CN105487056A - S-wave band Doppler radar breaking wave interference suppression method and device - Google Patents

Abstract

The invention discloses an S-wave band Doppler radar breaking wave interference suppression method and device and belongs to the radar signal processing field. According to the S-wave band Doppler radar breaking wave interference suppression method and device of the invention, based on original S-wave band Doppler radar signal processing, an empirical mode decomposition method is adopted to decompose breaking wave interfered radar echo signals into a plurality of intrinsic mode functions; and based on a characteristic that the frequency of breaking wave signals is high relative to general sea echo signals, components with high frequency are removed from all the intrinsic mode functions, and the other intrinsic mode functions are reconstructed, so that breaking wave suppressed signals can be obtained. When the method and device of the invention are used for actual data processing, the application effects of the method and device are excellent, and useful signals are not damaged when breaking wave interference is suppressed, and processing effects are obvious, and radar detection precision can be improved.

Description

A kind of method and apparatus of S-band radar Doppler breaker AF panel

Technical field

The present invention relates to radar signal processing field, be related specifically to a kind of method and apparatus of S-band radar Doppler breaker AF panel.

Background technology

Wave is a kind of sea phenomenon that sea water particle dipping and heaving is formed, and effective measurement of wave prevents all important in inhibitings to coastal engineering construction, exploration of ocean resources and Oceanic disasters.Microwave Doppler radar is little with its environmental interference, measuring accuracy is high, lightweight and portable in volume, can accurately reflect the advantages such as the details of Sea level changes, expand extra large state measurement means, improve the ability of marine monitoring, have important value to extra large state Real-Time Monitoring and scientific research of seas.

When ocean stormy waves is larger, often there is Fragmentation Phenomena in sea surface wave, sea water particle motion speed, depart from the spray that surface, sea forms white, the situation of this Wave Breaking has interference clearly for microwave Doppler radar return, have impact on the quality of data of radar return greatly, cause the sea radial velocity in follow-up radar refutation process and ocean wave parameter inversion result to occur error, have impact on the measuring accuracy of radar.

Breaker interference mainly contains following characteristic: in the process that (1) fragmentation is formed, and wave steepening, the Radar Cross Section of wave increases, and echoed signal energy strengthens.(2) during broken generation, breaker is superimposed upon on general wave, and crest water particle motion speed obviously becomes large, is doped with breaker interference in radar return, and radar return doppler spectral centre frequency shift becomes large, bandwidth broadens, energy grow.

The method of existing microwave Doppler radar process breaker interference, that the centre frequency of breaker interfering data doppler spectral is extracted as singular point from the frequency sequence of a period of time, then the frequency values of relevant position is given up, the data being equivalent to breaker interference are disallowable, there is the data vacancy in moment in breaker, precision radar being extracted to extra large state parameter can produce very large impact.

Summary of the invention

The present invention is directed to the problems referred to above, a kind of method and apparatus of S-band radar Doppler breaker AF panel is proposed, avoid existing breaker disposal route to the adverse effect of radar inversion accuracy, the present invention is complete reservation useful signal while the interference of reduction breaker, for existing microwave Doppler radar system provides a kind of effective suppression breaker interference method, thus radar detection precision can be improved.

A method for S-band radar Doppler breaker AF panel, comprises the following steps:

Step 1, obtains one group of radar return FT1 data, carries out pre-service, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the position of the distance element of each frame data breaker according to energy and centre frequency;

Step 2, gets the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, described bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

Step 3, gets the data of first distance element in this frame FT1 data, determines whether breaker interfering data according to the result of step 1; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward step 8 to;

Step 4, by doppler spectral translation, makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data to the doppler spectral after translation;

Step 5, the FT1 data new to this distance element carry out empirical mode decomposition EMD, obtain a two or more intrinsic mode function IMF and trend function r _n(t);

Step 6, removes the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Step 7, judge described bandwidth whether within the scope of bandwidth threshold, if so, then these data are the data after breaker process; If described band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to removing the data of IMF1, the data of reconstructed residual are the data after breaker process;

Step 8, whether the data judging when pre-treatment are the data of last distance element, if not, then whether get the data of next distance element, forward step 3 to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

Wherein, the FT1 data in described step 1 are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

Wherein, in described step 5, the step of empirical mode decomposition EMD is as follows,

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero; So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 2., 4. () repeat step, calculate the 3rd mode C ₃(t);

6. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural intrinsic mode function IMF and trend function r _n(t).

