EP4359819A1 - Procédé de radar à ouverture synthétique - Google Patents

Procédé de radar à ouverture synthétique

Info

Publication number
EP4359819A1
EP4359819A1 EP22734914.9A EP22734914A EP4359819A1 EP 4359819 A1 EP4359819 A1 EP 4359819A1 EP 22734914 A EP22734914 A EP 22734914A EP 4359819 A1 EP4359819 A1 EP 4359819A1
Authority
EP
European Patent Office
Prior art keywords
radar
pulse
pulse sequences
strip
earth
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.)
Pending
Application number
EP22734914.9A
Other languages
German (de)
English (en)
Inventor
Felipe Queiroz de Almeida
Marwan YOUNIS
Gerhard Krieger
Alberto Moreira
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deutsches Zentrum fuer Luft und Raumfahrt eV
Original Assignee
Deutsches Zentrum fuer Luft und Raumfahrt eV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Deutsches Zentrum fuer Luft und Raumfahrt eV filed Critical Deutsches Zentrum fuer Luft und Raumfahrt eV
Publication of EP4359819A1 publication Critical patent/EP4359819A1/fr
Pending legal-status Critical Current

Links

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
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904—SAR modes
    • G01S13/9054—Stripmap mode
    • 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
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/22—Systems for measuring distance only using transmission of interrupted, pulse modulated waves using irregular pulse repetition frequency
    • G01S13/227—Systems for measuring distance only using transmission of interrupted, pulse modulated waves using irregular pulse repetition frequency with repetitive trains of uniform pulse sequences, each sequence having a different pulse repetition frequency

