CN106950566A - A kind of synthetic aperture radar image-forming method and device - Google Patents
A kind of synthetic aperture radar image-forming method and device Download PDFInfo
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- CN106950566A CN106950566A CN201710091131.9A CN201710091131A CN106950566A CN 106950566 A CN106950566 A CN 106950566A CN 201710091131 A CN201710091131 A CN 201710091131A CN 106950566 A CN106950566 A CN 106950566A
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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
- 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
- G01S13/9004—SAR image acquisition techniques
- G01S13/9017—SAR image acquisition techniques with time domain processing of the SAR signals in azimuth
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Abstract
The invention discloses a kind of synthetic aperture radar image-forming method and device, wherein, methods described includes：Determine the first angular speed and imaging time of the SAR；Wherein, first angular speed is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging；Second angular speed is determined according to the maximum angular velocity of rotation of the machinery of the SAR；Wherein, second angular speed is the angular speed that the SAR carries out mechanical scanning；The third angle speed is determined according to first angular speed and second angular speed, wherein, the third angle speed is the angular speed that the SAR carries out electric scanning；Control the SAR to carry out mechanical scanning and electric scanning according to second angular speed, the third angle speed and imaging time, obtain echo data；Line slip spotlight imaging is entered according to the echo data.
Description
Technical field
The present invention relates to Radar Technology field, more particularly to a kind of synthetic aperture radar image-forming method and device.
Background technology
Synthetic aperture radar (Synthetic Aperture Radar, SAR) satellite is that SAR is carried on satellite, is entered
Row earth observation, due to using microwave Imaging Technique, can be achieved round-the-clock, round-the-clock observation, is important earth observation means.
A kind of imaging pattern that pack is SAR satellites is slided, the pattern utilizes Azimuth beam forward scan, slows down wave beam
Footmark ground moving speed, realizes high-resolution imaging.Slide beam bunching mode azimuth resolution, mainly from antenna bearingt to
The sweep speed and maximum scan angle of wave beam are determined.
Azimuth beam scanning has two kinds of possible implementations, respectively electric scanning and mechanical scanning.The two can be real
Existing Azimuth beam scan operation, but they the characteristics of it is different.
Electric scanning is typically by Planar Phased Array Antenna or the paraboloidal-reflector antenna with feeding network is realized.Fig. 1-1
The schematic diagram for sliding spotlight imaging is realized for antenna beam electric scanning.As Figure 1-1, at t1, t2, t3 moment, SAR satellites
Attitude does not change.Antenna beam electric scanning is obtained by controlling the signal phase and amplitude of different array-element antennas
Required antenna radiation pattern, so as to the quick sensing for changing antenna beam and shape, realizes that Azimuth beam is scanned.Electricity is swept
The characteristics of mode of retouching has flexible, quick, but when beam position is away from antenna normal direction, electric scanning mode can produce graing lobe increasing
The pattern distortions such as benefit rising, beam-broadening and main lobe gain decline, deteriorate the performance indications of system.Although passing through increase
Permutation antenna element number can significantly weaken, even completely eliminate disadvantages mentioned above, but substantial amounts of antenna element can make whole SAR
Weight, complexity and the cost of antenna system steeply rise.
Fig. 1-2 is that slip pack schematic diagram is realized in antenna beam mechanical scanning.As shown in Figure 1-2, at t1, t2, t3 moment
The attitude angle of SAR satellites is changing.Mechanical scanning controls the attitude angle of satellite platform by attitude control system, makes fixation
Radar antenna beam position consecutive variations on platform；Either transported by the machinery of the direct control radar antenna of dynamical system
It is dynamic, make its beam position consecutive variations, realize that orientation is scanned.Mechanical scanning mode motional inertia is big, and sweep speed is not high,
It is difficult to realize adjustment beam scanning speed in real time, it is impossible to realize the quick sensing saltus step of wave beam, but this mode is not in grid
Valve effect and beam-broadening effect.
Most of SAR satellites in-orbit at present realize slip spotlight imaging, but its point using antenna beam electric scanning mode
The raising of resolution is limited by antenna electric scanning maximum angle.Only have indivedual grapefruit satellites at present, such as TecSAR satellites are adopted
Realized with satellite platform rotating manner and slide spotlight imaging.For commonplace medium-sized, Large-scale satellite, due to rotary inertia too
Greatly, mechanical scanning speed is low, is difficult to slide spotlight imaging using which.
The content of the invention
For solve prior art present in technical problem, the embodiment of the present invention can provide a kind of synthetic aperture radar into
As method and device, it is possible to increase antenna beam azimuths of the SAR under spotlight imaging pattern is to sweep speed and scans maximum angular
Degree, so as to lift the azimuth resolution of SAR image.
