Noise filter for radar measurement systems, radar measurement system, and firing mechanism having a radar measurement system

Abstract

The invention relates to a passive noise filter (1) for radar measurement systems for increasing the signal-to-noise ratio. The noise filter (1) comprises a rotationally symmetrical hollow element (2), the hollow element wall (2.1) of which is made of a base material that is permeable to radio waves, wherein rod-like shielding inserts (3) consisting of a shielding material that is impermeable to radio waves are embedded in the hollow element wall (2.1). The radar measurement system equipped with the noise filter (1) is suitable in particular as an add-on unit for firing mechanisms (6) for the purpose of monitoring the trajectory of bullets and projectiles.

Description

[0001] Noise filter for radar measuring systems, radar measuring system and launcher with radar measuring system

[0002] The invention relates to a noise filter for increasing the signal-to-noise ratio for radar measurement systems operating using electromagnetic radio waves. Furthermore, the invention relates to a radar measurement system with such a noise filter and a launch device with the radar measurement system. The noise filter serves to improve the reception sensitivity of radar measurement systems when receiving electromagnetic radio waves, particularly in the wavelength range from 100 MHz to approximately 500 GHz.

[0003] Measurement and detection methods using electromagnetic waves have the advantage that, by appropriately determining the wavelength of the electromagnetic waves used, the objects to be detected or examined can be visualized under a wide variety of conditions. For example, if visibility is obstructed by vapors in the visible wavelength range, switching to low-frequency waves allows penetration of the vapors.

[0004] The detection of (metallic) objects using radar waves, i.e., electromagnetic waves in the radio range, is well known – in both civilian and military applications. These radar measurement systems emit radio waves that are diffusely reflected, i.e., distributed in all directions, by (moving) objects. They then detect the radio waves reflected by the objects. This allows the existence, distance, direction, and speed of the objects to be detected or verified. Due to the constant speed and rectilinear propagation of the electromagnetic waves, the distance and speed of such objects can be measured precisely. By selecting the radio wavelength, adaptation to the geometric dimensions of the object to be measured is also possible.

[0005] DE 23 12 065 A describes a waveguide mode filter which, in order to support the propagation of circular electrical wave modes in a hollow cylinder, provides for the attachment of several longitudinally arranged resistance strips to the inner surface of the waveguide lining to absorb the energy of unwanted modes.

[0006] The accuracy of the distance measurement, and thus of the recorded speed, depends largely on the signal-to-noise ratio. The less the received echo signal is obscured by interference (noise), the more accurate the measurement.

[0007] For small objects, such as rifle projectiles, the effective backscattering area is small. Furthermore, the transmitted power arriving at the object being measured is reflected in all directions. Typically, only a small portion of this reflected power is received by the radar measurement system.

[0008] In addition, the resolution of the captured image is limited - not least due to the significantly longer wavelength of radio waves compared to light waves - so that details of the objects detected by radio waves are hardly or not at all visible, especially at larger measuring distances.

[0009] The power of the emitted radio waves also influences the signal-to-noise ratio and thus the maximum possible resolution. The trend toward ever-miniaturizing radio wave emitters in radar measurement systems inevitably leads to reduced emission power and thus to a deteriorated resolution or a reduced signal-to-noise ratio.

[0010] Preferably, the smoke suppression or filtering to improve the signal-to-noise ratio is carried out passively, i.e. without additional power supply or complex control components. From DE 10 2019 108 741 A1, a noise suppression device for electromagnetic measuring systems to improve the signal-to-noise ratio in the form of a hollow cylinder made of metallic foam that can be attached to a radio wave emitter is known. The invention is based on the object of avoiding the above-mentioned disadvantages, such as poor resolution of the images of objects detected by means of long-wave electromagnetic waves, in particular when using radio wave emitters with low transmission power, whereby an improved noise filter for radar measuring systems is to be provided, which enables radar measuring systems based on electromagnetic

[0011] Radio waves - particularly in the wavelength range from 100 MHz to 500 GHz - are to be realized, whereby the noise filter should enable an increase in the signal-to-noise ratio and the spatial resolution in a measurement without the need for electronic components.

[0012] This object is achieved by a noise filter having the features of claim 1 and a radar measurement system having the features of claim 8; expedient embodiments of the invention are found in the subclaims. An advantageous integration of the radar measurement system into a launching device is described in claim 10.

