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Proper heliostat alignment is a crucial point for the optimal operation of Solar Power Tower plants. To quantify canting errors in heliostat facets, we propose a target reflection technique that uses computer vision to overcome the limitations of existing methods. In our approach, a high-resolution camera is mounted on the back structure of a target heliostat. The reflection of the object heliostat mirrors contains the reflection of the back structure with the camera. This paper explains the 7-step methodology that ends up with the comparison of detected and modelled reflected borders. Preliminary results in a lab-scale testbed show a technique's uncertainty of around 0.2 mrad, including the experimental error associated with the manual adjustment of facets. [ABSTRACT FROM AUTHOR]

Tower solar power generation technology has been proved to be one of the most promising electricity generation alternatives with renewable resources. A reasonable aiming strategy is essential for the efficient operation of tower solar plant. Meanwhile, the real-time calculation of focusing strategy is strictly required for the changing sun angle and possible local cloud occlusion at the front end and the demand of working medium at the back end. However, It is difficult to solve the optimization problem in real time because of the high complexity of calculation. In our work, a supervised learning scheme based on data optimized by genetic algorithm (GA) is proposed. We try to use the idea of image translation to learn the aiming strategy of thousands of mirrors under different conditions. In a case study of a heliostat sector, our deep learning model can give an aiming strategy with an effect close to that of genetic algorithm in a twinkling. [ABSTRACT FROM AUTHOR]

This work describes a lab-scale testbed designed and built to assess a heliostat canting detection technique based on target reflection. The installation consists of two structures supporting; 1) target facet and camera, and 2) object facet. The testbed integrates a high-resolution camera connected to a computer to detect canting errors. Other equipment includes a laser alignment system, micrometer screws for canting adjustment, and an inclinometer for camera levelling. Additionally, the testbed incorporates a wireless camera control system to remotely adjust the camera zooming and focusing via a web interface. [ABSTRACT FROM AUTHOR]

Solar Power Tower systems use a series of tracking mirrors (heliostats) to concentrate sunlight into a central receiver. Each heliostat is composed of a series of smaller mirrors, called facets, that need to be correctly aligned to focus the beams into the receiver. A common problem associated with this technology is finding canting errors in the heliostat facets. One of the techniques proposed to overcome this problem includes using computer vision to accurately locate the facets and then using a heliostat's theoretical model to calculate the errors. This paper describes the computer vision mechanisms necessary to perform facet detection, proposing a quasi-automated process that minimizes the need for human input. Results show that the quasi-automated solution provides low errors in distance and slope with respect to a manual edge labelling. [ABSTRACT FROM AUTHOR]

This work presents an update on the progress of a heliostat field calibration system based on a central laser and camera method (CLCS). Results from indoor laboratory tests as well as an outdoor test are shown and discussed. The potential of the accuracy of the calibration method was assessed using an extended version of the Radon line detection algorithm which led to promising results. Moreover, current opinions are presented regarding ways to realise a potential deployment of a laser and camera system in a heliostat field in the future, but more work is required, especially with respect to laser safety, which is of utmost importance and by far the biggest challenge. Regarding the camera type, an image intensifier camera has the highest potential to be deployed in a future CLCS due to various advantages compared to non-intensified scientific cameras. A follow-on R&D project will be necessary to further investigate and optimise the CLCS. [ABSTRACT FROM AUTHOR]

The freedom of flight allows unmanned aircraft systems (UAS) the ability to inspect large areas without the necessity of roads or other types of infrastructure. This is a very desirable trait when several thousands of mirrors require inspection. Operational concentrating solar power plants generate regions of high solar flux. These unseen areas present potential flights hazards to the UAS. The intensity of these areas over the field needs to be understood, as well as how these affect the flight of a UAS. How much flux can a UAS endure before it fails? Understanding this will allow a safe flight path to be generated to avoid these failures. In a first experiment, a DJI Phantom 3 (painted black) was subjected to six suns total irradiance. The internal and external temperatures were logged and analyzed. No internal or external damage to the UAS was observed. [ABSTRACT FROM AUTHOR]

