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Main aim of this research was to apply multiple approaches for the development of time delay functions on three highways in Bahrain, namely; Dry Dock Highway, Arad Highway and Zallaq Highway. Four equations were obtained from previous studies and two equations were, additionally, tailored for each of the three highways. The results were used to obtain two parameters that aid in design, optimum flow rate and level of service.

Combining the drilling method with the digital image correlation (DIC) method is becoming more common to speed up the measurement and evaluate the strains relieved at several locations. However, to obtain the most accurate results, it is necessary to be aware of the influence of possible aspects that could adversely affect the results of the strain/stress analysis carried out using DIC. The paper describes several analyses to assess the influence of the 3D DIC system's calibration procedure for strain/stress analysis of the specimen with a hole loaded with four different levels of tensile force. In addition, the paper also deals with the analysis of the influence of the image brightness, which was modified by changing the exposure time of the cameras. Based on the results of strain/stress analyses performed on small areas (approx. 25 × 25 mm) of a specimen with a hole by a stereo-camera DIC system, it can be concluded that both analysed factors can negatively influence the results. The most accurate results are ensured using the calibration target of very high manufacturing precision sized similarly to the field of view observed in correlation mode. The optimal image brightness is adjusted when the mean grey value of the image is from the range of 56 up to 171 with as evenly distributed image point intensities as possible. [ABSTRACT FROM AUTHOR]

The article presents the results of applying the HBV-light model for 6 mountain rivers flowing into the Buktyrma reservoir: Buktyrma, Ulken Boken, Naryn, Kurshim, Turgysyn, Kalzhyr. Research work carried out the simulation of the flow of mountain river basins with a catchment area varying within 758-12423 km2. The parameters of the models were calibrated using the GAP optimization algorithm for the periods 1978-2017. The calibration period according to the recommendations for river basins were 5 years, with the exception of the Turgysyn and Kalzhyr river basins, where hydrological stations were opened in 2012 and 2007, respectively. For modeling the runoff as input hydrological and meteorological data were used data from the observation network of the RSE "Kazhydromet". It should be noted that, due to the sparse network of meteorological stations, for Turgysyn, Kurshim, Ulken Boken, Naryn river basins as input data were used meteorological data from stations not located in the catchment areas of rivers. As a result of model calibration, the optimal parameters for each river are obtained. Several widely used criteria were used to evaluate the effectiveness of the model: NSW, PBIAS, RSR and R2. The results of calculations of these criteria correspond to a "very good" and "good" assessment of the performance rating: the Nash-Sutcliffe criterion varying between 0.84 - 0.92, the RSR ranges 0.32-0.45, the PBIAS -14.3 % to +18.2 %. According to the simulation results, it was revealed that the model for all the rivers under consideration reproduces the dates well the beginning, duration of the spring flood period and the maximum water consumption for this period. Given the sparse network of meteorological stations and the overregulation of some river basins, the using of the HBV-light model showed good results of modeling runoff for mountain rivers of Kazakhstan for calibration period. Also, the model was validated for 2018-2020 period. Validation results on performance criteria indicators for the Buktyrma and Ulken Boken river basins showed a "very good" replication result, while for the remaining 4 river basins the results were unsatisfactory, which was a consequence of management activities on the flow of river basins. [ABSTRACT FROM AUTHOR]

Introduction. Systematic errors of microelectromechanical (MEMS) inertial sensors, such as those related to zero drift, scale factor, and nonorthogonality of sensitive axes, are the main sources of errors in strapdown inertial navigation systems (SINS). Uncompensated sensor errors accumulate over time as motion state errors, thus reducing the overall accuracy of SINS. Consequently, calibration of inertial sensors is a relevant research task. The disadvantage of existing sensor calibration methods consists in a strict requirement for the initial alignment of sensitive sensor axes relative to a reference coordinate system, which complicates the entire process of calibration. Therefore, alternative methods for MEMS sensor calibration should be developed.Aim. To develop a calibration algorithm for microelectromechanical (MEMS) sensors, which allows calibrating sensors regardless of the angular orientation of the sensor axes relative to a reference coordinate system at the initial installation, as well as to simplify the design of testing tools.Materials and methods. Publications in national and international journals on the theory of calibration of inertial sensors were reviewed. A calibration algorithm was developed based on the least squares method.Results. An algorithm for determining the calibration parameters of sensors regardless of the initial alignment of the sensor sensitive axes relative to a reference system was developed. A simple alternative design for testing MEMS sensors was proposed.Conclusion. The method of calibrating MEMS inertial sensors proposed in this work differs from conventional calibration methods by increased reliability of the results and a simplified design of testing tools. Importantly, the results of determining the calibration coefficients of a micromechanical accelerometer (MMA) do not depend on its angular position relative to a geographic coordinate system (GСS). This works contributes to improving the accuracy of SINS based on MEMS inertial sensors.

