples of Fixed Wing Cargo Transport RPAS of over 150Kg. MGTW Payload Access Doors and Stores
Configurations
33. CAT. RPA SIZE No. OF
OPERATING RPA IN
NON-SEGREGATED
AIRSPACE
BY 2030
(60% OF THE TOTAL)
No. OF
OPERATING CT- RPAs IN
NON-SEGREGATED
AIRSPACE BY 2030
(20% OF THE TOTAL
OPERATING RPAs)
DENSITY
OF
ALL RPA/ Sq.Km
DENSITY
OF
CARGO
TRANSPORT
RPA/ Sq.Km
LOS
SCENARIO
FOR
CARGO TRANSPORT
RPAS
BLOS SCENARIO
ALL RPA/CT-RPA
PER SPOT BEAM
(GEO-SAT WITH 40
SPOT BEAMS)
5 Medium 2028 406 0,000156 0,0000521 406/0,0000521 51/10
6 Large 837 167 0,000064 0,0000214 167/0,0000214 21/4
Total Medium and Large RPAs and CT-RPAs (in red) Operating Population Numbers and Densities that
Need to be Supported during Operations
34. Cargo Transport RPAS CONOPS - Airspace Coverage Cells for LOS and BLOS Operations
46. Example of an UA/RPA Cargo Transport Mission from Hub (Airport A) to Hub Connection (Airport B) Representative Scenario
(ATC-Participating)
47. Example Cargo Delivery Scenario from Hub (Airport A) to not-Hub Connection (Airport X) and not-Hub (Airport X) to Hub
Connection (Airport A) CONOPS Representative Scenario
48. Cargo Emergency Delivery from Hub (Airport A)/not-hub (Airport X) to Air Drop Zone(s) CONOPS Representative Scenario
50. Types and Means of Airdrop Operations
There are three main types of airdrop in manned aviation which they are also applicable to unmanned aviation with some variations to some
operational procedures so as to safeguard safety and security. Each type may be performed via several methods, as follows:
a) Low-Velocity Airdrop is the delivery of a load involving parachutes that are designed to slow down the load as much as possible to ensure it
impacts the ground with minimal force. This type of airdrop is used for delicate goods, tools, equipment and large items.
b) High-Velocity Airdrop is the delivery of a load involving a parachute meant to stabilize its fall. The parachute will slow the load to some
degree but not to the extent of a Low-Velocity airdrop as High-Velocity airdrops are used for durable items such as conserved or packed
food or first aid goods. LAPES (Low Altitude Parachute Extraction System) is a variation of Heavy Cargo drop where the aircraft almost
completes a touch-and-go type pattern (without actually touching the ground) and the load is ejected at an extremely low altitude.
c) Free Fall Airdrop is an airdrop with no parachute at all like external store very low cost shaped container .
The method of airdrop refers to the way the load leaves the aircraft. There are three main methods of airdrop currently used in military
operations.
a) Auto Extraction airdrops use an extraction parachute to pull the load out of the aircraft end of the airplane. In this method, an extraction
parachute is deployed behind the aircraft which pulls the load out and cargo parachutes are deployed to slow the load. Extraction drops are
usually Low-Velocity airdrops, with rare exceptions (e.g. Low Altitude Parachute Extraction System).
a) Gravity airdrops use gravity in the sense that the attitude of the aircraft at the time of the drop causes the load to roll out of the plane like a
sled down a hill. The most common use of a gravity airdrop is for the Container Delivery System (CDS) bundle.
a) Door bundle drops are typical airdrop methods. In the case of RPA and in absence of on-board personnel, a door bundle airdrop will be
performed by the Remote Loadmaster or Remote Pilot from the RPS or autonomously and in automatic by using in both cases an on-board
computerized floor rail system which will push out the load in sequence and at the appropriate time.
