CN102121989A - Method for simultaneously measuring speed and distance of high-speed moving targets - Google Patents

Abstract

The invention discloses a method for simultaneously measuring speed and distance of high-speed moving targets based on single pulse echo signals, wherein the method comprises the following steps of: firstly configuring an expanded reference frequency spectrum, pulse compressing received echoes are pulsed compressing and detecting the targets in the pulse compression result; returning the extracted target areas to a frequency domain; obtaining Doppler shift of the targets according to the corresponding target pulse compression spectrum and a transmitted base band signal spectrum, measuring the radial speed of the targets; simultaneously, multiplying the target pulse compression spectrum by the expanded reference spectrum, decoding the pulse compression of target echoes; relatively shifting the target spectrum of which the pulse compression is decoded combining with the estimate to the Doppler shift of the targets so as to finish the pulse compression again according to the expanded reference spectrum, and obtaining the estimate of the target distance.

Description

A kind of speed of high-speed moving object and method of distance measured simultaneously

Technical field

The present invention relates to the radargrammetry technical field, more specifically, the present invention relates to a kind of be used for measuring the simultaneously speed of high-speed moving object and the method for distance.

Background technology

At present, the echo delay that radar system transmits by measurement obtains the range information of target, obtains the radial velocity of target with respect to radar by the Doppler frequency of measuring echo.For long-range radar, need long pulse to bring and obtain enough energy, to detect remote little target.Yet long pulse resolution on distance is relatively poor, can adopt frequency modulation or phase modulation to increase the spectrum width of long pulse in this case, thereby obtain the resolving power as short pulse, and this is called as " pulse compression ".

Also can adopt the continuous wave waveform in the radar, the continuous wave radar signal receives when emission, and then utilizes the Doppler shift of the echoed signal that is caused by target, measures the radial velocity of target.Simple continuous wave radar can not measuring distance.If the width long enough of radar pulse, and the Doppler shift of target is enough big in individual pulse is that the Doppler shift that target is detected on the basis also is possible with the frequency change.In order to be T at width _pIndividual pulse in detect Doppler shift, require to have at least in the pulse Doppler shift f of one-period usually _d, f in other words _dT _p＞1.

In many other radar systems, the radial component of speed can obtain according to range rate.The classical formulas of this measurement radial velocity is v _r=(R ₂-R ₁)/(T ₂-T ₁), promptly according to T ₁The time distance R ₁And T ₂The time distance R ₂Obtain.But using Doppler shift is the basic skills that obtains radial velocity, and it can carry out on the basis of single observation.Utilize the classical expression formula of Doppler shift, radial velocity v _rCan be expressed as v _r=λ f _d/ 2, wherein, λ represents wavelength.In the method for range rate, suppose that the time between twice range finding is identical with the doppler frequency measurement duration, then the precision of the radial velocity that obtains according to Doppler shift will be better than the precision of the radial velocity that obtains according to range rate far away.The precision of doppler frequency measurement is relevant with the duration, and Measuring Time is long more, and frequency accuracy is good more.In addition, wavelength is short more, realizes that the needed observation time of desired radial velocity precision is short more.In other words, under the situation of given observation time, wavelength is short more, and velocity accuracy is high more.

According to the fuzzy graph of chirp compressed waveform, in echoed signal, it is not to be actual distance that a big Doppler shift can cause shown distance, and this is called apart from Doppler and is coupled.Under many situations, the distance error that Doppler shift produces is smaller, and this is sustainable.If distance error is bigger, two distances of rising frequency modulation and the acquisition of decline frequency modulation are asked on average, can eliminate the influence of Doppler shift.In addition, there are a lot of radar systems that adopt the long pulse linear FM signal at present, are mainly used in the search and the tracking of high speed moving targets such as satellite or ballistic missile.As the Pave Paws of the U.S., transponder pulse is 16ms, and signal bandwidth reaches 26MHz.When adopting such long pulse signal to carry out the high-speed moving object range finding, must bring very big range finding deviation.Supposing the system emission linear FM signal bandwidth is 500kHz, Shi Kuanwei 2ms, carrier frequency 2.3GHz, the radial velocity of target is 4km/sec, then can produce the range finding deviation about 36.8km, the broadening 11% of pulse pressure main lobe meeting simultaneously, therefore, tackle above-mentioned Doppler coupling and be used, and compensation is made in its influence.

