WO2021122361A1 - Procédé et dispositif destinés à détecter une zone spatiale au moyen d'ondes radar - Google Patents

Procédé et dispositif destinés à détecter une zone spatiale au moyen d'ondes radar Download PDF

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Publication number
WO2021122361A1
WO2021122361A1 PCT/EP2020/085711 EP2020085711W WO2021122361A1 WO 2021122361 A1 WO2021122361 A1 WO 2021122361A1 EP 2020085711 W EP2020085711 W EP 2020085711W WO 2021122361 A1 WO2021122361 A1 WO 2021122361A1
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WO
WIPO (PCT)
Prior art keywords
radar
wall
waves
ball
ghz
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PCT/EP2020/085711
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German (de)
English (en)
Inventor
Andrey OSIPOV
Original Assignee
Deutsches Zentrum für Luft- und Raumfahrt e.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Deutsches Zentrum für Luft- und Raumfahrt e.V. filed Critical Deutsches Zentrum für Luft- und Raumfahrt e.V.
Priority to EP20824530.8A priority Critical patent/EP4078727A1/fr
Publication of WO2021122361A1 publication Critical patent/WO2021122361A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/16—Reflecting surfaces; Equivalent structures curved in two dimensions, e.g. paraboloidal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/411—Identification of targets based on measurements of radar reflectivity
    • G01S7/412—Identification of targets based on measurements of radar reflectivity based on a comparison between measured values and known or stored values

Definitions

  • the invention relates to a method and a device for detecting a spatial area by means of radar waves.
  • Radar waves enable the detection and location of objects on the basis of electromagnetic waves in the short and microwave range. Location using radar waves also works when the medium between the radar transmitter and the radar target is impermeable to visible light (e.g. due to fog, clouds, smoke, darkness and the like). Radar technology is constantly being improved by technical advances in the development of radar sensors and antenna technology as well as by new computer-aided signal processing methods. New applications for radars are emerging, especially in the area of traffic (e.g. autonomous and assisted locomotion) and in the area of safety (e.g. detection of dangerous situations). The detection of a spatial area by means of radar radiation requires that the radar waves from the spatial area are reflected back with sufficient signal strength. This can be achieved with special radar reflectors that have a high Ra darcross section. The radar cross-section is a known quantity and reflects the strength of a radar target.
  • Retroreflectors are often used as radar reflectors, which largely reflect the incoming radar waves, largely regardless of the direction of incidence and the orientation of the reflector, in the direction from which they came. Such retroreflectors are designed, for example, as corner reflectors made of two or three plates that are perpendicular to one another. So-called Lüneburg lenses are also used as retroreflectors. These are spherical lenses with an inwardly increasing refractive index, which is achieved by the dielectric material with a location-dependent dielectric constant. Lüne burg lenses are characterized by the fact that radar beams incident in parallel are focused in a reflection point and reflected in the opposite direction to their direction of incidence. Lüneburg lenses are difficult to manufacture due to the variation in their dielectric constants. Furthermore, Lüneburg lenses require metallization at the point of reflection (otherwise no reflection), which significantly limits their coverage area.
  • the document DE 199 43 396 B3 describes a method for protecting moving objects by means of a deployable decoy, the folded decoys being fired by the object to be protected and deployed during the shot using gases.
  • the decoy comprises corner reflectors as radar-reflecting objects.
  • the document DE 20 2006 002 001 U1 discloses an automatic emergency rescue balloon with an internal radar reflector for marking people, objects and life rafts in the event of an emergency at sea.
  • the object of the invention is to provide a method and a device for detecting a spatial area by means of radar waves, in which simply structured radar reflectors with a high radar cross section are used.
  • a spatial area is detected by means of Ra darwellen, in that a radar device sends out radar waves in a predetermined frequency range into the spatial area and receives radar echoes from the spatial area, which result from the backscattering of the radar waves from the spatial area.
  • the radar device processes the received radar echoes in order to determine information about the spatial area.
  • Corresponding processing methods for radar echoes are known per se and will not be further explained in detail.
  • objects in the spatial area can be detected using the received radar echoes. Information on the position of these objects is determined, in particular the direction in which the object is located starting from the radar device, and / or the distance of the object from the radar device. The distance is usually determined by measuring the transit time of the radar waves.
