CN103163519A - Ultra wide band imaging semi-physical simulation testing method and system based on digital oscilloscope - Google Patents

Abstract

The invention discloses an ultra wide band imaging semi-physical simulation testing method and an ultra wide band imaging semi-physical simulation testing system based on a digital oscilloscope. The system comprises a testing plate, an oscilloscope and an upper computer, wherein a signal transmitting device, a signal receiving device, a transmitting antenna and a receiving antenna are integrated on the testing plate; a signal source transmits a signal to the signal transmitting device; the signal transmitting device respectively transmits the signal to the transmitting antenna and the signal receiving device; the receiving antenna receives the signal which is transmitted by the transmitting antenna and then reflected back by an object to be tested; the receiving antenna transmits the signal to the signal receiving device; the signal receiving device is connected with the oscilloscope; and the oscilloscope communicates with the upper computer. According to the invention, the manual operation frequency of the oscilloscope is reduced, the abrasion of the oscilloscope is reduced, a new signal processing algorithm and an imaging computing function can be flexibly added, and the analysis testing efficiency of the algorithm and the device is improved.

Description

Ultra broadband imaging half-practicality imitation test method and system based on digital oscilloscope

Technical field

The present invention relates to ultra broadband imaging research field, relate in particular to a kind of ultra broadband imaging half-practicality imitation test method and system based on digital oscilloscope.

Background technology

In the ultra broadband imaging technique is carried out research process, generally various parameters need to be set manually to oscillograph at present, repeatedly oscillograph manually be arranged and easily cause oscillographic wearing and tearing, not utilize oscillographic protection.

Existing oscillograph is built-in with the simple signal processing methods such as filtering, but these methods can't be integrated in test macro, and is difficult to satisfy the demand that ultra-broadband signal is processed.

Prior art not is integrated into signal projector spare, signal receiver spare, emitting antenna and receiving antenna on a test board, and prior art can not realize the change of components and parts on test board flexibly.

Existing test macro only can be checked the reception signal by oscillographic display screen, can't carry out to received signal real-time processing, and oscillograph itself can't carry out complicated imaging calculating to signal, in order to realize the demonstration of image, can only again store signal into host computer by movable storage device and calculate and analyze.

High-resolution imaging for the multi-path echo signal, existing compensated distance method is generally carried out in the image processing links, but the operand of image distance compensation is huge, can affect the speed of imaging, have and compensate the puzzlement that compensation brings to the noise signal mistake in signal, to whole range on target signal compensation, in the amplification target signal, also can greatly amplify near the faint clutter noise of remote target signal, cause the target effective signal to be submerged in the clutter noise interference, it is even worse that the effect after compensation will become.

Summary of the invention

Purpose of the present invention is exactly to provide a kind of ultra broadband imaging half-practicality imitation test method and system based on digital oscilloscope in order to address the above problem, and it has advantages of the analysis efficiency of raising, it is good to wearing and tearing, the imaging effect of instrument to reduce.

To achieve these goals, the present invention adopts following technical scheme:

ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope, comprise test board, oscillograph, host computer, be integrated with signal projector spare on described test board, signal receiver spare, emitting antenna and receiving antenna, signal source is transmitted to signal projector spare with signal, signal projector spare is transferred to respectively emitting antenna and signal receiver spare with signal, the signal that is reflected by determinand after receiving antenna reception transmission antennas transmit, receiving antenna is transferred to signal receiver spare with signal, signal receiver spare is connected with digital oscilloscope, oscillograph is communicated by letter with host computer.

Described signal projector spare is directional coupler.

Described signal receiver spare comprises amplifier, power splitter, low noise amplifier, frequency mixer, the amplifier of signal receiver spare receives the signal of directional coupler, the signal of amplifier is transferred to power splitter, the signal of power splitter is transferred to frequency mixer, the signal that low noise amplifier receives receiving antenna also is transferred to frequency mixer with signal, and the signal that the signal that frequency mixer transmits power splitter and low noise amplifier transmit carries out being transferred to oscillograph after mixing.

Described oscillograph is used for the signal of collecting test partitioned signal receiving device output, carries out the high-precision A/D conversion.

Described oscillograph is connected with host computer by LAN or USB line.

Communicate by VISA communication protocol between described oscillograph and host computer.