To reach above-mentioned purpose, what the technical scheme of the embodiment of the present invention was realized in：
In a first aspect, the embodiment of the present invention provides a kind of synthetic aperture radar image-forming method, methods described includes：
Determine the first angular speed and imaging time of the SAR；Wherein, first angular speed is that the SAR is slided
The angular speed of Azimuth beam scanning during dynamic spotlight imaging；
Second angular speed is determined according to the maximum angular velocity of rotation of the machinery of the SAR；Wherein, second angular speed is institute
State the angular speed that SAR carries out mechanical scanning；
The third angle speed is determined according to first angular speed and second angular speed, wherein, the third angle speed
It is the angular speed that the SAR carries out electric scanning；
The SAR progress mechanical scannings and electricity is controlled to sweep according to second angular speed, the third angle speed and imaging time
Retouch, obtain echo data；
Line slip spotlight imaging is entered according to the echo data.
Second aspect, the embodiment of the present invention provides a kind of synthetic aperture radar image-forming device, and described device includes：
First determining module, the first angular speed and imaging time for determining the SAR；Wherein, first jiao of speed
Degree is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging；
Second determining module, the second angular speed is determined for the maximum angular velocity of rotation of machinery according to the SAR；Wherein,
Second angular speed is the angular speed that the SAR carries out mechanical scanning；
3rd determining module, for determining the third angle speed according to first angular speed and second angular speed, its
In, the third angle speed is the angular speed that the SAR carries out electric scanning；
Control module, for controlling the SAR to carry out machine according to second angular speed, the third angle speed and imaging time
Tool is scanned and electric scanning, obtains echo data；
Image-forming module, for entering line slip spotlight imaging according to the echo data.
The embodiment of the present invention provides a kind of synthetic aperture radar image-forming method and device, wherein, it is first determined the SAR's
First angular speed and imaging time；Wherein, first angular speed is Azimuth beam when the SAR enters line slip spotlight imaging
The angular speed of scanning；The second angular speed is determined further according to the maximum angular velocity of rotation of machinery of the SAR；Wherein, described second jiao
Speed is the angular speed that the SAR carries out mechanical scanning；Then determined according to first angular speed and second angular speed
The third angle speed, wherein, the third angle speed is the angular speed that the SAR carries out electric scanning；According to second angular speed,
The third angle speed and imaging time control the SAR to carry out mechanical scanning and electric scanning, obtain echo data；Finally according to described
Echo data enters line slip spotlight imaging.Thus, when synthetic aperture radar carries out the imaging under beam bunching mode, combining electricity and sweeping
The advantage with mechanical scanning is retouched, antenna beam azimuth is improved to sweep speed and scanning maximum angle, so as to lift SAR image
Azimuth resolution.
Brief description of the drawings
Fig. 1-1 is that the schematic diagram for sliding spotlight imaging is realized in antenna beam electric scanning；
Fig. 1-2 is that slip pack schematic diagram is realized in antenna beam mechanical scanning；
Fig. 2 realizes schematic flow sheet for the synthetic aperture radar image-forming method of the embodiment of the present invention one；
Fig. 3 realizes schematic flow sheet for the synthetic aperture radar image-forming method of the embodiment of the present invention two；
Fig. 4-1 is that the SAR satellites of the embodiment of the present invention three constitute structure and the normal in-orbit state of flight schematic diagram of SAR satellites；
Fig. 4-2 is the synthetic aperture radar image-forming geometrical relationship schematic diagram of the embodiment of the present invention three；
Fig. 4-3 realizes schematic flow sheet for the synthetic aperture radar image-forming method of the embodiment of the present invention three；
Fig. 5 is the composition structural representation of the synthetic aperture radar image-forming device of the embodiment of the present invention four；
Fig. 6 is the composition structural representation of the synthetic aperture radar image-forming device of the embodiment of the present invention five.
Embodiment
To make the purpose, technical scheme and advantage of the embodiment of the present invention clearer, below in conjunction with the embodiment of the present invention
In accompanying drawing, the concrete technical scheme to invention is described in further detail.Following examples are used to illustrate the present invention, but without
To limit the scope of the present invention.
Embodiment one
The embodiment of the present invention provides a kind of synthetic aperture radar image-forming method, applied to synthetic aperture radar image-forming device,
Fig. 2 realizes schematic flow sheet for the synthetic aperture radar image-forming method of the embodiment of the present invention one, as shown in Fig. 2 methods described bag
Include following steps：
Step S201, determines the first angular speed and imaging time of the SAR.
Here, first angular speed is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging.
The step S201 further comprises：
Step S201a, gathers the systematic parameter of the SAR；
Here, the systematic parameter of the SAR include but is not limited to be：The speed of service of the SAR, oblique distance, antenna are equivalent
Orientation length and Azimuth beam width.
Step S201b, obtains imaging region orientation length set in advance and azimuth resolution；
Here, the imaging region orientation length and azimuth resolution can be that staff enters according to actual needs
Row setting.
Step S201c, according to being determined the systematic parameter, imaging region orientation length and azimuth resolution
SAR the first angular speed and imaging time.
Step S202, the second angular speed is determined according to the maximum angular velocity of rotation of the machinery of the SAR.
Here, second angular speed is the angular speed that the SAR carries out mechanical scanning.In actual implementation process,
The maximum angular velocity of rotation of the mechanical scanning of the SAR can be defined as second angular speed or to the SAR's
Mechanical scanning maximum angular velocity of rotation carries out certain computing to determine the second angular speed, than the mechanical scanning of SAR as will be described
Maximum angular velocity of rotation subtracts one and is worth to second angular speed.
