Classifications

• • 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
• • 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
  • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
  • G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
  • G01S3/14—Systems for determining direction or deviation from predetermined direction
  • G01S3/58—Rotating or oscillating beam systems using continuous analysis of received signal for determining direction in the plane of rotation or oscillation or for determining deviation from a predetermined direction in such a plane
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
  • G01S13/06—Systems determining position data of a target
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
  • G01S13/867—Combination of radar systems with cameras
• • 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
  • G01S7/021—Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• • 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
  • G01S7/04—Display arrangements

Definitions

• the present invention relates in particular to the field of maritime surveillance and more particularly to a device for detecting and locating mobiles equipped with at least one active radar.
• Maritime surveillance can be conducted from different platforms, such as coast stations, ships or aircraft. These surveillance platforms are always equipped with at least one radar and sometimes radar detectors.
• the radar can detect and locate other platforms, naval or airborne, called targets.
• the goal is to search for undesirable or offending targets in the investigation area.
• the radar detects and locates the targets in its coverage area, by their illumination and the use of backscattered power, or echoes, by the latter.
• the radar detector detects and locates the targets in the environment, indirectly by the emissions of their radars, it is obviously for this reason that they are active.
• the radar antenna performs a 360 ° sweep and, during the passage of the radar antenna towards the target, the radar measures the distance between it and this by measuring the delay time between transmission and reception of the radar signal.
• the radar also measures the bearing of the target by measuring the bearing of the antenna for which the backscattered signal is maximum.
• the target is thus located in distance and azimuth, with respect to the position of the platform, as soon as the antenna passes over the target. With each passing of the radar antenna on the target, the position of the latter is refreshed. This refreshment makes it possible to follow the evolutions of the target and allows its tracking.
• it is not always necessary for the radar to transmit continuously especially if the targets are not very mobile or do not change course, which is the case for ships.
• the fact of transmitting continuously can enable the radar detectors of the other platforms, to detect and locate the presence of the platform. form of surveillance equipped with these radars, and to identify it. The excessive use of radar is therefore an indiscretion.
• the surveillance platform When the surveillance platform is equipped with a radar detector, the latter generally includes a set of antennas that can instantly cover the 360 ° surveillance area in the field. This set of antennas can be formed, for example, by 6 antennas each pointed every 60 ° in the field.
• the installation also includes a box having the functions of reception, analysis, tracking and identification of radar transmissions received over a wide frequency range, for example between 0.5 and 18 GHz.
• This type of sensor is characterized by instantaneous reception on both 360 ° of deposit and on a very wide frequency band. The consequence is a weak antenna gain, usually not exceeding a few dBi.
• This low antenna gain combined with non-optimal signal detection conditions, makes the interception of radars with low radiated peak power (so-called Low Probability of Intercept (LPI) radars) impossible to Operational interest distances. This is even more true for a maritime surveillance aircraft that has horizons related to its flight altitudes.
• LPI Low Probability of Intercept
• an electronic intelligence measurement system comprising a radar and a passive receiver.
• the invention aims to correct all or part of the aforementioned problems by proposing a device for increasing the antenna gain of the radar detectors.
• the subject of the invention is a device for detecting and locating mobiles equipped with at least one radar, said device comprising a radar function comprising an antenna arranged on a rotating structure and a radar emission detector function comprising an antenna part, the device being characterized in that the antenna part of said radar emission detector function is placed on said rotating structure.
• the antenna part of the radar emission detector function, of the device is formed of at least one antenna array delivering as many signals in parallel as there are antennas, all of these signals allowing goniometry on a single radar pulse (monopulse processing).
• the antenna part of the radar emission detector function is an interferometry network.
• the device comprises at least one transmission system between its fixed part and its rotating part and a signal concentration system able to transpose the signals received by the different antennas on a limited number of channels so as to be transmitted. through the transmission system.
• the device comprises a control module able to rotate the rotating structure so as to perform an azimuthal scanning, by the group of antennas of the radar emission detector function, over at least one turn, in order to to locate, in an approximate manner, at least one target radar present in the scanning area of the device.