Due to differences in the properties of composition materials and construction techniques, unreinforced masonry is characterized by low strength, anisotropy, nonuniformity, and low ductility. In order to accurately simulate the mechanical behavior of unreinforced brick masonry walls under static and dynamic loads, a new elastoplastic damage constitutive model was proposed and the corresponding subroutine was developed based on the concrete material constitutive model. In the proposed constitutive model, the Rankine strength theory and the Drucker-Prager strength theory were used to define the tensile and compressive yield surface function of materials, respectively. Moreover, the stress updating algorithm was modified to consider the tensile plastic permanent deformation of masonry materials. To verify the accuracy of the proposed constitutive model, numerical simulations of the brick masonry under monotonic and cyclic uniaxial tension and compression loads were carried out. Comparisons among the numerical and theoretical and experimental results show that the proposed model can properly reflect the masonry material mechanical properties. Furthermore, the numerical models of four pieces of masonry walls with different mortar strengths were established. Low cyclic loadings were applied and the results show that the proposed constitutive model can properly simulate the wall shear failure characteristics, and the force-displacement hysteretic curves obtained by numerical simulation are in good agreement with the tests. Overall, the proposed elastic-plastic damage constitutive model can simulate the nonlinear behavior of unreinforced brick masonry walls very well, and can be used to predict the structural response of masonry walls. [ABSTRACT FROM AUTHOR]

Combining the drilling method with the digital image correlation (DIC) method is becoming more common to speed up the measurement and evaluate the strains relieved at several locations. However, to obtain the most accurate results, it is necessary to be aware of the influence of possible aspects that could adversely affect the results of the strain/stress analysis carried out using DIC. The paper describes several analyses to assess the influence of the 3D DIC system’s calibration procedure for strain/stress analysis of the specimen with a hole loaded with four different levels of tensile force. In addition, the paper also deals with the analysis of the influence of the image brightness, which was modified by changing the exposure time of the cameras. Based on the results of strain/stress analyses performed on small areas (approx. 25 × 25 mm) of a specimen with a hole by a stereo-camera DIC system, it can be concluded that both analysed factors can negatively influence the results. The most accurate results are ensured using the calibration target of very high manufacturing precision sized similarly to the field of view observed in correlation mode. The optimal image brightness is adjusted when the mean grey value of the image is from the range of 56 up to 171 with as evenly distributed image point intensities as possible.

This paper presents the longitudinal modeling of a 4-wheel traction vehicle represented in a block diagram using Matlab®/Simulink® software. The proposed modeling is suitable to be implemented in automatic parallel, oblique, or perpendicular parking systems considering speed cases between 5 km/h and 30 km/h. For the computational simulations, it was considered that the vehicle starts at rest and goes up a referenced or determined slope in degrees (°), with a sufficient rear reaction force to allow the vehicle to move until the engine produces sufficient torque. For the model of the tire variant, the magic formula (characterized by the sum of five vectors about an axis) was used. Three input signals were considered, slope, wind, and accelerator variation were considered in numerical simulations. The output signals are rear and normal front forces, vehicle speed, angular velocity, and engine acceleration. The longitudinal modeling proposed allows for easily reproducing the results and assigning new parameters to validate a Project, contributing positively both to the automotive industries and in innovation-based scientific research. [ABSTRACT FROM AUTHOR]

Low Earth Orbit (LEO) satellites have been widely used in scientific fields or commercial applications in recent decades. The demands of the real time scientific research or real time applications require real time precise LEO orbits. Usually, the predicted orbit is one of the solutions for real time users, so it is of great importance to investigate LEO orbit prediction for users who need real time LEO orbits. The centimeter level precision orbit is needed for high precision applications. Aiming at obtaining the predicted LEO orbit with centimeter precision, this article demonstrates the traditional method to conduct orbit prediction and put forward an idea of LEO orbit prediction by using onboard accelerometer data for real time applications. The procedure of LEO orbit prediction is proposed after comparing three different estimation strategies of retrieving initial conditions and dynamic parameters. Three strategies are estimating empirical coefficients every one cycle per revolution, which is the traditional method, estimating calibration parameters of one bias of accelerometer hourly for each direction by using accelerometer data, and estimating calibration parameters of one bias and one scale factor of the accelerometer for each direction with one arc by using accelerometer data. The results show that the predicted LEO orbit precision by using the traditional method can reach 10 cm when the predicted time is shorter than 20 min, while the predicted LEO orbit with better than 5 cm for each orbit direction can be achieved with accelerometer data even to predict one hour.