[0013] According to the invention, a noise filter is provided for a radar measuring system that emits electromagnetic radio waves and detects the reflected signal thereof. The noise filter comprises a hollow body that is rotationally symmetrical to a hollow body axis and extends along the hollow body axis over an entire axial length. The hollow body of the noise filter has an axially continuous cavity that extends along the hollow body axis and is encased by a hollow body wall.

[0014] Rotational symmetry is understood here to mean that bodies or arrangements (here, for example, the hollow body) are imaged onto themselves when rotated by certain angles around an axis (here the hollow body axis). Self-image upon rotation of 120° is referred to, for example, as threefold rotational symmetry, and self-image upon rotation of 60° is referred to as sixfold rotational symmetry. The special form of rotational symmetry, in which self-image occurs upon rotation by any angle, is referred to here as rotational symmetry for the purpose of differentiation. The hollow body preferably has the shape of a straight hollow cylinder open on both sides, whereby the term hollow cylinder is understood to mean any shaped body that has a centrally arranged through-opening. The base area of ​​the hollow cylinder can have any shape, but is preferably rectangular or oval (including circular).

[0015] Likewise, the cross-sectional area of ​​the cavity enclosed by the hollow body wall can have any shape, whereby the shape of the cavity cross-sectional area can be variable along the hollow body axis, but usually remains the same.

[0016] In its hollow cylinder design, the hollow body preferably has a cross-sectional geometry that is constant along the hollow body axis with respect to the hollow body wall and the hollow space. However, it can also have the geometric shape of a hollow cone or truncated pyramid, for example.

[0017] The noise filter also features several straight, rod-shaped shielding inserts extending over the entire length of the hollow body and embedded in the hollow body wall. Each of the shielding inserts runs or lies in an axial plane of the hollow body containing the hollow body axis. The hollow body wall has insert openings or recesses corresponding to the shape of the shielding inserts, into which the shielding inserts are inserted. If the shielding inserts are designed as round rods, for example, the insert openings are correspondingly adapted bores. Typically, the rod-shaped shielding inserts have a consistent cross-sectional geometry across their entire extension or rod length.

[0018] According to the invention, the shielding elements are arranged in the hollow body wall with at least threefold rotational symmetry relative to the hollow body axis. The arrangement of the shielding elements preferably has four-, five-, or higher-fold rotational symmetry relative to the hollow body axis, in particular six- or eight-fold rotational symmetry. According to the invention, the hollow body wall of the hollow body is constructed from a base material permeable to electromagnetic radio waves; the shielding elements, in contrast, are each formed from a shielding material impermeable to electromagnetic radio waves. The base material is preferably a compact material or a solid material.

[0019] The radar measuring system according to the invention comprises - in a basically known manner - a radio wave emitter for emitting the radio waves and a radio wave receiver for receiving the (reflected) radio waves.

[0020] The radio wave emitter and the radio wave receiver can, for example, be integrated into a radar measurement system chip. The noise filter is attached to the radar measurement system chip, as described, for example, in DE 10 2019 108 741 A1, i.e., installed as a top or front attachment in front of the radio wave receiver. The noise filter with the described features is thus arranged in front of the radio wave emitter (also radar wave emitter) or radio wave receiver (also radar wave receiver) of the radar measurement system in such a way that the emitted or detected radio waves travel through the cavity from the radio wave emitter or to the radio wave receiver. The hollow body axis is preferably aligned parallel to the electromagnetic radio waves emitted by the radio wave emitter of the radar measurement system.

[0021] The wavelength of the radio waves emitted by the radio wave emitter is preferably in the wavelength range of 100 MHz to 500 GHz.

[0022] The radio wave emitter of the radar measuring system is preferably designed to emit electromagnetic radio waves at a predetermined radio wavelength. The arrangement of the shielding elements is suitably matched to this predetermined radio wavelength. For this purpose, the shielding elements in the hollow body of the noise filter are arranged, for example, such that, in each radial plane of the hollow body perpendicular to the hollow body axis, each of the shielding elements is spaced from its adjacent shielding element by a distance in the range of 50% ± 10% of the predetermined radio wavelength. In particular, the radar measuring system can comprise a radar measuring system chip in the form of a semiconductor chip or be designed as such a semiconductor chip, wherein the area of ​​the semiconductor chip preferably does not exceed 100 square centimeters.

