Bistatic DIAL for multi-species aviation pollutant measurements from RPAS

This paper presents the conceptual design of a new low-cost measurement system for the determination of pollutant concentrations associated with aircraft operations. The proposed system employs Light Detection and Ranging (LIDAR) and passive electro-optics equipment installed in two non-collocated components. The source component consists of a tuneable small-size and low-cost/weight LIDAR emitter, which can be installed either on airborne or ground-based autonomous vehicles, or in fixed surface installations. The sensor component includes a target surface calibrated for reflectance and passive electro-optics equipment calibrated for radiance, both installed on an adjustable support. The proposed bistatic system determines the column-averaged molecular and aerosol pollutant concentrations along the LIDAR beam by measuring the cumulative absorption and scattering phenomena along the optical slant range. The molecular column densities are measured by means of Differential Absorption LIDAR (DIAL), which exploits the known molecular vibration processes for non-ambiguous species detection. Aerosol concentrations such as particulate and soot are determined by means of knowledge-based inversion with regularization. The laboratory calibration of the system components is also discussed. Previously published uncertainty analysis results highlighted the positive qualities of the proposed measurement system even in degraded meteorological conditions, making the proposed bistatic LIDAR a viable alternative to other systems currently employed

Orbital and meteorological factors pertinent to satellite transmissions of facsimile weather charts Final report

Automatic picture transmission system on Nimbus and earth synchronous satellites for transmission of weather chart

Bistatic measurement system for characterisation of aviation pollutant concentrations

This paper presents the conceptual design of a low-cost measurement system for the dete1mination of aviation-related pollutant concentrations in dense air traffic areas. The proposed bistatic Light Detection and Ranging (LIDAR) system consists of two noncollocated components. The source component consists of a tuneable laser emitter, which can either be installed on a Remotely Piloted Aircraft System (RP AS) or operated from fixed and movable surface installations. The sensor component is constituted by a target surface calibrated for reflectance and a rail-mounted visible or infrared camera calibrated for radiance. The system perfmms Differential Absorption LIDAR (DIAL) measurements. The relevant oppo1t1mities and challenges, and the viability of the system in the intended operational environments are discussed. N1m1erical simulation results show promising perfmmances in term of error expected error budget even in degraded meteorological conditions, which are comparable to the more complex and relatively costly monostatic LIDAR techniques cmTently available

Cooperative and non-cooperative sense-and-avoid in the CNS+A context: a unified methodology

A unified approach to cooperative and noncooperative Sense-and-Avoid (SAA) is presented that addresses the technical and regulatory challenges of Unmanned Aircraft Systems (UAS) integration into nonsegregated airspace. In this paper, state-of-the-art sensor/system technologies for cooperative and noncooperative SAA are reviewed and a reference system architecture is presented. Automated selection of sensors/systems including passive and active Forward Looking Sensors (FLS), Traffic Collision Avoidance System (TCAS) and Automatic Dependent Surveillance - Broadcast (ADS-B) system is performed based on Boolean Decision Logics (BDL) to support trusted autonomous operations during all flight phases. The BDL adoption allows for a dynamic reconfiguration of the SAA architecture, based on the current error estimates of navigation and tracking sensors/systems. The significance of this approach is discussed in the Communication, Navigation and Surveillance/Air Traffic Management and Avionics (CNS+A) context, with a focus on avionics and ATM certification requirements. Additionally, the mathematical models employed in the SAA Unified Method (SUM) to compute the overall uncertainty volume in the airspace surrounding an intruder/obstacle are described. In the presented methodology, navigation and tracking errors affecting the host UAS platform and intruder sensor measurements are translated to unified range and bearing uncertainty descriptors. Simulation case studies are presented to evaluate the performance of the unified approach on a representative UAS host platform and a number of intruder platforms. The results confirm the validity of the proposed unified methodology providing a pathway for certification of SAA systems that typically employ a suite of non-cooperative sensors and/or cooperative systems

A laser obstacle warning and avoidance system for unmanned aircraft sense-and-avoid

This paper presents an overview of the research activities performed to develop a new scaled variant of the Laser Obstacle Avoidance and Monitoring (LOAM) system for small-to-medium size Unmanned Aircraft (UA) platforms. This LOAM variant (LOAM+) is proposed as one of the non-cooperative sensors employed in the UA Sense-and-Avoid (SAA) system. After a brief description of the LOAM system architecture, the mathematical models developed for obstacle avoidance and calculation of alternative flight path are presented. Additionally, a new formulation is adopted for defining the uncertainty volumes associated with the detected obstacles. Simulation case studies are carried out to evaluate the performances of the avoidance trajectory generation and optimisation algorithms, which demonstrate the ability of LOAM+ to effectively detect and avoid fixed low-level obstacles in the intended path

Bistatic LIDAR system for the characterisation of aviation-related pollutant column densities

