Method for determining spatial position of unmanned aerial vehicle for determining spatial coordinates of object points from processing images obtained from unmanned aerial vehicle

Abstract

FIELD: navigation.SUBSTANCE: invention relates to the field of navigation, photogrammetry, geodesy, cartography and can be used for constructing orthophoto plans, topographic plans, maps, three-dimensional models of terrain, buildings and structures, for solving engineering and geodetic problems, cadastral problems, and mine surveying. The claimed method is intended for determining the spatial coordinates of object points from the processing of images obtained from an unmanned aerial vehicle. A robotic tacheometer is installed on the terrain subject to aerial survey and provides direct visibility of the unmanned aerial vehicle (UAV) during the aerial survey of the terrain. A reflective prism is installed on the UAV, and the position of the front nodal point of the camera lens is measured relative to the centre of the reflective prism. The UAV is launched into airspace, and the operator of the tacheometer points it at the UAV. The tacheometer finds the reflective prism and focuses on it, after which it begins automatic tracking and position determination, while the time tp for determining the coordinates of the reflective prism is recorded. The UAV moves along a given route at a given altitude with a given speed and performs a survey of the terrain / object with a given longitudinal and transverse overlap. The aerial photography is completed and the UAV is landed. Control measurements are performed of the position of the front nodal point of the camera lens relative to the centre of the reflective prism, the average value of the reduction parameters is calculated, the spatial coordinates of the reflective prism are determined at the moments of photographing tm, and the coordinates of the projection centre of the camera are determined at the moments of photographing tm by taking into account the reduction parameters. The spatial coordinates of a set of object points are determined from the processing of aerial photographs using the method of constructing and adjusting analytical phototriangulation.EFFECT: determination of spatial coordinates of points of the object under study with an error of no more than 0.015 m by determining only the linear elements of the external orientation of the survey camera, without determining the angular elements of the external orientation of the survey camera of an unmanned aerial vehicle (UAV).5 dwg, 4 tbl

Description

[0001] The proposed invention relates to the field of navigation, photogrammetry, geodesy, cartography and can be used for constructing orthophoto plans, topographic plans, maps, three-dimensional models of terrain, buildings and structures, for solving engineering and geodetic problems, cadastral problems, mine surveying, etc. with a possible error in determining spatial coordinates of no more than 0.015 m (15 mm), and is implemented in practice using an unmanned aerial vehicle (hereinafter referred to as UAV), a robotic tacheometer and a computing program for processing aerial photographs.

[0002] The declared technical solution enables determination of spatial coordinates of terrain points and objects located on the terrain with an accuracy that meets the requirements of GOSTs, instructions, norms and rules used in geodesy, cartography, engineering and geodetic surveys, cadastre, mine surveying, and restoration of cultural heritage sites, for example, GOST R 56905-2016 "Conducting survey and engineering and geodetic works at cultural heritage sites. General requirements", Order of the Federal Service for State Registration, Cadastre and Cartography dated October 23, 2020 N P / 0393 "On approval of requirements for the accuracy and methods for determining the coordinates of characteristic points of the boundaries of a land plot, requirements for the accuracy and methods for determining the coordinates of characteristic points of the contour of a building, structure or unfinished construction project on a land plot, as well as requirements for determining the area of ​​​​a building, structure, premises, parking space."

[0003] The claimed technical solution can be used as an example of a reference measurement using a geodetic measuring instrument, namely a robotic tacheometer, of the spatial position of a UAV used in the field of determining the coordinates of terrain points, points of objects located on the ground.

[0004] The claimed technical solution is aimed at determining the linear elements of external orientation of photographs, necessary for determining the spatial coordinates of terrain points, points of objects located on the terrain, based on the measured coordinates of their images in photographs obtained using an unmanned aerial vehicle equipped with the appropriate equipment and software.

[0005] Further in the text, the applicant provides terms that are necessary to facilitate a clear understanding of the essence of the declared materials and to eliminate contradictions and / or controversial interpretations when performing an examination on the merits.

[0006] Robotic total station - a device that determines the spatial coordinates of a point by measuring the horizontal, vertical angle and distance to the measured point, with the function of automatic guidance and tracking of a reflector (prism) indicating the point being studied.

[0007] The device scans an area using a built-in camera and laser rangefinder. The device locates and focuses on a reflector (prism), then begins automatic tracking of the reflector (prism) position. The device is equipped with servo drives and a control system that allows for remote measurements via a controller, meaning the operator need not be physically present at the instrument. The device can be used by a single operator.

[0008] Robotic total station is used for high-precision measurements. The accuracy of linear measurements on a reflector is from 0.5 mm + 1 mm per km to 5 mm + 5 mm per km (depending on the model). The accuracy of angle measurements is from 0.5 arc seconds. The device is equipped with special software and internal memory [https: / / www.geokontinent.ru / company / articles / 1342 / ?ysclid=mg2i8xg3l5577852561];[https: / / ngcm.ru / blog / taheometr_ustroistvo / ?ysclid=mg2hws1bb0177626247] (accessed: 10 / 29 / 25).

[0009] Global Navigation Satellite System (GNSS)- a system designed to determine the location (geodetic coordinates, geographical coordinates) of land, water, air objects, as well as low-orbit spacecraft using navigation artificial Earth satellites that transmit a signal containing encrypted information about the satellite identifier, its location, exact on-board time, etc. The US GNSS - GPS (Global Positioning System) uses the general terrestrial (international) coordinate system WGS-84 (World Geodetic System). The Russian GNSS - GLONASS - uses the general terrestrial (international) coordinate system PZ-90.11 [https: / / chelyabinsk.eftgroup.ru / blog / raznoe / gnss-globalnyy-razbor / #first] (date of access: 10 / 29 / 25).

[0010] Satellite geodetic equipment(GNSS equipment) is a radio receiving device that determines the geographic coordinates, geodetic coordinates of the current location of the antenna of the receiving device based on data from radio signals emitted by navigation system satellites [https: / / forumtech.ru / novosti-v-sfere-telekommunikaczij / tpost / u53exe6os1-sputnikovoe-geodezicheskoe-oborudovanie?ysclid=mg925dmrne611759465] (date of access 10 / 29 / 25).

[0011] Local coordinate system - a coordinate system used in small administrative districts, construction sites, and land parcels. The abscissa axis (X-axis) is aligned with the meridian passing through the point on the terrain selected as the origin of the coordinate system, or is directed parallel to major highways, building axes, development lines, etc. The origin of the coordinate system can be designated, for example, based on the condition that all points of an object or area have positive coordinates [https: / / studfile.net / preview / 9529903 / page:4 / ].

[0012] The object under study (hereinafter referred to as the object) - by this term, in the context of this description, the applicant means any object located on the terrain, for example, a building, a structure, as well as a fragment of the terrain.

[0013] Image - by this term in the context of this description the applicant means photographic images obtained using a photographic camera (digital, analog).

[0014] Longitudinal overlap of images - overlap between images of one survey route, measured as a percentage [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: MIIGAiK Publishing House, 2022. p. 82]; [Nazarov A. S. Photogrammetry. Minsk: TerraSystems, 2010. p. 151].

