CN103163511A - Stepped frequency signal phase compensation method for digital array radar - Google Patents

Abstract

The invention discloses a stepped frequency signal phase compensation method for digital array radar, and belongs to the field of digital signal processing. The method includes the steps: firstly, emitting a stepped frequency signal sub-pulse by each channel of the digital array radar to acquire video echo signals; secondly, selecting the phase of the maximum point of the video echo signal of each sub-pulse in the corresponding channel to perform linear fitting, compensating a phase value at a specified moment to realize zero deviation between a fit straight slope and an ideal slope, acquiring video echo compensation factors and performing IFFT (inverse fast Fourier transformation) for the compensated signals to output high resolution range profiles; thirdly, compensating the phase of a peak point of the high resolution range profile of each channel and enabling the phase difference between peak points of the range profiles of the channels at the same distance to be consistent with an ideal phase difference to acquire range profile compensation factors; and fourthly, applying the acquired video echo compensation factors and the acquired range profile compensation factors to the signal processing procedure of the digital array radar. The method is applicable to signal processing of the digital array radar.

Description

The compensation method of a kind of Digital Array Radar frequency step signal phase

Technical field

The invention belongs to the Radar Signal Processing Technology field, be specially adapted to target with high precision distance and measurement of angle in the frequency modulation stepping radar system.

Background technology

The frequency modulation stairstep signal is a kind of radar signal with high resolution capacity, the radar pulse of the linear saltus step of carrier frequency, arteries and veins internal linear frequency modulation between one group of arteries and veins of its emission, by each subpulse echo is carried out in arteries and veins inverse Fourier transform (IFFT) between pulse compression and arteries and veins process obtain target apart from high resolution picture.The frequency modulation stairstep signal has replaced simple pulse in the frequency step signal with the linear frequency modulation subpulse, therefore overcome the contradiction between radar horizon and monopulse range resolution, can reduce umber of pulse under the constant condition of the resolving power of keeping at a distance again, improve data transfer rate, reduce the requirement of system being processed bandwidth and sampling rate.

Digital Array Radar for present widespread use, there are a plurality of passages in it, if the frequency modulation stairstep signal is applied to Digital Array Radar, not only the interior phase place of each passage all can cause the situation of each frequency phase nonlinear of frequency modulation stairstep signal, and has the inconsistent situation of a plurality of interchannel phase error characteristic.

Because frequency phase nonlinear in passage can bring degradation problem under one-dimensional range profile main lobe broadening, amplitude, and then cause the one-dimensional distance image distortion of target.The inconsistent compound direction figure beam position that can cause of interchannel phase error characteristic is offset, and secondary lobe raises, and affects the angle measurement quality.

In order to address this problem, just must select suitable time point to carry out phase compensation, existing Phase Compensation for the frequency step signal only carries out linear phase for single pass situation to be proofreaied and correct, but do not consider Digital Array Radar exists in multichannel situation proofread and correct afterwards its each channel linear characteristic curve slope is inconsistent that angle measurement is brought error.

Summary of the invention

In view of this, the invention provides the compensation method of a kind of Digital Array Radar frequency step signal phase, can eliminate the impact that interchannel phase error is brought to the frequency modulation stairstep signal in Digital Array Radar is used, thereby improve range finding and angle measurement accuracy.

For achieving the above object, technical scheme of the present invention is: the method comprises the steps:

The first step, Digital Array Radar have a plurality of passages, and each passage is comprised of 1 bay and No. 1 receiver; Each passage is launched the pulse of a string frequency step signal subspace, and receives the target echo signal of each subpulse; Target echo signal is processed, obtained the video echo signal of each subpulse;

Second step, obtain the video echo compensating factor of each passage, be specially:

For each passage, in this passage, choose a peaked point of corresponding phase in each sampled point of the video echo signal of each subpulse as the phase sample point of this subpulse, carry out for phase sample point and the corresponding phase value thereof of each subpulse the phase-fitting straight line that linear fit obtains working as prepass;

