Zenith Reactive Jammer

Abstract

The present invention relates to a jamming device (1) for protecting targets on the Earth's surface from space, satellite, or aircraft-type radio frequency (RF) threats. The jamming device (1) comprises RF threat detection means (11), RF jamming means (12), and a control system (13). The RF threat detection means (11) comprises a plurality of receiving antennas (111), an RF threat detection unit (112), and one or more predetermined RF threat-related libraries (113). The receiving antennas (111) are configured to receive RF signals having an arrival elevation angle equal to or greater than a given minimum elevation angle, thereby achieving an elevation angle coverage range of interest. The RF threat detection unit (112) is configured to detect the presence of RF threats based on the RF signals received by the receiving antenna (111) and a predetermined RF threat association library (113), and, if an RF threat is detected, determine the type of each detected RF threat based on the RF signals received by the receiving antenna (111) and the predetermined RF threat association library (113), estimate the direction of arrival of each detected RF threat based on the RF signals received by the receiving antenna (111), and alert the control system (13) about the detected RF threats by providing the type and direction of arrival of each detected RF threat to the control system (13). The predetermined RF threat association library (113) includes information related to the RF threats of interest such that the RF threat detection unit (112) can detect the presence of one or more RF threats of interest and determine the type of each RF threat based on the RF signals received by the receiving antenna (111). The control system (13) comprises a control unit (131) and one or more predefined RF jamming action related libraries (132).The control unit (131) is configured to, when the RF threat detection unit (112) detects an RF threat, determine an RF jamming action to be taken against the detected RF threat based on the type determined by the RF threat detection unit (112) and a predetermined RF jamming action association library (132), and operate the RF jamming means (12) to perform the determined RF jamming action against the detected RF threat. The predetermined RF jamming action association library (132) includes, for each RF threat of interest inserted into the predetermined RF threat association library (113), respective information on one or more respective RF jamming actions to be taken against the RF threat of interest. The RF jamming means (12) is operable by a control unit (131) when an RF threat is detected by the RF threat detection unit (112), and comprises a plurality of transmit / receive antennas (121) configured to transmit RF jamming signals to the detected RF threat to further realize the elevation angle coverage range of interest, track the detected RF threat, and implement an RF jamming action determined by the control unit (131), and an RF jamming signal generating unit (122) configured to generate an RF jamming signal to be transmitted by the transmit / receive antennas (121) to the detected RF threat to implement the RF jamming action.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to European Patent Application No. 20425047.6, filed November 5, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates generally to the field of electronic countermeasures (ECM).

[0003] More particularly, the present invention relates to a zenith reactive jammer, i.e., a reactive jamming device for providing protection against radio frequency (RF) remote sensing sensors or systems operating at high elevation angles (e.g., radar-based sensors / systems (e.g., imaging radars) or synthetic aperture radars (SARs) mounted on space or airborne platforms such as satellites, aircraft, drones, etc.). [Background technology]

[0004] As is known, the purpose of jamming systems for defending against radar or SAR sensors / systems is to protect an area, site (e.g., of either civilian or military type), or asset of interest by disrupting the enemy's sensor's ability to recognize and / or extract relevant information.

[0005] In the case of SAR sensors in particular, the objective is to degrade the image quality as much as possible in order to defocus or otherwise obscure the area of ​​interest and thus provide adequate protection in either maritime or land-based scenarios.

[0006] For example, U.S. Patent No. 10,852,391 B2 relates to a method and related device for jamming synthetic aperture radar. Specifically, U.S. Patent No. 10,852,391 B2 describes a method for jamming airborne SAR-type radar, which is implemented by a radar jamming device comprising a group of at least two cooperating units surrounding an area on the ground to be protected, wherein: at least two units of the group have radar detection capabilities; At least one unit of this group is equipped with radar jamming capabilities; each unit having radar detection capability comprises a receiving and processing module configured to analyze received signals; each unit having radar jamming capability configured to generate and transmit a jamming signal; · Each unit is linked to another by at least one two-way data link and synchronized by a common clock.

[0007] More specifically, the method according to U.S. Pat. No. 10,852,391 B2 comprises: - Identify whether the received signal corresponds to a SAR signal, characterizing the received SAR signal for a predetermined period of time that is shorter than the recurrence of the SAR signal; Calculating a filter adapted to the pulses of the received SAR signal; utilizing said adapted filter to perform pulse compression of the received SAR signal at each recurrence, thus obtaining a Doppler history linked to the movement of the platform carrying the radar; periodically and repeatedly characterizing the received signal over a predetermined period longer than the recurrence of the SAR signal in order to establish, from one recurrence to the next, the displacement velocity of the radar and the distance between said radar and the area to be protected; Calculates jamming signals to be transmitted at each point in the area to be protected in order to jam SAR radar coherently in the range and Doppler axes; Transmits a calculated jamming signal This includes:

[0008] In this situation, given the particularities of SAR technology (regarding the physical characteristics of both the SAR sensor and the SAR processing and imaging process) and the particularities of the airborne or space / satellite platforms typically used for the purpose of installing and transporting such sensors (regarding their kinematic characteristics), the effective success of jamming actions is unfortunately not guaranteed.

[0009] Furthermore, the high resolution imaging radar sensors that are increasingly being used today also exhibit similar inherent limitations in processing effectiveness versus jamming effectiveness.

