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Ground penetrating radar has been acknowledged as an effective and efficient technique for non-destructive investigation for near-subsurface exploration that is based on the reflection receiver-transmitter of the antenna when hitting buried objects. An accurate interpretation of GPR data is greatly important in locating and mapping underground objects. Although GPR research has achieved remarkable success, the interpretation of GPR raw data highly depends on the reliance of user experts. Further, unexperienced GPR users are subject to error since the hyperbola signatures may resemble each other. Therefore, this work focuses on the development of a 3D reconstruction of the hyperbola signature of underground objects using GPR images for mapping applications. In this study, 3D reconstruction has been developed based on the Synthetic Aperture Focusing Technique, also known as SAFT. At the first stage, the raw input of GPR images was subjected to zero-time correction and background elimination. Next is the projection of each hyperbola signature by means of B-Scan images to create a 3D image. Then, the resultant 3D images were stacked together, and further 3D interpolation techniques were employed on the images. The experimental studies have been done on GPR data using a metal sphere as a sample. The findings of the study highlight that the SAFT method was able to reconstruct the 3D model of the hyperbola signature and exhibit the ability to provide clues about the location of the underground object through the representation of the voxel point of the images. Based on these results, the SAFT technique provides good insight into the 3D reconstruction of hyperbola signatures using GPR images in mapping applications. [ABSTRACT FROM AUTHOR]

The Mosul Dam project was built on weakly, unstable generational land, and when it enters into contact with the water, its properties change. As a result, excess water in several vertical apertures in the dam's body must be observed to warn against the possibility of the dam collapse. A bar scale is used to initially measure the water column depth in the dam apertures. This research proposes a new system using wireless sensors injected as a floated object on the water columns altimeter and sending the water-level values to LoRa-WAN in real-time. This study simulates a new Long Range Wide Area Network (LoRa-WAN) technology to monitor a variety of water levels in Mosul Dam, which is linked to an Internet of Things (IoT) structure that is based on wireless sensor networks (WSNs). A LoRa gateway is employed to transfer these data over it. Alerts will be transmitted by end devices and received by the LoRa WAN, showing the specific end devices position, if the water levels exceed the allowable predetermined level. The network will then take suitable measures. This paper displays a simulation software implementation omnet++ to evaluate the performance of LoRa as an outcome of implementation across the FLoRa framework to simulate monitoring the water level in Mosul Dam. The performance impact of LoRa networks was evaluated on Network Energy Consumed and Packet Delivery Ratio for (1) the number of gateways, and (2) the distance between each end device and the LoRa gateway. Our results demonstrated that optimizing the parameters that impact a LoRa network's performance can convert traditional monitoring to smart monitoring as well as the capability of one LoRa gateway to run up to (1000) end devices. [ABSTRACT FROM AUTHOR]

This paper addresses an automatic adjustment of the Chirp baseband pulse duration for synthetic aperture radar depending on the height of the aircraft that brought the sensor. With this capability, the radar sensor will automatically adjust the duration of the chirp pulse to obtain the optimal signal density in order to obtain a detailed chirp signal. This method also might ease the operation of sensing with a synthetic aperture radar (SAR) system at varying aircraft altitudes. The chirp signal is generated by the DDS method with the load of the memory look-up table using a digital-to-analog converter (DAC) resolution of 14 bit and a frequency sampling of 200 MHz. The results of the simulation tests have demonstrated that the suggested method can produce chirp signals and automatically modify the duration of chirp signals adjusted with aircraft altitude changes between 1 to 1500 meters. [ABSTRACT FROM AUTHOR]

Anak Krakatoa Volcano is a young volcano that appeared in the caldera after the proximal eruption in 1883 from the Krakatoa volcanic complex. currently, Anak Krakatoa Volcano is in the construction phase. Based on measurements by the Center for Volcanology and Geological Hazard Mitigation (PVMBG) conducted in September 2018, it was found that the elevation of the Anak Krakatoa volcano is above 338 m from sea level. From June 25, 2018, until the end of 2019 Anak Krakatoa Volcano experienced a strombolian eruption, this eruption caused deformation on the surface of the Volcano. The research used the Differential Interferometry Synthetic Aperture Radar (DInSAR) method with Sentinel-1A image data from April 2018 to December 2019 which was further validated using volcanic activity released by PVMBG. The results were obtained in the form of deformation value based on Line of Sight (LOS) displacement, and the result of deflation is 0,01 cm to 17,1 cm using cross-section in the area around the crater is deflation in June 2018 to February 2019. [ABSTRACT FROM AUTHOR]

Microwaves are usually in the range of a few to ten centimeters with the wavelengths used by remote sensing radars to monitor Earth's atmosphere. The radar pulse loses energy as they travel in the space at a rate proportional to the beamwidth. The beam spread significantly by the time it reaches the earth. Synthetic aperture radars are the solution to this problem since the outcome will greatly change. Synthetic aperture radars were designed to circumvent natural aperture radar limitations. Such systems obtain a strong azimuth resolution which is not based on the slant but does use small antennas and fairly long wavelengths. [ABSTRACT FROM AUTHOR]

This case study discusses the possibility of using satellite data, instead of ground pluviometric measurements, as input data in modeling a hydrological system. One of the biggest problems in the monitoring process is the determination of floodable areas in order to establish and assess damage and risk management. Also, the maps regarding the floods are a real help to the institutions and to those who intervene in rescuing the population. Unlike optical sensors, synthetic aperture (SAR) radar provides valid measurements by covering high-resolution clouds. [ABSTRACT FROM AUTHOR]