Choose the slope of phase-fitting straight line of a passage as standard value, the slope of adjusting each channel phases fitting a straight line is consistent with standard value;

For each passage, in phase-fitting straight line after adjustment, obtain value corresponding to phase sample point, and in the phase-fitting straight line before adjustment, obtain equally value corresponding to phase sample point, difference both is as the video echo compensating factor of this passage, uses this compensating factor to compensate to the phase sample point of this passage video echo signal, and the signal after compensation carries out inverse Fourier transform IFFT output High Range Resolution;

The 3rd goes on foot, obtains the Range Profile compensating factor of each passage, is specially:

To each passage High Range Resolution after the second step compensation, the phase place of getting peak point compensates, and offset is by the phase differential of the peak point of each passage High Range Resolution on same distance

And the difference between desired phase is poor is determined, after compensation

And the difference between desired phase is poor is 0, records one group of offset of a plurality of passages of corresponding Digital Array Radar, is the Range Profile compensating factor;

The 4th step, in the signal processing of Digital Array Radar, after obtaining video echo signal, use described video echo compensating factor that the phase place of each sampled point of video echo signal is compensated; Video echo signal after compensation is carried out IFFT, obtain High Range Resolution, use described Range Profile compensating factor that the phase place of each passage High Range Resolution peak point is compensated.

Further, in the first step, the signal of passage emission is a string linear frequency modulation Chirp subpulse.

Beneficial effect:

Utilize compensation process of the present invention to be compensated the factor, not only can synthesize phase error compensation in passage before high-resolution to linear frequency modulation stepping echoed signal, and synthetic high resolution picture is carried out the interchannel phase error compensation, can form in theory target without broadening, main lobe amplitude without the real one dimension High Range Resolution that descends; Solve the impact on range finding and angle measurement that brings due to phase error in passage and interchannel phase error, be particularly useful for frequency modulation stepping radar to the high-acruracy survey of angle.

Description of drawings

Fig. 1 is the present invention actual signal processing flow figure that implements on engineering;

Fig. 2 is each passage High Range Resolution comparison diagram before and after compensation;

Fig. 3 is the compound direction figure comparison diagram before and after compensation.

Embodiment

Below in conjunction with the accompanying drawing embodiment that develops simultaneously, describe the present invention.

As shown in Figure 1, this method comprises the steps:

The first step, Digital Array Radar have a plurality of passages, and each passage is comprised of 1 bay and No. 1 receiver; Each passage is launched the pulse of a string frequency step signal subspace, and receives the target echo signal of each subpulse; Target echo signal is processed, obtained the video echo signal of each subpulse.The processing of wherein target echo signal being carried out comprises the sampling of signal.

Narrate as example take linear frequency modulation Chirp subpulse string in the present embodiment, the first step specifically comprises the steps:

Step 101 supposes that Digital Array Radar has M passage, and each passage is comprised of 1 bay and No. 1 receiver, for passage m, and its bay Z _mTransmit and be the pulse of a string frequency step signal subspace, 1≤m≤M.

The frequency step signal that adopts in the present embodiment is linear frequency modulation Chirp subpulse string, this Chirp subpulse string carries out the linear saltus step of carrier frequency, to its general mathematics model of carrying out obtaining after sampling processing linear frequency modulation Chirp subpulse, the Chirp subpulse is expressed as following formula:

$x\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r}{T_p}\right)\exp \left\{j\right[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f})t+\mathrm{\&pi;K}{(t-{\mathrm{iT}}_r)}^2\left]\right\},---\left(1\right)$

t∈(0，NT _r)

Wherein, T _pBe subpulse width, T _rBe the pulse repetition time, f ₀Be the carrier component of each subpulse, Δ f is carrier frequency increment between arteries and veins, f ₀+ i Δ f is the centre frequency of the carrier frequency of i+1 subpulse, and the i value is 0,1,2...N-1, and N is subpulse number in the arteries and veins group, and K is the chirp rate of subpulse.