[0010] Additionally, the aforementioned platform kinematic profile, which is particularly challenging for conventional electronic defense systems, is a further limiting factor.

[0011] Essentially, known types of jamming systems do not have the architectural flexibility and reactivity required to ensure simultaneous response to all the multiple aspects that need to be taken into account when implementing countermeasures against the aforementioned types of threats.

[0012] Indeed, to ensure the effectiveness of electronic defenses in such situations, several factors must be addressed.

[0013] Specifically, the technical difficulties are related to several aspects, such as: Long range (especially when compared to satellite sensors), The elevation angle of interest (either satellite or aircraft) for such threats, and Receiver processing Includes:

[0014] Regarding the first aspect, this requires high sensitivity of the receivers used in terms of threat detection capabilities.

[0015] In this case, the need for countermeasures to be timed to coincide with the ongoing threat development must be taken into account. This is true in principle for any type of platform with a rapidly evolving kinematic profile and therefore very short alarm and engagement times to counter.

[0016] Furthermore, in naval / sea or land scenarios, whether it is a matter of point defense (e.g., defense of a single naval platform, concealment of a single base, site and / or ground escort, etc.) or defense of a larger area (e.g., concealment of a fleet, defense of a series of bases, site and / or ground escort, etc.), the elevation angles involved are not typical for commonly available electronic defense systems, and such electronic defense systems do not have the flexibility to provide effective defense against such threats.

[0017] Another very challenging aspect is the high power required for the jamming system to be effective. Indeed, the latest generation of high-resolution imaging radars have a high processing gain in the coherent integration of signals reflected from the soil / target during the illumination time of the surveillance area. Therefore, the jamming system must be able to compensate for this gain in order to be effective. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] U.S. Patent No. 10,852,391B2 Summary of the Invention [Problem to be solved by the invention]

[0019] In view of the above, it is an object of the present invention to provide an innovative jamming device for protection against remote sensing sensors or systems (e.g., satellite / aircraft radar or SAR) operating at radio frequencies (RF) and at high elevation angles, which can at least partially overcome or mitigate the drawbacks and limitations of currently known jamming techniques. [Means for solving the problem]

[0020] This and other objects are thus achieved by the present invention, which relates to a jamming device according to what is defined in the appended claims.

[0021] In particular, the present invention relates to a jamming device for protecting targets on the Earth's surface from radio frequency (RF) threats of space, satellite or aircraft type, The jamming device RF threat detection methods, RF jamming measures, and Control System Equipped with The RF threat detection means Multiple receiving antennas, RF threat detection units, and One or more pre-defined RF threat-related libraries Equipped with the receive antenna is configured to receive RF signals having an elevation angle of arrival that is greater than or equal to a minimum elevation angle, thereby achieving an elevation angle coverage range of interest; The RF threat detection unit Detecting the presence of an RF threat based on the RF signal received by the receiving antenna and a predetermined RF threat related library; When detecting RF threats, - determining a type of each detected RF threat based on the RF signals received by the receiving antenna and a predetermined RF threat association library; - estimating a direction of arrival of each detected RF threat based on the RF signals received by the receiving antenna; - alerting a control system about detected RF threats, thereby providing the control system with each type and each direction of arrival of the detected RF threats; It is configured as follows: the predetermined RF threat-related library includes information related to one or more RF threats of interest such that the RF threat detection unit can detect the presence of the RF threats of interest and determine the type of each of the RF threats based on the RF signals received by the receiving antenna; The control system is - a control unit, and - One or more predefined RF jamming action related libraries Equipped with When the RF threat detection unit detects an RF threat, the control unit: - determining an RF jamming action to be performed on the detected RF threat based on each type determined by the RF threat detection unit and a predetermined RF jamming action association library; - operating an RF jamming device such that the RF jamming device performs the determined RF jamming action in response to the detected RF threat; the predetermined RF jamming action-related library includes, for each RF threat of interest inserted into the predetermined RF threat-related library, respective information regarding one or more respective RF jamming actions to be performed against the RF threat of interest; the RF jamming means is operable by the control unit upon detecting an RF threat by the RF threat detection unit; A plurality of transmitting and receiving antennas, - further realizing the elevation angle coverage range of interest; - Track detected RF threats, transmitting an RF jamming signal to the detected RF threat to perform an RF jamming action determined by the control unit. A plurality of transmitting and receiving antennas configured as described above; an RF jamming signal generating unit configured to generate an RF jamming signal to be transmitted by a transmitting / receiving antenna to a detected RF threat in order to perform the RF jamming action; Equipped with.

[0022] To facilitate a better understanding of the present invention, certain preferred embodiments will now be described with reference to the accompanying drawings (not to scale), which are presented for illustrative purposes only and are in no way limiting, let alone restrictive, examples. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram of a jamming device according to a preferred embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram of an RF threat detection means of the jamming device of FIG. 1; [Figure 3] 3 is a schematic diagram of an example of pointing of the receiving antenna of the RF threat detection means of FIG. 2 for detecting satellite SAR signals. [Figure 4] 2 is a schematic diagram of one embodiment of the receiving antenna for detecting satellite SAR signals. [Figure 5] FIG. 2 is a schematic diagram of a control system for the jamming device of FIG. 1; [Figure 6] FIG. 2 is a schematic diagram of an RF jamming means of the jamming device of FIG. 1; [Figure 7] 2 illustrates an embodiment of the jamming device of FIG. 1 for use on a naval platform to detect and nullify satellite SAR signals. [Figure 8] FIG. 1 is a diagram showing an example of a satellite SAR image. [Figure 9] 3A and 3B show an example of a corresponding SAR image acquired in the presence of jamming waves implemented by a jamming device according to the present invention in a satellite SAR countermeasure configuration. DETAILED DESCRIPTION OF THE INVENTION

[0024] The following description is provided to enable those skilled in the art to understand, make, and use the present invention. Various modifications to the presented embodiments will be readily apparent to those skilled in the art. Furthermore, the general principles disclosed herein may be applied to other embodiments and applications without departing from the scope of protection of the present invention as defined in the appended claims.