In a word, after the existing method that tests the speed simultaneously and find range by monopulse is separated the frequency modulation pulse compression to the wide-band linearity FM signal that receives, extract the speed and the range information of target by the Time-Frequency Analysis Method of complexity.These methods realize complicated, are applicable to the radar system of big bandwidth and high carrier frequency usually.Yet the radar system bandwidth that is used for long distance objective search and tracking is narrower, and existing method is difficult to provide the correct estimation of target range and speed.

Summary of the invention

For overcome existing test the speed simultaneously and distance-finding method in the defective of Analysis of Complex, low precision, when radar system adopted the long pulse linear FM signal, the present invention proposed a kind ofly to measure the distance of high-speed moving object and the method for speed simultaneously by the monopulse echo.

The present invention proposes a kind ofly measures the distance of high-speed moving object and the method for speed comprises simultaneously:

The echoed signal that step 10), the described high-speed moving object of reception transmit and produce for monopulse, structure expansion matched filtering function carries out pulse compression to described echoed signal, and the distance that obtains described high-speed moving object is to resolution;

Step 20), according to the distance of described high-speed moving object to resolution, detect target in the described echoed signal after pulse compression, extract the target area;

Step 30), the target area of being extracted is turned back to the signal spectrum space, obtain the pulse pressure spectrum of this target, the pulse pressure spectrum of this target is relevant with the spectrum that transmits, obtain the Doppler shift of target, obtain the radial velocity estimation of target with respect to radar;

Step 40), described target pulse pressure spectrum is separated pulse pressure, according to described target Doppler frequency shift estimation result, target is separated the pulse pressure spectrum carry out translation in the signal spectrum space; And pulse pressure again, thereby estimating target distance;

Wherein, to transmit be to have the long-pending linear FM signal of wide bandwidth when big to described monopulse.

Wherein, in the step 10), described monopulse transmits and is s (t)=g (t) exp (j2 π f _cT), wherein, g (t) is the base band linear FM signal, f _cBe carrier frequency, the frequency spectrum that g (t) is corresponding is G (f), and then the echo spectrum of described high-speed moving object is:

$S_r\left(f\right)\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f+f_{\mathrm{dop}\_n}}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{(f+f_{\mathrm{dop}\_n})}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f+f_c){\mathrm{\&tau;}}_n);$

Wherein, σ _nBe the amplitude of target, rect () is the unit gate signal, T _pBe pulse width, γ is a signal frequency modulation rate, B=γ T _pBe signal bandwidth, v _nBe the radial velocity of certain target with respect to radar, τ _nBe the delay of target actual distance correspondence, δ _{Cm_n}=1-2v _n/ c is the scale factor of certain target, and c is a propagation velocity of electromagnetic wave, f _{Dop_n}=2v _nf _c/ c is the Doppler frequency of certain target correspondence.

Wherein, in the step 10), the transmit extended reference frequency spectrum of identical frequency modulation rate of structure and described monopulse, the width of described extended reference frequency spectrum is that the bandwidth that described monopulse transmits adds the twice that the possible maximum Doppler of the above target is offset, and the expansion matched filtering function of described extended reference frequency spectrum correspondence is:

$G_{\mathrm{ext}}\left(f\right)=\mathrm{rect}\left(\frac{f}{B_{\mathrm{ext}}}\right)\exp (-j\frac{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}{\mathrm{\&gamma;}})$

Wherein, B _ExtBandwidth for described extended reference frequency spectrum.

