scholarly journals The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) and its operations from an unmanned aerial vehicle (UAV) during the AROMAT campaign

2018 ◽  
Vol 11 (1) ◽  
pp. 551-567 ◽  
Author(s):  
Alexis Merlaud ◽  
Frederik Tack ◽  
Daniel Constantin ◽  
Lucian Georgescu ◽  
Jeroen Maes ◽  
...  
Keyword(s):  
Water Vapour ◽  
Unmanned Aerial Vehicle ◽  
Trace Gases ◽  
Unmanned Aircraft ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Large Power ◽  
Aerial Vehicle ◽  
Composition Monitoring

Abstract. The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is a compact remote sensing instrument dedicated to mapping trace gases from an unmanned aerial vehicle (UAV). SWING is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27 cm × 12 cm × 8 cm, and 6 W. SWING was developed in parallel with a 2.5 m flying-wing UAV. This unmanned aircraft is electrically powered, has a typical airspeed of 100 km h−1, and can operate at a maximum altitude of 3 km. We present SWING-UAV experiments performed in Romania on 11 September 2014 during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign, which was dedicated to test newly developed instruments in the context of air quality satellite validation. The UAV was operated up to 700 m above ground, in the vicinity of the large power plant of Turceni (44.67∘ N, 23.41∘ E; 116 ma.s.l.). These SWING-UAV flights were coincident with another airborne experiment using the Airborne imaging differential optical absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP), and with ground-based DOAS, lidar, and balloon-borne in situ observations. The spectra recorded during the SWING-UAV flights are analysed with the DOAS technique. This analysis reveals NO2 differential slant column densities (DSCDs) up to 13±0.6×1016 molec cm−2. These NO2 DSCDs are converted to vertical column densities (VCDs) by estimating air mass factors. The resulting NO2 VCDs are up to 4.7±0.4×1016 molec cm−2. The water vapour DSCD measurements, up to 8±0.15×1022 molec cm−2, are used to estimate a volume mixing ratio of water vapour in the boundary layer of 0.013±0.002 mol mol−1. These geophysical quantities are validated with the coincident measurements.

scholarly journals The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) and its operations from an Unmanned Aerial Vehicle (UAV) during the AROMAT campaign

2017 ◽  
Author(s):  
Alexis Merlaud ◽  
Frederik Tack ◽  
Daniel Constantin ◽  
Lucian Georgescu ◽  
Jeroen Maes ◽  
...  
Keyword(s):  
Water Vapor ◽  
Unmanned Aerial Vehicle ◽  
Trace Gases ◽  
Unmanned Aircraft ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Large Power ◽  
Aerial Vehicle ◽  
Composition Monitoring

Abstract. The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is a compact remote sensing instrument dedicated to mapping trace gases from an Unmanned Aerial Vehicle (UAV). SWING is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27 x 12 x 8 cm3, and 6 W. SWING was developed in parallel with a 2.5 m flying wing UAV. This unmanned aircraft is electrically powered, has a typical airspeed of 100 km h−1, and can operate at a maximum altitude of 3 km. We present SWING-UAV experiments performed in Romania on 11 September 2014 during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign. The UAV was operated up to 700 m above ground, in the vicinity of the large power plant of Turceni (44.67° N, 23.41° E, 116 m a.s.l.). These SWING-UAV flights were coincident with another airborne experiment using the Airborne imaging Differential Optical Absorption Spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP), and with ground-based DOAS, lidar, and balloone-borne in-situ observations. The spectra recorded during the SWING-UAV flights are analyzed with the DOAS technique. This analysis reveals NO2 differential slant column densities (DSCDs) up to 13 ± 0.6 x 1016 molec cm−2. These NO2 DSCDs are converted to vertical column densities (VCDs) by estimating air mass factors. The resulting NO2 VCDs are up to 4.7 ± 0.4 x 1016 molec cm−2. The water vapor DSCD measurements, up to 8 ± 0.15 x 1022 molec cm−2, are used to estimate a volume mixing ratio of water vapor in the boundary layer of 0.013 ± 0.002 mol mol−1. These geophysical quantities are validated with the coincident measurements.

