CN103308911B - Based on the microdisplacement measurement method and system of range gate deception technology - Google Patents

Abstract

The invention discloses a kind of microdisplacement measurement method and system based on range gate deception technology, belong to building deformation field of measuring technique.This method installs multiple microwave coherent reflection device on testee, fixedly mounting ground interferometer radar, and microwave coherent reflection device is positioned within ground interferometer radar beam area away from testee place; Ground interferometer radar is to microwave coherent reflection device radiation radar signal, carry out Late phase ginseng after each microwave coherent reflection device receives signal and be forwarded back to ground interferometer radar again, after ground interferometer radar receives the signal reflected through delay coherent, identify each microwave coherent reflection device, interfere measurement technique is adopted to calculate twice phase differential before and after signal, and by calculating the micrometric displacement amount of each microwave coherent reflection device.The passive corrner reflector signal that this method overcomes dense distribution is difficult to the problem be separated, and achieves multi-target measurement, and antijamming capability is strong, can be advantageously applied in the microdisplacement measurement of buildings.

Description

Based on the microdisplacement measurement method and system of range gate deception technology

Technical field

The invention belongs to building deformation field of measuring technique, relate to a kind of microdisplacement measurement method and system based on range gate deception technology.

Background technology

Can under the effect of various influence factor at occurring in nature buildings, its shape, size, position can change in time domain space, as the swing of high-rise, dam deformation etc.And when deflection exceedes the allowed band that deformable body can bear, then bring serious disaster can to the productive life of the mankind.Therefore deformation monitoring carries out to object significant.

Patent CN1542407A proposes a kind of microdisplacement measurement method, the method places a passive corrner reflector in point being monitored, a microwave is placed than phase measurement mechanism in monitoring point, microwave launches a single-frequency microwave than the radiating portion of phase measurement mechanism to corner reflector, corner reflector is made up of three blocks of aluminium sheets, and it is returned the microwave inciding it by original route total reflection.Than the microwave signal that the receiving unit acceptance angle reflector reflects of phase measurement mechanism is returned, through carrying out than mutually recording micrometric displacement amount with transmitting.This measuring method is with low cost, safety easy to use.But the greatest problem that the method exists in actual use is: be single-frequency continuous wave radar, the micrometric displacement of single microwave emitter can only be measured, can not multi-target measurement be realized; And due in the micrometric displacement testing of building, generally all need to arrange multiple point being monitored, therefore, said method receives many restrictions in the displacement monitoring process of reality.

The application is improved for this problem, makes corner reflector be no longer simple reflection unit, but is improved to the response type micro-wave reverberator with signal handling capacity.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of microdisplacement measurement method and system based on range gate deception technology, by carrying out coherent delay to the received signal, achieve " range gate deception ", multiple different microwave reflector is identified thus in monitoring point, adopt interfere measurement technique to calculate twice, front and back phase differential again, obtain the micrometric displacement amount of each microwave reflector.

For achieving the above object, the invention provides following technical scheme:

A kind of microdisplacement measurement method based on range gate deception technology, the method installs multiple microwave coherent reflection device on testee, fixedly mounting ground interferometer radar away from testee place, and microwave coherent reflection device is positioned within ground interferometer radar beam area; Ground interferometer radar is to microwave coherent reflection device radiation radar signal, carry out Late phase ginseng after each microwave coherent reflection device receives signal and be forwarded back to ground interferometer radar again, after ground interferometer radar receives the signal reflected through delay coherent, identify each microwave coherent reflection device, interfere measurement technique is adopted to calculate twice phase differential before and after signal, and by calculating the micrometric displacement amount of each microwave coherent reflection device.

Further, described ground interferometer radar adopts chirp-pulse compression radar or pseudo-random code phase-modulated pulse compression radar.

Further, microwave coherent reflection device adopts the form based on direct radio frequency coherent transponding to realize postponing, microwave coherent reflection device receives the signal from ground interferometer radar, postpones through delay line, then sends it back ground interferometer radar after amplifier amplifies.

Further, microwave coherent reflection device adopts digital RF memory technology DRFM to realize postponing.

