Welcome
Introduction and explanation
OF THE UASD DICTIONARY
Subject
CONTROL AND NON-PAYLOAD COMMUNICATION (CNPC) OF UNMANNED
AIRCRAFT SYSTEMS (UASs) USING THE FIXED-SATELLITE SERVICE (FSS)
also known as
REMOTELY PILOTED AIRCRAT SYSTEM (RPAS)
COMMAND AND CONTROL (C2) LINK
The C2 of unmanned aircraft / remotely piloted aircraft using the fixed-satellite service is a complex topic involving multiple committees and organizations of the United Nations.
Sinced it has been put on the agenda of a World Radiocommunication Conference for 2015 a lot of studies have been performed assessing the possibilities, requirements, prerequisites, and responsibilities to ensure a safe and reliable operation of CNPC/C2 Links using the fixed-satellite service.
Not being compiled for all concerned members and interested parties, a common pool gathering all information, respectively, linking all available documents studies, and additional information required is missing.
This digital dictionary on the use of the fixed-satellite service for the command and control of unmanned aircraft provides a compiled information basis for all interested parties, notifying administrations, sector members, satellite operators, or competent authorities.
It supports the understanding of the regulatory, technical, and operational environment under which a safe and reliable operation of UAS CNPC links / C2 Links can work.
Furthermore, it demonstrates the obligations, and responsibilities of each entity within the system and process and highlights its duties and rights.
OBJECTIVES
This UASD-DICTIONARY collects
key elements, background
information and answers
for the safe and reliable
operation of UAS / RPAS
For this, the most important terms, concepts, and definitions for UAS and RPAS are provided, complemented by some additional documents and links.
The available reports of ITU and ICAO on that subject are linked and can be downloaded in our DOWNLOAD CENTER using the respective access regulations from either ITU or ICAO.
UASD DICTIONARY
Most RESEARCHED UAS KEY Topics
Click on topic of interest and see filterED results below
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Availability
The required probability that an operational communication transaction can be initiated when needed. It is a performance indicator to measure the probability to access the spectrum at a specific time.
Most people know this term from availability due to propagation events, however, it is a term to describe the cumulative distribution function of all time variant events. Due to the movement of the UA/RPA, all performance parameters contribute to the availability. Depending on their correlation these distributions are either multiplied or convolved.
For statistically uncorrelated and independent random variables the probability density functions are combined using convolution. This is the case for interference and propagation events which are not correlated to each other. Multiple propagation events such as uplink and downlink to the same location are multiplied because they are correlated.
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Background of the PFD masks
The PFD masks proposed in Res. 155 (Rev. WRC-19) are based on the studies carried out in the study cycle for WRC-19.
The studies followed the input of the concerned working parties 5A and 5C for technical and operational characteristics of co-frequency terrestrial radio communications services.
The protection criteria which were provided to not to be exceeded are the short and long-term criteria, as well as the Fractional Degradation of Performance (FDP). The latter is applicable according to Rec. ITU-R F.758-7 to frequencies below 15 GHz
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C2 Link
The command and control (C2) link is the data link between the remotely piloted aircraft and the remote pilot station for the purpose of managing flight. There are a variety of possible architectures and considerations in the design, security and management of the C2 Link.
RPAS C2 Link functions are usually separated into telecommand and telemetry. Telecommand comprises information coming from the remote pilot station (RPS) to the RPA (forward link). Telemetry comprises information coming from the RPA to the RPS (return link).https://skybrary.aero/sites/default/files/bookshelf/4777.pdf
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C2CSP
C2 Link communication service provider (C2CSP). An entity which provides a portion of, or all, the C2 Link service for the operation of an UAS. An UAS operator may also be its own C2CSP.
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CNPC
Control and non-payload communications (CNPC): The radio links, used to exchange information between the UA and UACS, that ensure safe, reliable, and effective UA flight operation. The functions of CNPC can be related to different types of information such as: telecommand messages, non-payload telemetry data, support for navigation aids, air traffic control voice relay, air traffic services data relay, target track data, airborne weather radar downlink data, non-payload video downlink data.
https://www.itu.int/en/ITU-R/space/snl/Documents/R-REP-M.2171-2009-PDF-E.pdf
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Continuity
The required probability that an operational communication transaction can be completed within the communication transaction time, given that the service was available at the start of the transaction. It is a performance indicator to measure the probability that once access to the spectrum is granted, the link is not interrupted for a certain period of time.
The basis is a reference time span defined for certain airspace, e.g. 5 seconds. A 90% continuity stands for the probability that a link is closed for more than e.g. 5 continuous seconds before it is interrupted, which would be in this example 90%.
It is known in the radio communication world as the second-order statistic, in particular the complementary average duration of fades.