[0015] Transverse overlap of images - overlap between images of adjacent survey routes, measured as a percentage [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: MIIGAiK Publishing House, 2022. p. 82]; [Krasnopevtsev V. V. Photogrammetry. Moscow: UPP "Reprografiya" MIIGAiK, 2008. pp. 23-24].

[0016] Image processing- by this term in the context of the present description the applicant means the process of performing an action on a material object, namely on a digital or analog image (photograph), with the help of material means, namely with the help of any measuring instrument either in manual mode, or in automatic mode, or in semi-automatic mode, that is, using a partially manual, partially automatic mode.

[0017] Spatial coordinates - by this term in the context of the present description the applicant means rectangular (Cartesian) coordinates [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. p. 11].

[0018] Linear elements of external orientation (position) of the shooting camera (photo) - coordinates (X S , Y S , Z S) the projection center of the UAV camera in relation to the origin of the selected spatial coordinate system [Chibunichev A.G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 11-16].

[0019] Corner elements of external orientation (orientation) of the shooting camera (photo) - three angles (φ, ω, κ), which determine the position (tilt) of the UAV shooting camera relative to the axes of the selected spatial coordinate system [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 11-16].

[0020] Elements of interior orientation shooting camera (photograph) - focal length of the shooting camera f, coordinates x0, y0 of the principal point of the photograph and lens distortion parameters Chibunichev A. G. Photogrammetry: textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 9-11].

[0021] Object points (terrain)- By this term, in the context of this description, the applicant means the conventional points that make up the object (terrain) being studied. The number of points on the object selected for measurement determines the level of detail in constructing the three-dimensional model of the object within a certain spatial coordinate system.

[0022] Control points (reference points) - by this term in the context of the present description the applicant means the points indicated (located) on the object under study spatial coordinates (X к ,Y к ,Z к) which are determined with a given accuracy before or after aerial photography [Nazarov A.S. Photogrammetry. - Minsk: TerraSystems, 2010. p. 246] [https: / / docs.yandex.ru / docs / view?tm=1761977146&tld=ru&lang=ru&name=2455.pdf&text=%5Bhttps%3A%2F%2Fbooks.ifmo.ru%2Ffile%2Fpdf%2F2455.pdf%20%D1%81.%20119%20-120%5D.&url=https%3A%2F%2Fbooks.ifmo.ru%2Ffile%2Fpdf%2F2455.pdf&lr=43&mime=pdf&l10n=ru&sign=03502ae8a2d3d811de648a696b225fff&keyno=0&nosw=1&serpParams =tm%3D1761977146%26tld%3Dru%26lang%3Dru%26name%3D2455.pdf%26text%3D%255Bhttps %253A%2F%2Fbooks.ifmo.ru%2Ffile%2Fpdf%2F2455.pdf%2B%25D1%2581.%2B119%2B-120% 255D.%26url%3Dhttps%253A%2F%2Fbooks.ifmo.ru%2Ffile%2Fpdf%2F2455.pdf%26lr%3D4 3%26mime%3Dpdf%26l10n%3Dru%26sign%3D03502ae8a2d3d811de648a696b225 fff%26keyno%3D0%26nosw%3D1] (date of access: 10 / 31 / 20).

[0023] Gyrostabilized platform- a device for spatial stabilization of any objects or devices, as well as for determining the rotation angles of the base on which it is installed. It is used to eliminate the influence of external factors that cause devices located on the platform to move out of their intended position [http: / / npo-karat.ru / page / 16-56 / ] (date of access 01.11.25).

[0024] Construction and adjustment of phototriangulation - is carried out with the aim of determining the elements of external orientation of photographs and spatial coordinates of object points in the object's coordinate system by constructing and externally orienting a photogrammetric model of the object based on photographs belonging to one or several overlapping routes [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing House MIIGAiK, 2022. p. 70].

[0025] Root Mean Square Error (RMSE)- in probability theory and statistics, the most common indicator of the dispersion of the values ​​of a random variable relative to its mathematical expectation [https: / / ru-wiki. Root mean square error]. To simplify the text's comprehension, the applicant, in the context of this description, also uses the terms "error" and "accuracy" to denote the "root mean square error."

[0026] It is known from the prior art that a UAV is a carrier of a payload, for example, a digital camera, with the help of which photographing (filming) of the objects under study (fragments of terrain, buildings, engineering structures, etc.) is performed. Aerial photography from a UAV is used for mapping, solving engineering and geodetic problems, and cadastral survey [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: MIIGAiK Publishing House, 2022. pp. 102-107]; [Nazarov A. S. Photogrammetry. - Minsk: TerraSystems, 2010. pp. 52-53]; [Limonov A. N., Gavrilova L. A. Photogrammetry and Remote Sensing. - Moscow: Academichesky Proekt. 2016. pp. 75-76]; [Babashkin N.M., Kadnichansky S.A., Nekhin S.S. Comparison of the efficiency of aerial phototopographic survey using unmanned and manned aircraft systems. Geoprofi, No. 1, 2017. - pp. 14-19].

[0027] It is well known that calculating the spatial coordinates of object points from the coordinates of their images requires knowledge of the exterior orientation elements (hereinafter referred to as EOO), namely the linear and angular elements of exterior orientation that characterize the spatial and angular position of the shooting camera relative to the selected spatial coordinate system. In the absence of values ​​for the exterior orientation elements, to determine the spatial coordinates of object points from the coordinates of their images, reference points located on the object are used [Chibunichev A. G. Photogrammetry: textbook for universities. Moscow: MIIGAiK Publishing House, 2022. pp. 11-16]; [Nazarov A. S. Photogrammetry. Minsk: TerraSystems, 2010. pp. 52-53]; [Limonov A. N., Gavrilova L. A. Photogrammetry and Remote Sensing. Moscow: Academic project. 2016. p.75-76].

[0028] It is also known from the prior art that the most effective for use in the stated purposes, namely, for determining the coordinates of object points with an error (RMS) of no more than 0.015 m (15 mm) are multicopter UAVs [Babashkin N.M., Kadnichansky S.A., Nekhin S.S. Comparison of the effectiveness of aerial phototopographic survey using unmanned and manned aircraft systems. Geoprofi, No. 1, 2017. - pp. 14-19]; [Patent for invention RU No. 2681836. Method for determining the spatial coordinates and angular position of a remote object]; [Patent for invention RU No. 2744427. Complex for determining the spatial coordinates of a remote object located on the ground].

[0029] The applicant has completed an analysis of the state of the art in the specified field using Russian and foreign patent databases, articles, and Internet resources on the topic of using UAVs to determine the spatial coordinates of object points in real time and in post-processing mode (hereinafter referred to as post-processing).

[0030] Analysis of the state of the art in this field allows us to conclude that the technical problem of determining the spatial coordinates of object points is relevant and has not yet been adequately resolved. That is, as of the filing date, there is a pressing problem of determining the spatial coordinates of object points based on the measured coordinates of their images in photographs without the use of reference points, including with an error (standard deviation) of no more than 0.015 m (15 mm).

