EP3729111A1 - Systeme de detection interferometrique de foudre - Google Patents
Systeme de detection interferometrique de foudreInfo
- Publication number
- EP3729111A1 EP3729111A1 EP18839844.0A EP18839844A EP3729111A1 EP 3729111 A1 EP3729111 A1 EP 3729111A1 EP 18839844 A EP18839844 A EP 18839844A EP 3729111 A1 EP3729111 A1 EP 3729111A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- lightning
- antenna
- conductive elements
- electromagnetic
- antenna modules
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
- G01R29/0807—Measuring electromagnetic field characteristics characterised by the application
- G01R29/0814—Field measurements related to measuring influence on or from apparatus, components or humans, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
- G01R29/0842—Measurements related to lightning, e.g. measuring electric disturbances, warning systems
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- 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
- G01S3/46—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
- G01S3/48—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
- H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
- H01Q19/108—Combination of a dipole with a plane reflecting surface
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
- H01Q21/061—Two dimensional planar arrays
- H01Q21/065—Patch antenna array
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
- H01Q21/20—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a curvilinear path
- H01Q21/205—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a curvilinear path providing an omnidirectional coverage
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/30—Arrangements for providing operation on different wavebands
- H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
Definitions
- the invention relates to the field of devices or systems in application with the detection and / or observation of electromagnetic sources.
- Such devices or systems are used for all types of use and preferably but not exclusively, in connection with meteorological phenomena, and more particularly, to provide lightning detection functions, also known by the English name "lightning detection”. ".
- the invention will be described preferentially but not exclusively in the context of prevention against lightning, that is to say in the context of actions aimed at reducing or aborting eventual damage that can cause storms, more particularly, lightning phenomena in territories more or less sensitive than others, such as cultivated areas, or on infrastructures for example.
- Lightning has been the subject of many studies in the field of meteorology, since it has many dangers, which can cause serious damage, both in terms of material and human, such as, for example , the outbreak of fires, a possible electrocution of human beings and / or animals that could potentially lead to their death, electromagnetic interference possibly harmful to communications, aviation and / or navigation, destruction of electronic components in infrastructure and / or equipment.
- lightning consists of a natural phenomenon of discontinuous electrostatic discharge, such a phenomenon generally occurring in regions of storm clouds charged with static electricity, that is to say either in or between such clouds (" Cloud lightning “according to English terminology), or between such clouds and the air or the ground (“ Cloud to Ground (CG) lightning “according to English terminology), the ground may include one or more zones land or sea.
- CG Cloud to Ground
- lightning causes the creation of a plasma, that is to say a medium consisting of a mixture of neutral particles, positive ions and negative electrons, produced in the air on the route of the discharge, resulting in the appearance of two previously mentioned phenomena: on the one hand the lightning, which spreads very rapidly, and on the other hand the thunder, which results from an explosive expansion of the air heated by the lightning, and spreads relatively slowly in comparison with the lightning.
- a plasma that is to say a medium consisting of a mixture of neutral particles, positive ions and negative electrons
- the thunder can resound of a noise, such a crunching, dry and immediate, when the flash is near, or, alternatively, rumble more widely in the distance, more particularly when the storm takes place in a mountainous region, by echo effects in particular. Because light travels much more quickly in the air than sound, lightning is usually visible long before thunder is heard, allowing us to estimate the approximate distance to which lightning has fallen.
- a noise such as a crunching, dry and immediate
- Storm clouds develop from cumulonimbus or cumulonimbus aggregates, also referred to as "storm clouds", such cumulonimbus clouds. which may contain a hundred thousand tons of water, hailstones and small ice crystals.
- the said cumulonimbus are generally subjected to speed shears, that is to say variations of the wind speed as a function of altitude, to directional shears, that is to say variations of the orientation. wind depending on the altitude, and intense ascendances and subsidies.
- This turbulence causes shocks between the particles constituting the cloud, in particular ice crystals and water droplets.
- the redundancy of these clashes leads to the removal of electrons from particles and thus the appearance of charges.
- the heavier particles harbor the negative charges while the lighter ones, supported by the updrafts, are positively charged.
- a complex electrification process leads to the separation of positive and negative electrostatic charges, and thus the creation of an intense electric field.
- an ionized channel is formed, also called a descending tracer, corresponding to the lightning and propagating by successive leaps from the cloud towards the ground.
- the physical processes causing thunderstorms are complex and include many unpredictable elements that are subject to constant change.
- the formation of storms also depends, for many, very variable local conditions, especially in terms of temperature and humidity, soils at the edge of which thunderstorms form, such conditions being more particularly conditioned by the nature of the soil, the type of vegetation, or the configuration of the relief itself depends on the presence of buildings.
