RU2795344C1 - Method for selecting a safe landing area - Google Patents

Abstract

FIELD: aircraft.

SUBSTANCE: method for selecting a safe landing zone for an aircraft (AC). To select a safe landing zone, using one or more three-dimensional (3D) sensors installed on an aircraft (AC), a three-dimensional point cloud characterizing the space under the AC is obtained and converted into a set of flat cells describing the surfaces of objects and the terrain, while the points from the point cloud that do not belong to any surface, are excluded from the point cloud, search for obstacles among the set of cells, for each cell that is not defined as an obstacle, form the proposed landing area based on the current cell, determine the surface flatness of the proposed landing area, determine the angle slope of the proposed landing area, determine the distance of the current cell from obstacles, assign the current cell a landing safety level in accordance with the previously obtained data, and select a landing zone based on the landing safety level of the cells.

EFFECT: increased safety of aircraft landing.

10 cl, 2 dwg

Description

The field of technology to which the invention belongs

The invention relates to the field of aircraft control, and more specifically, to a method for selecting a safe landing zone for an aircraft.

State of the art

Unmanned aerial vehicles (UAVs, UAVs) are gradually becoming a part of everyday life - they carry out cargo delivery, various studies, analysis of the surrounding space, territory monitoring, object control, photo and video shooting, are used in rescue operations and find many other applications. As is the case with other modes of transport, developments are underway around the world aimed at fully automating the operation of UAVs.

One of the tasks of UAV automation is its autonomous landing. Many different methods are known from the prior art, which can be divided into 2 groups: landing on a prepared surface - for example, on a landing site, and on an unprepared surface - for example, on the ground.

Landing on the surface of the earth is often unpredictable and difficult, but from time to time situations may arise when, in order to avoid the loss of valuable cargo or the aircraft itself, it is necessary to resort to this method.

Known methods (see, for example, patent RU 2725640 C1 dated 07/03/2020) do not provide sufficient accuracy in determining the area in which landing should be performed in difficult environmental conditions or if the aircraft is equipped with inexpensive equipment with limited capabilities. This negatively affects flight safety, including the safety of cargo, aircraft, people, animals, objects in the landing zone, etc.

Thus, there is a need in the art for a method that would enable emergency landing of UAVs in a wide range of environmental conditions and would be accessible to UAVs with limited capabilities.

The essence of the invention

The present invention is directed to the creation of methods and devices to eliminate at least some of the above disadvantages of the prior art.

In particular, a method is proposed for selecting a safe landing area, comprising the steps of:

using one or more three-dimensional (3D) sensors installed on an aircraft (LA), a three-dimensional point cloud is obtained that characterizes the space under the aircraft;

converting the point cloud into a set of flat cells describing the surfaces of objects and the terrain, while points from the point cloud that do not belong to any surface are excluded from the point cloud;

search for obstacles among the set of cells;

for each cell that is not defined as an obstacle, perform the steps in which:

- form the proposed landing area based on the current cell,

- determine the evenness of the surface of the proposed landing area,

- determine the angle of inclination of the proposed landing area,

- determine the distance of the current cell from obstacles,

- assigning a landing safety level to the current cell in accordance with the distance of the current cell from obstacles, as well as in accordance with the surface evenness index and the inclination angle of the proposed landing area formed on the basis of the current cell; And

selecting a landing zone based on the safety level of landing cells.

In one embodiment, the intended landing area is an area where an aircraft can land or an area where an aircraft can place cargo;

wherein the method further comprises the step of landing and/or placing cargo in the selected landing zone.

In one embodiment, generating a proposed landing area based on the current cell comprises the steps of:

determine the size and shape of the cell; And

if the dimensions and shape of the cell allow the area required for landing to be entered into it, the current cell is determined as the intended landing area.

In one embodiment, generating a proposed landing area based on the current cell further comprises the steps of:

if the size and shape of the cell do not allow the area required for landing to be entered into it, an attempt is made to obtain an enlarged cell by combining the current cell with all cells with which it has a common border, except for the cells defined as an obstacle, while enlargement is performed until , until the limit of enlargement is reached or until an enlarged cell is obtained that satisfies the following conditions: the dimensions and shape of the enlarged cell allow you to enter into it the area necessary for landing, using at least a part of the current cell;

if the enlargement is successful, defining the enlarged cell as the intended landing area; And

if the enlargement fails, define the current cell as an obstacle.