Step S203, the third angle speed is determined according to first angular speed and second angular speed.
Here, the third angle speed is the angular speed that the SAR carries out electric scanning.In actual implementation process, press
The third angle speed is determined according to formula (1-1).
ωb=ω-ωs(1-1)；
Wherein, ω is the first angular speed, ωsFor the second angular speed, ωbFor the third angle speed.
Step S204, controls the SAR to carry out machinery and sweeps according to second angular speed, the third angle speed and imaging time
Retouch and electric scanning, obtain echo data；
Here, it is described to control the SAR progress machinery to sweep according to second angular speed, the third angle speed and imaging time
Retouch and further comprise with electric scanning：
The mechanical scanning of a length of imaging time when controlling the SAR to be carried out according to second angular speed；
Here, when controlling the SAR to be carried out according to second angular speed a length of imaging time mechanical scanning
Before, the first pitching of the SAR can be controlled to the first predetermined angle in advance, first predetermined angle is a larger angle,
Then the SAR is controlled to start rotation, and through after a period of time, the angle of pitch of the SAR is the second predetermined angle, and is reached
Second angular speed is simultaneously kept.
The electric scanning of a length of imaging time when controlling the SAR to be carried out according to the third angle speed；Wherein, it is described
Being spaced in default time range between at the beginning of mechanical scanning and at the beginning of the electric scanning.
In embodiments of the present invention, when the SAR enters line slip pack, the mechanical scanning and electric scanning of antenna beam are same
Shi Jinhang's, therefore the actual beam scanning formed on ground, it is the stack result of mechanical scanning and electric scanning, so improves
Antenna beam azimuth is to angular scanning speed and scanning maximum angle, so as to lift the azimuth resolution of SAR image.
Step S205, line slip spotlight imaging is entered according to the echo data.
Here, line slip spotlight imaging is entered according to the echo data, can be, but not limited to be to utilize range Doppler
(Range-Doppler, RD) algorithm, linear frequency modulation change of scale (Chirp-Scaling, CS) algorithm, extension CS (Extended
Chirp Scaling ECS) algorithm realization.
The embodiment of the present invention provides a kind of synthetic aperture radar image-forming method, wherein, it is first determined first jiao of the SAR
Speed and imaging time；Wherein, first angular speed is that Azimuth beam is scanned when the SAR enters line slip spotlight imaging
Angular speed；The second angular speed is determined further according to the maximum angular velocity of rotation of machinery of the SAR；Wherein, second angular speed is
The SAR carries out the angular speed of mechanical scanning；Then the third angle is determined according to first angular speed and second angular speed
Speed, wherein, the third angle speed is the angular speed that the SAR carries out electric scanning；According to second angular speed, the third angle
Speed and imaging time control the SAR to carry out mechanical scanning and electric scanning, obtain echo data；Finally according to the number of echoes
According to entering line slip spotlight imaging.Thus, when synthetic aperture radar carries out the imaging under beam bunching mode, combining electric scanning and machine
The advantage of tool scanning, improves antenna beam azimuth to sweep speed and scanning maximum angle, so as to lift the orientation of SAR image
Resolution ratio.
Embodiment two
Based on foregoing embodiment, the embodiment of the present invention provides a kind of synthetic aperture radar image-forming method again, applied to conjunction
Into aperture radar imaging device, the synthetic aperture radar image-forming device can be processor in actual implementation process.Fig. 3 is
The embodiment of the present invention two synthetic aperture radar image-forming method realizes schematic flow sheet, as shown in figure 3, methods described include it is following
Step：
Step S301, determines the first angular speed and imaging time of the SAR.
Here, first angular speed is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging.
The step S301, further comprises：
Step S301a, gathers the systematic parameter of the SAR；
Here, the systematic parameter of the SAR include but is not limited to be：The speed of service of the SAR, oblique distance, antenna are equivalent
Orientation length and Azimuth beam width.
Step S301b, obtains imaging region orientation length set in advance and azimuth resolution；
Here, the imaging region orientation length and azimuth resolution can be that staff enters according to actual needs
Row setting.
Step S301c, according to being determined the systematic parameter, imaging region orientation length and azimuth resolution
SAR the first angular speed and imaging time.
Here, the step S301c further comprises：
The first step, according to formula (2-1), determine pivot oblique distance Rrot；
Wherein, ρ is azimuth resolution, R0For the most short oblique distance of range Imaging scene, DaIt is long for the equivalent orientation of antenna
Degree.
Here, formula (2-2) is obtained according to formula (2-1)；
Second step, according to formula (2-3) and (2-4), determine that the SAR enters the scanning angle of line slip spotlight imaging
θsteer；
Here, formula (2-5) is obtained according to formula (2-2) and formula (2-4)；
Formula (2-5) is updated to formula (2-3), formula (2-6) is obtained；
Formula (2-6) is subjected to triangulate decomposition method, formula (2-7) is obtained；
Wherein,
Formula (2-8) is obtained by formula (2-7)；
3rd step, according to formula (2-9) determine the imaging time Ta；
4th step, according to formula (2-10) determine first angular velocity omega.