- the stormy phenomena are generally sudden, of short duration, ranging from a few tens of minutes to a few hours, and concern relatively limited areas, a few tens of kilometers.
- the detection and location of storm phenomena is particularly complex.
- lightning can be grouped into two main categories: lightning strikes on the ground, also known as “lightning strikes”, and lightning strikes that do not hit the ground. Within these two categories, lightning can be subdivided into other subgroups, as a function, for example, of the specific trajectory of such flashes and / or the direction of the electric current flowing in the light channels associated with each flash. .
- the most common lightning usually does not hit the ground and is commonly referred to as “cloud lightning or intrafloud lightning”.
- Such lightning of lower intensity lightning strikes on the ground, in particular, make it possible to reduce space charge differences in a cloud or between clouds.
- the number of said intra-cloud flashes is a marker of convection of storm cells, well before the appearance of lightning strikes on the ground.
- intra-cloud lightning can provide interesting and important indications for thunderstorms, such as, for example, their rate of growth and / or intensity, leading consequently to important applications in the immediate prediction of thunderstorms.
- one or more intra-cloud flashes precede the first lightning strike, while the storm may have already begun to develop and become electrified.
- a few minutes to a few tens of minutes may elapse between the first intraflat flash and the first lightning strike on the ground.
- This delay may be, in certain cases, essential, since it makes it possible to use the observations made in link with intra-cloud lightning to provide warnings or warnings about lightning strike on the ground, depending on the position of a storm.
- ToA-type geolocation techniques use the constant time difference between the arrival of low frequency signals and sensors positioned on the ground to calculate the location of meteorological events involving lightning strikes on the ground.
- ToA-type geolocation techniques use the constant time difference between the arrival of low frequency signals and sensors positioned on the ground to calculate the location of meteorological events involving lightning strikes on the ground.
- these techniques also present a certain a number of limits and disadvantages, especially in terms of terrain and the effect of conductivity on the speed of propagation of lightning signals.
- each ToA-based detection system identifies a unique and specific function or shape of a signal to provide the most accurate arrival times of the order of one hundred nanoseconds.
- a function or signal form must thus be considered common through a number of systems widely separated from each other, said systems being advantageously networked. Any signal shapes or functions must then be sufficiently separated in time, in order to reduce, or even avoid, the correlation errors between the systems.
- ToA-type detection systems are very sensitive in terms of signal-to-noise ratio.
- Interferometry consists of a measurement method exploiting the phase difference of a coherent electromagnetic wave, the phase then being measured by two receivers at two distinct points.
- the use of interferometry is particularly clever, since interferometry-based detection systems do not require a specific form of signal and operate relatively easily on noisy signals.
- Figure 1 shows a first example implementation of a known system for detecting an electromagnetic source by interferometry, already available on the market.
- Such a known system 1 for detecting an electromagnetic source aims to capture the lightning totally, whether it is intra-cloud lightning and / or lightning striking the ground, since it exploits a only high frequency interferometry technologies to detect intra-cloud lightning, but also technologies with magnetic orientation and low-frequency arrival time to detect lightning strikes on the ground.
- Said detection system 1 consists of an unambiguous network, such a system or network being advantageously arranged to operate at very high frequencies, that is to say in frequency bands between one hundred eleven (111) and one hundred and ten seven (117) megahertz.
- said system 1 comprises at least five conductive elements in the form of five dipoles 2.
- the system 1 is thus described as unambiguous, that is to say that the distance between the dipoles is less than half a wavelength, such a distance depending on the coupling terms between the dipoles.
- said detection system 1 comprises a central portion 4, cooperating with each of the dipoles 2 respectively by means of an advantageously dimensioned dielectric element.
- the five dipoles 2 of said system 1 are advantageously positioned equidistant from said central portion 4.
- the latter is furthermore arranged to cooperate with a low-frequency sensor, said sensor using technologies with magnetic orientation at arrival time ( ToA) and / or magnetic gonometry at low frequency, said sensor being arranged to detect or locate lightning strikes.
- a central portion 4 may also be configured to cooperate simultaneously and severally with a GPS location-based receiver system (for "Global Positioning System” in English terminology), thus enabling synchronization, calibration and calibration. other detection systems positioned at other places of interest and spatially separated.
- the detection system 1 optionally comprises a mast 3 arranged to cooperate solidarily, that is to say according to a suitable mechanical connection, for example of the embedding type, the central portion 4 and also the detection elements of the system.
- a mast 3 makes it possible in particular to position the system 1 for detecting an electromagnetic source at various locations of particular interest, particularly at the top of the infrastructure.