Definitions

  • the invention relates to a synthetic aperture radar method for remote sensing of the earth's surface via a radar device and a corresponding synthetic aperture radar sy stem.
  • Synthetic aperture radar methods which are also referred to as SAR methods, enable remote sensing of the earth's surface by detecting radar pulses which are emitted by a radar device on a platform and, after reflection on the earth's surface, are received again by this radar device will.
  • the platform moves at a constant speed over the earth's surface in a so-called azimuth direction, strips with a width in the so-called range direction being detected from the earth's surface, which extend perpendicularly to the azimuth direction.
  • the concept of the earth's surface is to be understood broadly and, in addition to the surface of the earth, can also include the surface of another celestial body and in particular a planet.
  • SAR radar methods take advantage of the knowledge that due to the moving platform, the same areas of the earth’s surface are recorded from different radar sensor positions, which means that amplitude and phase information and finally a radar image (also referred to as SAR image) of the Earth's surface can be obtained.
  • a synthetic aperture is thus generated in the azimuth direction.
  • the problem with SAR systems is that the radar device used cannot receive any radar echoes when emitting corresponding radar pulses. This can lead to the formation of gaps in the detected strip, these gaps also being referred to below as blind ranges.
  • the pulse repetition interval of the radar pulses is chosen to be so large that the duration of the received radar echoes is shorter than the pulse repetition interval and consequently no radar echoes are received when a radar pulse is emitted.
  • the entire stripe to be recorded is divided into several substripes, which are illuminated cyclically and alternately by the radar device.
  • a suitable pulse repetition interval is selected for each of these sub-strips, so that the entire strip can be recorded without gaps from the combination of all sub-strips.
  • this method usually has a poorer resolution than the stripmap operating mode.
  • the method has the disadvantage that the illumination of the individual substrips is regularly interrupted, which leads to gaps in the Doppler spectrum of the detected radar echoes. This results in a varying intensity in the azimuth direction (so-called scalloping), so that the quality of the captured SAR images is reduced.
  • the so-called staggered SAR operating mode is used to avoid blind areas, in which the pulse repetition rate of the transmitted radar pulses is varied cyclically, whereby the blind areas change their position in the range direction and are thus interpolated via the gaps that occur can (ie over samples in the direction of flight).
  • this method has the disadvantage that there is an irregular scanning grid in the azimuth direction and consequently a higher pulse repetition frequency is required overall, which in turn leads to a higher data rate.
  • the object of the invention is to create a synthetic aperture radar method and a corresponding synthetic aperture radar system which enable the detection of a wide strip on the earth's surface and thereby avoid the disadvantages described above.
  • the earth's surface is detected via a radar device on a platform, the platform moving in an azimuth direction over the earth's surface.
  • the radar device is preferably located on a satellite.
  • the radar device is a combined transmission and reception device, which in transmission mode represents a transmission device for emitting radar pulses and in reception mode represents a receiving device for receiving radar echoes of the radar pulses reflected on the earth's surface from a strip of the earth's surface.
  • This stripe (English: swath) has a predetermined stripe width in a range direction perpendicular to the azimuth direction.
  • the radar pulses are transmitted by the transmitting device in a plurality of pulse sequences that are interleaved and in this sense overlap in time, with the radar pulses being transmitted repeatedly in each pulse sequence based on a pulse repetition interval with a fixed time length, with each pulse sequence of the multiple pulse sequences has a pulse repetition interval with a different time length than the time length of the pulse repetition intervals of the remaining pulse sequences of the multiple pulse sequences.
  • the radar echoes are received in a single receiving channel in azimuth or in several receiving channels of the receiving device with azimuth positions offset from one another (i.e. positions in the azimuth direction) in successive reception periods corresponding to the strip width.
  • the reception periods represent time windows in which the radar echo of a single radar pulse can be received over the entire stripe width of the stripe, so that the detection of the entire stripe is ensured.
  • the radar echoes from a respective pulse sequence (ie each pulse sequence) of the plurality of pulse sequences at predetermined range positions within the strip contain gaps that each belong to radar echoes that cannot be received due to the transmission of a radar pulse.
  • There are two types of gaps for a respective pulse sequence which are also referred to below as first gaps and second gaps.
  • a first gap is caused by the fact that a radar pulse of the same pulse sequence is being transmitted when the radar echo of the corresponding pulse sequence is received.
  • a second gap is caused by the fact that when the radar echo of a corresponding pulse sequence is received, a radar pulse of another pulse sequence is being transmitted.
  • the second gaps change their range position along the strip in the azimuth direction, whereas the first gaps are always at the same range position.
  • reception lobes preferably with maximum radiation intensity, are used at different elevation angles, the elevation angle describing the inclination relative to the plane which is spanned by the height direction (ie the normal on the earth's surface) and the azimuth direction.
  • the corresponding reception lobes can be formed in a manner known per se via digital beam formation in a time-variant manner.
  • the essential feature of the SAR method according to the invention consists in the suitable design of the multiple pulse sequences.