[0025] Therefore, the present invention should not be understood as being limited solely to the described and illustrated embodiments, but should be accorded the widest scope of protection in accordance with the features defined in the appended claims.

[0026] The present invention relates to a jamming device for protecting targets on the Earth's surface, whether mobile or stationary, such as terrestrial or naval platforms (e.g. land vehicles, naval units, etc.) or areas or sites of interest, from radio frequency (RF) threats of the space, satellite or aircraft type, such as radar or SAR sensors or systems or RF remote sensing sensors or systems.

[0027] To facilitate a better understanding of the present invention, FIG. 1 shows a block diagram that schematically illustrates the high-level functional architecture of a jamming device (generally designated 1) according to a preferred embodiment of the present invention.

[0028] Specifically, the jamming device 1 (hereafter simply referred to as the jammer for simplicity) RF threat detection means 11, RF jamming measures12, and Control System 13 Equipped with.

[0029] In this regard, it is important to note that the jammer 1 preferably consists of a single apparatus / device incorporating said RF threat detection means 11, said RF jamming means 12 and said control system 13.

[0030] Furthermore, as shown in Figure 1, the jammer 1 is preferably connected in wired or wireless mode to a user interface means 2 located outside said jammer 1 (e.g. a computer, laptop, station etc. dedicated to the control of the jammer 1 by a user or operator).

[0031] The RF threat detection means 11 represents a passive part of the jammer 1 dedicated to monitoring a given angle sector (in azimuth and elevation) to detect the presence of an RF threat (e.g., a satellite / aircraft SAR sensor / system, a satellite / aircraft radar sensor / system, or a satellite / aircraft RF remote sensing sensor / system, etc.) transmitting a microwave signal or more generally an RF signal that irradiates the target to be protected (e.g., an area or site of interest, or a terrestrial or naval platform, etc.) where the jammer 1 is installed.

[0032] In contrast, RF jamming means 12 represents the active part of jammer 1 dedicated to delivering RF jamming means, for example to impair / prevent extraction of relevant information (e.g., location, distance, shape, etc.) about the target to be protected.

[0033] Finally, the control system 13 · Managing RF threat detection measures 11 for monitoring areas of interest; Activation and proper operation of RF jamming means 12 upon receiving an alarm from RF threat detection means 11; results.

[0034] In this regard, it makes no sense that incorporating the RF threat detection means 11, the RF jamming means 12 and the control system 13 into a single apparatus / device (i.e., jammer 1) contributes to reducing the latency in delivery of the jamming means.

[0035] 2 is a block diagram showing a high-level functional architecture of the RF threat detection means 11. The high-level functional architecture of the RF threat detection means 11 includes: a plurality of receiving antennas 111; an RF threat detection unit 112; and One or more pre-defined RF threat-related libraries 113 The predetermined RF threat related library 113 may conveniently be stored in an internal memory of the RF threat detector unit 112 or in an external memory of the RF threat detector unit 112.

[0036] More specifically, the receive antenna 111 is configured to receive RF signals having elevation angles of arrival, where these elevation angles of arrival are: greater than or equal to a given minimum elevation angle (advantageously greater than or equal to 20°, preferably comprised between 20° and 65°), or preferably within a given elevation angle range defined by this given minimum elevation angle and by a given maximum elevation angle above said given minimum elevation angle (e.g., an elevation angle of arrival within the range of 20°-40° or within the range of 20°-45° for avionics RF threats, or an elevation angle of arrival within the range of 30°-60°, 30°-65°, or 30°-70° for satellite RF threats, or an elevation angle of arrival within the range of 60°-90° or within the range of 65°-90° for zenith or quasi-zenith RF threats, etc.).

[0037] Therefore, the receiving antenna 111 (and therefore the RF threat detection means 11) enables an elevation angle coverage range associated with RF signals having a high arrival elevation angle relative to the jammer 1 (more precisely, relative to a given horizontal reference plane of the jammer 1), and further, the elevation angle coverage range may conveniently be zenithal or quasi-zenithal.

[0038] Preferably, the receiving antenna 111 is configured to receive RF signals having the elevation angle of arrival and the azimuth angle of arrival within the range of 0° to 180° or within the range of 0° to 360°, thereby enabling, in addition to the elevation angle coverage range, an azimuth angle coverage range of 180° or 360° centered on the zenith direction of the jammer 1 (the zenith direction is a direction perpendicular to the aforementioned horizontal reference plane).

[0039] The receiving antenna 111 is advantageously realized by a predetermined number of antennas, which antennas are: - have predetermined operating characteristics (direction, gain, antenna pattern or radiation / power pattern, etc.), Jammer 1 is installed / attached in place, -Pointing is performed according to the specified pointing direction. Here, the predetermined number, the predetermined operating characteristic, the predetermined position, and the predetermined pointing direction guarantee the aforementioned elevation angle coverage range and azimuth angle coverage range (or, more generally, the elevation angle range and azimuth angle range of interest).