In one embodiment, performing an obstacle search among a set of cells comprises the steps where, for each cell:

determine the coordinates and the angle of inclination of the cell relative to the X and Y axes; And

if the angle of inclination and the height of the projection of the cell on the vertical plane simultaneously exceed the allowable limits of the angle of inclination and height, the cell is defined as an obstacle.

In one embodiment, the transformation of a point cloud into a set of cells is performed by the walking cube method or the double contour method, partially or completely restoring surface defects present in the point cloud, or by random sampling consensus.

In one embodiment, the method further comprises the step of:

determine the height of the proposed landing area;

at the same time, a landing zone is selected additionally based on the height of the intended landing area.

In one embodiment, the method further comprises the steps of:

determine that an emergency has occurred; And

determining an emergency rank based on the type of emergency that occurred.

In one embodiment, the method further comprises the step of:

estimate the time available for landing, depending on the rank of the emergency;

wherein the landing area is further selected based on the time available for landing.

In one embodiment, the method further comprises the steps of:

determining whether an emergency cargo release is required based on predetermined emergency cargo release conditions and an emergency rank; And

perform emergency cargo release, if required.

Technical result

The present invention improves the efficiency of devices, systems and methods for landing an aircraft (LA). This provides:

- improving accuracy, including under difficult environmental conditions;

- reduced requirements for the characteristics of aircraft sensors;

- improving flight safety, including the safety of cargo, aircraft, people, animals, objects in the landing zone, etc.

These and other advantages of the present invention will become apparent upon reading the following detailed description with reference to the accompanying drawings.

Brief description of the drawings

On FIG. 1 shows a block diagram of the proposed method.

On FIG. 2 shows an example of marking cells for selecting a landing zone.

Detailed description

As a UAV for the purposes of the present invention, for example, a drone, a quadrocopter, a multicopter, an unmanned helicopter, a vertical take-off and landing aircraft (VTOL) or any other aircraft on which the equipment necessary to perform the proposed way.

An unmanned aerial vehicle (UAV) may contain a body, propellers, engines, a landing gear, an engine control module, a flight controller, a transceiver, a navigation module, an energy source, a camera, a set of sensors. The specific set of UAV elements and their arrangement are not limited by the present invention.

The following description will refer to UAVs for convenience, however, it should be understood that the present invention may be applied to manned aircraft if necessary. In addition, a remotely piloted aircraft may be used. Preferably, the aircraft (LA) has the ability to temporarily hover in one position in space.

The UAV can carry cargo, performing, for example, a delivery function. In another embodiment, the UAV can perform other functions, without carrying cargo.

During the UAV flight mission, an emergency situation may occur - for example, the signal from the operator or the communication signal with the base station may be lost, noisy or distorted, a navigation error may occur or the navigation system may fail, the battery charge or fuel supply may drop to a threshold value, damage may occur (for example, 1 engine may not work due to a collision with an obstacle), etc.

Having determined that an emergency situation has arisen, in order to avoid the loss of valuable cargo or the aircraft itself, the UAV control unit (for example, a flight controller or other computing unit installed on the UAV) can decide - independently or with the participation of the operator (if possible) - about the need for an emergency landing.

Having decided on the need for an emergency landing, in the simplest case, the UAV can land simply down, however, this approach can be dangerous for the cargo, the aircraft, people, animals, objects in the landing zone, etc. Accordingly, it is required to choose a landing zone that is optimal from the point of view of minimizing the danger.

How to select a safe landing zone

Next, with reference to FIG. 1, a method 100 for selecting a safe landing zone according to the present invention will be described.

At step 110, using one or more 3D sensors installed on the UAV, a three-dimensional point cloud characterizing the space under the UAV is obtained. As a 3D sensor, for example, a lidar or a depth camera can be used, which scans the space under the UAV and produces a three-dimensional point cloud. In the preferred embodiment, during the scanning of space, the UAV hangs in one position.

Next, at step 120, using the above control unit, the resulting point cloud is converted into a set of flat cells describing the surfaces of objects and the terrain that fell into the field of view of 3D sensors and, accordingly, into a point cloud. Those points from the point cloud that ultimately will not be assigned to any cell (that is, not belonging to any surface) are excluded from consideration as noise. The resulting cells are triangles, quadrilaterals, or other flat polygons covering the surfaces of objects, the earth's surface, the water surface, and so on.