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FREQUENCY BANDS, KU / KA
The Ku band is the frequency range from 12-18 GHz. In ITU-R the spectrum is allocated to the fixed-satellite service and hence is primarily used for satellite communications. Ku band satellites are also used for backhauls and particularly for satellite from remote locations back to a television network's studio for editing and broadcasting.
The Ka band is the corresponding higher frequency range allocated to the fixed-satellite service in the 17-30 GHz frequency ranges. For the command and control of unmanned aircraft specific bands with in the complete spectrum are selected in resolution 155. These are the frequency bands not subject to any plan and are in particular:
Ku band:
- 14-14.47 GHz (Earth-to-space) and 10.95-11.2 GHz, 11.45-11.7 GHz (space-to-Earth) (in all ITU Regions)
- 11.7-12.2 GHz (space-to-Earth)on a worldwide basis as (Region 2 only)
- 12.2-12.5 GHz (space-to-Earth) (Region 3 only)
- 12.5-12.75 GHz (space-to-Earth) (Regions 1 and 3)
Ka band:
- 29.5-30 GHz (Earth-to-space) and
- 19.7-20.2 GHz (space-to-Earth) on a worldwide basis
Ku band downlink frequencies
Ku band uplink frequencies
Ka band downlink frequencies
Ka band uplink frequencies
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FS
Fixed Service: A terrestrial radiocommunication service between specified fixed points.
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FSS
Fixed-Satellite Service: A radiocommunication service between earth stations at given positions, when one or more satellites are used; the given position may be a specified fixed point or any fixed point within specified areas; in some cases this service includes satellite-to-satellite links, which may also be operated in the inter-satellite service; the fixed-satellite service may also include feeder links for other space radiocommunication services.
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ICAO
ICAO is funded and directed by 193 national governments to support their diplomacy and cooperation in air transport as signatory states to the Chicago Convention (1944).
Its core function is to maintain an administrative and expert bureaucracy (the ICAO Secretariat) supporting these diplomatic interactions, and to research new air transport policy and standardization innovations as directed and endorsed by governments through the ICAO Assembly, or by the ICAO Council which the assembly elects.
Industry and civil society groups, and other concerned regional and international organizations, also participate in the exploration and development of new standards at ICAO in their capacity as ‘Invited Organizations’.As new priorities are identified by these stakeholders, the ICAO secretariat convenes panels, task forces, conferences and seminars to explore their technical, political, socio-economic and other aspects. It then provides governments with the best results and advice possible as they collectively and diplomatically establish new international standards and recommended practices for civil aviation internationally.
Once governments achieve diplomatic consensus around a new standard’s scope and details, it is then adopted by those same 193 countries in order to bring worldwide alignment to their national regulations, helping to realize safe, secure and sustainable air operations on a truly global basis.In addition to these core diplomatic and research capabilities, ICAO also serves as a critical coordination platform in civil aviation through its seven Regional Offices.
The stipulations ICAO standards contain never supersede the primacy of national regulatory requirements. It is always the local, national regulations which are enforced in, and by, sovereign states, and which must be legally adhered to by air operators making use of applicable airspace and airports.Contrary to many dramatic and media portrayals of UN agencies, they do not have any authority over national governments in the areas of international priority they are established for. Critiques of the UN are often rooted in allegations founded on fantastical capabilities and authorities which sovereign states would never assign to a multilateral organization.
ICAO is therefore not an international aviation regulator, just as INTERPOL is not an international police force. We cannot arbitrarily close or restrict a country’s airspace, shut down routes, or condemn airports or airlines for poor safety performance or customer service.Should a country transgress a given international standard adopted through our organization, ICAO’s function in such circumstances, consistent with our core diplomatic capabilities and role, is to help countries conduct any discussions, condemnations, sanctions, etc., they may wish to pursue, consistent with the Chicago Convention and the Articles and Annexes it contains under international law.
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ITU-R
The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for the regulation of radio communications.
Its role is to manage the international radio-frequency spectrum and satellite orbit resources and to develop standards for radiocommunication systems with the objective of ensuring the effective use of the spectrum.ITU is required, according to its constitution, to allocate spectrum and register frequency allocation, orbital positions and other parameters of satellites, “in order to avoid harmful interference between radio stations of different countries”. The international spectrum management system is therefore based on regulatory procedures for frequency coordination, notification and registration.
ITU-R has a permanent secretariat, the Radiocommunication Bureau, based at the ITU HQ in Geneva, Switzerland. The elected Director of the Bureau is Mr. Mario Maniewicz; he was first elected by the ITU membership to the directorship in 2018. [Wikipedia]
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Performance Indicators
An important part of data link safety performance is the measurement of end-to-end performance.