Step S302, the second angular speed is determined according to the maximum angular velocity of rotation of the machinery of the SAR.
Here, second angular speed is the angular speed that the SAR carries out mechanical scanning.In actual implementation process,
The maximum angular velocity of rotation of the mechanical scanning of the SAR can be defined as second angular speed or to the SAR's
Mechanical scanning maximum angular velocity of rotation carries out certain computing to determine the second angular speed, than the mechanical scanning of SAR as will be described
Maximum angular velocity of rotation subtracts one and is worth to second angular speed.
Step S303, the third angle speed is determined according to first angular speed and second angular speed.
Here, the third angle speed is the angular speed that the SAR carries out electric scanning.In actual implementation process, press
The third angle speed is determined according to formula (1-1).
For conventional SAR satellites, the maximum angular velocity of rotation of SAR mechanical scanning is typically defined as the second angular speed,
The mechanical scan capability of satellite can be so maximally utilized, so as to reduce electric scanning angular speed, and then electric scanning maximum angular is reduced
Degree, can so reduce antenna bearingt to electric scanning graing lobe, be conducive to improving picture quality.
Step S304, determines that the SAR carries out the maximum scan angle of electric scanning.
Step S305, judges whether the product of second angular speed and the imaging time is not more than the electric scanning
Maximum scan angle；
Here, if the product of second angular speed and the imaging time is not more than the maximum scan of the electric scanning
Angle then enters step S306；If the product of second angular speed and the imaging time is more than the maximum of the electric scanning
Scanning angle, then into step S308.
Step S306, controls the SAR to carry out machinery and sweeps according to second angular speed, the third angle speed and imaging time
Retouch and electric scanning, obtain echo data.
Step S307, line slip spotlight imaging is entered according to the echo data.
Step S308, points out to reset imaging region orientation length and azimuth resolution.
Here, if the product of second angular speed and the imaging time is more than the maximum scan angle of the electric scanning
Degree, then show that if carrying out electric scanning based on second angular speed graing lobe gain rising, beam-broadening and main lobe can be produced
The pattern distortions such as gain decline, deteriorate the performance indications of system.Now need to reset imaging region orientation length
And azimuth resolution.
The embodiment of the present invention provides a kind of synthetic aperture radar image-forming method, wherein, it is first determined first jiao of the SAR
Speed and imaging time；Wherein, first angular speed is that Azimuth beam is scanned when the SAR enters line slip spotlight imaging
Angular speed；The second angular speed is determined further according to the maximum angular velocity of rotation of machinery of the SAR；Wherein, second angular speed is
The SAR carries out the angular speed of mechanical scanning；Then the third angle is determined according to first angular speed and second angular speed
Speed, wherein, the third angle speed is the angular speed that the SAR carries out electric scanning；According to second angular speed, the third angle
Speed and imaging time control the SAR to carry out mechanical scanning and electric scanning, obtain echo data；It is last in the third angle speed and
Line slip spotlight imaging is entered according to the echo data when product of imaging time meets certain condition.Thus, in synthetic aperture
When radar carries out the imaging under beam bunching mode, the advantage of electric scanning and mechanical scanning is combined, improve antenna beam azimuth to sweeping
Speed and scanning maximum angle are retouched, so as to lift the azimuth resolution of SAR image.
Embodiment three
In order to more fully understand the present embodiment, the composition structure of SAR satellites is first introduced.Fig. 4-1 is implemented for the present invention
The SAR satellites of example three constitute the normal in-orbit state of flight schematic diagram of structure and SAR satellites, as shown in Fig. 4-1, SAR satellites it is main by
Satellite body 501 and the two parts of antenna 502 composition.Under normal in-orbit state of flight, the definition of SAR satellite body coordinate systems is：
The origin of coordinates is located at centroid of satellite O；X-axis points to satellite flight direction, with antenna bearingt to consistent；Z axis along antenna array normal direction,
And refer to earthwards；Y-axis is vertical with X, Z axis, meets right-hand rule.OE is pointed to the angle in the earth's core, OE and OZ by satellite in figure
For the lateral swinging angle of SAR satellites.
In order to combine electric scanning and mechanical scanning, while satellite antenna carries out electric scanning, satellite need to be carried out around Y-axis
Rotation, specific implementation is as shown in the Fig. 4-2.
As shown in the Fig. 4-2, satellite is with speed VsFlight, the most short oblique distance of scape of leaving the theatre is R0.Start before imaging, satellite is first bowed
Face upward to larger angle, start elapsed time T after rotationp, reach angular velocity omegasAnd keep, now the satellite angle of pitch is θstart,s。
Start to slide spotlight imaging, antenna beam electric scanning angle is θstart,b, angular scanning speed is ωb, elapsed time Ta, terminate imaging.
Satellite mechanical scanning and the initial sweep angle θ of antenna electric scanning synthesisstartObtained by formula (3-1)：
θstart=θstart,s+θstart,b(3-1)；
Beam scanning angular speed is obtained by formula (3-2)：
ω=ωs+ωb(3-2)；
Terminate scan angle to be obtained by formula (3-3)：
θend=θstart+ω·Ta(3-3)；
Slide in beam bunching mode design and generally use θend=-θstart, to maximally utilize beam scanning capabilities, order：
θsteer=θend-θstart=ω Ta(3-4)；
Wherein, θsteerFor in imaging time section Ta, the scanning angle of SAR satellites.