  • the method according to the invention is characterized in that one or more spheres are installed as radar reflectors in the spatial area to be captured, each of which comprises a spherical outer wall that is partially transparent and partially reflective for the radar waves of the radar device.
  • the outer wall is designed in such a way that when it is hit by radar radiation, part of the radar radiation is transmitted and part of the radar radiation is reflected.
  • the concept of the installation of the spheres is to be understood in such a way that the spheres are dedicated by people for the purpose of reflecting radar radiation in the spatial area.
  • the outer wall is followed by a hollow area which is so large that radar beams from radar radiation from the radar device entering via the outer wall occur inside the respective sphere, twice and three times each are reflected on the outer wall and then exit opposite and parallel to the direction of incidence of the incoming radar radiation as a radar echo through the outer wall.
  • the hollow area is so large that ray paths of the respective Ra radiate, which are reflected twice and three times on the outer wall and then emerge from the sphere opposite and parallel to the direction of incidence, are permitted and not hindered.
  • the hollow area can be designed as a spherical shell.
  • the radar device receives this radar echo and detects the respective ball via this radar echo, ie information about the ball and preferably its position or distance relative to the radar device is determined.
  • the method according to the invention is based on the knowledge that partially transparent and at least partially hollow spheres are very suitable as radar reflectors.
  • these spheres due to multiple reflections on the inside of their outer wall, a significantly higher radar cross-section can be achieved compared to such hollow or solid spheres, which reflect the entire incident radar radiation and are designed, for example, as metallic spheres.
  • the spherical outer wall of the partially transparent spheres ensures that the radar cross-section of the spheres is independent of the direction of incidence of the radar waves. Due to the partially hollow interior of the corresponding balls, a weight reduction is also achieved.
  • the invention makes use of the fact that the radar cross-section of a partially transparent sphere is mainly responsible for two and three rays reflected inside the sphere. Accordingly, it is not absolutely necessary that the ball is hollow in its entire interior, but only can a section adjoining the outer wall can be designed to be hollow, as long as the beam path is not hindered by double and triple reflected radar beams. Nevertheless, in a preferred embodiment, at least one ball and preferably each of the one or more balls is a hollow ball, the hollow area of which encompasses the entire interior of the at least one ball. This creates a radar reflector with a particularly low weight.
  • the diameter of a respective sphere of the one or more spheres is larger and preferably at least 30 times larger than the largest wavelength in the predetermined frequency range of the Ra darwellen. In this way, particularly high radar cross-sections are achieved for the corresponding sphere.
  • radar waves can be transmitted into the spatial area in different frequency bands.
  • the specified frequency range of the transmitted radar waves comprises frequencies between 1 GHz and 300 GHz.
  • the specified frequency range is preferably in the frequency band between 8 GHz and 12 GHz (so-called X-band) or in the frequency range from 26.5 GHz and 40 GHz (so-called Ka-band) or in the frequency range between 75 GHz to 110 GHz (so-called . W band).
  • each special ball of the one or more balls is a floating inflated gas balloon.
  • the floating of the gas balloon can be achieved with a suitable filling of the balloon with a low density gas.
  • the gas balloon can be tied up, ie attached to an object via a fastening means (for example a leash). Nonetheless, the gas balloon can optionally also be floating freely.
  • balls designed as gas balloons has particular advantages.
  • their size and thus their reflective properties can be varied in a simple manner.
  • large ball diameters can be achieved with gas balloons, which leads to very high backscatter cross-sections.
  • each sphere of the one or more spheres is designed in such a way that its radar cross-section, averaged over the specified frequency range of the radar waves, is at least twice as large as that of a sphere with the same diameter as the respective sphere and with an outer surface , which is fully reflective for radar waves in the given frequency range (e.g. a metallic sphere).
  • the detailed description describes in detail how such balls can be realized.
  • the averaged radar cross-section of the respective sphere is preferably at least five times or possibly also ten times as large as that of a sphere with the same diameter and a fully reflective outer surface.
  • the thickness of the outer wall of a respective ball of the one or more balls is preferably 8 mm or less.