The method of testing of said system mainly is divided into following steps:

Step (1): beginning, confirm that at first LAN or USB line have connected host computer and oscillograph; Host computer is confirmed searched the arriving in oscillographic communication protocol address by VISA communication protocol, represents that so far host computer can communicate by letter with oscillograph;

Step (2): open the host computer human interface software, carry out VISA and connect the oscillograph order, determine to connect and complete;

Step (3): oscillographic correlation parameter is set, and described correlation parameter comprises image data length, sampling rate, bandwidth, image data number of times, channel selecting;

Step (4): judge whether success of parameter setting, if arrange successfully host computer shows the signal waveform of the first via, if setup failed then display waveform not carries out wireline inspection according to pointing out queueing problem, is returned to step (3) after queueing problem;

Step (5): the beginning image data, the oscillograph parameter that host computer will arrange sends oscillograph to, and oscillograph is carried out the image data order;

Step (6): oscillograph gathers one group of signal data, preserves;

Step (7): whether the number of times that judges data acquisition reaches the value that has arranged, if just enter step (8); Otherwise return to step (6);

Step (8): the data that reach times of collection are carried out signal successively process, image is processed; After the signal processing finishes, the signal waveform after the host computer display is processed; After the image processing finished, host computer showed the final image that becomes;

Step (9): judge whether to stop to gather, if it is stop gathering, finish; Otherwise return to step (6).

The concrete steps of described step (8) are:

Step (8-1): medium filtering;

Step (8-2): mean filter;

Step (8-3): the time domain door is processed;

Step (8-4): target is extracted, and the signal that adopts the peak-value detection method acquisition to satisfy actual requirement is echo signal;

Step (8-5): range on target signal backoff algorithm;

Step (8-6): finish.

The concrete steps of described step (8-5) are:

Step (8-5-1): determine one apart from critical value μ, effect is just to carry out compensated distance when travel path greater than this critical value, otherwise does not compensate;

Step (8-5-2): the range on target signal compensation formula is:

$Y\left(t\right)=\left\{\begin{array}{cc}{Y}_{\mathrm{org}}\left(t\right)& L\≤\mathrm{\μ}\\ Y_{\mathrm{org}}\left(t\right)*{\left(\frac{L}{\mathrm{\μ}}\right)}^2& L>\mathrm{\μ}\end{array}\right.---\left(1\right)$

In formula: Y _org(t) be not have balanced original signal amplitude;

Y (t) obtains compensated distance signal amplitude afterwards.

L is the travel path that is calculated by moment t corresponding to each signaling point, and computing formula is L=C*t, and C is electromagnetic wave propagation speed.

The current demand signal point is not compensated during less than or equal to critical value μ as L, as L during greater than critical value μ, with the amplitude of current demand signal point multiply by the travel path L of current point and critical value ratio square as new signal amplitude.

During signal compensation, the first automatic lifting number of winning the confidence feature, only carry out compensated distance to echo signal, but not merely according to apart to all signal compensations, avoid clutter noise to be amplified mistakenly.

The concrete steps of described step (8-5-1) are:

Step (8-5-1-1): do not consider the body of wall factor, the relation of target and emitting antenna, receiving antenna satisfies elliptic equation:

$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1---\left(2\right)$

In formula: in search coverage, the coordinate of target is (x, y);

A is half of transverse;

B is half of ellipse short shaft.

Wherein: L=2a, d _i=2c, b ²=a ²-c ², L=L _i+ L ₀

a-c≤L ₀≤a+c（3）

$\frac{L-d_i}{2}\≤L_0\≤\frac{L+d_i}{2}---\left(4\right)$

In formula: then L is reflected back the whole travel path of receiving antenna by target from the emitting antenna to the target;

L ₀It is the emitting antenna range-to-go;

L _i(i=1 ..., be n) target to the distance of i road receiving antenna;

I road receiving antenna is d to the distance of emitting antenna _i

C is half of oval focal length.

Step (8-5-1-2): the received power density formula of i road receiving antenna is:

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{L}_i^2{L}_0^2}---\left(5\right)$

Because L=L _i+ L ₀Can get

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{[-{(L_0-\frac{L}{2})}^2+\frac{L^2}{4}]}^2}---\left(6\right)$

Wherein: P _tIt is the emissive power of emitting antenna; G _tIt is the gain of emitting antenna; G _rIt is the gain of receiving antenna; δ is the sectional area of target scattering.

Step (8-5-1-3): can be obtained by (4) and (6):

$\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{L^4}\≤{\mathrm{\ρ}}_i\≤\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{{(L^2-{d_i}^2)}^2}---\left(7\right)$

The maximal value of definition received power density is:

The minimum value of definition received power density is:

Definition error rate Δ is:

$\mathrm{\Δ}=\frac{{\mathrm{\ρ}}_{\max }-{\mathrm{\ρ}}_{\min }}{{\mathrm{\ρ}}_{\min }}---\left(8\right)$

In the situation that emitting antenna, receiving antenna performance are known, Δ is relevant with L and di.Make μ by way of compensation apart from critical value, as L during μ, Δ is enough little, can think L this moment di, pmax=pmin determines the value of μ accordingly according to the Δ value.