[0023] It has been shown that the noise filter constructed as a perforated, symmetrical hollow body, when placed in front of the radio wave emitter or radio wave receiver of the radar measuring system, can significantly improve the signal-to-noise ratio and improve the resolution of the image acquired by the radar measuring system by orders of magnitude.

[0024] The symmetrical arrangement of the rod-shaped shielding elements placed around the cavity acts as a cage-like, lateral enclosure for the radio wave emitter or radio wave receiver. This attenuates the noise caused by stray waves incident from the side. The inventive alignment of the rod-shaped shielding elements allows radio waves aligned along the cavity axis—that is, the radio waves that are the primary signal carriers—to pass preferentially to the radio wave receiver.

[0025] The advantages of the noise filter according to the invention when used as intended in a radar measuring system include the simple, compact design, the feasibility of small component sizes and the elimination of error-prone, power-consuming electronic components.

[0026] The radar measuring system according to the invention can be used, among other things, for joining workpieces or for repairing steel structures by welding. The radar measuring system allows the detection of edges of the workpieces or the gap to be welded, the determination of the size and / or position of the gap, and the detection of the positioning and alignment of the workpieces to be joined in space or relative to one another. Since fumes often develop during welding, the radar measuring system enables reliable detection of the aforementioned parameters through the fumes. It can also be used for underwater welding when visibility is obstructed by murky water or steam formation. Another useful application of the radar measuring system is the trajectory monitoring of projectiles or missiles, whereby parameters such as the distance, direction, and speed of the projectiles or missiles can be detected using the radar measuring system.

[0027] According to the invention, a launching device is provided which has a barrel for launching projectiles or missiles and which comprises the described radar measuring system, wherein the hollow body axis of the hollow body of the noise filter is preferably aligned parallel to the barrel of the launching device. The radar measuring system can be attached, for example, to the stock or to the aiming optics of a launching device designed as a rifle. It is also possible to install the radar measuring system with a hollow body of the noise filter arranged coaxially at the muzzle of the barrel. By integrating the radar measuring system into the launching device for projectiles or missiles, the improved parameter recording can

[0028] Accuracy can be increased—for example, through readjustment. The collected information is particularly useful in the field of sport shooting to optimize shooting performance during shooting training.

[0029] According to a preferred embodiment of the noise filter, the base material of the hollow body wall is a non-metallic material, for example a plastic or a ceramic material.

[0030] The shielding material from which the shielding elements are formed is preferably a metallic material, for example an aluminum, a copper or an iron material.

[0031] The shielding elements can, for example, consist of a wire-shaped shielding material, i.e. the shielding elements are designed as wires made of compact material.

[0032] Alternatively, the shielding material can be a powdered material that is introduced into the insert openings or recesses in the hollow body wall and fixed therein. Similarly, the shielding material can be a powder-based material, for example, a sintered material. Powdered and powder-based materials offer improved filtering efficiency due to their larger internal surface area.

[0033] Furthermore, it can be provided that the shielding elements, either as a whole or within each of several subsets, each have the same cross-sectional geometry in a radial plane of the hollow body perpendicular to the hollow body axis. On the one hand, all shielding elements, i.e. the entirety of the shielding elements, can have the same cross-sectional geometry. On the other hand, or alternatively, the shielding elements can be divided into subsets, whereby only within the subset does the same cross-sectional geometry exist in a radial plane of the hollow body perpendicular to the hollow body axis; the cross-sectional geometry of the shielding elements from different subsets, however, can differ. In this way, it is possible, for example, to realize certain particularly filter-effective symmetrical arrangement patterns of the shielding elements in the hollow body wall.

[0034] According to the above-described configuration, the shielding elements with the same cross-sectional geometry can also be arranged at equal spacing from one another in each radial plane of the hollow body perpendicular to the hollow body axis on a circle concentric to the hollow body axis. This generally results in a rotationally symmetrical rod cage, in the simplest case with the rod-shaped shielding elements arranged coaxially with the hollow body axis.

