CN114966686B - Bank-ship bistatic high-frequency ground wave radar motion compensation method - Google Patents
Bank-ship bistatic high-frequency ground wave radar motion compensation method Download PDFInfo
- Publication number
- CN114966686B CN114966686B CN202210582487.3A CN202210582487A CN114966686B CN 114966686 B CN114966686 B CN 114966686B CN 202210582487 A CN202210582487 A CN 202210582487A CN 114966686 B CN114966686 B CN 114966686B
- Authority
- CN
- China
- Prior art keywords
- ship
- motion
- target
- distance
- vessel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000033001 locomotion Effects 0.000 title claims abstract description 158
- 238000000034 method Methods 0.000 title claims abstract description 50
- 230000006835 compression Effects 0.000 claims abstract description 23
- 238000007906 compression Methods 0.000 claims abstract description 23
- 230000010355 oscillation Effects 0.000 claims abstract description 20
- 238000012545 processing Methods 0.000 claims abstract description 12
- 238000012937 correction Methods 0.000 claims abstract description 6
- 230000005012 migration Effects 0.000 claims abstract description 6
- 238000013508 migration Methods 0.000 claims abstract description 6
- 230000003534 oscillatory effect Effects 0.000 claims description 22
- 238000001514 detection method Methods 0.000 claims description 10
- 230000004044 response Effects 0.000 claims description 8
- 108090000623 proteins and genes Proteins 0.000 claims description 7
- 229910052704 radon Inorganic materials 0.000 claims description 7
- SYUHGPGVQRZVTB-UHFFFAOYSA-N radon atom Chemical compound [Rn] SYUHGPGVQRZVTB-UHFFFAOYSA-N 0.000 claims description 7
- 230000009471 action Effects 0.000 claims description 6
- 238000003672 processing method Methods 0.000 claims description 4
- 230000009466 transformation Effects 0.000 claims description 4
- 238000009825 accumulation Methods 0.000 claims description 3
- 238000001228 spectrum Methods 0.000 description 7
- CLOMYZFHNHFSIQ-UHFFFAOYSA-N clonixin Chemical compound CC1=C(Cl)C=CC=C1NC1=NC=CC=C1C(O)=O CLOMYZFHNHFSIQ-UHFFFAOYSA-N 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 241000669618 Nothes Species 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000035899 viability Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
- G01S13/937—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of marine craft
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
- G01S7/415—Identification of targets based on measurements of movement associated with the target
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Radar, Positioning & Navigation (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Ocean & Marine Engineering (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
A bank-ship bistatic high-frequency ground wave radar motion compensation method belongs to the technical field of radar signal processing. The invention aims to solve the problem that the target azimuth defocuses when the synthetic aperture is processed due to the six-degree-of-freedom motion of a ship. The ship-borne platform receives the echo signals, and performs range compression and range migration correction on the echo signals; motion compensation is carried out on the processed echo signals, the oscillation motion parameters of the received ship platform are measured through inertial navigation data, the oscillation motion parameters of the target ship are obtained through estimation of a differential evolution algorithm, and motion compensation is carried out on the echo signals after the obtained total oscillation motion parameters are obtained; and finally, carrying out azimuth compression according to the Doppler parameters estimated from the echo signals. The method is used for motion compensation when the high-frequency ground wave radar adopts a synthetic aperture signal processing mode.
Description
Technical Field
The invention belongs to the technical field of radar signal processing, and relates to a ship detection method.
Background
High Frequency Surface Wave Radar (HFSWR) can realize sea beyond visual range detection by utilizing the diffraction and propagation characteristics of vertically polarized electromagnetic waves on the sea Surface, but the traditional shore-based Radar has the characteristics of difficult site selection, poor flexibility and maneuverability and weak viability. In order to solve the problems, the HFSWR based on the ship-based platform is generated, the ship can be appointed to rapidly drive to an appointed target sea area to complete a monitoring task on the marine environment while inheriting the advantages of the shore-based HFSWR, the maneuverability is strong, and the method has a wide application value in the aspect of detecting the sea surface and the low-altitude-motion target. However, because the space of the ship-borne platform is limited, the array aperture is small, the azimuth resolution is low, the estimation precision is poor, in order to improve the azimuth resolution, a synthetic aperture signal processing method can be adopted, a virtual large aperture is synthesized by utilizing the motion of the ship-borne platform, the azimuth resolution is improved, targets which cannot be distinguished before can be distinguished, the target detection and sea state remote sensing capabilities are further improved, and the method has important significance for improving the radar detection performance of the system.