Long-term MAX-DOAS measurements of formaldehyde in the suburban area of London 

2021 ◽  
Author(s):  
Sebastian Donner ◽  
Steffen Dörner ◽  
Joelle Buxmann ◽  
Steffen Beirle ◽  
David Campbell ◽  
...  
Keyword(s):  
Trace Gases ◽  
Lower Troposphere ◽  
Anthropogenic Pollution ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Pollution Levels ◽  
Measurement Site ◽  
Prevailing Wind Direction

<p>Multi-AXis (MAX)-Differential Optical Absorption Spectroscopy (DOAS) instruments record spectra of scattered sun light under different elevation angles. From such measurements tropospheric vertical column densities (VCDs) and vertical profiles of different atmospheric trace gases and aerosols can be determined for the lower troposphere. These measurements allow a simultaneous observation of multiple trace gases, e.g. formaldehyde (HCHO), glyoxal (CHOCHO) and nitrogen dioxide (NO<sub>2</sub>), with the same measurement setup. Since November 2018, a MAX-DOAS instrument has been operating at Bayfordbury Observatory, which is located approximately 30 km north of London. This measurement site is operated by the University of Hertfordshire and equipped with an AERONET station, a LIDAR and multiple instruments to measure meteorological quantities and solar radiation. Depending on the prevailing wind direction the air masses at the measurement site can be dominated by the pollution of London (SE to SW winds) or rather pristine air (northerly winds).</p><p>First results already showed that the highest formaldehyde and glyoxal columns are observed for southerly to southeasterly winds indicating the influence of the anthropogenic emissions of London. However, the detailed patterns of the different trace gases were found to be more complex. Therefore, this measurement site is well suited to study the influence of anthropogenic pollution on the atmospheric composition and chemistry at a rather pristine location in the vicinity of London, a major European capital with about 10 million inhabitants and 4 major international airports.</p><p>In this study, trace gas and aerosol profiles are retrieved using the MAinz Profile Algorithm (MAPA) with a focus on tropospheric HCHO which plays an important role in tropospheric chemistry. The HCHO results are combined with the results of other trace species such as NO<sub>2</sub>, CHOCHO and aerosols in order to identify pollution levels, emission sources and different chemical regimes.</p>

scholarly journals Recommendations for HCHO and SO2 Retrieval Settings from MAX-DOAS Observations under Different Meteorological Conditions

2021 ◽  
Vol 13 (12) ◽  
pp. 2244
Author(s):  
Zeeshan Javed ◽  
Aimon Tanvir ◽  
Muhammad Bilal ◽  
Wenjing Su ◽  
Congzi Xia ◽  
...  
Keyword(s):  
Column Density ◽  
Trace Gases ◽  
Meteorological Conditions ◽  
Optical Absorption Spectroscopy ◽  
Chemical Production ◽  
Vertical Column ◽  
Phase Oxidation ◽  
Fog Days ◽  
Rms Errors ◽  
Optimal Settings

Recently, the occurrence of fog and haze over China has increased. The retrieval of trace gases from the multi-axis differential optical absorption spectroscopy (MAX-DOAS) is challenging under these conditions. In this study, various reported retrieval settings for formaldehyde (HCHO) and sulfur dioxide (SO2) are compared to evaluate the performance of these settings under different meteorological conditions (clear day, haze, and fog). The dataset from 1st December 2019 to 31st March 2020 over Nanjing, China, is used in this study. The results indicated that for HCHO, the optimal settings were in the 324.5–359 nm wavelength window with a polynomial order of five. At these settings, the fitting and root mean squared (RMS) errors for column density were considerably improved for haze and fog conditions, and the differential slant column densities (DSCDs) showed more accurate values compared to the DSCDs between 336.5 and 359 nm. For SO2, the optimal settings for retrieval were found to be at 307–328 nm with a polynomial order of five. Here, root mean square (RMS) and fitting errors were significantly lower under all conditions. The observed HCHO and SO2 vertical column densities were significantly lower on fog days compared to clear days, reflecting a decreased chemical production of HCHO and aqueous phase oxidation of SO2 in fog droplets.

scholarly journals Total column water vapour measurements from GOME-2 MetOp-A and MetOp-B

2014 ◽  
Vol 7 (3) ◽  
pp. 3021-3073 ◽  
Author(s):  
M. Grossi ◽  
P. Valks ◽  
D. Loyola ◽  
B. Aberle ◽  
S. Slijkhuis ◽  
...  
Keyword(s):  
Water Vapour ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Data Sets ◽  
Vertical Column ◽  
Data Set ◽  
Vertical Column Density ◽  
Data Processor ◽  
Climate Analysis ◽  
Total Column