Imaging region orientation length is obtained by formula (3-5)：
Wherein θaFor Azimuth beam width, λ is wavelength.
The equivalent orientation length D of antennaaObtained by formula (3-6)：
Wherein λ is the wavelength of Azimuth beam.
Pivot oblique distance is obtained by formula (3-7)：
Azimuth resolution is obtained by formula (3-8)：
In summary formula, it can be seen that by increasing wave beam angular velocity of rotation ω, R can be reducedrot, so as to effectively change
Kind azimuth resolution ρ.
The process that Azimuth beam sweep parameter is calculated, including acquisition parameter, target are set, parameter is calculated, parameter decomposition 4
Individual step.
Fig. 4-3 realizes schematic flow sheet for the synthetic aperture radar image-forming method of the embodiment of the present invention three, such as Fig. 4-3 institutes
Show, the described method comprises the following steps：
Step S431, acquisition parameter.
Here, the parameter includes but is not limited to be satellite velocities Vs, oblique distance R0, the equivalent orientation length D of antennaaAnd side
Position is to beam angle θa。
Step S432, imageable target parameter setting.
Here, the imageable target parameter can include but is not limited to be imaging region orientation length XsceneAnd orientation
Resolution ratio ρ.The imageable target parameter can staff set according to the actual requirements.
Step S433, imaging parameters are calculated.
Here, the imaging parameters include but is not limited to be wave beam angular velocity of rotation ω and rotational time Ta。
Known satellite speed Vs, oblique distance R0, the equivalent orientation length D of antennaaWith Azimuth beam width θa, in order to obtain
Imaging region orientation length XsceneWith azimuth resolution ρ, formula (3-9) is obtained according to formula (3-5), (3-7) and (3-8)
(specific derivation process is referring to embodiment two), wave beam angular velocity of rotation ω and rotation are obtained further according to formula (3-10) and (3-11)
Time Ta：
Wherein,
Step S434, parameter decomposition is carried out to ω.
Here, ω is decomposed, its constraints includes the mechanical maximum rotative speed ω of satellites,maxWith antenna beam most
Big electric scanning angle θb,max, that is, meet following condition：
For conventional SAR satellites, usual ωs,max＜ ω, therefore can use：
ωs=ωs,max
ωb=ω-ωs,max
So as to maximally utilize the mechanical scan capability of satellite, electric scanning angular speed is reduced, and then reduce electric scanning maximum angular
Spend θb, antenna bearingt can be so reduced to electric scanning graing lobe, be conducive to improving picture quality.
Step S435, judges whether the angular scanning speed of electric scanning meets constraints.
Here, judge whether the angular scanning speed of electric scanning meets constraints：ωbTa≤θb,maxIf the electricity is swept
The angular scanning speed retouched is met constraints and is then imaged into step S336 using the parameter, and step is entered if being unsatisfactory for
Rapid S332 is, it is necessary to be adjusted to picture zone aspect to length, XsceneWith azimuth resolution ρ, the calculating wave beam anglec of rotation is re-started
Speed omega and rotational time Ta。
Step S436, the ω obtained using step S335sAnd ωbMechanical scanning and electric scanning are carried out simultaneously, are imaged.
In embodiments of the present invention, because satellite inertial is big, and stable angular speed needs to be formed from being initially rotated to
Regular hour, therefore satellite need to turn to attitude one than the larger angle of pitch, and imaging start time starts to turn in advance
It is dynamic.To imaging start time, satellite reaches the specified angle of pitch, and forms stable rate of pitch.Electric scanning need not shift to an earlier date
Prepare, arrival imaging start time starts scanning, is similarly formed stable sweep speed.The actual wave beam formed on ground is swept
Retouch, be the Overlay of electric scanning and mechanical scanning.In synthetic aperture radar image-forming method provided in an embodiment of the present invention, together
When implement Azimuth beam electric scanning and mechanical scanning, electric scanning and mechanical scanning cooperate, and improve beam positional to scanning
Speed and scanning maximum angle, so as to lift the azimuth resolution of SAR image.
Example IV
The embodiment of the present invention provides a kind of synthetic aperture radar image-forming device, and Fig. 5 is the synthetic aperture of the embodiment of the present invention four
The composition structural representation of radar imagery device, as shown in figure 5, described device 500 includes：First determining module 501, second is true
Cover half block 502, the 3rd determining module 503, control module 504 and image-forming module 505, wherein：
First determining module 501, the first angular speed and imaging time for determining the SAR.
Here, first angular speed is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging.
First determining module 501 further comprises：
Collecting unit, the systematic parameter for gathering the SAR；
Acquiring unit, for obtaining imaging region orientation length set in advance and azimuth resolution；
First determining unit, for true according to the systematic parameter, imaging region orientation length and azimuth resolution
The fixed SAR enters the first angular speed and imaging time of line slip pack.
Second determining module 502, second jiao of speed is determined for the maximum angular velocity of rotation of machinery according to the SAR
Degree.