Next, at step 130, the control unit searches for obstacles among the set of cells. For example, some surfaces may represent objects such as trees, poles, people, and so on. Cells assigned to these objects are defined as an obstacle. In addition, these cells can be assigned a landing safety level indicating the impossibility of landing in this cell.

Then, each cell that is not defined as an obstacle, using the control unit at step 140, is assigned a landing safety level. In particular, at step 141, a proposed landing area is formed based on the current cell, at step 142, the surface flatness of the proposed landing area is determined, at step 143, the angle of inclination of the proposed landing area is determined, at step 144, the distance of the current cell from obstacles is determined, and at step 145, landing safety level in the current cell in accordance with the distance of the current cell from obstacles, as well as in accordance with the surface evenness index and the slope angle of the proposed landing area, formed on the basis of the current cell.

Thereafter, at step 150, a landing area is selected by the control unit based on the landing safety levels assigned to the cells in the set of cells.

Ultimately, at step 160, with the help of the control unit and / or the flight controller, control actions are formed on the actuators of the UAV so that the UAV approaches the landing zone based on the received data. As it approaches, when the UAV has made some next movement towards the landing area, the UAV may again repeat steps S110-S150, performing space scanning, updating the environment, refining the landing area, and moving closer to it. Ultimately, after completing the required number of iterations, the UAV makes an autonomous landing with increased accuracy and safety in the selected landing area.

It should be noted that the intended landing area may be an area in which the UAV can land, or an area in which the UAV can place cargo. In particular, this is relevant for cases when direct landing in the landing area immediately with the cargo is impossible (for example, the cargo is suspended on a winch and will not allow the UAV to land) or when the release of the cargo will allow the UAV to gain time, return to the base station, etc. Accordingly, at step 160, the UAV may land itself or place cargo in the selected landing zone. In addition, the UAV can first select a landing zone for the cargo, place the cargo in it, then (or simultaneously with the selection of the landing zone for the cargo) select the landing zone for itself and perform an independent landing. In this case, the UAV will save both the cargo and itself, and at the same time ensure the safety of surrounding objects, people and animals.

Next, the proposed method will be described in more detail.

The conversion of a point cloud to a set of cells at step 120 can be performed in various ways. In this case, for example, using the walking cube method or the double contour method, it is possible to partially or completely restore surface defects present in the point cloud, which improves the quality of transformation and the accuracy of surface recognition. The use of the random sampling consensus method, due to its resistance to the noisiness of the initial data, makes it possible to apply the proposed method even under conditions of a highly noisy point cloud, with a low point density, with accelerated scanning, with only an inexpensive low-performance lidar, with vibrations, with external electronic measures. countermeasures, under adverse environmental conditions, etc. To speed up the conversion, the minimum allowable cell size can be set so that excessive surface detailing does not occur. The minimum allowable cell size may correspond to the minimum size of an object that can be considered an obstacle.

The search for obstacles among the set of cells at step 130 may be performed as follows. The coordinates and the angle of inclination of each cell relative to the X and Y axes are determined, and if the angle of inclination and the height of the projection of the cell on the vertical plane simultaneously exceed the allowable limits of the angle of inclination and height, the cell is defined as an obstacle. For example, a cell is a wide, high, flat wall of a building or a narrow, elongated part of a lamppost. Having determined that this cell has a vertical slope and a large height, the control unit will classify such a cell as an obstacle. In another embodiment, the cell may have a vertical or near-vertical slope, but may have such a low height that landing on such a cell, although not preferred, can be performed if the surrounding surface is sufficiently horizontal and has a sufficient size for landing - respectively , the cell itself will not be classified as an obstacle. Other combinations of cell size and inclination are also possible in which landing is possible or impossible. The boundary between such combinations is proposed to be pre-set using threshold values for the angle of inclination and height of the cell, or using an appropriate function. In this way, a simplified but sufficiently accurate way of finding obstacles is provided.

The formation of the proposed landing area based on the current cell at step 141 may be performed as follows. First, the dimensions and shape of the cell are determined, and if the dimensions and shape of the cell allow the area required for planting to be entered into it, the current cell is determined as the intended landing area. For example, if the landing requires a circular area with a diameter of 80 cm, try to fit a circle with a diameter of 80 cm into the cell, and if this can be done, determine the current cell as the intended landing area.