Wherein, in the step 10), use described extended reference frequency spectrum to target echo signal frequency spectrum S _r(f) do pulse compression, the echoed signal after the matched filtering is

$s_m\left(t\right)=\&Integral;S_m\left(f\right)\exp \left(\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;ft}\right)\mathrm{df}$

$\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}B\sin c\left(B(t-{\mathrm{\&tau;}}_n-\frac{f_{\mathrm{dop}\_n}}{\mathrm{\&gamma;}})\right)\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{\mathrm{dop}\_n}t\}.$

$*\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n\}\exp \left\{j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{f_{\mathrm{dop}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\right\}$

Wherein, step 20) also comprise: detect target in the described echoed signal after pulse compression, cut apart, obtain the pulse pressure spectrum of described target, extract the target area detecting the gained target;

Wherein, by setting certain range gate size, detected target is split; For extraterrestrial target observation, the width of setpoint distance door is greater than 10 kilometers.

Wherein, step 30) in, target echo is turned back to the signal spectrum territory, and target-echo spectrum is relevant with the frequency spectrum that transmits, the skew of obtaining target-echo spectrum, its side-play amount is the Doppler frequency of target, obtains described target radial speed:

$\hat{v}=\mathrm{\&lambda;}{\hat{f}}_{\mathrm{dop}}/2$

Wherein,

Be target echo Doppler's estimated value, λ is a carrier wavelength.

Wherein, step 40 also comprises: according to the conjugate multiplication of described target-echo spectrum and extended reference frequency spectrum, this target-echo spectrum is separated pulse pressure; According to estimated target Doppler shift, carry out translation to separating pulse pressure spectrum, to through the target-echo spectrum of translation pulse pressure again, estimating target distance.

Wherein, step 40) in, the target echo that is extracted is transformed to frequency field, and it is separated pulse pressure respectively, obtain target-echo spectrum

$S_{\mathrm{dm}}\left(f\right)=S_m\left(f\right)G_{\mathrm{ext}}^{*}\left(f\right)G_{\mathrm{ext}}\left(f\right)\&ap;S_m\left(f\right);$

According to described target radial speed, the described target-echo spectrum of separating pulse pressure is carried out translation, obtain

$S_{\mathrm{dm}\_n}\left(f\right)\&ap;{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;f}{\mathrm{\&tau;}}_n)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n).$

Wherein, step 40) in, according to described target radial speed, will carry out pulse compression by matched filtering through separating the target-echo spectrum translation of pulse pressure, obtain the pulse pressure result of target echo, detect the distance estimations that obtains target by peak value.

Wherein, step 40) in, to being through separating pulse pressure and translation target-echo spectrum afterwards pulse pressure again, obtaining described pulse pressure result:

s _{rem_n}(t)＝∫S _{rem_n}(f)exp(j2πft)df

≈σ _n?B?sinc(B(t-τ _n))exp(-j2πf _cδ _{cm_n}τ _n)。

By using the present invention, can directly measure the radial velocity and the distance of high-speed moving object simultaneously according to the linear FM signal echo of monopulse.Method of the present invention is simple, is fit to adopt the remote high-speed target search and the tracking radar of long pulse signal form.

Description of drawings

Fig. 1 is the radial velocity curve of certain satellite with respect to radar station;

Fig. 2 is that radar system is observed synoptic diagram to high-speed moving object;

Fig. 3 is the process flow diagram of the method for measuring speed and distance simultaneously according to an embodiment of the invention;

Fig. 4 illustrates echo spectrum;

Fig. 5 illustrates the extended reference spectrum;

Fig. 6 illustrates extended filtering and traditional filtering result contrast;

Fig. 7 illustrates non-motion compensated and contrasts through the range finding after the motion compensation;

Fig. 8 illustrates the target spectrum and extracts the result; With

Range finding contrast after Fig. 9 illustrates the range finding result who ignores Doppler effect and passes through motion compensation.