Calibration of Microelectromechanical (MEMS) Inertial Measurement Units (IMUs) is required to obtain a reliable measurement due to environmental and instrumental errors. Positioning systems are widely applied to inertial sensors calibration and testing. The most commonly used systems include nonmagnetic turntables, nonmagnetic rotating platforms, or robotic arms. Robotic arms provide a fast and accurate sensor positioning, but some aspects such as high-cost, non-portability, construction features, and kinematic should be considered. This paper presents a novel low-cost platform to estimate the calibration parameters of a MEMS magnetometer and accelerometer. The platform is based on a robotic arm of three degrees of freedom (DoF) using standard low-power servomotors with affordable prices and readily available. The kinematic model of the robotic arm is represented using a Denavit-Hartenberg parameters. The platform is placed in different positions to collect a dataset of points evenly distributed. The replicable design of the platform is described and the estimation of calibration parameters is developed to validate the functionality of the platform. [ABSTRACT FROM AUTHOR]

This study aims to propose and describe a procedure for calibrating the “vision subsystem” of digital optical machines, based on the affine camera model, valid for telecentric optical equipment. From this procedure, it is possible to systematise the calculation of the uncertainty of the calibration parameters associated with the “vision subsystem” by using the Monte Carlo method. The identification and characterisation of the calibration parameters of the “vision subsystem” and its associated uncertainty, obtained through this study, make it possible to characterise the metrological properties of the indicated optical equipment and ensure the metrological traceability of the measurements that have been subsequently taken. This work is divided into two parts. Part I focuses on developing a mathematical model of the “vision subsystem” and calculating the uncertainties of its parameters. Part II develops an example of measuring and calculating measurement uncertainty, based on the theoretical development of Part I. [ABSTRACT FROM AUTHOR]

An approach, able to easily and effectively integrate field measured data in whole building energy simulation (BES) models is crucial to increase simulation accuracy for existing buildings. In this paper, the robustness of a linear regression method for extracting transmission losses above ground (including air leakage) and ground heat loss parameters are analyzed. The regression method is evaluated on two documented and monitored multifamily buildings with mechanical supply and exhaust ventilation systems, with and without heat recovery. The obtained results are found to be robust, with variations less than 2% in the extracted estimates of transmission losses above ground (including air leakage) and with a high goodness of fit ( R 2 > 0.96) against measured data from two years. In addition, the estimations of the buildings ground heat loss were in good agreement with calculations in accordance with EN ISO 13370:2007. The high quality output from the used regression method serves as good prerequisites for the method to be used in conjunction with BES models to aid the analyst in a BES calibration process. [ABSTRACT FROM AUTHOR]

Real-time photogrammetry is used for the registration and control of object structure and deformations, registration of dynamic processes, particularly, in the architectural heritage objects. The main product of the photogrammetry is a three-dimensional (3D) data -- real world vision at the time the images are acquired with fixed viewing angles. In order to achieve this result a lot of digital photogrammetric workstations (DPW) were designed. A wide range of digital imagery such as scanned aerial film frames, images from digital aerial cameras as well as images from various satellite sensors could be processed using DPW. The requirements of processing, the algorithms of the photogrammetric software systems for the dynamic line-by-line acquisition processing of digital images in the photogrammetric way differ according to the applications. Therefore, it is important to test the capabilities and data accuracy of more than one digital photogrammetric system. The images of the research object were taken by a digital non- metric camera Canon EOS 1D Mark III. The quality of images depends on the camera optical system errors (calibration parameters) and camera stability - dynamic movements during images exposure. Thus, it is necessary to test calibration results and camera positions during the image exposure time. In this case, the camera was recalibrated and the new calibration parameters were checked during the images processing. Values that define camera stability and dynamics were determined. Close-range digital images were processed -- the triangulation procedure was accomplished by using digital photogrammetric software PhotoMod and Inpho as well as DPW system Bluh. The accuracy of triangulation has been tested and compared with the manufacturer's software. [ABSTRACT FROM AUTHOR]