  • the time lengths of the pulse repetition intervals of the multiple pulse sequences and the time shift of the multiple pulse sequences relative to one another are defined in such a way that the gaps in the radar echoes from different pulse sequences within the strip in the range direction do not overlap over all successive reception periods. In other words, there is no overlap between gaps in different pulse sequences in the range direction in the temporal sequence of the reception periods under consideration.
  • the gaps in different pulse sequences are thus located at different, non-overlapping range positions (ie positions in the range direction).
  • the above feature ensures that the gaps in different pulse sequences are always at different range positions, so that for each range position there is always a series of radar echoes (over the flight direction) without gaps and the strip is therefore full width can be detected.
  • the disadvantages of known SAR operating modes are avoided.
  • the scalloping effect mentioned above does not occur since the entire strip is continuously illuminated as in the conventional SAR stripmap mode.
  • Another advantage compared to the ScanSAR mode is the possibility to achieve a finer azimuth resolution.
  • no azimuth interpolation filter is required due to the regular sampling in the respective pulse sequences, whereby the Data processing is significantly simplified.
  • on-board processing on the platform of the radar device can be dispensed with, so that the instruments carried on the platform can be significantly simplified.
  • the time lengths of the pulse repetition intervals of the plurality of pulse sequences and their time shift relative to one another are also defined in such a way that at each end of the two ends of the strip in the range direction there is a gap in the radar echoes of each pulse sequence of the plurality Pulse sequences adjacent and it is outside the strip, the gap belongs to radar echoes of the respective pulse sequence that cannot be received due to the transmission of a radar pulse in the respective pulse sequence.
  • the gap is thus a first gap.
  • the greatest possible pulse repetition frequency is selected for a given stripe width and corresponding echo duration. As a result, high pulse repetition frequencies and thus small pulse repetition intervals are achieved, which ensures very good azimuth resolution.
  • the multiple pulse sequences contain exactly two pulse sequences, which greatly simplifies the method.
  • the following conditions preferably apply to the two pulse sequences:
  • N 1 PRl 1 N 2 PRI 2
  • PRl 1 is the pulse repetition interval of one of the two pulse sequences
  • PRI 2 is the pulse repetition interval of the other of the two pulse sequences
  • N 1 and N 2 are positive integers that are relatively prime. That is, there is no natural number other than 1 that divides N 1 and N 2 .
  • the conditions according to the invention for the gaps can be implemented particularly easily. This ensures that the time offsets that occur between adjacent radar pulses of different pulse sequences are repeated. Furthermore, the sequence length of this repetition can be kept small.
  • the shifting of the two pulse sequences with respect to one another is defined in such a way that the minimum offset that is not equal to zero, which occurs between two temporally adjacent pulses of different pulse sequences, is maximized.
  • These maximized offsets can easily be determined by a person skilled in the art given appropriately defined values for N 1 and N 2 .
  • This variant of the invention has the advantage that range ambiguities of the radar echoes are further apart, as a result of which they are better suppressed and better image quality results.
  • M ch max ⁇ N 1 . m; . 2 ⁇ m) where L az is the length of the receiving device in the azimuth direction; where M ch is the number of receiving channels; where v sat is the speed of the platform in azimuth over the surface of the earth; and where m is a positive integer.
  • an equidistant scanning in the azimuth direction can be achieved when using several receiving channels and a transmitting device with a single transmitting channel (i.e. a single fixed phase center).
  • the transmission device emits radar pulses for a respective pulse sequence of at least part of the plurality of pulse sequences and preferably for each pulse sequence of the plurality of pulse sequences, which only illuminate those sections of the strip in which there are no gaps in the respective pulse sequence. In this way, the transmission power of the transmission device can be suitably reduced.
  • the transmission device emits radar pulses for one pulse sequence, which illuminate the entire strip, whereas the transmission device emits radar pulses for each other pulse sequence, which only illuminate those sections of the strip in which there are no gaps in the respective other Pulse sequence, but there are gaps in one pulse sequence.
  • SAR images of the earth's surface are determined separately from the radar echoes of each pulse sequence of the plurality of pulse sequences, ie a stripmap processing known per se is carried out separately for each pulse sequence.
  • a joint SAR image is then calculated from these SAR images.
  • this SAR image does not contain any blind areas.
  • the S AR images are preferably not determined or calculated on the platform that is moved over the surface of the earth. Rather, the SAR data are first transmitted to a ground station on Earth, where the processing to determine the SAR images is then carried out.
  • the invention relates to a synthetic aperture radar system with a radar device on a platform that moves (when the radar system is in operation) in an azimuth direction above the earth's surface.
  • the radar device is a combined transmitting and receiving device which, in transmitting mode, represents a transmitting device for emitting radar pulses and, in receiving mode, represents a receiving device for receiving radar echoes of the radar pulses reflected on the earth's surface from a strip on the earth's surface.
  • the stripe has a predetermined stripe width in a range direction perpendicular to the azimuth direction.
  • the synthetic aperture radar system or its radar device is designed in such a way that the method according to the invention or one or more preferred variants of the method according to the invention can be carried out with it.
  • FIG. 1 shows a schematic representation of a SAR system to illustrate the formation of gaps in the radar echoes
