CN106772367A - Long distance staring imaging device and method in the coding high-resolution of Terahertz frequency range aperture - Google Patents

Abstract

The invention belongs to radar imaging technology field, long distance staring imaging device and method in espespecially a kind of Terahertz frequency range aperture coding high-resolution.The imaging device includes terahertz sources module 1, transmitting antenna 2, automatically controlled secondary reflector array 3, parabola principal reflection mirror 4, reception antenna 5, Terahertz receiver module 6, memory 7 and system control main frame 8.The terahertz sources module is connected with transmitting antenna, and the automatically controlled secondary reflector array is connected with system control main frame；The parabola principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；Reception antenna gathers the scatter echo signal of target surface；Terahertz receiver module carries out low noise amplification, mixing and quadrature demodulation treatment to scatter echo signal；System control main frame is associated imaging to echo-signal and reference signal, obtains object reconstruction image.The present invention is obtained and exceeded with high resolution in the wave beam of bore conventional radar diffraction limit, and pattern switching speed is fast.

Description

Long distance staring imaging device and method in the coding high-resolution of Terahertz frequency range aperture

Technical field

The invention belongs to radar imaging technology field, and in particular to high resolution radar staring imaging technology, it is espespecially a kind of too Long distance staring imaging device and method in the coding high-resolution of hertz frequency range aperture.

Background technology

High resolution radar imaging is the important means for realizing battle reconnaissance, target detection and identification, is ensuring national strategy Safety, contention battlefield masters face has very important effect.Conventional microwave radar system can active probe, penetration capacity By force, can round-the-clock, all weather operations, but because microwave frequency is low, wavelength is long, angular resolution is low, and due to image-forming principle Limitation, it is necessary to be imaged integration time, it is impossible to realize frame frequency high, high-resolution forword-looking imaging.Synthetic aperture radar (SAR) and inverse conjunction Into aperture radar (ISAR) although imaging can obtain the high-resolution in transverse direction by synthetic aperture, the two is all relied on The relative motion of radar and target, under the conditions of forward sight, corner very little, even zero, it is impossible to staring imaging, limit SAR with Applications of the ISAR in some occasions.And optical pickocff can forword-looking imaging, wavelength is short, high resolution, and image taking speed is fast, but according to Rely in target emanation, it is poor to penetration capacitys such as cloud, cigarette, mist and barriers, easily by such environmental effects.And in true battlefield surroundings In, the target such as vehicle, strong point, personnel in generally requiring to penetrate outside the logarithm such as the smoke of gunpowder, haze km in remote operating distance is carried out Quick accurately detecting and identification, to guide us to realize that precision strike is provided with targeted elimination to enemy's military target by armament systems Information support.And existing radar imaging system be difficult to fully meet it is above-mentioned to high-resolution, frame frequency high, forward sight staring imaging application Demand.

Terahertz aperture coding high-resolution imaging Radar Technology refers to change imaging plane by automatically controlled secondary reflector array Terahertz emission space width distributed mutually obtains the imaging mode of target scattering coefficient distribution.Relative to microwave and light wave, too The frequency and wavelength of hertz fall between so that Terahertz radar has relatively large absolute bandwidth and imaging higher Resolution ratio, and penetration capacity is preferably imaged, aperture coding techniques is combined under same apertures antenna conditions, more it is also easy to produce many The irradiation mode of sample and faster pattern switching speed, the potentiality for carrying out target high-resolution imaging using echo are also bigger. Meanwhile, aperture coded imaging technology can realize forward sight staring imaging by target single snap.Therefore, it is expected to using limited Aperture, within the extremely short time obtain beyond with bore conventional radar diffraction limit resolution ratio.Although Terahertz aperture encodes High-resolution imaging Radar Technology has many advantages relative to conventional radar imaging technique, but it is urgently to be resolved hurrily still to there are some The image-forming range of problem, such as system is limited, and terahertz wave beam is difficult to the on-mechanical Uniform Scanning of imaging plane, imaging The quasi-optical design difficulty of system is larger etc..In consideration of it, in the urgent need to carry out in the coding high-resolution of Terahertz frequency range aperture long distance into As technical research, developing, there is frame frequency high, high-resolution, forward sight staring imaging ability and system imaging distance to cover in thousands of meters Long distance imaging device, the application for Terahertz radar in the field such as battle reconnaissance and warning, target detection and identification provides one New technological approaches.

