CN104267389A - Signal processing method for MIMO (Multiple-Input Multiple-Output) sky-wave OTHR (Over-the-horizon Radar) - Google Patents

Abstract

The invention provides a signal processing method for an MIMO (Multiple-Input Multiple-Output) sky-wave OTHR (Over-the-horizon Radar). By utilizing the advantages that an MIMO-OTHR distinguishes multi-path echoes of a target, the multi-path echoes of a target are separated at the signal processing end of the MIMO-OTHR, so that an association relationship between the multi-path measurement of the target and propagation paths is obtained, and the processing complexity of OTHR data is greatly reduced by virtue of the multi-path measurement and the propagation paths. Compared with a conventional OTHR data processing mode, a data processing mode of the separated multi-path echoes through the MIMO-OTHR has the advantages that the calculated amount is greatly decreased, and the two modes are not obviously different in accuracy.

Description

A kind of MIMO sky-wave OTH radar signal processing method

[technical field]

The present invention relates to a kind of signal processing method for sky-wave OTH radar, the signal processing method of the sky-wave OTH radar under especially a kind of multiple-input and multiple-output system.

[background technology]

Over-the-horizon radar (Over-the-horizon radar:OTHR), is a kind of detection range restriction that can overcome sighting distance and bring, can detects the radar of the following overlength distance target of sighting distance.By the difference of signal propagation path, OTHR can be divided into sky wave OTHR and earthwave OTHR.Wherein the signal of sky wave OTHR is by ionospheric reflected illumination to the following target of sighting distance, and returns the receiving end of sky wave OTHR by ionospheric secondary reflection thus detection sighting distance following target.Because over-the-horizon radar can detect the following target of sighting distance, therefore its operating distance is long, and area coverage is large, militarily has important early warning effect, is recently subject to the most attention of various countries military scientist.

Sky wave OTHR utilizes the distant object in below ionospheric probing local horizon, but ionospheric complex characteristics and the special working method of sky wave OTHR make the signal transacting of sky wave OTHR and data processing face many problem demanding prompt solutions.The multipath that ionosphere causes, multimode effect seriously reduce the serviceability of sky wave OTHR.Therefore in order to improve and improve the serviceability of sky wave OTHR further, multipath, multimode effect how to remove ionosphere and cause must be studied.Simultaneously due to the complicacy of multipath, multimode echo, make deionization layer multipath, difficult point and emphasis that multimode effect becomes the engineering research of sky wave OTHR radar system.

[summary of the invention]

Based on above problem, the present invention proposes:

A kind of MIMO sky-wave OTH radar signal processing method, is characterized in that comprising step:

It is two-dimensional array that A arranges radar array, and adopts the mode of structuring the formation of minimum-redundancy linear arrays in the pitch direction;

B arranges its transmitted waveform and integrates as time domain dislocation linear frequency modulation continuous wave, or is frequency domain dislocation linear frequency modulation continuous wave;

C carries out multi-path separation to launch and accept united beam according to communication mode;

D carries out range Doppler process to the signal of often kind of communication mode;

E carries out measuring signal process to the signal of often kind of communication mode;

F, according to the corresponding relation of often kind of communication mode and measuring signal, adopts PDA algorithm to carry out in data place;

G obtains targetpath;

Wherein said measuring signal process comprises:

E1 leaves angle to wave beam and estimates;

E2 carries out Wave beam forming process to received signal, obtains the pointing direction of received beam;

E3 carries out each waveform that matched filtering is concentrated to be separated transmitted waveform to transmitting;

E4 estimates the wave beam angle of arrival;

E5 carries out Wave beam forming process to transmitting, and obtains the pointing direction of launching beam;

E6 extracts the range information of target;

E7, to multiple echo cycle, after above-mentioned matched filtering and Wave beam forming process, carries out the doppler processing of slow time, obtains Doppler shift and the movement velocity of target.

Method as above, wherein the dislocation mode of time domain dislocation linear frequency modulation continuous wave is that the initial time of linear frequency modulation continuous wave is uniformly distributed in a waveform recurrence interval.