Step 102 transmits after the target reflection, bay Z _mRespective antenna receiver J _mReceiving target echo signal is frequency step subpulse time-delay τ _m(t) signal.

In the present embodiment, target echo signal Chirp subpulse time-delay τ _m(t) signal is expressed as:

$x_m\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right)}{T_p}\right)$

$\exp \left\{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\right[({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f})(t-{\mathrm{\&tau;}}_m\left(t\right))+\frac{1}{2}K{(t-{\mathrm{\&tau;}}_m\left(t\right)-{\mathrm{iT}}_r)}^2\left]\right\},---\left(2\right)$

t∈(0，NT _r)

τ wherein _m(t)=2R/c-(m-1) dsin θ/c, c is the light velocity, R is target and bay Z _mDistance, θ is the angle between target and passage normal, d is the distance between each adjacent antenna array element, wherein compare with 2R/c, (m-1) dsin θ/c magnitude than I to ignore.

Step 103 is carried out Frequency mixing processing with target echo signal and the coherent local oscillation signal of passage m, obtains video echo.In the present embodiment, the coherent local oscillation signal that uses is:

$y\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r}{T_r}\right)\exp \{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f})\&CenterDot;t]\},---\left(3\right)$

t∈(0，NT _r)

Formula (2) and coherent local oscillation signal are carried out the video echo that mixing obtains is:

${x_m}^{\&prime;}\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right)}{T_p}\right)\&CenterDot;\exp \left\{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\right[-({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f}){\mathrm{\&tau;}}_m\left(t\right)+\frac{1}{2}K{(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}^2\left]\right\},---\left(4\right)$

t∈(0，NT _r)

Due to phase error in passage, it is not desirable linear straight line that the phase place of each pulse maximum point changes, but fluctuates up and down at straight line.φ _iDifference for each impulse phase and ideal value.Formula (4) becomes:

$s_m\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\mathrm{rect}\left[\frac{t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right)}{T_p}\right]\&CenterDot;\exp \left(\mathrm{j\&pi;K}{(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}^2\right)---\left(5\right)$

$\&CenterDot;\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0{\mathrm{\&tau;}}_m\left(t\right))\&CenterDot;\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;i\&Delta;}{\mathrm{f\&tau;}}_m\left(t\right))\&CenterDot;\exp \left({-\mathrm{j\&phi;}}_i\right)$

For the simple pulse of frequency step signal, each step after the video echo signal that obtains can directly apply to, and the frequency step signal in the present embodiment is linear frequency modulation Chirp subpulse string, needs video echo signal is carried out pulse compression.

Wherein pulse compression is based on matched filtering theory, is a kind of processing form to linear FM signal, and group pulse linear FM signal is:

$\mathrm{rect}\left|\frac{t}{T_p}\right|\exp \left({\mathrm{j\&pi;Kt}}^2\right)---\left(6\right)$

The Output rusults of its pulse compression should be:

$\mathrm{rect}\left|\frac{t}{T_p}\right|\sqrt{{\mathrm{<figure-callout\; id="2"\; label="KT\; p"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">KT</figure-callout>}}_p^{}}\frac{\sin \left({\mathrm{\&pi;KT}}_{p}t\right)}{{\mathrm{\&pi;KT}}_{p}t}\exp (-j{\mathrm{\&pi;Kt}}^2)\exp (\mathrm{j\&pi;}/4)---\left(7\right)$

In the present embodiment, formula (5) is carried out obtaining after pulse compression:

${s_m}^{\&prime;}\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\sqrt{{\mathrm{KT}}_P}\&CenterDot;\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right)}{T_p}\right)\&CenterDot;\frac{\sin {\mathrm{\&pi;KT}}_p(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}{{\mathrm{\&pi;KT}}_p(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}---\left(8\right)$

$\&CenterDot;\exp (\mathrm{j\&pi;}/4)\exp \{-\mathrm{j\&pi;K}(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m{\left(t\right)}^2\}\&CenterDot;\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f}){\mathrm{\&tau;}}_m\left(t\right)\}\&CenterDot;\exp \left({-\mathrm{j\&phi;}}_i\right)$