Present invention also offers a kind of micro-displacement measuring system based on range gate deception technology, this system comprises the multiple microwave coherent reflection devices be arranged on testee, away from the hard-wired ground interferometer radar in testee place; Ground interferometer radar is to microwave coherent reflection device radiation radar signal, carry out Late phase ginseng after each microwave coherent reflection device receives signal and be forwarded back to ground interferometer radar again, after ground interferometer radar receives the signal reflected through delay coherent, identify each microwave coherent reflection device, interfere measurement technique is adopted to calculate twice phase differential before and after signal, and by calculating the micrometric displacement amount of each microwave coherent reflection device.

Further, the circuit structure of described microwave coherent reflection device comprises lag line, amplifier, circulator and antenna; After antenna receives signal, signal amplifies after delay line postpones, and sends it back ground interferometer radar again through amplifying signal by antenna.

Further, the circuit structure of described ground interferometer radar comprises dual-mode antenna, Up/Down Conversion channel, signal generator, matched filtering circuit, interferometry module and micrometric displacement Deformation calculation module.

Beneficial effect of the present invention is: the microdisplacement measurement method and system based on range gate deception technology of the present invention overcome in prior art carry out buildings micrometric displacement monitoring time dense distribution passive corrner reflector signal be difficult to be separated problem, achieve multi-target measurement, antijamming capability is strong, can be advantageously applied in the microdisplacement measurement of buildings.

Accompanying drawing explanation

In order to make object of the present invention, technical scheme and beneficial effect clearly, the invention provides following accompanying drawing and being described:

Fig. 1 is system construction drawing of the present invention;

Fig. 2 is the real Range Profile schematic diagram of microwave coherent reflection device;

Fig. 3 is microwave coherent reflection device circuit structure diagram;

Fig. 4 is ground interferometer radar circuit structure diagram.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described in detail.

Fig. 1 is system construction drawing of the present invention, as shown in the figure, native system is by the multiple microwave coherent reflection device be arranged on testee and forming away from the hard-wired ground interferometer radar in testee place, microwave coherent reflection device is arranged on testee, and they are positioned within ground interferometer radar antenna beam scope; Ground interferometer radar is away from measured object, and its installation site immobilizes.Ground interferometer radar is to microwave coherent reflection device radiation radar signal, microwave coherent reflection device carries out the receiving antenna that Late phase ginseng is transmitted to ground interferometer radar after receiving, postponing coherent forwarding capability makes microwave coherent reflection device move to different virtual locations respectively, exceed distance by radar resolution element, these microwave coherent reflection devices can be differentiated/identify to such radar receiver, adopt interfere measurement technique to calculate twice, front and back phase differential, the micrometric displacement amount of each microwave coherent reflection device can be obtained.

Specifically, suppose testee to be installed n microwave coherent reflection device, the physical location of their distance radars is respectively R ₁, R ₂..., R _n, these microwave coherent reflection devices are positioned within radar antenna beam area, and drop within distance by radar resolution element.Range Profile during these target independent measurements is as represented in the fine line in Fig. 2, and that leans on is very near, and when measuring together, its Range Profile is as represented in heavy line, and these microwave coherent reflection devices cannot be distinguished; Use for reference " range gate deception " thought in electronic countermeasure field in the present invention, reverberator is improved, these reverberators are moved to different virtual location R respectively ₁, R ' ₂..., R ' _n, Range Profile when these targets are measured together is as in Fig. 2, dotted line represents, and what they had divided opens very much, exceedes the Range resolution unit of radar, and these microwave coherent reflection devices are just easy to differentiate and identify.

Fig. 3 is microwave coherent reflection device circuit structure diagram, and incoming signal carries out forwarding after delay is amplified going back by the microwave coherent reflection device in the present invention again, is equivalent to microwave coherent reflection device to move to a virtual location.The delay introduced due to microwave coherent reflection device is fixing, and when carrying out interferometry micrometric displacement, its phase place introduced has been cancelled, and this does not affect the measurement of micrometric displacement.Microwave coherent reflection device is by dual-mode antenna, and circulator, amplifier, and the formation such as delay circuit, both can adopt the form of direct radio frequency coherent transponding to realize postponing in the present invention, and digital RF memory technology DRFM also can be adopted to realize postponing.