- a known system 1 comprises at least five conductive elements in the form of five dipoles.
- Such a system can thus be slightly redundant, since certain detections can provide identical information, resulting in identical or even superfluous treatments.
- the particular architecture or arrangement of such a system for detecting a known electromagnetic source, such as that described with reference to FIG. 1 imposes on said system to be implanted at the culmination point of the structure or of the infrastructure over which it is positioned.
- a system for detecting an electromagnetic source in the form of a network is advantageously arranged to operate at very high frequencies, that is to say in frequency bands. between one hundred eleven (111) and one hundred and seventeen (117) megahertz. Operating such a frequency band imposes a dimensioning accordingly the detection system and thus leads to the design of a cumbersome and heavy system.
- the system in the form of an antenna array has the shape of a cylinder whose dimensions are substantially of the order of one hundred and twenty centimeters in diameter and one hundred and twenty centimeters in height.
- the system is thus complex to install and / or maintain and not adapted for some installations and / or often existing infrastructures.
- the arrangement of said system requires that no metal object can be positioned around the system at a distance substantially less than ten times the wavelength.
- the invention thus makes it possible to respond to all or some of the disadvantages raised by the known solutions.
- a system for detecting an electromagnetic source comprises two physically dissociated antenna modules, each an antenna module comprising two conductive elements, a planar reflector having a first face and a second face, said first faces of the planar reflectors of said antenna modules cooperating respectively and severally with said two conductive elements of said antenna modules, the two modules antenna being mutually arranged so that the second faces of their planar reflectors form a salient angle.
- the planar reflectors of the antenna modules of a system for detecting an electromagnetic source by interferometry according to the invention can be respectively oriented to be substantially vertical.
- the two conducting elements of each antenna module of said system can advantageously be dipoles.
- the two elements conductors of each antenna module of the latter may have quadrilateral conductive surfaces.
- the two conducting elements and the plane reflector of each antenna module of the latter can cooperate with the means of a dielectric element.
- each antenna module of a system for detecting an electromagnetic source by interferometry may consist of a metal mesh.
- a system for detecting an electromagnetic source by interferometry may comprise four physically dissociated antenna modules, each module being antenna comprising two conductive elements, a plane reflector having a first face and a second face, said first faces of the planar reflectors of said antenna modules cooperating respectively and severally with said two conductive elements of said antenna modules, the four modules of antenna being mutually arranged so that the second faces of their planar reflectors form, two by two, an angle of ninety degrees.
- each antenna module of said system in order to ensure optimum detection, and in particular to increase its accuracy, for example by avoiding unwanted pollution induced by other third-party electromagnetic sources, can be arranged to detecting an electromagnetic source producing an electromagnetic wave whose frequency band is selected from the set of frequency bands: between 111 and 117 megahertz, between 328.6 and 335.4 megahertz or between 1400 and 1427 megahertz.
- each antenna module of a system for detecting an electromagnetic source By interferometry according to the invention can be arranged to simultaneously receive a plurality of frequency bands.
- FIG. 1, previously described, illustrates an exemplary embodiment of a known lightning detection system
- FIG. 2 illustrates a schematic view of a first embodiment of a system for detecting an electromagnetic source by interferometry according to the invention
- FIGS. 3A and 3B show two schematic views of a second embodiment of a system for detecting an electromagnetic source by interferometry according to the invention
- FIG. 4A, 4B and 4C show schematic respective views of non-limiting embodiments of antenna modules of a system for detecting an electromagnetic source by interferometry according to the invention.
- Figures 2, 3A and 3B respectively show first and second embodiments of a system for detecting an electromagnetic source by interferometry according to the invention.
- electromagnetic source also referred to as a "radio source” any source or more generally any element capable of emitting an electromagnetic field, such an electromagnetic field comprising one or several electromagnetic waves.
- the best-known electromagnetic wave remains the light wave.
- Such electromagnetic sources, and more generally such electromagnetic fields may advantageously be of natural origin, such as those at the origin of lightning or lightning, or created by human activity, such as those at the source of origin of x-rays used in radiography.
- the invention will be described through an example of a preferred but non-limiting application in which the electromagnetic source consists of lightning or even one or more lightning.
- indiscriminately expressions "lightning” and “lightning” to define the electrostatic phenomenon observed by a system according to the invention.
- interferometry is understood to mean any measurement method making it possible to detect an electromagnetic source and / or an electromagnetic field as mentioned above, exploiting the phase difference of a coherent electromagnetic wave, the phase being then measured by two receivers at two distinct points, thus making it possible to evaluate the phase shift.