The content of the invention

For above-mentioned technical problem, the present invention proposes a kind of device, can simultaneously take into account imaging resolution with imaging speed Degree, and is avoided that mechanical scanning of the imaging device to imaging plane, wherein, imaging plane refer to positioned at plane where target and The geometrical plane with specific dimensions comprising object cross section, as shown in figure 1, its size is joined by the structure of imaging device Number is determined.Concrete technical scheme is as follows：

Long distance staring imaging device in a kind of Terahertz frequency range aperture coding high-resolution, including terahertz sources module 1, hair Penetrate antenna 2, automatically controlled secondary reflector array 3, parabola principal reflection mirror 4, reception antenna 5, Terahertz receiver module 6, memory 7 with And system control main frame 8.

The terahertz sources module is connected with transmitting antenna, the terahertz sources letter that the terahertz sources module is produced Number, automatically controlled secondary reflector array is radiated to after emitted antenna in the form of terahertz wave beam；The automatically controlled secondary reflector array It is connected with system control main frame, loading hole footpath encodes the automatically controlled secondary reflector array simultaneously under the control of system control main frame Random phase shift factor and lens phase modulation factor, and the terahertz wave beam given off to transmitting antenna carries out aperture coding and phase Position modulation obtains Terahertz coding wave beam, and further by Terahertz coding beams reflected to parabola principal reflection mirror；The throwing Object plane principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；Reception antenna gathers the scatter echo signal of target surface And transmit to Terahertz receiver module, the Terahertz receiver module scatter echo signal is carried out low noise amplification, mixing and Quadrature demodulation is processed, and by the scatter echo signal output after treatment to the memory storage；To be believed based on terahertz sources Number deducing the reference signal that obtains is input into the memory storage；System control main frame calls the scattering after processing in memory Echo-signal is associated imaging with reference signal, obtains the reconstructed image of target.

Further, the height on the automatically controlled secondary reflector array vertical direction is l, and N number of battle array is included on vertical direction Unit, each array element refers to single independent reflection phase-shifting unit, and the ratio of l and N represents the pitch of single array element.As shown in Figure 1, Set up rectangular coordinate system, the origin of coordinates overlaps with the summit of parabola principal reflection mirror, transverse axis x positive directions to the right, longitudinal axis y positive directions Straight up, automatically controlled secondary reflector array and the level interval of transmitting antenna are e, and the level interval of focal plane is a together, with imaging The level interval of plane is b, and b also represents the detection range of described device simultaneously.Automatically controlled secondary reflector array lower extreme point and transmitting The vertical spacing of antenna is g, and the vertical spacing of upper extreme point and x-axis is d, the origin of coordinates together focal plane level interval (i.e.：Parabolic The focal length of face principal reflection mirror) it is p.

Further, there is the work of digital lens after the automatically controlled secondary reflector array loaded lenses phase modulation factor With the digital lens focal plane coincides with confocal face with parabola principal reflection mirror focal plane, and confocal face is flat with where transmitting antenna Face is conjugated on digital lens, and the automatically controlled secondary reflector array is full between focal plane and the level interval a and e of transmitting antenna together Foot states relation：

Wherein, f is the focal length of digital lens.

Further, the meridian plane equation of parabola principal reflection mirror is：

y²=4px, (2)

Present invention also offers long distance staring imaging method in a kind of coding high-resolution of Terahertz frequency range aperture, using above-mentioned Terahertz frequency range aperture coding high-resolution in long distance staring imaging device, specifically include following steps：

(S1) terahertz sources module produce terahertz sources signal, after emitted antenna in the form of terahertz wave beam spoke It is incident upon automatically controlled secondary reflector array；

(S2) system control main frame controls automatically controlled secondary reflector array loading aperture to encode random phase shift factor and lens phase Position modulation factor, and the terahertz wave beam given off to transmitting antenna carries out aperture coding and phase-modulation obtains Terahertz coding Wave beam, and further by Terahertz coding beams reflected to parabola principal reflection mirror；

(S3) parabola principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；

(S4) reception antenna gathers the scatter echo signal of target surface and transmits to Terahertz receiver module, the terahertz Hereby receiver module scatter echo signal is carried out low noise amplification, mixing and quadrature demodulation treatment, and by treatment after be scattered back Ripple signal output is to the memory storage；

(S5) deduced based on terahertz sources signal and obtain reference signal, and reference signal is input into the memory deposited Storage；

(S6) system control main frame calls the echo-signal after processing in memory to be associated at imaging with reference signal Reason, obtains the reconstructed image of target.