A device for S-band radar Doppler breaker AF panel, comprising:

Breaker distance element position acquisition unit, for obtaining one group of radar return FT1 data, carry out pre-service, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the position of the distance element of each frame data breaker according to energy and centre frequency;

Bandwidth threshold scope acquiring unit, for getting the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, described bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

First judging unit, for getting the data of first distance element in this frame FT1 data, the result according to breaker distance position acquisition unit determines whether breaker interfering data; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward the 3rd judging unit to;

Doppler spectral processing unit, for by doppler spectral translation, makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data to the doppler spectral after translation;

EMD processing unit, carries out empirical mode decomposition EMD for the FT1 data new to this distance element, obtains a two or more intrinsic mode function IMF and trend function r _n(t);

High fdrequency component removal unit, for removing the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Second judging unit, for judging described bandwidth whether within the scope of bandwidth threshold, if so, then these data are the data after breaker process; If described band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to removing the data of IMF1, the data of reconstructed residual are the data after breaker process;

3rd judging unit, whether the data for judging when pre-treatment are the data of last distance element, if not, then get the data of next distance element, whether forward the first judging unit to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

Wherein, the FT1 data in described breaker distance element position acquisition unit are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

Wherein, in described EMD processing unit, the step of empirical mode decomposition EMD is as follows,

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero; So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 3., 4. () repeat step, calculate the 3rd mode C ₃(t);

7. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural intrinsic mode function IMF and trend function r _n(t).

The invention has the advantages that:

1. before doing EMD process, translation is carried out to doppler spectral, can effectively decompose breaker signal and can not useful signal be affected when doppler spectral is positioned at x-axis positive axis.

2. in microwave Doppler radar, have employed the interference of EMD algorithm process breaker, by EMD, radar return data are decomposited different IMF by frequency height, by breaker signal and general sea echo Signal separator, thus while the interference of suppression breaker, farthest remain useful signal feature.

3.EMD algorithm is a kind of adaptive spatio-temporal filtering method, according to the feature of signal by the component being decomposed into different frequency of signal adaptive, exist in the radar echo signal of breaker interference and contain breaker component and general sea echo component, both all have respective feature, so both can well be separated by EMD algorithm.

4. breaker is high fdrequency component relative to general sea echo, in the decomposition result of EMD algorithm, judges to need to reject several high-frequency I MF component by doppler spectral bandwidth, reconstructs all the other component can completelys and recovers the data after rejecting breaker interference.

5. the data of pair breaker interference process instead of directly give up, and complete remains useful data, effectively raises the accuracy of the follow-up extra large state parametric inversion of radar.

The present invention proposes a kind of novel S-band microwave Doppler radar breaker disturbance restraining method by above innovative point, the method is in real data process, and effect is fine, lossless signal while suppression breaker, obvious processing effect, improves radar wave detection accuracy.

Accompanying drawing explanation

Fig. 1: the radar system surveillance map of sea condition when generalized case provided by the invention and breaker occur;

Fig. 2: generalized case provided by the invention and radar return doppler spectral when occurring broken compare;

Fig. 3: the method flow diagram of a kind of S-band radar Doppler breaker AF panel provided by the invention;

Fig. 4: empirical mode decomposition EMD processing flow chart provided by the invention;

Fig. 5: the doppler spectral before and after breaker interfering data provided by the invention process;

Fig. 6: the centre frequency of trying to achieve before and after a certain distance element data processing breaker interference in actual ghosts data provided by the invention and energy sequence contrast;

Fig. 7: the structural representation of the device of a kind of S-band radar Doppler breaker AF panel provided by the invention.

Embodiment

Below with instantiation by reference to the accompanying drawings, the invention will be further described.

Embodiment 1:

Microwave Doppler radar is by antenna transmission electromagnetic wave irradiation detection sea, according to wave blending surface scattering theory and linear wave theory, contain marine information in ocean surface scatter echo, radar is by obtaining extra large state parameter to a series of inversion algorithms of marine echo data.

As shown in Figure 1, sea condition when a-quadrant is breaker generation, B region is generalized case.The echo power that radar receives can be expressed as

$P_r=\frac{P_t{\mathrm{GA}}_e\mathrm{\σ}}{{\left(4\mathrm{\π}\right)}^2{R}^4}---\left(1\right)$

Wherein, P _trepresent radar transmission power, R represents radar range, and G represents antenna gain, A _erepresent antenna capture area, σ represents Radar Cross Section.