Here, second angular speed is the angular speed that the SAR carries out mechanical scanning.
3rd determining module 503, for determining the third angle according to first angular speed and second angular speed
Speed.
Here, the third angle speed is the angular speed that the SAR carries out electric scanning.
3rd determining module 503 further comprises：Second determining unit, for determining the 3rd according to formula (1-1)
Angular velocity omegab；Wherein, the ωaFor the second angular speed.
The control module 504, for according to the control of second angular speed, the third angle speed and imaging time
SAR carries out mechanical scanning and electric scanning, obtains echo data.
Here, the control module 504 further comprises：
First control unit, a length of imaging time during for controlling the SAR to be carried out according to second angular speed
Mechanical scanning；
Second control unit, a length of imaging time during for controlling the SAR to be carried out according to the third angle speed
Electric scanning；Wherein, at the beginning of the mechanical scanning between and the electric scanning at the beginning of between be spaced in the default time
In the range of.
The image-forming module 505, for entering line slip spotlight imaging according to the echo data.
It need to be noted that be：The description of above synthetic aperture radar image-forming device embodiment, implements with the above method
The description of example is similar, with the similar beneficial effect of same embodiment of the method, therefore is not repeated.For present invention synthesis hole
The ins and outs not disclosed in footpath radar imagery device embodiment, refer to the description of the inventive method embodiment and understand, be
Length is saved, therefore is repeated no more.
Embodiment five
Based on foregoing embodiment, the embodiment of the present invention provides a kind of synthetic aperture radar image-forming device again, and Fig. 5 is this hair
The composition structural representation of the bright synthetic aperture radar image-forming device of embodiment five, as shown in figure 5, described device 600 includes：First
Determining module 601, the second determining module 602, the 3rd determining module 603, the 4th determining module 604, judge module 605, control
Module 606, image-forming module 607 and the reminding module 608, wherein：
First determining module 601, the first angular speed and imaging time for determining the SAR.
Here, first angular speed is the angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging；
First determining module 601 further comprises：
Collecting unit, the systematic parameter for gathering the SAR；
Acquiring unit, for obtaining imaging region orientation length set in advance and azimuth resolution；
First determining unit, for true according to the systematic parameter, imaging region orientation length and azimuth resolution
The fixed SAR enters the first angular speed and imaging time of line slip pack.
Here, the systematic parameter at least includes：The flying speed V of the SARs, range Imaging scene most short oblique distance
R0, the equivalent orientation length D of antennaaWith Azimuth beam width θa, accordingly, first determining unit includes：
First determination subelement, for according to formula (2-1), determining pivot oblique distance Rrot；
Second determination subelement, for according to formula (2-3) and (2-4), determining that the SAR enters line slip spotlight imaging
Scanning angle θsteer；
3rd determination subelement, for determining the imaging time T according to formula (2-9)a；
4th determination subelement, for determining first angular velocity omega according to formula (2-10).
Second determining module 602, second jiao of speed is determined for the maximum angular velocity of rotation of machinery according to the SAR
Degree；Wherein, second angular speed is the angular speed that the SAR carries out mechanical scanning；
3rd determining module 603, for determining the third angle according to first angular speed and second angular speed
Speed.
Here, the third angle speed is the angular speed that the SAR carries out electric scanning.
3rd determining module 603 further comprises：Second determining unit, for determining the 3rd according to formula (1-1)
Angular velocity omegab；Wherein, the ωaFor the second angular speed.
4th determining module 604, for determining that the SAR carries out the maximum scan angle of electric scanning；
Whether the judge module 605, the product for judging second angular speed and the imaging time is not more than
The maximum scan angle of the electric scanning；
The control module 606, if the product for second angular speed and the imaging time be not more than it is described
The maximum scan angle of electric scanning, then control the SAR to carry out according to second angular speed, the third angle speed and imaging time
Mechanical scanning and electric scanning, obtain echo data.
Here, the control module 606 further comprises：
First control unit, a length of imaging time during for controlling the SAR to be carried out according to second angular speed
Mechanical scanning；
Second control unit, a length of imaging time during for controlling the SAR to be carried out according to the third angle speed
Electric scanning；Wherein, at the beginning of the mechanical scanning between and the electric scanning at the beginning of between be spaced in the default time
In the range of.
The image-forming module 607, for entering line slip spotlight imaging according to the echo data.
The reminding module 608, if the product for second angular speed and the imaging time is more than the electricity
The maximum scan angle of scanning, then prompting resets imaging region orientation length and azimuth resolution.
It need to be noted that be：The description of above synthetic aperture radar image-forming device embodiment, implements with the above method
The description of example is similar, with the similar beneficial effect of same embodiment of the method, therefore is not repeated.For present invention synthesis hole
The ins and outs not disclosed in footpath radar imagery device embodiment, refer to the description of the inventive method embodiment and understand, be
Length is saved, therefore is repeated no more.