Further, the step (S2) is with the detailed process of (S3)：

Aperture of the system control main frame in following formula encodes random phase shift factor generation corresponding phase distribution map, and input is extremely Phase loading is completed on automatically controlled secondary reflector array：

P_C=random (p_l,p_h, m), (3)

Wherein, P_CRepresent that aperture encodes random phase shift factor, p_lAnd p_hRepresent respectively the interval upper limit of random phase shift and under Limit, random is represented and is applied uniform in phase shift interval to m-th array element on automatically controlled secondary reflector array vertical direction Distribution random phase, m is 1 to N natural number, i.e. m=1,2 ..., N；

Lens phase modulation factor generation corresponding phase distribution map of the system control main frame in following formula, input is to automatically controlled Phase loading is completed on secondary reflector array：

Wherein, P_LRepresent lens phase modulation factor, k=2 π f_c/ c, f_cThe centre frequency of wave beam is encoded for Terahertz, c is The light velocity, π values are pi, y_mIt is m-th ordinate of array element central point on automatically controlled secondary reflector array vertical direction, m is 1 To the natural number of N, i.e. m=1,2 ..., N；y₀For the phase center of lens phase modulation factor on automatically controlled secondary reflector array (makes Obtain P_L=1) where array element central point ordinate.Lens phase modulation factor is on phase center y_m=y₀Central Symmetry, in phase Position center, P_L=1, equivalent to not applying phase-modulation.

If the phase center y of lens phase modulation factor on automatically controlled secondary reflector array₀Initial position be A₁, and from A₁ Point moves to A₂Point, A₁Point and A₂Spacing is s, and A between point₁A₂The central point of line and automatically controlled secondary reflector array center point weight Close, basis is incident to A respectively₁Point and A₂The incidence angle combination mirror-reflection theorem of light determines Terahertz coding wave beam warp at point Cross the focus point B in confocal face after digital lens focus₁Point and B₂Point, B₁Point and B₂Point is located at parabola principal reflection mirror again simultaneously Focal plane on, and B₁Point and B₂Spacing is q between point.

A₁Point and A₂Distance s and B between point₁Point and B₂Spacing q is calculated by formula (5) and (6) respectively between point：

When phase center is located at A₂During point, now focus point is located at B₂Point, two reflection light A₁B₂And A₂B₂Hand over respectively and throw Object plane principal reflection mirror is in C₁And C₂, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₁And C₂2 points Coordinate (s₁,t₁) and (s₂,t₂), in conjunction with the fundamental property of parabola principal reflection mirror, then by parabola principal reflection mirror in C₁And C₂ Two rim ray slopes of the Terahertz coding wave beam of two point reflections are respectively：

Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：

D₁=k₂(p+a+b-t₂)+s₂-k₁(p+a+b-t₁)-s₁。 (9)

When phase center is located at A₁During point, now focus point is located at B₁Point, two reflection light A₁B₁And A₂B₁Hand over respectively and throw Object plane principal reflection mirror is in C₃And C₄, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₃And C₄2 points of seats Mark (s₃,t₃) and (s₄,t₄), then by parabola principal reflection mirror in C₃And C₄The Terahertz of two point reflections encodes two edges of wave beam Light slope k₃With k₄And the now dimension D of imaging plane Terahertz hot spot₂Calculated by formula (10) and formula (11) respectively：

k₃=k₄=0, (10)

D₂=s₄-s₃。 (11)

The longitudinal size h of the imaging plane and caliber size w of parabola principal reflection mirror is counted by formula (12) and formula (13) respectively Calculate：

H=s₄-k₁(p+a+b-t₁)-s₁, (12)

According to above-mentioned conclusion, to ensure that Terahertz coding wave beam carries out all standing scanning to imaging plane, lens phase is adjusted The phase center y of the factor processed₀Fixing moving step length from A on automatically controlled secondary reflector₁Point is to A₂Point movement, moving step length takes Value interval is calculated by following formula：

Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.