Method as above, the dislocation mode of its frequency domain dislocation line Continuous Wave with frequency modulation is that the initial Doppler frequency of each waveform of linear frequency modulation continuous wave is uniformly distributed in waveform repetition frequency.

Method as above, wherein transmitted waveform collection switches according to the target speed recorded before this, in speed lower than selecting time domain dislocation linear frequency modulation continuous wave during predetermined threshold, in speed higher than selecting frequency domain dislocation linear frequency modulation continuous wave during predetermined threshold.

Method as above, wherein communication mode comprises: EE pattern, EF pattern, FE pattern and FF pattern.

[accompanying drawing explanation]

Fig. 1 is the schematic diagram of the signal processing method that the present invention proposes

[embodiment]

Due to ionospheric hierarchical nature, OTHR transmits and may reflect in ionospheric different layering, form the travel path of many radars to target, cause radar receiving end to receive and multiplely correspond to the echo of same target, Here it is so-called multipath effect.Multipath effect causes producing false target in OTHR signal processing, has a strong impact on its performance.Consider that multipath echo has different DoD (wave beam leaves angle) or DoA (the wave beam angle of arrival) in the pitch direction, the general Adaptive beamformer that adopts carrys out filtering multipath echo.OTHR is due to its phased array system characteristic for tradition, can not form effective launching beam, is therefore difficult to the impact that elimination multipath echo brings.Such as suppose that OTHR transmits and may reflect at E-LAYER and F layer, and only there is the situation of single-hop, then same target may produce 4 echoes at receiving end.These 4 echoes are referred to as EE pattern, EF pattern, (EF pattern represents to transmit and arrives target in the reflection of E layer for FE pattern and FF pattern, backscattering echo arrives radar receiving end in the reflection of F layer, all the other are similar), suppose that removing multipath effect target is retain EE pattern, all the other 3 patterns of filtering.Tradition OTHR can only form adaptive beam at receiving end, thus EF and the FF pattern that filtering is different from EE pattern DoA.Launching beam is formed, because OTHR receiving end and transmitting terminal split, training data is sent to transmitting terminal from receiving end there is certain delay, and ionosphere has time-varying characteristics, therefore effectively can not form launching beam, is difficult to filtering FE pattern.And MIMO radar has Wave beam forming ability flexibly, can received beam be formed at receiving end, can also launching beam be formed.Form launching beam at radar receiving end and be called as the formation of " non-causal " (non-causal) launching beam, because its launching beam is launched at signal, arrived target and carry out after turning back to receiving end.Due to " non-causal " launching beam Formation and characteristics of MIMO radar, apply it in OTHR the impact well can eliminated multipath effect and bring, the OTHR therefore based on MIMO system has better multipath effect rejection ability relative to traditional OTHR.

Except multipath effect, the another kind of interference having a strong impact on traditional OTHR performance is spread clutter.Already described above, OTHR due to its distinctive under make in its echo containing powerful Haiti clutter depending on working method.In OTHR running environment, when clutter arrives receiving end in ionospheric layer (the such as F layer) reflection of instability, this clutter, owing to polluting through unstable ionospheric phase place, is just formed and carrys out spread clutter.When the distance by radar (group delay) of this clutter drops on same range unit with the distance by radar of target echo (target echo reflects through more stable ionospheric layer, such as E layer), target echo may be expanded clutter and cover.Echo through the reflection of F layer is subject to serious ionosphere phase place pollution, and reacting on Doppler frequency territory is then video stretching, and the clutter therefore through this layer of reflection is called " spread clutter ".This means any distance unit, all may observe stable target EE pattern and unstable spread clutter EF pattern, FE pattern and FF pattern, be referred to as " multimode effect ".Under normal circumstances, multimode effect produce various modes be produced by the ground scatter of diverse geographic location, this and multipath effect be by the ground of same position (i.e. same target) scattering produce different.Therefore the multimode in multimode effect also has different DoD or DoA in the pitch direction, and this is owing to having enough large difference in height between ionospheric layer apart from (the about 220km of E layer height about 100km, F layer).But EE pattern and EF pattern are at the DoD of pitch orientation, or EF pattern and FF pattern are at the DoA of pitch orientation, owing to there being similar Geometrical propagation path, almost do not have difference.Depend merely on launching beam or received beam cannot differentiate these multimode propagation patterns completely, only have and MIMO radar technology is applied in OTHR, OTHR just can be made to have effective launching beam formed and received beam formation, the impact of the spread clutter that effective filtering brings due to multimode effect and ionosphere contamination simultaneously.