  • the frequency range of the radar waves is in the frequency band between 8 GHz and 12 GHz and the thickness of the outer wall of at least one ball and preferably each ball of the one or more balls is between 4 mm and 8 mm and in particular 6 mm .
  • the frequency range of radar waves in the frequency band between 26.5 GHz and 40 GHz and the thickness of the outer wall of at least one sphere and preferably each sphere of the one or more spheres is between 1.5 mm and 2 mm and in particular 1.7 mm. The inventor was able to determine through calculations that with the two last-mentioned embodiments a particularly high radar cross-section of the respective balls is achieved, in particular when the outer wall of the respective ball is made of rubber.
  • the backscattering properties of the balls differing, which can be achieved by using different materials for the outer wall and / or different thicknesses of the outer wall and / or different diameters of the balls .
  • the multiple spheres are preferably designed in such a way that the radar echoes of the multiple spheres result in a radar cross section which is essentially independent of the frequencies in the predetermined frequency range of the radar waves.
  • the radar cross section of the spheres used in the method according to the invention depends on the frequency of the radar radiation used.
  • the radar device uses the radar echo to detect the frequency-dependent course of the radar cross-section in the specified frequency range of the radar waves, this course in the radar device with one or more frequency-dependent courses of the radar cross-sections from one or more previously known radar reflectors (ie Radarreflek gates with a previously known structural design) in the given frequency range of the radar waves is compared to identify the respective sphere as a réelle known radar reflector, ie to determine whether a respective Ku gel corresponds to a known radar reflector.
  • the method according to the invention can be used in a large number of areas of application, in particular in the automotive sector, in aviation, in shipping, in space travel, in defense technology and in the field of security and disaster control.
  • a large number of application examples are mentioned.
  • at least some of the one or more balls are attached to one or more road traffic infrastructure elements, such as B. on delineator posts on the roadside, and / or on one or more road users in the Jardinbe to be detected rich provided, for example on motor vehicles, motorcycles, bicycles or motorcyclists or cyclists.
  • the balls can also be attached to pedestrians.
  • the radar waves can be transmitted by a radar device which is attached to a road traffic infrastructure element or a road user.
  • At least some of the one or more balls are provided on at least one flying object and / or on at least one floating object in the spatial area to be detected.
  • the flying object can, for. B. be an airplane, a helicopter, a drone, a satellite and the like.
  • the floating object can e.g. B. be a ship, a buoy, a float and the like.
  • the radar waves it is also possible for the radar waves to be emitted by a radar device which is attached to a flying object or a floating object.
  • the radar waves are emitted by a radar device that is attached to an autonomously moving object or to a person.
  • the autonomously moving object can be, for example, an agricultural vehicle (e.g. a tractor), a robot in the industrial sector, a robot in the medical environment or also a robot for private applications.
  • the robot can be a care robot, a lawnmower robot, a vacuum cleaner robot and the like.
  • the person is especially a person who is in a dangerous place Moving terrain.
  • it is also possible that at least a part of the one or more balls is provided on at least one autonomously moving object and / or on at least one person in the spatial area to be detected.
  • the invention relates to a device for detecting a spatial area by means of radar waves.
  • the device contains a radar device which is designed in such a way that, during operation, it emits radar waves in a predetermined frequency range into the spatial area and receives radar echoes from the spatial area, which result from the backscattering of the radar waves from the spatial area, the radar device also being set up for this purpose to process the received radar echoes in order to determine information about the spatial area.
  • the device comprises, as radar reflectors, one or more spheres which are installed in the spatial area, the one or more spheres each comprising a spherical outer wall which is partially transparent and partially reflective for the radar waves of the radar device.
  • a hollow area adjoins the outer wall, which is so large that radar beams from the radar device entering via the outer wall occur inside the respective sphere, which are reflected twice and three times on the outer wall and then emerge opposite and parallel to the direction of incidence of the incoming radar radiation as a radar echo through the outer wall.
  • the radar device is configured in such a way that it detects the respective sphere via this radar echo that is received from it.
  • the device according to the invention is preferably set up to carry out one or more preferred variants of the method according to the invention.