  • FIG. 2 shows a schematic representation of two interleaved pulse sequences of radar pulses which are used in an embodiment of the method according to the invention
  • FIG. 5 shows a schematic representation of the other pulse sequence from FIG. 2 to clarify the formation of blind areas in the radar echoes of this pulse sequence
  • FIG. 6 shows a schematic illustration which once again reproduces the blind areas in the radar echoes of both pulse sequences from FIG. 2;
  • FIG. 7 shows a schematic representation which illustrates two variants of radiation lobes for radar pulses emitted in the method according to the invention.
  • a corresponding satellite 1 shows an example of a corresponding satellite 1, which includes a radar device 2 in the form of a combined transmission and reception device for corresponding radar pulses.
  • This radar device 2 is operated in transmission mode to emit the radar pulses and then represents a transmission device which is denoted by reference numeral 2a in FIG.
  • the radar echoes reflected by the radar pulses on the earth's surface S are detected in the reception mode of the radar device 2, so that the radar device in the reception mode represents a corresponding receiving device, which is denoted by reference numeral 2b in FIG.
  • the satellite 1 moves together with the radar device 2 in the so-called azimuth direction over the earth's surface S.
  • This direction of movement corresponds to the x-direction in the coordinate system shown in FIG.
  • the radar pulses are sent obliquely onto the earth's surface S.
  • the y-direction of the coordinate system shown in FIG. 1 represents the range direction, which is perpendicular to the direction of movement of satellite 1 runs.
  • the range direction correlates with corresponding oblique distances R, which represent distances between the radar device 2 and corresponding points on the earth's surface.
  • the earth's surface is to be recorded in a strip SW, which extends along the azimuth direction and has a predefined width B in the range direction.
  • the ends of the strip SW in the range direction are represented by the distances R min and R max .
  • Corresponding SAR images of the earth's surface can be determined using SAR processing, which is known per se, by detecting radar echoes from this strip.
  • the principle of SAR processing is based on the fact that respective points on the earth's surface are recorded multiple times from different perspectives due to the movement of satellite 1 . Due to the Doppler effect, there is a frequency shift when recording the radar echoes, which can be suitably evaluated, whereby amplitude and phase information of the radar pulses reflected on the surface can be obtained and corresponding image information can be obtained as a result.
  • HRWS High-Resolution Wide-Swath
  • the radar pulses transmitted in this operating mode are denoted by RP in FIG. 1 and are transmitted repeatedly based on a fixed pulse repetition interval PRI.
  • the radar echoes EC are to be evaluated which arrive in the radar device 2 in the time period 2/cR min to 2/cR max and correspond to the width B of the strip SW.
  • SAR operating modes can also provide information on the blind areas described above. This means that the SAR images can be obtained over the entire width B.
  • bursts consisting of a large number of radar pulses with different pulse repetition rates are transmitted one after the other. The bursts each illuminate different partial strips of the strip SW to be detected. Since the position of the blind areas differs between the bursts, information can be obtained from all areas of the strip.
  • the ScanSAR operating mode leads to poor azimuth resolution and requires complex processing.
  • the staggered SAR operating mode in which the pulse repetition interval of the transmitted radar pulses is rapidly varied cyclically, which leads to a continuous change in the position of the blind areas, so that interpolation in the azimuth direction is also possible Information can be obtained from corresponding blind areas.
  • the disadvantage here is the irregular scanning in the azimuth direction due to the variation in the pulse repetition intervals.
  • a higher average pulse repetition rate is required, because successful interpolation requires a certain correlation or redundancy between the sampled values in the flight direction.
  • the higher mean pulse repetition rate in turn leads to a high data rate.
  • the pulse repetition rate is constant for each pulse sequence.
  • the pulse repetition rates and the shifting of the pulse sequences are selected in such a way that over all successive reception periods of the corresponding radar echoes, the blind areas of the radar echoes from one pulse sequence are always at a different point in the range direction than the blind areas of the other pulse sequence.
  • FIG. 2 shows, by way of example, a variant of two interleaved pulse sequences which are used in the embodiment of the method according to the invention described here.
  • the radar pulses transmitted along the time axis t are represented by bars.
  • the white bars represent radar pulses RP1, which belong to a first pulse sequence SE1 and are transmitted with the constant pulse repetition interval PR11 .
  • the hatched bars represent radar pulses RP2 of a second pulse sequence SE2, which has a smaller pulse repetition interval PRI 2 .
  • the pulses of both sequences have the identical pulse length ⁇ p .
  • the earliest pulse RP1 in time of the first pulse sequence SE1 is offset by ⁇ p compared to the adjacent pulse RP2 of the second pulse sequence SE2.
  • the radar pulses RP1 of the first pulse sequence are indicated by white bars and the radar pulses RP2 of the second radar pulses are indicated by hatched bars
  • N 1 PRl 1 N 2 PRI 2 , where N 1 and N 2 represent positive integers which are relatively prime.
  • ⁇ guard is a guard interval that is significantly smaller than ⁇ p and can also be set to zero if necessary.
  • blind areas arise for the first sequence SE1 centered on the distances and for the second sequence