If the size and shape of the cell do not allow the area required for landing to be entered into it, an attempt is made to obtain an enlarged cell by combining the current cell with all cells with which it has a common border, except for the cells defined as an obstacle. For example, a cell is a triangle with sides of 5x3x10 cm. Obviously, a UAV cannot land directly into such a cell. This cell is combined with neighboring ones and a new, enlarged cell is obtained in the form of a quadrangle with sides of 80x80 cm. It is already possible to enter the required circle with a diameter of 80 cm into such an enlarged cell, and it is determined as the intended landing area.

Enlargement is performed until the limit of the enlargement possibility is reached or until an enlarged cell is obtained that satisfies the following conditions: the dimensions and shape of the enlarged cell allow the area required for landing to be entered into it, using at least a part of the current cell. For example, the current cell is a narrow horizontal surface of one ladder or a leaf on a tree. It is impossible to land on them, so enlargement is required. By itself, such a cell was not previously defined as an obstacle due to its angle of inclination and / or size, but an attempt to attach other cells to it fails, since there are no suitable cells around it with which it could be combined (in the case of a ladder) , or there are no cells at all (in the case of a leaf, which is defined as a cell "hanging in the air"), which automatically makes this cell also an obstacle. In another example, the cell is a small triangle on the sidewalk at the corner between a building wall and a staircase, or between two trees. This cell has neighboring horizontal cells, and as these cells are attached, a new enlarged cell is formed, into which the required circle with a diameter of 80 cm can be entered, but this circle does not affect the very corner triangular cell that served as the beginning for this enlarged cell. Accordingly, with the participation of that corner triangular cell, it is impossible to land, and it is also marked as an obstacle, so that when checking other cells, it would not be senselessly attached. Thus, an increased accuracy of the formation of the intended landing area is provided, which makes it possible to increase the accuracy of choosing a safe landing zone.

The surface evenness of the intended fit area in step 142 can be determined by various methods known to those skilled in the art, such as root mean square roughness (RMSH) method, roughness factor calculation, and so on.

The angle of inclination of the proposed landing area at step 143 can be determined from the boundaries of the desired landing area that has been inscribed in this proposed landing area. This is due to the fact that in each specific case, the current one cell that forms the proposed landing area, or the enlarged cell that forms the proposed landing area, can have an arbitrary shape with arbitrary boundaries, and also have significant outliers in one direction or another, and take into account each such shape and size is impractical, because only the area in which the landing will be performed is of immediate importance. Thus, increased accuracy in selecting a safe landing zone is provided.

The calculation of the distance of the current cell from obstacles in step 144 is performed, for example, from the center of the cell (to increase the speed of calculations) or as the smallest distance from each border and/or vertex of the cell (to increase the accuracy of the calculations).

Assignment of the landing safety level to the current cell at step 145 is performed in accordance with the distance of the current cell from obstacles, as well as in accordance with the surface flatness index and the slope angle of the proposed landing area formed on the basis of the current cell. In addition, it may be taken into account whether a given cell is an obstacle. As shown in the cell layout example in FIG. 2, walls, trees, bushes, etc. are marked in red (landing safety level corresponding to danger). Yellow color (medium level of landing safety) marks areas near obstacles, uneven ground, etc. Green color (landing safety level corresponding to the safest landing) marks flat horizontal zones suitable for landing. Thus, increased accuracy in selecting a safe landing zone is provided. If there are no additional factors influencing the decision, the zone closest to the UAV, consisting of green cells, is selected for landing.

In order to avoid landing on rooftops of buildings and other surfaces located significantly above the ground, the method may further comprise determining the height of the intended landing area, and the selection of the landing zone may take into account the height of the intended landing area. Thus, when further searching for an autonomously landed UAV, there will be no need to examine the roofs of buildings.

In one embodiment, when it is determined that an emergency has occurred, the UAV control unit may determine an emergency rank based on the type of emergency that has occurred. For example, if the type of emergency is loss of operator signal or navigation error, and there are no other factors, then the emergency rank can be defined as “no threat”. If the emergency type is low battery, then the emergency rank can be defined as "medium threat". If the type of emergency is the presence of damage to the UAV itself, then the rank of the emergency can be defined as “high level of threat”. It should be understood that these examples are illustrative only and do not limit the present invention. In other specific implementations, there may be other types and ranks of emergency.