Due to their complex nature, river models require extensive calibration in order to achieve reliable model predictions. Manually fitting the numerous parameters included in this procedure can be a laborious and repetitive process. This paper presents a new instrument, developed specifically for the automatic calibration of river models based on the software MHYSER. The instrument is completely autonomous and returns the model with the parameter values giving rise to the smallest difference between the model-generated observations and the measured observations. It utilises the software PEST to fit continuous calibration parameters and exceeds the program’s capabilities in order to also fit discontinuous calibration parameters. Testing of the instrument is accomplished using three models, one of which was developed during a study on the dynamics of sediments on the Romaine River, situated in the Eastern region of the Province of Quebec. [ABSTRACT FROM AUTHOR]

The resultant calibration parameter values and simulation accuracy of hydrologic models such as the 2005 Soil and Water Assessment Tool (SWAT2005) depend on how well spatial input parameters describe the characteristics of the study area. The objectives of this study were to (1) investigate the effect of soils dataset resolution (State Soil Geographic Database and Soil Survey Geogmphic Database) on SWAT2005 streamfiow simulation performance and calibration parameters using four precipitation datasets and (2) determine the best combination of soil and precipitation datasets for the Cobb Creek, Lake Creek, and Willow Creek subwatersheds within the Fort Cobb ReservoirExperimental watershed, Oklahoma. SWAT2005 was calibrated and validated for streamfiow for the three subwatersheds using the State Soil Geographic Database and the Soil Survey Geographic Database for each of the four available precipitation datasets with different spatial resolutions. The four sources of rainfall data included the National Weather Service's network of Cooperative Observer Program weather stations, statewide Oklahoma Mesonet, USDA Agricultural Research Service's weather station network (MICRONET), and National Weather Service Next Generation Radar (NEXRAD) precipitation estimates.The model performance was assessed using the Nasb-Sutcliffe efficiency coefficient and percent bias statistics. During both the calibration and validation periods, there were no significant differences in the model monthly performance statistics between the higher resolution Soil Survey Geographic Database and the lower resolution State Soil Geographic Database across subwatersheds, irrespective of the rainfall dataset used. However, the model performed better when the NEXRAD and MICRONET precipitation datasets were used. There were slight to large differences in the resultant calibration parameter values depending on the calibration parameter, the precipitation data used, and the subwatershed. Large differences in the simulated surface runoff and deep aquifer recharge due to soils dataset resolution could lead to significant differences in the simulated water quality components such as sediments and nutrients. This is important because significant differences in simulated sediments and/or nutrients could lead to significantly different outcomes in terms of the impacts of a given conservation practice for studies like the Conservation Effects Assessment Project. Due to the lack of measured data to validate the simulated water balance components, it was recommended to use both the fine and coarse resolution soil datasets in combination with the finer spatial resolution precipitation datasets and the simulated water balance components of interest reported as a range. [ABSTRACT FROM AUTHOR]

• A plasticity based constitutive model for ultra high toughness cementitious composites under projectile impact and blast loads is proposed. • Dynamic tensile and compressive properties are treated separately with continues transitions. • Advanced performances of the new model over existing models are proved by single element tests. • Material resistance and failures are well predicted under penetration and contact blast scenarios. Ultra high toughness cementitious composites (UHTCC) have a wide range of application prospects in various protective structures. At present, various concrete material models have been frequently used to simulate the mechanical response of such materials subjected to high-speed impact and explosive loads. However, none of these models can accurately describe the tensile ductility, strain rate effect, and shear expansion effect of UHTCC, which may lead to inaccurate numerical simulation results. In this study, a dynamic constitutive model of UHTCC was established, which comprehensively considered damage evolution, shear expansion, strain rate, strain hardening and strain softening of such materials. It was implemented into LS-DYNA software through a user-defined interface. Then comprehensive element tests were conducted and compared with the commonly used concrete models. Finally, a set of experimental tests of the UHTCC subjected to high-speed impact and contact blast loads were simulated. It was found that the numerical prediction results were in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The theory for the current-sensing electromagnetic flowmeter was newly developed. The current-sensing flowmeter can achieve the measurement with a high temporal resolution so that it can be applied to measure the flows with fast transients like two-phase flow. The signal prediction and the calibration of the current-sensing flowmeter in simplified two-phase flow were conducted, and the given calibration process would be an important step toward the calibration for real two-phase flow. The three-dimensional virtual potential distributions for the electrodes of finite size were computed for single-phase flow, annular flow, and modeled slug flow. With the gradient of the virtual potential, weight functions related to each flow pattern were deduced. A flow pattern coefficient f was introduced to simplify the calibration process for two-phase flow and measured with the impedance spectroscopy method. In order to measure the local mean velocity of a developing flow using the electromagnetic flowmeter, a localization parameter χ was modeled and compared with experimental data. [ABSTRACT FROM AUTHOR]