- the use of interferometry-based systems is particularly clever, since methods based on interferometry have the advantage of operating independently of the shape of the electromagnetic wave or waves radiated by lightning or lightning, increasing the robustness of the systems with regard to the deformations that can undergo the wave or waves. The accuracy of the location of an electromagnetic source is thus not dependent on the environment and / or the distance separating the system from the lightning or flashes.
- such systems based on interferometry are particularly effective for a large number of electromagnetic sources to observe and thus provide real-time information, unlike systems based on ToA techniques.
- the ToA technologies impose to have knowledge a priori on forms of the electromagnetic waves to be observed and are limited in their use by the distances between the sensors composing a system of study, since the measurements of arrival time are limited by the travel time of distances between sensors of the same system.
- the order of the electromagnetic waves can be possibly reversed or changed, directly impacting the measurements and consequently the location of the electromagnetic waves.
- the principle of interferometry consists mainly in calculating the direction of an electromagnetic source by measuring the phase shift of one or more electromagnetic waves originating from the same source during their propagation, the measurement being carried out by means of a or several conductive elements.
- the equation defining any detection or measurement performed and / or performed by a conductive element or dipole of an interferometric system, composed of at least two conductive elements or dipoles, is given by the following formula:
- f is the elevation, that is the angle between a horizontal plane defined by the ground and the direction of the electromagnetic source
- l is the distance between two conductive elements
- Q is the azimuth, that is, the angle in the horizontal plane between the direction of the magnetic source and a reference direction;
- F is the phase shift, that is to say the phase difference at the same time determined between two signals describing the electromagnetic wave per two conductive elements.
- Such an equation shows a relation between said phase shift F of an electromagnetic wave and the azimuth Q and the elevation f, to locate the electromagnetic source.
- the accuracy of such a location is only a function of the accuracy of the phase shift measurement, the accuracy of such a phase measurement depending solely on the signal level relative to the electromagnetic wave received and the integration time, that is to say the period of time during which the receiver must be exposed to the electromagnetic wave or the period of comparison time of the respective phases of the two signals coming from two conductive elements, thus making it possible to reduce or even remove the measurement noise, in this case between ten to a few hundred microseconds.
- such a system based on interferometry will preferably but not exclusively be used to detect one or more electromagnetic sources, in this case for the detection of lightning, one or more lightning.
- a system 1 for detecting an electromagnetic source by interferometry in accordance with the invention comprises two antenna modules.
- Antenna module means any element, object or device, generally metallic and / or electrically conductive, capable of capturing or detecting one or more electromagnetic waves in space.
- Such an antenna module is thus considered as a juxtaposable or combinable element with other elements of the same nature or contributing to the same function, that is to say to one or more other antenna modules, able to detect one or more electromagnetic waves, making it possible to solve the interferometry equation and locate a flash.
- All the antenna modules present within a system for detecting an electromagnetic source by interferometry are advantageously physically dissociated, that is to say that they do not have a common mechanical connection between the different modules. antenna.
- Such an arrangement in the form of dissociated antenna modules is particularly advantageous, since said antenna modules are then directional and independent of their supports and therefore not subject to any interference due to their implantation sites.
- at least two antenna modules are necessary to ensure such detection.
- a system 1 according to the invention advantageously comprising two antenna modules dissociated with two conductive elements, can easily locate a flash at a given moment.
- the location of a flash being performed in three dimensions it is thus necessary to perform two phase shift measurements respectively from two different angles. Nevertheless, when several, at least two, flashes, are observable at the same time determined, it may be necessary to use a larger number of antenna modules within the system.
- the invention can not thus be limited to the use of this single number of antenna modules dissociated within a system 1 to detect an electromagnetic source by interferometry according to the invention. Also, the choice of a particular number of conductive elements or more broadly antenna modules with respect to another number, will depend mainly on the number of electromagnetic sources that can or wants to detect and locate concomitantly by a system 1 for detecting an electromagnetic source by interferometry according to the invention.
- the number of antenna modules may also depend on the location of the electromagnetic source (s) to be observed.
- an antenna module comprising N conductive elements can locate Nl sources emitting concomitantly.
- the antenna modules of a system 1 for detecting an electromagnetic source by interferometry according to the invention are dissociated, that is to say that there is no physical and / or mechanical cooperation between the different modules.
- antenna 5 component said system.
- Such dissociation makes it possible to make observations by sector and to simplify the implementation of the systems. Indeed, such a system proves for example particularly effective in areas or on sites where it is not possible to monolithic antenna systems such as that described in connection with Figure 1.
- a system 1 at the Aiguille du Midi site, the summit is already equipped with telecommunication transmitters and can not accommodate a monolithic system.
