CN104569924B - Fuzzy-free region area expansion oriented incoherent MIMO radar waveform design method - Google Patents

Abstract

The invention discloses a fuzzy-free region area expansion oriented incoherent MIMO (Multi-Input Multi-output) radar waveform design method. The method comprises the following steps: creating a frequency orthogonal waveform model, comprising a plurality of waveforms, of incoherent MIMO radar, wherein any two waveforms in the waveform model can be kept orthogonal in the coherent processing time; adjusting frequency intervals between every two adjacent waveforms in the waveform group, so as to enable the incoherent MIMO radar fuzzy-free Doppler to be 1/T, meanwhile enabling the incoherent MIMO radar fuzzy-free time delay to be T which is a pulse repetition period. According to the fuzzy-free region area expansion oriented incoherent MIMO radar waveform design method disclosed by the invention, the frequency interval values of any two waveforms in the incoherent MIMO radar frequency orthogonal waveform group can be adjusted to fuzzy function section fuzzy-free Doppler of the incoherent MIMO radar to be 1/T, so that the incoherent MIMO radar fuzzy-free region area keeping orthogonal can be expanded.

Description

A kind of incoherent mimo radar waveform method for designing towards the extension of no confusion region area

Technical field

The present invention relates to field of radar, more particularly to a kind of incoherent mimo radar towards the extension of no confusion region area Waveform design method.

Background technology

At present both at home and abroad with regard to mimo technology of radar waveform design, mainly solve the orthogonality design problem of sets of waveforms, profit With the various design optimizing such as genetic algorithm, only the secondary lobe of correlation function between different wave is reduced it is impossible to effectively solving Incoherent mimo radar no confusion region area reduces problem.

Content of the invention

The technical problem to be solved in the present invention is to provide a kind of relevant mimo radar wave towards the extension of no confusion region area Shape method for designing, in order to solve to be unable to effectively solving incoherent mimo radar no confusion region face in prior art radar Waveform Design The long-pending problem reducing.

For solving above-mentioned technical problem, the present invention provides a kind of incoherent mimo radar towards the extension of no confusion region area Waveform design method, comprising: set up the model of the frequency orthogonal sets of waveforms of several waveforms of inclusion of incoherent mimo radar, ripple In shape group, any two waveform keeps orthogonal within the Coherent processing time；

In adjustment sets of waveforms between two adjacent waveforms frequency interval so that incoherent mimo radar no ambiguous Doppler is 1/ T, makes the no fuzzy time delay of incoherent mimo radar be t, wherein t is the pulse repetition period simultaneously.

The present invention has the beneficial effect that: the present invention passes through in the frequency orthogonal sets of waveforms adjust incoherent mimo radar arbitrarily The value of the frequency interval of two waveforms, so that incoherent mimo radar ambiguity function section no ambiguous Doppler is 1/t, extends Keep orthogonal incoherent mimo radar no confusion region area.

Brief description

Fig. 1 for the present invention implement one of towards clutter recognition incoherent mimo radar waveform method for designing flow process Figure；

Fig. 2 a is prior art incoherent mimo radar ambiguity function zero Doppler slice figure；

Fig. 2 b is prior art incoherent mimo radar ambiguity function top view；

Fig. 3 a is the incoherent mimo radar ambiguity function zero Doppler slice figure using the method in the embodiment of the present invention；

Fig. 3 b is the incoherent mimo radar ambiguity function top view using the method in the embodiment of the present invention.

Specific embodiment

In order to solve to be unable to effectively solving incoherent mimo radar no confusion region area in prior art radar Waveform Design The problem reducing, the invention provides a kind of incoherent mimo radar waveform method for designing towards the extension of no confusion region area, Below in conjunction with accompanying drawing and embodiment, the present invention will be described in further detail.It should be appreciated that concrete reality described herein Apply example only in order to explain the present invention, do not limit the present invention.

As shown in figure 1, a kind of incoherent mimo radar waveform method for designing towards the extension of no confusion region area, comprising:

S101, sets up the model of the frequency orthogonal sets of waveforms of several waveforms of inclusion of incoherent mimo radar, sets of waveforms Middle any two waveform keeps orthogonal within the Coherent processing time；

S102, in adjustment sets of waveforms between two adjacent waveforms frequency interval so that how general incoherent mimo radar is no fuzzy Strangle as 1/t, make the no fuzzy time delay of incoherent mimo radar be t, wherein t is the pulse repetition period simultaneously.