[0040] Advantageously, the receiving antenna 111 is a directional antenna, preferably one with high gain.

[0041] Furthermore, preferably, said receiving antenna 111 has suitable characteristics in terms of weight and bulkiness to enable or in any case facilitate the incorporation / installation of said receiving antenna 111 into / onto the jammer 1.

[0042] FIG. 3 shows a schematic example of the pointing of the receiving antenna 111 for detecting satellite SAR signals.

[0043] Specifically, Figure 3 shows · vertical axis z corresponding to the zenith direction of jammer 1; two horizontal axes x and y, which are mutually orthogonal and perpendicular to the axis z, and which define a given horizontal reference plane of said jammer 1, whereby this given horizontal reference plane of said jammer 1 is positioned at the intersection O of said axes x, y, z (the origin of the so-called 3D Cartesian reference system); denotes the three-dimensional (3D) Cartesian reference system defined by

[0044] Furthermore, FIG. 3 shows schematically the pointing directions of the four groups of receive antennas 111 together with their respective radiation patterns.

[0045] Specifically, FIG. 3 shows four groups of receive antennas 111 oriented in four quadrants in azimuth (to ensure 360° azimuth coverage around the zenith direction) and in elevation corresponding to typical illumination directions of SAR satellites.

[0046] In this regard, it is important to note that, depending on the threat type of interest, the pointing of the receive antenna 111 can be advantageously redefined in an appropriate manner to focus on a particular sector (and therefore threat) or to accommodate a sector common to multiple types of threats. Furthermore, the pointing can advantageously be further gradient to achieve coverage against avionics threats in diving motion and / or to provide coverage with maneuvers that are quasi-orthogonal to the jammer 1.

[0047] Referring again to the example shown in Figure 3, Figure 4 also shows a schematic representation of one embodiment of each group of receive antennas 111. Advantageously, each group of receive antennas 111 is realized by three horn antennas (respectively designated 111A, 111B, and 111C), which ensure full band coverage for typical frequencies of a satellite SAR sensor / system.

[0048] Finally, with regard to the receiving antennas 111, it should be noted that the use of four groups of receiving antennas 111 as in the example just described not only ensures elevation and azimuth coverage of interest, but also makes it possible to achieve a rough estimate of the direction of arrival of the RF signal, thereby making it possible to properly point the RF jamming means 12 towards a detected threat even in the absence of intelligence data regarding satellite orbits or aircraft (e.g., drones, airplanes, etc.) flight trajectories.

[0049] On the other hand, with regard to the RF threat detection unit 112 (which is conveniently implemented by a digital receiver), this RF threat detection unit 112: Detecting the presence of an RF threat based on the RF signal received by the receiving antenna 111 and a predetermined RF threat related library 113; When detecting RF threats, - determining the type of each detected RF threat based on the RF signals received by the receiving antenna 111 and a predetermined RF threat association library 113; - estimating the direction of arrival of each detected RF threat based on the RF signals received by the receiving antenna 111; - alerting a control system 13 about detected RF threats, thereby providing said control system 13 with each type of detected RF and each direction of arrival of said detected RF; It is configured as follows.

[0050] In this regard, it is important to note that the predetermined RF threat-related library 113 includes (i.e., stores) information about one or more RF threats of interest (e.g., SAR sensors / systems, radar sensors / systems, or more generally, RF remote sensing sensors / systems) so that the RF threat detection unit 112 can detect the presence of the RF threats of interest and determine the respective types of the RF threats of interest based on the RF signals received by the receiving antenna 111.

[0051] Preferably, the predetermined RF threat related library 113 includes: Related to various types of RF threats of concern, indicating the operational parameters (e.g., frequency, pulse repetition interval (PRI), pulse width, agility, etc.) of each of said RF threats of interest; Contains (i.e., stores) information and / or data.

[0052] Figure 5 shows a block diagram outlining the high-level functional architecture of control system 13. This control system 13 includes: a control unit 131; one or more predetermined RF jamming action related libraries 132, which may conveniently be stored in a memory internal to the control system 13; and Equipped with.

[0053] More specifically, when the RF threat detection unit 112 detects an RF threat, the control unit 131 determining RF jamming actions to be taken against the detected RF threats based on their respective types determined by the RF threat detection unit 112 and a predetermined RF jamming action association library 132; activating the RF jamming means 12 (providing the RF jamming means 12 with appropriate commands that are indicative, among other things, of the direction of arrival of the RF threat estimated by the RF threat detection unit 112), thereby causing said RF jamming means 12 to perform the determined RF jamming action against the detected RF threat; It is configured as follows.

[0054] In this regard, it is important to note that the predetermined RF jamming action related library 132 includes (i.e., stores), for each RF threat of interest inserted / suggested / defined in the predetermined RF threat related library 113, respective information regarding one or more respective RF jamming actions to be performed against the RF threat of interest.