  • gaps or blind The areas are also referred to below as co-gaps and correspond to the first gaps within the meaning of the patent claims. They are caused by the transmission of a radar pulse in the same pulse sequence as the received radar echo (transmission times t 1 [m]). In the case of several pulse sequences, there are further gaps or blind areas, which are referred to below as cross gaps and correspond to the second gaps within the meaning of the patent claims. These are caused by the fact that when a radar pulse from one sequence is received, a radar pulse from the other sequence is being transmitted (transmission times t 2 [m′]). In contrast to the Co gaps, the distances of these cross gaps are denoted by R 12 and R 21 in the following.
  • R 12 refers to a cross gap for a received radar echo of the first sequence, which was caused by the transmission of a radar pulse of the second sequence.
  • R 21 relates to a cross gap in the received radar echo of the second sequence, which is caused by the transmission of a radar pulse from the first sequence.
  • the co-gaps and cross-gaps for corresponding radar echoes of the first sequence are at the following positions, the distances always starting from the edge R min of the detected strip SW minus that with the Pulse length ⁇ p corresponding distance value can be measured: (proportional to t 1 [n 0 + n] — t 1 [n 0 ])
  • R min ⁇ R 11 (n +n 0 ) ⁇ R max . n 0 designates the number of so-called “travelling pulses” that are transmitted until the echo of a radar pulse that comes from the beginning of the strip SW at position
  • R min originates, is received in the radar device. Ie, it applies
  • the above condition means that all relevant Co-gaps are those that lie within the detected swath SW.
  • the cross gaps change due to the different pulse repetition intervals PRI 1 and PRI 2 Range position along the corresponding strip SW in azimuth direction, whereas the Co gaps keep their position.
  • the cross gaps for the second sequence are also centered at the following distances:
  • indices k′, m′ are relevant for which the following applies: 2 R min ⁇ R 11 (k′+m′) ⁇ R max .
  • the criterion according to the invention according to which co-gaps and cross-gaps of different pulse sequences are always at different range positions within the strip SW, is met for the pulse sequences illustrated in FIGS will be explained with reference to FIG. In the following it is specified how the criterion according to the invention can be described in general terms, with two pulse sequences being assumed without loss of generality and the variables described above also being used.
  • N 1 and N 2 are positive integers that are relatively prime, ie there is no natural number other than 1 that divides both N 1 and N 2 .
  • PR11 , N1 and N2 can be adapted as a function of the ends of the strips, ie as a function of Rmin and Rmax , such that the radar echo of the strip is received precisely between N1Co gaps .
  • FIG. 6 again clarifies the position of the Co gaps and Cross gaps in the corresponding pulse sequences SE1 and SE2 according to the embodiment from FIGS. 2 to 5.
  • the icon PI2 of FIG. 6 shows the co-gaps and cross-gaps for the second pulse sequence SE2.
  • the co-gaps are denoted there by BR1' and the cross-gaps by BR2'.
  • the co-gaps are now shown as hatched bars, while the cross-gaps are white bars.
  • only some of the gaps are provided with the corresponding reference symbols BR1' or BR2'.
  • the range positions of the cross gaps also vary in the azimuth direction for the second pulse sequence. In contrast to the first pulse sequence, the same pulse pattern now occurs again after every third radar pulse, which is indicated by the arrow P2.
  • the method described above is not limited to using a single azimuth channel.
  • the radar pulses can also be received via several azimuth channels, i.e. simultaneously at different receiving positions in the azimuth direction.
  • an advantageous equidistant sampling of the SAR signals can also be achieved.
  • the radar pulses are always transmitted with the same reception lobe, which covers the entire strip to be detected.
  • this is not absolutely necessary. Rather, it is also possible for the radar pulses of the first sequence to detect strips other than the radar pulses of the second sequence, with the radar pulses of at least one sequence and possibly each sequence detecting only those sections of the strip in which there are no co-gaps or cross-gaps of the corresponding sequence, provided that SAR data are still obtained for the entire strip width.
  • FIG. 7 illustrates two embodiments of the invention based on the two pulse sequences SE1 and SE2 described above.
  • the blind BR1 and BR2 for the first pulse sequence SE1 in the detected strip SW are reproduced in the pictogram PI1' of FIG. 7, the entire strip being detected with the transmission lobe TI of the transmission device.
  • the blind areas for the second pulse sequence SE2 are shown in pictogram PI2', with a variant being shown in which the entire strip is covered with the radiation lobe T2 of the transmitting device.
  • areas from the strip are also shown by hatched sections A, in which the blind areas of the first pulse sequence are located. Only for these hatched sections is there no data on radar echoes in the first pulse sequence.
  • the transmission lobe for the second pulse sequence can be adjusted in such a way that it only covers the hatched sections A. This is reflected in the pictogram PI3'. As can be seen there, the transmission device emits radar pulses for the second pulse sequence in three separate partial transmission lobes T2' only toward the hatched sections A. This has the advantage that less transmission power is required to transmit the radar pulses.
  • a SAR method is created with which a strip with a large width and high azimuth resolution can be detected while avoiding the disadvantages of conventional operating modes.
  • the use of fixed pulse repetition rates ensures regular sampling in azimuth, eliminating the need for azimuth interpolation filters as is the case in the traditional staggered SAR mode of operation.
  • Conventional stripmap processing can thus be used to process the detected radar echoes.
  • the method also enables a pulse repetition frequency that is lower in comparison to the staggered SAR operating mode, as a result of which the data rate is reduced and distance ambiguities are positively influenced.
  • azimuth performance advantages can be achieved over both the Staggered SAR mode of operation and the ScanSAR mode of operation.
  • the method of the invention was tested by the inventors within the framework of simulations. Indeed, it has been found that the advantages outlined above can be achieved over conventional modes of operation.