It should be understood that " one embodiment " or " embodiment " that specification is mentioned in the whole text means relevant with embodiment
During special characteristic, structure or characteristic are included at least one embodiment of the present invention.Therefore, occur everywhere in entire disclosure
" in one embodiment " or " in one embodiment " identical embodiment is not necessarily referred to.In addition, these specific feature, knots
Structure or characteristic can be combined in one or more embodiments in any suitable manner.It should be understood that in the various implementations of the present invention
In example, the size of the sequence number of above-mentioned each process is not meant to the priority of execution sequence, and the execution sequence of each process should be with its work(
It can be determined with internal logic, any limit is constituted without tackling the implementation process of the embodiment of the present invention.The embodiments of the present invention
Sequence number is for illustration only, and the quality of embodiment is not represented.
It should be noted that herein, term " comprising ", "comprising" or its any other variant are intended to non-row
His property is included, so that process, method, article or device including a series of key elements not only include those key elements, and
And also including other key elements being not expressly set out, or also include for this process, method, article or device institute inherently
Key element.In the absence of more restrictions, the key element limited by sentence "including a ...", it is not excluded that including this
Also there is other identical element in process, method, article or the device of key element.
, can be by it in several embodiments provided herein, it should be understood that disclosed apparatus and method
Its mode is realized.Apparatus embodiments described above are only schematical, for example, the division of the unit, is only
A kind of division of logic function, can have other dividing mode, such as when actually realizing：Multiple units or component can be combined, or
Another system is desirably integrated into, or some features can be ignored, or do not perform.In addition, shown or discussed each composition portion
Coupling point each other or direct-coupling or communication connection can be the INDIRECT COUPLINGs of equipment or unit by some interfaces
Or communication connection, can be electrical, machinery or other forms.
The above-mentioned unit illustrated as separating component can be or may not be it is physically separate, it is aobvious as unit
The part shown can be or may not be physical location；Both a place can be located at, multiple network lists can also be distributed to
In member；Part or all of unit therein can be selected to realize the purpose of this embodiment scheme according to the actual needs.
In addition, each functional unit in various embodiments of the present invention can be fully integrated into a processing unit, also may be used
Be each unit individually as a unit, can also two or more units it is integrated in a unit；It is above-mentioned
Integrated unit can both be realized in the form of hardware, it would however also be possible to employ hardware adds the form of SFU software functional unit to realize.
One of ordinary skill in the art will appreciate that：Realizing all or part of step of above method embodiment can pass through
Programmed instruction related hardware is completed, and foregoing program can be stored in computer read/write memory medium, and the program exists
During execution, the step of execution includes above method embodiment；And foregoing storage medium includes：Movable storage device, read-only deposit
Reservoir (Read Only Memory, ROM), magnetic disc or CD etc. are various can be with the medium of store program codes.
Or, if the above-mentioned integrated unit of the present invention is realized using in the form of software function module and is used as independent product
Sale in use, can also be stored in a computer read/write memory medium.Understood based on such, the present invention is implemented
The part that the technical scheme of example substantially contributes to prior art in other words can be embodied in the form of software product,
The computer software product is stored in a storage medium, including some instructions are make it that a computer equipment (can be with
It is personal computer, server or network equipment etc.) perform all or part of each of the invention embodiment methods described.
And foregoing storage medium includes：Movable storage device, ROM, magnetic disc or CD etc. are various can be with Jie of store program codes
Matter.
The foregoing is only a specific embodiment of the invention, but protection scope of the present invention is not limited thereto, any
Those familiar with the art the invention discloses technical scope in, change or replacement can be readily occurred in, should all be contained
Cover within protection scope of the present invention.Therefore, protection scope of the present invention should be based on the protection scope of the described claims.
Claims (14)
1. a kind of synthetic aperture radar SAR imaging methods, it is characterised in that methods described includes：
Determine the first angular speed and imaging time of the SAR；Wherein, first angular speed be the SAR enter line slip gather
The angular speed of Azimuth beam scanning when beam is imaged；
Second angular speed is determined according to the maximum angular velocity of rotation of the machinery of the SAR；Wherein, second angular speed is described
SAR carries out the angular speed of mechanical scanning；
The third angle speed is determined according to first angular speed and second angular speed, wherein, the third angle speed is institute
State the angular speed that SAR carries out electric scanning；
Control the SAR to carry out mechanical scanning and electric scanning according to second angular speed, the third angle speed and imaging time, obtain
To echo data；
Line slip spotlight imaging is entered according to the echo data.
2. the method according to claim 1, it is characterised in that the first angular speed of the determination SAR and imaging
Time includes：
Gather the systematic parameter of the SAR；
Obtain imaging region orientation length set in advance and azimuth resolution；
The first angular speed of the SAR is determined according to the systematic parameter, imaging region orientation length and azimuth resolution
And imaging time.
3. the method according to claim 2, it is characterised in that the systematic parameter at least includes：The flight of the SAR
Speed Vs, range Imaging scene most short oblique distance R0, the equivalent orientation length D of antennaaWith Azimuth beam width θa, accordingly,
First angular speed that the SAR is determined according to the systematic parameter, imaging region orientation length and azimuth resolution
Include with imaging time：
According to formulaDetermine pivot oblique distance Rrot；Wherein, ρ is the azimuth resolution；
According to formulaWithDetermine that the SAR enters line slip spotlight imaging
Scanning angle θsteer；Wherein, XsceneFor the imaging region orientation length；
According to formulaDetermine the imaging time Ta；
According to formulaDetermine first angular velocity omega.