The concrete steps of described step (8-5-2) are:

Step (8-5-2-1): when L＜=μ, do not need compensated distance in the near field;

As L〉during μ, by (5) as can be known the emissive power of emitting antenna be:

$P_t=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2{\mathrm{\ρ}}_i}{G_t{G}_r\mathrm{\δ}}---\left(9\right)$

Definition emissive power coefficient:

$q=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2}{G_t{G}_r\mathrm{\δ}}---\left(10\right)$

Therefore suppose that the travel path of far field any point is L, the ratio of the emissive power coefficient when the emissive power coefficient of any point is μ with travel path is:

$Q_p=\frac{q_L}{q_{\mathrm{\μ}}}=\frac{{L_i}^2{L_0}^2}{{{\mathrm{\μ}}_i}^2{{\mathrm{\μ}}_0}^2}---\left(11\right)$

In formula: μ _iBe when travel path is μ target to the distance of i road receiving antenna,

μ ₀It is emitting antenna range-to-go when travel path is μ.

Step (8-5-2-2):

According to the relation of signal power and signal amplitude as can be known, the far field any point with the ratio that travel path is the Amplitude Compensation coefficient of μ time point is:

$Q_U=\frac{L_i{L}_0}{{\mathrm{\μ}}_i{\mathrm{\μ}}_0}---\left(12\right)$

Because of far field any point L〉μ, so Δ is enough little, can think L this moment〉di, can obtain:

$L_0=L_i=\frac{L}{2}$

${\mathrm{\μ}}_0={\mathrm{\μ}}_i=\frac{\mathrm{\μ}}{2}$

Therefore penalty coefficient is

$Q_U=\frac{{\left(\frac{L}{2}\right)}^2}{{\left(\frac{\mathrm{\μ}}{2}\right)}^2}={\left(\frac{L}{\mathrm{\μ}}\right)}^2---\left(13\right)$

The formula that finally obtains signal is carried out compensated distance is:

$Y\left(t\right)=\left\{\begin{array}{cc}{Y}_{\mathrm{org}}\left(t\right)& L\≤\mathrm{\μ}\\ Y_{\mathrm{org}}\left(t\right)*{\left(\frac{L}{\mathrm{\μ}}\right)}^2& L>\mathrm{\μ}\end{array}\right.---\left(1\right)$

Principle of work of the present invention:

Transmitting to penetrate runs into object after wall or barrier can reflect, and is received by receiving antenna after again penetrating wall, penetrates wall and causes the echo signal strength retrogression very large for twice.The decay far away of object or obstacle distance antenna is larger, and object reflection of electromagnetic wave characteristic is more weak, and echo signal intensity also can be more weak.Become large problem in order to overcome echo signal along with distance increases decay, usually need to carry out compensated distance by each pixel to search coverage far and near according to distance when image is processed.For the high-resolution imaging of multi-path echo signal, when carrying out compensated distance in image is processed, operand can be very large.Therefore the angle of processing from signal proposes to solve echo signal with becoming large problem apart from becoming far to decay, and is chosen in and carries out compensated distance in echoed signal.

Beneficial effect of the present invention:

1. the present invention is applied in the ultra broadband echoed signal and analyzes and the research aspect, can improve analysis efficiency, reduces oscillographic manual operation number of times, thereby slows down wearing and tearing to instrument, has realized safeguarding oscillographic effect; Both can realize setting and signals collecting to the oscillograph parameter by host computer, and realize again Signal online analysis and real time imagery are shown.Avoided repeatedly regulating the trouble of oscillograph button, display mode is more effectively directly perceived.

2. the present invention is by being integrated into directional coupler, amplifier, power splitter, LNA, frequency mixer, emitting antenna, receiving antenna on a test board, filled up the blank in this field in the prior art, just can realize transmitting and receiving of signal by a test board, solve traditional modules and independently disperseed to be difficult for the problem of unified management, also provide an integrated platform for the semi-hardware type simulation test system.

3. the present invention can be applied in ultra broadband imaging research field, connects oscillograph and host computer by LAN/USB, oscillographic input port connecting test plate, thus form a complete semi-matter simulating system; Can change device in test board, the device that different model is dissimilar is tested, can obtain fast test result, facilitate the research and analysis of ultra broadband imaging.

