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This paper uses the Haida iFLY-U3 fixed-wing UAV for image data acquisition. Based on UAV low-altitude photogrammetry technology, field control measurement method, such as Agisoft PhotoScan and Pix4D Mapper software, can process and produce DEM and DOM. Practical research on the processes and key technologies of digital products is under process. The field checkpoint measurement for the accuracy of DOM digital products made by low-altitude digital photogrammetry technology creates a basis for the practical application and development of digital products. The main contents of this paper are as follows: (a) The basic principles and processes of digital products for drone remote sensing image production, such as control point layout and measurement methods. (b) Based on the UAV photography technology, the digital product DOM and the field measurement control point accuracy evaluation are generated. (c). The polynomial curve digital model method is used to solve the elevation correction value, and the quadratic polynomial fitting model of the elevation point of the internal digital product is established, and the precision analysis is carried out.

The quality of the stereo camera calibration method governs the accuracy of the binocular vision and thus determines the precision of the 3D reconstruction. Spurred by that, in this paper, we propose an improved calibration method that increases the calibration accuracy by optimizing the captured corners. Our method is multi-staged, where first, we employ the Harris corner detector to identify the uncertainties of all image corners. Then, for each detected corner, we apply a linear optimization, and finally, we calibrate the intrinsic and extrinsic parameters of the binocular vision setup by employing a nonlinear optimization scheme. We confirm the validity of our technique by analyzing the factors influencing the camera calibration accuracy and confirm the experimental conditions. Ultimately, we evaluate the proposed method and demonstrate that the mean error of our binocular vision architecture is more appealing compared to current literature.

For the interpolating element-free Galerkin (IEFG) method set up by combining the shape function constructed with interpolating moving least-squares (IMLS) approximation and Galerkin integral weak form of partial differential equation, we show that the task of accuracy analysis of the IEFG method in solving transient heat conduction problems can be reduced to the estimation of errors in the procedure of IMLS approximation and the integral weak form of heat conduction equation. Following this practice, accuracy analysis of IEFG method is derived. To illustrate our results, numerical tests are discussed by two examples and give an optimal convergence rate with respect to two types of norm.

Ionospheric influence is one of the main factors that restrains high precision positioning of Continuously Operating Reference Stations (CORS). This paper analyses the Vertical Total Electron Content (VTEC) polynomial model, calculates the total electron content of ionospheric delays from eight CORS stations by subsection modeling, and uses a third order spline interpolation function to carry out the fitting analysis of VTEC curve. A certain relationship is concluded between the distribution of CORS stations and ionospheric delays, which can be more competent to reflect the variation of daily electron content and maintain the continuity and smoothness of the total electron content in space.