There have been relatively little works to shed light on the effects of errors in the intrinsic parameters on motion estimation and scene reconstruction. Given that the estimation of the extrinsic and intrinsic parameters apts to be imprecise, it is important to study the resulting distortion on the recovered structure. By making use of the iso-distortion framework, we explicitly characterize the geometry of the distorted space recovered from 3D motion with freely varying focal length. This characterization allows us: (1) to investigate the effectiveness of the visibility constraint in disambiguating errors in calibration parameters by studying the negative distortion regions and (2) to make explicit those ambiguous error situations under which the visibility constraint is not effective. An important finding is that under these ambiguous situations, the direction of heading can be accurately recovered and the structure recovered experienced a well-behaved distortion. The distortion is given by a relief transformation which preserves ordinal depth relations. Thus in the case where the change in focal length is not well estimated, structure information in the form of depth relief can be obtained. Experiments were presented to support the use of the visibility constraint in obtaining such partial motion and structure solutions. [Copyright &y& Elsevier]

A method is reported for verifying and controlling the accuracy of the calibration parameters, operating in image acquisition, for drop and bubble shape-analysis tensiometry. An error, impartially affecting the calibration parameters of both Cartesian axes, results in a squared error for the determined surface tension. Moreover, in the case where the calibration factors are affected by different errors, the determined value of surface tension is definitely unreliable, depending on the drop (or bubble) size and showing spurious in-phase or out-of-phase alterations. A procedure is illustrated for correcting the calibration parameters, on the basis of the observed results for a reference liquid. Method and procedure are validated by numerical examples. [Copyright &y& Elsevier]

An account is given of the use of RP-HPLC (reverse-phase high performance liquid chromatography) analysis of high purity chlorophylls and carotenoids standards originating from reference phytoplankton monocultures. All important chromatography parameters were established: retention time, detection limit, spectrum, wavelength of maximum absorption, calibration curve, response factors. Data were also obtained for pigment mixtures in naturalphytoplankton populations in Spitsbergen and the Gulf of Gdańsk. The identity and purity of all pigments were confirmed by co-elution with standards, including canthaxanthin as an internal standard. The data presented enable the qualitative and quantitative analysis of naturally existing phytoplankton pigments at concentrations down to 0.1 μg L-1 to be carried out without the need for standards from commercial sources. [ABSTRACT FROM AUTHOR]

• A phenomenological failure criterion, which attempts to achieve a tradeoff between simplicity and prediction quality, is developed to predict the fracture behavior of ship structures under quasi-static impact loads. • The performance of the newly developed failure criterion is evaluated by making comparisons with a series of quasi-static impact tests. • Comparisons among different failure criteria are carried out, and the performance of these criteria in terms of dissipated energy is discussed in detail. A phenomenological failure criterion, which attempts to achieve a tradeoff between simplicity and prediction quality, is developed to predict the fracture behavior of ship structures under quasi-static impact loads. For simplicity, only the dominant physical mechanism remains in the model. In high stress triaxiality regime, it is believed that ductile fracture is mainly influenced by the stress triaxiality, while under low stress triaxiality regime, Lode angle is considered as the key factor in the fracture prediction. Thus, the combined maximum shear stress and Rice Tracey (MSSRT) criterion is developed to cover a wide range of stress states. The calibration parameters in the criterion can be determined from the uniaxial tensile test only, which is suitable for industrial application where available material data are limited. Along with the fracture scaling framework, the developed failure criterion is implemented into the explicit finite element code LS-DYNA, and the performance of the failure criterion is evaluated by making comparisons with a series of indentation tests involving different materials, structural arrangements and indenter sizes. It is shown that the fracture behavior is well predicted by simulations for all cases. Besides, comparisons among different failure criteria are also carried out. It is found that MSSRT criterion could generate more consistent results when compared with other commonly used failure criteria. [ABSTRACT FROM AUTHOR]