[0055] Preferably, the predetermined RF jamming action association library 132 includes, for each RF threat of interest inserted / suggested / defined in the predetermined RF threat association library 113: Respective information and / or data relating to one or more respective RF jamming techniques (preferably the most appropriate and effective jamming techniques) to be implemented against said RF threats of interest; and Respective information and / or data indicative of respective operational parameters used to implement said respective RF jamming techniques against said RF threats of interest, wherein advantageously said respective operational parameters are characterized by the following: - the noise band to be used, - the number of jamming pulses to be generated for each received SAR / radar / RF pulse; - the amplitude modulation to be used, - What frequency modulation should be used? and the respective information and / or data relating to one or more of the following: Contains (i.e., stores)

[0056] 6 shows a block diagram illustrating a high-level functional architecture of RF jamming means 12, which is operable by control system 13 (specifically, by control unit 131) when RF threat detection means 11 (specifically, by RF threat detection unit 112) detects an RF threat; A plurality of transmitting and receiving antennas 121, - similarly achieves the same elevation and azimuth coverage as the receiving antenna 111; - tracking detected RF threats (conveniently by receiving RF signals coming from the detected RF threats); transmitting RF jamming signals against the detected RF threats to implement corresponding RF jamming actions determined by the control system 13 (specifically by the control unit 131); A plurality of transmitting and receiving antennas 121 configured as follows: an RF jamming signal generating unit 122, preferably of the Digital Radio Frequency Memory (DRFM) type, configured to generate an RF jamming signal to be transmitted by the transmitting / receiving antenna 121 against the detected RF threat in order to perform the corresponding RF jamming action (conveniently after storing and processing the RF signal received by the transmitting / receiving antenna 121 and coming from the detected RF threat); Equipped with.

[0057] Advantageously, the transmitting and receiving antenna 121 comprises: High gain and High capabilities (especially regarding agility, flexibility and precision) for pointing the transmit and receive beam and therefore targeting detected RF threats; This is to achieve the following.

[0058] Preferably, the transmit and receive antenna 121 is made up of an Active Electronically Steered Antenna (AESA), sometimes also called an Active Electronically Scanned Array (AESA).

[0059] Preferably, the jammer 1 comprises or is coupled to a mechanical pointing system configured and operable to change the elevation pointing of the receiving antenna 111 and the transmitting / receiving antenna 121 to modify the elevation coverage range of the jammer 1.

[0060] Advantageously, the mechanical pointing system is configured and operable to change the slope of the entire jammer 1 to change the elevation pointing of the receiving antenna 111 and the transmitting / receiving antenna 121 and thus modify the elevation coverage range of the jammer 1.

[0061] In contrast, with regard to the user interface means 2, this user interface means 2 advantageously allows the user / operator to: -Monitoring and controlling the operation of Jammer 1, Define / set the elevation angle coverage range of the jammer 1, i.e., of the receiving antenna 111 and the transmitting / receiving antenna 121 (specifically, by defining / setting the given minimum and maximum elevation angles as mentioned above); defining, programming, configuring, modifying, etc., predetermined RF threat-related libraries 113 and predetermined RF jamming action-related libraries 132; Operate the mechanical pointing system to change / correct the elevation range of Jammer 1 It is configured to be able to do this.

[0062] In view of what has just been explained, it is also possible to define a jamming system comprising a jammer 1 and a user interface means 2 (and, in the case of a mechanical pointing system external to said jammer 1, also said mechanical pointing system).

[0063] FIG. 7 shows one embodiment of a jammer 1 for use on a naval platform to detect and nullify satellite SAR signals.

[0064] Specifically, in this embodiment, the transmit / receive antenna 121 dedicated to delivering jamming signals is realized by two pairs of AESAs 121A, 121B, Each pair of AESAs, 121A and 121B, operates in its own frequency band. For each pair, each of the two AESAs 121A or 121B of the pair provides an azimuth coverage of 90°, thereby providing a total azimuth coverage of 180° for each pair.

[0065] Furthermore, the receiving antenna 111 dedicated to satellite SAR threat detection comprises multiple groups of antennas, which also provide a total azimuth coverage of 180°. Advantageously, each antenna group is realized by three horn antennas of the type shown in FIG. 4 and described above (i.e., horn antennas 111A, 111B, 111C).

[0066] Advantageously, a 45° polarizer may be used to further advantage.

[0067] Thus, by using a jamming system with two jammers as embodied by the example shown in Figure 7 and just described, and a jammer appropriately installed / mounted relative to the other jammer located on the same naval platform, it is possible to achieve a total azimuth coverage of 360° around the zenith axis of the jamming system for both detecting satellite SAR threats and delivering jamming signals to counter such threats.

[0068] In this regard, it is important to note that the embodiment shown in Figure 7 and just described should in no way be construed as limiting, much less restrictive. In offshore fields, either for naval or coastal installations; and In land-based fields for either fixed or mobile installations It can be used to advantage.

[0069] In particular, depending on the type of mission of interest, Jammer 1 can also be advantageously customized and scaled to meet different requirements (and not just equipment requirements) typical of different application scenarios.

[0070] In the example shown in FIG. 7, ie in the case of the anti-satellite SAR configuration of jammer 1, jammer 1 advantageously provides protection from low earth orbit satellite platforms.

[0071] In this case, a fast reaction is preferred, since the moment of illumination by the SAR sensor is unknown and the sensor moves very fast in its orbit.

[0072] A fast response is therefore important because the SAR integrates the signal during the monitoring period, so that the jamming signal must act from the beginning to the end of the illumination window to be maximally effective.