- a system 1 according to the invention thus allows to install antenna modules dissociated all around the nacelle and thus to overcome the radiation of different transmitters already existing and existing on site.
- said system 1 can be installed around or on any post, such as a pylon type structure.
- each antenna module 5 of a system 1 comprises two conductive elements 2.
- Conduct element means any object consisting mainly of a body, generally but not exclusively a metal, for example aluminum or copper, the physicochemical characteristics of which permit the passage of an electric current, such object being intended to receive all or part of the electromagnetic energy emitted by a flash or more generally by lightning or a radiating source.
- Such conductive elements are advantageously receivers and can thus be described as passive conductive elements.
- the two conductive elements 2 of an antenna module 5 of a system 1 according to the invention can advantageously be separated by a distance substantially between ten and fifty centimeters, preferably twenty centimeters. .
- said conductive elements are advantageously positioned along the same horizon line.
- the presence of two conductive elements advantageously makes it possible to measure a phase shift, thus making it possible to determine the azimuth and elevation of a source electromagnetic generating an electromagnetic wave.
- the invention can not be limited to the number of conductive elements present within each antenna module or the separation distance between such conductive elements.
- One of the aims of the invention is in particular to propose a system for locating an electromagnetic source by interferometry, comprising at least two antenna modules, said system then having a directional emission diagram thus making it possible to overcome the infrastructures or, more generally, supports on which such antenna modules are installed and / or to avoid the coupling between the different antenna modules.
- a coupling between the antenna modules, more particularly the conductive elements imposes a systematic calibration of the detection system, said system being very sensitive to mechanical variations.
- the invention also makes it possible to offer a system for detecting an electromagnetic source by interferometry, comprising at least two antenna modules, said system then having a directional emission diagram thus making it possible to avoid possible reflections of soil.
- each antenna module 5 of a system 1 for detecting an electromagnetic source by interferometry also comprises a reflector 6.
- a reflector 6 Any device capable of reflecting one or more electromagnetic waves.
- such a reflector may be responsible for concentrating the received electromagnetic wave or waves towards the conductive elements.
- such a reflector is preferentially but not exclusively planar.
- such a plane reflector 6 advantageously has a first face 6i and a second face 6ii.
- first and second faces 6i and 6ii make it possible and advantageously the positioning of each dissociated antenna module within the system according to determined distances, of the order of a few centimeters, or even a few meters, to a few tens of meters, so as mentioned above, to overcome the constraints related to the installation of antenna modules, the coupling of conductive elements between said antenna modules and / or ground reflections of electromagnetic waves.
- the planar reflector 6 of each module of FIG. Antenna 5 of the latter may consist of a metal mesh.
- a planar reflector in the form of a metal mesh is particularly advantageous, since such a reflector is relatively light, inexpensive and has a minimum wind catch, said antenna modules being generally installed outdoors and subject to possible weather constraints.
- a metal mesh may have a network or mesh whose dimensions are ten times smaller than the wavelength, to ensure in particular the insulation of the conductive elements.
- the invention can not be limited to the use of a specific arrangement, structure and / or composition of a reflector.
- the choice of a particular arrangement, structure and / or composition of a reflector 6 with regard to another arrangement, another structure and / or another composition may depend, advantageously but without limitation, the electromagnetic source to locate or even more widely the position or location of a system 1 for detecting such an electromagnetic source by interferometry according to the invention in particular to further reduce manufacturing costs, installation and / or maintenance of such a system 1.
- FIGS. 4A, 4B and 4C show respective schematic views of non-limiting exemplary embodiments of antenna modules of a system for detecting an electromagnetic source by interferometry according to the invention.
- FIG. 4A shows a first exemplary embodiment of an antenna module 5 of a system 1 for detecting an electromagnetic source according to the invention.
- the two conducting elements 2 of each antenna module 5 may consist respectively of dipoles.
- any element or receiver object consisting of two metal strands, supplied in its middle 2m, that is to say between such two strands, and intended to receive all or part of electromagnetic energy emitted by a lightning or more generally by lightning.
- the use of conductive elements under the dipole form is particularly clever, since such dipoles are commonly used, so inexpensive, and what is more, easy to implement and insensitive to the coupling between conductive elements.
- FIG. 1 shows a first exemplary embodiment of an antenna module 5 of a system 1 for detecting an electromagnetic source according to the invention.
- the two conducting elements 2 of each antenna module 5 may consist respectively of dipoles.
- any element or receiver object consisting of two metal strands, supplied in its middle 2m, that is to say between such two strands, and intended to receive all or part of electromagnetic
- such coplanar dipoles may advantageously have a substantially trombone shape (also known by the English terminology "folded dipole").