• control module of the device, is able to orient the antenna group of the radar emission detector function in the direction of a target radar identified after the azimuthal scanning, so as to determine the precise azimuth of said target radar.
• control module of the device is able to orient the antenna part of the radar emission detector function in the direction of a target radar identified after the azimuth scanning, so as to determine the precise scanning law of said target radar.
• the device comprises a control module able to rotate the rotating structure so as to perform an azimuthal scanning, by the radar antenna part of the radar function, over at least one turn, in order to locate, so as to at least one platform equipped with at least one target radar present in the scanning zone of the device and then orienting the antenna portion of the radar emission detector function in the direction of a target radar identified in order to determine the precise azimuth of said target radar as well as its scanning law.
• the device comprises a display system comprising a graphics module able to display a graphic representation of each target radar by a half-line having, for origin, the position of the device for detecting and locating the mobile in the representation. graph, and making an angle, relative to the north direction, equal to the measured azimuth.
• the graphic module makes it possible to represent each target radar by a half-line of color or of a different nature.
• the display system of the device is arranged to display the graphical representations of the target radars identified in superposition with a map obtained during the use of the radar part.
• the main advantages of the invention are to allow an increase in the antenna gain of the radar detectors and an integrated visualization, based on the superposition of the contacts coming from the radar detection and those coming from the radar emission detector.
• the invention also makes it possible to reduce the radar transmission time of mobile detection and location devices and thus greater discretion.
• FIG. 1 shows a block diagram of an exemplary embodiment of the device according to the invention.
• FIG. 2 shows an example of display, on a display device, the results of a search using the device according to the invention.
• FIG. 3 represents an exemplary display, on a display device, of the results of a search using equipment of the radar and radar detector functions of the device according to the invention.
• the present invention relates to a device for detecting and locating mobiles equipped with at least one radar.
• This device can, for example, be on the ground or on board a mobile platform, such as an aircraft or a ship.
• FIG. 1 shows an exemplary embodiment of a device for detecting and locating mobiles according to the invention.
• This device integrates two functions, a radar function 12 and an MRE function 13.
• the antenna 2, of the radar function 12 is mounted on a rotating structure 5 of the device.
• an antenna function can be performed from a linear combination of signals from a set of elementary antennas or radiating elements, so-called beam formation. This can be more or less complicated, fixed or electronically adjustable.
• the device according to the invention comprises at least a pilot 0, a radar transmitter 1, an antenna system 2, 3, a radar receiver 7, an MRE receiver 8, a radar processing unit 9, an MRE processing unit 10 and a display system 1 1.
• the antenna part MRE 3 is mounted on the rotating structure 5 of the device.
• placing the antennal part MRE 3 in the space left free for the evolution of the rotating structure 5 of the radar antenna and the large dimensions of these radar antennas offer the possibility of using MRE antennas. larger than the one currently used today.
• the antenna part MRE 3 is placed on the same side as the radar antenna 2, that is to say with radiation in the same direction or in substantially similar directions. So that their radiation does not interfere, the antenna parts 2, 3 are placed in a substantially vertical plane, one above the other, or one next to the other. In another embodiment, the antenna portion MRE 3 is placed on the opposite side to the radiating face of the radar antenna 2, so that their radiation is in substantially opposite directions.
• the composition of the antennal part MRE 3 depends on the frequency bands corresponding to the radar of the desired targets and the congestion constraints.
• the invention makes it possible to use the volume on the carrier, usually dedicated to the rotating radar to also perform an MRE function.
• it makes it possible to take advantage of the structure of the rotating antenna of the device to add appropriately placed MRE antennas.
• the implantation of the antennal part MRE 3 on the rotating structure of the device avoids the multiplication of antennas in the field and makes it possible to house relatively large MRE antennas with respect to the wavelengths used. This has the advantage of conferring on the antenna part MRE 3 much more gain thus improving the sensitivity of the device and therefore the detectability of low power signals peak radius born.
• the invention also allows easier integration on the carrier platform of the MRE device since the antenna part MRE 3 is installed in the scanning volume of the radar antenna 2.
• the antenna parts 2 and 3 can respectively use several antennas so as to perform goniometries on a single pulse.