Depending on the rank of the emergency, the time available for landing can be estimated, and this time can be taken into account when choosing a landing zone. For example, if the emergency rank indicates that there is no threat, the time available for landing can be estimated as unlimited, and a green zone on the surface of the earth relatively far from the UAV, which requires a relatively long flight time, can be chosen for landing. If the emergency rank, on the contrary, indicates a high level of threat, the nearest zone, one way or another suitable for landing, can be selected, even if it is a yellow zone on the roof of a building. These approaches make it possible to adapt the method to different emergency situations and to increase as much as possible the probability of saving (or reducing the probability of loss) of the cargo and the UAV itself.

In yet another embodiment, the UAV control unit may determine if an emergency payload is required based on predefined emergency payload conditions and the emergency rank, and the UAV can perform an emergency payload if required. This approach makes it possible to adapt the method to different emergency situations and to increase as much as possible the probability of saving (or reducing the probability of loss) of the cargo and the UAV itself. For example, if the value of the cargo is higher than the value of the UAV, the main efforts can be directed to the safest possible landing of the cargo. If the value of the cargo is not so great, and there is a need to save at least the UAV itself, the cargo can be urgently dropped without approaching the ground (for example, the cable holding the cargo can be automatically cut) and regardless of the security level of the cell over which at the moment UAV is located. Other intermediate scenarios are also possible, in which the decision to release can be made depending on a combination of conditions: the rank of emergency and predefined conditions for an emergency release of cargo. In one embodiment, the emergency release may still take into account the safety level of the cell so that the load does not fall from a height on a person, on a cow, on a tractor, etc.

Example

A typical commercial DJI UAV is equipped with an inexpensive low-performance lidar. As a result of signal loss from the operator in difficult environmental conditions (fog), the UAV control unit integrated into the flight controller decides on an emergency landing. With the help of lidar, a noisy three-dimensional point cloud is obtained that characterizes the space under the UAV. The point cloud is converted to a set of flat cells by random sampling consensus, with many points defined as noise from discarded. They search for obstacles among a set of cells, as indicated above - in particular, they immediately determine cells on the walls, tree trunks and bushes as obstacles. Next, for each cell that is not defined as an obstacle, a proposed landing area is formed, the surface evenness of the proposed landing area is determined, the angle of inclination of the proposed landing area is determined, the distance of the current cell from the obstacles is determined, the landing safety level is assigned to the current cell in accordance with the distance of the current cell from obstacles, as well as in accordance with the index of surface evenness and the angle of inclination of the proposed landing area, formed on the basis of the current cell. In particular, as shown in FIG. 2, mark the cells in red, yellow and green, depending on the availability and safety of the landing. After that, the nearest landing area is selected among the green cells and a safe landing is performed, keeping the UAV.

Application

Devices and methods according to the present invention can be used for autonomous landing of UAVs, performing, in particular, the delivery of goods, various studies, analysis of the surrounding space, control of objects, photo and video filming, rescue operations, autonomous monitoring for the tasks of protecting farmland, cartography, remote chemical - physical analysis, control of germination and ripeness of the crop, chemical treatment, etc. Also, if necessary, it is possible to apply the present invention in manned aircraft.

Additional Implementation Features

Various illustrative blocks and modules described in connection with the disclosure herein may be implemented or executed by a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device (PLD), discrete logic element or transistor logic, discrete hardware components, or any combination of the foregoing, designed to perform the functions described in this document. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (eg, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors together with a DSP core, or any other similar configuration).

Some blocks or modules, individually or collectively, may be, for example, a processor that is configured to call and execute computer programs from memory to perform method steps or functions of blocks or modules in accordance with embodiments of the present invention. According to embodiments, the device may further include a memory. The processor may call and execute computer programs from memory to execute the method. The memory may be a separate device independent of the processor or may be integrated with the processor. The memory may store code, instructions, commands, and/or data for execution on a set of one or more processors of the device described. Codes, instructions, commands may direct the processor to perform the steps of a method or device function.

The functions described in this document may be implemented in hardware, software running on one or more processors, firmware, or any combination of the foregoing, as applicable. The hardware and software implementing the functions may also be physically located in different locations, including such a distribution that parts of the functions are implemented in different physical locations, that is, distributed processing or distributed computing may be performed.