Abstract. The knowledge of the total column water vapour (TCWV) global distribution is fundamental for climate analysis and weather monitoring. In this work, we present the retrieval algorithm used to derive the operational TCWV from the GOME-2 sensors and perform an extensive inter-comparison and validation in order to estimate their absolute accuracy and long-term stability. We use the recently reprocessed data sets retrieved by the GOME-2 instruments aboard EUMETSAT's MetOp-A and MetOp-B satellites and generated by DLR in the framework of the O3M-SAF using the GOME Data Processor (GDP) version 4.7. The retrieval algorithm is based on a classical Differential Optical Absorption Spectroscopy (DOAS) method and combines H2O/O2 retrieval for the computation of the trace gas vertical column density. We introduce a further enhancement in the quality of the H2O column by optimizing the cloud screening and developing an empirical correction in order to eliminate the instrument scan angle dependencies. We evaluate the overall consistency between about 8 months measurements from the newer GOME-2 instrument on the MetOp-B platform with the GOME-2/MetOp-A data in the overlap period. Furthermore, we compare GOME-2 results with independent TCWV data from ECMWF and with SSMIS satellite measurements during the full period January 2007–August 2013 and we perform a validation against the combined SSM/I + MERIS satellite data set developed in the framework of the ESA DUE GlobVapour project. We find global mean biases as small as ± 0.03 g cm−2 between GOME-2A and all other data sets. The combined SSM/I-MERIS sample is typically drier than the GOME-2 retrievals (−0.005 g cm−2), while on average GOME-2 data overestimate the SSMIS measurements by only 0.028 g cm−2. However, the size of some of these biases are seasonally dependent. Monthly average differences can be as large as 0.1 g cm−2, based on the analysis against SSMIS measurements, but are not as evident in the validation with the ECMWF and the SSM/I + MERIS data. Studying two exemplary months, we estimate regional differences and identify a very good agreement between GOME-2 total columns and all three independent data sets, especially for land areas, although some discrepancies over ocean and over land areas with high humidity and a relatively large surface albedo are also present.

Design and analysis of a feedback loop to regulate the basic parameters of the unmanned aircraft

2018 ◽  
Vol 92 (3) ◽  
pp. 318-328
Author(s):  
Marcin Chodnicki ◽  
Katarzyna Bartnik ◽  
Miroslaw Nowakowski ◽  
Grzegorz Kowaleczko
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Rapid Prototyping ◽  
Unmanned Aerial Vehicle ◽  
Pid Controller ◽  
Control Object ◽  
Unmanned Aircraft ◽  
Feedback Control System ◽  
Content Type ◽  
Aerial Vehicle

Purpose The motivation to perform research on feedback control system for unmanned aerial vehicles, a fact that each quadrocopter is unstable. Design/methodology/approach For this reason, it is necessary to design a control system which is capable of making unmanned aerial vehicle vertical take-off and landing (UAV VTOL) stable and controllable. For this purpose, it was decided to use a feedback control system with cascaded PID controller. The main reason for using it was that PID controllers are simple to implement and do not use much hardware resources. Moreover, cascaded control systems allow to control object response using more parameters than in a standard PID control. STM32 microcontrollers were used to make a real control system. The rapid prototyping using Embedded Coder Toolbox, FreeRTOS and STM32 CubeMX was conducted to design the algorithm of the feedback control system with cascaded PID controller for unmanned aerial vehicle vertical take-off and landings (UAV VTOLs). Findings During research, an algorithm of UAV VTOL control using the feedback control system with cascaded PID controller was designed. Tests were performed for the designed algorithm in the model simulation in Matlab/Simulink and in the real conditions. Originality/value It has been proved that an additional control loop must have a full PID controller. Moreover, a new library is presented for STM32 microcontrollers made using the Embedded Coder Toolbox just for the research. This library enabled to use rapid prototyping while developing the control algorithms.

scholarly journals Tropospheric nitrogen dioxide column retrieval from ground-based zenith–sky DOAS observations

2015 ◽  
Vol 8 (6) ◽  
pp. 2417-2435 ◽  
Author(s):  
F. Tack ◽  
F. Hendrick ◽  
F. Goutail ◽  
C. Fayt ◽  
A. Merlaud ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Measuring Instruments ◽  
Reference Spectrum ◽  
Vertical Column ◽  
Data Set ◽  
Residual Amount