In the method described here, a bright star is used at night to measure the shape of heliostat reflectors in the field, at different elevation and azimuthal settings. The heliostats are oriented to direct starlight to the heliostat array receiver, and are then fixed in orietation while their aberrated and overlapping star images are translated across the receiver by Earth's rotation. At the receiver, each of a fixed line of cameras forms an image of the heliostats to be measured. The cameras use large aperture lenses and are closely spaced along a zig-zag line, turned to be perpendicular to the translation direction of the star. Exposures are repeated while the entire image star passes by, so as to fully sample the blurred star images in two dimensions. In this way, every point on the reflector surfaces of the viewed heliostats appears in one or another of the recorded images, as bright from reflected starlight. From this data the amplitude and direction of the surface slope at each of these points is computed from Snell's law, using the known positions of the star at the time of each exposure, of each camera and of each point on each heliostat. The surface shapes are then obtained by integration of the surface slopes. The total time needed to obtain a complete data set depends on the amount of surface error. For example, if the heliostats have peak-to-valley slope errors (from shape and pointing) of 4 mrad, a complete measurement of many exposures may be obtained in 1 minute, independent of heliostat field size, while the Earth rotates 4 mrad. The method will be particularly valuable for measuring heliostats whose reflector shape is actively altered throughout the day, so as to always form sharp images of the solar disc. But also for segmented reflectors of fixed shape, it will yield the detailed shapes and canting of the facets. The method has the advantage of being a null measurement – if there is no shape error, the star image is a point, and all the surfaces of all the heliostats appear in a single exposure of one camera. The method exploits modern, large CMOS imagers with very low read noise, and very fast (f/1.1), large format lenses to measure many heliostats at once. [ABSTRACT FROM AUTHOR]

In this paper, a new closed-loop control for the heliostat aiming of solar tower power plants is proposed. It is called Static Optimal Control and is based upon the ant-colony optimization meta-heuristic. The controller can increase the plant's efficiency, restrict the flux density and compensate for disturbances such as clouds. It is tested on small reference plant with a test case considering a suddenly appearing cloud disturbance. Within the test case, the controller could compensate for a mirror error which caused a drop of the relative power of around 3%. During the cloudy phase, the controller increased the relative power by 1%. The overflux condition which occurred after the cloud suddenly disappeared could be eliminated within 12 control steps. However, this number can be reduced by adjusting the controller parameters. [ABSTRACT FROM AUTHOR]

This paper summarizes findings from a small, mixed-method research study examining industry perspectives on the potential for new forms of automation to invigorate the concentrating solar power (CSP) industry. In Fall 2021, the Solar Energy Technologies Office (SETO) of the United States Department of Energy (DOE) funded Sandia National Laboratories to elicit industry stakeholder perspectives on the potential role of automated systems in CSP operations. We interviewed eleven CSP professionals from five countries, using a combination of structured and open comment response modes. Respondents indicated a preference for automated systems that support heliostat manufacturing and installation, calibration, and responsiveness to shifting weather conditions. This pilot study demonstrates the importance of engaging industry stakeholders in discussions of technology research and development, to promote adoptable, useful innovation. [ABSTRACT FROM AUTHOR]

Each solar tower power plant is designed for a pre-calculated optimal flux density distribution on the receiver. Any deviation from it has a direct impact on the component durability, energy efficiency and all downstream processes. An accurate knowledge of the current and predicted flux density is therefore essential. However, the existing measurements to obtain the flux density are either inaccurate, complicated or expensive. Moreover, to predict upcoming flux density maps, simulations are indispensable. Also, because there is still no cost-efficient way to measure heliostat surfaces on an industrial scale, these simulations neglect the individual surface errors of each heliostat and are therefore too inaccurate for a reliable prediction. We present a novel method based on artificial intelligence (AI) to include real heliostat surface errors into the flux density simulation, only by measuring the heliostats focal spot. The method needs only data generated by the already well-established camera-target heliostat calibration. Using the AI method as a supplement to this calibration, within this measurement, it is possible to simultaneously detect both main heliostat errors, the surface deformations and the misalignment. In this work, different neural network (NN) architectures are trained with artificially generated data and studied for their applicability to the described methodology. The network types used are conditioned and unconditioned generative adversarial networks (GANs) as well as neural radiance fields (NeRFs). The latter archives at best a Peak Signal to Noise Ratio (PSNR) of up to 27.8. Afterwards the network results are compared qualitatively in terms of image quality, controllability and dataset size. [ABSTRACT FROM AUTHOR]