4. the present invention can be applied in ultra broadband imaging research field, can add various signals according to actual needs and process and image processing method, the signal that emulation testing proposes in nearly actual environment and the quality of image processing method.The deviation of having avoided pure emulation link to occur has strengthened practicality and the robustness of method, thereby can shorten research cycle, increases work efficiency.

5. by carrying out compensated distance in the signal processing links of echoed signal, but not each pixel is carried out the mode of compensated distance in the imaging processing link, the operand when greatly reducing compensation.And first extract the concept of signal characteristic when having introduced signal compensation, only echo signal is carried out compensated distance, but not merely according to distance to all signal compensations, avoided clutter noise to be amplified mistakenly; Set a distance threshold in the range on target signal compensation method, the echo signal that only reaches distance threshold just can be carried out compensated distance, the problem of having avoided the nearer target of range transmission antenna blindly to be amplified.

Description of drawings

Fig. 1 is system chart of the present invention;

Fig. 2 is workflow diagram of the present invention;

Fig. 3 is detection model of the present invention;

Fig. 4 is signal distance compensation contrast legend of the present invention;

Fig. 5 is the signal of not processing through signal;

Fig. 6 is the Data Comparison schematic diagram after signal is processed rear real data and target extraction;

Fig. 7 is the Data Comparison schematic diagram after the data after target is extracted compensate with range on target signal.

Embodiment:

The invention will be further described below in conjunction with accompanying drawing and embodiment.

As shown in Figure 1, ultra-broadband signal source emission ultra broadband bandwidth signal, after penetrating barrier (wall, rubble, ruins etc.), running into object can reflect, reflected signal sees through barrier and is received by four road receiving antennas, oscillographic four passages connect respectively four road receiving antennas passage at place separately, and oscillograph can show in real time to this four tunnel receptions signal data.

The device detection plate portion comprises signal projector spare, emitting antenna, receiving antenna and signal receiver spare.Wherein signal projector spare is directional coupler, and signal receiver spare comprises amplifier, power splitter, LNA, frequency mixer.Each device on test board can be changed, in order to the performance of test component.

Utilize host computer to use VISA communication protocol, the mode by LAN or USB line is connected with oscillograph and communicates.

The man-machine interface of host computer MATLAB software programming is divided into parameter setting area, control area, viewing area on the interface.Can complete in the parameter setting area oscillographic image data length, sampling rate, bandwidth, image data number of times, the isoparametric setting of channel selecting; The control area comprises and connects the oscillograph button, begins to gather, finishes the function such as collection; The viewing area can show in real time the signal after processing through signal in the territory, cue field, in image display area, the imaging results after processing through image is shown in real time.

Fig. 2 is the workflow that MATLAB realizes the ultra broadband imaging, can complete oscillographic parameter setting, also can gather oscillographic four road signal datas, to signal data executive signal disposal route, and calculate image, can select the mode of two peacekeeping person's three-dimensionals to be presented in imaging region.

The method of testing of said system mainly is divided into following steps:

Step (1): beginning, confirm that at first LAN or USB line have connected host computer and oscillograph; Host computer is confirmed searched the arriving in oscillographic communication protocol address by VISA communication protocol, represents that so far host computer can communicate by letter with oscillograph;

Step (2): open the host computer human interface software, carry out VISA and connect the oscillograph order, determine to connect and complete;

Step (3): oscillographic correlation parameter is set, and described correlation parameter comprises image data length, sampling rate, bandwidth, image data number of times, channel selecting;

Step (4): judge whether success of parameter setting, if arrange successfully host computer shows the signal waveform of the first via, if setup failed then display waveform not carries out wireline inspection according to pointing out queueing problem, is returned to step (3) after queueing problem;

Step (5): the beginning image data, the oscillograph parameter that host computer will arrange sends oscillograph to, and oscillograph is carried out the image data order;

Step (6): oscillograph gathers one group of signal data, preserves;

Step (7): whether the number of times that judges data acquisition reaches the value that has arranged, if just enter step (8); Otherwise return to step (6);

Step (8): the data that reach times of collection are carried out signal processing and image processing successively.After the signal processing finishes, the signal waveform after the host computer display is processed; After the image processing finished, host computer showed the final image that becomes;

Step (9): judge whether to stop to gather, if it is stop gathering, finish; Otherwise return to step (6).

As shown in Figure 3, the data of collection have the N group altogether, at first N group data are carried out medium filtering, then carry out mean filter and obtain one group of data; Carry out afterwards time domain door intercept signal, namely according to the actual detection zone, signal data is intercepted, the signal data of non-search coverage can be removed, and only keeps the signal data in search coverage; Signal after intercepting is carried out target extract, the signal that adopts peak-value detection method acquisition peak value to satisfy actual requirement is echo signal, and so far signal only keeps echo signal; Echo signal is carried out compensated distance; Afterwards signal is carried out imaging and calculate, obtain view data.