When wave breaking, wave steepening, the radar cross section of incident electromagnetic wave becomes large, thus doppler spectral energy is strengthened, and in the process of fragmentation, crest water particle speed increases, and causes doppler spectral centre frequency and bandwidth all to become large.As shown in Figure 2, doppler spectral when occurring broken can be considered as the superposition of the doppler spectral of doppler spectral generally and breaker component.

The present invention utilizes the characteristic of Echo Doppler Spectra when occurring broken, utilizes the feature of EMD method adaptive decomposition signal to process the data that breaker disturbs, eliminates the interference of breaker, farthest remain useful signal.Concrete implementation step is see Fig. 3:

Step 1, obtain one group of radar return FT1 data, comprise the data of a period of time all distance elements, pre-service is carried out to these group data, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the distance element position of each frame data breaker according to energy and centre frequency;

In this step, carry out breaker detection according to breaker doppler spectral energy and the larger feature of centre frequency, obtain the position that each moment, the distance element of breaker occurred.

Step 2, gets the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

For subsequent step, bandwidth threshold scope judges that the front several IMF component of removal provides foundation, when the data doppler spectral bandwidth after processing is in threshold range, represent that process completes.

Step 3, gets the data of first distance element in this frame FT1 data, determines whether breaker interfering data according to the result of step 1; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward step 8 to;

Ask doppler spectral centre frequency and bandwidth left and right endpoint location can know the frequency range at doppler spectral place, judge whether to need translation doppler spectral to suitable position with this.

Step 4, translation doppler spectral makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data corresponding to the doppler spectral after translation to the doppler spectral after translation;

When current direction is away from seashore, the doppler spectral of useful signal is in the positive axis of x-axis, and breaker causes doppler spectral bandwidth to be widened to x-axis positive axis.When current direction is towards seashore, if current speed is comparatively large and occur broken, then doppler spectral entirety is positioned at x-axis positive axis HFS.Under both of these case, if do not carry out doppler spectral translation, then may include useful signal in the high fdrequency component that EMD decomposes, so will doppler spectral translation be carried out, guarantee that useful signal can not be removed.

Step 5, to exist breaker interference step 4 described in new FT1 data carry out empirical mode decomposition EMD, obtain a two or more intrinsic mode function IMF and trend function r _n(t);

The step of empirical mode decomposition EMD is as follows, and flow process is as Fig. 4:

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero.So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 3., 4. () repeat step, calculate the 3rd mode C ₃(t);

7. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural IMF and trend function r _n(t).

Step 6, removes the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Because breaker component is positioned at HFS in doppler spectral, so when processing FT1 data, carry out breaker suppression process by removing high fdrequency component, removal high fdrequency component reconstructs all the other components and can remove the interference of breaker and retain useful signal.

Step 7, judges that within the scope of the bandwidth threshold of bandwidth whether described in step 1, if so, then these data are the data after breaker process; If band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to the data removing IMF1, the data of reconstructed residual are the data after breaker process.

By judging in bandwidth threshold scope, whether the data doppler spectral bandwidth after processing determines whether process completes, when the data doppler spectral bandwidth removing IMF1 is still greater than the maximal value of bandwidth threshold scope, represent that breaker component is not completely removed, guarantee effectively to suppress breaker to disturb so will continue to remove IMF2.

Step 8, whether the data judging when pre-treatment are the data of last distance element, if not, then whether get the data of next distance element, forward step 3 to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

To suppress breaker interference after data ask doppler spectral just can be inhibited breaker interference doppler spectral, as shown in Figure 5, doppler spectral after process is compared with before process, and energy, bandwidth sum centre frequency reduce all to some extent, and the complete effective doppler information remaining wave.

The interference of process breaker obtains correct doppler spectral, thus obtains normal centre frequency, ensure that the accuracy of follow-up extra large state parametric inversion.By the method for doppler spectral centering frequency as shown in formula (2), wherein f is Doppler frequency, and P is doppler spectral amplitude.

$f_d=\frac{\∫f\·P\left(f\right)df}{\∫P\left(f\right)df}---\left(2\right)$

The position centre frequency originally that Wave Breaking occurs in Fig. 5 is very large, destroys the Changing Pattern of centre frequency sequence, after the data of process breaker interference, obtains centre frequency more accurately.In Fig. 6, bold portion is all that data all recover normal after treatment, as is shown in phantom lines, eliminate the interference of breaker because breaker interference causes centre frequency deviation.

FT1 data in described step 1 are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

The process that bandwidth threshold scope in described step 2 is step 7 provides foundation, makes the doppler bandwidth after process in normal range.