[0031] It is known from the prior art that the position of a UAV in space - as a remote object, can be determined using rangefinder-angle measuring instruments [Patent for invention RU No. 2567865. Method for positioning a remote object using rangefinder-angle measuring instruments]. The essence of the known technical solution is a method for positioning a remote object using rangefinder-angle measuring instruments, which consists in the fact that there are at least three rangefinding units, one of which is the gunner's rangefinding unit, spatially located at some distance from each other and from the object, but within the line of sight of the object, and the coordinates of the rangefinding units are determined in one of the selected coordinate systems, while the rangefinding units point their rangefinding-angle measuring instruments at the object and determine the distance to the remote object, after which the coordinates of the object are determined by the intersection of spheres with centers in three or more rangefinding units,characterized by the fact that first the gunner's rangefinder unit aims its rangefinder-angle measuring instrument at the object and determines the distance and angular coordinates of the object, then, based on these measurements, a first approximation of the object's coordinates is calculated, which are then transmitted to the remaining rangefinder units, which, based on these coordinates, aim their rangefinder-angle measuring instruments and measure the distance to the object, then, based on the measured distances, a second approximation of the object's coordinates is calculated, using for this purpose the distance from the gunner's rangefinder unit and a plurality of combinations of distances from the rangefinder units to the object, taken in pairs, then the calculated coordinates of the object are transmitted to the remaining rangefinder units, which, based on these coordinates, re-aim their rangefinder-angle measuring instruments and determine the distance to the object, then, based on the measured distances, a third approximation of the object's coordinates is calculated, and so on,until the difference in determining the coordinates of an object in two adjacent approximations of the coordinates of an object in the order of execution becomes less than the threshold value.

[0032] The disadvantage of the known technical solution compared to the declared technical solution is:

[0033] • low accuracy (more than 0.5 m) of determining the position, i.e. spatial coordinates X, Y, Z of a remote object (UAV), since the measurement of vertical and horizontal angles and the measurement of range are performed to an arbitrary point on the surface of a remote object (UAV), which does not allow for further determination of the spatial coordinates of the points of the object under study from the processing of aerial photographs with a stated error (RMS) of no more than 0.015 m (15 mm);

[0034] • the need to use at least three angle-measuring devices and ensure direct visibility between them;

[0035] • high technological complexity of implementing the process of simultaneous targeting (observation) of a remote object (UAV);

[0036] • high labor intensity of the implementation of the process of targeting (observing) a remote object (UAV) and determining its spatial coordinates X, Y, Z and the need to use a trained gunner in the known technical solution.

[0037] An invention is known in which a robotic total station is used to determine the coordinates of a UAV [Patent for Invention No. RU 0002809177. Method of using a robotic total station and an unmanned aerial vehicle to determine the coordinates of a ground object]. The essence of the known technical solution is that the coordinates of a ground object are determined using a robotic total station and an unmanned aerial vehicle (UAV), on the gyrostabilized platform of which a sighting target (ST), a transceiver, a video camera, and a laser rangefinder are mounted such that the optical axis of the video camera and the laser rangefinder beam are directed vertically downward. The UAV hovers above the ground object, the elevation above which is determined by the laser rangefinder.The ground target is tracked using a robotic total station equipped with a video camera and a tracking and detection subsystem. The total station's image is digitally processed, using the total station's measured range, zenith, and azimuth angles, as well as the elevation above the ground object measured with a laser rangefinder. The operator hovers the UAV over the ground object using a video camera. The laser rangefinder attached to the UAV then transmits the measurement results via a radio telemetry system, and the UAV's elevation above the ground object is determined. The current location of the robotic total station is used as the origin.The coordinates of a ground object are calculated based on the results of measuring the horizontal, vertical angle and distance to the UAV, as well as the distance measured from the UAV to the ground object over which the UAV is hovering.

[0038] The main disadvantages of the known solution are:

[0039] • the need to place additional equipment on the UAV, namely a laser rangefinder, to measure the distance from the UAV to a point on a ground object, the spatial coordinates of which must be determined;

[0040] • the need for the UAV to hover over a ground object, the coordinates of which are determined, in order to measure the distance from the UAV to the object using a laser rangefinder and, as a consequence, low productivity;

[0041] • the absence of a camera that allows photographing the area and obtaining overlapping images necessary for determining the spatial coordinates of a large number of object points.

[0042] A known solution uses a robotic total station and a reflective prism mounted on the UAV to determine the spatial coordinates of the UAV. The solution involves the use of an original reflective prism that is attached to the lens of the shooting camera (Topcon, Sokkia, Japan) [https: / / www.topconpositioning.asia / jp / ja / products / brand / sokkia / tstrackinguas / ];[https: / / www.youtube.com / watch?v=rPtx0DmHCmc];[https: / / www.thegpstime.com / rotary-wing-drone-compatible-with-the-aerial-photo-surveying-system / ] (accessed: 10 / 29 / 25). However, the parameters characterizing the error in determining the spatial coordinates and other parameters characterizing the technical solution are not provided.

[0043] The main disadvantages of the known solution are:

[0044] • the reflective prism mount does not allow the robotic total station to reliably track the reflective prism without interrupting this process when the UAV turns, when approaching the next flight route, and when performing other UAV maneuvers due to the conditions of the aerial survey of the object, the position of the UAV relative to the robotic total station;

[0045] • impossibility of quickly replacing the reflective prism with another prism;

[0046] • the need to install a reflective prism when replacing the camera lens and measuring the new reduction (misalignment of the front nodal point of the camera lens with the center of the reflective prism);

[0047] • Replacing the camera on a UAV requires installing a reflective prism;

[0048] • the inability to install commercially available reflective prisms, such as those used for geodetic measurements.