An accurate and computationally fast ray-tracer is the key part for the simulation of the optical irradiation of a heliostat field in a solar central receiver system. Within this work we present how the ray-tracing for central receiver systems can be accelerated while obtaining highly accurate results. The runtime improvement is achieved by an enhanced blocking and shading routine and a parallelized evaluation of the ray-tracer using a graphical processing unit (GPU). Our new SunFlower GPU ray-tracer is implemented with the Monte-Carlo methodology such that direct run-time comparisons to other Monte-Carlo ray-tracers are possible. Within a case study we demonstrate that the improved and GPU-parallelized ray-tracer computes up to 99.95% accurate annual simulations of heliostat fields consisting of 8600 heliostats in less than 2.5 seconds. [ABSTRACT FROM AUTHOR]

We describe the design of a large-scale thermal desalination demonstrator unit for use in arid locations with a medium-to-high DNI. Most of thermal energy is provided by a conventional parabolic trough field, in the case of the demonstrator this being 4MWt. The desalination sub-system comprises a 3-effect MED, the first stage of which is a large 20 m diameter glass and steel-structured geodesic and transparent dome. The thermal energy is supplemented by direct sunlight transmitted through the dome and by an arc of small heliostats which focus yet more sunlight onto the dome itself. The prototype is under construction at Neom in KSA. [ABSTRACT FROM AUTHOR]

The global demand for affordable renewable energy has driven Stellenbosch University's Solar Thermal Energy Research Group (STERG) to design and construct a modular heliostat field using their HelioPod technology. The next generation heliostat field will require a wireless communication network with sufficient capacity, range, throughput, and low latencies. The purpose of this study is to evaluate the feasibility of wireless communication within a CST field by means of practical tests aimed to determine the influence of interference, dense networks, and range on the network performance. An overview of the main limiting factors for wireless communication in a CST field are discussed and the network's software and hardware design are presented. Wireless communication is found to be a feasible option within a CST plant provided that care is given to place all nodes with line of sight to the access point and all neighboring networks operate in non-overlapping frequencies. [ABSTRACT FROM AUTHOR]

In many concepts for the solar thermochemical production of fuels in a large scale, it is planned to place an array of receiver-reactors on a single solar tower. We investigate how each of these reactors needs to be operated and how the available power of the heliostat field should be distributed to the respective receiver-reactors to obtain maximum amount of solar fuel. Therefore, we developed a model for a single receiver-reactor, which is then used to analyze the single reactor operation. Based on that we present a heuristic which tries to maximize the hydrogen produced by an array of receiver-reactors for a given solar power. As our results are preliminary, we give an outlook on ongoing and future work in the end. [ABSTRACT FROM AUTHOR]

In a solar power tower plant, the role of the heliostat aiming strategy is to control the radiative flux distribution at the receiver surface to avoid thermally induced damage, while minimising spillage losses. Flux limitations arise from factors including the heat transfer fluid stability limits, and thermo-mechanical stress limits in receiver pipes. To accurately determine receiver flux distributions, ray-tracing is preferred, although it is more computationally expensive than convolution-based methods. In this study, we introduce a new parameterisation of heliostat aim-point locations that significantly reduces the number of parameters to determine. The new aiming model enables efficient use of ray-tracing to optimise the aiming strategy and, together with receiver thermal and mechanical models, is able to closely match the flux distribution to local values of allowable flux on the receiver. A reference case with a surround field and a cylindrical external receiver compatible with the Gen3 Liquid Pathway project is presented to test the capability of the method developed in this study. [ABSTRACT FROM AUTHOR]

The heliostat collector field is the front-end of large solar power tower plants. Any negative performance impacts on the collector field will propagate down the stream of subsystems, which can negatively impact energy production and financial revenues. An underperforming collector field will provide insufficient solar flux to the receiver resulting in the receiver running at below capacity and not producing the thermal energy required for thermal storage and to run the power block at optimum efficiency. It is prudent to have an optimally operating collector field especially for future Gen3+ plants. The performance of a deployed collector field can be impacted by mirror quality (surface and shape), mirror canting errors, tracking errors, and soiling. Any of these error sources can exist during installation and further degrade over time and, if left unattended, can drastically reduce the overall performance of the plant. Concentrating solar power (CSP) plant operators require information about the collector field performance to quickly respond with corrections, if needed, and maintain optimum plant performance. This type of fast response is especially critical for future Gen3+ plants, which require high collector field performance consistently. However, power tower operators have struggled with finding or developing the right tools to assess and subsequently fix canting errors on in-field heliostats efficiently and accurately. Sandia National Laboratories National Solar Thermal Test Facility (NSTTF) is developing an aerial imaging system to evaluate facet canting quality on in-situ and offline heliostats. The imaging system is mounted on an unmanned aerial system (UAS) to collect images of targets structures in reflection. Image processing on the collected images is then performed to get estimates of the heliostat canting errors. The initial work is to develop the system definition that achieves the required measurement sensitivities, which is on the order of 0.25-0.5 mrad for canting errors. The goal of the system is to measure heliostat canting errors to <0.5 mrad accuracy and provide data on multiple heliostats within a day. In this paper, the development of the system, a sensitivity analysis, and initial measurement results on two NSTTF heliostats are provided. [ABSTRACT FROM AUTHOR]