The difficult problem that another traditional OTHR cannot avoid is that the angle of pitch of echo and the distance by radar residing for it have dependence (range-dependent).This is because ionosphere has hierarchical nature, and the echo in same pitch orientation may from different distance by radars, and this just requires that radar can do different Adaptive beamformer to distinguish these echoes at different distance by radar unit.And the launching beam of traditional OTHR may accomplish this point hardly, MIMO radar effectively can be done different launching beams at different distance unit because distinctive " non-causal " launching beam is formed and be formed, and therefore this is also by one of MIMO radar technology motivation being applied to OTHR.

Although relative to traditional OTHR, OTHR based on MIMO system has the ability better eliminating multipath effect, multimode effect and spread clutter, but its realization also exists many problems, one of them primary problem is mode of the structuring the formation problem of transmitting antenna array and receiving antenna array.Because OTHR is operated in high band, corresponding transmit receive antenna can reach rice up to a hundred, and antenna cost is more expensive, and therefore the emission array of traditional OTHR and receiving array generally adopt uniform linear array, only to different azimuth to region scan.And element number of array is less, general emission array element number of array is at about ten.Therefore, the uniform linear array that traditional OTHR adopts due to only in orientation to having aperture, can not be applied directly in the aerial array based on the OTHR of MIMO system.

In order to ensure from different pitch orientation multimode multi-path jamming with from different azimuth to interference can be eliminated simultaneously, array based on the OTHR of MIMO system upwards all must have array aperture in pitching and orientation, for this reason, its array must adopt two-dimensional array.

Another MIMO-OTHR problem that must consider of structuring the formation is that array must have larger aperture in pitch orientation.This is because the target of OTHR detection is all in beyond thousands of kilometer usually, much larger than layer height, target echo is by all having the very large angle of depression after ionospheric reflection, and the angle of depression between multipath echo relatively, need array beams figure to have very narrow main lobe width in the situation of the large angle of depression, just can tell these multipath echos.Consider general situation, hypothetical target and OTHR at a distance of 1000km, E-LAYER height 100km, F layer height 200km, are then respectively from the reflection of E layer with from its angle of depression of echo of F layer reflection

Wherein R is ground distance, h _e, h _fbe respectively the height of E layer and F layer.Namely be no more than 4 ° at its main lobe width of status requirement of array beams Figure 86 °, therefore require that MIMO-OTHR array has very large aperture in pitch orientation.Increasing a way of array aperture is the number increasing array element in array, but must increase element number of array at double when MIMO-OTHR adopts two dimension to structure the formation, and this is unpractical to the OTHR having huge bay.Another effective way is exactly the mode that array elements adopts Thinned arrays, and the half-wavelength array element distance that the even linear array broken traditions adopts makes array element sparse distribution, reaches the object increasing array aperture.

Theoretical analysis shows, when array element number is certain, minimum-redundancy linear arrays has maximum array aperture in linear array.Therefore, when OTHR array element number increases limited, we propose MIMO-OTHR two-dimensional array and adopt minimum-redundancy linear arrays to structure the formation mode in the pitch direction, can differentiate multipath, the multimode echo with the large angle of depression in the pitch direction.