In this paper we investigate an innovative application of Light Detection and Ranging (LIDAR) technology for aviation-related pollutant measurements. The proposed measurement technique is conceived for the high-resolution characterisation in space and time domains of aviation-related pollutant gases. The system performs Integral Path Differential Absorption (IPDA) measurement in a bistatic LIDAR measurement setup. The airborne component consists of a tuneable Near Infrared (NIR) laser emitter installed on an Unmanned Aircraft (UA) and the ground sub-system is composed by a target reference surface (calibrated for reflectance) and a differential transmittance measuring device based on a NIR Camera calibrated for radiance. The specific system implementation for Carbon Dioxide (CO2) measurement is discussed. A preliminary assessment of the error figures associated with the proposed system layout is performed

4-dimensional trajectory generation algorithms for RPAS mission management systems

This paper presents the algorithms enabling real-time 4-Dimensional Flight Trajectory (4DT) functionalities in Next Generation Mission Management Systems (NG-MMS), which are the core element of future Remotely Piloted Aircraft Systems (RPAS) avionics. In particular, the algorithms are employed for multi-objective optimisation of 4DT intents in various operational scenarios spanning from online strategic to tactical and emergency tasks. The adopted formulation of the multi-objective 4DT optimisation problem includes a number of environmental objectives and operational constraints. In particular, this paper describes the algorithm for planning of 4DT based on a multi-objective optimisation approach and the generalised expression of the cost function adopted for penalties associated with specific airspace volumes, accounting for weather, condensation trails and noise models

Multi-objective optimisation of aircraft flight trajectories in the ATM and avionics context

The continuous increase of air transport demand worldwide and the push for a more economically viable and environmentally sustainable aviation are driving significant evolutions of aircraft, airspace and airport systems design and operations. Although extensive research has been performed on the optimisation of aircraft trajectories and very efficient algorithms were widely adopted for the optimisation of vertical flight profiles, it is only in the last few years that higher levels of automation were proposed for integrated flight planning and re-routing functionalities of innovative Communication Navigation and Surveillance/Air Traffic Management (CNS/ATM) and Avionics (CNS+A) systems. In this context, the implementation of additional environmental targets and of multiple operational constraints introduces the need to efficiently deal with multiple objectives as part of the trajectory optimisation algorithm. This article provides a comprehensive review of Multi-Objective Trajectory Optimisation (MOTO) techniques for transport aircraft flight operations, with a special focus on the recent advances introduced in the CNS+A research context. In the first section, a brief introduction is given, together with an overview of the main international research initiatives where this topic has been studied, and the problem statement is provided. The second section introduces the mathematical formulation and the third section reviews the numerical solution techniques, including discretisation and optimisation methods for the specific problem formulated. The fourth section summarises the strategies to articulate the preferences and to select optimal trajectories when multiple conflicting objectives are introduced. The fifth section introduces a number of models defining the optimality criteria and constraints typically adopted in MOTO studies, including fuel consumption, air pollutant and noise emissions, operational costs, condensation trails, airspace and airport operations

The effects of tube deformities on the dynamic calibration of a tubing system

Using the Berge and Tijdemen method for tube calibration is powerful as it allows for tubes of various dimensions to be used in a dynamic pressure data acquisition system by using post-processing methods to calibrate for the tubes natural dynamic response. Knowing the tubes response and using the inverse Fourier transform to calibrate the tube system is accepted however knowing how tube deformities influence this calibration is not known. Small singular deformities caused by pinch, twist and bending, which corresponded to a pinch and internal area ratios less than approximately 5 and 3.57 respectively, do not affect the tubing response of a system. Significant effects on the tubes response only occur at pinch and area ratios above these values. Furthermore, pinching ratios above 5 are extreme and represent a tube that is pinched locally to the point where it is almost blocked. This is testament to the tubes resilience to local and internal diameter changes. It can be safely assumed that unwanted and unexpected dampening of a tubing system could be due to a local tube deformity

Reverse engineering of a fixed wing unmanned aircraft 6-DoF model based on laser scanner measurements

This paper describes a method for deriving sixdegree- of-freedom (6-DoF) aircraft dynamics parameters adopting reverse engineering techniques from three dimensional (3D) laser scanner measurements. In particular, the mass and aerodynamic properties of the JAVELIN Unmanned Aircraft (UA) are determined using accurate measurements from the 3D scanner and successive CAD processing of the geometric data. In order to qualitatively assess the calculated 6-DoF, the trajectory for the spiral mode excited by the engine torque of this UA is simulated and compared to that of a published 6-DoF of the popular AEROSONDE UA which has very similar geometry. Additionally, to further confirm the validity of the approach, the reverse engineering procedure is applied to a published CAD model of the AEROSONDE UA and the associated 6-DoF parameters are calculated. Using these parameters, a spiral descent trajectory is generated using both the published and calculated parameters. The trajectories match closely, providing a good qualitative verification of the reverse engineering method. In future research, the accurate knowledge of the 6-DoF dynamics will enable the development of an Aircraft Dynamics Model (ADM) virtual sensor to augment the UA navigation system in case of primary navigation sensor outages. Additionally, further refinement of the calculated 6-DoF will involve wind tunnel and flight testing activities