High-temperature energy conversion processes and the corresponding high surface temperatures of receivers increase thermal losses. This makes high-performance heliostats with increased optical and tracking quality interesting. Several improvement measures were investigated for the Stellio heliostat (Figure 1). Performance gains and cost effects were examined for each measure and for a combination of all measures. LCoE changes have been calculated to assess cost- effectiveness. [ABSTRACT FROM AUTHOR]

This paper examines the optimisation of a modular tower field CSP plant enabled by the use of sodium as the heat transfer fluid (HTF). It considers how the optimisation differs from a central tower field optimisation. The paper assesses the effect of the number of modular fields, field size, field aspect ratio, HTF piping optimisation, heliostat design, solar array optimisation, receiver sizing, and cleaning constraints on the whole plant operational and cost efficiency. The iterative techno-economic study has demonstrated the importance of allowing multiple aspects of component design, solar array morphology, manufacturing technique and material, manufacturing and installation cost, and efficient operations to interact fully, and the ways in which these interactions can result in accepted optimisation wisdoms being contradicted. [ABSTRACT FROM AUTHOR]

This work presents the design and analysis of the optical performance of a 3D-CPC of a 10 kWe solar micro- tower in the Sahelian zone. The tower consists of a field of 60 heliostats of 2 m2 and a receiver with a CPC of height equal to 18 m and inclined at an angle of 45 °. The CPC is dimensioned from an opening radius corresponding to the radius of concentrated solar flux of the heliostats field. This work presents on the one hand a method to model the 3D-CPC from its characteristics and on the other hand an approach to incorporate a complex geometry like the 3D-CPC in Monte Carlo ray tracer Soltrace. The simulation results show that the optical performance of the tower improves with the presence of the CPC which increases the solar flux at the receiver entrance while reducing the opening area of said receiver. The average concentration ratio of 3D-CPC is equal to 4.7. [ABSTRACT FROM AUTHOR]

Movable heliostats avoid the rail systems of rotating heliostat fields. They can be realized cost effectively by modifying low-cost carousel type heliostats. The cost for the modifications is estimated and compared to the savings resulting from the higher efficiency. [ABSTRACT FROM AUTHOR]

This project extends Sandia's experience in Light Detection And Ranging (LiDAR) to gain an understanding of the abilities and limits of using 3D laser scanning to capture the relative canting angles between heliostat mirror surfaces in 3D space to an accuracy sufficient to measure canting errors. To the authors' knowledge, this approach has never been developed or implemented for this purpose. The goal is to be able to automatically perform a 3D scan, retrieve the data, and use computational geometry and a-priori mechanical knowledge of the heliostats (facet arrangement and size) to filter and isolate the facets, and fit planar models to the facet surfaces. FARO FocusS70 laser range scanners are used, which provide a dense data coverage of the scan area in the form of a 3D point-cloud. Each point has the 3D coordinates of the surface position illuminated by the device as it scans the laser beam over an area, both in azimuth and elevation. These scans can contain millions of points in total. The initial plan was to primarily use the back side of the heliostat to capture the mirror (the back side being opaque). It was not expected to capture high-quality data from the reflective front side. The discovery that the front side did, indeed, yield surface data was surprising. This is a function of the soiling, or collected dust, on the mirror surface. Typical point counts on the mirror facets are seen to be between 10k – 100k points per facet, depending on the facet area and the scan point density. By collecting facet surface points, the data can be used to calculate an individual planar fit per facet, the normals of which correlate directly with the facet pointing angle. Comparisons with neighboring facets yield the canting angles. The process includes software which automatically: 1) controls the LiDAR scanner and downloads the resultant scan data, 2) isolates the heliostat data from the full scan, 3) filters the points associated with each individual facet, and 4) calculates the planar fit and relative canting angles for each facet. The goal of this work has been to develop this system to measure heliostat canting errors to less than 0.25 mrad accuracy, with processing time under 5 minutes per heliostat. A future goal is to place this or a comparable sensor on an autonomous platform, along with the software system, to collect and analyze heliostats in the field for tracking and canting errors in real time. This work complements Sandia's strategic thrust in autonomy for CSP collector systems. [ABSTRACT FROM AUTHOR]