Tradition OTHR is when scanning water area, and the characteristic slow relative to its speed of aircraft due to surface vessel, Doppler frequency is low, OTHR is generally operational in high-doppler resolution model, and namely transmitted waveform adopts low f _wRFthe LFMCW (linear frequency modulation continuous wave) of (waveform repetition frequency).Now WRI (waveform recurrence interval) is longer, and OTHR maximum detectable range is subject to the restriction of ionospheric transmission, but not the restriction of WRI.Therefore LFMCW can be misplaced in time domain, produce the orthogonal waveforms collection that MIMO-OTHR needs, and do not affect the maximum detectable range of OTHR.A kind of desirable dislocation mode is that the initial time of orthogonal LFMCW is uniformly distributed in a WRI.This waveform is claimed to integrate as time domain dislocation LFMCW (Time-Staggered LFMCW).Strictly speaking, also not exclusively orthogonal between the waveform of this waveform collection, but at radar receiving end by after matched filtering, easily they can be separated time domain, reach object orthogonal between waveform.Time-Staggered LFMCW remains the advantage that LFMCW easily produces, emissive power is high simultaneously, is the more satisfactory waveform collection of MIMO-OTHR.Such as, the T of this waveform collection is supposed _wRI=0.25s (f _wRF=1/T _wRI=4Hz), altogether containing K waveform.Because the initial time of K waveform is uniformly distributed in a WRI, the therefore equivalent T of waveform collection _wRIk will be reduced doubly, i.e. maximum unam

$R_{\mathrm{unambiguous}}=\frac{{\mathrm{cT}}_{\mathrm{WRI}}}{2K}\≈6000\mathrm{km}---(1-2)$

Still the ultimate range that OTHR reality can detect is not affected.Time-Staggered LFMCW is relative to LFMCW, and its maximum unam (time delay) reduces K doubly, and the most very much not ambiguous Doppler frequency is constant, meets the conclusion that above-mentioned analysis obtains.The shortcoming of Time-Staggered LFMCW is due to its f _wRFlow, the detection of the target at a slow speed such as marine vessel can only be used for, for aircraft uniform velocity target faster, easily cause velocity ambiguity.

Another kind of similar waveform collection is frequency dislocation LFMCW (Frequency-Staggered LFMCW), and the initial Doppler frequency of each waveform is at f _wRFinside be uniformly distributed, through the slow time doppler processing of OTHR, Doppler frequency territory complete the separation to each orthogonal waveforms.Now, Frequency-Staggered LFMCW relative to LFMCW, its most very much not ambiguous Doppler frequency reduce K doubly, and maximum unam (time delay) remains unchanged, and meets the conclusion that above-mentioned analysis obtains equally.Frequency-Staggered LFMCW is commonly used in the fast targets such as OTHR hunter needs high f _wRFtime, reasonably select waveform number K to ensure that target does not occur velocity ambiguity.

Suppose that MIMO-OTHR two dimension emission array is made up of K emitting antenna, two-dimentional receiving array is made up of L receiving antenna.Orthogonal injection waveform collection

u(t)＝[u ₁(t),...,u _k(t),...,u _K(t)] ^T (1-3)

Containing the individual different waveform of K, and each periodic signal waves energy is equal.Therefore, each transmission antennas transmit orthogonal waveforms (when number of transmit antennas is greater than quadrature wave figurate number, launching orthogonal waveforms by dividing submatrix, not repeating them here).Suppose that the far-field region of MIMO-OTHR array exists a point target, then the echoed signal of this target that l receiving antenna receives can be expressed as

Wherein η ₀for random complex scattering coefficients, and suppose that all waveforms all have identical η ₀.τ ₀, ν ₀be respectively round trip time delay and the Doppler shift of target.And

Represent emission array steering vector and receiving array steering vector respectively, θ _d, θ _abe respectively target DoD and DoA in the horizontal direction, be respectively target DoD and DoA in the pitch direction.Then to whole receiving array, its Received signal strength can be written as vector form

When being below then MIMO-OTHR employing two dimension transmitting and receiving array, the signal model of single target echo.Note, only there is single communication mode in this model hypothesis target echo, but for when there is multipath transmisstion pattern, can release the signal model multipath transmisstion from this formula easily

Wherein p is multipath transmisstion MODE NUMBER.To the signal transacting basic skills of MIMO-OTHR be provided below, above formula will be processed, to obtain the information such as range-to-go, orientation, speed.