Second step, obtain the video echo compensating factor of each passage, be specially:

For each passage, in this passage, choose a peaked point of corresponding phase in each sampled point of the video echo signal of each subpulse as the phase sample point of this subpulse, carry out for phase sample point and the corresponding phase value thereof of each subpulse the phase-fitting straight line that linear fit obtains working as prepass;

Choose the slope of phase-fitting straight line of a passage as standard value, the slope of adjusting each channel phases fitting a straight line is consistent with standard value;

For each passage, in phase-fitting straight line after adjustment, obtain value corresponding to phase sample point, and in the phase-fitting straight line before adjustment, obtain equally value corresponding to phase sample point, difference both is as the video echo compensating factor of this passage, all uses this compensating factor to compensate to each sampled point of this passage video echo signal, and the signal after compensation carries out inverse Fourier transform IFFT output High Range Resolution.

In the present embodiment, second step specifically comprises the steps

Step 201, for passage m, in all sampling instant points of the video echo signal of each subpulse, choose the peaked point of corresponding phase as the phase sample point of this pulse, because the subpulse number is N, passage m has N phase sample point, and N phase sample point and corresponding phase value thereof are carried out the phase-fitting straight line that linear fit obtains passage m.Owing to using the Chirp subpulse to process, get the phase place of the maximum of points of the video echo signal after pulse compression in the present embodiment, it is carried out linear fit.

Eliminated the frequency phase nonlinear that single channel internal channel phase error causes this moment.

In the present embodiment, by formula (8) as can be known, desirable linear phase straight line should be with 2 π Δ f τ _m(t) be slope, take i as variable, and because φ _iIntroducing, cause phase place to fluctuate up and down at ideal line, so can there be the deviation with desirable linear phase straight line in the slope after match, suppose for passage m, after pulse compression is carried out in each pulse that obtains, maximum of points match phase place straight line can be expressed as:

Φ _mFor maximum of points phase place after pulse compression, k are carried out in each pulse _mBe the slope of match phase place straight line, b _mBe the intercept of match phase place straight line, β _mPoor for the slope of passage m and desirable slope value.

Due in formula (8) because of deviation exp (j φ _i) introducing, the slope of the linear phase straight line after match is 2 π Δ f (τ _m(t)+β _m), formula (8) becomes:

${s_m}^{\&prime;}\left(t\right)=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\sqrt{{\mathrm{KT}}_P}\&CenterDot;\mathrm{rect}\left(\frac{t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right)}{T_p}\right)\&CenterDot;\frac{\sin \mathrm{\&pi;}{\mathrm{KT}}_p(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}{{\mathrm{\&pi;KT}}_p(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m\left(t\right))}---\left(10\right)$

$\&CenterDot;\exp (\mathrm{j\&pi;}/4)\exp \{-\mathrm{j\&pi;K}(t-{\mathrm{iT}}_r-{\mathrm{\&tau;}}_m{\left(t\right)}^2\}\&CenterDot;\exp \{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f})[{\mathrm{\&tau;}}_m\left(t\right)+{\mathrm{\&beta;}}_m\left]\right\}$

Eliminated the frequency phase nonlinear that single channel internal channel phase error causes this moment.

Step 202, the present embodiment are used the Chirp subpulse, and the video echo signal of getting after pulse compression is that formula (10) is processed.