[0049] The invention of the applicant under the Russian Federation patent No. 2681836 "Method for determining the spatial coordinates and angular position of a remote object" is known. In the known technical solution, the remote object is a UAV. The essence of the known technical solution is a method for determining the spatial coordinates and angular position of a remote object using rangefinding stations, which consists in using at least three rangefinding stations spatially located at some distance from each other and from the remote object, within the line of sight of the remote object, wherein the coordinates of the rangefinding stations are determined in a spatial coordinate system, wherein the rangefinding stations point their rangefinders at the remote object and determine the distance to the remote object, after which the coordinates of the remote object are determined by the intersection of spheres with centers in three or more rangefinding stations, the approximate coordinates of the position of the remote object are calculated, characterized in that,that the orientation of the rangefinder stations is performed as follows: rangefinder station 1 is oriented toward rangefinder station 2, rangefinder station 2 is oriented toward rangefinder station 3, rangefinder station 3 is oriented toward rangefinder station 1, with the possibility of increasing the number of rangefinder stations to 4 or more, measurements of distances between the rangefinder stations are performed, a spatial coordinate system is calculated and set, wherein the coordinates of each subsequent, 4th or more, rangefinder station are determined in the spatial coordinate system set by rangefinder stations 1, 2, 3 by measuring the distances from each subsequent, 4th or more, rangefinder station to rangefinder stations 1, 2, 3, the coordinates of the rangefinder stations and the remote object, which is an unmanned aerial vehicle, are determined in the global coordinate system using GLONASS / GPS equipment,determine the parameters of the transition from the global coordinate system to the spatial coordinate system, determine the approximate coordinates of the unmanned aerial vehicle in the spatial coordinate system specified by the rangefinder stations with an accuracy of 2 m using the parameters of the transition from the global coordinate system to the spatial coordinate system, calculate the horizontal and vertical guidance angles for each of the rangefinder stations, automatically point the rangefinder stations at the unmanned aerial vehicle, measure the distance from the rangefinder station to the reflectors attached to the unmanned aerial vehicle, then, based on the measured distances to each individual reflector, determine the coordinates of each reflector using the method of intersection of spheres from three or more rangefinder stations,determine the exact coordinates of the unmanned aerial vehicle in a spatial coordinate system as the average value between the coordinates of all reflectors, calculate the angular position of the unmanned aerial vehicle, i.e. determine the angular position of the unmanned aerial vehicle based on the calculated coordinates of the reflectors, then calculate the spatial coordinates of points on the ground based on the measured coordinates of their images obtained by a camera installed on the unmanned aerial vehicle, using the coordinates of the unmanned aerial vehicle and the angular position of the unmanned aerial vehicle in the spatial coordinate system.

[0050] The known technical solution includes a ground-based measuring system and a system mounted on a UAV, and consists of at least six separate assembly elements, including three range-finding stations, namely:

[0051] • rangefinder stations (RS), mounted on tripods, in quantities of at least three pieces;

[0052] • control unit for rangefinder stations;

[0053] • A UAV equipped with reflectors (at least 3 reflectors), the reflector must ensure the return reflection of the laser beam, i.e. the reflection of the beam in the opposite direction (towards the DS) at any angle of incidence of the laser beam emanating from the DS;

[0054] • UAV control unit.

[0055] The disadvantages of the known technical solution compared to the declared technical solution are:

[0056] • the need to use at least three rangefinding stations, each of which is automatically aimed at the UAV and determines the distance to the reflectors installed on the UAV, while guidance to the UAV is implemented through the use of GNSS equipment located on the UAV and at the rangefinding stations;

[0057] • the need to place on the UAV at least three reflectors, which are installed at a certain distance relative to each other, while the distance between the reflectors must be known with high accuracy, and in order to achieve unambiguity, namely - to which reflector the distance from a specific DS was measured, the measurement of the distance from an individual DS to each reflector installed on the UAV is carried out according to the principle: “one reflector is accessible, the rest are inaccessible”, which will reduce the accuracy of determining the spatial and angular position of the UAV and, accordingly, reduce the accuracy of determining the spatial coordinates of the points of the object under study;

[0058] • the need to determine the spatial coordinates of the UAV, as well as the angular position, i.e. the angular orientation of the UAV;

[0059] • high technological complexity of implementing the process of simultaneous guidance (observation) of rangefinder stations on UAVs in order to determine the spatial and angular position of the UAV by measuring the distances to reflective prisms, based on the principle: “one reflector must be accessible, the rest are inaccessible.”

[0060] The identified analogs coincide with the declared technical solution in terms of individual matching features, therefore the prototype was not identified and the invention formula was drawn up without a limiting part.

[0061] The technical problem solved by the claimed invention and its technical result is the elimination of the disadvantages of analogues:

[0062] - ensuring the ability to determine the spatial coordinates of the points of the object under study with an error of no more than 0.015 m, i.e. a standard deviation of 15 mm, by determining only the linear elements of the external orientation of the camera, without determining the angular elements of the external orientation of the UAV camera;

[0063] - ensuring the determination of the spatial position of the UAV (i.e. linear elements of external orientation) with an error (RMS) of no more than 0.01 m, i.e. 10 mm, using one angle-measuring and range-finding device, namely a robotic total station, while only one reflecting prism (triple prism) is installed on the UAV;

[0064] - providing the possibility of installing a reflective prism (triple prism) on a UAV, which is produced in series, for example, for geodetic measurements, while the installation of the prism can be performed using a universal (multifunctional) device;

[0065] - eliminating the need to replace the reflective prism when replacing the lens of the shooting camera, as well as when replacing the shooting camera itself;

[0066] - providing the possibility (if necessary) of quickly replacing one reflective prism with another;

[0067] - eliminating the need to install a rangefinder on board a UAV and hover the UAV over an object to determine the spatial coordinates of the object’s points;

[0068] - ensuring a reduction in the labor intensity of the process of targeting a UAV and determining its spatial coordinates;

[0069] - providing a higher technological implementation of the process of determining the spatial coordinates of a set of points of an object from the processing of aerial photographs of the object without using reference points on the object.

[0070] The essence of the claimed invention is a method for determining the spatial position of an unmanned aerial vehicle for determining the spatial coordinates of object points from processing images obtained from an unmanned aerial vehicle, characterized in that a robotic total station is installed on the terrain to be aerially surveyed, while ensuring direct visibility of the unmanned aerial vehicle UAV during the aerial survey of the terrain; synchronizing the clock of the robotic total station and the clock of the UAV; a reflective prism is installed on the UAV in such a way as to ensure the possibility of tracking it by the robotic total station without interrupting this process when the UAV turns, when approaching the next flight route and other maneuvers of the UAV caused by the conditions of the aerial survey of the object;the position of the front nodal point of the camera lens is measured relative to the center of the reflective prism - the reduction parameters ΔX1, ΔY1, ΔZ1 are determined with an error of no more than 1 millimeter, while the reduction parameters are measured using a measuring instrument before and after the aerial survey; the UAV is launched into airspace, while the operator of the robotic total station points it at the UAV; the robotic total station finds the reflective prism and focuses on it, after which it begins automatic tracking and determining the position - the spatial coordinates of the reflective prism of the UAV X; P , Y P , Z P , which are determined in the coordinate system of the robotic total station using the software of the robotic total station, while recording the time t рdetermining the coordinates of the reflective prism; the UAV moves along a given route at a given altitude with a given speed and takes pictures of the terrain / object with a given longitudinal and transverse overlap, while the onboard UAV system records the time of photography t m , while the movement of the UAV along the flight routes is performed in automatic or manual mode, and the transverse overlap - the overlap between the images of adjacent routes is not less than 40% and not more than 80%; complete the aerial survey and land the UAV; perform control measurements of the position of the front nodal point of the camera lens relative to the center of the reflective prism - determine the reduction parameters ΔX2, ΔY2, ΔZ2 with an accuracy of no more than 1 mm, while the measurement of the reduction parameters is performed using a measuring instrument; calculate the average value of the reduction parameters ΔX = (ΔX1 + ΔX2) / 2; ΔY = (ΔY1 + ΔY2) / 2; ΔZ = (ΔZ1 + ΔZ2) / 2; determine the spatial coordinates XPTm , Y PTm , Z PTm reflective prism at the moments of photographing t m , while using time t р determination of the coordinates of the reflective prism, photographing time t m and apply interpolation methods; determine the X coordinates Sm , Y Sm , Z Sm projection center of the shooting camera at the time of shooting t m by taking into account the reduction parameters ΔX, ΔY, ΔZ, which characterize the displacement of the front nodal point of the camera lens relative to the center of the reflective prism: X Sm = X PTm - ΔX, Y Sm = Y PTm - ΔY, Z m = Z PTm - ΔZ; determine the spatial coordinates X i , Y i , Z i sets of object points from the processing of aerial photographs, using the method of constructing and adjusting analytical phototriangulation based on the use of projection centers with known X coordinatesSm , Y Sm , Z Sm as reference points; in this case, the listed actions are performed by two operators: the UAV operator and the robotic tacheometer operator, while the determination of the spatial coordinates of a set of object points from the processing of aerial photographs is implemented using known software packages.