  • the invention relates to the use of one or more balls with a spherical outer wall that is partially transparent and partially reflective for radar waves, and the subsequent hollow area inside the ball as radar reflectors in the method according to the invention or in one or more preferred embodiments of the method according to the invention or in the device according to the invention or in one or more preferred variants of the device according to the invention.
  • FIG. 1 shows a schematic sectional view of a radar reflector in the form of a metallic sphere
  • FIG. 2 shows a schematic sectional view of a hollow sphere which, in a variant of the method according to the invention, is used as a radar reflector;
  • FIG. 3 is a diagram showing the frequency-dependent course of the radar cross-section of an embodiment of the hollow sphere from FIG. 2;
  • FIG. 4 is a diagram showing the radar cross-section averaged over the frequencies of radar radiation as a function of the diameters of the balls for an embodiment of a metallic ball from FIG. 1 and variants of hollow balls from FIG. 2 with different wall thicknesses;
  • FIG. 5 is a schematic sectional view of a modified embodiment of the hollow ball from FIG. 2;
  • FIG. and 6 and 7 are schematic sectional views of further embodiments from groups of several hollow spheres.
  • the embodiments of the invention described below are based on the knowledge that balls with an outer wall that is partially transparent for radar waves and adjoined by a sufficiently large hollow area inside the ball are very suitable as radar reflectors. This is due to the fact that these spheres, which are also referred to as hollow spheres in the following, have a high radar cross section.
  • Fig. 1 shows in cross section a known metallic sphere, which is only conditionally suitable for the reflection of radar radiation in comparison to the hollow spheres described below.
  • the metallic sphere is designated in Fig. 1 with the reference character G and has a metallic surface la 'which is fully reflective for incident radar radiation (i.e. essentially all of the incident radar radiation is reflected back).
  • the diameter of the ball is denoted by reference symbol D.
  • Parallel radar beams fall from a schematically indicated radar device 2 (not shown to scale) onto the surface la 'of the metallic sphere G.
  • Exemplary radar echoes RE are shown by dashed arrows from the reflection on the surface la'.
  • the radar beam RS incident vertically downwards at the north pole is shown, which leads to a radar echo RE opposite to the radar beam RS.
  • the RCS value of a metallic sphere with a diameter D which is greater than the wavelength of the incident radar radiation, is proportional small.
  • FIG. 2 An essential finding on which the invention is based is that hollow spheres that are partially transparent to radar radiation reflect much more strongly than metallic spheres of the same size in the direction of the radar device.
  • An embodiment of a corresponding partially transparent hollow sphere is shown in FIG. 2.
  • the hollow sphere is denoted by reference number 1 and is used as a radar reflector for radar radiation.
  • the radar radiation is in turn generated by a radar device 2 (not shown to scale). Due to the large distance between the radar device 2 and the sphere 1, parallel radar beams fall vertically downwards onto the hollow sphere 1.
  • the inside of the ball 1 is completely hollow, ie the inside of the ball forms a cavity 1b. This cavity is surrounded by an outer wall la with the thickness d.
  • the outer wall la is made of a material which partially transmits and partially reflects the incident radar radiation.
  • Two incident radar beams RS and RS 'of the radar radiation are indicated by way of example.
  • the portion of the radar beam RS that enters the interior of the hollow sphere 1 via its outer wall 1 a is reflected twice on the inside of the hollow sphere, as indicated by the beam path corresponding to the dashed arrows P.
  • the portion of the radar beam RS 'that enters the interior of the hollow sphere 1 is reflected three times on the inside thereof, as indicated by the beam path corresponding to the dashed arrows P'.
  • a radar beam RE emerging from the hollow sphere results from the radar beam RS
  • a radar beam RE 'emerging from the hollow sphere results from the radar beam RS'.
  • These radar beams are radar echoes, which are then recorded and evaluated by the radar device 2 in order to detect the corresponding hollow sphere. It should be noted that with each reflection of the radar beams RS and RS 'and when exiting the corresponding Radar echoes RE and RE 'from the hollow sphere due to the partial transparency of the outer wall la losses occur.