The present embodiment verifies as calculated, for obtaining pulse echo signal maximum of points phase place, should choose and constantly is t=iT _r+ τ _m(t), can sample thus after the echo of i pulse be output as:

${s_c}^{\&prime;}\left(i\right)=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="KT\; p"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">KT</figure-callout>}}_p^{}}\&CenterDot;\exp (\mathrm{j\&pi;}/4)\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f})({\mathrm{\&tau;}}_m\left(t\right)+{\mathrm{\&beta;}}_m)]---\left(11\right)$

Make the slope deviation β of each channel phases fitting a straight line _m=0 obtains:

${s_c}^{\&prime;}\left(i\right)=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="KT\; p"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">KT</figure-callout>}}_p^{}}\&CenterDot;\exp (\mathrm{j\&pi;}/4)\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\mathrm{i\&Delta;f}){\mathrm{\&tau;}}_m\left(t\right)]---\left(12\right)$

β ₁～β _mAs the video echo compensating factor.Following formula (12) is the video echo signal of compensation t i pulse constantly afterwards, following formula is carried out IFFT output High Range Resolution be:

${\left|y\left(l\right)\right|}_m=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="KT\; p"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">KT</figure-callout>}}_p^{}}\&CenterDot;\exp (-\mathrm{j\&pi;}/4)\&CenterDot;\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&pi;<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\&CenterDot;{\mathrm{\&tau;}}_m\left(t\right))\&CenterDot;\left|\frac{\sin \mathrm{\&pi;}(l-\mathrm{N\&Delta;f}\&CenterDot;(2R/c))}{N\sin \frac{\mathrm{\&pi;}}{N}(l-\mathrm{N\&Delta;f}\&CenterDot;(2R/c))}\right|---\left(13\right)$

Wherein l=0,1 ..., N-1.

All carry out the compensation of above-mentioned steps and carry out the High Range Resolution that IFFT obtains each passage for each passage.

If each channel phases straight slope is different, corresponding distance is different, and in synthetic antenna directional diagram process, needs the upper extraction of same distance point phase information, if so the inconsistent meeting of each channel phases straight slope the synthetic antenna directional diagram is caused difficulty.After adjustment phase-fitting straight slope is consistent, has eliminated and introduced the error of synthetic high resolution picture, thereby eliminated the error of compound direction figure, can improve angle measurement accuracy.

Can find out, second step has carried out the phase compensation of two places altogether, one place carries out match for the maximum of points phase place of each pulse video echo signal in passage in step 201 to get linear straight line, has eliminated the frequency phase nonlinear that single channel internal channel phase error causes herein; Another place is in step 202, and the slope of adjusting each channel phases fitting a straight line is consistent, and each sampled point of video echo signal in passage is all compensated, and has eliminated the inconsistent impact that the synthetic antenna directional diagram is caused of each channel phases straight slope herein.

The 3rd goes on foot, obtains the Range Profile compensating factor of each passage, is specially:

To each passage High Range Resolution after the second step compensation, the phase place of getting peak point compensates, and offset is by the phase differential of the peak point of each passage High Range Resolution on same distance

And the difference between desired phase is poor is determined, after compensation

And the difference between desired phase is poor is 0, records one group of offset of a plurality of passages of corresponding Digital Array Radar, is the Range Profile compensating factor.

In the present embodiment, for Digital Array Radar, between each adjacency channel, desired phase is poor is:

λ is wavelength.

Actual in the frequency step Digital Array Radar, because the interchannel characteristic is inconsistent, namely each channel phases error is different, can impact follow-up angle measurement and compound direction figure.If each interchannel characteristic is inconsistent, each passage is introduced phase error _m, have

$\left|y_{\mathrm{cm}}\left(l\right)\right|=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="KT\; p"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">KT</figure-callout>}}_p^{}}\&CenterDot;\exp (-\mathrm{j\&pi;}/4)\&CenterDot;\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00002888452500011.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&pi;<figure-callout\; id="0"\; label="f"\; filenames="HDA00002888452500022.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\&CenterDot;{\mathrm{\&tau;}}_m\left(t\right))$

$\&CenterDot;\left|\frac{\sin \mathrm{\&pi;}(l-\mathrm{N\&Delta;f}\&CenterDot;2R/c)}{N\sin \frac{\mathrm{\&pi;}}{N}(l-\mathrm{N\&Delta;f}\&CenterDot;2R/c)}\right|\&CenterDot;\exp \left({\mathrm{j\&alpha;}}_m\right)---\left(15\right)$

When this step is carried out, the calibration object can be placed on normal direction, the desired phase of each passage echo is poor

Be 0, obtain High Range Resolution after compensation according to the first step～3rd step, the phase place of peak point is compensated, making the phase difference φ between each passage is 0, obtains compensating factor this moment.Use this compensating factor can compensate preferably for interchannel inconsistency.