As shown in the model through walls that Fig. 4 has simplified, target is in certain position of body of wall one side, and the opposite side of body of wall is emitting antenna and receiving antenna, wherein for convenience of description, only used a receiving antenna to explain.The transmission antennas transmit electromagnetic wave signal, passing the target that body of wall is detected in the zone reflects, the receiving antenna of body of wall opposite side receives echoed signal, whole process is a complete travel path, do not consider the body of wall factor, the relation of target and emitting antenna, receiving antenna satisfies elliptic equation:

$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1---\left(2\right)$

In formula: in search coverage, the coordinate of target is (x, y);

A is half of transverse;

B is half of ellipse short shaft.

Wherein: L=2a, d _i=2c, b ²=a ²-c ², L=L _i+ L ₀

a-c≤L ₀≤a+c（3）

$\frac{L-d_i}{2}\≤L_0\≤\frac{L+d_i}{2}---\left(4\right)$

In formula: then L is reflected back the whole travel path of receiving antenna by target from the emitting antenna to the target;

L ₀It is the emitting antenna range-to-go;

L _i(i=1 ..., be n) target to the distance of i road receiving antenna;

I road receiving antenna is d to the distance of emitting antenna _i

C is half of oval focal length.

The received power density formula of i road receiving antenna is:

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{L}_i^2{L}_0^2}---\left(5\right)$

Because L=L _i+ L ₀Can get

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{[-{(L_0-\frac{L}{2})}^2+\frac{L^2}{4}]}^2}---\left(6\right)$

Wherein: P _tIt is the emissive power of emitting antenna; G _tIt is the gain of emitting antenna; G _rIt is the gain of receiving antenna; δ is the sectional area of target scattering.

Can be obtained by (4) and (6):

$\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{L^4}\≤{\mathrm{\ρ}}_i\≤\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{{(L^2-{d_i}^2)}^2}---\left(7\right)$

The maximal value of definition received power density is:

The minimum value of definition received power density is:

Definition error rate Δ is:

$\mathrm{\Δ}=\frac{{\mathrm{\ρ}}_{\max }-{\mathrm{\ρ}}_{\min }}{{\mathrm{\ρ}}_{\min }}---\left(8\right)$

In the situation that emitting antenna, receiving antenna performance are known, Δ is relevant with L and di.Make μ by way of compensation apart from critical value, as L during μ, Δ is enough little, can think L this moment di, pmax=pmin determines the value of μ accordingly according to the Δ value.

When L＜=μ, do not need compensated distance in the near field;

As L〉during μ, by (5) as can be known the emissive power of emitting antenna be:

$P_t=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2{\mathrm{\ρ}}_i}{G_t{G}_r\mathrm{\δ}}---\left(9\right)$

Definition emissive power coefficient:

$q=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2}{G_t{G}_r\mathrm{\δ}}---\left(10\right)$

Therefore suppose that the travel path of far field any point is L, the ratio of the emissive power coefficient when the emissive power coefficient of any point is μ with travel path is::

$Q_p=\frac{q_L}{q_{\mathrm{\μ}}}=\frac{{L_i}^2{L_0}^2}{{{\mathrm{\μ}}_i}^2{{\mathrm{\μ}}_0}^2}---\left(11\right)$

In formula: μ _iBe when travel path is μ target to the distance of i road receiving antenna,

μ ₀It is emitting antenna range-to-go when travel path is μ.

According to the relation of signal power and signal amplitude as can be known, the ratio of the Amplitude Compensation coefficient when the far field any point is μ with travel path is:

$Q_U=\frac{L_i{L}_0}{{\mathrm{\μ}}_i{\mathrm{\μ}}_0}---\left(12\right)$

Because of far field any point L〉μ, so Δ is enough little, can think L this moment〉di, can obtain:

$L_0=L_i=\frac{L}{2}$

${\mathrm{\μ}}_0={\mathrm{\μ}}_i=\frac{\mathrm{\μ}}{2}$

Therefore penalty coefficient is

$Q_U=\frac{{\left(\frac{L}{2}\right)}^2}{{\left(\frac{\mathrm{\μ}}{2}\right)}^2}={\left(\frac{L}{\mathrm{\μ}}\right)}^2---\left(13\right)$

The formula that finally obtains signal is carried out compensated distance is:

$Y\left(t\right)=\left\{\begin{array}{cc}{Y}_{\mathrm{org}}\left(t\right)& L\≤\mathrm{\μ}\\ Y_{\mathrm{org}}\left(t\right)*{\left(\frac{L}{\mathrm{\μ}}\right)}^2& L>\mathrm{\μ}\end{array}\right.---\left(1\right)$

In formula: Y _org(t) be not have balanced original signal amplitude;

Y (t) obtains compensated distance signal amplitude afterwards.