4. the method according to claim 1, it is characterised in that described according to first angular speed and described second jiao
Speed determines the third angle speed, including：
According to formula ωb=ω-ωsDetermine the third angle speed omegab；Wherein, the ωsFor the second angular speed, the ω is first
Angular speed.
5. the method according to claim 1, it is characterised in that described according to second angular speed, the third angle speed
Degree and imaging time control the SAR to carry out mechanical scanning and electric scanning, obtain before echo data, methods described also includes：
Determine that the SAR carries out the maximum scan angle of electric scanning；
Judge whether the product of second angular speed and the imaging time is not more than the maximum scan angle of the electric scanning；
If the product of second angular speed and the imaging time is not more than the maximum scan angle of the electric scanning, root
Control the SAR to carry out mechanical scanning and electric scanning according to second angular speed, the third angle speed and imaging time, obtain echo
Data.
6. the method according to claim 5, it is characterised in that methods described also includes：
If the product of second angular speed and the imaging time is more than the maximum scan angle of the electric scanning, point out
Reset imaging region orientation length and azimuth resolution.
7. according to any described method in claim 1-5, it is characterised in that described according to second angular speed, the 3rd
Angular speed and imaging time, which control the SAR to carry out mechanical scanning and electric scanning, to be included：
The mechanical scanning of a length of imaging time when controlling the SAR to be carried out according to second angular speed；
The electric scanning of a length of imaging time when controlling the SAR to be carried out according to the third angle speed；Wherein, the machinery
Being spaced in default time range between at the beginning of scanning and at the beginning of the electric scanning.
8. a kind of synthetic aperture radar SAR imaging devices, it is characterised in that described device includes：
First determining module, the first angular speed and imaging time for determining the SAR；Wherein, first angular speed is
The angular speed that Azimuth beam is scanned when the SAR enters line slip spotlight imaging；
Second determining module, the second angular speed is determined for the maximum angular velocity of rotation of machinery according to the SAR；Wherein, it is described
Second angular speed is the angular speed that the SAR carries out mechanical scanning；
3rd determining module, for determining the third angle speed according to first angular speed and second angular speed, wherein, institute
It is the angular speed that the SAR carries out electric scanning to state the third angle speed；
Control module, sweeps for controlling the SAR to carry out machinery according to second angular speed, the third angle speed and imaging time
Retouch and electric scanning, obtain echo data；
Image-forming module, for entering line slip spotlight imaging according to the echo data.
9. the device according to claim 8, it is characterised in that first determining module includes：
Collecting unit, the systematic parameter for gathering the SAR；
Acquiring unit, for obtaining imaging region orientation length set in advance and azimuth resolution；
First determining unit, for determining institute according to the systematic parameter, imaging region orientation length and azimuth resolution
State the first angular speed and imaging time that SAR enters line slip pack.
10. the device according to claim 8, it is characterised in that the systematic parameter at least includes：The SAR's flies
Scanning frequency degree Vs, range Imaging scene most short oblique distance R0, the equivalent orientation length D of antennaaWith Azimuth beam width θa, correspondence
Ground, first determining unit includes：
First determination subelement, for according to formulaDetermine pivot oblique distance Rrot；Wherein, ρ is described
Azimuth resolution；
Second determination subelement, for according to formulaWithIt is determined that described
SAR enters the scanning angle θ of line slip spotlight imagingsteer；Wherein, XsceneFor the imaging region orientation length；
3rd determination subelement, for according to formulaDetermine the imaging time Ta；
4th determination subelement, for according to formulaDetermine first angular velocity omega.
11. the device according to claim 8, it is characterised in that the 3rd determining module, including：
Second determining unit, for according to formula ωb=ω-ωsDetermine the third angle speed omegab；Wherein, the ωsFor second jiao
Speed, the ω is the first angular speed.
12. the device according to claim 8, it is characterised in that described device also includes：
4th determining module, for determining that the SAR carries out the maximum scan angle of electric scanning；
Whether judge module, the product for judging second angular speed and the imaging time is not more than the electric scanning
Maximum scan angle；
Control module, if the product for second angular speed and the imaging time is not more than the maximum of the electric scanning
Scanning angle, then control the SAR to carry out mechanical scanning and electricity according to second angular speed, the third angle speed and imaging time
Scanning, obtains echo data.
13. the device according to claim 12, it is characterised in that described device also includes：
Reminding module, if the maximum that the product for second angular speed and the imaging time is more than the electric scanning is swept
Angle is retouched, then prompting resets imaging region orientation length and azimuth resolution.
14. according to any described device in claim 8-13, it is characterised in that the control module includes：
First control unit, the machine of a length of imaging time during for controlling the SAR to be carried out according to second angular speed
Tool is scanned；
Second control unit, the electricity of a length of imaging time during for controlling the SAR to be carried out according to the third angle speed
Scanning；Wherein, at the beginning of the mechanical scanning between and the electric scanning at the beginning of between be spaced in default time range
It is interior.
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