- Dipoles having such a trombone shape offer a number of advantages: firstly, the dipoles, grounded, have no accumulation of capacitive effect and do not require to be discharged. In addition, such dipoles have a better mechanical strength, thus providing a permanent installation over time.
- the conductive elements are in the form of dipoles, as in the example described with reference to FIG.
- the two conductive elements 2 and the reflective plane of an antenna module 5 of a system 1 according to the invention can advantageously be separated from a distance substantially between ten and fifty centimeters, preferably twenty centimeters.
- FIG. 4B shows a second exemplary embodiment of an antenna module 5 of a system 1 for detecting an electromagnetic source according to the invention.
- the two conductive elements 2 of each antenna module 5 may respectively have quadrilateral conductive surfaces.
- such an antenna module 5 comprising two conductive elements 2 having quadrilateral conductive surfaces is considered a planar antenna, also called patch antenna according to English terminology.
- the planar reflector can also be conductive. The use of such antenna modules in the form of planar antennas is particularly advantageous, since such antenna modules, by their very simple design, are very easy to produce industrially.
- said antenna modules in the form of planar antennas have a small footprint compared to other antenna modules, thus allowing easy handling and installations, as well as easy integration against an existing structure, such as a building.
- Such antenna modules in the form of planar antennas just like dipole antennas, have a specific resonance frequency.
- said planar antennas have the advantage of being able to resonate at different frequencies, for example three hundred megahertz and / or one thousand four megahertz.
- Such modules of antennas qualified multi-frequency allow to combine an ambiguous and unambiguous network and thus to increase the accuracy of measurements and to access a localization in three dimensions, even at low elevation.
- the invention can not, however, be limited to the use of a specific conductive element arrangement or structure for the realization of a module antenna.
- the choice of a particular arrangement or structure of conductive element with regard to another arrangement or structure may depend, advantageously but not limitatively, on the altitude or trajectory of the electromagnetic source to be observed and / or locate or even more widely the position or location of a system 1 for detecting an electromagnetic source by interferometry according to the invention in particular to further reduce the costs of manufacturing, installation and / or maintenance of such a system.
- the invention can not be limited to the number of conductive elements present within each antenna module.
- an antenna module of the latter can comprise more than two conductive elements 2, in this case six conductive elements 2.
- the use of a large number of conductive elements within an antenna module makes it possible to refine the directional lobe of the antenna module and thus increase the scope of such a module.
- the first faces 6i of planar reflectors 6 of said antenna modules 5 cooperate respectively and severally with said two conductive elements 2 of said modules antenna 5.
- Such cooperation between the first face 6i of a planar reflector 6 and the two conductive elements 2 may be embodied by any suitable mechanical connection, preferably of embedding type, advantageously permanent or possibly reversible.
- Such an embedding connection can be achieved by any suitable fastening means, said first face 6i of a planar reflector 6 and the two conductive elements 2 being mutually arranged to ensure their assembly.
- the conductive elements when the conductive elements are in the form of dipoles 2, such dipoles can be kept parallel to the reflector 6 by means of respective rectilinear poles describing a "V" association whose base cooperates without degree of freedom with the reflector.
- the invention can not, however, be limited to this single embodiment.
- the invention provides that the first face 6i of a planar reflector 6 and the two conducting elements 2 of a system 1 for detecting an electromagnetic source by interferometry according to the invention can form or consist of one and the same physical entity.
- the invention provides that the two conductive elements 2 and the planar reflector 6, more particularly its first face 6i, of each antenna module 5 of a system 1 for detecting an electromagnetic source by interferometry according to the invention can cooperate by means of a dielectric element 8.
- a dielectric element proves particularly advantageous, since such a dielectric element does not conduct electricity and thus makes it possible to isolate the conductive elements of the first face 6i reflector, so that they can fully perform their function.
- the two conductive elements 2 and the plane reflector 6 of FIG. such an antenna module 5 are advantageously and respectively separated by a dielectric plate, said dielectric plate may consist mainly of an epoxy resin.
- the two antenna modules 5 of the latter are advantageously dissociated, that is to say, preferably but not limited to a few centimeters apart, even from a few meters to a few tens of meters, and mutually arranged so that the second faces 6ii of their planar reflectors 6 form a salient angle, that is to say an angle between zero and one hundred and eighty degrees.
- the conducting elements 2 of said system 1 for detecting an electromagnetic source by interferometry are arranged in such a way that they do not interfere with each other, unlike the antenna system described in connection with
- the second faces 6ii of the respective planar reflectors 6 of the two antenna modules of a system 1 according to FIG. the invention can form an angle substantially equal to ninety degrees, thus ensuring a better resolution and accuracy to finally locate and / or detect one or more electromagnetic sources.
