Fly by data link: feasibility of a relative navigation solution for aviation relying on a future L-band data link

Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e TelecomunicaçõesO presente trabalho estuda uma solução alternativa de navegação aeronáutica que contribua para a racionalização da infrastrutura terrestre de ajudas-rádio de navegação na Europa. O conceito designado de “Performance Based Navigation (PBN)” emerge actualmente ao nível da Organização Internacional de Aviação Civil, visando o aperfeiçoamento do sistema de gestão do tráfego aéreo ao nível da eficiência, segurançae capacidade. O conceito PBN promove a modernização da infrastrutura aeronáutica com base na utilização preferencial de sistemas de navegação por satélite, designadamente mediante o recurso a sinais disponibilizados pelas constelações “Global Navigation Satellite System (GNSS)”. Face às vulnerabilidades dos sistemas GNSS a interferências RF, “jamming” deliberado ou fenómenos solares, foi decidido manter uma infrastrutura de recurso/”backup”, para mitigar falhas GNSS, baseada numa redede rádio-ajudas terrestres “Distance Measuring Equipment (DME)”. Visto que estes DMEs não facultam uma boa cobertura, especialmente a baixa altitude, e tratando-se de equipamentos próximos da obsolescência tecnológica e pouco eficientes em termos de espectro rádioeléctrico, a sua racionalização requer uma tecnologia alternativa. O presente trabalho explora o recurso a novas tecnologias aeronáuticas de comunicações dados ar-solo, designadamente o futuro “data link” OFDM/TDMA de banda L (LDACS), verificando a sua adequação para suportarem as funções de navegação descritas substituindo os DMEs. Pretende-se confirmar a viabilidade com base no conceito de Navegação Relativa (RELNAV) usado em contexto militar recorrendo a filtros Kalman. As características da tecnologia LDACS são descritas e são apresentados resultados de testes do seu desempenho em termos de medição de distâncias (“ranging”). Com base nas capacidades RELNAV militares são propostos melhoramentos baseadosem filtros Kalman, simulando para demonstrar que o LDACS pode ser usado para funçãode navegação. Demonstrada a viabilidade, fica em aberto a oportunidade para sinergias que poderão viabilizar a racionalização da infrastrutura terrestre de navegação e aviónicos.Abstract: The main purpose of this work is to study an alternative solution for aeronautical aircraft navigation contributing to the rationalization of the existing European ground navigation infrastructure. The emerging Performance Based Navigation (PBN) concept, described in the document 9613 of the International Civil Aviation Organization (ICAO), calls for increased reliance on Global Navigation Satellite Systems (GNSS) (and its augmentation/differential correction systems1) but retaining ground beacons such as the Distance Measuring Equipments (DME) to cope with Global Positioning System (GPS) and GALILEO outages (e.g. jamming/solar storms). The present work will focus on demonstrating the feasibility of an alternative technology to allow the decommissioning of such DME beacons based on the re-use offuture L-Band Air Ground Data Link (LDACS) communication solutions being subject of research studies. Such data links may support the required levels of positioning, navigation and timing required to complement GNSS when the aircraft fly in an area navigation environment. This work will describe the LDACS data link technologies2 and will explain how such communications enablers would be able to support a “relative navigation” function similar to the one available in military data link technologies usinga geodetic grid. The feasibility of the proposed solution will be demonstrated on the basis of lessons learnt from military relative navigation and simulations which will evidence the technical performance/error parameters of the system in terms of ranging, bearing and horizontal positioning and other relevant QoS aspects. In addition, the multipath and co-site interference effects will be also discussed. Should the proposed solution be demonstrated as viable, it may open the door, not only for synergies leading to a more seamless aircraft equipage but also to the rationalization of aeronautical systems in the spectrum band 960-1215 MHz, which is highly congested and subject of stringent non-interference basis operational limitations

L-Band System Engineering - Concepts of Use, Systems Performance Requirements, and Architecture