[0073] Thus, in use, the RF threat detection means 11 has the task of intercepting pulses from the electromagnetic environment, recognizing pulses that belong to a potential RF threat of interest (e.g., in the case of a SAR threat), roughly estimating the direction of arrival, and then alerting the control system 13 by providing the estimated direction of arrival to the control system 13, thereby activating the delivery of jamming via the RF jamming means 12. Initially, it is advantageous to prioritize jamming signal delivery speed over the accuracy of the RF threat direction of arrival measurement / estimation. Advantageously, fine-tuning of the direction of arrival measurement / estimation can then be performed during jamming signal delivery to maximize both the pointing accuracy of the RF jamming means 12 (specifically of each transmit / receive antenna 121) and the power level of the delivered jamming signal.

[0074] This effect can also be felt to some extent when compared with avionics platforms. Specifically, in the case of aircraft sensors, the illumination times are sometimes significantly longer, so the visibility period is longer than in the case of satellites. However, sometimes, for example, in the case of an avionics platform approaching a protected target, the situation is similar to that of satellites, as the beneficial times for effective delivery of jamming signals are reduced.

[0075] Furthermore, in various usage scenarios, the process gain issues of the imaging sensor remain typically larger than those of the "typical" sensor.

[0076] SAR waveforms typically consist of linear (chirp) frequency-modulated (FM) pulses with a fairly wide bandwidth to achieve resolution in the azimuth range, which, in addition to the long range, places further constraints on the detection technology.

[0077] The limitations that typically remain in these situations are overcome by this jammer 1 through the use of a receive antenna 111 dedicated to detecting SAR signals, oriented to ensure coverage within a desired elevation sector, which also makes it possible to ensure coverage against other categories of RF threats that originate at particularly high elevation angles.

[0078] 8 and 9 show an example of a satellite SAR image and a corresponding example SAR image, respectively, acquired in the presence of jamming signals delivered by jammer 1 in the satellite SAR countermeasure configuration described above.

[0079] From the foregoing disclosure, the numerous innovative features and numerous technical advantages of the present invention will be immediately apparent to those skilled in the art.

[0080] Specifically, the jamming device according to the present invention comprises two subsystems: a receiving subsystem dedicated to threat detection that reactively alerts when illuminated by a threat arriving from an atypical elevation angle of arrival; a jamming subsystem that prevents manipulation of enemy sensors from extracting sensitive information (e.g., imaging information or angular and range coordinates of one or more targets); and It is important to point out that this is based on cooperation between the two parties.

[0081] The proper mechanical construction and proper orientation of the antenna optimizes the jamming device's ability to detect incoming radar transmissions from these classes of sensors and maximizes contrast effectiveness. The threat characteristics and most appropriate jamming strategies are advantageously determined, tailored, and managed on a library-based basis according to the ongoing mission.

[0082] The architecture of the jamming device makes it possible to best meet particularly urgent mission requirements, allowing the device to be advantageously used not only for counter-SAR applications but also for protection against diving threats, or in any case with a quasi-zenith flight profile and high kinematic evolution.

[0083] Furthermore, the architecture of the jamming device according to the invention allows deep integration between the two aforementioned subsystems and makes it possible to use the latest transmission and processing technologies, which makes the architecture particularly reactive and flexible, in addition to ensuring maximum effectiveness of the delivered contrast.

[0084] These features are useful in all their application scenarios, where the speed of response, the power used, and the effectiveness of the jamming delivered are fundamental.

[0085] The jamming device according to the invention arises from the applicant's extensive knowledge of jamming radar systems, which require the use of panoramic receivers with high probability of interception, fast reaction times and coherent jamming signal delivery.

[0086] The present invention can meet urgent electronic defense requirements against either satellite SAR sensors or, more generally, a variety of avionics-type RF threats from high elevation angles (up to near-zenith profiles).

[0087] Furthermore, the use of modern DRFM devices, such as those by the applicant, allows the jamming device to deliver a wide variety of possible coherent jamming strategies and to synthesize effective jamming strategies very quickly.

[0088] Furthermore, the jamming device according to the invention is characterized by a highly flexible control architecture.

[0089] More specifically, the subsystem dedicated to this jamming delivery includes: Acting in real time against RF threats, reducing processing losses in enemy sensors and therefore increasing the effectiveness of defenses; It operates on a pulse basis, thus allowing the radar sensor transmission to maintain consistency at each point in time; - Operates on a modulation basis, making it possible to control the characteristics and therefore the effectiveness of jamming signals sent to enemy receivers.

[0090] In implementation, this means: Increased effectiveness of delivered jamming signals and therefore the resulting denial of the ability of enemy sensors to extract relevant information; The ability to control the jamming distribution in the resulting image (SAR or more generally radar) This results in:

[0091] Currently known conventional naval and ground-based electronic defense systems are not designed to provide elevation coverage suitable for defending against zenith- or quasi-zenith-type satellite or avionic SAR threats. Indeed, conventional configurations of such systems typically provide elevation coverage of [-5°, +55°]. In contrast, a jamming device according to the present invention can provide coverage at high elevation angles, even at zenith or quasi-zenith elevation angles. Furthermore, in accordance with a preferred embodiment of the present invention, the jamming device may advantageously include or be coupled to a mechanical pointing / tilting system capable of orienting the antenna or the entire jamming device toward a desired pointing direction, even in real time, and maintaining it fixed throughout the mission. This directivity is also effective in detecting and neutralizing SAR threats located on hostile avionic platforms that also operate near these field of view angles.