• the antenna part 3 of the MRE function 13 is formed of at least one antenna array delivering as many signals in parallel as there are antennas.
• This network of several antennas by delivering a set of signals carrying the information and the precision sought on a single pulse, allows an instantaneous goniometry on a single radar pulse also called monopulse processing.
• This set of antennas, or array of direction finding antennas can give rise to treatments of a power distribution or amplitude in the case of an amplitude direction finding, a phase distribution in the case an interferometry treatment, or an arrival time distribution (or TDOA, for Time Difference Of Arrival).
• the MRE function uses an antenna part formed of two antenna panels, one said to be “right” and the other to be “left”. These two panels, delivering two signals in parallel, allow a simple and very precise direction finding on a single pulse.
• an antenna panel is formed of networks of planar radiating elements having a beam formation synthesizing the equivalent of a single antenna.
• the antenna part 3 of the MRE function 13 is an interferometry network.
• a difficulty in the field of radar detection is the broad frequency band to be covered.
• One solution may be to cut this frequency band into different subbands. This can lead to hardware resources dedicated to each of the subbands. For example, in the case of panel antennas, a specific panel may be dedicated to each subband.
• the latter comprises a transmission system between these two parts.
• This transmission system may, for example, be a rotary joint for high frequency signals or a rotary commutator for low frequency signals.
• the signals of the different channels of the antennal part MRE 3 as well as possibly the signals coming from the radar antenna 2, when it is out of transmission, are separated and sent to a signal concentration system 4.
• This signal concentration system 4 consists in passing the signals received on the different antenna parts 2, 3 on a limited number of channels compatible with the transmission system 6.
• the signals of the different channels of each MRE antenna 3 are transposed to a different frequency channel by mixing the signals with different oscillators whose frequencies are stepped so as to be able to pass the concentrated signal containing the signals. received, on a single channel of the transmission system 6.
• bandpass filters are used to separate the signals and to retrieve the signals from the different antennas.
• the transmission system 6 is a digital optical rotary joint, for example, at high speed.
• the signals received on the different antennas are transposed into baseband and digitally coded by the concentration system 4.
• the signals at the output of the transmission system 6 are then filtered in order to recover the signals coming from each of the antennas, to be processed respectively by a radar receiver 7 and a radar processing module 9 and an MRE receiver 8 and an MRE processing module. 10.
• the bandwidths of the antennas of the antenna part MRE 3 are not wide so as to be able to detect all the possible radars, but are chosen narrower and in relation to the range of frequencies of the radar sought.
• the selected frequency bands may, for example, be the X and S bands.
• the detection and location of mobiles equipped with at least one radar is mainly in two stages.
• the control module of the device rotates its antenna system 2, 3, on to at least one turn, so as to locate approximately the target radars then in a second time the device precisely determines the azimuth of the detected targets.
• this rotation can be limited to one revolution.
• the location of the target radars is performed only by the function MRE 13, the radar function 12 is not active.
• the control module of the device rotates the rotating structure 5 of the device so as to perform an azimuthal scanning of the area to be monitored by the antenna part MRE 3.
• the reception modules 8 and MRE processing 10 identify the different radar emissions present in the scan area of the device according to conventional techniques of MRE functions.
• the high gain of the MRE antennas 3 enables the whole of the MRE function 13 to acquire the radar emissions both on their main lobe and on their diffuse lobes.
• Reception on the main lobe of the target radar makes it possible to improve the knowledge of the basic parameters of the target radar detected, for example its pulse width, its pulse repetition period, its transmission frequency.
• the reception on several main lobes in a row makes it possible to determine the rotation period of the antenna of the target radar and its scanning law.
• the target radars are located approximately in azimuth and the scanning law of their antenna is known.
• the MRE device will refine the azimuthal location of the various detected target radars.
• control module of the detection and location device directs the rotating structure 5 so as to point temporarily the antennal portion MRE 3 in the direction of a target radar to be located at the presumed passage time of the main lobe of the antenna, said target radar, in the direction of the detection device.
• the MRE device selects the antenna part of the sub-band corresponding to the transmission frequency of the target radar.