51. Cargo Transport RPAS CONOPS Critical Assets - Field Support in Emergency Missions
1)Field support at the airport of entry: Normally, all international and/or major national airports have provisions to support
aircraft; however, demand may quickly exceed the supply and storage capacity of field support items such as fuel and/or
other consumables. Local airport authorities should be able to indicate whether or not the necessary field support could
become a limiting factor. When in doubt, the flight planning process should take possible shortages into account - plan
flights so that they do not have e.g. to refuel at the airport of entry.
2)Field Support at the operations base: In regional operations, the availability of field support is a significant factor in
selecting the operations' base. Where local authorities cannot guarantee an adequate field support such as fuel and/or other
consumables supply, the possibility of cooperating with other support actors in establishing or identifying alternate support
services. Where the emergency operations base is a governmental base, field support may be readily available but
administrative problems may arise in terms of the ability to purchase the necessary means or services. Moreover, it must be
verified whether or not the airport has the technical capacity to support the CT-RPA with e.g. pressure fueling vs. gravity feed,
appropriate fuel etc. .
3)Field Support at delivery airfields: If the delivery airfield is a rarely-used airfield, field support may be a problem. The
decision on whether or not to use these types of airfields is dependent on their distance from the operations' base and the
type of RPA to be used for regional flights. In some cases field support items such as fuel and/or other consumables can be
stored locally but, wherever possible, this should be undertaken in cooperation with professional operators.
54. Category Group 5 and 6 UAS/RPAS General Operational and Functional Requirements per Flight Phase
55. Radiocommunication Requirements for Safe UAS/RPAS Operations
In accordance with ITU-R M.2171 Methodologies, specifically with Methodology 2. 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:
a) 34 MHz for terrestrial systems,
b) 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:
a) integrate seamlessly into current air traffic control (ATC) procedures;
b) maintain safety-of-flight levels.
Summary of Radio-communication Services Required per UAS/RPAS Type/Ops Mode and Airspace Class
56. Link Redundancy Considerations
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”.
1) Cold Standby: where one link is working and carrying all the message traffic, the other link is powered down. In
the event the first link is lost, before the standby link can be used, it needs to power up and initiate the link
connection/log-in procedure to establish a connection to the other end of the link (e.g. at the GCS/RPS or UA/RPA).
This may involve a sign-in protocol with any third party network provider. The time delay associated with this
procedure should be sufficiently short to avoid the need to trigger the lost Link procedure;
2) Hot Standby: where both links are powered and connected and immediately available, although only one is being
used to transfer Link data at any time. (The standby may be transferring low rate data to keep the link immediately
ready to take over.); and
3) Dual Operation: where all link data messages are sent on both links simultaneously and the flight computer
chooses the message from the link with the best integrity. This mode of operation minimizes the probability that
there will be an interruption in link data flow in the event of a single link interruption or failure.
It is recommended that the two links employ different frequencies/technologies (e.g. terrestrial radio line of-sight
and satellite-based BRLOS) as this will provide significantly greater protection against possible loss of the link. The
GCS/RPS should be provided with a continuous indication of the operational status of all links.
61. The International Civil Aviation Organization (ICAO) has determined that the C3 link must operate over
protected aviation spectrum. Therefore, protected aviation spectrum must be allocated for this function,
approved through the processes of the International Telecommunications Union Radio-communication Sector
(ITU-R).
Actions taken at the ITU-R 2012 World Radio-communication Conference (WRC-12) have established spectrum
resources to address the RLOS spectrum requirement among others also in the C-Band, at 5030-5091 MHz.
At the ITU-R 2015 WRC (WRC-15), BRLOS spectrum requirements were addressed by providing allocations
specifically for UAS/RPAS in Ku-Band and Ka-Band in Fixed Satellite Service (FSS) allocations. The FSS
allocation is not aviation safety spectrum, hence the use of these bands for C2 links will require a number of
special considerations in order to meet an equivalent level of safety. With WRC-15 actions completed, it is
currently possible to begin experimental studies of UAS/RPAS C2 links in Ku-Band and Ka-Band, and such
studies will be necessary to fulfill requirements imposed by WRC-15 before the UAS/RPAS C2 allocations can
be finalized probably in WRC-19 and/or WRC-23.