[0092] Advantageously, a further configuration may include positioning these antennas so that when the jamming devices are appropriately tilted, the final pointing is in a quasi-zenith direction to ensure coverage of the sector located at the zenith.

[0093] The above-mentioned series of technical features make the use of the jamming device according to the present invention particularly advantageous for neutralizing both satellite SAR sensors and avionic SAR sensors, as well as airborne RF threats with diverse radars or different flight profiles, since it is able to meet the typical requirements of both types of operation scenarios.

[0094] actually, In the case of protection against satellite SAR, the use of a jamming device according to the invention is advantageous, since it has a high reactivity, which, combined with the possibility to program, modify and therefore use different jamming techniques, ensures a high operational efficiency and effectiveness of the device, which is always able to neutralize the satellite SAR threat and offset the high processing gain of the SAR receiver. In the case of protection against avionic SAR (for example installed on aircraft, drones, etc.), the use of a jamming device according to the invention is advantageous, since such a device has a flexible architecture that allows it to be programmed, modified and therefore to use highly effective contrast techniques. This ensures that an effective electronic defense is delivered, since the detectability of SAR-type threats is always guaranteed. In the case of defense against avionic RF threats with a zenith profile, a quasi-zenith profile or, more generally, with a high field of view, the use of a jamming device according to the invention is advantageous, since such a device allows the field of view to be configured by a mechanical pointing system, and therefore always allows a configuration suitable for ensuring coverage for a zenith elevation sector or an elevation sector close to 90°. This ensures the delivery of electronic defenses that are either efficient or effective, because: - Ensures the ability to detect threats with zenith or quasi-zenith flight profiles; - Fast response delivery guaranteed - Effective jamming techniques will become available.

[0095] Finally, it is important to reiterate that the present invention makes it possible to equip naval or terrestrial platforms with electronic defense systems that are highly effective against satellite or avionic SAR threats and, more generally, against various types of avionic RF threats at high viewing angles.

[0096] In fact, the jamming device according to the invention: Various mission categories, i.e. - Satellite SAR countermeasure mission, - Platform counter-avionics missions, and - More generally, it can provide an effective countermeasure against radars (with imaging or other high processing gains) on airborne platforms located at elevation angles up to the zenith (depending on the mission configuration). and Rapid response to various types of threats - Provides a receiving subsystem specialized in detecting threats of interest, - Furthermore, a jamming subsystem for delivering interference will be integrated into the same device. By doing so Secure, Preferably, a mechanical pointing system is provided, whereby - Maximize or optimize elevation coverage, - Optimizing the power of the transmitted jamming signals; It becomes possible to Enables high threat tracking and maximizes delivered jamming power, -Highly flexible control architecture.

[0097] Finally, it is important to note that although the invention described above makes particular reference to very specific embodiments, this should not be construed as a limitation to such embodiments, and that the scope of the invention includes any variations, modifications, or simplifications that fall within the scope of the appended claims. [Explanation of symbols]

[0098] 1 Jamming device, jammer 2. User Interface Methods 11 RF Threat Detection Methods 12 RF jamming means 13 Control System 111 Receiving antenna 111A Horn Antenna 111B Horn Antenna 111C Horn Antenna 112 RF threat detection unit, RF threat detection means unit 113 RF Threat Related Library 121 Transmitting and receiving antenna 121A AESA 121B AESA 122 RF jamming signal generating unit 131 Control Unit 132 RF Jamming Action Related Libraries

Claims

1. A jamming device (1) for protecting targets on the Earth's surface from high-frequency threats of the space, satellite or aircraft type, comprising: The jamming device (1) High frequency threat detection means (11), A radio frequency jamming means (12), and a control system (13); Equipped with The high frequency threat detection means (11) a plurality of receiving antennas (111); a radio frequency threat detection unit (112); and one or more predetermined radio frequency threat related libraries (113); Equipped with the receiving antenna (111) is configured to receive radio frequency signals having an elevation angle of arrival that is equal to or greater than a given minimum elevation angle, thereby achieving an elevation angle coverage range of interest; The radio frequency threat detection unit (112) Detecting the presence of a radio frequency threat based on the radio frequency signal received by the receiving antenna (111) and the predetermined radio frequency threat related library (113); When detecting high frequency threats, determining the type of each of the detected radio frequency threats based on the radio frequency signals received by the receiving antenna (111) and the predetermined radio frequency threat related library (113); estimating the direction of arrival of each of the detected radio frequency threats based on the radio frequency signals received by the receiving antenna (111); Alerting the control system (13) about the detected RF threats, thereby providing the control system (13) with the type and direction of arrival of each of the detected RF threats. It is configured as follows: the predetermined RF threat-related library (113) includes information related to the RF threats of interest such that the RF threat detection unit (112) can detect the presence of one or more RF threats of interest and determine the type of each of the RF threats based on the RF signals received by the receiving antenna (111); The control system (13) a control unit (131), and one or more predetermined radio frequency jamming action related libraries (132); Equipped with When the high frequency threat detection unit (112) detects a high frequency threat, the control unit (131) determining a radio frequency jamming action to be performed on the detected radio frequency threat based on the respective types determined by the radio frequency threat detection unit (112) and the predetermined radio frequency jamming action association library (132); operating the radio frequency jamming means (12) such that the radio frequency jamming means (12) implements the determined radio frequency jamming action against the detected radio frequency threat; It is configured as follows: the predetermined radio frequency jamming action association library (132) includes, for each radio frequency threat of interest inserted into the predetermined radio frequency threat association library (113), respective information regarding one or more respective radio frequency jamming actions to be performed against the radio frequency threat of interest; The radio frequency jamming means (12) is operable by the control unit (131) when a radio frequency threat is detected by the radio frequency threat detection unit (112); A plurality of transmitting and receiving antennas (121), Further realizing the elevation angle coverage range of interest; tracking the detected radio frequency threat; Transmitting a radio frequency jamming signal to the detected radio frequency threat to implement the radio frequency jamming action determined by the control unit (131). A plurality of transmitting and receiving antennas (121) configured as follows: a high frequency jamming signal generating unit (122) configured to generate the high frequency jamming signal to be transmitted by the transmitting / receiving antenna (121) to the detected high frequency threat in order to perform the high frequency jamming action; A jamming device (1).