[0071] The claimed technical solution is illustrated in Fig.1 - Fig.9.

[0072] Fig. 1 shows a basic diagram of the claimed method, a general view of the position of the unmanned aerial vehicle (UAV) during surveying, the position of the robotic total station, where: 1 - UAV; 2 - robotic total station; X'Y'Z' - coordinate system of the robotic total station; α S , ν S- horizontal and vertical angles, respectively; L1, L2, L3 - distances measured by a robotic total station to a reflecting prism mounted on a UAV; OXYZ - object coordinate system (topocentric coordinate system, international coordinate system WGS-84 (USA), PZ-90.11 (Russia), other coordinate systems).

[0073] Fig. 2 shows a photograph of a robotic total station mounted on a tripod, where: 1 - UAV; 2 - robotic total station on a tripod.

[0074] Fig. 3 shows a photograph of a UAV with a fixed reflective prism, where: 3 - reflective prism (triple prism); 4 - filming camera; 5 - levers for attaching to an external device - UAV; 6 - lever for attaching the reflective prism.

[0075] Fig. 4 shows a schematic diagram explaining the reduction parameters that characterize the position of the front nodal point of the camera lens relative to the center of the reflective prism, where: 3 is the reflective prism (triple prism); 4 is the camera, on the lens of which the position of the front nodal point of the lens is indicated; XYZ is the coordinate system of the camera, the Z axis of which coincides with the optical axis of the camera and is directed upward, the X axis is perpendicular to the Z axis and is directed in the direction of flight of the UAV, the Y axis complements the coordinate system to a right-hand coordinate system, ΔX, ΔY, ΔZ are the reduction parameters.

[0076] Fig. 5 shows a photograph of a universal (multifunctional) device for attaching a reflective prism, where: 5 - levers for attaching to an external device - a UAV; 6 - lever for attaching a reflective prism; 7 - screw for attaching a reflective prism; 8 - handle of the screw that tightens the levers for attaching to an external device; 9 - anti-slip rubber; 10 - a locking plate of the lever for attaching a reflective prism, which fixes the position of the screw for attaching the reflective prism 7 relative to the lever for attaching the reflective prism 6, and also fixes the position of the lever for attaching the reflective prism 6 relative to the levers for attaching to the external device 5; 11 - handle of the screw that presses the locking plate 10 to the lever for attaching the reflective prism 6.

[0077] Fig. 6 shows Table 1, which lists the values ​​of the coordinates of the projection centers of the images (taking into account the reduction parameters ΔX, ΔY, ΔZ of the front nodal point of the camera lens relative to the center of the reflective prism); the error (RMS) in determining the coordinates of the projection centers (Example 1).

[0078] Fig. 7 shows Table 2, which shows the accuracy assessment (RMS) for determining the spatial coordinates X i ,Y i ,Z i object points using control points, containing the coordinates of the control points obtained using a robotic total station; the coordinates of the control points obtained from processing images; the differences between the corresponding coordinates, the errors (standard deviation) (Example 1).

[0079] Fig. 8 shows Table 3, which lists the values ​​of the coordinates of the centers of the projection of the images (taking into account the reduction parameters ΔX, ΔY, ΔZ of the front nodal point of the camera lens relative to the center of the reflective prism), the error (RMS) in determining the coordinates of the centers of the projection of the images (Example 2).

[0080] Fig. 9 shows Table 4, which shows the accuracy estimate (RMS) for determining the spatial coordinates X i , Y i , Z i points of the object using control points, containing the coordinates of the control points obtained using a robotic total station, obtained from processing images, and the errors (standard deviation) corresponding to them (Example 2).

[0081] The following is a description of the claimed method.

[0082] The following equipment is used in the claimed method.

[0083] 1. Robotic total station, mass-produced for geodetic measurements, for example, the Leica TS60 I 0.5" R1000 total station [https: / / www.geooptic.ru / product / leica-ts60-i-05?utm_source=yandex&utm_medium=cpc&utm_content=src_yandex.ru%7Cdevt_desktop%7Cregid_43%7Cregn_%D0%9A%D0%B0%D0%B7%D0%B0%D0%BD%D1%8C%7Cpost_dynamic_places%7Cpos_1%7Ccgci d_0%7Cct_type1%7Ccid_116943986%7Cgid_5524970609%7Caid_16734862325%7Cpid_53990948024%7Csrct_search%7Cmt_%7Cm k_&utm_term=---autotargeting&utm_campaign=geooptic_ya_tk_main_reg&etext&yclid=4043481048660312063&ybaip=1], total station TOPCON GT-1501 [https: / / www.gsi.ru / catalog / taheo / gt1501?ysclid=miylsm1cxl770707177].

[0084] The software is an integral component of the robotic total station. Robotic total stations are a measuring instrument and are included in the State Register of Measuring Instruments.

[0085] 2. Unmanned aerial vehicle (UAV), for example, the Phantom DJI Matrix 400 + Zenmuse P1 multicopter [https: / / pro-aero.ru / kvadrokopter-matrice-400-zenmuse-p1].

[0086] 3. Reflective prism (triple prism), mass-produced for geodetic measurements, for example, Orient CRZ4 360 [https: / / www.geooptic.ru / product / orient-crz4-360-prism-set?ysclid=miywlg0218147868454].

[0087] 4. A commercially available reflective prism mount, such as the Ulanzi R094 universal (multifunctional) clamp [https: / / www.ulanzi.com / products / ulanzi-r094-multi-functional-super-clamp-2638?srsltid=AfmBOoqQMLYjgvFJAU70M65_IseJqnqkViBpB4Ml1DGubgnmIGwTm4b2].

[0088] The claimed technical solution regarding the method for determining the spatial position of a UAV, i.e. the linear elements of the external orientation of the shooting camera, necessary for the further determination of the spatial coordinates of a set of points of an object based on the measured coordinates of their images in photographs obtained using an unmanned aerial vehicle, is characterized the following sequence of actions .

[0089] Robotic total station 2 is installed on the terrain to be surveyed. This ensures direct line of sight to UAV 1 during the aerial survey (Fig. 1, Fig. 2).

[0090] • Synchronizes the clock of the robotic total station 2 and the clock of the UAV 1.