Theoretical according to MIMO Wave beam forming, when MIMO array is made up of K transmitting array element and L reception array element, and each transmitting array element launches different waveforms, then the launch and accept associating steering vector of its equivalence is made up of KL variable.Therefore the optimal beam forming of MIMO radar needs a calculating K L weight vector, and its calculated amount is very huge.But theoretical analysis shows, for this associating steering vector of formula (3-9), there is the MIMO signal model that Kronecker amasss form, the launch and accept associating steering vector of its equivalence can be reduced to and be made up of K+L variable, namely launching beam formation and received beam are formed and can separately carry out, and processing sequence can exchange.Therefore for the signal transacting of MIMO-OTHR, we propose first to carry out Wave beam forming process to received signal, then carry out follow-up distance to process, launching beam process etc.

Specifically, if represent the space DoD comprising level and pitch orientation, represent the space DoA comprising level and pitch orientation.Then signal model can be expressed as again

$Z\left(t\right)={\mathrm{\η}}_0{a}_L\left(\mathrm{\Θ}\right)a_K^T\left(\mathrm{\Φ}\right)u(t-{\mathrm{\τ}}_0)e^{j2\mathrm{\π}{v}_{0}t}---(1-8)$

If received beam weight vector

ω _r(Θ)＝a _L(Θ) (1-9)

First DoD is estimated, order

y(t,Θ)＝ω _r(Θ) ^HZ(t) (1-10)

Two-dimensional directional Θ searches for y (t, Θ), the estimated value of target DoD can be obtained

${\widehat{\mathrm{\Θ}}}_0=\max {\arg }_{\mathrm{\Θ}}\left|y(t,\mathrm{\Θ})\right|---(1-11)$

Obtain the estimated value of DoD, just can carry out received beam formation.Its received beam weight vector both can adopt

${\mathrm{\ω}}_r\left({\widehat{\mathrm{\Θ}}}_0\right)=a_L\left({\widehat{\mathrm{\Θ}}}_0\right)---(1-12)$

Also some self-adaptations can be adopted to weigh, such as famous MVDR weight vector

${\mathrm{\ω}}_r\left({\widehat{\mathrm{\Θ}}}_0\right)=\frac{R^{-1}{a}_L\left({\widehat{\mathrm{\Θ}}}_0\right)}{{a_L}^H\left({\widehat{\mathrm{\Θ}}}_0\right)R^{-1}{a}_L\left({\widehat{\mathrm{\Θ}}}_0\right)}---(1-13)$

After received beam process, signal becomes

$\begin{array}{c}y(t,{\widehat{\mathrm{\Θ}}}_0)={\mathrm{\ω}}_r{\left({\widehat{\mathrm{\Θ}}}_0\right)}^{H}Z\left(t\right)={\mathrm{\η}}_0{\mathrm{\ω}}_r{\left({\widehat{\mathrm{\Θ}}}_0\right)}^H{a}_L\left(\mathrm{\Θ}\right)a_K^T\left(\mathrm{\Φ}\right)u(t-{\mathrm{\τ}}_0)e^{j2\mathrm{\π}{v}_{0}t}\\ ={\mathrm{\η}}_0{F}_r\left({\widehat{\mathrm{\Θ}}}_0\right)a_K^T\left(\mathrm{\Φ}\right)u(t-{\mathrm{\τ}}_0)e^{j2\mathrm{\π}{v}_{0}t}\end{array}---(1-14)$

Wherein for pointing to the received beam in direction.

Next be that launching beam formation is carried out to signal.Form launching beam, each transmitted waveform in transmitted waveform collection u (t) must be separated.Suppose that in orthogonal waveforms collection u (t), any two waveforms have desirable orthogonality in time domain, then meet

$\underset{-T/2}{\overset{T/2}{\∫}}{u}_i\left(t\right)u_j^{*}(t-\mathrm{\τ})\mathrm{dt}=\left\{\begin{array}{cc}{E}_0\mathrm{\δ}\left(\mathrm{\τ}\right),& i=j\\ 0,& i\≠j\end{array}\right.---(1-15)$

Wherein E ₀for the energy of each waveform in one-period, T is the cycle of each transmitted waveform.Because what OTHR launched is all periodic signal, only require that waveform is orthogonal in one-period, so the limit of integration only gets one-period.