Embodiment

Below in conjunction with the drawings and specific embodiments, a kind ofly measure the speed of high-speed moving object simultaneously and the method for distance is described further based on single pulse signal to provided by the invention.

Method of the present invention generally is applicable to high-speed moving object, for example target such as satellite, guided missile.Fig. 1 illustrates certain satellite target in the radial velocity of different observation times with respect to the ground radar research station, and as seen, this type of target has the feature of high-speed motion, and the radial velocity of ground radar observation point can reach 6～7km/s usually relatively.For the ground radar research station shown in Fig. 1, in one embodiment, the linear FM signal bandwidth of radar system emission is 500kHz, pulse length 2ms, and carrier frequency is 3.0GHz.This radar system is carried out the sampling of inphase/orthogonal (I/Q) binary channels to target echo, and sampling rate is 4MHz.

Fig. 2 illustrates the observed object synoptic diagram of this radar system, wherein, if contain three targets in certain echo, the distance of three targets is respectively 52km, 106km and 145km, the radial velocity of target correspondence is respectively-5km/s, 2km/s and 750m/s, and the relative amplitude of each target is respectively 1.5,1.2 and 0.78.Suppose that echo contains white Gaussian noise, whole signal to noise ratio (S/N ratio) is 6dB.In following description, use method of the present invention that these three targets are measured simultaneously, so that the measuring accuracy of method of the present invention to be described to method of the present invention.

Generally speaking, the present invention discloses a kind of method of carrying out the high-speed moving object range finding simultaneously and testing the speed based on single pulse signal, and wherein, it generally is to have the linear FM signal that big time wide bandwidth amasss that this monopulse transmits.Because Doppler effect, the echo spectrum of high-speed moving object has certain translation with respect to the transmitting baseband signal spectrum, and this translation must be measured the Doppler frequency that is target.

In one embodiment, for the radar system of monopulse s emission signal s (t), the echoed signal of target is expressed as:

$s_r\left(t\right)=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}s(t-{\mathrm{\&tau;}}_n\left(t\right))=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}s\left({\mathrm{\&delta;}}_{\mathrm{cm}\_n}(t-{\mathrm{\&tau;}}_n)\right)---\left(1\right)$

In the formula, σ _nBe the amplitude of each target, n=1,2,3 ... n, τ _n=2r _n/ c is the time delay of each target initial distance correspondence, δ _{Rm_n}=2v _n/ c is the relative velocity factor of each target, r _nAnd v _nBe respectively the initial distance and the radial velocity of each target, c is a propagation velocity of electromagnetic wave, is approximately 30000000m/s usually, δ _{Cm_n}=1-δ _{Rm_n}Scale factor for each echo.

The monopulse of radar system transmits and is expressed as:

s(t)＝g(t)exp(j2πf _ct) (2)

In the formula, f _cBe carrier frequency, g (t)=rect (t/T _p) exp (j π γ t ²) be the base band linear FM signal, rect () is the unit gate signal, T _pBe pulse width, γ is a signal frequency modulation rate.

When linear FM signal, wide bandwidth is long-pending bigger, ignores amplitude item and constant phase item, and the base-band signal spectrum approximation to function is:

$G\left(f\right)\&ap;\mathrm{rect}\left(\frac{f}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}{f}^2\}---\left(3\right)$

The target echo signal that receives further is expressed as:

$s_r\left(t\right)=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}g\left({\mathrm{\&delta;}}_{\mathrm{cm}\_n}(t-{\mathrm{\&tau;}}_n)\right)\exp \left(\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}(t-{\mathrm{\&tau;}}_n)\right)---\left(4\right)$

Target echo signal after coherent demodulation is:

$s_r\left(t\right)=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}g\left({\mathrm{\&delta;}}_{\mathrm{cm}\_n}(t-{\mathrm{\&tau;}}_n)\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{\mathrm{dop}\_n}(t-{\mathrm{\&tau;}}_n))\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&tau;}}_n)---\left(5\right)$

In the formula, f _{Dop_n}=f _cδ _{Rm_n}Doppler frequency for each target.