Can find out, the 3rd step was carried out single compensation, can eliminate well interchannel inconsistency, therefore used this method to carry out three compensation to the frequency step signal, reached interchannel phase error in passage and had all obtained compensation preferably.

The 4th step, in the signal processing of Digital Array Radar, after obtaining video echo signal, use described video echo compensating factor that the phase place of video echo signal is compensated; Video echo signal after compensation is carried out using described Range Profile compensating factor that the phase place of each passage High Range Resolution peak point is compensated after inverse Fourier transform IFFT obtains the High Range Resolution of each passage.

The present embodiment adopts 4 passage Digital Array Radar, has 4 bays.Corresponding No. 4 receivers of 4 bays, target is at the about 50m place of normal direction.Be illustrated in figure 2 as each passage High Range Resolution comparison diagram of compensation front and back, it is the compound direction figure comparison diagram of compensation front and back as Fig. 3, by Fig. 2 and Fig. 3, measured data imaging processing result is compared, can find that the measured data result shows high-resolution imaging result after compensation and the angle measurement result result when not compensating far away.Its reason is in technical solution of the present invention, reaches interchannel phase error in passage and has obtained compensation preferably.

Below in conjunction with drawings and Examples, technical solution of the present invention is done further explanation.

In sum, these are only preferred embodiment of the present invention, is not for limiting protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (2)

1. Digital Array Radar frequency step signal phase compensation method is characterized in that, comprises the steps:

The first step, Digital Array Radar have a plurality of passages, and each passage is comprised of 1 bay and No. 1 receiver; Each passage is launched the pulse of a string frequency step signal subspace, and receives the target echo signal of each subpulse; Target echo signal is processed, obtained the video echo signal of each subpulse;

Second step, obtain the video echo compensating factor of each passage, be specially:

For each passage, in this passage, choose a peaked point of corresponding phase in each sampled point of the video echo signal of each subpulse as the phase sample point of this subpulse, carry out for phase sample point and the corresponding phase value thereof of each subpulse the phase-fitting straight line that linear fit obtains working as prepass;

Choose the slope of phase-fitting straight line of a passage as standard value, the slope of adjusting each channel phases fitting a straight line is consistent with standard value;

For each passage, in phase-fitting straight line after adjustment, obtain value corresponding to phase sample point, and in the phase-fitting straight line before adjustment, obtain equally value corresponding to phase sample point, difference both is as the video echo compensating factor of this passage, uses this compensating factor to compensate to the phase sample point of this passage video echo signal, and the signal after compensation carries out inverse Fourier transform IFFT output High Range Resolution;

The 3rd goes on foot, obtains the Range Profile compensating factor of each passage, is specially:

To each passage High Range Resolution after the second step compensation, the phase place of getting peak point compensates, and offset is by the phase differential of the peak point of each passage High Range Resolution on same distance And the difference between desired phase is poor is determined, after compensation

And the difference between desired phase is poor is 0, records one group of offset of a plurality of passages of corresponding Digital Array Radar, is the Range Profile compensating factor;

The 4th step, in the signal processing of Digital Array Radar, after obtaining video echo signal, use described video echo compensating factor that the phase place of each sampled point of video echo signal is compensated; Video echo signal after compensation is carried out IFFT, obtain High Range Resolution, use described Range Profile compensating factor that the phase place of each passage High Range Resolution peak point is compensated.

2. a kind of Digital Array Radar frequency step signal phase as claimed in claim 1 compensation method is characterized in that, in the first step, the signal of passage emission is a string linear frequency modulation Chirp subpulse.

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