The Advantageous Effects obtained using the present invention：1st, the present invention encodes random phase shift factor at automatically controlled time using aperture Random phase shift is carried out at each array element of reflecting surface array to incident terahertz wave beam, and then changes imaging plane terahertz emission Field space width distributed mutually, finally enables imaging device obtain and exceeds with high-resolution in the wave beam of bore conventional radar diffraction limit Power, and pattern switching speed is fast, without being imaged integration time.2nd, the present invention makes automatically controlled time instead using the phase modulation factor of lens The face array of penetrating plays a part of digital lens, incident terahertz wave beam is focused and control is pointed to, while using parabola Principal reflection mirror is reflected wave beam and is collimated, and improves the transmission power in specific objective direction, clutter reduction/interference radiating way work( Rate, improve signal to noise ratio, so as to increase the EFFECTIVE RANGE of imaging system so that Terahertz encode wave beam middle long distance be imaged away from From above remaining that preferable collimation carries out on-mechanical all standing scanning to imaging plane, improve the imaging frame rate of device with it is steady It is qualitative.3rd, apparatus of the present invention and method, are capable of achieving long distance staring imaging device in the Terahertz frequency range aperture coding high-resolution Target during logarithm km is outer in remote operating distance carries out frame frequency high, high-resolution, forward sight and stares all standing scanning imagery.

Brief description of the drawings

Fig. 1 is the structural representation of apparatus of the present invention；

Fig. 2 is the inventive method schematic flow sheet；

In figure marked as：

1st, terahertz sources module, 2, transmitting antenna, 3, automatically controlled secondary reflector array, 4, parabola principal reflection mirror, 5, connect Receive antenna, 6, Terahertz receiver module, 7, memory, 8, system control main frame.

Specific embodiment

The invention will be further described with specific embodiment below in conjunction with the accompanying drawings.

In the present invention, it is contemplated that device mode of operation in the horizontal and vertical directions has symmetry, with side vertically The present invention will be described as a example by.Set up rectangular coordinate system as shown in Figure 1, the origin of coordinates and parabola principal reflection mirror Summit overlaps, and to the right, longitudinal axis y positive directions are straight up for transverse axis x positive directions.The present invention proposes a kind of Terahertz frequency range aperture and compiles Code high-resolution in long distance staring imaging device, as shown in Figure 1, described device include terahertz sources module 1, transmitting antenna 2, Automatically controlled secondary reflector array 3, parabola principal reflection mirror 4, reception antenna 5, Terahertz receiver module 6, memory 7 and system control Main frame processed 8.Wherein, system control main frame mainly includes three functions, respectively：For being controlled to automatically controlled secondary reflector array Make, reference signal is deduced and scatter echo signal and reference signal is carried out on the basis of terahertz sources signal Relevance imaging treatment.

The inventive method flow chart as shown in Fig. 2 terahertz sources module is connected with transmitting antenna, terahertz sources module The terahertz sources signal of generation, is radiated to automatically controlled secondary reflector array in the form of terahertz wave beam after emitted antenna；Electricity Control secondary reflector array is connected with system control main frame, and loading hole footpath coding is random simultaneously under the control of system control main frame moves Phase factor and lens phase modulation factor, and the terahertz wave beam given off to transmitting antenna carries out aperture coding and phase-modulation Terahertz coding wave beam is obtained, and further by Terahertz coding beams reflected to parabola principal reflection mirror；It is loaded with lens phase The automatically controlled secondary reflector array of position modulation factor has the effect of digital lens, the digital lens focal plane and parabola principal reflection Mirror focal plane coincides with confocal face, and parabola principal reflection mirror is reflected and collimated to Terahertz coding wave beam；Reception antenna is adopted Collect the scatter echo signal of target surface and transmit to Terahertz receiver module, Terahertz receiver module enters to scatter echo signal Row low noise amplification, mixing and quadrature demodulation treatment, and by the scatter echo signal output after treatment to the memory storage； The reference signal for obtaining will be deduced based on terahertz sources signal to be input into memory storage；System control main frame calls memory Echo-signal and reference signal and the existing parametric method of combination, orthogonal matching pursuit, matched filtering or sparse after middle treatment The data processing techniques such as reconstruct are associated imaging, obtain the reconstructed image of target.