Data link performance assessment is based on round-trip time, availability, integrity, reliability and continuity. -
PFD Masks
A method to protect radio communications services from harmful interference is to limit the transmit power of (potentially) interfering stations. A common practice for a power limitation, especially for air or spaceborne transmitters is the use of power flux-density limits, respectively, masks which could be measured on the Earth’s surface.
Hence, the PFD limits are valid for the Earth’s surface in front of the receiver antenna to be protected and defined as a function of the angle of arrival of the interfering signal towards the victim receiver. This method enables independency on the interfering characteristics such as antenna gain envelope, altitude or velocity. Variations may occur in the reference bandwidth depending on the receiver noise bandwidth. If the victim bandwidth is larger than the interference bandwidth, then the reference bandwidth is reduced.
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QoSD
Quality of Service Delivered by the C2CSP(s) to the RPAS operator during performing the C2 Link service.
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QoSO
Quality of Service Offered is the proposed QoS by the C2CSP(s) to the RPAS operator in response to its QoSR.
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QoSR
Quality of Service Required is a statement of QoS requirements of the RPAS operator to be met or exceeded by the C2CSP(s). This QoSR is derived by the RPASP operator from the C2 Link specification in application to the specific flight and the basis for the SLAs between the RPASP operator and the C2CSP(s).
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Resolution 155
The resolution 155 was adopted by WRC-15 where the first set of requirements for the use of the geostationary satellite systems in the fixed-satellite service for the control and command of unmanned aircraft where listed.
It comprises regulatory provisions regarding the use of the FSS as is, the specific requirements for the Earth station on board the UA / RPA, the responsibilities of the affected frequency administration(s) and the requirement to use the foreseen frequencies in accordance with the Convention on International Civil Aviation (ICAO) and its Annexes that includes standards and recommended practices (SARPs) to ensure the safe and reliable operation of unmanned aircraft.
The Resolution 155 has been revised by WRC-19 and according to Resolution 171 (WRC-19) it is subject for review and – if necessary – for revision at WRC-23.
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RLP
A set of defined parameter values, appropriate to the phase of flight and airspace, that any C2 Link must achieve to enable safe RPAS operation.
The development of Required Link Performances allow States and regulatory authorities to grant operational approval for operations in specific areas on the basis of the capability to meet a given performance rather than on the basis of installation or carriage of specific communications equipment.The RLP characterizes the safety based performance required of communication capabilities that support RPAS C2 functions without reference to any specific technology and is open to new technologies. This approach is essential to the evolution of operational concepts that use emerging technologies. The RLP assesses operational communication transactions in the context of a RPAS C2 function, taking into account human interactions, system design, procedures and environmental characteristics.
- Because of the numerous variants in the design of a RPAS C2 system, including different levels of automation, message transmission protocols and control mode classes, the RLP is designed to:
- Allow the same level of integrity of the C2 transactions for a given function, or group of functions, regardless of realisation of the RPAS C2 system.
- Support the RPAS operator in contracting a communication service for RPAS C2 functions in a standardized way. - The RLP is designed in order that the RPAS C2 meets the performance or safety requirements and criteria of that airspace / operational context and needs to take into account the design of each C2 system. The RLP cannot be prescribed as an operational parameter only (e.g. landing).
The RLP is based upon “operationally significant” benchmarks which when attained assures confidence that the operational communications supporting the RPAS C2 functions will be conducted in an acceptably safe manner. The basis for the development of the RLP was the need for objective operational criteria, in the form of a “RLP type”, to evaluate a variety of communication technologies. Once these criteria have been set and accepted, a specific implementation of a RPAS C2 function including its technical and human performance may have its viability assessed against acceptable operational criteria
- RLP type is a label (e.g. RLP X) that defines a performance standard for operational communication transactions. Each RLP type denotes values for communication transaction time, continuity, availability and integrity applicable to the most stringent RPAS C2 function
- The RLP is not dependent on a specific technology; however, it is not intended to promote an unrestricted number of alternative communication technologies for one RPAS C2 function. Interoperability,
certification, safety oversight and cost considerations will be major items to contend with during such consultations.
Several factors may affect States decisions as to when a RLP type will be prescribed. These factors are based on the safety level required in a given airspace or over a populated area and may differ depending on the operation carried out. In order to achieve the benefits that are advantageous to States, communication service providers and users, there is a need to ensure consistent definition and use of communication capabilities in order to apply the RLP concept on a global basis. - Because of the numerous variants in the design of a RPAS C2 system, including different levels of automation, message transmission protocols and control mode classes, the RLP is designed to:
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RPA
Remotely Piloted Aircraft, an unmanned aircraft which is piloted from a remote pilot station.
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RPAS
Remotely piloted aircraft system, consisting of the remotely piloted aircraft (RPA), its associated remote pilot station(s) (RPS), the required C2 Link(s) including the respective infrastructure and equipment and any other component as specified in the type design.