This document is being provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-band and L-band Communications Standard Development. Task 7 was motivated by the five year technology assessment performed for the Federal Aviation Administration (FAA) under the joint FAA-EUROCONTROL cooperative research Action Plan (AP-17), also known as the Future Communications Study (FCS). It was based on direction provided by the FAA project-level agreement (PLA FY09_G1M.02-02v1) for "New ATM Requirements-Future Communications." Task 7 was separated into two distinct subtasks, each aligned with specific work elements and deliverable items. Subtask 7-1 addressed C-band airport surface data communications standards development, systems engineering, test bed development, and tests/demonstrations to establish operational capability for what is now referred to as the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2, which is the subject of this report, focused on preliminary systems engineering and support of joint FAA/EUROCONTROL development and evaluation of a future L-band (960 to 1164 MHz) air/ground (A/G) communication system known as the L-band digital aeronautical communications system (L-DACS), which was defined during the FCS. The proposed L-DACS will be capable of providing ATM services in continental airspace in the 2020+ timeframe. Subtask 7-2 was performed in two phases. Phase I featured development of Concepts of Use, high level functional analyses, performance of initial L-band system safety and security risk assessments, and development of high level requirements and architectures. It also included the aforementioned support of joint L-DACS development and evaluation, including inputs to L-DACS design specifications. Phase II provided a refinement of the systems engineering activities performed during Phase I, along with continued joint FAA/EUROCONTROL L-DACS development and evaluation support

Feasibility of the Frequency Planning for LDACS Air-to-Air Communications in the L-band

The 960-1215 MHz frequency range in the L-band is allocated worldwide on a primary basis to the aeronautical radio navigation service (ARNS). At the World Radio Conference 2007, the frequency range 960-1164 MHz within the L-band was additionally allocated to the aeronautical mobile (route) service (AM(R)S) on a co-primary basis to allow future communication systems to share large parts of the L-band with the existing radio navigation services. The L-band digital aeronautical communications system (LDACS) will operate its air-ground (A/G) and air-to-air (A2A) data links under AM(R)S allocation in the L-band ensuring spectrum sharing without mutual harmful interference. In this paper, we propose a frequency planning methodology for the LDACS A2A data link yielding no harmful interference towards the legacy systems operating in the L-band. We also assess the feasibility of the LDACS A2A frequency planning in the north-east coast of North America, the North Atlantic Corridor, and western Europe. Our results indicate that LDACS A2A can operate in the 960-1164 MHz frequency range without affecting the proper operation of the legacy systems. Whilst the available spectrum is maximized in oceanic airspace and reduced in continental airspace, LDACS A2A can employ numerous frequency channels in most locations. The lower part of the L-band presents the most promising results, as LDACS A2A can operate there in any considered location. In fact, the lowest frequencies can be used anywhere in the considered region, which might allow LDACS A2A to have a globally available frequency channel for its operation

Identification of Technologies for Provision of Future Aeronautical Communications

This report describes the process, findings, and recommendations of the second of three phases of the Future Communications Study (FCS) technology investigation conducted by NASA Glenn Research Center and ITT Advanced Engineering & Sciences Division for the Federal Aviation Administration (FAA). The FCS is a collaborative research effort between the FAA and Eurocontrol to address frequency congestion and spectrum depletion for safety critical airground communications. The goal of the technology investigation is to identify technologies that can support the longterm aeronautical mobile communication operating concept. A derived set of evaluation criteria traceable to the operating concept document is presented. An adaptation of the analytical hierarchy process is described and recommended for selecting candidates for detailed evaluation. Evaluations of a subset of technologies brought forward from the prescreening process are provided. Five of those are identified as candidates with the highest potential for continental airspace solutions in L-band (P-34, W-CDMA, LDL, B-VHF, and E-TDMA). Additional technologies are identified as best performers in the unique environments of remote/oceanic airspace in the satellite bands (Inmarsat SBB and a custom satellite solution) and the airport flight domain in C-band (802.16e). Details of the evaluation criteria, channel models, and the technology evaluations are provided in appendixes

FCS Technology Investigation Overview

This working paper provides an overview of the Future Communication Study (FCS) technology investigation progress. It includes a description of the methodology applied to technology evaluation; evaluation criteria; and technology screening (down select) results. A comparison of screening results with other similar technology screening activities is provided. Additional information included in this working paper is a description of in-depth studies (including characterization of the L-band aeronautical channel; L-band deployment cost assessment; and performance assessments of candidate technologies in the applicable aeronautical channel) that have been conducted to support technology evaluations. The paper concludes with a description on-going activities leading to conclusion of the technology investigation and the development of technology recommendations