Have with after co-relation, matched filtering just can be utilized to be separated by orthogonal waveforms.Will respectively with K waveform u _it () carries out matched filtering, obtain the vector that transmits of equivalence

$Y(t,{\widehat{\mathrm{\Θ}}}_0)={\mathrm{\η}}_0{E}_0{F}_r\left({\widehat{\mathrm{\Θ}}}_0\right)\mathrm{\δ}\left({\mathrm{\τ}}_0\right)e^{j2\mathrm{\π}{v}_{0}t}{a}_K^T\left(\mathrm{\Φ}\right)---(1-16)$

Now, just can at OTHR receiving end, the launching beam doing equivalence is formed.Its flow process and received beam are formed the same, first the DoA of estimated signal.If launching beam weight vector is ω _t(Φ)=a _k(Φ), with season

$x(t,{\widehat{\mathrm{\Θ}}}_0,\mathrm{\Φ})={{\mathrm{\ω}}_t}^H\left(\mathrm{\Φ}\right)Y(t,{\widehat{\mathrm{\Θ}}}_0)---(1-17)$

Equally, at the enterprising line search of two-dimensional directional Φ, the estimated value of target DoA can be obtained

${\widehat{\mathrm{\Φ}}}_0=\max {\arg }_{\mathrm{\Φ}}\left|x(t,{\widehat{\mathrm{\Θ}}}_0,\mathrm{\Φ})\right|---(1-18)$

Obtain the estimated value of DoA, just can carry out launching beam formation.If launching beam weight vector is then after launching beam process, signal becomes

$\begin{array}{c}x(t,{\widehat{\mathrm{\Θ}}}_0,{\widehat{\mathrm{\Φ}}}_0)={{\mathrm{\ω}}_t}^H\left({\widehat{\mathrm{\Φ}}}_0\right)Y(t,{\widehat{\mathrm{\Θ}}}_0)={\mathrm{\η}}_0{E}_0{F}_r\left({\widehat{\mathrm{\Θ}}}_0\right)\mathrm{\δ}\left({\mathrm{\τ}}_0\right)e^{j2\mathrm{\π}{v}_{0}t}{{\mathrm{\ω}}_t}^H\left({\widehat{\mathrm{\Φ}}}_0\right)a_K\left(\mathrm{\Φ}\right)\\ ={\mathrm{\η}}_0{E}_0{F}_r\left({\widehat{\mathrm{\Θ}}}_0\right)F_t\left({\widehat{\mathrm{\Φ}}}_0\right)\mathrm{\δ}\left({\mathrm{\τ}}_0\right)e^{j2\mathrm{\π}{v}_{0}t}\end{array}---(1-19)$

Wherein for pointing to the launching beam in direction, the launch and accept united beam of MIMO-OTHR can be regarded as.So far, obtained the azimuth information that target is all, and the range information of target can at δ (τ ₀) middle extraction, velocity information is then to multiple echo cycle, after above-mentioned matched filtering and wave beam process, carries out the doppler processing of slow time, obtains Doppler shift and the movement velocity of target.

The signal processing method more than discussed for be the situation that target only exists a communication mode, for the situation that there is multipath target echo and multimode spread clutter, its disposal route is still similar.Because when targeted propagation pattern required for the bearing sense in weight vector, other multipaths from different azimuth, multimode clutter all will by filterings.In addition, no matter launching beam and received beam, at the different beam weight vector of different distance unit application, can realize the Wave beam forming of different distance unit, this be eliminate from the multipath of different distance unit, multimode clutter necessary.But traditional OTHR is due to the reason of phased array system, receive data and must be sent to transmitting terminal kilometer up to a hundred to control launching beam from receiving end, and ionosphere becomes when being, through one section time, delay the Launch Right vector calculated do not met current ionosphere environment.Therefore traditional OTHR may form effective launching beam hardly, and " non-causal " launching beam Formation and characteristics that MIMO-OTHR has can accomplish this point well.Consider and must utilize launching beam filtering multipath echo (such as target exists EE pattern and FE pattern) in some cases to only have MIMO technology to be applied in OTHR and could realize eliminating multipath, multimode impact to greatest extent.