2. the receiving antenna (111) is configured to receive a radio frequency signal having an arrival elevation angle included in a given elevation angle range defined by the given minimum elevation angle and a given maximum elevation angle greater than the given minimum elevation angle; The jamming device of claim 1 , wherein the given elevation angle range corresponds to the elevation angle correspondence range of interest.

3. 3. The jamming device according to claim 1, wherein the given minimum elevation angle is equal to or greater than 20 degrees.

4. The jamming device of claim 2 , wherein the given minimum elevation angle is between 20° and 65°, and the given maximum elevation angle is between 40° and 90°.

5. The receiving antenna (111) is configured to receive high frequency signals having the elevation angle and azimuth angle of arrival within a range of 0° to 180° or 0° to 360°, and the receiving antenna (111) provides an azimuth angle coverage range of 180° or 360° centered on the zenith direction of the jamming device (1); 5. The jamming device according to any one of claims 1 to 4, wherein the transmitting and receiving antenna (121) is configured to further achieve the azimuth coverage.

6. The predetermined radio frequency threat related library (113) comprises: Related to various types of radio frequency threats of concern, indicating operational parameters for each of said radio frequency threats of interest; Contains information and / or data, The predetermined RF jamming action-related library (132) includes, for each RF threat of interest inserted into the predetermined RF threat-related library (113): associated with one or more respective radio frequency jamming techniques to be implemented against the radio frequency threat of interest; indicate respective operational parameters to be used to implement the respective RF jamming techniques against the RF threat of interest; Jamming device according to any one of claims 1 to 5, comprising respective information and / or respective data.

7. changing the elevation pointing of the receiving antenna (111) and the transmitting / receiving antenna (121) to modify the elevation coverage range of interest; or Changing the gradient of the entire jamming device (1) to change the elevation pointing of the receiving antenna (111) and the transmitting / receiving antenna (121), thus modifying the elevation coverage range of interest.

7. A jamming device according to claim 1, comprising or coupled to a mechanical pointing system, operable to:

8. The receiving antenna (111) is a horn-type directional antenna, The transmitting and receiving antenna (121) is an active electronically steered high gain antenna; the radio frequency threat detection unit (112) is a digital receiver; Jamming device according to any one of claims 1 to 7, wherein said high frequency jamming signal generating unit (122) is based on digital high frequency memory technology.

9. 9. The jamming device according to any one of claims 1 to 8, wherein the radio frequency threat detection means (11), the radio frequency jamming means (12), and the control system (13) are integrated into a single apparatus / device.

10. 1. A jamming system for defending targets on the Earth's surface from space, satellite, or aircraft type radio frequency threats, comprising: One or more jamming devices (1) according to any one of claims 1 to 9, a user interface means (2) connected to the jamming device (1) for enabling a user / operator to: monitoring and controlling the operation of said jamming device (1); setting the elevation angle coverage range of interest of the jamming device (1); defining and modifying the predetermined radio frequency threat-related library (113) and the predetermined radio frequency jamming action-related library (132) of the jamming device (1); a user interface means (2) configured to enable A jamming system.

11. 10. A jamming system for protecting targets on the Earth's surface from space, satellite or aircraft type radio frequency threats, comprising two jamming devices (1) according to claim 5, each configured to provide a respective azimuth coverage of 180° around a respective zenith direction of said jamming devices (1), said jamming devices (1) being arranged relative to one another so as to collectively provide an azimuth coverage of 360° around the zenith axis of said jamming system.

12. 1. A jamming system for defending targets on the Earth's surface from space, satellite, or aircraft type radio frequency threats, comprising: One or more jamming devices (1) according to claim 7, If a mechanical pointing system is located outside the jamming device (1), then the mechanical pointing system; a user interface means (2) connected to the jamming device (1) for enabling a user / operator to: monitoring and controlling the operation of said jamming device (1); setting the elevation angle coverage range of interest of the jamming device (1); defining and modifying the predetermined radio frequency threat-related library (113) and the predetermined radio frequency jamming action-related library (132) of the jamming device (1); Operate the mechanical pointing system to modify the elevation angle coverage range of interest of the jamming device (1). a user interface means (2) configured to enable A jamming system.

13. A terrestrial or naval platform, either fixed or mobile, comprising a jamming device (1) according to any one of claims 1 to 9 or comprising a jamming system according to any one of claims 10 to 12.

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