Abstract. We present an algorithm for retrieving tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) from ground-based zenith–sky (ZS) measurements of scattered sunlight. The method is based on a four-step approach consisting of (1) the differential optical absorption spectroscopy (DOAS) analysis of ZS radiance spectra using a fixed reference spectrum corresponding to low NO2 absorption, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total measured slant column based on stratospheric VCDs measured at sunrise and sunset, and simulation of the rapid NO2 diurnal variation, (4) the retrieval of tropospheric VCDs by dividing the resulting tropospheric slant columns by appropriate air mass factors (AMFs). These steps are fully characterized and recommendations are given for each of them. The retrieval algorithm is applied on a ZS data set acquired with a multi-axis (MAX-) DOAS instrument during the Cabauw (51.97° N, 4.93° E, sea level) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) held from 10 June to 21 July 2009 in the Netherlands. A median value of 7.9 × 1015 molec cm−2 is found for the retrieved tropospheric NO2 VCDs, with maxima up to 6.0 × 1016 molec cm−2. The error budget assessment indicates that the overall error σTVCD on the column values is less than 28%. In the case of low tropospheric contribution, σTVCD is estimated to be around 39% and is dominated by uncertainties in the determination of the residual amount in the reference spectrum. For strong tropospheric pollution events, σTVCD drops to approximately 22% with the largest uncertainties on the determination of the stratospheric NO2 abundance and tropospheric AMFs. The tropospheric VCD amounts derived from ZS observations are compared to VCDs retrieved from off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to data from a co-located Système d'Analyse par Observations Zénithales (SAOZ) spectrometer. The retrieved tropospheric VCDs are in good agreement with the different data sets with correlation coefficients and slopes close to or larger than 0.9. The potential of the presented ZS retrieval algorithm is further demonstrated by its successful application on a 2-year data set, acquired at the NDACC (Network for the Detection of Atmospheric Composition Change) station Observatoire de Haute Provence (OHP; Southern France).

scholarly journals Issues of physical interaction of unmanned aircraft manipulators with ground objects

2018 ◽  
Vol 161 ◽  
pp. 03021 ◽  
Author(s):  
Vinh Nguyen ◽  
Oksana Solenaya ◽  
Petr Smirnov
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Flight Control ◽  
Unmanned Aircraft ◽  
Control Problems ◽  
Physical Interaction ◽  
Power Resources ◽  
The Earth ◽  
Manipulation System ◽  
Aerial Vehicle ◽  
Surrounding Space

Adding an onboard manipulation system to an unmanned aerial vehicle (UAV) significantly complicates framework, functioning algorithms, and leads to an increase in overall dimensions. The physical interaction of the manipulator with objects influences to unstabilization of UAV, which in turn leads to difficulties in positioning the UAV and reduces the accuracy of gripper motion. In addition, the physical interaction of the manipulator with objects requires increased power resources of UAVs. The article analyzes modern research of UAVs with a manipulator, including flight control problems, avoidance of contact with the earth, surrounding space, as well as manipulations with the captured object. On the basis of the analysis, a list of new problems arising in the physical interaction of UAVs with objects through an embedded manipulator is formulated.

scholarly journals Unmanned Helicopter Type Aircraft for the Pesticides and Fertilizers Application

2020 ◽  
Vol 14 (1) ◽  
pp. 61-68
Author(s):  
L. A. Marchenko ◽  
M. V. Myzin ◽  
I. V. Kuznetsov ◽  
T. V. Mochkova ◽  
A. Yu. Spiridonov
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Agricultural Land ◽  
Unmanned Aircraft ◽  
Nitrogen Fertilizers ◽  
Working Fluid ◽  
Unmanned Aerial Systems ◽  
Unmanned Helicopter ◽  
Agricultural Field ◽  
Technological Parameters ◽  
Aerial Vehicle

Digital agricultural production is based on robotic agricultural technologies for the use of pesticides and fertilizers using unmanned aerial systems, which are based on unmanned aerial vehicles for monitoring agricultural land, the pesticides application, fertilizers and other agrochemicals. (Research purpose) To develop an unmanned helicopter based aircraft for applying pesticides and fertilizers, and to substantiate its technological parameters. (Materials and methods) The authors used methodological recommendations on the use of chemicals in the precision farming system, regulatory and technical documentation for unmanned aircraft systems. (Results and discussion) The authors determined the unmanned aerial vehicle main flight technical and technological parameters for the implementation of the applying pesticides and fertilizers process. They established the dependences of its productivity on the norms of introducing working fluids of pesticides and fertilizers, the agricultural field length, and the approach distance to the field. (Conclusions) The authors developed a helicopter-type unmanned aerial vehicle of a coaxial design with a take-off mass of 280 kilograms and a payload of 50-80 kilograms, a rotor diameter of 5.3 meters, a constructive boom width with sprayers of 5 meters, a working flight height of 1-5 meters, a working speed of 40-60 kilometers per hour, the rate of working fluid of pesticides application 10-20 liters per hectare and nitrogen fertilizers 30-120 liters per hectare. They established rational values for the application rates of pesticides – 10-20 liters per hectare, the agricultural field length – at least 0.8 kilometers, ensuring maximum productivity in flight hour when processing the agricultural field. They showed that the flight distance minimizing from the runway to the field significantly increased the productivity of applying pesticides and fertilizers.