For C-Band, there are currently no satellites in operation providing services in the aviation band so no
experimental investigations are possible yet and therefore analytical assumptions are only possible for the
time being especially when considering UAS/RPAS operational scenarios.
63. C-band communications for UAS/RPAS
( AMS (R) S :Aeronautical Mobile Satellite (R) Service)
Ideas for an operational system architecture
List of contents:
• Introduction
• Current Requirement and architectural Overview
• Data link frequency allocation & management issues
• Data link LOS and BLOS main design issues
• Conclusions
64. Introduction
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.
Scope of this presentation is to provide 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, ect) .
Currently no satellite exists in this C-band.
65. BLOS from Satellite current used data links
BLOS C2 data links range from Ultra High Frequency (300 MHz) to Ku Band (15GHz). Ku Band SATCOM data links
are widely used for BLOS C2 system. It has a frequency range from 11.7–12.7 GHz for downlink and 14-14.5 for
uplink.
Ku Band is used by a bulk of high endurance UAS like Global Hawk, BAMS, Predator and its derivatives.
INMARSAT SATCOM data links are also used by high endurance UAS
including BAMS, Marnier and Global Hawk. It has frequency range from 1626.5–1660.5 MHz for uplink and 1525–
1559 MHz for downlink.
L Band Iridium SATCOM data links are used by smaller, low or medium endurance, research UAS. It has a
frequency range from 390 MHz–1.55 GHz
66. Current international study objectives
• Verify interference compatibility among services (in particular AMS (R) S compatibility MLS)
• Verify simultaneous communications capability for Ground-Space for CNPC (C2/C3)
• Identify and demonstrate ground/space service (BW) sharing mechanism and its
effectiveness/complementarity
• Design a suitable waveform or set of waveforms for the service
• Manage Space & Ground links diversity (dynamic, link models, ect)
• Identify an overall system design including satellite, ground stations and RPAS User Terminal
a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an input
signal for the purpose of conveying information.
72. Performance Requirements
Constrained by BW, power
density & UAV resources
Redundancy
Flexibility
Adaptability
Monitoring
= 2*(UT->GES)+2(GES->UACS)+UT
UT: UAV TERMINAL
GES: GEO SAT
UACS: CONTROL STATION
With GEO
250-300 ms
74. Main System design issues
• Satellite orbit= >GEO vs LEO
• Power density and spectrum constraints
• MLS (Microwave Landing System) compatibility
• Duplexing mechanism (share of BW/time between Tx andRx) and Communication
sharing Ground-Space
• Channel access mechanism & Modulation
• Power Amplifier operation(saturated-not saturated)
• Ground station configuration
• Number of UAV antennas/rx chains
75. SPECTRUM ALLOCATION for LOS/BLOS CNPC
TOTAL UAV BW requirement: a proposal (TBC)
LOS: 34 MHz BLOS: 56 MHz
17 MHz in L band At least 17 MHz
in C band
20 MHz in C band 36 MHz in others band (TBD)
76. LEO Comm. constellation vs GEO sats
Advantages LEO Drawbacks LEO
Lower tx power ,non directional antennas possible Higher number of satellites to get coverage
Signals Lower latency time
(GEO ~ 125 ms)
Higher on board complexity (switching, power, etc)
Direct contact in multisatellite system User terminal complexity (need to manage handover
among sats and track)
Better overall reliability in case of failure of one sat (easier
replacement)
Complex ground operations for constellation management
Lower single launch cost
Less crowed orbit positions
Complex launches for constellation deployment
Global Coverage possible
GEO ‘s not cover Polar regions (above 70° Lat)
Most of the time satellites are out operation areas (ie on
ocean,..)