Bandwidth left end point is made to be positioned at zero-frequency doppler spectral translation in described step 4, doppler spectral entirety is made to be positioned at the positive axis of x-axis, because breaker is all towards seashore along with wave, cause doppler spectral bandwidth to be widened to x-axis positive axis direction, translation doppler spectral can ensure that EMD decomposes and breaker can be decomposed as high fdrequency component and do not affect useful signal.

In described step 6, FT1 data are carried out in the intrinsic mode function that empirical mode decomposition EMD obtains, and breaker component may be present in first intrinsic mode function and IMF1 as high fdrequency component or be present in the first two intrinsic mode function IMF1 and IMF2;

According to doppler spectral bandwidth, described step 7 judges that remove IMF1 still rejects IMF1 and IMF2, ensure that namely the FT1 data doppler spectral bandwidth after process normally eliminates breaker interference and do not affect useful signal.

Embodiment 2:

Device embodiment 2 of the present invention belongs to same technical conceive with embodiment of the method 1, and the content of not detailed description in device embodiment 2, refers to embodiment of the method 1.

As shown in Figure 7, the device of a kind of S-band radar Doppler breaker AF panel of the present invention, comprising:

Breaker distance element position acquisition unit, for obtaining one group of radar return FT1 data, carry out pre-service, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the position of the distance element of each frame data breaker according to energy and centre frequency;

Bandwidth threshold scope acquiring unit, for getting the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, described bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

First judging unit, for getting the data of first distance element in this frame FT1 data, the result according to breaker distance position acquisition unit determines whether breaker interfering data; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward the 3rd judging unit to;

Doppler spectral processing unit, for by doppler spectral translation, makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data to the doppler spectral after translation;

EMD processing unit, carries out empirical mode decomposition EMD for the FT1 data new to this distance element, obtains a two or more intrinsic mode function IMF and trend function r _n(t);

High fdrequency component removal unit, for removing the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Second judging unit, for judging described bandwidth whether within the scope of bandwidth threshold, if so, then these data are the data after breaker process; If described band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to removing the data of IMF1, the data of reconstructed residual are the data after breaker process;

3rd judging unit, whether the data for judging when pre-treatment are the data of last distance element, if not, then get the data of next distance element, whether forward the first judging unit to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

Wherein, the FT1 data in described breaker distance element position acquisition unit are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

Wherein, in described EMD processing unit, the step of empirical mode decomposition EMD is as follows,

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero; So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 3., 4. () repeat step, calculate the 3rd mode C ₃(t);

7. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural intrinsic mode function IMF and trend function r _n(t).

Present invention, avoiding existing breaker disposal route to the adverse effect of radar inversion accuracy, the present invention is complete reservation useful signal while the interference of reduction breaker, for existing microwave Doppler radar system provides a kind of effective suppression breaker interference method, thus radar detection precision can be improved.

The above embodiment and application scenarios are only preferred embodiment of the present invention and application scenarios; not in order to limit the present invention; all any amendments done within the spirit and principles in the present invention, equivalent replace and improve and in the application of other field and scene, all should be included within protection scope of the present invention.

Claims (6)

1. a method for S-band radar Doppler breaker AF panel, is characterized in that: comprise the following steps:

Step 1, obtains one group of radar return FT1 data, carries out pre-service, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the position of the distance element of each frame data breaker according to energy and centre frequency;

Step 2, gets the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, described bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

Step 3, gets the data of first distance element in this frame FT1 data, determines whether breaker interfering data according to the result of step 1; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward step 8 to;

Step 4, by doppler spectral translation, makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data to the doppler spectral after translation;

Step 5, the FT1 data new to this distance element carry out empirical mode decomposition EMD, obtain a two or more intrinsic mode function IMF and trend function r _n(t);

Step 6, removes the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Step 7, judge described bandwidth whether within the scope of bandwidth threshold, if so, then these data are the data after breaker process; If described band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to removing the data of IMF1, the data of reconstructed residual are the data after breaker process;

Step 8, whether the data judging when pre-treatment are the data of last distance element, if not, then whether get the data of next distance element, forward step 3 to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

2. the method for a kind of S-band radar Doppler breaker AF panel as claimed in claim 1, it is characterized in that: the FT1 data in described step 1 are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

3. the method for a kind of S-band radar Doppler breaker AF panel as claimed in claim 1, is characterized in that: in described step 5, the step of empirical mode decomposition EMD is as follows,

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero; So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 3., 4. () repeat step, calculate the 3rd mode C ₃(t);

7. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural intrinsic mode function IMF and trend function r _n(t).