[0091] • A reflective prism 3 (Fig. 3, Fig. 4) is installed on the UAV 1 in such a way as to enable its tracking by the robotic tacheometer 2 without interrupting this process when the UAV 1 turns, when approaching the next flight route and during other maneuvers of the UAV 1, determined by the conditions of aerial photography of the object.

[0092] • Measure the position of the front nodal point of the camera lens 4 relative to the center of the reflective prism 3, i.e. determine the reduction parameters ΔX1, ΔY1, ΔZ1 with an error of no more than 1 millimeter. Measurement of the reduction parameters is performed using a measuring instrument, for example, a caliper or electronic caliper.

[0093] • The UAV 1 is launched into the airspace, and the operator of the robotic total station 2 points it at the UAV 1 (Fig. 1). The robotic total station 2 finds the reflective prism 3 and focuses on it, after which it begins automatic tracking and determining the position (i.e., spatial coordinates) of the reflective prism 3. Spatial coordinates X P , Y P , Z P reflective prism 3 is determined in the coordinate system of the robotic total station 2 using the software of the robotic total station 2, while the time t is recorded р determining the coordinates of the reflective prism 3.

[0094] UAV 1 moves along specified routes at a specified altitude with a specified speed and takes pictures of the terrain / object with a specified longitudinal and transverse overlap, while the time of photographing t is recorded (by the on-board system of UAV 1) mThe movement of UAV 1 along flight routes is carried out in automatic mode or manual mode, i.e. controlled by the operator of UAV 1.

[0095] In this case, the transverse overlap (the overlap between images of adjacent routes) is no less than 40% and no more than 80%. The specified transverse overlap value is necessary and sufficient for determining the spatial coordinates of object points with a given accuracy from aerial imagery processing without creating control points on the object.

[0096] • Complete aerial photography and land UAV 1.

[0097] • After completion of the aerial survey, control measurements are performed of the position of the front nodal point of the camera lens 4, relative to the center of the reflective prism 3, i.e., the reduction parameters ΔX2, ΔY2, ΔZ2 are determined with an error of no more than 1 mm. The reduction parameters are measured using a measuring instrument, for example, a caliper or an electronic caliper. The average value of the reduction parameters is calculated

[0098] ΔX = (ΔX1+ΔX2) / 2; ΔY = (ΔY1+ΔY2) / 2; ΔZ = (ΔZ1+ΔZ2) / 2. 1)

[0099] • Determines the spatial coordinates X PTm , Y PTm , Z PTm reflective prism 3 at the moments of photographing t m To calculate the X coordinates PTm , Y PTm , Z PTm use time t р determining the coordinates of the reflective prism 3, photographing time t m and use known interpolation methods, including those implemented in well-known software designed for processing aerial photographs, for example, the digital photogrammetric system PHOTOMOD (hereinafter referred to as DPS PHOTOMOD) [https: / / racurs.ru / program-products / tsfs-photomod / ] (date of access: 10 / 29 / 25), Agisoft Metashape [https: / / www.agisoft.com / ru / features / professional-edition / ] (date of access: 12 / 29 / 25).

[0100] • Perform coordinate determination (X Sm , Y Sm , Z Sm) the projection center of the shooting camera 4 at the shooting moments t m by taking into account the reduction parameters ΔX, ΔY, ΔZ, which characterize the displacement of the front nodal point of the camera lens 4 relative to the center of the reflective prism 3

[0101] X Sm = X PTm - ΔX, Y Sm = Y PTm - ΔY, Z m = Z PTm - ΔZ. 2)

[0102] • Perform the determination of spatial coordinates (X i ,Y i ,Z i ) a set of object points from aerial photograph processing. This uses a well-known method for constructing and adjusting analytical phototriangulation, based on the use of projection centers with known coordinates (X Sm , Y Sm , Z Sm ) as reference points [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 80-86].

[0103] The listed actions are performed by two operators: UAV operator 1 and robotic total station operator 2. At the same time, the claimed technical solution is characterized by the fact that the determination of the spatial coordinates of a set of object points from the processing of aerial photographs is implemented through the use of well-known software packages, for example, PHOTOMOD Digital Photosystem [https: / / racurs.ru / program-products / tsfs-photomod / ], Agisoft Metashape [https: / / www.agisoft.com / ru / features / professional-edition / ].

[0104] If necessary, spatial coordinates (X i ,Y i ,Z i) the sets of points of the object can be defined in a different coordinate system, for example, in the general terrestrial (international) coordinate system WGS-84 (USA), PZ-90.11 (Russia), in the topocentric coordinate system, as well as in other coordinate systems. For this purpose, the required and sufficient number of control points are created on the object, the spatial coordinates of which are determined (before or after aerial photography) in the selected coordinate system and are used to control the accuracy of the construction and adjustment of phototriangulation in the selected coordinate system [Shekhovtsov G. A. Unified algorithm for adjustment, accuracy assessment and optimization of geodetic intersections. Nizhny Novgorod: NNGASU, 2017. pp. 34-46, pp. 77-85]. In this case, the coordinates of the control points must be determined with an error, which is determined by the formulas

[0105] , , 3)

[0106] where:

[0107] - errors (standard deviation) with which the spatial coordinates of reference points are determined, - total error in determining the coordinates of the reference point;

[0108] - errors (RMS) in determining the spatial coordinates of object points, obtained from processing aerial photographs in the coordinate system of robotic theodolite 2.

[0109] Examples of the implementation of the declared technical solution

[0110] The claimed technical solution regarding the method for determining the spatial position of a UAV, i.e. the linear elements of the external orientation of the camera, necessary for the further determination of the spatial coordinates of a set of points of an object based on the measured coordinates of their images in photographs obtained using an unmanned aerial vehicle, is confirmed by the following practical examples.

[0111] Example 1.Determination of the spatial position of an unmanned aerial vehicle for determining the spatial coordinates of object points from the processing of images obtained from an unmanned aerial vehicle, manual control of the UAV

[0112] • A robotic total station (Trimble S8) was installed on the site to be surveyed. Direct line of sight of the UAV was ensured during aerial survey of the object. The photographed object is a building, on the surface of which reference and control points have been created. Total station specifications: angle measurement accuracy of 0.5" arc seconds, distance measurement accuracy of 4 mm + 2 mm / km [file: / / / Users / Vladimir / Downloads / trimble-s8-lr.pdf].

[0113] • Synchronized the clock of the robotic total station and the UAV clock.

[0114] A reflective prism (triple prism) 360° Leica GRZ101 (Fig. 3, Fig. 5) was installed on a multicopter UAV (DJI Matrice 300) in such a way as to enable its tracking by a robotic total station without interrupting this process when the UAV turns, when the UAV enters the next flight route and other maneuvers of the UAV determined by the conditions of aerial photography of the object.