Less fuel for station keeping Lower power (eclipse)
76
80. SPECTRUM SHARING MECHANISM
SCENARIO
Feeder link
(considered outside of
5030 -50 91MHz )
5030 -5091 MHz
5030 - 5091 MHz
C2 link
LOS
Gateway
C2 link
SAT
Gateway
C2 link
SAT
Payload
MLS
transmitter
C2 link
LOS User
Terminal
5030 -5091 MHz
MLS
receiver
C2 link
SAT User
Terminal
TOTAL BW requirement
LOS: 34 MHz BLOS: 56 MHz
The mitigation techniques for service compatibility include:
• frequency planning,
• geographical separation
• power control.
82. TDD Advantages
•Frequency spectrum allocation
•Use unpaired spectrum
•Adjustable tx and rx slots duration
•No diplexer
•Easier for asymmetric traffic
•Higher data rate
•Lower terminal cost
TDD Drawbacks
•Guard time (trip time, tx/rx switching, multiplexing)
•Cross-slot (inter spot) interferes
synchronization
sectorization
time slots grouping
•Inter/intra operator (ground-space) interferences
Time Division Duplex Technique
83. Half Duplex Frequency Division Duplex
• FDD usage does not limit overall system performance, but does limit the overall
combined DL+UL throughput to an individual Terminal since the link is half duplex.
• uses different RF channels for downlink and uplink, but DL and UL
must still happen at different times, just like in TDD
Frequency Division Duplex
• allows full duplex instantaneous connectivity, minimum latency
• difficult to achieve with single small BW available because of Tx and Rx
isolation (>100 dB generally). Diplexer is needed.
• allows any kind of channel access
84. ACCESS AND SHARING MECHANISMS MAY
PRESENT SEVERAL OPERATIONAL SOLUTIONS
FDD up FDD downTDD
TDD
TDMA up
FDMA down
5030 MHz
Sharing FDD and TDD in the available BW simplyfing sat diplexing
TDD but with different channel access mechanisms TDMA for UE Tx and FDMA for sat and GS tx
TIME
Broadcast/
Multicast
SporadicSignalling Normal
TRAFFIC TYPOLOGIES
MIXED
ALL TDD
LET’S CONSIDER THAT TRAFFIC IS ASYMMETRIC !
SATELLITE BW’s
5091 MHz
10 -20MHz 10 -20MHz
BW
5-20 ms
85. Access Advantage Disadvantage Guards Complexity UA power &
BW demands
FDMA
(Frequency Division
Multiple Access)
Network timing not required Intermodulation noise Guards in
frequency
Low Low
Uplink power control required
Better for continuos traffic good in
combination SCPC-DAMA
Frequency allocation difficult to
modify
TDMA
(Time Division Multiple
Access)
Max use of transponder resources Network timing & synchronization
required
Guards in
time
Medium High
No power control required Class C PA applicable
No mutual interference between
access
Better in case of low/sporadic traffic
Guarantee periodic tx
CDMA
(Code Division Multiple
Access)
Anti Jamming capability/ multipath
tolerance
Wide BW Need power
control
High High
Network timing not required
/multiple user access
synchronization required
Allow non periodic tx High PAPR
Useful for emergency and link
initialization
High interference when high number
of users
OFDMA/OFDM
(Orthogonal frequency-
division multiple access
Immunity to frequency selective
fading channels
high PAPR Guard in
frequency
High High
high spectral efficiency Sensitive to doppler shift
Immune to the multipath delay Sensitive to frequency
synchronizatin
Low inter symbol interference (ISI)
CHANNEL MULTIPLEXING
86. Wireless communication is typically subject to fading, i.e. amplitude
fluctuations over time and frequency
Fading is broadly classified into large-scale fading and small-scale fading
Small scale Fading is caused by multipath signal
propagation leading to the subsequent arrival of
multipath components (MPC) with varying phases
Large-scale fading accounts for shadowing
losses in addition to the mean path loss
Ltot = 20 log(dkm) + 20 log(fMHz) + 32:45 +La+Lssf
FADING
87. 10-3
10-6
10-4
10-5
BER