Ignore amplitude item and constant phase item, further obtain target-echo spectrum and be:

$S_r\left(f\right)=\&Integral;s_r\left(t\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;ft})\mathrm{dt}$

$\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f+f_{\mathrm{dop}\_n}}{B{\mathrm{\&delta;}}_{\mathrm{cm}\_n}}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{(f+f_{\mathrm{dop}\_n})}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f+f_c){\mathrm{\&tau;}}_n)---\left(6\right)$

Wherein, the relative bandwidth of radar system is B/f _c=1/6000, δ _{Cm_n}≈ 1, and then target-echo spectrum further is approximately:

$S_r\left(f\right)\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f+f_{\mathrm{dop}\_n}}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{(f+f_{\mathrm{dop}\_n})}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f+f_c){\mathrm{\&tau;}}_n)---\left(7\right)$

Can see that there is a skew in the target-echo spectrum envelope with respect to the spectrum envelope of reference signal, its side-play amount is the Doppler frequency f of target _{Dop_n}

Fig. 3 illustrates according to an embodiment of the invention the process flow diagram based on the method that tests the speed and find range of the high-speed moving object of monopulse echo.As shown in Figure 3, what this method was total comprises: receive the echoed signal that described high-speed moving object transmits and produces for monopulse, and structure expansion matched filtering function, butt joint is regained the ripple signal and is carried out pulse compression, to its matched filtering, obtain distance to target to differentiating (step 10); To resolution, in the echoed signal result of pulse compression, detect target according to the distance of described high-speed moving object, the target that detection obtains is cut apart, obtain the pulse pressure spectrum of each target respectively, and the target area is extracted (step 20); The target area of being extracted is turned back to the signal spectrum space, and the pulse pressure that obtains this target is composed, and this target pulse pressure spectrum is relevant with the spectrum that transmits, and obtains the Doppler shift of target, obtains target and estimates (step 30) with respect to the radial velocity of radar; At spectral space this target pulse pressure spectrum is separated pulse pressure,, this target is separated the pulse pressure spectrum carry out translation, and pulse pressure again, obtain the correct estimation (step 40) of target range according to the result of pulse pressure again according to target Doppler frequency shift estimation result.

Continuation describes in further detail the concrete steps of method of the present invention with reference to figure 3.In step 10, receive the echoed signal that described high-speed moving object transmits and produces for monopulse, to the echoed signal matched filtering that receives, the echoed signal frequency spectrum S of reception _r(f) as shown in Figure 4.Hypothetical target maximum radial speed is 20km/s, and corresponding maximum Doppler skew is 400kHz.Therefore, the bandwidth B of structure extended reference frequency spectrum _ExtBe 1.3MHz, as shown in Figure 5, can cover the scope of all possible target-echo spectrum.Then extended reference frequency spectrum (corresponding to expansion matched filtering function) is expressed as:

$G_{\mathrm{ext}}\left(f\right)=\mathrm{rect}\left(\frac{f}{B_{\mathrm{ext}}}\right)\exp (-j\frac{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}{\mathrm{\&gamma;}})---\left(8\right)$

According to the extended reference frequency spectrum to target echo signal S _r(f) do pulse compression, target-echo spectrum is after the matched filtering

$S_m\left(f\right)=S_r\left(f\right)G_{\mathrm{ext}}^{*}\left(f\right)$

$=\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f+f_{\mathrm{dop}\_n}}{B}\right)\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;f}[{\mathrm{\&tau;}}_n+\frac{f_{\mathrm{dop}\_n}}{\mathrm{\&gamma;}{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\left]\right\}*---\left(9\right)$