In embodiment, the height on the automatically controlled secondary reflector array vertical direction is l, and N number of battle array is included on vertical direction Unit, each array element refers to single independent reflection phase-shifting unit, and automatically controlled secondary reflector array is e with the level interval of transmitting antenna, The level interval of focal plane is a together, is b, automatically controlled secondary reflector array lower extreme point and transmitting day with the level interval of imaging plane The vertical spacing of line is g, and the vertical spacing of upper extreme point and x-axis is d, the origin of coordinates together focal plane level interval (i.e.：Parabola The focal length of principal reflection mirror) it is p, A on automatically controlled secondary reflector array₁Point and A₂Spacing is s, and A between point₁A₂The central point of line Overlapped with automatically controlled secondary reflector array center point, therefore A₁Point coordinates is (a+p ,-d- (l+s)/2), A₂Point coordinates is (a+p ,-d- (l-s)/2).The ratio of l and N represents the pitch of single array element, and pitch is smaller, then can be on smaller unit yardstick to transmitting day The terahertz wave beam of beta radiation carries out aperture coding and phase-modulation, to obtain more preferable encoding efficiency and Wave beam forming ability, Its specific value is determined by the processing technology of automatically controlled secondary reflector array, with the reflective phased array plane day based on crystal liquid substrate As a example by line, array element pitch is usually hundreds of microns.B represents the detection range of device of the present invention, and usually 2000.00m is extremely Middle long distance areas imaging in the range of 10000.00m.Transmitting antenna will not be right with automatically controlled secondary reflector array in device is ensured Terahertz coding wave beam is produced on the premise of blocking, can be by the physical dimension that reduces the value of g and d to reduce system, generally Can be set in the interval of 0.01m to 0.05m.The value of a, p and e can be set in the interval of 1.00m to 5.00m.

In the present invention, automatically controlled secondary reflector array meets following between focal plane and the level interval a and e of transmitting antenna together Relation：

Wherein, f is the focal length of digital lens.

In the present invention, the meridian plane equation of parabola principal reflection mirror is：

y²=4px.

As shown in figure 1, phase center (the ordinate of array element central spot where phase center of lens phase modulation factor As y in formula (4)₀Value) from A₁Point moves to A₂Point, now according to the incidence angle combination minute surface for being incident to light at the point Reflection theorem can determine that Terahertz encodes wave beam by the focus point respectively B after digital lens focus in confocal face₁Point and B₂ Point.B₁Point and B₂Point is located on the focal plane of parabola principal reflection mirror again simultaneously, and B₁Point and B₂Spacing is q, B between point₁Point is sat It is designated as (p, 0), B₂Point coordinates is (p, q).

When the phase center of lens phase modulation factor is located at A₁During point, closed according to mirror-reflection theorem and light path geometry System, derives：

When the phase center of lens phase modulation factor is located at A₂During point, can similarly obtain：

When phase center is located at A₂During point, now focus point is located at B₂Point, two reflection light A₁B₂And A₂B₂Hand over respectively and throw Object plane principal reflection mirror is in C₁And C₂, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₁And C₂2 points Coordinate (s₁,t₁) and (s₂,t₂), in conjunction with the fundamental property of parabola principal reflection mirror, then by parabola principal reflection mirror in C₁And C₂ Two rim ray slopes of the Terahertz coding wave beam of point reflection are respectively：

Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：

D₁=k₂(p+a+b-t₂)+s₂-k₁(p+a+b-t₁)-s₁。

When phase center is located at A₁During point, now focus point is located at B₁Point, two reflection light A₁B₁And A₂B₁Hand over respectively and throw Object plane principal reflection mirror is in C₃And C₄, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₃And C₄2 points of seats Mark (s₃,t₃) and (s₄,t₄), then by parabola principal reflection mirror in C₃And C₄The Terahertz of two point reflections encodes two edges of wave beam Light slope k₃With k₄And the now dimension D of imaging plane Terahertz hot spot₂Calculated by following formula respectively：

k₃=k₄=0,

D₂=s₄-s₃。

The longitudinal size h of the imaging plane and caliber size w of parabola principal reflection mirror is calculated by following formula respectively：

H=s₄-k₁(p+a+b-t₁)-s₁,

According to above-mentioned conclusion, to ensure that Terahertz coding wave beam carries out all standing scanning to imaging plane, lens phase is adjusted The phase center y of the factor processed₀Must be with particular step size from A on automatically controlled secondary reflector₁Point is to A₂Point movement, moving step length takes Value interval is calculated by following formula：

Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.

