RU2751575C1 - Method for estimating visibility of ground object from space - Google Patents

Abstract

FIELD: calculation.

SUBSTANCE: the invention relates to the field of countering technical reconnaissance equipment and is intended for estimation of visibility of hidden (masked) ground objects in conditions of natural and artificial masks from space-based technical imagery reconnaissance equipment. Due to calculation of the intervals of visibility of the hidden object for a certain imagery reconnaissance spacecraft based on the data on the current time, the flight path of the spacecraft, the geographical coordinates of the hidden object, and the coordinates of the non-transparent elements of the surrounding space. The coordinates of the non-transparent elements are determined by scanning the upper hemisphere of the space with a laser sensor relative to the point of location of the object on the surface of the Earth by azimuth and elevation angles. The use of laser sensors significantly reduces the time losses for estimation of visibility of the object, and the use of a digital model of the surrounding space increases the accuracy of estimation due to the possibility of using computing technology to calculate the visibility of the object from all angles of possible flyovers of reconnaissance equipment.

EFFECT: reduced time costs and increased accuracy of estimation of visibility of an object from space.

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Description

The invention relates to the field of counteraction to technical means of reconnaissance and is intended to assess the visibility of hidden (masked) ground objects in conditions of natural and artificial masks from technical means of aerial reconnaissance space-based.

At the present time, aerospace reconnaissance is one of the most informative, which includes television, thermal imaging, and radar aerial reconnaissance. They are based on the registration of electromagnetic waves of the visible, infrared, ultraviolet or radar range reflected from objects or emitted directly by objects and the construction of images of the object in real or conventional colors [2].

In turn, one of the effective methods of countering species reconnaissance is masking an object using natural and artificial masks (forest, mountains, buildings, etc.), especially in wooded areas and in urban areas [1]. Natural masks, in comparison with standard camouflage kits, have an indisputable advantage - a high camouflage ability due to the fact that they themselves are part of the natural background, and also have a high attenuation coefficient of electromagnetic waves in the ranges of these types of reconnaissance.

In order to control the quality of the masking of the object, an assessment of its visibility is carried out, which makes it possible to assess the effectiveness of the measures applied.

Known air and ground methods for assessing the visibility of an object [1].

Air control is carried out using a set of engineering reconnaissance equipment, by photographing a camouflaged object from different angles and analyzing photographs for the visibility of the hidden object against an external (underlying) background, including under natural and artificial masks. Photographing is carried out from the air using an aircraft. The disadvantages of air control are time costs, as well as the practical impossibility of shooting an object from all angles of possible flights of space-based reconnaissance means.

The closest method in technical essence - a prototype, is ground control, which is carried out similarly to air control, but from the surface of the Earth. The disadvantages of ground control are time costs, as well as low accuracy in assessing the visibility of an object, associated with restrictions on the use of the method for space reconnaissance, because control is carried out only from the surface of the Earth.

The technical result is expressed in reducing time costs and increasing the accuracy of assessing the visibility of an object from space.

The technical result is achieved by calculating the intervals of visibility of the hidden object for a certain spacecraft of the view reconnaissance on the basis of data on the current time, the flight path of this spacecraft, the geographical coordinates of the hidden object, as well as the coordinates of the opaque elements of the surrounding space. The coordinates of opaque elements are determined by scanning the upper hemisphere of space with a laser sensor relative to the point of location of the object on the Earth's surface in azimuth angles and elevation angles.

Thus, the use of laser sensors significantly reduces the time spent on assessing the visibility of an object, and the use of a digital model of the surrounding space increases the accuracy of the assessment due to the possibility of using computer technology to calculate the visibility of an object from all angles of possible spans of reconnaissance means.

The essence of the invention is illustrated by drawings.

FIG. 1. Location of the hidden object in natural masks, where

1 - hidden object, represented by a geometric point;

2 - underlying surface - Earth;

3 - natural masks (trees).

FIG. 2. Digital model of the space surrounding the hidden object, where

1 - hidden object, represented by a geometric point;

2 - underlying surface - Earth;

3 - opaque elements of the surrounding space in the form of a digital model.

FIG. 3. Moments of visibility of the hidden object relative to the flight path of the spacecraft, where

1 - hidden object, represented by a geometric point;

2 - underlying surface - Earth;

3 - natural masks (trees).

4 - flight path of the spacecraft;

A - the moment the spacecraft enters the visibility zone of the hidden object;

B - the moment the spacecraft leaves the visibility zone of the hidden object;

ΔТ is the interval of visibility of the hidden object.

An embodiment of the invention is shown in FIG. 1-3.

Suppose the hidden object 1, the visibility of which is estimated, is located on the surface of the Earth 2 under natural masks - forest 3 (Fig. 1). The hidden object, for ease of description, is represented by a geometric point.

The coordinates of the opaque elements of the surrounding space are obtained using a laser sensor, which can be a lidar that uses the phenomena of absorption and scattering of light in optically transparent media. Coordinates are calculated based on information about the geographic coordinates of the hidden object, the distance from the sensor to the opaque elements, the angles of the position of the opaque elements relative to the sensor - the azimuth and elevation angles. The laser sensor is installed in place of the hidden object. Based on the data obtained, a digital model of the space surrounding the hidden object is formed (Fig. 2).

Data on the current time and geographic coordinates of the hidden object is obtained by known methods.

Data on the flight path of the reconnaissance spacecraft can be obtained using a two-line set of TLE elements (abbr. From the English two-line element set), which is a set of elements of the Earth satellites orbit, periodically updated and posted on the Internet, for example, on the website http : //celestrak.com/NORAD/elements/. The flight trajectory of the spacecraft using a set of TLE elements can be calculated with the required accuracy using the well-known models SDP8, SGP9, etc. [3].

Thus, the calculated and obtained data make it possible to calculate the visibility interval AT of the hidden object, between the moment A of the spacecraft enters the zone of visibility of the hidden object and the moment of exit B (Fig. 3).

Sources of information

1. Korolev A.Yu., Koroleva A.A., Yakovlev A.D. Disguise of weapons, equipment and objects. - SPb: ITMO University, 2015 .-- 155 p.

2. Menshakov Yu.K. Technical reconnaissance from space. - M .: Academia, 2013 .-- 656 p .: ill.

3. SPACETRACK REPORT NO.3. Models for Propagation of NORAD Element Sets. Felix R. Hoots. Ronald L. Roehrich. December 1980.

Claims (1)

A method for assessing the visibility of a terrestrial object from space, which consists in determining the fact of visibility of a terrestrial object in conditions of natural and artificial masks, characterized in that the coordinates of opaque elements of the surrounding space are determined by scanning the upper hemisphere of space with a laser sensor relative to the point where the object is located on the Earth's surface in azimuth angles and angles of elevation, on the basis of the data obtained, as well as data on the current time, flight trajectory of at least one aerial reconnaissance spacecraft, geographic coordinates of the hidden object, the intervals of visibility of the hidden object for the given reconnaissance spacecraft are calculated.

Images