$\exp \{-j\frac{1-{\mathrm{\&delta;}}_{\mathrm{cm}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\frac{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}{\mathrm{\&gamma;}}\}\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{f_{\mathrm{dop}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&tau;}}_n)$

Find out that easily the influence of above-mentioned quadratic phase item can be ignored, then the pulse pressure result through the target-echo spectrum after the matched filtering is

$s_m\left(t\right)=\&Integral;S_m\left(f\right)\exp \left(\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;ft}\right)\mathrm{df}$

$\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}B\sin c\left(B(t-{\mathrm{\&tau;}}_n-\frac{f_{\mathrm{dop}\_n}}{\mathrm{\&gamma;}})\right)\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{\mathrm{dop}\_n}t\}---\left(10\right)$

$*\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n\}\exp \left\{j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{f_{\mathrm{dop}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\right\}$

Obviously, through the expansion matched filtering, the pulse pressure amplitude of target echo does not descend because of Doppler effect, thereby can not impact target detection.And if the direct spectrum that transmits that adopts is carried out matched filtering to target echo, then the pulse pressure amplitude can descend, and echo main lobe meeting broadening, as shown in Figure 6.The high-speed motion of target can produce considerable influence to the range finding of target, can not proofread and correct by extended filtering; If do not do correction, the deviation of then finding range is

$\#R_n=\frac{c}{2}\frac{f_{\mathrm{dop}\_n}}{\mathrm{\&gamma;}}=\frac{v_n{f}_c}{\mathrm{\&gamma;}}---\left(11\right)$

When not carrying out motion estimation and compensation, the range finding result who obtains three targets is respectively 112.01km as shown in Figure 7,82.01km and 136.01km, and corresponding range deviation is respectively-60km 24km and 9km.

In step 20, adopt the algorithm of target detection of present existing various maturations to detect target, and detected target is split one by one.In one embodiment, by setting certain range gate size, detected target is split; Wherein, for extraterrestrial target observation, setpoint distance gate-width degree is greater than 10 kilometers.

In step 30, the target echo signal that splits is transformed into frequency field, as shown in Figure 8.One by one that the target-echo spectrum that splits is relevant with the spectrum that transmits, obtain the skew of target-echo spectrum with respect to the extended reference frequency spectrum, this side-play amount is the Doppler frequency of target, thus the radial velocity that obtains target is estimated:

${\hat{v}}_n=\mathrm{\&lambda;}{\hat{f}}_{\mathrm{dop}\_n}/2---\left(12\right)$

Wherein,

Be the Doppler frequency of target, λ is a carrier wavelength.

Wherein, the radial velocity of gained target is estimated to be respectively-5029.3m/s 2026.4m/s and 781.3m/s.

In step 40, each target echo signal after the pulse pressure of being extracted is transformed to frequency field, and it is separated pulse pressure respectively, obtain:

$S_{\mathrm{dm}}\left(f\right)=S_m\left(f\right)G_{\mathrm{ext}}^{*}\left(f\right)G_{\mathrm{ext}}\left(f\right)\&ap;S_m\left(f\right)---\left(13\right)$

According to the target velocity estimated result, the frequency spectrum of above-mentioned process being separated pulse pressure carries out translation, obtains

$S_{\mathrm{dm}\_n}\left(f\right)\&ap;{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;f}{\mathrm{\&tau;}}_n)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n)---\left(14\right)$

In step 50,, obtain through separating pulse pressure and translation target-echo spectrum afterwards pulse pressure again

$S_{\mathrm{rem}\_n}\left(f\right)=S_{\mathrm{dm}\_n}\left(f\right)G_{\mathrm{ext}}^{*}\left(f\right)$

$\&ap;{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f}{B}\right)\exp \{-j\frac{1-{\mathrm{\&delta;}}_{\mathrm{cm}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}{f}^2\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;f}{\mathrm{\&tau;}}_n)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HSA00000158803300022.png,HSA00000158803300031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n)---\left(14\right)$