In the present invention, the method that the relevance imaging treatment is used includes existing parametric method, orthogonal matching pursuit, matching Filtering or sparse reconstruct etc..The method that relevance imaging treatment is used can only with a kind of above-mentioned method, or wherein Several method is used in combination.

In the present invention, the automatically controlled secondary reflector array of described device can be put down using the reflective phased array based on crystal liquid substrate Surface antenna, also can be using the reflective phased array flat plane antenna based on Meta Materials technology.

Below by taking the reflective phased array flat plane antenna based on crystal liquid substrate as an example, determine that automatically controlled secondary reflector array is vertical Height l=0.10m on direction, includes 200 array elements, i.e. N=200, automatically controlled secondary reflector array and transmitting on vertical direction The level interval of antenna is e=1.00m, and the level interval with imaging plane is b=2500.00m, under automatically controlled secondary reflector array The vertical spacing of end points and transmitting antenna is g=0.02m, and upper extreme point and the vertical spacing of x-axis are d=0.01m, the origin of coordinates with The level interval in confocal face is (i.e.：The focal length of parabola principal reflection mirror) it is p=5.00m, the focal length f=0.50m of digital lens.

With reference to above-mentioned parameter, the level interval a=of automatically controlled secondary reflector array focal plane together is calculated by formula (1) 1.00m。

System control main frame encodes random phase shift factor P according to aperture_C(- 0.5 π, 0.5 π m) generate correspondence to=random Phase distribution figure, to completing phase loading on automatically controlled secondary reflector array, wherein m is 1 to 200 natural number, i.e. m=1 for input, 2 ..., 200.Meanwhile, system control main frame is according to lens phase modulation factorGeneration corresponding phase distribution Figure, completes phase loading in input to automatically controlled secondary reflector array.Wherein, k=2 π f_c/ c, the center of Terahertz coding wave beam is frequently Rate f_c=300.00GHz, light velocity c=3 × 10⁸m/s。y_mIt is m-th array element central point on automatically controlled secondary reflector array vertical direction Ordinate, m is 1 to 200 natural number, i.e. m=1,2 ..., 200.y₀To be located at A on automatically controlled secondary reflector array₁Point and A₂ The ordinate of array element central point where lens phase modulation factor phase center between point.In embodiment, each array element center Point ordinate can according to automatically controlled secondary reflector array sizes with comprising array number calculated.

A on automatically controlled secondary reflector array is calculated according to formula (5)₁Point and A₂Spacing is s=0.01m, and A between point₁A₂ Central point overlaps with automatically controlled secondary reflector array center point, then A₁Point coordinates is (6, -0.065), A₂Point coordinates for (6 ,- 0.055).B is calculated according to formula (6)₁Point and B₂Spacing is q=0.02m between point, then B₁Point coordinates is (5,0), B₂Point is sat It is designated as (5,0.02).

When phase center is located at A₂During point, C can be obtained₁Point and C₂Point coordinate be respectively (0.17,0.0014) and (0.67, 0.02) two rim ray slope ks of Terahertz coding wave beam after collimation are calculated, and by formula (7) and formula (8) respectively₁=- 0.0040 and k₂=-0.0039, then calculate the dimension D of the outer imaging plane Terahertz hot spots of now 2500.00m according to formula (9)₁= 0.63m。

When phase center is located at A₁During point, C can be obtained₃Point and C₄Point coordinate be respectively (0.050,0.00013) and (0.55,0.015), two rim ray slope ks are understood by formula (10)₃=k₄=0, and understood now by formula (11) The dimension D of the imaging plane Terahertz hot spot at 2500.00m₂=0.50m.

The longitudinal size h=10.39m and parabola master for calculating imaging plane according to formula (12) and formula (13) respectively are anti- Penetrate the caliber size w=0.62m of mirror.

The phase center y of lens phase modulation factor is obtained finally according to formula (14)₀In automatically controlled secondary reflector from A₁Point to A₂The interval of the mobile step-length of point is 0.00048m≤Δ≤0.00053m, therefore, step-length may be selected in implementation process Δ=0.0005m.

Imaging plane of the imaging device at the 2500.00m that adjusts the distance enters in drawing the present embodiment according to said structure index During row blocked scan, scanning light spot change in size scope be 0.50m~0.63m, almost maintain it is constant, illustrate be at this Terahertz coding wave beam has good collimation property under system framework, and the imaging performance such as resolution ratio for lifting imaging system has It is significant.