  • the RCS value of the hollow ball 1 is significantly greater than the RCS value of a comparable metallic ball, as shown in FIG. This is due to the fact that additional reflections of the radar beams occur in the interior of the sphere on its curved inner surface and are thrown back towards the radar device. The number of internal reflections of the respective radar beams is theoretically unlimited. The main contributions to the radar cross-section, however, come from two- and three-fold reflected beams, as they result from the beams RS and RS 'in Fig. 2.
  • the radar echoes thrown back in the direction of the radar device 2 cut across the outer wall la of the ball 1 along rings, whose diameter is determined by the number of reflections M of the corresponding radar rays on the inside of the outer wall la and the diameter D of the sphere.
  • the overall backscattered field from the hollow sphere 1 results from the superposition of radar beams that differ in the number of reflections.
  • the dominant radar beams with two and three reflections have roughly the same amplitudes, but different optical paths, which are dependent on the frequency of the radar radiation, the diameter D of the sphere and the thickness d of the outer wall. Therefore, the radar cross-section of a hollow sphere shows a strong dependency on the parameters mentioned above.
  • the inventor determined the frequency-dependent radar cross-sections for different materials of outer walls 1 a of the hollow sphere 1 by means of a simulation based on a known, exact analytical calculation.
  • the materials mentioned in Table 1 below namely a rubber made from natural rubber, polypropylene, Teflon and quartz glass, were analyzed.
  • FIG. 3 shows a diagram which shows the result of the inventor's calculations for a hollow ball 1 made from the rubber of Table 1 with a diameter D of 3 m and a wall thickness d of 6 mm.
  • the radar frequencies in the X-band between 8 GHz and 12 GHz are reproduced along the abscissa.
  • the radar cross-section RCS is plotted in square meters along the ordinate, which is independent of direction due to its spherical shape.
  • there is a strong frequency dependence of the RCS value for such a hollow sphere A similar frequency dependency also results for hollow spheres from the other materials mentioned in Table 1 above.
  • the diameter D of the hollow sphere is generally much greater than the wavelength of the incident radar waves.
  • the diameter is preferably 30 times greater than the longest wavelength in the corresponding frequency spectrum of the radiated radar radiation. Depending on the frequency spectrum of the radar radiation used, this results in hollow spheres with diameters from a few centimeters to several meters. Large gas balloons can, for example, have a diameter of 60 m.
  • the inventor shows RCS values in the X band from 8 GHz to 12 GHz for a hollow ball made of rubber in Table 1 with an outer wall thickness of 6 mm as a function of its diameter D.
  • rubber ball always refers to a hollow ball made from the rubber material in Table 1.
  • the sixth column of the table shows the median or mean value (Ds) of the fluctuations in the RCS value around the median value in square meters.
  • the seventh column shows the quotient (Ds) / (s) of the values from the sixth and fifth columns.
  • the weight of the corresponding hollow rubber ball is given in the last column of the table.
  • the mean RCS values (s) are significantly greater than for a comparable metallic ball.
  • the factors C 2 and C 3 depend on the nature of the outer wall of the Hohlku gel and the frequency range of the radar radiation, but not on the diameter of the hollow sphere. Table 3 below shows the values of the factors C 2 and C 3 for hollow rubber balls of different wall thickness d in the X-band. As you can see, the factors are particularly high with a wall thickness of 6 mm, which in turn leads to very high RCS values.
  • Table 3 The diagram in FIG. 4 again illustrates the mean RCS value (Ds) for rubber balls with different wall thicknesses d as a function of the diameter D of the hollow balls. Furthermore, the corresponding RCS value of a metallic ball is plotted as a comparison value.
  • the curve LO in FIG. 4 shows the course of the RCS value for the metallic ball.
  • line L2 to a hollow sphere with a wall thickness of d 4 mm
  • line L3 to a hollow sphere with a wall thickness of d 6 mm
  • the largest RCS values are indeed achieved for a hollow sphere with a wall thickness of 6 mm. Nonetheless, the RCS values are also significantly greater for the other wall thicknesses than for a corresponding metallic sphere.
  • the minimum RCS values according to Table 2 above remain low even with large spheres.
  • the frequencies that correspond to the minimum points are determined by the diameter of the hollow sphere and the nature of the wall of the outer wall of the hollow sphere.