L is the travel path that is calculated by moment t corresponding to each signaling point, and computing formula is L=C*t, and C is electromagnetic wave propagation speed.

The current demand signal point is not compensated during less than or equal to critical value μ as L, as L during greater than critical value μ, with the amplitude of current demand signal point multiply by the travel path L of current point and critical value ratio square as new signal amplitude.

By only carrying out the mode of compensated distance for echo signal, the negative interaction of clutter reduction noise when compensation.Realize only echo signal being compensated, prerequisite is to identify or to extract echo signal.Be the clutter reduction noise on the one hand, find its feature, source, remove targetedly clutter noise, improve the signal to noise ratio signal to noise ratio (S/N ratio) of echoed signal; That directly feature extraction goes out echo signal according to echo signal on the other hand, the signal characteristic that the object reflection of difformity material obtains is different, whether the motion of object also can present with different signal forms, by the characteristic rule of further investigation echo signal, the accurate extraction of realize target signal.

By carrying out compensated distance in echoed signal, but not when imaging, each pixel is carried out compensated distance, the operand when greatly reducing compensation.During signal compensation, the first automatic lifting number of winning the confidence feature, only carry out compensated distance to echo signal, but not merely according to apart to all signal compensations, avoided clutter noise to be amplified mistakenly.

Transmitting to penetrate runs into object after barrier and can reflect, and is received by receiving antenna after again penetrating barrier, penetrates barrier and causes the echo signal strength retrogression very large for twice.The decay far away of object or obstacle distance antenna is larger, and object reflection of electromagnetic wave characteristic is more weak, and echo signal intensity also can be more weak.

Become large problem in order to overcome echo signal along with distance increases decay, usually need to far and nearly according to distance look like to carry out compensated distance to target when imaging is calculated.But it is very large to carry out the compensated distance operand in imaging computation process.Take the imaging region of 5m*5m as example, be 1cm if require resolution, image has 250,000 points and forms.As shown in Figure 1, have four road receiving antennas, need to carry out compensated distance to 1,000,000 points so altogether and calculate, as seen calculated amount is huge.The distance and position information of target not only is reflected on image, also be reflected on signal data, if can reach the purpose of reduction operand in the enterprising row distance compensation of signal data, if signal data length is 5000 points, No. four antennas only need to carry out compensated distance to 20,000 points and calculate just passable so.

If but to the method for all signal data performance objective signal distance compensation, the clutter in signal, noise also can be exaggerated, and can make on the contrary signal to noise ratio (S/N ratio) even worse after compensated distance, therefore propose the compensated distance method for echo signal.The first automatic lifting number of winning the confidence feature during signal compensation is extracted by target echo signal is extracted, and only echo signal is carried out compensated distance, but not merely according to apart to all signal compensations, has avoided clutter noise to be amplified mistakenly.

As shown in Figure 5, be the signal waveform of not processing through signal, can find out that the barrier impact is larger, reflected signal strength is the strongest, and clutter and interference are also a lot, the position that can't tell echo signal.

As shown in Figure 6, after the methods such as medium filtering, mean filter, time domain door are processed, obtain block curve in figure, the curve representative that dotted line is delineated is through the signal data after target detection, on the magnitude of signal amplitude, the intensity of echo signal very a little less than.

As shown in Figure 7, it is the contrast of signal before signal and the compensation after the compensation that obtains of the compensation method according to formula (1), wherein block curve represents the signal after original process target detection, signal after the curve representative that dotted line is delineated compensates through range on target signal, can find out, after signal compensation, echo signal intensity strengthens greatly.

Although above-mentionedly by reference to the accompanying drawings the specific embodiment of the present invention is described; but be not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various modifications that creative work can make or distortion still in protection scope of the present invention.

Claims (10)

1. based on the ultra broadband imaging semi-hardware type simulation test system of digital oscilloscope, it is characterized in that, comprise test board, oscillograph, host computer, be integrated with signal projector spare on described test board, signal receiver spare, emitting antenna and receiving antenna, signal source is transmitted to signal projector spare with signal, signal projector spare is transferred to respectively emitting antenna and signal receiver spare with signal, the signal that is reflected by determinand after receiving antenna reception transmission antennas transmit, receiving antenna is transferred to signal receiver spare with signal, signal receiver spare is connected with digital oscilloscope, oscillograph is communicated by letter with host computer.