Fig. 4 is ground interferometer radar circuit structure diagram, ground interferometer radar microwave radiation signal, irradiate all microwave coherent reflection devices, and receive the mixing echoed signal of microwave coherent reflection device, adopt matched filtering signal processing technology, form plural range image signal, the position that range value is large is the virtual location of microwave coherent reflection device, adopt interfere measurement technique, before and after calculating, the phase differential of twice complex image signal, can obtain the micrometric displacement amount of each microwave coherent reflection device.The microwave signal of radar emission can not be single-frequency continuous wave signal, can be linear frequency modulation continuous wave signal or binary phase coded modulation continuous wave signal etc.Ground interferometer radar main circuit will comprise, dual-mode antenna, Up/Down Conversion channel, signal generator, matched filtering/related operation, interference computing, micrometric displacement Deformation calculation module etc.

Specifically, suppose that the complex baseband signal of radar emission is by the radiofrequency signal of aerial radiation be:

$s_t\left(t\right)=\mathrm{rect}\left(\frac{t}{T}\right)x\left(t\right)e^{j2\mathrm{\πft}}$ (formula 1)

for rectangular pulse signal, rect.p. width is T, and the pulse repetition time is T _r;

The radiofrequency signal that each microwave coherent reflection device receives is:

$s_i\left(t\right)=\mathrm{rect}\left(\frac{t-R_i/c}{T}\right)x(t-R_i/c)e^{j2\mathrm{\πf}(t-R_i/c)}$ (formula 2)

Signal through postponing to forward again is:

$s_i\left(t\right)=\mathrm{rect}\left(\frac{t-R_i/c-{\mathrm{\τ}}_i}{T}\right)x(t-R_i/c-{\mathrm{\τ}}_i)e^{j2\mathrm{\πf}(t-R_i/c-{\mathrm{\τ}}_i)}$ (formula 3)

τ in above formula _irepresent the time delay of lag line.

Then the reflected signal of each microwave coherent reflection device of radar reception is:

$s_i\left(t\right)=\mathrm{rect}\left(\frac{t-2R_i/c-{\mathrm{\τ}}_i}{T}\right)x(t-2R_i/c-{\mathrm{\τ}}_i)e^{j2\mathrm{\πf}(t-2R_i/c-{\mathrm{\τ}}_i)}$ (formula 5)

This formula can be written as again:

$s_i\left(t\right)=\mathrm{rect}\left(\frac{t-2R_i^{\′}/c}{T}\right)x(t-2R_i^{\′}/c)e^{j2\mathrm{\πf}(t-2R_i^{\′}/c)}$ (formula 6)

Here R ' _i=R _i+ c τ _i/ 2; Represent the virtual location of microwave coherent reflection device distance radar.

Signal is down-converted to zero-base band signal by radar receiver:

$s_i\left(t\right)=\mathrm{rect}\left(\frac{t-2R_i^{\′}/c}{T}\right)x(t-2R_i^{\′}/c)e^{j2\mathrm{\πf}(-2R_i^{\′}/c)}$ (formula 7)

This signal is done matched filter operation, and the complex pattern signal obtaining each target is:

$s_i\left(t\right)=R_{\mathrm{xx}}(t-2R_i^{\′}/c)e^{j2\mathrm{\πf}(-2R_i^{\′}/c)}$ (formula 8)

Total complex pattern (Range Profile) signal is:

$s_r\left(t\right)={\mathrm{\Σ}}_{i=1}^n{s}_i\left(t\right)={\mathrm{\Σ}}_{i=1}^n{R}_{\mathrm{xx}}(t-2R_i^{\′}/c)e^{j2\mathrm{\πf}(-2R_i^{\′}/c)}$ (formula 9)

The position that this complex pattern modulus value is larger, corresponding to the virtual location of microwave coherent reflection device.

Suppose that 2 interferometry times are respectively: t _kand t _k+1, t _ktime each microwave coherent reflection device and radar between distance be respectively: R ₁, R ₂..., R _n, t _k+1the micrometric displacement amount of Shi Fasheng is respectively: Δ R ₁, Δ R ₂..., Δ R _n.