  • several hollow spheres with different diameters and / or wall thicknesses can be provided in the spatial area covered by the radar radiation.
  • the diameter and wall thickness of the hollow spheres can be coordinated in such a way that the minimum and maximum points of the frequency-dependent curves of the RCS values of the individual hollow spheres overlap in such a way that a balanced frequency curve of the radar cross-section resulting from all hollow spheres is achieved.
  • a person skilled in the art can determine suitable diameters and wall thicknesses based on appropriate analytical calculations.
  • Fig. 5 shows a modified embodiment of a hollow sphere which is used in a Vari ante of the method according to the invention for reflecting radar beams.
  • the beam courses shown in FIG. 5 of radar beams transmitted via the radar device 2 correspond to the beam courses in FIG. 2 and are therefore not explained again.
  • the only difference between Fig. 2 and Fig. 5 consists in that in the interior lb of the hollow ball 1, a further ball 3 is provided from metallic material.
  • the diameter of this ball 3 is selected such that the beam path of radar beams with two and also a larger number of reflections on the inside of the outer wall 1 a of the hollow ball 1 is not hindered by the metallic ball 3.
  • the inventor was also able to prove that the mean radar cross-section of the hollow sphere from FIG. 5 is only slightly influenced by the inner metallic sphere 3 as long as the beam path P for twice reflected rays inside the hollow sphere is not hindered. Approximately, the diameter of the inner metallic ball should not exceed 70% of the diameter D of the hollow ball 1.
  • an inflatable gas balloon is used as a hollow sphere for reflecting radar radiation, which gas balloon is filled with an electrically neutral gas which has a lower density than air, so that the balloon can be positioned in a freely floating position.
  • the balloon can be tied up by means of a leash or positioned freely floating without securing.
  • By changing the gas pressure of the balloon its backscattering properties can be changed in a simple manner.
  • a gas balloon that is a few meters in diameter usually has very high RCS values, even at low radar frequencies, such as in the X-band or other bands with even lower frequencies, as long as the diameter of the balloon is greater than approx. 30 wavelengths is the longest wavelength of the radar radiation.
  • Gas balloons can be used in combination with the detection of their radar cross-section via radar beams, for example as weather balloons to measure wind speeds at greater heights.
  • FIG. 6 and FIG. 7 show again in section modified embodiments which can be used in the context of the method according to the invention.
  • a group of three hollow spheres 1 with different diameters is arranged next to one another in the horizontal direction.
  • These hollow spheres are inflated gas balloons which are filled with gas with a lower density than the surrounding air and are held in position by means of appropriate lines 4 or possibly also rods.
  • the radar radiation emitted is indicated by concentric lines in the upper left part of FIG. 6.
  • the hollow spheres of FIG. 6 do not necessarily have to be implemented as gas balloons.
  • the balls can also be non-deformable.
  • the outer wall consists of a non-flexible material.
  • FIG. 7 shows a modification of the embodiment of FIG. 6. This modification differs from FIG. 6 only in that the hollow balls are not arranged horizontally next to one another, but vertically one above the other Poles connected to each other and to the ground. For both embodiments of FIGS. 6 and 7, care must be taken that the arrangement of the balls relative to one another is such that they do not cover one another and remain visible from the position of the radar device.
  • a sufficiently small interior space of a gas balloon can also be used as a “cargo space”.
  • the The size of the room can be up to about 70% of the balloon diameter. In this space, for example, cargo, people or another radar reflector (Winkelreflek gate) can be arranged.
  • the outer wall of the gas balloon not only serves as a radar reflector, but also as a protective radome.
  • a hollow sphere with a fixed spherical shell can also be used, with a usable space optionally also being provided in the middle of the hollow sphere in this case.
  • the hollow sphere can be mounted, for example, on a tip of a pointed carrier.
  • the hollow spheres described above can be used as radar reflectors for backscattering radar radiation in a variety of application areas.
  • an effective, fast and independent of the position of the radar device marking of objects and terrain can be achieved.
  • Corresponding hollow spheres can also serve as strong and individually recognizable radar targets, e.g. as decoy targets.