[0115] The reflective prism was attached to the UAV using a universal (multifunctional) device (Fig. 5). The levers for attaching to the external device 5, equipped with anti-slip rubber 9, were attached to the UAV using the handle of the tightening screw 8. The reflective prism was attached to lever 6 of the universal (multifunctional) device using screw 7. Lever 6 and the reflective prism (fastened with screw 7) were set in a position that ensures tracking of the reflective prism by the robotic total station and determination of the spatial coordinates of the reflective prism by the robotic total station during the movement of the UAV. The position of lever 6 and the reflective prism was fixed using locking plate 10 and the handle of screw 11 of the locking plate.

[0116] We measured the position of the front nodal point of the camera lens relative to the center of the reflective prism, i.e. determined the reduction parameters ΔX1, ΔY1, ΔZ1 with an accuracy of no more than 1 millimeter:

[0117] ΔX1= 0.0 mm ± 1.0 mm = +0.0 m ± 0.0010 m;

[0118] ΔY1= +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0119] ΔZ1= +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0120] The measurement of reduction parameters is performed using a measuring instrument, namely, a caliper.

[0121] The UAV was launched into airspace, and the operator of the robotic total station pointed it at the UAV. The robotic total station found the reflective prism and focused on it, after which it began automatically tracking and determining the position (spatial coordinates) of the reflective prism. The spatial coordinates (X P , Y P , Z P ) the reflective prism of the UAV was determined in the coordinate system of the robotic total station using the software of the robotic total station, while the time t was recorded р determining the coordinates of the reflective prism.

[0122] The UAV moves along a given route at a given altitude with a given speed and takes pictures of an object with a given longitudinal and transverse overlap, while the onboard UAV system records the photographing time t m .

[0123] The UAV's flight paths were controlled manually, i.e., by the operator. There were two routes, 11 images per route, and 22 total images. The longitudinal overlap between images was no more than 75%, and the transverse overlap (the overlap between images from adjacent routes) was 40%.

[0124] • Completed aerial photography and landed the UAV.

[0125] • After completion of the aerial survey, control measurements were taken of the position of the front nodal point of the camera lens relative to the center of the reflective prism, i.e. the reduction parameters ΔX2, ΔY2, ΔZ2 were determined with an accuracy of no more than 1 mm:

[0126] ΔX2= 0.0 mm ± 1.0 mm = +0.0 m ± 0.0010 m;

[0127] ΔY2= +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0128] ΔZ2= +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0129] The reduction parameters were measured using a caliper. The average value of the reduction parameters was calculated (using formula 1):

[0130] ΔX = 0.0 mm ± 1.0 mm = +0.0 m ± 0.0010 m;

[0131] ΔY = +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0132] ΔZ = +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0133] • Determined spatial coordinates X PTm , Y PTm , Z PTm reflective prism at the moments of photographing t m To calculate the X coordinates PTm , Y PTm , Z PTm time t was used р determining the coordinates of the reflective prism, using interpolation implemented in the well-known software TsFS PHOTOMOD, designed for photogrammetric processing of aerial photographs.

[0134] • Determined the coordinates of the projection centers of the X-ray camera Sm , Y Sm , Z Sm at the time of shooting t m by taking into account, using formula 2, the reduction parameters (ΔX, ΔY, ΔZ), which characterize the displacement of the front nodal point of the camera lens relative to the center of the reflective prism (Table 1, Fig. 6).

[0135] • Determined the spatial coordinates X i ,Y i ,Z i set of object points from the processing of aerial photographs using the photogrammetric software package TsFS PHOTOMOD (Table 2, Fig. 7). In this case, the determination of spatial coordinates X i ,Y i ,Z i set of points of the object is made using the well-known method of constructing and adjusting analytical phototriangulation, based on the use of projection centers, spatial coordinates (X Sm , Y Sm , Z Sm) which are known as reference points. [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 80-86]. The error (RMS) in determining the coordinates of the object points as a result of processing aerial photographs was (Table 2, Fig. 7):

[0136] M Xi = 0.009 m = 9 mm;

[0137] M Yi = 0.008 m = 8 mm;

[0138] M Zi = 0.007 m = 7 mm.

[0139] The listed actions were performed by two operators: a UAV operator and a robotic total station operator.

[0140] To confirm the accuracy of the results of the stated technical solution, control points were placed at the site. The coordinates of the control points were determined using a total station. The error (standard deviation) in determining the coordinates of the control points was (Table 2, Fig. 7):

[0141] M Xs = 0.005 m = 5 mm;

[0142] M Ys = 0.008 m = 8 mm;

[0143] M Zs = 0.005 m = 5 mm.

[0144] Confirmation of the accuracy of determining the spatial coordinates X i ,Y i ,Z i , obtained by the claimed solution, is carried out by comparing the values ​​of the coordinates of the control points obtained from processing aerial photographs and the values ​​of the coordinates of the control points obtained by the tachymeter.

[0145] Error (standard deviation) of spatial coordinates X i ,Y i ,Z i points of the object was (Table 2, Fig. 7):

[0146] at X coordinate: M Xi = 0.008 m = 8 mm;

[0147] by Y coordinate: M Yi = 0.008 m = 8 mm;

[0148] by Z coordinate: M Zi = 0.007 m = 7 mm.

[0149] Example 2. Determination of the spatial position of an unmanned aerial vehicle for determining the spatial coordinates of object points from the processing of images obtained from an unmanned aerial vehicle, automatic control of a UAV

[0150] • A robotic total station (Trimble S8) was installed on the site to be surveyed. This ensured direct line of sight to the UAV during the aerial survey. The site being photographed was a 50 m2 area. 2 , on the surface of which reference and control points are created. Specifications of the theodolite: angle measurement accuracy of 0.5" arc seconds, distance measurement accuracy of 4 mm + 2 mm / km [file: / / / Users / Vladimir / Downloads / trimble-s8-lr.pdf].

[0151] • Synchronized the clock of the robotic total station and the UAV clock.

[0152] A reflective prism (triple prism) 360° Leica GRZ101 (Fig. 5, Fig. 6, Fig. 7) was installed on a multicopter UAV (DJI Matrice 300) in such a way as to enable its tracking by a robotic total station without interrupting this process when the UAV turns, when the UAV enters the next flight route and other maneuvers of the UAV determined by the conditions of aerial photography of the object.

[0153] The reflective prism was attached to the UAV using a universal (multifunctional) device (Fig. 5). The levers for attaching to the external device 5, equipped with anti-slip rubber 9, were attached to the UAV using the handle of the tightening screw 8. The reflective prism was attached to lever 6 of the universal (multifunctional) device using screw 7. Lever 6 and the reflective prism (fastened with screw 7) were set in a position that ensures tracking of the reflective prism by the robotic total station and determination of the spatial coordinates of the reflective prism by the robotic total station during the movement of the UAV. The position of lever 6 and the reflective prism was fixed using locking plate 10 and the handle of screw 11 of the locking plate.

[0154] We measured the position of the front nodal point of the camera lens relative to the center of the reflective prism, i.e. determined the reduction parameters ΔX1, ΔY1, ΔZ1 with an accuracy of no more than 1 millimeter:

[0155] ΔX1= 0.0mm ± 1.0mm = +0.0m ± 0.0010m;

[0156] ΔY1= +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0157] ΔZ1= +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0158] The reduction parameters are measured using a measuring instrument, namely a caliper.