PER MIGLIORARE LE PRESTAZIONI DEL LINK O DEL BER HO DIVERSE SOLUZIONI:
- AUMENTARE EIRP (Ptx*Gtx) (ma questo sui piccoli UAV è difficile/costoso e comunque
limitato da vincoli sulle interferenze)
- MIGLIORARE LE PRESTAZIONI DI RUMORE/PROCESSING DEL RICEVITORE (costoso)
- REALIZZARE UN’ANTENNA PIU’ GRANDE IN RX (Gr) (difficile in un UAV)
- CAMBIARE FREQUENZA se possibile
- AGIRE sullo Spazio cioè Trasmettere in zone dove c’è meno attenuazione
- AGIRE sulla modulazione ordini inferiori
- AGGIUNGERE UNA CODIFICA AL SEGNALE TRASMESSO (MIGLIORE SOLUZIONE ma si
perde in DR NETTO)
Link BudgetBER improvement
Guadagno di codifica
87
I codici di autocorrezione richiedono una notevole perdita di Data Rate netto (e.g. REED SALOMON 12%,
Viterbi 100%)
Più in generale e in caso di attenuazioni atmosferiche:
88. MUDULATION TO BE PREFERRED ARE WITH CONSTANT ENVELOPE SO TO LIMIT PA NON LINEARITIES EFFECTS
The Consultative Committee for Space Data Systems (CCSDS) has standardized similar bandwidth efficient modulations for
space telemetry applications, which include, in addition to the two modulations just listed:
.Gaussian minimum shift keying (GMSK)—a type of CPM
. Filtered OQPSK modulations (aside from SOQPSK), such as square root raised cosine (SRRC) OQPSK
. 4D–8PSK–Trellis coded modulation (TCM)
other examples:
Variants of shaped offset QPSK (SOQPSK)
Variants of Feher patented QPSK (FQPSK)
MODULATION
89. Frequency band congestion and the regular increase of transmission data rates
are requiring to improve the bandwidth efficiency of Communication Systems.
Higher order modulation schemes (e.g., 8-PSK and 16-APSK) and pulse shaping (e.g.,
GMSK) are examples of current technology approaches responding to the need of
improved bandwidth efficiency.
MODULATION SPECTRAL EFFICIENCY
89
GMSK: Gaussian Minimum Shft Key, SRRC, Squa- re Root Raised Cosine
In application in which the bandwidth is limited by physical constraints, the goal is to
choose a modulation technique that gives the highest spectral efficiency while achieving a
low probability of bit error at the system output. The maximum possible spectral efficiency
is limited by the channel noise if the error is to be small.
SPECTRAL EFFICIENCY Bit rate (R) per unit of BW
90. L’efficienza spettrale comporta una riduzione della banda del segnale trasmesso che pero’ viene pagata in termini
di una maggiore sensibilità del sistema alle distorsioni. In particolare quelle prodotte nei PA dalla variazione
dell’ampiezza del segnale di ingresso.
Come si vede in figura la OQPSK riduce il problema limitando la variazione di ampiezza presente nella QPSK
Consentendo variazioni solo di 90°.
Un modo per ridurre la banda del segnale consiste nell’utilizzare segnale non di ingresso non rettangolari ma
di forma diversa per esempio a seno rialzato o gaussiano.
MODULATION SPECTRAL EFFICIENCY
Spettro QPSK
Tipo sinc(x)
Spettro QPSK con
Impulsi SRRC
Riduzione transizione
Ampiezza in OQPSK
90
91. •Symbol rate (SR)=(Data Rate + overhead+FEC) /E
•Throughput (T): Symbol Rate (R)* U (utilization factor)
BLOS BW aggregation W (according to ICAO documentation) but to be adapted to C band spotbeam space system configuration:
Total System BW = K*N*T*L*M*R
K : frequency reuse factor
N: number of Spots
T: throughput requirement (per UAV link)
M: number of UA per spotbeam
R: redundancy factor (1<R<2) dual and back up links, account also for latency margin
U: utilization factor <1 high latency request low value for U or dedicated channel to manage emergencies
E: spectral efficiency expected better than 1
L: number of two ways paths
FEC: Forward Error Correction (encoder)
OVERALL BW & CHANNELING
FOR SPACE SEGMENT
CHANNELING is fundamental to guarantee compatibility with MLS an link budget.