FluxSPT is a software tool for the characterization of heliostat fields. A GUI-based version of this tool is available for free download, which requires the installation of Matlab Runtime, freely available too. FluxSPT generates the flux maps on central receivers from a heliostat field, considering its optical losses. The optical model is based on the convolution-projection method, previously validated by the authors. Symmetric flux distributions respect to the receiver midplane are computed using either the single or the multi-aiming strategy. For the multiaiming strategy, a single parameter (k aiming factor) is utilized to spread aimpoints and control the allowed peak flux and spillage. [ABSTRACT FROM AUTHOR]

To be able to achieve the challenging cost targets for heliostat fields, several innovations in detail for a carousel type heliostat were developed. The resulting cost reduction and local content are estimated. First conclusions from a Moroccan-German project that aims to increase the local added value of heliostat production are drawn. [ABSTRACT FROM AUTHOR]

The main idea of this contribution is to replace typical steel structures for heliostats by means of concrete due to its low costs. With respect to accuracy demands, a high-performance concrete is used that possesses high compressive and tensile strengths. The collector is designed as a strut-like structure with main radial beams and a central mount to ensure high stiffness. The design exhibits a circular shape to reduce shading. For construction, the concrete collector is dissolved into equal modules derived from symmetry reduction methods enabling a serial production. To show the feasibility, a small-scale prototype with a diameter of 3.2 m and a mirror area of 8 m² is developed that will be built up and qualified at the solar power tower Jülich, Germany. It consists of 4 modules and exhibits a weight of 341 kg. [ABSTRACT FROM AUTHOR]

The Solar-Institut Jülich (SIJ) and the companies Hilger GmbH and Heliokon GmbH from Germany have developed a small-scale cost-effective heliostat, called "micro heliostat". Micro heliostats can be deployed in small-scale concentrated solar power (CSP) plants to concentrate the sun's radiation for electricity generation, space or domestic water heating or industrial process heat. In contrast to conventional heliostats, the special feature of a micro heliostat is that it consists of dozens of parallel-moving, interconnected, rotatable mirror facets. The mirror facets array is fixed inside a box-shaped module and is protected from weathering and wind forces by a transparent glass cover. The choice of the building materials for the box, tracking mechanism and mirrors is largely dependent on the selected production process and the intended application of the micro heliostat. Special attention was paid to the material of the tracking mechanism as this has a direct influence on the accuracy of the micro heliostat. The choice of materials for the mirror support structure and the tracking mechanism is made in favor of plastic molded parts. A qualification assessment method has been developed by the SIJ in which a 3D laser scanner is used in combination with a coordinate measuring machine (CMM). For the validation of this assessment method, a single mirror facet was scanned and the slope deviation was computed. [ABSTRACT FROM AUTHOR]

Small heliostats tend to produce a sharp peak flux on a receiver aperture if they are all aimed at a single point. Several receiver concepts have circular receiver apertures and polar heliostat fields. It is of interest to flatten the flux distribution on such receivers to achieve a more homogeneous receiver surface temperature for improved thermal absorption and reduced thermal stress. A new implementation of an existing aiming strategy methodology is presented in this paper for a circular receiver with a polar heliostat field. This implementation is investigated using a convolution- projection flux modelling approach and compared with a baseline of single point aiming. The aiming strategy implementation reduces the peak flux magnitude from single point aiming by 66% and leads to a substantially uniform flux distribution on the aperture while incurring a 17.1% lower field optical efficiency on an aperture with a diameter of 1 m. The optical efficiency cost can be improved to a reduction (from single point aiming) of only 2% by slightly extending the aperture diameter for the same aiming points. The implementation deterministically arranges the aiming points of the heliostats to produce a flux distribution that is robust to a changing field optical efficiency distribution with solar time. [ABSTRACT FROM AUTHOR]