Adopt interfere measurement technique, calculate t _kand t _k+1time, the phase differential of complex pattern:

$\mathrm{\Φ}(t_k,t_{k+1})=\mathrm{angle}(s_r\left(t_k\right)\·s_r^{*}\left(t_{k+1}\right))$ (formula 10)

Here angle is the function asking plural phase angle.

Because microwave coherent reflection device moves to different virtual locations respectively, be greater than distance by radar resolution element, the real Range Profile of each microwave reflection point is (for Modulation Continuous Wave Radar, for sinc function, being two-valued function for m sequential binary phase encoding modulated continuous wave radar) main lobe numerical value is larger, secondary lobe numerical value is very little, and thus above formula is equivalent to:

${\mathrm{\Φ}}_i(t_k,t_{k+1})=\mathrm{angle}(s_i\left(t_k\right)\·s_i^{*}\left(t_{k+1}\right))=4\mathrm{\πf}(\mathrm{\Δ}{R}_i/c)=4\mathrm{\π\Δ}{R}_i/\mathrm{\λ}$ (formula 11)

In above formula, λ is radar wavelength.

Thus, each microwave reflector can be recorded at t _kand t _k+1between occur micrometric displacement amount be:

Δ R _i=λ Φ _i(t _k, t _k+1)/4 π (formula 12)

What finally illustrate is, above preferred embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although by above preferred embodiment to invention has been detailed description, but those skilled in the art are to be understood that, various change can be made to it in the form and details, and not depart from claims of the present invention limited range.

Claims (7)

1. the microdisplacement measurement method based on range gate deception technology, it is characterized in that: the method installs multiple microwave coherent reflection device on testee, fixedly mounting ground interferometer radar away from testee place, and microwave coherent reflection device is positioned within ground interferometer radar beam area; Ground interferometer radar is to microwave coherent reflection device radiation radar signal, carry out Late phase ginseng after each microwave coherent reflection device receives signal and be forwarded back to ground interferometer radar again, after ground interferometer radar receives the signal reflected through delay coherent, identify each microwave coherent reflection device, interfere measurement technique is adopted to calculate twice phase differential before and after signal, and by calculating the micrometric displacement amount of each microwave coherent reflection device.

2. the microdisplacement measurement method based on range gate deception technology according to claim 1, is characterized in that: described ground interferometer radar adopts chirp-pulse compression radar or pseudo-random code phase-modulated pulse compression radar.

3. the microdisplacement measurement method based on range gate deception technology according to claim 1, it is characterized in that: microwave coherent reflection device adopts the form based on direct radio frequency coherent transponding to realize postponing, microwave coherent reflection device receives the signal from ground interferometer radar, postpone through delay line, then send it back ground interferometer radar after amplifier amplifies.

4. the microdisplacement measurement method based on range gate deception technology according to claim 1, is characterized in that: microwave coherent reflection device adopts digital RF memory technology DRFM to realize postponing.

5. based on a micro-displacement measuring system for range gate deception technology, it is characterized in that: comprise the multiple microwave coherent reflection devices be arranged on testee, away from the hard-wired ground interferometer radar in testee place; Ground interferometer radar is to microwave coherent reflection device radiation radar signal, carry out Late phase ginseng after each microwave coherent reflection device receives signal and be forwarded back to ground interferometer radar again, after ground interferometer radar receives the signal reflected through delay coherent, identify each microwave coherent reflection device, interfere measurement technique is adopted to calculate twice phase differential before and after signal, and by calculating the micrometric displacement amount of each microwave coherent reflection device.

6. the micro-displacement measuring system based on range gate deception technology according to claim 5, is characterized in that: the circuit structure of described microwave coherent reflection device comprises lag line, amplifier, circulator and antenna; After antenna receives signal, signal amplifies after delay line postpones, and sends it back ground interferometer radar again through amplifying signal by antenna.

7. the micro-displacement measuring system based on range gate deception technology according to claim 5, is characterized in that: the circuit structure of described ground interferometer radar comprises dual-mode antenna, Up/Down Conversion channel, signal generator, matched filtering circuit, interferometry module and micrometric displacement Deformation calculation module.