It should be multiple or submultiple of 300 KHz
Basically 150 KHz per channel will be operated.
92. Power amplification is a central issue in communication system design.
Linearity and efficiency are the key characteristics
AM/PM-AM/AM
NOISE REGROWTH
Doherty Amplifier allows better efficiency
With high Peak to Average Power Ratio (PAPR)
POWER AMPLIFICATION
93. IMPORTANT ISSUES FOR UAV COMMUNICATIONS
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, unauthorised
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
Potential counter measurement to improve integrity:
• Authentication
•Cryptography
•Improvement of link power budget
•Time diversity (only if separate tx are statistically independent)
•Space diversity (ie multiple antennas, to avoid blockage or multipath)
•Frequency diversity (with independent fading mechanism ie L+C)
94. Quality of service should be adaptive to the difference classes of services and to the
environment characteristics. It includes:
•QoS adaptation due to interference ACM (Adaptive Code Modulation)
•Support traffic priorities and maximize spectrum utilization
•Support different class of traffic
•Reliability mechanisms at data link layer
•Dynamic BW allocation DAMA (On DEMAND ASSIGMENT MULTIPLE ACCESS)
•Provide statistics (optional)
QUALITY of SERVICE
Demand Assigned Multiple Access (DAMA) is a technology used to assign a channel to clients that don't need
to use it constantly. DAMA systems assign communication channels based on requests issued from user
terminal to a network control system. When the circuit is no longer in use, the channels are then returned to
the central pool for reassignment to other users. Not to confuse with Multiple Access mechanism like TDMA.
95. DAMA & ACM
• DAMA protocol can be adopted in this system design but should be integrated with an
advanced RA protocol that can be better cope with unpredictable real time variable
applications and sparse traffic. In addition it should be noted that DAMA doesn’t work
well with Real time traffic when variable code is used as for instance in the ACM.
• Generally ACM in the space domain is particularly suitable for fixed application but
couldn’t be for RPAS communications.
The RPAS/UAV move with a relative high speed from one weather condition to another
one and or change beam then may find different propagation conditions from what
previously estimated.
In addition output power adaptation is limited because of ITU power density constraints.
The GEO satellite system has a latency time. That can affect the application. So it is
necessary to estimate the C/N by a closed loop approach and provide the UA position by
the GNSS but this is already foreseen as mandatory. Let’s consider that ACM works well in
low fading conditions and that the not correct evaluation of C/N might degrade the
system performances. So its application should not be acted during critical operation
97. The loss of a data link must be addressed by a link-loss procedure. It is
important that the aircraft always operates in a predictable manner. From
the survey, it was revealed 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 either 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. This will ensure the pilot-in-
command that all commands sent are received and acknowledged . Such an
approach will also notify the pilot in control if the aircraft receives commands
from an unauthorized entity.
In case the commands can be simultaneously received from both BLOS and LOS
links an a priority setting will define priorities.
LINK LOSS and Operational Security
98. EARTH
SATELLITE for C –Band communications
C-Band 6 meters antenna diamer with 40 beams
Ku/Ka antenna for feeder link communications
C-Band
Antenna
Ku band
Antenna
100. •LNA
•PA
. Filters
•diplexer
Signal conditioning/AGC
UP/Down conversion
Filtering
ADC/DAC
Antenna
Bottom
FE
SDR
TX/RX
chains
Digital
section
Signal processing
Data processing
OSI link layers
Antenna
Top
FE
SDR
TX/RX
chains
S
S
FE
SDR
TX/RX
chains
Antenna
(option)
Antenna
Bottom
(option)
Terminal Front End Design Options
UAV TERMINAL CONFIGURATION
101. 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 in considerations 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 ie leave them to operate in civil
aviation traffic.