scholarly journals Technical note: Evaluation of profile retrievals of aerosols and trace gases for MAX-DOAS measurements under different aerosol scenarios based on radiative transfer simulations

2021 ◽  
Vol 21 (17) ◽  
pp. 12867-12894
Author(s):  
Xin Tian ◽  
Yang Wang ◽  
Steffen Beirle ◽  
Pinhua Xie ◽  
Thomas Wagner ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Trace Gases ◽  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Optical Absorption Spectroscopy ◽  
Limited Information ◽  
Inversion Algorithm ◽  
Vertical Column ◽  
Near Surface ◽  
Aerosol Pollution

Abstract. Ground-based Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a state-of-the-art remote sensing technique for deriving vertical profiles of trace gases and aerosols. However, MAX-DOAS profile inversions under aerosol pollution scenarios are challenging because of the complex radiative transfer and limited information content of the measurements. In this study, the performances of two inversion algorithms were evaluated for various aerosol pollution scenarios based on synthetic slant column densities (SCDs) derived from radiative transfer simulations. Compared to previous studies, in our study, much larger ranges of aerosol optical depth (AOD) and NO2 vertical column densities (VCDs) are covered. One inversion algorithm is based on optimal estimation; the other uses a parameterized approach. In this analysis, three types of profile shapes for aerosols and NO2 were considered: exponential, Boltzmann, and Gaussian. First, the systematic deviations of the retrieved aerosol profiles from the input profiles were investigated. For most cases, the AODs of the retrieved profiles were found to be systematically lower than the input values, and the deviations increased with increasing AOD. In particular for the optimal estimation algorithm and for high AOD, these findings are consistent with the results in previous studies. The assumed single scattering albedo (SSA) and asymmetry parameter (AP) have a systematic influence on the aerosol retrieval. However, for most cases the influence of the assumed SSA and AP on the retrieval results are rather small (compared to other uncertainties). For the optimal estimation algorithm, the agreement with the input values can be improved by optimizing the covariance matrix of the a priori uncertainties. Second, the aerosol effects on the NO2 profile retrieval were tested. Here, especially for the optimal estimation algorithm, a systematic dependence on the NO2 VCD was found, with a strong relative overestimation of the retrieved results for low NO2 VCDs and an underestimation for high NO2 VCDs. In contrast, the dependence on the aerosol profiles was found to be rather low. Interestingly, the results for both investigated wavelengths (360 and 477 nm) were found to be rather similar, indicating that the differences in the radiative transfer between both wavelengths have no strong effect. In general, both inversion schemes can retrieve the near-surface values of aerosol extinction and trace gas concentrations well.

scholarly journals APPROACH TO INCREASING THE SURVIVABILITY OF CLASS I UNMANNED AERIAL VEHICLE IN EMERGENCY OPERATIONS

2020 ◽  
pp. 54-63
Author(s):  
O. M. Pereguda ◽  
A. V. Rodionov ◽  
S. P. Samoilyk
Keyword(s):  
Information System ◽  
Unmanned Aerial Vehicles ◽  
Control Systems ◽  
Unmanned Aerial Vehicle ◽  
Unmanned Aircraft ◽  
Class I ◽  
Control Action ◽  
Emergency Operations ◽  
Aerial Vehicles ◽  
Aerial Vehicle

The article proposes an approach to increasing the survivability of class I unmanned aerial vehicles in emergency operations which involves development of an onboard information system for identifying emergency occasions in flight and the synthesis of a control action on the unmanned aircraft in case of hazardous factors influence. As the result of the analysis of the main trends in the development of unmanned aerial vehicles onboard control systems, it was found that the leading countries are paying significant attention to increasing their intellectualization level. This is necessary to ensure the fulfilment of complex tasks that are assigned to modern unmanned aerial vehicles in the military and civilian spheres. The main directions of such researches are identifying the problem of swarm application of unmanned aerial vehicles and expanding the capabilities of onboard control systems maintain automatically the values of certain parameters when the flight conditions changes. As the approach to increasing the survivability of a class I unmanned aerial vehicle, a vision of an onboard information system for identifying emergency occasions in flight and synthesis of control action is proposed, the functional purpose of its components is described. It is suggested that this system will be comprised of a subsystem for identifying emergency cases in flight and determining the class I unmanned aerial vehicle threat level and a subsystem for synthesizing control action. Governing documents and regulations for the state aviation of Ukraine determines the list of aircraft emergency occasions. Article mentions the necessity of detailing emergency occasions in flight, which are typical for class I unmanned aerial vehicles and an approach to their classification is proposed. A vision of the nearest partial scientific tasks and a list of expected scientific results of research in this direction are given.

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