• the MRE processing module 10 calculates the precise azimuth of the emission the target radar using a monopulse treatment, such as for example and in a nonlimiting manner, by deviation or by interferometry). This calculation is performed from the signals received from the different antennas constituting said panel, and by using a reception filter and an integrator corresponding to the characteristics of the target radar previously established.
• the target radar emission being localized in azimuth, the carrier platform of this target radar is also located.
• the azimuth of the target radar can be used to establish a graphical representation on the display device 1 1, such as a screen.
• the graphical representations of the target radars can be superimposed on a geographical map of the area scanned by the device or a map of the area to be monitored.
• the display system 1 1 has a graphic module capable of displaying a graphic representation of each target radar represented by a half-line 21 a, 21 b originating from the position of the device for detecting and locating mobiles on the geographical map and making an angle, relative to the north direction, equal to the precise azimuth of the measured target radar.
• the graphics module of the display system 11 is arranged to display each localized target radar with a different color graphic representation.
• the display of the half-lines representing the different target radars is of a different nature, for example, a single line or double, a solid line, dashed, dashed or any other equivalent form.
• the operator can deselect the display of some target radars.
• the display device 11 may have means for controlling the display of the graphical representations of the detected target radars. The operator can thus restrict the display to only detected target radars of interest.
• the display system 1 1 may also include a memory zone capable of storing the position of the target radar measured during previous searches.
• the display system 1 1 can thus display the half lines corresponding to the position of a target radar at different times and thus track the displacement of the carrier platform of the target radar.
• each half-line 21 a, 21 b or 22 a, 22 b representing the same radar at different times, has a different origin 20a, 20b.
• the accuracy of this triangulation operation is related to the angular displacement of the carrier of the detection and location device relative to the target radar; the bigger the scroll, the better the accuracy. Consequently, we will seek a displacement of the carrier of the detection device and fast location relative to the target, and non-confused and rather transversal routes.
• the map, displayed on the display device be referenced with respect to a fixed landmark.
• this triangulation operation can make it possible to dispense with the step of determining the target radar precise azimuth.
• a location of the platforms carrying the target radar can be performed by the radar function 12 of the detection and location device and the precise azimuth of each radar, localized carrier platforms, can be determined by the MRE part 13 of the device.
• the operating principle consists of initiating a tactical situation by the radar part 12 of the device and then maintaining this passive tactical situation by the MRE part 13 of the device.
• an azimuthal scanning of the area to be monitored is performed by the radar portion 12 of the detection and location device.
• the control module of the device rotates the rotating structure 5 over at least one turn so that the rotating antenna 2 scans the area to be monitored in order to locate the target platforms present on the scanning zone. .
• the rotation is limited to one revolution in order to limit the transmission time of the radar antenna 2 and thus to minimize the detectability of the detection and localization device.
• the control module of the radar detection and location device rotates the rotating structure 5 so as to temporarily orient the antenna group MRE 3 in the direction of a target radar detected during radar scanning.
• the MRE part 13 will then measure the different parameters of the target radar, such as, for example, the values of pulse width, pulse repetition period and pulse frequency of the radar transmission. This part will also refine the measurement of the azimuth of this target radar.
• FIG. 3 shows an example of display of a radar screen in which the graphical representations of target radars analyzed by the MRE part appear in superposition with the radar map of the targets detected during the use phase of the radar part. 12.
• the visualization of the target radars can be superimposed with the map of the radar tracks extrapolated from the end of the radar emission.
• the operator can thus see, without transmitting, whether the positions obtained by MRE triangulation diverge or not with respect to the extrapolated radar position of the target.
• the operator can thus decide to redo or not a temporary radar emission to refresh the positions of the targets obtained by this means.

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• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• Radar Systems Or Details Thereof (AREA)

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• 2011
  • 2011-09-30 FR FR1102963A patent/FR2980853B1/fr active Active
• 2012
  • 2012-09-04 WO PCT/EP2012/067232 patent/WO2013045231A1/fr active Application Filing
  • 2012-09-04 EP EP12753737.1A patent/EP2761325A1/de not_active Withdrawn
  • 2012-09-04 US US14/348,025 patent/US20150123839A1/en not_active Abandoned

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