[0159] • The UAV was launched into airspace, and the operator of the robotic total station pointed it at the UAV. The robotic total station found the reflective prism and focused on it, after which it began automatically tracking and determining the position (spatial coordinates) of the reflective prism. Spatial coordinates (X P , Y P , Z P ) the reflective prism of the UAV was determined in the coordinate system of the robotic total station using the software of the robotic total station, while the time t was recorded р determining the coordinates of the reflective prism.

[0160] The UAV moves along a given route at a given altitude with a given speed and takes pictures of an object with a given longitudinal and transverse overlap, while the onboard UAV system records the photographing time t m .

[0161] The UAV's flight routes were automatically controlled. There were two routes, four images per route, and eight total images. The longitudinal overlap between images was no more than 80%, and the transverse overlap (the overlap between images from adjacent routes) was 80%.

[0162] • Completed aerial photography and landed the UAV.

[0163] • After completion of the aerial survey, control measurements were taken of the position of the front nodal point of the camera lens relative to the center of the reflective prism, i.e. the reduction parameters ΔX2, ΔY2, ΔZ2 were determined with an accuracy of no more than 1 mm:

[0164] ΔX2= 0.0 mm ± 1.0 mm = +0.0 m ± 0.0010 m;

[0165] ΔY2= +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0166] ΔZ2= +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0167] The reduction parameters were measured using a caliper. The average value of the reduction parameters was calculated (using formula 1):

[0168] ΔX = 0.0 mm ± 1.0 mm = +0.0 m ± 0.0010 m;

[0169] ΔY = +56 mm ± 1.0 mm = 0.0560 m ± 0.0010 m;

[0170] ΔZ = +205.0 mm ± 1.0 mm = +0.2050 m ± 0.0010 m.

[0171] • Determined spatial coordinates X PTm , Y PTm , Z PTm reflective prism at the moments of photographing t m To calculate the X coordinates PTm , Y PTm , Z PTm time t was used р determining the coordinates of the reflective prism, using interpolation implemented in the well-known software TsFS PHOTOMOD, designed for photogrammetric processing of aerial photographs.

[0172] • Determined the coordinates of the front nodal point of the X-ray camera lens Sm , Y Sm , Z Sm at the time of shooting t m by taking into account, using formula 2, the reduction parameters (ΔX, ΔY, ΔZ), which characterize the displacement of the front nodal point of the camera lens relative to the center of the reflective prism (Table 3, Fig. 8).

[0173] • Determined the spatial coordinates X i ,Y i ,Z i set of object points from processing aerial photographs using the photogrammetric software package Agisoft Metashape (Table 4, Fig. 9). In this case, the determination of spatial coordinates X i ,Y i ,Z i set of points of the object is made using the well-known method of constructing and adjusting analytical phototriangulation, based on the use of projection centers, spatial coordinates (X Sm , Y Sm , Z Sm) which are known as reference points. [Chibunichev A. G. Photogrammetry: a textbook for universities. Moscow: Publishing house MIIGAiK, 2022. pp. 80-86]. The error (RMS) in determining the coordinates of the object points as a result of processing aerial photographs was (Table 4, Fig. 9):

[0174] M Xi = 0.008 m = 8 mm;

[0175] M Yi = 0.010 m = 10 mm;

[0176] M Zi = 0.009 m = 9 mm.

[0177] The listed actions were performed by two operators: a UAV operator and a robotic total station operator.

[0178] To confirm the accuracy of the results of the stated technical solution, control points were placed at the site. The coordinates of the control points were determined using a total station. The error (standard deviation) in determining the coordinates of the control points was (Table 4, Fig. 9):

[0179] M Xs = 0.001 m = 1 mm;

[0180] M Ys = 0.0002 m = 0.2 mm;

[0181] M Zs = 0.001 m = 1 mm.

[0182] Confirmation of the accuracy of determining the spatial coordinates X i ,Y i ,Z i , obtained by the claimed solution, is carried out by comparing the values ​​of the coordinates of the control points obtained from processing aerial photographs and the values ​​of the coordinates of the control points obtained by the tachymeter.

[0183] Error (standard deviation) of spatial coordinates X i ,Y i ,Z i points of the object was (Table 4, Fig. 9):

[0184] at X coordinate: M Xi = 0.008 m = 8 mm;

[0185] by ​​Y coordinate: M Yi = 0.010 m = 10 mm;

[0186] Z coordinate: M Zi = 0.009 m = 9 mm.

[0187] Based on the results presented, it can be concluded that the applicant has solved the identified technical problem and achieved the stated technical result:

[0188] - It is possible to determine the spatial coordinates of the points of the object under study with an error of no more than 0.015 m, i.e. a standard deviation of 15 mm, only using linear elements of external orientation, without determining the angular elements of external orientation (Table 2, Fig. 7; Table 4, Fig. 9).

[0189] - The spatial position of the UAV (i.e., the linear elements of external orientation) is determined with an error (RMS) of 0.01 m, i.e. 10 mm, using a single angle-measuring and range-finding device, namely, a robotic tachymeter (Table 1, Fig. 6; Table 3, Fig. 8). In this case, only one reflecting prism (triple prism) is installed on the UAV (Fig. 3, Fig. 5).

[0190] - The technical solution is implemented using a reflective prism (triple prism), which is mass-produced for geodetic measurements, and a universal (multifunctional) mount for the reflective prism, which allows for the quick replacement (if necessary) of the reflective prism (Fig. 3, Fig. 5).

[0191] - When replacing the lens of the shooting camera, as well as when replacing the shooting camera itself, it is not necessary to replace the reflective prism.

[0192] - It is possible (if necessary) to quickly replace one reflective prism with another.

[0193] - Determination of spatial coordinates of object points is performed without using a rangefinder and hovering of the UAV over the object.

[0194] - The labor intensity of the process of targeting a UAV and determining its spatial coordinates has been reduced by using a robotic tacheometer and a reflective prism mounted on the UAV.

[0195] - A higher technological implementation of the process of determining the spatial coordinates of a set of object points from the processing of aerial photographs of the object without using reference points on the object is ensured, which is achieved by reducing the number of measuring instruments (one instead of three), reducing the number of reflective prisms (one instead of 3) placed on the UAV, to which the measuring instruments are aimed to determine the position of the UAV.

[0196] When determining the coordinates of a UAV's reflective prism and determining the spatial coordinates of object points in the robotic total station coordinate system, there is no need to place control points on the object. This is achieved by using the projection centers of the survey camera as control points. The coordinates of the projection centers of the survey camera are calculated based on the spatial coordinates of the UAV's reflective prism and taking into account the reduction parameters characterizing the displacement of the front nodal point of the survey camera lens relative to the reflective prism center. Determining the spatial coordinates of object points from the processing of aerial photographs of the object without the use of control points is of practical importance for solving engineering and geodetic problems, especially for engineering and geodetic problems for objects where the creation of control points is impossible (electrical substations, high-rise structures, etc.).

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