/ International Civil Aviation Organization
WORKING PAPER / ACP WG-F/25 WP13

ACP Working Group F (Frequency)

25th meeting of WG-F, Dakar, Senegal 10 – 14 October 2011

Agenda Item 6: / Any Other Business

Development of Command and Non-Payload Communications Systems

for Unmanned Aircraft Systems

(Presented by Robert J. Kerczewski, U.S. National Aeronautics and Space Administration)

SUMMARY
The US National Aeronautics and Space Administration (NASA) has initiated a project called Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS). The mission of this research project is to: “Utilize integrated system level tests in a relevant environment to reduce technical barriers related to the safety and operational challenges of UAS National Airspace System access and to work with key stakeholders to define necessary deliverables/products to help enable UAS access to the NAS.”
The Communications Subproject of the UAS in the NAS Project addresses the challenge of validating new UAS spectrum and data link communications to enable UAS integration in the NAS. The focus of this work is the establishment of standards for the Control and Non-Payload Communications (CNPC) terrestrial-based system which provides secure, scalable data communications in protected aviation safety spectrum allocation. This includes the definition of requirements, development of standards (through RTCA SC-203), and building and testing of prototype CNPC system hardware. The planned frequency bands for CNPC terrestrial system are 960-977 MHz and 5030-5091 MHz, allocations which are anticipated to be approved during WRC-12 for this purpose.
ACTION
The meeting is requested to note the progress on CNPC system development for UAS airspace integration and its dependence on the allocation of UAS CNPC frequencies at WRC-12. The support of ICAO and member states to enable advancement of UAS integration is requested.

1. Background

1.1NASA’s UAS in the NAS Project addresses the increasingly urgent need to enable routine operation of Unmanned Aircraft Systems (UAS) in the U. S. National Airspace System (NAS). The application of unmanned aircraft to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UAS to the NAS. UAS represent a new capability that will provide a variety of services in the government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized due to the lack of a common understanding of what is required to safely operate UAS in the NAS. The UAS in the NAS Project provides an opportunity to transition concepts, technology, algorithms, and knowledge to the Federal Aviation Administration (FAA) and other stakeholders to help them define the requirements, regulations, and issues for routine UAS NAS access.

The UAS in the NAS Project addresses several critical research areas needed to overcome barriers to UAS integration that fall within NASA’s organizational mission. These are indicated by the five UAS in the NAS Subprojects:

•Separation Assurance

•Human Systems Integration

•Communications

•Certification

•Integrated Test and Evaluation

Of interest in this paper is the Communications Subproject. The elements of the Subproject are described below.

2. Discussion

2.1The Communications Subproject, to be performed by NASA’s Glenn Research Center in Cleveland, Ohio, consists of the following elements:

2.1.1The Spectrum element has as its objective to develop data and rationale to obtain appropriate frequency spectrum allocations to enable the safe and efficient operation of UAS in the NAS. This is to be accomplished through participating and contributing to regulatory/standards organizations developing frequency, safety, security, and performance requirements for UAS Control and Non-Payload Communication (CNPC) systems, in partnership with other US government agencies and commercial entities within national and international spectrum/regulatory bodies. This element also provides analysis and development of communications data requirements for use in simulations, radio system design, CNPC system testing, and standardization groups, and analysis of proposed UAS control communication spectrum bands, to determine compatibility with in-band and adjacent band users.

2.1.2The Datalink element has the objective to develop and validate the candidate UAS CNPC system prototype which complies with proposed UAS international/national frequency regulations, ICAO SARPs, and RTCA MOPS/MASPS for UAS. A channel characterization campaign will be conducted to collect measurement data and analyze in detail the propagation environment within candidate CNPC spectrum bands, in order to supply data required to generate simulation models and design of communication system characteristics. The CNPC prototype will be developed to be compliant with these requirements through necessary technical analyses, simulations, and test measurements, in one or more CNPC spectrum bands. Spiral development of prototype CNPC system consisting of both ground and airborne CNPC radios will be accomplished through cooperative research agreement with an industry partner, including both laboratory and flight testing in a relevant environment. Testing will assess performance and validate and/or provide data to update proposed system requirements.