In the above-mentioned expression formula (14), the influence of quadratic phase item can be ignored, thereby obtain the pulse pressure result is

s _{rem_n}(t)＝∫S _{rem_n}(f)exp(j2πft)df

≈σ _n?B?sinc(B(t-τ _n))exp(-j2πf _cδ _{cm_n}τ _n) (15)

According to above-mentioned pulse pressure result's envelope, can obtain correct target position information.In the present embodiment, three measured target ranges are respectively 51.6km, 106.275km and 145.35km, as shown in Figure 9.Because the theoretical resolution that the signal that is adopted in the present case brings is 300 meters, target location provided by the invention measuring method has good precision.

As seen, the present invention provides a kind of implementation of finding range simultaneously and testing the speed based on the high-speed moving object of monopulse echo, comparatively accurate target velocity and range observation have been obtained, by the extended filtering method, resolution of ranging to three targets is respectively 300 meters, 300 meters and 337.5 meters.

It should be noted that at last, above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, and on using, can extend to other modification, variation, application and embodiment, think that simultaneously all such modifications, variation, application, embodiment are within the spirit and scope of the present invention.

Claims (10)

1. measure the distance of high-speed moving object simultaneously and the method for speed comprises for one kind:

The echoed signal that step 10), the described high-speed moving object of reception transmit and produce for monopulse, structure expansion matched filtering function carries out pulse compression to described echoed signal, and the distance that obtains described high-speed moving object is to resolution;

Step 20), according to the distance of described high-speed moving object to resolution, detect target in the described echoed signal after pulse compression, extract the target area;

Step 30), the target area of being extracted is turned back to the signal spectrum space, according to the pulse pressure spectrum of this target that the pulse pressure spectrum of this target is relevant with the spectrum that transmits, obtain the Doppler shift of target, obtain the radial velocity estimation of target with respect to radar;

Step 40), in the signal spectrum space to the general pulse pressure of separating of described target pulse pressure, according to described target Doppler frequency shift estimation result, the pulse pressure spectrum of separating of target is carried out translation, and pulse pressure again, the estimating target distance;

Wherein, to transmit be to have the long-pending linear FM signal of wide bandwidth when big to described monopulse.

2. the process of claim 1 wherein that in the step 10), described monopulse transmits and is s (t)=g (t) exp (j2 π f _cT), wherein, g (t) is the base band linear FM signal, f _cBe carrier frequency, the frequency spectrum that g (t) is corresponding is G (f), and then the echo spectrum of described high-speed moving object is:

$S_r\left(f\right)\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f+f_{\mathrm{dop}\_n}}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{{(f+f_{\mathrm{dop}\_n})}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-j2\mathrm{\&pi;}(f+f_c){\mathrm{\&tau;}}_n);$

Wherein, σ _nBe the amplitude of target, rect () is the unit gate signal, T _pBe pulse width, γ is a signal frequency modulation rate, B=γ T _pBe signal bandwidth, f _{Dop_n}=2v _nf _c/ c is the Doppler frequency of target correspondence, v _nBe the radial velocity of target with respect to radar, δ _{Cm_n}=1-2v _n/ c is the scale factor of target, and c is a propagation velocity of electromagnetic wave, τ _nDelay for target actual distance correspondence.

3. the method for claim 2, wherein, in the step 10), the transmit extended reference frequency spectrum of identical frequency modulation rate of structure and described monopulse, the width of described extended reference frequency spectrum is that the bandwidth that described monopulse transmits adds the twice that the possible maximum Doppler of the above target is offset, and the expansion matched filtering function of described extended reference frequency spectrum correspondence is:

$G_{\mathrm{ext}}\left(f\right)=\mathrm{rect}\left(\frac{f}{B_{\mathrm{ext}}}\right)\exp (-j\frac{\mathrm{\&pi;}{f}^2}{\mathrm{\&gamma;}})$

Wherein, B _ExtBandwidth for described extended reference frequency spectrum.