- planar reflectors 6 of such a system 1 can be respectively oriented to be substantially vertical.
- planar reflectors 6 of such a system 1 may be respectively and also oriented to be substantially aligned on the same horizon line.
- the conductive elements of said system 1 for detecting an electromagnetic source by interferometry may also be aligned horizontally, in particular to avoid ground echoes inherent to possible reflections of one or more electromagnetic waves on the ground.
- a system 1 for detecting an electromagnetic source by interferometry may comprise four antenna modules 5, said modules of FIG. antenna 5 being themselves physically and mechanically dissociated from each other, thus allowing the formation of an exploded system or antenna.
- each antenna module 5 may comprise two conductive elements 2, able to measure a phase shift.
- Such conductive elements 2 may also and respectively consist of dipoles or have quadrilateral conductive surfaces.
- Each antenna module of the detection system further comprises a planar reflector 6 having a first face 6i and a second face 6ii, said first faces 6i of planar reflectors 6 of said antenna modules 5 cooperating respectively and severally with said two conductive elements. 2 of said antenna modules 5, possibly by means of a dielectric element.
- the four antenna modules 5 may be mutually arranged so that the second faces 6ii of their planar reflectors 6 form in pairs at an angle of substantially ninety degrees. Arranged in this manner, the four antenna modules of a system 1 according to the invention can then scan an overlapping area of three hundred and sixty degrees.
- Such a configuration not only makes it possible to overcome the infrastructure or more generally the supports on which such antenna modules are installed and / or to get rid of the coupling between the different antenna modules, but also to ensure a wider area of coverage possible to detect an electromagnetic source, ultimately increasing the sensitivity of the system.
- each antenna module of the system can be sized, in order to be able to use several frequency bands.
- each module An antenna 5 of a system 1 for detecting an electromagnetic source by interferometry according to the invention is arranged to detect an electromagnetic source producing an electromagnetic wave whose frequency band is selected from the following set of frequency bands: 111 and 117 megahertz, between 328.6 and 335.4 megahertz or between 1400 and 1427 megahertz.
- the wider the frequency band the lower the noise level.
- a detection frequency band of between 111 and 117 megahertz is particularly advantageous, since the lower the spectral band observed, the better the electromagnetic wave radiates and the better the signal.
- a detection frequency band between 111 and 117 megahertz has the disadvantage of being close to the FM radio transmission and reception (ie emitting in frequency modulation), limiting then the detection ranges.
- the use of a detection frequency band of between 328.6 and 335.4 megahertz or else between 1400 and 1427 megahertz is particularly advantageous, since said emission frequency bands are very restricted, or even forbidden, limiting thus noises or pollution.
- such frequency bands have global coverage.
- the antenna modules have a specific resonance frequency.
- the invention further provides that said antenna modules can be arranged to resonate concomitantly at different frequencies, that is to say to be able to receive concomitantly several, at least two, frequency bands, for example three hundred megahertz and / or one thousand four megahertz.
- Such modules of antennas qualified multi-frequency allow to combine an ambiguous and unambiguous network and thus to increase the accuracy of measurements and to access a localization in three dimensions, even at low elevation.
- such an antenna module may consist of two conductive elements, preferably separated by a distance of approximately one half wavelength, each conductive element having dimensions less than half a wavelength. According to different embodiments:
- the wavelength is substantially equal to one meter.
- the conductive elements of each module are then substantially positioned at fifty centimeters from one another.
- the conductive elements of each module are then substantially positioned at fifty centimeters from one another, for a receiving frequency of one thousand five hundred megahertz, the wavelength is substantially equal at twenty centimeters.
- the conductive elements of each module are then substantially positioned at ten centimeters from one another.
- the wavelength is substantially equal to seventeen centimeters.
- the conductive elements of each module are then substantially positioned at eight centimeters from one another.
- each antenna module of a system for detecting an electromagnetic source by interferometry can not be limited to the frequency bands selected for such detection.
- Such dimensioning and / or adjustment of each antenna module may also depend on the phase excursion, also depending on the coupling effects, of the emission diagram of each antenna module corresponding to a directional lobe and / or any phase ripples, themselves dependent on the frequency.
- a system for detecting an electromagnetic source may also include devices for detecting lightning strikes on the ground, such devices using technologies with magnetic orientation and low-frequency arrival time.
- the invention can not be limited to the application in which the system 1 according to the invention is used.
- such a system for detecting a source Electromagnetic interferometry according to the invention could be used in connection with high voltage lines having one or more sections whose insulation is defective, thus making it possible to anticipate the maintenance of such high voltage lines.