Wherein, specifically adopt in following formula adjustment sets of waveforms frequency interval between two adjacent waveforms so that in sets of waveforms arbitrarily Two waveforms keep orthogonal within the Coherent processing time:

δ f mt=a (4)

Wherein δ f is frequency interval between two adjacent waveforms in sets of waveforms, and m is the pulse number in pulse, and t is pulse weight In the multiple cycle, a is any positive integer.

Following formula is specifically adopted to continue in adjustment sets of waveforms frequency interval between two adjacent waveforms so that incoherent mimo radar Slice of ambiguity function no ambiguous Doppler is 1/t:

δ f=p/t (12)

Wherein, δ f is frequency interval between two adjacent waveforms in sets of waveforms, and t is the pulse repetition period, and p is positive integer.

The method of the embodiment of the present invention passes through any two ripple in the frequency orthogonal sets of waveforms adjust incoherent mimo radar So that incoherent mimo radar ambiguity function section no ambiguous Doppler is 1/t, extension just keeps the value of the frequency interval of shape The incoherent mimo radar no confusion region area handed over.

In order to be best understood from the method shown in Fig. 1 in the embodiment of the present invention, below adopt wide variety of incoherent pulses As a example string radar waveform, the method in the embodiment of the method shown in Fig. 1 is described in detail, certainly in specific implementation process, The incoherent radar signal model set up can also be using other the incoherent mimo radar signal models being originally practiced without description.

Step 1, sets up incoherent mimo radar signal model, wide variety of incoherent pulses string radar waveform is:

$x\left(t\right)=\underset{r=0}{\overset{m-1}{\mathrm{\σ}}}u(t-\mathrm{rt}),---\left(1\right)$

$u\left(t\right)=\frac{1}{\sqrt{w}},-w/2<t<w/2---\left(2\right)$

Wherein, x (t) is the baseband signal of train of pulse, and u (t) is rectangular pulse, and r is the numbering of certain pulse in train of pulse, M is the pulse number in pulse；T is the pulse repetition period；Mt is the Coherent processing time (cpi) of incoherent pulses string, and w is arteries and veins Rush width, t express time.

Step 2, chooses incoherent mimo radar and adopts the frequency orthogonal sets of waveforms including n waveform as detection waveform:

{s_n(t)=x (t) exp [j2 π (n δ f) t], n=1,2...n } (3)

Wherein, δ f is frequency interval between two adjacent waveforms in sets of waveforms.

Step 3, frequency interval between two adjacent waveforms in adjustment sets of waveforms, the value of this frequency interval makes in sets of waveforms Any two waveform keeps orthogonal within the Coherent processing time:

δ f mt=a (4)

Wherein, a is any positive integer.

Step 4, sets up incoherent mimo radar ambiguity function, is defined as:

${\left|a{f}_{\mathrm{mimo}}(\mathrm{\&tau;},f_d)\right|}^2=\frac{1}{n}\&centerdot;\underset{n=1}{\overset{n}{\mathrm{\&sigma;}}}\underset{n^{\&prime;}=1}{\overset{n}{\mathrm{\&sigma;}}}{\left|a{f}_{n{n}^{\&prime;}}(\mathrm{\&tau;},f_d)\right|}^2---\left(5\right)$

Wherein | afnn ' (τ, fd) | is the cross ambiguity function of two waveforms sn (t) and sn ' (t):

$a{f}_{n{n}^{\&prime;}}(\mathrm{\&tau;},f_d)=\underset{-\&infin;}{\overset{\&infin;}{\&integral;}}{s}_n\left(t\right)s_{n^{\&prime;}}*(t-\mathrm{\&tau;})\exp \left[j2\mathrm{\&pi;}{f}_{d}t\right]\mathrm{dt}---\left(6\right)$

In above formula, 1/n is normalization factor, n and n ' refers to the numbering in subpulse string, (τ, f_d) it is target echo signal Time delay and Doppler frequency shift move.

According to formula (5), relational expression (3) and (4) are substituted into (6)

Obtain:

${\left|a{f}_{\mathrm{mimo}}(\mathrm{\&tau;},f_d)\right|}^2=\underset{k=(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}(1-\frac{\left|k\right|}{n}){\left|a{f}_{\mathrm{simo}}\right[\mathrm{\&tau;},f_d+\mathrm{k\&delta;f}\left]\right|}^2---\left(7\right)$

Wherein af_simo(τ, fd) is the simo radar ambiguity function with single waveform x (t) as detectable signal:

$a{f}_{\mathrm{simo}}(\mathrm{\&tau;},f_d)=\underset{-\&infin;}{\overset{\&infin;}{\&integral;}}x\left(t\right)x*(t-\mathrm{\&tau;})\&centerdot;\exp \left[j2{\mathrm{\&pi;f}}_{d}t\right]\mathrm{dt}.---\left(8\right)$

Simo radar ambiguity function is:

$a{f}_{\mathrm{simo}}(\mathrm{\&tau;},f_d)=\exp \left\{j2\mathrm{\&pi;}{f}_d\right[\mathrm{\&tau;}+(m-1)t\left]\right\}\&centerdot;\underset{m=-(m-1)}{\overset{m-1}{\mathrm{\&sigma;}}}\frac{\sin \left[\mathrm{\&pi;}{f}_d(w-|\mathrm{\&tau;}-\mathrm{mt}\left|\right)\right]}{\mathrm{\&pi;}{f}_{d}w}\&centerdot;\frac{\sin \left[\mathrm{\&pi;}{f}_d(m-|m\left|\right)t\right]}{m\sin \left(\mathrm{\&pi;}{f}_{d}t\right)}---\left(9\right)$

Step 5, based on keeping orthogonal incoherent mimo radar and setting up incoherent mimo radar ambiguity function, in (7) In make τ=0 obtain:

${\left|a{f}_{\mathrm{mimo}}(0,f_d)\right|}^2={\left|a{f}_{\mathrm{simo}}\right[\mathrm{\&tau;},f_d+\mathrm{k\&delta;f}\left]\right|}^2+\underset{k\&notequal;0}{\underset{k=-(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}}(1-\frac{\left|k\right|}{n}){\left|a{f}_{\mathrm{simo}}\right[0,f_d+\mathrm{k\&delta;f}\left]\right|}^2---\left(10\right)$

(11) formula shows, function section af_mimo(0,f_d) by simo radar function section af_mimo(0,f_d) and a series of in Heart peak value moves to the slice of ambiguity function af of following position_simo(0,f_d+ k δ f) superposition composition:

f_d=-k δ f, k=± 1, ± 2... ± (n-1) (11)

According to (10), function section af_mimo(0,f_d) by simo radar function section af_mimo(0,f_d) and translation is fuzzy Function section af_simo(0,f_d+ k δ f) superposition composition, wherein af_mimo(0,f_d) and af_simo(0,f_d+ k δ f) Doppler's graing lobe Period distances (i.e. no ambiguous Doppler) are all 1/t.Therefore, if af_simo(0,f_d+ k δ f) cycle graing lobe and af_mimo(0, f_d) cycle graing lobe overlapping, then af after being superimposed_mimo(0,f_d) graing lobe period distances still be 1/t.

Step 6, based on this thought, continues in adjustment sets of waveforms frequency interval between two adjacent waveforms so that incoherent Mimo radar ambiguity function section no ambiguous Doppler is 1/t, makes δ f value:

δ f=_p/t (12)

P is positive integer.Then each translation item af in formula_simo(0,f_d+ k δ f) central peak move to af_simo(0,f_d) graing lobe At kp/t, make each translation item af_simo(0,f_d+ k δ f) graing lobe and af_simo(0,f_d) graing lobe overlap, therefore, incoherent mimo Radar ambiguity function section af_mimo(0,f_d) graing lobe interval holding be 1/t, that is, no ambiguous Doppler be 1/t.

Hereinafter verify that the waveform optimization designing technique determining using embodiment of the present invention Chinese style can make incoherent mimo thunder Reach no fuzzy time delay and remain t, so that incoherent mimo radar no confusion region area is equal with simo radar.

Nothing for analyzing incoherent mimo radar obscures time delay, makes f in (7) formula_d=0 can obtain:

${\left|{\mathrm{af}}_{\mathrm{mimo}}(\mathrm{\&tau;},0)\right|}^2=\underset{k=-(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}(1-\frac{\left|k\right|}{n}){\left|{\mathrm{af}}_{\mathrm{simo}}\right[\mathrm{\&tau;},\mathrm{k\&delta;f}\left]\right|}^2---\left(13\right)$

Make f in (9)_d=k δ f is simultaneously updated to above formula and can obtain:

${\left|{\mathrm{af}}_{\mathrm{mimo}}(\mathrm{\&tau;},0)\right|}^2=\underset{k=-(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}(1-\frac{\left|k\right|}{n})|\underset{m=-(m-1)}{\overset{m-1}{\mathrm{\&sigma;}}}\frac{\mathrm{sim}\left[\mathrm{\&pi;k\&delta;f}(w-|\mathrm{\&tau;}-\mathrm{mt}\left|\right)\right]}{\mathrm{\&tau;k\&delta;fw}}\&centerdot;\frac{\sin \left[\mathrm{\&pi;k\&delta;f}(m-|m\left|t\right)\right]}{m\sin \left(\mathrm{\&pi;k\&delta;ft}\right)}{|}^2---\left(14\right)$