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RPS
Remote Pilot Station, the component of the remotely piloted aircraft system containing the equipment used to pilot the remotely piloted aircraft. The RPS has two interfaces to the C2 Link, one for supporting the C2 Link User Data between RPS and RPA for performing the activities (Aviating, Communicating, Navigating, and Integrating), the other one for managing the C2 Link to maintain the required link performance during the operation of the flight.
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SARPs
Standard and Recommended Practices, contained in the Annexes of the Convention on International Civil Aviation (ICAO). The C2 Link related SARPs are contained in Annex 10, Volume VI and comprise two Parts:
- Part I with C2 Link Procedures;
- Part II with C2 Link technical and system related descriptions.
Standards and Recommended Practices for Aeronautical Telecommunications were first adopted by the Council on 30 May 1949 pursuant to the provisions of Article 37 of the Convention on International Civil Aviation (Chicago 1944) and designated as Annex 10 to the Convention. They became effective on 1 March 1950. The SARPs were based on recommendations of the Communications Division at its Third Session in January 1949.
An Annex is made up of the following component parts, not all of which, however, are necessarily found in every Annex. SARPs adopted by the Council under the provisions of the Convention are defined as follows:
- Standard: Any specification for physical characteristics, configuration, matériel, performance, personnel or procedure, the uniform application of which is recognized as necessary for the safety or regularity of international air navigation and to which Contracting States will conform in accordance with the Convention; in the event of impossibility of compliance, notification to the Council is compulsory under Article 38.
- Recommended Practice: Any specification for physical characteristics, configuration, material, performance, personnel or procedure, the uniform application of which is recognized as desirable in the interest of safety, regularity or efficiency of international air navigation, and to which Contracting States will endeavour to conform in accordance with the Convention.
- Appendices: comprising material grouped separately for convenience but forming part of the Standards and Recommended Practices adopted by the Council.
- Definitions of terms used in the Standards and Recommended Practices which are not self-explanatory in that they do not have accepted dictionary meanings. A definition does not have independent status but is an essential part of each Standard and Recommended Practice in which the term is used, since a change in the meaning of the term would affect the specification.
- Tables and Figures: add to or illustrate a Standard or Recommended Practice and which are referred to therein, form part of the associated Standard or Recommended Practice and have the same status.
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Specific Earth Station
Satellite earth station communicating in a geostationary satellite network or non-geostationary satellite system with a fixed and unchanged location inside the service area of the respective satellite network / system. Its location information is part of the coordination request and notification filings for this station.
In difference to the typical earth stations the coordination / notification of a specific earth station is to be done by the authority of the administration on whose territory the station is located.
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Typical Earth Station
Satellite earth station as part of a geostationary satellite network or non-geostationary satellite system with fixed location(s) within the service area of the associated satellite network / system. In difference to the specific earth stations with an unchanged fixed location (as given in the ITU filings) a typical earth station is fixed during its operation, but can be placed anywhere within the respective service area.
The coordination request and notification of such typical earth stations can only be carried out via the associated satellite network / system it is belonging to.
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UA
Unmanned Aircraft (UA): Designates all types of aircraft remotely controlled.
https://www.itu.int/en/ITU-R/space/snl/Documents/R-REP-M.2171-2009-PDF-E.pdf
The respective ICAO designation is RPA.
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UACS
Unmanned Aircraft Control Station (UACS): Facilities from which a UA is controlled remotely.
https://www.itu.int/en/ITU-R/space/snl/Documents/R-REP-M.2171-2009-PDF-E.pdf
The respective ICAO designation is RPS.
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UAS
Unmanned Aircraft System (UAS): Consists of the following subsystems:
- Unmanned aircraft (UA) subsystem (i.e. the aircraft itself)
- Unmanned aircraft control station (UACS) subsystem
- Air traffic control (ATC) communications subsystem (not necessarily relayed through the UA)
- Sense and avoid (S&A) subsystem
- Payload subsystem (e.g. video camera …)
https://www.itu.int/en/ITU-R/space/snl/Documents/R-REP-M.2171-2009-PDF-E.pdf
The respective ICAO designation is RPAS.
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WRC
World Radiocommunication Conferences (WRC) is the highest decision making body of the ITU-R. The WRCs are held every three to four years to review, and, if necessary, revise the Radio Regulations, the international treaty governing the use of the radio-frequency spectrum and the geostationary-satellite and non-geostationary-satellite orbits. Revisions are made on the basis of an agenda determined by the ITU Council, which takes into account recommendations made by previous world radiocommunication conferences and the study work of the ITU-R study groups following the agenda items decided by the previous WRC.
Technical
Understanding
Illustration