2. the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 1, is characterized in that, described signal projector spare is directional coupler.

3. the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 1, it is characterized in that, described signal receiver spare comprises amplifier, power splitter, low noise amplifier, frequency mixer, the amplifier of signal receiver spare receives the signal of directional coupler, the signal of amplifier is transferred to power splitter, the signal of power splitter is transferred to frequency mixer, low noise amplifier receives the signal of receiving antenna and signal is transferred to frequency mixer, the signal that the signal that frequency mixer transmits power splitter and low noise amplifier transmit carries out being transferred to oscillograph after mixing.

4. the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 1, is characterized in that, described oscillograph is used for the signal of collecting test partitioned signal receiving device output, carries out the high-precision A/D conversion.

5. the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 1, is characterized in that, described oscillograph is connected with host computer by LAN or USB line, communicates by VISA communication protocol between described oscillograph and host computer.

6. the method for testing of above-mentioned arbitrary claim described ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope, is characterized in that, mainly is divided into following steps:

Step (1): beginning, confirm that at first LAN or USB line have connected host computer and oscillograph; Host computer is confirmed searched the arriving in oscillographic communication protocol address by VISA communication protocol, represents that so far host computer can communicate by letter with oscillograph;

Step (2): open the host computer human interface software, carry out VISA and connect the oscillograph order, determine to connect and complete;

Step (3): oscillographic correlation parameter is set, and described correlation parameter comprises image data length, sampling rate, bandwidth, image data number of times, channel selecting;

Step (4): judge whether success of parameter setting, if arrange successfully host computer shows the signal waveform of the first via, if setup failed then display waveform not carries out wireline inspection according to pointing out queueing problem, is returned to step (3) after queueing problem;

Step (5): the beginning image data, the oscillograph parameter that host computer will arrange sends oscillograph to, and oscillograph is carried out the image data order;

Step (6): oscillograph gathers one group of signal data, preserves;

Step (7): whether the number of times that judges data acquisition reaches the value that has arranged, if just enter step (8); Otherwise return to step (6);

Step (8): the data that reach times of collection are carried out signal successively process, image is processed; After the signal processing finishes, the signal waveform after the host computer display is processed; After the image processing finished, host computer showed the final image that becomes;

Step (9): judge whether to stop to gather, if it is stop gathering, finish; Otherwise return to step (6).

7. the method for testing of the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 6, is characterized in that, the concrete steps of described step (8) are:

Step (8-1): medium filtering;

Step (8-2): mean filter;

Step (8-3): the time domain door is processed;

Step (8-4): target is extracted, and the signal that adopts the peak-value detection method acquisition to satisfy actual requirement is echo signal;

Step (8-5): signal distance backoff algorithm;

Step (8-6): finish.

8. the method for testing of the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 7, is characterized in that, the concrete steps of described step (8-5) are:

Step (8-5-1): determine one apart from critical value μ, when travel path just carries out compensated distance greater than this critical value, otherwise do not compensate;

Step (8-5-2): the range on target signal compensation formula is:

$Y\left(t\right)=\left\{\begin{array}{cc}{Y}_{\mathrm{org}}\left(t\right)& L\≤\mathrm{\μ}\\ Y_{\mathrm{org}}\left(t\right)*{\left(\frac{L}{\mathrm{\μ}}\right)}^2& L>\mathrm{\μ}\end{array}\right.---\left(1\right)$

In formula: Y _org(t) be not have balanced original signal range value;

Y (t) obtains compensated distance signal amplitude value afterwards;

L is the travel path that is calculated by moment t corresponding to each signaling point, and computing formula is L=C*t, and C is electromagnetic wave propagation speed;

The current demand signal point is not compensated during less than or equal to critical value μ as L, as L during greater than critical value μ, with the amplitude of current demand signal point multiply by the travel path L of current point and critical value ratio square as new signal amplitude;

During signal compensation, the first automatic lifting number of winning the confidence feature, only carry out compensated distance to echo signal, but not merely according to apart to all signal compensations, avoid clutter noise to be amplified mistakenly.