Lower surface analysis is when δ f value meets (13) formula, non-at simo radar graing lobe τ mt in delay-Doppler plane Relevant mimo radar whether there is graing lobe.(13) formula and τ=mt are substituted into (14) can obtain:

${\left|{\mathrm{af}}_{\mathrm{mimo}}(\mathrm{\&tau;},0)\right|}^2=\underset{k=-(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}(1-\frac{\left|k\right|}{n}){|\underset{m=-(m-1)}{\overset{m-1}{\mathrm{\&sigma;}}}\frac{\sin (\mathrm{\&pi;kpw}/t)}{\mathrm{\&pi;kpw}/t}\&centerdot;\frac{m-\left|m\right|}{m}|}^2---\left(15\right)$

From (9), zero Doppler slice of simo radar ambiguity function is:

${\mathrm{af}}_{\mathrm{simo}}(\mathrm{\&tau;},0)=\underset{m=-(m-1)}{\overset{m-1}{\mathrm{\&sigma;}}}(1-\frac{\left|m\right|}{m})\frac{w-|\mathrm{\&tau;}-\mathrm{mt}|}{w}---\left(16\right)$

τ=mt substitution (16) formula is obtained:

$a{f}_{\mathrm{simo}}(\mathrm{\&tau;},0){|}_{\mathrm{\&tau;}=\mathrm{mt}}=\underset{m=-(m-1)}{\overset{m-1}{\mathrm{\&sigma;}}}(1-\frac{\left|m\right|}{m})---\left(17\right)$

By (17) formula substitute into (15) Shi Ke get:

${\left|a{f}_{\mathrm{mimo}}(\mathrm{\&tau;},0)\right|}^2={\left|a{f}_{\mathrm{simo}}(\mathrm{\&tau;},0)\right|}_{\mathrm{\&tau;}=\mathrm{mt}}^2\&centerdot;f\left(k\right)---\left(18\right)$

Wherein:

$f\left(k\right)\text{=}\underset{k=-(n-1)}{\overset{n-1}{\mathrm{\&sigma;}}}(1-\frac{\left|k\right|}{n}){\left|\frac{\sin [\mathrm{\&pi;kpw}/t]}{\mathrm{\&pi;wkp}/t}\right|}^2---\left(19\right)$

(18) formula explanation, the time delay graing lobe of mimo radar is simo radar time delay graing lobe and weight function f (n, n') product Result.(19) formula shows, the variable of function f (n, n') is unrelated with simo radar time delay graing lobe variable τ and m in (19) formula, therefore, Weight function f (n, n') is to all time delay graing lobe af_simo(τ, 0) | τ=mt carries out identical weighting process, do not change central peak and The proportionate relationship of each graing lobe.Due to the amplitude no absolute sense of ambiguity function, after normalized, this weight function is permissible Ignore it may be assumed that

${\left|a{f}_{\mathrm{mimo}}(\mathrm{\&tau;},0)\right|}_{\mathrm{\&tau;}=\mathrm{mt}}^2={\left|a{f}_{\mathrm{simo}}(\mathrm{\&tau;},0)\right|}_{\mathrm{\&tau;}=\mathrm{mt}}^2---\left(20\right)$

From (20) formula, when meeting (13) formula, the position of time delay graing lobe and width in mimo radar zero Doppler slice Degree is identical with simo radar.Therefore, the nothing of incoherent mimo radar obscures time delay is still t.

The method of above-described embodiment passes through any two waveform in the frequency orthogonal sets of waveforms adjust incoherent mimo radar Frequency interval value so that incoherent mimo radar ambiguity function section no ambiguous Doppler be 1/t, extension keep orthogonal Incoherent mimo radar no confusion region area overcome in existing waveform design method for using n frequency orthogonal waveform Relevant mimo radar, its no ambiguous Doppler may narrow down to the 1/n of simo radar no ambiguous Doppler, leads to relevant mimo thunder Reach the 1/n that no confusion region area is reduced into simo radar no confusion region area, no ambiguous Doppler reduces and radar will be led to how general Strangle to obscure and mix aggravation with Doppler frequency, have a strong impact on radar velocity measurement and the problem of Doppler's clutter process performance.

Method according to embodiments of the present invention, enumerates two Application Examples.

