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Small Air Transport (SAT) is emerging as suitable transportation means to allow efficient travel over a regional range, in particular for commuters, based on the use of small airports and fixed-wing aircraft with 5 to 19 seats, belonging to the EASA CS-23 category. In this framework, Clean Sky 2 Joint Undertaking, in the European Union's Horizon 2020 research and innovation program, funded the project COAST (Cost Optimized Avionics SysTem), which started in 2016 with the aim of delivering key technology enablers for the affordable cockpit and avionics, while also enabling single-pilot operations for aircraft in the SAT domain. In the project, some relevant flight management technologies to support single-pilot operations are considered, namely the ones of tactical traffic separation and enhanced situational awareness, meteorological enhanced awareness, and pilot's incapacitation emergency management. These technologies have been subject to a dedicated design and implementation process, based on an individual approach where each of them has been considered as independent and dedicated single-pilot operations enabling technology. Nevertheless, during the project execution, it emerged the opportunity to consider proper integration and enhancement of such technologies to design a unique Integrated Mission Management System (IMMS). Such IMMS technology has been considered as a potential solution to support the more effective and safe management of situations of pilot's incapacitation during the flight, under single-pilot operations, and as a relevant step forward towards more autonomous aircraft. Based on these considerations, Clean Sky supported and funded proper extension of the COAST project scope, to include the design of the additional Integrated Mission Management System. This paper, therefore, aims to outline the main concepts implemented by the baseline individual technologies (Flight Reconfiguration System, Tactical Separation System, and Advanced Weather Awareness System) already considered in the COAST project and representing the basic building blocks towards IMMS and, after that, aims to introduce the IMMS motivations and opportunities. Furthermore, the paper describes the main functionalities expected to be implemented by the Integrated Mission Management System and, finally, the expected design and implementation process.

Small Air Transport (SAT) is emerging as suitable transportation means in order to allow efficient travel over a regional range, in particular for commuters, based on the use of small airports and fixed wing aircraft with 5 to 19 seats, belonging to the EASA CS-23 category. The affordability of the SAT industry needs to be supported by the availability of new technological solutions allowing reducing the related operational costs while at the same time maintaining the required flight safety levels. In this framework, Clean Sky 2 Joint Undertaking funded the project COAST (Cost Optimized Avionics SysTem), which started in 2016 with the aim of tackling this challenge and delivering key technology enablers for the affordable cockpit and avionics, while also enabling the single pilot operations for small aircraft. The project activities cover several technologies and, among them, some selected ones, specifically addressing flight management, are considered in this paper, whose aim is the one of providing an outline of the design and implementation process status reached up to date, emphasizing the obtained results and the work to be done in the future activities expected to be performed in the project. The selected technologies here considered are the ones of tactical traffic separation and enhanced situational awareness, meteorological enhanced awareness, and pilot's incapacitation emergency management. The paper, therefore, focuses on a selected cluster, from the overall framework of the COAST project, of SAT single pilot operations enabling technologies: Tactical Separation System (TSS), Flight Reconfiguration System (FRS), and Advanced Weather Awareness System (AWAS). In the paper, a description is first reported of the overall COAST project objectives, motivations and approach to the SAT vehicles cockpit design. Then, the implemented design process is outlined and the description of each of the above-indicated selected technologies is presented (the additional technologies considered in the COAST project are out of the scope of this paper). Based on that, for each of the considered systems (TSS, FRS, AWAS) the status of the design and implementation process is described and the next steps expected to be implemented in the project are outlined.

We present a unique experimental setup that enables measurement of high-resolution complex refractive index spectra of gas sample using several cavity-enhanced methods: frequency-stabilized cavity ring-down spectroscopy, cavity mode-width spectroscopy and one-dimensional cavity mode-dispersion spectroscopy. Presented examples of applications cover molecular spectral line-shape investigations, line intensities and unperturbed line center frequency measurements and high-precision detection of systematic instrumental errors of various spectroscopic methods.

In direct frequency comb spectroscopy with a VIPA spectrometer, the resolution of the spectrometer is usually insufficient to resolve the comb modes. Thus, one can either filter the modes, reducing the density of spectral elements or cope with the inability to uniquely identify spectral elements with individual comb modes by calibrating the spectrometer itself. Here, we present a way to make use of the inherent frequency accuracy of a stabilized frequency comb to calibrate the spectrometer. We also present a comparison between two commonly used schemes to stabilize the coupling between a frequency comb and cavity resonances: the Pound-Drever-Hall locking scheme and the swept coupling scheme.

Synopsis We present precise line-shape measurements of the nitrogen-broadened P9 P9 oxygen B-band transition occurring near 689 nm. Data were obtained using the optical frequency comb-assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer. Several line-shape models describing physical effects such as Dicke narrowing, the speed dependence of collisional broadening and shifting, and the correlation between velocity- and phase-changing collisions were used in the analysis. The multispectrum fitting technique is used to minimize correlation between line-shape parameters. Observed line narrowing is mostly determined by the speed dependence of the collisional broadening.

A short review of recent achievements in high-precision cavity enhanced absorption spectroscopy is presented. Actual challenges and development paths in modern line shape study are indicated and discussed. The importance of identification and quantification of systematic instrumental errors affecting the measured line shape is highlighted. New, alternative measurement methods based on cavity enhanced spectroscopy are proposed.

We report the use of a digital lock to measure the line profile and center frequency of rubidium 5S-7S two-photon transitions with a cw laser referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm), insensitive to first-order in a magnetic field, is a promising candidate for frequency reference.

Results of line-shape measurements of self- and N2-broadened P9 P9 transition of the oxygen B band are presented. Spectra were acquired using the optical frequency comb- assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer (PDH- locked FS-CRDS). In the line-shape analysis the line narrowing described by Dicke narrowing or/and the speed dependence of collisional broadening were taken into account. The multispectrum fitting technique was used to minimize numerical correlations between line-shape parameters. Collisional broadening and shifting coefficients are reported with sub-percent uncertainties. Influence of the spectral line-shape model used in data analysis on determined line intensities and collisional broadening is discussed.

We present a proof-of-principle experiment demonstrating the use of atomic optical clocks as a frequency reference in Doppler-limited molecular spectroscopy. We report the determination of an unperturbed line position with a relative uncertainty of 2 × 10-11.

New approaches to cavity enhanced absorption spectroscopy are presented. They are based on precise measurements of shape of cavity modes broadened and shifted in the vicinity of the absorber placed inside the high-finesse cavity. The usefulness of both techniques to accurate line-shape study is demonstrated on an example of a weak (3 ← 0) 13C16O transition.