OTHR based on MIMO system has the advantage of " non-causal " due to its launching beam, if emission array and receiving array all adopt two-dimentional battle array, can differentiate the multipath echo under any travel path in theory, therefore have " model selection " characteristic.In order to utilize this advantage of MIMO-OTHR to improve the data-handling efficiency of OTHR, we propose by all targeted propagation patterns difference " selection " out, namely the multipath echo of same target is separated, carry out range Doppler process, then respectively signal transacting is carried out to the echo under often kind of communication mode, obtain the measurement under this communication mode, finally carry out data processing again.Can be found by such processing mode, measure the travel path associated with it just to determine before data processing, and had the incidence relation of measurement and travel path, greatly can simplify the complexity of OTHR data processing, measure accurately simultaneously and can improve target tracking accuracy further with the incidence relation in path.Especially, above processing mode is applied in MPDA (multipath probality data association multipath probabilistic data association) algorithm, can find that MPDA algorithm will to deteriorate to more and relatively simple PDA (probablity data association probabilistic data association) algorithm, signal and the data aggregate treatment scheme of MIMO-OTHR can represent as Fig. 1.

The foregoing is only the example of the present invention's preferably embodiment, and be not used to limit interest field of the present invention; Simultaneously above description, for correlative technology field, special personage should understand and implement, and therefore other equivalences completed under not departing from disclosed spirit change or modify, and all should comprise in the claims.

Claims (5)

1. a MIMO sky-wave OTH radar signal processing method, is characterized in that comprising step:

It is two-dimensional array that A arranges radar array, and adopts the mode of structuring the formation of minimum-redundancy linear arrays in the pitch direction;

B arranges its transmitted waveform and integrates as time domain dislocation linear frequency modulation continuous wave, or is frequency domain dislocation linear frequency modulation continuous wave;

C carries out multi-path separation to launch and accept united beam according to communication mode;

D carries out range Doppler process to the signal of often kind of communication mode;

E carries out measuring signal process to the signal of often kind of communication mode;

F, according to the corresponding relation of often kind of communication mode and measuring signal, adopts PDA algorithm to carry out in data place;

G obtains targetpath;

Wherein said measuring signal process comprises:

E1 leaves angle to wave beam and estimates;

E2 carries out Wave beam forming process to received signal, obtains the pointing direction of received beam;

E3 carries out each waveform that matched filtering is concentrated to be separated transmitted waveform to transmitting;

E4 estimates the wave beam angle of arrival;

E5 carries out Wave beam forming process to transmitting, and obtains the pointing direction of launching beam;

E6 extracts the range information of target;

E7, to multiple echo cycle, after above-mentioned matched filtering and Wave beam forming process, carries out the doppler processing of slow time, obtains Doppler shift and the movement velocity of target.

2. the method for claim 1, wherein the dislocation mode of time domain dislocation linear frequency modulation continuous wave is that the initial time of linear frequency modulation continuous wave is uniformly distributed in a waveform recurrence interval.

3. the method for claim 1, the dislocation mode of its frequency domain dislocation line Continuous Wave with frequency modulation is that the initial Doppler frequency of each waveform of linear frequency modulation continuous wave is uniformly distributed in waveform repetition frequency.

4. the method for claim 1, wherein transmitted waveform collection switches according to the target speed recorded before this, in speed lower than selecting time domain dislocation linear frequency modulation continuous wave during predetermined threshold, in speed higher than selecting frequency domain dislocation linear frequency modulation continuous wave during predetermined threshold.

5. the method for claim 1, wherein communication mode comprises: EE pattern, EF pattern, FE pattern and FF pattern.