Application Example one

According to the general design requirement of radar system, each parameter is initially set to: t=0.01 second, w=0.001 second, m= 9, n=3.Below with design parameter △ f of the present invention.

1) according to formula δ f mt=a, then δ f=a/mt=a/0.09；

2) according to formula δ f=p/t, then δ f=100p；

2) in make p=2, then δ f=200, and a=18.δ f=200 is exactly can by incoherent mimo radar no Confusion region area expands to the waveform parameter equal with simo.

Prior art be concerned with mimo radar sets of waveforms parameter as shown in Table 1,

Table one

t(s)	w(s)	m	n	δf(hz)	h	f(hz)
							0.01	0.001	9	3	133	1	33

The sets of waveforms parameter of Application Example one as shown in Table 2,

Table two

t(s)	w(s)	m	n	δf(hz)	p
						0.01	0.001	9	3	200	2

As shown in figures 2 a and 2b, incoherent mimo radar no ambiguous Doppler is about 33hz, incoherent mimo radar no mould Paste time delay is 0.01s.Fig. 2 shows that the no fuzzy time delay of relevant mimo radar is 0.01s.Therefore, non-determined by parameter in table one Relevant mimo radar no confusion region area is about 4/3, drops to the 1/3 of simo radar no confusion region area.This example shows exist Special waveform group makes the no ambiguous Doppler of relevant mimo radar drop to the 1/n of simo radar no ambiguous Doppler；And should The fuzzy time delay of the nothing of sets of waveforms is equal with the fuzzy time delay of the nothing of simo radar, leads under the no confusion region area of relevant mimo radar Drop to the 1/n of simo radar.

As best shown in figures 3 a and 3b, using the present embodiments relate to method for designing optimize after incoherent mimo radar No ambiguous Doppler reaches 100hz, the no ambiguous Doppler 1/t with corresponding simo radar.

Application Example two

According to the general design requirement of radar system, each parameter is initially set to: t=0.01 second, w=0.001 second, m= 9, n=3.Below with design parameter δ f of the present invention.

1) according to formula δ f mt=a, then δ f=a/mt=a/0.09；

2) according to formula δ f=p/t, then δ f=100p；

2) in make p=3, then δ f=300, and a=27.δ f=200 is exactly can by incoherent mimo radar no Confusion region area expands to the waveform parameter equal with simo.

Although being example purpose, have been disclosed for the preferred embodiments of the present invention, those skilled in the art will recognize Various improvement, increase and replacement are also possible, and therefore, the scope of the present invention should be not limited to above-described embodiment.

Claims (1)

1. a kind of incoherent mimo radar waveform method for designing towards the extension of no confusion region area is it is characterised in that include:

Set up the model of the frequency orthogonal sets of waveforms of several waveforms of inclusion of incoherent mimo radar, any two in sets of waveforms Waveform keeps orthogonal within the Coherent processing time；

In adjustment sets of waveforms, between two adjacent waveforms, frequency interval is so that incoherent mimo radar no ambiguous Doppler is 1/t, same When make the no fuzzy time delay of incoherent mimo radar be t, wherein t is the pulse repetition period；

The incoherent mimo radar mockup set up includes:

$x\left(t\right)=\underset{r=0}{\overset{m-1}{\&sigma;}}u(t-rt)---\left(1\right)$

$u\left(t\right)=\frac{1}{\sqrt{w}},-w/2<t<w/2---\left(2\right)$

s_n(t)=x (t) exp [j2 π (n δ f) t], n=1,2 ... n (3)

Wherein, x (t) is the baseband signal of train of pulse, and u (t) is rectangular pulse, and r is the numbering of certain pulse in train of pulse, and m is Pulse number in train of pulse；T is the pulse repetition period, and n is the frequency orthogonal ripple of the waveform of incoherent mimo radar chosen Shape group number；δ f is frequency interval, s between two adjacent waveforms in sets of waveforms_nT () is to detect waveform；W is pulse width；

Any two waveform in sets of waveforms is made to keep orthogonal within the Coherent processing time using following formula:

δ f mt=a (4)

Wherein δ f is frequency interval between two adjacent waveforms in sets of waveforms, and m is the pulse number in train of pulse, and t is pulse repetition In the cycle, a is any positive integer；

Using in following formula adjustment sets of waveforms between two adjacent waveforms frequency interval so that incoherent mimo radar no ambiguous Doppler For 1/t:

δ f=p/t (12)

Wherein δ f is frequency interval between two adjacent waveforms in sets of waveforms, and t is the pulse repetition period, and p is positive integer.