  • Safety and disaster control as a marker to identify objects (lifeboats and rafts, free-floating containers and the like) in the water, especially in darkness or fog, in these cases preferably hollow spheres in the form of tied, inflatable and high-floating gas balloons be used; for the navigation of rescue personnel, robots and autonomous vehicles, e.g. in dark, smoky rooms; Marking of dangerous areas (e.g. passages in snow, mountain and swamp areas or in mined terrain);
  • - Shipping Marking of the fairway, including coastal and port areas
  • - Road traffic Determining the position of vehicles on the road, eg by marking the edge of the road or marking construction sites using hollow spheres, preferably using fixed hollow spheres (autonomous driving, driving safety);
  • - Radar technology as a calibration body for the calibration of radars of different types (ground, air, space-based) in different frequency bands (e.g. from L to W band);
  • the inventive concept described in the foregoing of using partially transparent hollow spheres as radar reflectors has a number of advantages. Due to the spherical symmetry of the hollow sphere, the radar cross-section is completely independent of the direction of the radar radiation. In contrast to this, plate, angle and Lüneburg reflectors ensure that the radar cross-section is direction-independent only for certain spatial areas.
  • Hollow balls very high RCS values can be achieved, which are significantly higher than for metallic balls and most dielectric balls of the same size.
  • Hollow spheres also have a significantly lower weight than solid spheres. As a result, they can also have very large diameters, so that very high RCS values can be guaranteed.
  • the pronounced frequency dependence of the radar cross-section of partially transparent hollow spheres can be used as an individual feature for recognizing the hollow spheres.
  • individual radar reflectors can be identified by evaluating the frequency-dependent course of the radar cross-section and differentiated from other radar reflectors.
  • Partially transparent hollow spheres can be easily implemented and manufactured. Their radar cross-section can easily be simulated, as an exact solution for this radar cross-section is known.
  • desired frequency-dependent curves of radar cross-sections can be implemented by defining suitable materials and wall thicknesses for the outer wall of the hollow spheres and suitable spherical diameters via simulations.
  • Partly transparent hollow spheres can easily be installed without any special position requirements due to the fact that their radar cross-section is independent of direction.
  • the hollow spheres can be easily adapted to the frequency range of the radar radiation used.

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  • Radar Systems Or Details Thereof (AREA)

Abstract

L'invention porte sur un procédé destiné à détecter une zone spatiale au moyen d'ondes radar. Selon le procédé, un appareil radar (2) émet des ondes radar dans la zone spatiale et reçoit des échos radar (RE) de la zone spatiale, les échos radar résultant de la rétrodiffusion des ondes radar par la zone spatiale. L'appareil radar (2) traite les échos radar (RE) reçus afin de déterminer des informations concernant la zone spatiale. Dans la zone spatiale, une ou plusieurs sphères (1) sont installées en tant que réflecteurs radar, chaque sphère comprenant une paroi extérieure sphérique (1a), laquelle est partiellement transparente et partiellement réfléchissante pour les ondes radar de l'appareil radar (2). À l'intérieur de chaque sphère (1), une zone creuse (1b) joint la paroi extérieure (1a), ladite zone creuse étant dimensionnée de sorte que des faisceaux radar (P, P') de rayonnement radar (RS, RS') de l'appareil radar (2), ledit rayonnement radar entrant par le biais de la paroi extérieure (1a), se produisent à l'intérieur de la sphère (1), lesdits faisceaux radar étant réfléchis deux fois et trois fois, respectivement, sur la paroi extérieure (1a) et sortant ensuite par le biais de la paroi extérieure (1a) en tant qu'écho radar (RE, RE') en face de et parallèlement à la direction d'incidence du rayonnement radar entrant (RS, RS'), l'appareil radar (2) détectant la sphère (1) au moyen de l'écho radar (RE, RE').
PCT/EP2020/085711 2019-12-18 2020-12-11 Procédé et dispositif destinés à détecter une zone spatiale au moyen d'ondes radar WO2021122361A1 (fr)

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DE102019219970.4A DE102019219970A1 (de) 2019-12-18 2019-12-18 Verfahren und Vorrichtung zur Erfassung eines Raumbereichs mittels Radarwellen
DE102019219970.4 2019-12-18

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