RU2296343C1 - Mode of detection of an object - Google Patents

Abstract

FIELD: the invention refers to radiolocation.

SUBSTANCE: it is directed on provision of possibility of realization of a monostatic variant of building a radar system and removal of an interference factor conditioned by diffraction of radar signal on the sought object. The indicated technical result is achieved due to the fact that in the mode of detection of an object including radiation of an electromagnetic signal reflected from the object and from a diffuser located behind the location place of the object into the zone of observation the decision making about detection of the object the reception of a signal formed in the reception place in the shape of an interference picture is executed as a result of adding of the signal reflected from the object and of the signal reflected from the diffuser. At that the duration of the radiation of the signal is chosen starting from demand about simultaneous presence of the mentioned reflected signals in the reception place which can be as spaced so as combined with the radiation place and the decision about detection of the object is taken according to the fact of the availability of the mentioned interference picture.

EFFECT: provides possibility of realization of a monostatic variant of a radar system.

Description

The invention relates to radar and can be used to detect various objects located in the observation zone.

Known methods for detecting objects, which include radar-searching for the sought-after objects with the analysis of the received interference signal, which is realized by emitting an electromagnetic signal into the observation zone, receiving a signal and deciding whether to detect an object in the observation zone as a result of analyzing the received interference electromagnetic signal (see RF patent №2124220, IPC G 01 S 13/06, priority from 10.29.1997, RF patent No. 2195683, IPC G 01 S 3/72, G 01 S 3/74, priority from 12.28.2000, RF patent No. 2133480, IPC G 01 S 3/72, G 01 S 7/42, priority from 02.0 2.1998 g.).

Of the known, the closest in technical essence is the method of detecting an object "in the light" (see RF patent No. 2133480, IPC G 01 S 3/72, G 01 S 7/42, priority dated 02.02.1998), which consists in bistatic radar of objects in the observation zone by irradiating such a zone with an electromagnetic signal, which is reflected by a scatterer located behind the estimated location of the object, while emitting a second signal scattered by the object, receiving an electromagnetic signal and a second signal, determining the interference signal the amount arising from the addition of the electromagnetic signal and the second signal, and the decision to detect the object in the observation area for the analysis of the interference signal.

The disadvantage of this method of detecting an object is the mandatory diversity of the structure of the radar system (bistatic, on-off radar arrangement), which is due to the need to take into account the interference (for this method) factor - diffraction of the electromagnetic signal due to the interaction of the electromagnetic signal with the irradiated object. In addition, for this method, when objects are detected, double diffraction of the electromagnetic signal is possible on the irradiated object (on the beam "emitter-scatterer" and on the beam "diffuser-receiver"). Such double diffraction is also a hindrance that impedes the detection of desired objects. At the same time, bistatic radar is associated with obvious technical difficulties in practical implementation due to the spaced arrangement of radiation and signal reception devices. In addition, the radar algorithm includes radiation and reception of the second signal, which greatly complicates the technical performance of the radiating element of the radar and, accordingly, complicates the practical implementation of this method of radar.

The task to which the proposed technical solution is directed is to provide the possibility of realizing a monostatic version of the radar system, as well as eliminating the interference factor caused by diffraction of the radar signal at the desired object.

The technical result is expressed in the possibility of simplifying the radar system due to the implementation of a monostatic version of its construction, as well as in increasing the reliability of the location of objects by eliminating the interference factor (when analyzing the received signal) caused by diffraction of the radar signal at the desired object.

The result is achieved in that in the method of detecting an object, including radiation in the observation zone of an electromagnetic signal reflected from the object and from the diffuser located behind the location of the object, and making a decision on the detection of the object, the signal is generated, which is generated at the receiving site in the form of an interference pattern , as a result of adding the signal reflected from the object and the signal reflected from the scatterer, while the duration of the emitted signal is selected based on the requirement of simultaneous the presence of the aforementioned reflected signals at the receiving location, which can be either spaced apart or combined with the radiation location, and the decision to detect an object is made upon the presence of the mentioned interference pattern.

At the filing date of the application materials, the authors do not know the technical solution, the set of essential distinguishing features of which coincides with the claimed one.

Object detection is as follows.