This case study discusses the possibility of using satellite data, instead of ground pluviometric measurements, as input data in modeling a hydrological system. One of the biggest problems in the monitoring process is the determination of floodable areas in order to establish and assess damage and risk management. Also, the maps regarding the floods are a real help to the institutions and to those who intervene in rescuing the population. Unlike optical sensors, synthetic aperture (SAR) radar provides valid measurements by covering high-resolution clouds. [ABSTRACT FROM AUTHOR]

A method of space-based interferometric synthetic aperture radar measurements (InSAR and DInSAR techniques) is designed for obtaining of different types of altitude data for the Earth surface, i.e. terrain heights and surface displacements. Phase noise is an intrinsic random uncorrelated additive process, which complicates data processing in such systems. The experimental study of the linear non-adaptive phase noise filters are studied using the previously developed technique for experimental evaluation of the InSAR processing algorithms effectiveness. The accuracy characteristics for the filters applied to ALOS PALSAR data for areas with hilly and low-mountainous terrain are obtained, and it is shown, that one of the filters gives a slight better results (with less error value) under the equal computational complexity. [ABSTRACT FROM AUTHOR]

The normal Radon transform as well as the circular Radon transform are reviewed in this work. Traditionally, the first is linked to computerized tomography and the second is linked to synthetic aperture techniques that are well-established in both, radar, and ultrasound imaging systems. A new method that adapts the ordinary algebraic reconstruction methods to numerically reconstruct an image from its circular Radon transform is presented. To this end, a representation of an image using the unit box functions is employed, this representation facilitates the formation of an exact matrix of coefficients for a linear system to be solved. Regularized least square is used to solve the relatively small systems, and a machine learning approach is used for large systems. Several experiments are conducted for validation of the built system as well the reconstruction of images from their circular Radon transform. [ABSTRACT FROM AUTHOR]

The normal Radon transform as well as the circular Radon transform are reviewed in this work. Traditionally, the first is linked to computerized tomography and the second is linked to synthetic aperture techniques that are well-established in both, radar, and ultrasound imaging systems. A new method that adapts the ordinary algebraic reconstruction methods to numerically reconstruct an image from its circular Radon transform is presented. To this end, a representation of an image using the unit box functions is employed, this representation facilitates the formation of an exact matrix of coefficients for a linear system to be solved. Regularized least square is used to solve the relatively small systems, and a machine learning approach is used for large systems. Several experiments are conducted for validation of the built system as well the reconstruction of images from their circular Radon transform. [ABSTRACT FROM AUTHOR]

Computer technique was developed to simulate basic parameters of spaceborne synthetic aperture radars operating in the pulsed mode. Relationships are obtained and presented that make it possible to calculate dimensions of the antenna aperture, repetition period of the transmitter pulses and their duration, as well as duration of the pulse strobes opening the receiving device input, size of the antenna aperture, radiometric sensitivity and resolution, transmitter pulse power, bandwidth of the signal modulating the carrier frequency, aperture synthesis time and information flow rate. The technique is implemented on a personal computer in the C++ environment. The program menu with windows for input of initial data and output of simulation results is presented displayed in the form of 9 types of parametric dependences of the SAR characteristics on the observation point viewing angle. Technique introduction makes it possible to quickly, conveniently and with satisfactory accuracy perform systematic assessment of the SAR main characteristics choosing the most preferable options in the equipment basic parameter combinations. [ABSTRACT FROM AUTHOR]

The binocular telescope is characterized by the presence of a symmetric and parallel double optical system for each eye separately. It consists of a refractive optical system that contains a set of achromatic lenses and a Porro prism inside a plastic tube. The function of the prism is to reduce the length of the telescope as well as change the optical path of the rays to obtain an image suitable for human vision. The use of this type of telescope is suitable for ground observation due to the engineering nature of the design, as well as the focal lengths used for the lenses and the magnification factor. In addition to the use of lenses for refractive telescopes, it is suitable for ground observation rather than astronomical observation due to the presence of chromatic aberration and the small size of the pupil aperture. This research includes a study of the refracting binary telescope by simulation the design, and the study of its optical properties by using of Zemax program for optical designs. The program provides a set of analysis tools to assess the efficiency of the performance of the telescope when the pupil aperture changes. The results showed the effect of image quality when changing the diameter of the pupil aperture due to the change in the achromatic aberration value. [ABSTRACT FROM AUTHOR]

The article deals with a method of mathematical modeling of input signals of radar systems with synthesizing the aperture of an X-band antenna with the implementation of the method of direct solution of the correlation integral. The solution of the problem of onboard radar input signals simulation based on the polygonal model of objects and underlying surfaces that form the radar scene is presented. The possibility of solving the problem of calculating the scattering fields of triangular elements of a radar scene based on phenomenological models for underlying surfaces and on the basis of physical optics methods for anthropogenic objects is shown. In the used methods of physical optics, the induced electromagnetic field on the surface of an element of the object of the radiophysical scene is calculated through the Fresnel reflection coefficients for the horizontal and vertical polarization of the incident wave, and the reflected secondary field is determined through the Stratton-Chu integral. This approach makes it possible to take into account the surface materials of objects of a radiophysical scene with any types of dielectric and magnetic parameters, which allows to consider the proposed method as a universal tool for modeling input signals of radar systems scattered from objects of different electrophysical properties. Radar images of typical scenes from various underlying surfaces with objects located on them are presented on the basis of mathematical modeling. [ABSTRACT FROM AUTHOR]