The above memory may be volatile or non-volatile memory, or may include both volatile and non-volatile memory. One of ordinary skill in the art will also understand that when referring to memory and storage of data, programs, codes, instructions, instructions, and the like, it is understood that there is a machine-readable (or computer-readable, processor-readable) storage medium. A computer-readable storage medium can be any available medium that can be used to carry or store a desired piece of program code in the form of instructions or data structures, and that can be accessed by a computer, processor, or other general purpose or special purpose processing device. .

It should be understood that although terms such as "first", "second", "third" and the like may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, areas, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section may be referred to as a second element, component, region, layer, or section without departing from the scope of the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the respective listed entries. Elements mentioned in the singular do not exclude the plurality of elements, unless otherwise specified.

The functionality of an element specified in the description or claims as a single element may be practiced by means of several components of the device, and conversely, the functionality of elements indicated in the description or claims as several separate elements may be practiced by means of a single component.

Although the exemplary embodiments have been described in detail and shown in the accompanying drawings, it should be understood that such embodiments are illustrative only and are not intended to limit the present invention, and that the present invention should not be limited to the particular arrangements and structures shown and described, since a person skilled in the art on the basis of the information set forth in the description and the knowledge of the prior art may be obvious various other modifications and embodiments of the invention, without going beyond the essence and scope of this invention.

Claims (36)

1. A method for selecting a safe landing zone, comprising the steps of: using one or more three-dimensional (3D) sensors installed on an aircraft (LA), a three-dimensional point cloud is obtained that characterizes the space under the aircraft; converting the point cloud into a set of flat cells describing the surfaces of objects and the terrain, while points from the point cloud that do not belong to any surface are excluded from the point cloud; search for obstacles among the set of cells; for each cell that is not defined as an obstacle, perform the steps in which: - form the proposed landing area based on the current cell, - determine the evenness of the surface of the proposed landing area, - determine the angle of inclination of the proposed landing area, - determine the distance of the current cell from obstacles, - assigning a landing safety level to the current cell in accordance with the distance of the current cell from obstacles, as well as in accordance with the surface evenness index and the inclination angle of the proposed landing area formed on the basis of the current cell; And selecting a landing zone based on the safety level of landing cells. 2. The method according to p. 1, in which the intended landing area is the area in which the aircraft can land, or the area in which the aircraft can place the cargo; wherein the method further comprises the step of landing and/or placing cargo in the selected landing zone. 3. The method according to claim. 1, in which the formation of the proposed landing area based on the current cell includes the steps of: determine the size and shape of the cell; And if the dimensions and shape of the cell allow the area required for landing to be entered into it, the current cell is determined as the intended landing area. 4. The method of claim 3, wherein generating a proposed landing area based on the current cell further comprises the steps of: if the size and shape of the cell do not allow the area required for landing to be entered into it, an attempt is made to obtain an enlarged cell by combining the current cell with all cells with which it has a common border, except for the cells defined as an obstacle, while enlargement is performed until , until the limit of enlargement is reached or until an enlarged cell is obtained that satisfies the following conditions: the dimensions and shape of the enlarged cell allow you to enter into it the area necessary for landing, using at least a part of the current cell; if the enlargement is successful, defining the enlarged cell as the intended landing area; And if the enlargement fails, define the current cell as an obstacle. 5. The method of claim 1, wherein performing an obstacle search among a set of cells comprises the steps of, for each cell: determine the coordinates and the angle of inclination of the cell relative to the X and Y axes; And if the angle of inclination and the height of the projection of the cell on the vertical plane simultaneously exceed the allowable limits of the angle of inclination and height, the cell is defined as an obstacle. 6. The method according to claim 1, in which the transformation of the point cloud into a set of cells is performed by the walking cube method or the double contour method, partially or completely restoring surface defects present in the point cloud, or by random sampling consensus. 7. The method according to claim 1, further comprising the step of: determine the height of the proposed landing area; at the same time, the landing zone is selected additionally based on the height of the proposed landing area. 8. The method according to claim 1, further comprising the steps of: determine that an emergency has occurred; And determining an emergency rank based on the type of emergency that occurred. 9. The method of claim 8, further comprising the step of: estimate the time available for landing, depending on the rank of the emergency; wherein the landing zone is further selected based on the time available for landing. 10. The method of claim 8, further comprising the steps of: determining whether an emergency cargo release is required based on predetermined emergency cargo release conditions and an emergency rank; And perform emergency cargo release, if required.

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