The observation area is irradiated (scanned) with an electromagnetic (radar) signal, which is reflected from a diffuser located (in the case of using scatterers of natural origin, for example, tropospheric inhomogeneities) or located (in the case of using scatterers of artificial origin, for example, a radio holographic antenna made in accordance with the patent of the Russian Federation No. 2099880, IPC N 04 B 7/22, BI No. 35, 1997) for the alleged location of the desired object. The named dispersion is carried out, including, in the direction of the emitter, which allows the use of a monostatic version of the location of the radar station.

In the absence of an object in the observation zone, the radar receives only a scattered electromagnetic signal without the formation of any interference pattern. That is, the absence of the interference pattern received by the radar indicates the absence of an object in the observation zone.

In the case of the presence of an object in the observation zone, the electromagnetic signal interacts (when scanning the corresponding amount of space in the observation zone in which the desired object is located) with the object, scattering on it (regardless of the EPR of the object), including in the direction of the emitter, defined as "signal reflected from the object." Further, the electromagnetic signal propagates in space before reflection on the diffuser located behind the location of the object (including in the direction of the emitter, which is defined as "signal reflected from the diffuser"). Due to scattering (reflection) in the direction of the emitter, the reflected signals are added in space (at the receiving location) when propagating in the direction of the emitter (receiver), which forms an interference pattern at the receiving location. Fixing the above interference pattern entails a decision to detect an object in the observation zone.

The electromagnetic signal should have a duration sufficient to ensure the simultaneous presence at the receiving site of the signal reflected from the object (when such an object is in the volume of the observation zone closest to the emitter) and the signal reflected from the scatterer. That is, the duration of the emitted electromagnetic signal should not be less than the travel time of the signal doubled the distance of the object-scatterer under the above conditions. This provides the possibility of spatial addition of the mentioned reflected signals and, accordingly, the formation of the interference pattern at the receiving site.

In this case, the interference pattern may be spatial in nature (which, in this case, entails the need for its fixation on the antenna array, consisting of independent elements). The interference component of this picture is, in this case, the result of signal diffraction, the presence of which allows spatial addition (required for the manifestation of interference and the formation of an interference picture - see, for example, the article “Wave Interference”, p. 285. A new illustrated encyclopedic dictionary. - M .: Big Russian Encyclopedia, 2000) fields of the electromagnetic signal with the field of the second signal (arising on the irradiated object, in particular, as boundary or boundary waves, see, e.g. Mermer, p. 80 of the article by Newman E.Kh., Marefka R.J. Review of works on the method of moments and uniform theory of diffraction conducted at the University of Ohio // TIIER. - 1989. - T. 77. - No. 5, Thematic issue "Effective reflection area of complex radar objects", p.76-85). Thus, the interference factor is eliminated - the diffraction of the electromagnetic signal on the irradiated object. Moreover, diffraction of the electromagnetic signal is used to form an interference pattern at the receiving site.

Given the possibility of double diffraction of the electromagnetic signal on the irradiated object (when propagating along the path "emitter-scatterer" and along the path "scatterer-receiver", in the case of monostatic radar construction, at speeds (time) of moving the object less than the propagation time of the electromagnetic signal along the path " object-diffuser-object "), it should be noted that such diffraction is also not an interfering factor for the considered radar method. Moreover, double diffraction provides the possibility of radar detection of objects regardless of the ESR value inherent in them, since double diffraction involves both the lower and upper hemispheres of the irradiated object.

According to the described method for detecting objects, it is possible to monostatically build a radar system, and the interference factor in the process of detecting an object due to diffraction (or double diffraction) of the radar signal at the desired object is eliminated. This interference factor in the described method for detecting objects is used as additional support for the formation of an interference pattern, which increases the reliability of deciding on the presence of an object in the observation zone.

This method of object detection was developed with the support of the Russian Foundation for Basic Research (grant No. 05-02-08106).

Claims (1)

A method for detecting an object, including radiation in the observation zone of an electromagnetic signal reflected from the object and from the diffuser located behind the location of the object, and making a decision on detecting the object, characterized in that they receive a signal generated at the receiving site as an interference pattern as a result the addition of the signal reflected from the object and the signal reflected from the scatterer, while the duration of the emitted signal is selected based on the requirement of the simultaneous presence of removed reflected signals at the receiving site, which can be either spaced apart or combined with the radiation site, and the decision to detect an object is made upon the presence of the mentioned interference pattern.