The explanation of the preferred embodiment of the present invention contained above, this be in order to describe technical characteristic of the invention in detail, and It is not that the content of the invention is limited in the concrete form described by embodiment, other modifications carried out according to present invention purport Also protected by this patent with modification.The purport of present invention is to be defined by the claims, rather than by the specific of embodiment Description is defined.

Claims (6)

1. a kind of Terahertz frequency range aperture encodes long distance staring imaging device in high-resolution, it is characterised in that：Including Terahertz hair Penetrate module (1), transmitting antenna (2), automatically controlled secondary reflector array (3), parabola principal reflection mirror (4), reception antenna (5), terahertz Hereby receiver module (6), memory (7) and system control main frame (8)；

The terahertz sources module is connected with transmitting antenna, the terahertz sources signal that the terahertz sources module is produced, Automatically controlled secondary reflector array is radiated to after emitted antenna in the form of terahertz wave beam；The automatically controlled secondary reflector array be System control main frame connection, loading hole footpath coding is random simultaneously under the control of system control main frame for the automatically controlled secondary reflector array Phase shift factor and lens phase modulation factor, and the terahertz wave beam given off to transmitting antenna carries out aperture coding with phase tune Terahertz coding wave beam is obtained, and further by Terahertz coding beams reflected to parabola principal reflection mirror；The parabola Principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；The scatter echo signal of reception antenna collection target surface is simultaneously passed Terahertz receiver module is transported to, the Terahertz receiver module carries out low noise amplification to scatter echo signal, is mixed and orthogonal Demodulation process, and by the scatter echo signal output after treatment to the memory storage；System control main frame calls memory Scatter echo signal after middle treatment is associated imaging with the reference signal obtained based on the deduction of terahertz sources signal, Obtain the reconstructed image of target.

2. a kind of Terahertz frequency range aperture according to claim 1 encodes long distance staring imaging device in high-resolution, and it is special Levy and be：Height on the automatically controlled secondary reflector array vertical direction is l, and N number of array element, each array element are included on vertical direction Refer to single independent reflection phase-shifting unit, the ratio of l and N represents the pitch of single array element；Set up rectangular coordinate system, the origin of coordinates Summit with parabola principal reflection mirror overlaps, transverse axis x positive directions to the right, longitudinal axis y positive directions straight up, automatically controlled secondary reflector battle array Row are e with the level interval of transmitting antenna, and the level interval of focal plane is a together, are b with the level interval of imaging plane；It is automatically controlled The vertical spacing of secondary reflector array lower extreme point and transmitting antenna is g, and upper extreme point and the vertical spacing of x-axis are d, the origin of coordinates with The level interval in confocal face is (i.e.：The focal length of parabola principal reflection mirror) it is p.

3. a kind of Terahertz frequency range aperture according to claim 2 encodes long distance staring imaging device in high-resolution, and it is special Levy and be：There is the effect of digital lens, the numeral after described automatically controlled secondary reflector array loaded lenses phase modulation factor Lens focal plane coincides with confocal face with parabola principal reflection mirror focal plane, and confocal face is with plane where transmitting antenna on numeral Lens are conjugated, and the automatically controlled secondary reflector array meets following passes between focal plane and the level interval a and e of transmitting antenna together System：

$a=\frac{fe}{e-f},---\left(1\right)$

Wherein, f is the focal length of digital lens.

4. a kind of Terahertz frequency range aperture encodes long distance staring imaging method in high-resolution, it is characterised in that：Will using such as right Ask the Terahertz frequency range aperture described in 2 or 3 to encode long distance staring imaging device in high-resolution, specifically include following steps：

(S1) terahertz sources module produces terahertz sources signal, is radiated in the form of terahertz wave beam after emitted antenna Automatically controlled secondary reflector array；

(S2) system control main frame controls automatically controlled secondary reflector array loading aperture to encode random phase shift factor and lens phase tune The factor processed, and the terahertz wave beam given off to transmitting antenna carries out aperture coding and phase-modulation obtains Terahertz coding ripple Beam, and further by Terahertz coding beams reflected to parabola principal reflection mirror；

(S3) parabola principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；

(S4) reception antenna gathers the scatter echo signal of target surface and transmits to Terahertz receiver module, and the Terahertz connects Receiving module carries out low noise amplification, mixing and quadrature demodulation treatment to scatter echo signal, and the scatter echo after treatment is believed Number output is to the memory storage；

(S5) deduced based on terahertz sources signal and obtain reference signal, and reference signal is input into the memory storage；

(S6) system control main frame calls the scatter echo signal after processing in memory to be associated at imaging with reference signal Reason, obtains the reconstructed image of target.