[0035] The invention is explained in more detail below using exemplary embodiments and with reference to the schematic drawings, wherein identical or similar features are provided with the same reference numerals; in this case:

[0036] Fig. 1: a first embodiment of the noise filter in perspective view, Fig. 2: a second embodiment of the noise filter in perspective view, Fig. 3: a third embodiment of the noise filter in perspective view, Fig. 4: the radar measuring system with a fourth embodiment of the noise filter in perspective view,

[0037] Fig. 5: a hunting rifle with possible installation positions of the radar measuring system in the longitudinal profile, and

[0038] Fig. 6: A sports shooter training with a small-caliber rifle incorporating the radar measuring system in perspective view.

[0039] The noise filter 1 according to Fig. 1 has a hollow body 2 designed as a straight hollow circular cylinder open on both sides, with the hollow body wall 2.1 made of plastic enclosing the inner cavity 2.2. Eight circular cylindrical, rod-shaped, metallic shielding inserts 3 are embedded in the hollow body wall 2.1. Each of the shielding inserts 3 runs longitudinally in an axial plane 4.1 of the hollow body 2 containing the hollow body axis 4. The rod-shaped shielding inserts 3 according to the first embodiment of the noise filter 1 according to Fig. 1 are aligned parallel to the hollow body axis 4. Furthermore, the shielding inserts 3, which all have the same cross-sectional geometry, are arranged at equal distances from one another in each radial plane 4.2 lying perpendicular to the hollow body axis 4 on a circle lying concentric to the hollow body axis 4. This arrangement of the shielding inserts 3 according to Fig.1 thus has an eightfold rotational symmetry with respect to the hollow body axis 4. To illustrate the position and orientation of the axial planes 4.1 and the radial planes 4.2 of the hollow body 2, an axial plane 4.1 and a radial plane 4.2 of the hollow body 2 are shown as examples in Fig. 1; the shielding inserts 3 are partially shown with hidden edges for clarity.

[0040] The second embodiment of the noise filter 1 according to Fig. 2 also has a hollow body 2 designed as a straight hollow circular cylinder open on both sides. It comprises 18 rod-shaped shielding inserts 3, which consist of two subsets, each with a different cross-sectional geometry. The shielding inserts 3 are arranged parallel to the hollow body axis 4 in a six-fold rotational symmetry with respect to the hollow body axis 4. The shielding inserts 3 with a larger cross-section are arranged at equal distances from one another in each of the radial planes 4.2 perpendicular to the hollow body axis 4 on a circle concentric to the hollow body axis 4. Between each shielding insert 3 with a larger cross-section, two shielding inserts 3 with a smaller cross-section are arranged, whereby these two shielding inserts 3 with a smaller cross-section, each located between two adjacent shielding inserts 3 with a larger cross-section, run in an axial plane 4.1. In the radial planes 4.2, the shielding inserts 3 with smaller cross-sections are located on two concentric circles.

[0041] The third embodiment of the noise filter 1 according to Fig. 3 corresponds to the first embodiment according to Fig. 1 with regard to the shielding inserts 3 and their arrangement, but in contrast to the first embodiment has a hollow body 2 with a cuboid-shaped outer contour and a circular-cylindrical cavity 2.2.

[0042] The noise filter 1 according to the fourth embodiment shown in Fig. 4 has a hollow body 2 formed as a straight hollow truncated cone open on both sides. The rod-shaped shielding inserts 3 are each arranged in an axial plane 4.1 of the hollow body 2 containing the hollow body axis 4; they follow the surface lines of the hollow truncated cone, running approximately in the center of the wall thickness in the hollow body wall 2.1.

[0043] Furthermore, Fig. 4 shows the noise filter 1 according to the fourth embodiment as part of the radar measuring system according to the invention: The noise filter 1 with the conically shaped hollow body 2 is mounted on the radar measuring system chip 5, which contains the radio wave emitter and the radio wave receiver, in such a way that the radio waves emitted by the radio wave emitter run parallel to the hollow body axis 4 through the cavity 2.2 of the hollow body 2.

[0044] Fig. 5 shows, based on the design of the launching device 6 in the form of a hunting rifle, two possible positions for attaching the radar measuring system, namely, on the one hand, a position in the muzzle area of ​​the barrel 6.1 and, on the other hand, a position on the aiming optics of the hunting rifle.