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

Abstract

L'invention se rapporte à un procédé de radar à ouverture synthétique pour la détection à distance de la surface terrestre au moyen d'un dispositif radar (2) sur une plateforme (1) qui se déplace dans une direction azimutale (x) au-dessus de la surface terrestre (S), le dispositif radar (2) constituant un dispositif émetteur et récepteur combiné qui représente un dispositif émetteur (2a) permettant d'émettre des impulsions radar (RP1, RP2) pendant une opération d'émission et représente un dispositif récepteur (2b) permettant de recevoir des échos (EC) radar des impulsions radar (RP1, RP2) réfléchies au niveau de la surface terrestre depuis une bande (SW) sur la surface terrestre (S) pendant l'opération de réception. Les impulsions radar (RP1, RP2) sont émises par le dispositif émetteur (2a) dans une pluralité de séquences d'impulsions entrelacées (SE1, SE2) avec des intervalles de répétition d'impulsions (PRI1, PRI2) de longueurs différentes. Les échos radar (EC) sont reçus dans des périodes de réception successives, les durées des intervalles de répétition d'impulsions (PRI1, PRI2) de la pluralité de séquences d'impulsions (SE1, SE2) et leur décalage temporel les unes par rapport aux autres étant définis de telle sorte que, sur toutes les périodes de réception successives, des intervalles correspondants (BR1, BR1', BR2, BR2') des échos radar (EC) provenant de différentes séquences d'impulsions (SE1, SE2) à l'intérieur de la bande (SW) ne se chevauchent pas dans la direction de visée (y).
EP22734914.9A 2021-06-24 2022-06-15 Procédé de radar à ouverture synthétique Pending EP4359819A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102021206555.4A DE102021206555A1 (de) 2021-06-24 2021-06-24 Synthetik-Apertur-Radarverfahren
PCT/EP2022/066303 WO2022268600A1 (fr) 2021-06-24 2022-06-15 Procédé de radar à ouverture synthétique

Publications (1)

Publication Number Publication Date
EP4359819A1 true EP4359819A1 (fr) 2024-05-01

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Application Number Title Priority Date Filing Date
EP22734914.9A Pending EP4359819A1 (fr) 2021-06-24 2022-06-15 Procédé de radar à ouverture synthétique

Country Status (3)

Country Link
EP (1) EP4359819A1 (fr)
DE (1) DE102021206555A1 (fr)
WO (1) WO2022268600A1 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2412852A1 (fr) * 1977-12-22 1979-07-20 Labo Cent Telecommunicat Perfectionnements aux radars doppler a impulsions
DE102019106858B3 (de) 2019-03-18 2020-06-25 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zum Rekonstruieren einer fehlenden Abtastung eines korrelierten Signals in einem SAR-System

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WO2022268600A1 (fr) 2022-12-29

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