9. the method for testing of the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 8, is characterized in that, the concrete steps of described step (8-5-1) are:

Step (8-5-1-1): do not consider the body of wall factor, the relation of target and emitting antenna, receiving antenna satisfies elliptic equation:

$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1---\left(2\right)$

In formula: in search coverage, the coordinate of target is (x, y);

A is half of transverse;

B is half of ellipse short shaft;

Wherein: L=2a, d _i=2c, b ²=a ²-c ², L=L _i+ L ₀

a-c≤L ₀≤a+c（3）

$\frac{L-d_i}{2}\≤L_0\≤\frac{L+d_i}{2}---\left(4\right)$

In formula: then L is reflected back the whole travel path of receiving antenna by target from the emitting antenna to the target;

L ₀It is the emitting antenna range-to-go;

L _iWherein, i=1 ..., n is target to the distance of i road receiving antenna;

I road receiving antenna is d to the distance of emitting antenna _i

C is half of oval focal length;

Step (8-5-1-2): the received power density formula of i road receiving antenna is:

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{L}_i^2{L}_0^2}---\left(5\right)$

Because L=L _i+ L ₀

${\mathrm{\ρ}}_i=\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2{[-{(L_0-\frac{L}{2})}^2+\frac{L^2}{4}]}^2}---\left(6\right)$

Wherein: P _tIt is the emissive power of emitting antenna; G _tIt is the gain of emitting antenna; G _rIt is the gain of receiving antenna; δ is the sectional area of target scattering;

Step (8-5-1-3): obtained by (4) and (6):

$\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{L^4}\≤{\mathrm{\ρ}}_i\≤\frac{P_t{G}_t{G}_r\mathrm{\δ}}{{\left(4\mathrm{\π}\right)}^2}*\frac{16}{{(L^2-{d_i}^2)}^2}---\left(7\right)$

The maximal value of definition received power density is:

The minimum value of definition received power density is:

Definition error rate Δ is:

$\mathrm{\Δ}=\frac{{\mathrm{\ρ}}_{\max }-{\mathrm{\ρ}}_{\min }}{{\mathrm{\ρ}}_{\min }}---\left(8\right)$

In the situation that emitting antenna, receiving antenna performance are known, Δ is relevant with L and di; Make μ by way of compensation apart from critical value, as L during μ, Δ is enough little, can think L this moment di, pmax=pmin determines the value of μ accordingly according to the Δ value.

10. the method for testing of the ultra broadband imaging semi-hardware type simulation test system based on digital oscilloscope as claimed in claim 8, is characterized in that, the concrete steps of described step (8-5-2) are:

Step (8-5-2-1): when L＜=μ, do not need compensated distance in the near field;

As L〉during μ, known that by (5) emissive power of emitting antenna is:

$P_t=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2{\mathrm{\ρ}}_i}{G_t{G}_r\mathrm{\δ}}---\left(9\right)$

Definition emissive power coefficient:

$q=\frac{{\left(4\mathrm{\π}\right)}^2{L_i}^2{L_0}^2}{G_t{G}_r\mathrm{\δ}}---\left(10\right)$

Therefore suppose that the travel path of far field any point is L, the ratio of the emissive power coefficient when the emissive power coefficient of any point is μ with travel path is:

$Q_p=\frac{q_L}{q_{\mathrm{\μ}}}=\frac{{L_i}^2{L_0}^2}{{{\mathrm{\μ}}_i}^2{{\mathrm{\μ}}_0}^2}---\left(11\right)$

In formula: μ _iBe when travel path is μ target to the distance of i road receiving antenna,

μ ₀It is emitting antenna range-to-go when travel path is μ;

Step (8-5-2-2):

Know according to the relation of signal power and signal amplitude, the ratio of the Amplitude Compensation coefficient when the far field any point is μ with travel path is:

$Q_U=\frac{L_i{L}_0}{{\mathrm{\μ}}_i{\mathrm{\μ}}_0}---\left(12\right)$

Because of far field any point L〉μ, so Δ is enough little, can think L this moment〉di, obtain:

$L_0=L_i=\frac{L}{2}$

${\mathrm{\μ}}_0={\mathrm{\μ}}_i=\frac{\mathrm{\μ}}{2}$

Therefore penalty coefficient is

$Q_U=\frac{{\left(\frac{L}{2}\right)}^2}{{\left(\frac{\mathrm{\μ}}{2}\right)}^2}={\left(\frac{L}{\mathrm{\μ}}\right)}^2---\left(13\right)$

The formula that finally obtains signal is carried out compensated distance is:

$Y\left(t\right)=\left\{\begin{array}{cc}{Y}_{\mathrm{org}}\left(t\right)& L\≤\mathrm{\μ}\\ Y_{\mathrm{org}}\left(t\right)*{\left(\frac{L}{\mathrm{\μ}}\right)}^2& L>\mathrm{\μ}\end{array}\right.---\left(1\right).$

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