5. a kind of Terahertz frequency range aperture according to claim 4 encodes long distance staring imaging method in high-resolution, and it is special Levy and be：The specific design process of the step (S2) is：

If the phase center initial position of lens phase modulation factor is A on automatically controlled secondary reflector array₁, and from A₁Point moves to A₂ Point, A₁Point and A₂Spacing is s, and A between point₁A₂The central point of line overlaps with automatically controlled secondary reflector array center point, this time-division Basis is not incident to A₁Point and A₂The incidence angle combination mirror-reflection theorem of light determines Terahertz coding wave beam by numeral at point In the focus point B in confocal face after lens focus₁Point and B₂Point, B₁Point and B₂Jiao that point is located at parabola principal reflection mirror again simultaneously puts down On face, and B₁Point and B₂Spacing is q between point；

A₁Point and A₂Distance s and B between point₁Point and B₂Spacing q is calculated by formula (5) and formula (6) respectively between point：

$s=\frac{2ag-2de-el+al}{a+e},---\left(5\right)$

$q=\frac{2ag+as+es+al-le-2de}{2e}.---\left(6\right)$

6. a kind of Terahertz frequency range aperture according to claim 4 encodes long distance staring imaging method in high-resolution, and it is special Levy and be：The specific design process of the step (S3) is：

When phase center is located at A₂During point, now focus point is located at B₂Point, two reflection light A₁B₂And A₂B₂Parabola is handed over respectively Principal reflection mirror is in C₁And C₂, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₁And C₂2 points of coordinate (s₁,t₁) and (s₂,t₂), in conjunction with the fundamental property of parabola principal reflection mirror, then by parabola principal reflection mirror in C₁And C₂2 points Two rim ray slopes of the Terahertz coding wave beam of reflection are respectively：

$k_1=\frac{{\mathrm{qt}}_1-qp}{p^2+2q\sqrt{{\mathrm{pt}}_1}+2{\mathrm{pt}}_1+{t_1}^2},---\left(7\right)$

$k_2=\frac{{\mathrm{qt}}_2-qp}{p^2+2q\sqrt{{\mathrm{pt}}_2}+2{\mathrm{pt}}_2+{t_2}^2};---\left(8\right)$

Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：

D₁=k₂(p+a+b-t₂)+s₂-k₁(p+a+b-t₁)-s₁； (9)

When phase center is located at A₁During point, now focus point is located at B₁Point, two reflection light A₁B₁And A₂B₁Parabola is handed over respectively Principal reflection mirror is in C₃And C₄, C is calculated respectively with reference to the meridian plane equation of parabola principal reflection mirror at 2 points₃And C₄2 points of coordinate (s₃,t₃) and (s₄,t₄), then by parabola principal reflection mirror in C₃And C₄The Terahertz of two point reflections encodes two edge-lights of wave beam Line slope k₃With k₄And the now dimension D of imaging plane Terahertz hot spot₂Calculated by formula (10) and formula (11) respectively：

k₃=k₄=0, (10)

D₂=s₄-s₃； (11)

The longitudinal size h of the imaging plane and caliber size w of parabola principal reflection mirror is calculated by formula (12) and formula (13) respectively：

H=s₄-k₁(p+a+b-t₁)-s₁, (12)

$w=|C2-C3|=\sqrt{{(s_2-s_3)}^2+{(t_2-t_3)}^2};---\left(13\right)$

To ensure that Terahertz coding wave beam carries out all standing scanning to imaging plane, the phase center of lens phase modulation factor exists Fixing moving step length from A on automatically controlled secondary reflector₁Point is to A₂Point movement, the interval of moving step length is calculated by following formula：

$\frac{s}{Ceil(h/D_2)}\≤\mathrm{\Δ}\≤\frac{s}{Ceil(2h/(D_1+D_2\left)\right)},---\left(14\right)$

Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.