We propose a method for implementing a high-level interface for the synthesis and animation of animated virtual faces that is in full compliance with MPEG-4 specifications. This method allows us to implement the simple facial object profile and part of the calibration facial object profile. In fact, starting from a facial wireframe and from a set of configuration files, the developed system is capable of automatically generating the animation rules suited for model animation driven by a stream of facial animation parameters. If the calibration parameters (feature points and texture) are available, the system is able to exploit this information for suitably modifying the geometry of the wireframe and for performing its animation by means of calibrated rules computed ex novo on the adapted somatics of the model. Evidence of the achievable performance is reported at the end of this paper by means of figures showing the capability of the system to reshape its geometry according to the decoded MPEG-4 facial calibration parameters and its effectiveness in performing facial expressions [ABSTRACT FROM PUBLISHER]

Low Earth Orbit (LEO) satellites have been widely used in scientific fields or commercial applications in recent decades. The demands of the real time scientific research or real time applications require real time precise LEO orbits. Usually, the predicted orbit is one of the solutions for real time users, so it is of great importance to investigate LEO orbit prediction for users who need real time LEO orbits. The centimeter level precision orbit is needed for high precision applications. Aiming at obtaining the predicted LEO orbit with centimeter precision, this article demonstrates the traditional method to conduct orbit prediction and put forward an idea of LEO orbit prediction by using onboard accelerometer data for real time applications. The procedure of LEO orbit prediction is proposed after comparing three different estimation strategies of retrieving initial conditions and dynamic parameters. Three strategies are estimating empirical coefficients every one cycle per revolution, which is the traditional method, estimating calibration parameters of one bias of accelerometer hourly for each direction by using accelerometer data, and estimating calibration parameters of one bias and one scale factor of the accelerometer for each direction with one arc by using accelerometer data. The results show that the predicted LEO orbit precision by using the traditional method can reach 10 cm when the predicted time is shorter than 20 min, while the predicted LEO orbit with better than 5 cm for each orbit direction can be achieved with accelerometer data even to predict one hour. [ABSTRACT FROM AUTHOR]

• Influence of vibration on dynamic calibration of pressure sensors is investigated. • Vibrations from the diaphragm rupture and the impact of shock wave are analyzed. • A weighted scoring method is proposed for obtaining the best calibration results. This paper devotes to investigate the influence of vibration on dynamic calibration of pressure sensors based on shock tube system. Two sensors with different types are separately calibrated under the same step pressure to distinguish the individual sensor's dependent effect. To excavate how the sensor's dynamic characteristics fluctuate under different vibration cases, support mounts and buffer rings of different materials are used in the experimental shock tube system. Vibrations from two main sources are expounded in detail and detected by an acceleration sensor installed near the pressure sensors. Based on the outputs of sensors, the influences of vibration on the repeatability, stability and dynamic characteristics of pressure sensors are analyzed qualitatively and quantitatively. Furthermore, a weighted scoring method based on the relative standard deviation of the calibration parameters is proposed to comprehensively assess the vibration effect on dynamic calibration results of pressure sensors. The experimental results show that the influence of vibration from the rupture of diaphragm on dynamic calibration can be avoided suitably by using the mount with high damping material or a shock tube with long driven section. The vibration from the instantaneous impact of shock wave has slight influence on the repeatability, rise time and resonant frequency, and significant influence on the stability, settling time, overshoot and uncertainty in working band of pressure sensors. Based on the weighted scores under different vibration cases, the combination of steel mount and aluminum ring produces the most reliable calibration result. These findings are also verified by another group of calibration experiments with a smaller amplitude of step pressure. [ABSTRACT FROM AUTHOR]

Advances in micro-electro-mechanical navigation systems and lightweight LIDAR (light detection and ranging) sensors onboard unmanned aerial vehicles (UAVs) provide the feasibility of deriving point clouds with very high and homogeneous point density. However, the deformations caused by numerous sources of errors should be carefully treated. This work presents a rigorous calibration of UAV-based LiDAR systems with refinement of the boresight angles using a point-to-plane approach. Our method is divided into a calibration and a parameter mounting refinement part. It starts with the estimation of the calibration parameters and then refines the boresight angles. The novel contribution of the paper is two-fold. First, we estimate the calibration parameters conditioning the centroid of a plane segmented to lie on its corresponding segmented plane without an additional surveying campaign. Second, we refine the boresight angles using a new point-to-plane model. The proposed method is evaluated by analyzing the accuracy assessment of the adjusted point cloud to point/planar features before and after the proposed method. Compared with the state-of-the-art method, our proposed method achieves better positional accuracy. [ABSTRACT FROM AUTHOR]