4. the method for claim 3 wherein, in the step 10), uses described extended reference frequency spectrum to target echo signal frequency spectrum S _r(f) do pulse compression, the echoed signal after the matched filtering is

$s_m\left(t\right)=\&Integral;S_m\left(f\right)\exp \left(j2\mathrm{\&pi;ft}\right)\mathrm{df}$

$\&ap;\underset{n}{\mathrm{\&Sigma;}}{\mathrm{\&sigma;}}_{n}B\sin c\left(B(t-{\mathrm{\&tau;}}_n-\frac{f_{\mathrm{dop}\_n}}{\mathrm{\&gamma;}{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2})\right)\exp \{-j2\mathrm{\&pi;}{f}_{\mathrm{dop}\_n}t\}.$

$*\exp \{-j2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n\}\exp \left\{j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{f_{\mathrm{dop}\_n}^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\right\}$

5. the process of claim 1 wherein step 20) also comprise: detect target in the described echoed signal after pulse compression, cut apart, obtain the pulse pressure spectrum of described target, extract the target area detecting the gained target;

Wherein, by setting certain range gate size, detected target is split; For extraterrestrial target observation, the width of setpoint distance door is greater than 10 kilometers.

6. the method for claim 3, wherein, step 30) in, target echo is turned back to the signal spectrum territory, and target-echo spectrum is relevant with the transmitting baseband signal spectrum, the skew of obtaining target-echo spectrum, its side-play amount is the Doppler frequency of target, obtains described target radial speed:

$\hat{v}=\mathrm{\&lambda;}{\hat{f}}_{\mathrm{dop}}/2$

Wherein, Be target echo Doppler's estimated value, λ is a carrier wavelength.

7. the method for claim 3, wherein, step 40 also comprises: according to the conjugate multiplication of described target-echo spectrum and extended reference frequency spectrum, this target-echo spectrum has been separated pulse pressure according to estimated target Doppler shift, carry out translation to separating the pulse pressure spectrum, to through the target-echo spectrum of translation pulse pressure again, estimating target distance.

8. the method for claim 7, wherein, step 40) in, the target echo that is extracted is transformed to frequency field, and it is separated pulse pressure respectively, obtain target-echo spectrum

$S_{\mathrm{dm}}\left(f\right)=S_m\left(f\right)G_{\mathrm{ext}}^{*}\left(f\right)G_{\mathrm{ext}}\left(f\right)\&ap;S_m\left(f\right);$

According to described target radial speed, the described target-echo spectrum of separating pulse pressure is carried out translation, obtain

$S_{\mathrm{dm}\_n}\left(f\right)\&ap;{\mathrm{\&sigma;}}_n\mathrm{rect}\left(\frac{f}{B}\right)\exp \{-j\frac{\mathrm{\&pi;}}{\mathrm{\&gamma;}}\frac{f^2}{{\mathrm{\&delta;}}_{\mathrm{cm}\_n}^2}\}\exp (-j2\mathrm{\&pi;f}{\mathrm{\&tau;}}_n)\exp (-j2\mathrm{\&pi;}{f}_c{\mathrm{\&delta;}}_{\mathrm{cm}\_n}{\mathrm{\&tau;}}_n).$

9. the method for claim 7, wherein, step 40) in, according to described target radial speed, will carry out pulse compression by matched filtering through separating the target-echo spectrum translation of pulse pressure, obtain the pulse pressure result of target echo, detect the distance estimations that obtains target by peak value.

10. the method for claim 9, wherein, step 40), to being through separating the target-echo spectrum pulse pressure again after pulse pressure and the translation, obtaining described pulse pressure result:

s _{rem_n}(t)＝∫S _{rem_n}(f)exp(j2πft)df

≈σ _n?B?sinc(B(t-τ _n))exp(-j2πf _cδ _{cm_n}τ _n)。

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