- a system for detecting an electromagnetic source may comprise other accessories, in particular, by way of nonlimiting examples, to allow easy maintenance of the antenna modules on different supports or infrastructures or else processing means for adjusting, calibrating and / or adjusting the measurements.
- Such accessories may be as non-limiting examples, chosen from one or more pre-amplifiers, filters, amplifiers and / or digitizers.
- each antenna module in order to ensure the coherence of each acquisition line of an antenna module and to ensure adequate measurements between the antenna modules of a system for detecting an electromagnetic source conforming to the invention, each antenna module may comprise an emitter positioned between the conductive elements and the reflector plane, in order to regularly calibrate said system.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Geophysics And Detection Of Objects (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1762580A FR3075390B1 (fr) | 2017-12-20 | 2017-12-20 | Systeme de detection interferometrique de foudre |
PCT/FR2018/053482 WO2019122763A1 (fr) | 2017-12-20 | 2018-12-20 | Systeme de detection interferometrique de foudre |
Publications (1)
Publication Number | Publication Date |
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EP3729111A1 true EP3729111A1 (fr) | 2020-10-28 |
Family
ID=62455562
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP18839844.0A Withdrawn EP3729111A1 (fr) | 2017-12-20 | 2018-12-20 | Systeme de detection interferometrique de foudre |
Country Status (6)
Country | Link |
---|---|
US (1) | US20210072338A1 (fr) |
EP (1) | EP3729111A1 (fr) |
CN (1) | CN111788490A (fr) |
FR (1) | FR3075390B1 (fr) |
MA (1) | MA51313A (fr) |
WO (1) | WO2019122763A1 (fr) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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FR3086765B1 (fr) * | 2018-10-01 | 2021-12-10 | Selerys | Procede d'evaluation de la maturite d'une cellule nuageuse et systeme associe |
FR3107771B1 (fr) * | 2020-02-27 | 2022-04-29 | Selerys | Système et procédé de détection et de localisation d’une source de rayonnement électromagnétique |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB853600A (en) * | 1958-07-21 | 1960-11-09 | Alford Andrew | Improvements in antenna systems |
FR1236873A (fr) * | 1958-09-29 | 1960-07-22 | Siemens Ag | Antenne d'émission avec panneaux de dipôles |
FR1387182A (fr) * | 1963-12-13 | 1965-01-29 | Thomson Houston Comp Francaise | Perfectionnements aux antennes |
FR2488058A1 (fr) * | 1980-07-29 | 1982-02-05 | Thomson Csf | Source rayonnante bi-bande compacte fonctionnant dans le domaine des hyperfrequences |
FR2601460B1 (fr) * | 1986-07-10 | 1988-12-02 | Onera (Off Nat Aerospatiale) | Installation pour la detection et la localisation spatiale par mesure interferometrique, en temps reel et a grande distance, des decharges de foudre |
US4801942A (en) * | 1986-08-18 | 1989-01-31 | Airborne Research Associates, Inc. | Interferometeric lightning ranging system |
US4972195A (en) * | 1986-08-18 | 1990-11-20 | Airborne Research Associates | Interferometric lightning ranging system |
DE102008056729B3 (de) * | 2008-11-11 | 2010-05-12 | Kathrein-Werke Kg | RFID-Antennen-System |
US8138986B2 (en) * | 2008-12-10 | 2012-03-20 | Sensis Corporation | Dipole array with reflector and integrated electronics |
CN102095943B (zh) * | 2010-11-25 | 2013-04-24 | 中国气象科学研究院 | 雷电预警方法及装置 |
CN103235284A (zh) * | 2013-03-29 | 2013-08-07 | 中国气象科学研究院 | 一种多站闪电甚高频辐射源三维定位方法和系统 |
-
2017
- 2017-12-20 FR FR1762580A patent/FR3075390B1/fr active Active
-
2018
- 2018-12-20 US US16/955,987 patent/US20210072338A1/en not_active Abandoned
- 2018-12-20 WO PCT/FR2018/053482 patent/WO2019122763A1/fr unknown
- 2018-12-20 MA MA051313A patent/MA51313A/fr unknown
- 2018-12-20 CN CN201880089851.4A patent/CN111788490A/zh active Pending
- 2018-12-20 EP EP18839844.0A patent/EP3729111A1/fr not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
FR3075390A1 (fr) | 2019-06-21 |
MA51313A (fr) | 2021-03-31 |
FR3075390B1 (fr) | 2020-09-18 |
WO2019122763A1 (fr) | 2019-06-27 |
CN111788490A (zh) | 2020-10-16 |
US20210072338A1 (en) | 2021-03-11 |
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