2.1.3The Security element will develop and validate candidate security requirements and standards for UAS CNPC system which comply with international/national regulations. Analysis, testing, and mitigation against security risks to the confidentiality, availability, and integrity of the integrated ATC and CNPC systems will be performed, enabling the proposal of requirements and developmentof architectures/standards to support these requirements. Proposed systems will be integrated into the CNPC system test program to validate performance in a relevant environment. The key elements of the CNPC Security research element are:

  • Threat and vulnerability assessment of RF and network systems expected to be employed in the CNPC operations
  • Risk mitigation strategy identify options for securely deploying a CNPC system
  • Prototype communications system security architecture design for CNPC
  • Prototype security architecture performance validation in a relevant environment

2.1.4The Modeling and Simulation element will perform analysis to support recommendations for integration of CNPC system and ATC communications to ensure safe and efficient operation of UAS in the NAS. CNPC system link models will be developed for all UAS classes to predict performance during all phases of flight. This activity supports the Datalink development. Regional and NAS-wide simulations will assess the performance and scalability of the CNPC system. Large scale simulations of mixed traffic will determine CNPC and ATC communication system performance impact on air traffic delays and system capacity. Simulations for satellite communications technologies for beyond line-of-sight (BLOS) UAS CNPC systems will develop data for supporting UAS spectrum requirements for WRC-16.

2.2In preparation for the launch of the UAS in the NAS Project, NASA’s Integrated Systems Research Program supported pre-project activities consisting of: an assessment and consolidation of UAS operational concepts, including NextGen; a State of the Art assessment of aeronautical communications systems; a technology gap analysis; an assessment of functional and operational data requirements; and a weather hazards analysis. Functional and operational data requirements are a key element driving CNPC system design. The requirements analysis was based on initial estimates generated by RTCA SC-203, using NATO STANAG 4586 standard. The Communications Subproject is updating the requirements document, and will continue to do so as other Subprojects identify communications requirements for the CNPC link not previously considered.

2.3The Datalink and Simulation and Modeling elements of the Communications Subproject will identify and analyze candidate technologies for application to CNPC. This will be conducted in cooperation with the Datalink industry partner, as well as RTCA SC-203 and other relevant organizations. The goal is to achieve maximum performance and efficiency of the CNPC design.

2.4On 30 September 2011, NASA entered into a Cooperative Agreement with Rockwell Collins Inc. (RCI), Government Systems Division. The agreement will develop CNPC prototype radios for testing and evaluation. NASA and RCI will jointly conduct technology assessments to determine candidate CNPC technologies. In a spiral development process, RCI will develop three prototypes designs, each of which will be laboratory tested and flight tested. The designs will operate in both 960-977 MHZ and 5030-5091 MHz bands. Designs will be adjusted between each cycle to improve performance against design requirements. Concurrently, CNPC standards will be refined through RTCA SC-203 to take into account test findings and realistic performance expectations, such that the completion of draft standards coincides with the completion of the UAS in the NAS Project.

2.5The following test cycles are planned:

2.5.1A channel characterization campaign in the 960-977 and 5030-5091 MHz bands will be conducted in the spring of 2012. Flight tests using NASA aircraft will perform channel sounding measurements of the RF propagation environment, including measurement of the environmental classifications: 1) open water, 2) flat rural, 3) hilly rural, 4) mountainous rural 5) suburban and 6) urban and 7) flat/hilly and mountainous desert. The resulting analysis of the measured data will provide accurate propagation models for simulation and analysis of the performance of candidate CNPC communications technologies.

2.5.2Laboratory and flight tests of the first prototype CNPC radios are scheduled for the spring/summer of 2013. Results of these tests will inform the design of the second prototype.

2.5.3Laboratory and flight tests of the second prototype CNPC radios are scheduled for the spring of 2014. Results of these tests will inform the design of the final prototype.

2.5.4Laboratory and flight tests of the final prototype CNPC radios are scheduled for the spring of 2015.

2.5.5Project level integrated flight tests will be conducted in the winter/spring of 2016. These tests will include the CNPC systems integrated with all other elements of the UAS in the NAS Project.

2.6Beyond Line-of-sight satellite communications for CNPC will be an analytical activity conducted by the Modeling and Simulation element. Possible aviation spectrum allocations for CNPC systems are as yet undetermined. A satellite payload for CNPC testing does not yet exist and is not yet planned. Therefore the Communications Subproject will focus its satellite communications efforts on providing technical analyses for the support of satellite communications CNPC allocations at WRC-16.

3. Proposed Action

3.1The meeting is invited to take note of the UAS in the NAS research project now being conducted by NASA. The Communications Subproject is focusing considerable effort on the development of CNPC systems and standards within the appropriate aeronautical safety communications spectrum. The approval of allocations for UAS CNPC in the 960-977 MHZ and 5030-5091 MHZ bands is anticipated, and is critical to the execution of the project. Without UAS CNPC allocations, progress towards routine UAS access to the airspace will be severely delayed. The support of ICAO and the member states for the UAS CNPC Allocations mentioned is therefore solicited.