[0045] Another mounting position of the radar measuring system is illustrated in Fig. 6, in which a sports shooter is depicted with a launching device 6 in the form of a small-caliber rifle during shooting practice. The radar measuring system is attached to the fore-end of the small-caliber rifle. Using the radar measuring system, it is possible to measure the parameters of the target measured by the

[0046] The aim is to measure the projectile fired from a small-caliber rifle. Based on precise knowledge of the projectile parameters, athletes' shooting performance can be specifically optimized.

[0047] List of reference symbols

[0048] 1 noise filter

[0049] 2 Hollow body 2.1 Hollow body wall

[0050] 2.2 Cavity

[0051] 3 Shielding insert

[0052] 4 hollow body axis

[0053] 4.1 Axial plane of the hollow body 4.2 Radial plane of the hollow body

[0054] 5 radar measurement system chip

[0055] 6 Launching device

[0056] 6.1 Run

Claims

AMENDED CLAIMS received by the International Bureau on 25 March 2025 1. A noise filter (1) of a radar measuring system operating by means of electromagnetic radio waves, said noise filter comprising a hollow body (2) which is rotationally symmetrical to a hollow body axis (4) of the hollow body (2) and extends along the hollow body axis (4) over an entire axial length, wherein the hollow body (2) comprises an axially continuous cavity (2.2) which extends along the hollow body axis (4) and is surrounded by a hollow body wall (2.1), and wherein the hollow body wall (2.1) is constructed from a base material which is permeable to electromagnetic radio waves, characterized in that the noise filter (1) comprises a plurality of noise filters which extend over the entire length of the hollow body (2) and are embedded in the hollow body wall (2.1).1 ) has embedded, each straight, rod-shaped shielding inserts (3), which are each formed from a shielding material impermeable to electromagnetic radio waves, wherein each of the shielding inserts (3) runs in an axial plane (4.1 ) of the hollow body (2) containing the hollow body axis (4), and wherein the shielding elements (3) are arranged in the hollow body wall (2.1 ) with at least threefold rotational symmetry to the hollow body axis (4).

2. Noise filter (1) according to claim 1, characterized in that the base material of the hollow body wall (2.1) is a non-metallic material.

3. Noise filter (1) according to claim 1 or 2, characterized in that the shielding material from which the shielding elements (3) are formed is a metallic material.

4. Noise filter (1) according to one of claims 1 to 3, characterized in that the shielding elements (3) are formed from a wire-shaped, a powder-shaped or a powder-based shielding material.

5. Noise filter (1) according to one of claims 1 to 4, characterized in that the hollow body (2) is a straight hollow cylinder. AMENDED SHEET (ARTICLE 19) 6. Noise filter (1) according to one of claims 1 to 5, characterized in that the shielding elements (3) within their entirety or within each of several subsets in a radial plane (4.2) of the hollow body (2) lying perpendicular to the hollow body axis (4) each have the same cross-sectional geometry.

7. Noise filter (1) according to claim 6, characterized in that the shielding elements (3) with the same cross-sectional geometry are arranged at equal distances from one another in each radial plane (4.2) of the hollow body (2) lying perpendicular to the hollow body axis (4) on a circle lying concentrically to the hollow body axis (4).

8. Radar measuring system, characterized in that it comprises a noise filter (1) according to one of claims 1 to 7, wherein the hollow body axis (4) is aligned parallel to the electromagnetic radio waves emitted by a radio wave emitter of the radar measuring system.

9. Radar measuring system according to claim 8, characterized in that the radio wave emitter of the radar measuring system is designed to emit electromagnetic radio waves with a predetermined radio wavelength (A), wherein the shielding elements (3) in the hollow body (2) of the noise filter (1) are arranged such that in each radial plane (4.2) of the hollow body (2) lying perpendicular to the hollow body axis (4), each of the shielding elements (3) has a distance from its respectively adjacent shielding element (3) which is in the range of 40% to 60% of the radio wavelength.

10. Launching device (6) comprising a barrel (6.1) for launching projectiles or missiles, characterized in that the launching device (6) comprises a radar measuring system according to claim 8 or 9, wherein the hollow body axis (4) is aligned parallel to the barrel (6.1) of the launching device (6). AMENDED SHEET (ARTICLE 19) Declaration under Article 19 (1) PCT Claim 1 was specified in such a way that the noise filter is part of a radar measuring system operating by means of electromagnetic radio waves. The amendment is based on the originally submitted version of the invention description, page 6, lines 20-23.

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