This paper investigates a stowing strategy of a heliostat field based on wind speed and direction, in terms of the potential benefit of additional energy collection through the partial stowing of heliostats within an azimuth angle range with reduced operating wind loads. Correlations of one-minute wind speed and DNI at a heliostat field site with the operating wind loads, based on the azimuth-elevation tracking angles of individual heliostats, were used to assess the increased operating time and collected thermal energy by the field. The results show that more than 23% of heliostats in the sector of the field with operating wind loads that are smaller than 50% of the stow loads can continue to operate during a high-wind period (e.g. 10 m/s). Adopting a stow strategy based on wind direction can increase the annual operating time of the heliostat field by 6% with increasing stow design wind speed from 6 m/s to 12 m/s. Furthermore, the stowing strategy based on wind direction to allow heliostats to continue to operate at wind speeds exceeding 10 m/s can achieve an additional 280 MWh of thermal energy collected by the heliostat field operation during time periods that would conventionally stow the entire field with 24 GWh of annual thermal energy captured. [ABSTRACT FROM AUTHOR]

This work reports two projection methods for the calculation of shadowing and blocking in the surrounding heliostat field of a Solar Tower Plant. The first one is the classical parallel projection which is widely used in the literature. The second one is the oblique projection which has been barely addressed in the literature. For the same solar altitude, the frames of two adjacent heliostats are not parallel in reality, and consequently, the projection of the shadowing and blocking areas is not parallel. Compared with raytracing methods, these two projection methods have been developed to reduce the computational cost without affecting efficiency accuracy. Therefore, they are suitable for heliostat field optimization. We have chosen a case study presented by Collado1, that used parallel projection in the calculations. Differences between parallel and oblique approaches are shown. Shading and blocking factors by the more accurate oblique projection are compared with the parallel one. The maximum difference is 0.09% and 1.44%, respectively for parallel and oblique projection in calculating the shading and blocking factor of a circular field of 4550 heliostats. [ABSTRACT FROM AUTHOR]

We describe a technology that uses a computer-driven, active servo control to change the shape of a heliostat reflector, in order to keep an image of the solar disc focused on a fixed distant target. The heliostat reflector is made with glass mirrors bent and rigidly attached to a support frame to form an initial specific concave toroidal shape. The different toroidal shapes needed throughout the day to maintain focus, despite the changing angle of the sun, are obtained by bending the frame by means of a truss of stiffening struts behind it. The struts are connected in pairs to a central back structural node, which incorporates linear actuators to change the truss geometry. For a hexagonal reflector, a total of three linear actuators suffice to adjust the amplitudes of the three lowest order orthogonal bending modes of the frame, and thereby to obtain all the different toroidal shapes needed for accurate imaging through the day. A recently constructed 1.6 m2 hexagonal prototype with three actuators has demonstrated this concept by producing sharp solar images throughout the day at a 40 m distant target. The measured flux concentration ranges from 90% to 98% into a square target measuring only 1.44 times the ideal disc diameter. Active heliostats of this type open new possibilities for nighttime solar electricity generation and solar industrial process heat, allowing fields of even relatively small numbers of heliostats to generate higher than current concentrations, as needed for high temperatures and more efficient energy conversion. A design for a scaled up hexagonal heliostat with 48 m2 reflector surface with eight petal mirror segments has been optimized using ANSYS. A 440 m diameter field of 776 of these heliostats would yield 25 MWth at 1,500x concentration by area, averaged over a cylindrical central receiver 2.75 m in height and diameter. [ABSTRACT FROM AUTHOR]

This work presents the current state of progress of a heliostat field calibration system based on a central laser and camera method. The method foresees that a laser beam is emitted onto a facet of a heliostat, which reflects the beam into the sky. Upon traversing the sky, light is scattered away from the beam. Two cameras take an image of the beam from two different angles such that a 3-D vector and from that the normal vector of the mirror facet can be computed. First indoor tests were carried out with an ultraviolet (UV) Q-switched pulsed laser with central wavelength of 355 nm that was specially modified and features a beam diameter of 47 mm. Two types of cameras were tested to take the image of the laser beam. Topics that include the laser type and wavelength, laser safety, atmospheric extinction, camera and lens technology as well as options of ultra-narrow bandpass filters had to be scrutinised and technology carefully matched. An insight into the most significant topics and theory as well as the validation of the theory is given in the following chapters. [ABSTRACT FROM AUTHOR]