4. a device for S-band radar Doppler breaker AF panel, is characterized in that: comprising:

Breaker distance element position acquisition unit, for obtaining one group of radar return FT1 data, carry out pre-service, obtain the bandwidth of all distance element doppler spectrals, centre frequency and energy, obtain the position of the distance element of each frame data breaker according to energy and centre frequency;

Bandwidth threshold scope acquiring unit, for getting the data of all distance elements in these group data, obtains a bandwidth threshold scope, and wherein, described bandwidth threshold scope is that the minimum value of other distance element bandwidth except breaker distance element is to maximal value;

First judging unit, for getting the data of first distance element in this frame FT1 data, the result according to breaker distance position acquisition unit determines whether breaker interfering data; If breaker interfering data, ask doppler spectral, calculate doppler spectral centre frequency, bandwidth left and right endpoint location; If not breaker interfering data, then forward the 3rd judging unit to;

Doppler spectral processing unit, for by doppler spectral translation, makes bandwidth left end point move to zero-frequency place, does inversefouriertransform obtain new FT1 data to the doppler spectral after translation;

EMD processing unit, carries out empirical mode decomposition EMD for the FT1 data new to this distance element, obtains a two or more intrinsic mode function IMF and trend function r _n(t);

High fdrequency component removal unit, for removing the high fdrequency component IMF1 at breaker interference place, reconstructs all the other IMF and trend function r _nt () obtains new FT1 data, ask the bandwidth of doppler spectral and doppler spectral;

Second judging unit, for judging described bandwidth whether within the scope of bandwidth threshold, if so, then these data are the data after breaker process; If described band is wider than the maximal value of bandwidth threshold scope, then reject time high fdrequency component IMF2 again to removing the data of IMF1, the data of reconstructed residual are the data after breaker process;

3rd judging unit, whether the data for judging when pre-treatment are the data of last distance element, if not, then get the data of next distance element, whether forward the first judging unit to, be that breaker interfering data judges to the data of next distance element; If so, represent all data of this frame are all disposed.

5. the device of a kind of S-band radar Doppler breaker AF panel as claimed in claim 4, it is characterized in that: the FT1 data in described breaker distance element position acquisition unit are that the original signal that radar receives does the data after Fourier transform, and judge according to the energy of doppler spectral and centre frequency feature the distance element that breaker occurs.

6. the device of a kind of S-band radar Doppler breaker AF panel as claimed in claim 4, is characterized in that: in described EMD processing unit, the step of empirical mode decomposition EMD is as follows,

1. the maximum value of FT1 data original time series x (t) received and minimal value are done cubic spline difference respectively, obtain lower enveloping curve;

2. the mean value getting lower enveloping curve forms average m ₁t (), then deducts m by x (t) ₁t () forms another curve h ₁(t), that is:

x(t)-m ₁(t)＝h ₁(t)

3. to h ₁t 1. () repeat, 2. obtain h ₂(t), that is:

h ₁(t)-m ₂(t)＝h ₂(t)

Wherein, m ₂t () is h ₁the Mean curve of the mean value formation of the upper lower enveloping curve of (t);

4. 1., 2., 3. above-mentioned steps is repeated down, until the h obtained _kt () is an IMF, that is:

h _k(t)＝h _k-1(t)-m _k(t)

IMF need meet following 2 conditions: 1) in whole data field, extreme point number differs 1 at the most with zero crossing number; 2) in arbitrfary point, the coenvelope of signal and the mean value of lower envelope are zero; So just from x (t), decomposite first mode h _kt () is also designated as C ₁(t), i.e. IMF1, such processing procedure is called screening process;

5. x (t) is deducted first mode C ₁t (), forms new signal r ₁(t), that is:

x(t)-C ₁(t)＝r ₁(t)

Again to r ₁t 1., 2., 3., 4. () repeat step, calculate second mode C ₂(t);

6. by r ₁t () deducts C ₂t () forms again new signal r ₂(t), that is:

r ₁(t)-C ₂(t)＝r ₂(t)

Again to r ₂t 1., 2., 3., 4. () repeat step, calculate the 3rd mode C ₃(t);

7. so step is repeated 1., 2., 3., 4., r to the last _nt () is a monotonic quantity, so just x (t) has been decomposited a plural intrinsic mode function IMF and trend function r _n(t).