Under a ship-borne synthetic aperture system, the Doppler spectrum of a radar echo signal is influenced by ship motion, when the ship moves with six degrees of freedom under the action of sea waves, the Doppler spectrum of the echo signal has not only linear modulation but also nonlinear modulation, the nonlinear modulation can be approximately the superposition of a plurality of sine modulations, and the amplitude and the period of the nonlinear modulation also change along with the change of sea states. Because the doppler frequency modulation rate of the carrier-borne HFSWR is low, the amplitude of the sinusoidal modulation is much larger than the modulation frequency even under low sea conditions, and thus the sinusoidal modulation can cause mismatching of the azimuth compression function during synthetic aperture processing, which leads to defocusing of the target and affects the detection performance. Therefore, motion compensation of the echo signals before azimuth compression is required.
At present, synthetic aperture signal processing methods are rarely applied to high-frequency ground wave radars in China, and most of existing ship-based HFSWR motion compensation related researches only consider the influence of six-degree-of-freedom motion of a platform on a target echo signal Doppler spectrum, do not consider that six-degree-of-freedom motion also exists when a target is a ship, and the six-degree-of-freedom motion can also generate similar influence on the Doppler spectrum of the echo signal. In addition, the previous research only considers the influence of six-degree-of-freedom motion on the Doppler spectrum of the echo signal, but does not consider the influence of the six-degree-of-freedom motion on the time spectrum of the echo signal.
Disclosure of Invention
The invention aims to solve the problem of defocusing of a target position during synthetic aperture processing caused by six-degree-of-freedom motion of a ship.
A bank-ship bistatic high-frequency ground wave radar motion compensation method comprises the steps that a bank-based transmitter transmits radar signals to a target sea area, electromagnetic waves are diffracted and spread along the sea surface after the radar signals irradiate a target ship, and the target detection is realized through the method after the ship receives echo signals; the method comprises the following steps:
step 1, considering that a ship acts under the action of oscillatory motion, establishing a distance equation R (t) of a high-frequency ground wave radar in a shore-based transmitting-ship-borne receiving mode a ) And obtaining the time domain (t) in the fast time-azimuth slow time domain r ,t a ) Target ship echo signal s received by internal ship-based platform r (t r ,t a )；t a Representing the corresponding slow time, t, of the ship's motion r The time is fast;
step 2, echo signal s r (t r ,t a ) Performing distance compression processing to match distance with function h 1 (t r ) The distance compression is realized by multiplying the echo signal in a frequency domain;
step 3, performing range migration correction on the echo signal subjected to range compression to obtain a corrected echo signal s rcmc (t r ,t a )；
Step 4, the distance R (t) a ) Corresponding motion error Δ R (t) a ) Resolved into an oscillatory motion component Δ R of the target vessel st (t a ) And receiving an oscillatory motion component Δ R of the vessel sr (t a ) (ii) a Obtaining Δ R from inertial navigation data sr (t a ) The delta R is estimated by a differential evolution algorithm st (t a ) Further, the position motion error DeltaR (t) is obtained a )；
Then to the echo signal s rcmc (t r ,t a ) And (3) performing motion compensation: firstly, s is rcmc (t r ,t a ) Multiplication by H in the distance frequency domain MC1 (f r ,t a ) To compensate for Δ R (t) a ) The resulting envelope shift; multiplying the compensated signal by a phase compensation function H MC2 (t a ) (ii) a Performing the second step of compensation;
wherein j represents an imaginary number; c represents the speed of light; f. of r Is a fast time t r A corresponding distance frequency domain after Fourier transform; λ is the radar operating wavelength;
further obtaining echo signals after motion compensation;
and 5, performing azimuth compression on the echo signals subjected to motion compensation according to Doppler parameters estimated from the echo signals to obtain distance and azimuth information of the target, so as to realize detection of the ship target.
Further characterized in that the distance equation is
wherein, t a Representing the corresponding slow time of ship motion, R tc Represents t a Distance, R, between transmitter and target vessel at time =0 rc Represents t a =0 time of reception of distance, v, of ship and target ship r To receive the speed of movement, v, of the vessel t Is the speed of motion of the target vessel,
is its angle, alpha, relative to the speed of motion of the receiving vessel t Is the azimuth angle of the target relative to the transmitter, beta is the target relative to the receiverThe azimuth angle of the vessel; u. of 1r (t a )、u 2r (t a ) For receiving surging and swaying motions of ships u 1t (t a )、u 2t (t a ) The motion is surging and swaying motion of a target ship and is sinusoidal motion.
Further, the receiving ship surging and swaying motion is as follows:
wherein A is 1r 、A 2r For respective corresponding amplitudes, ω 1r 、ω 2r For respective angular frequencies, Δ φ 1r 、Δφ 2r The initial phases are respectively corresponding;
the surging and swaying motion of the target ship is as follows:
wherein A is 1t 、A 2t For respective corresponding amplitude, ω 1t 、ω 2t For respective angular frequencies, Δ φ 1t 、Δφ 2t Are the respective corresponding initial phases.
Further, distance equation R (t) a ) In addition to
And
all the other terms belong to an extra distance term delta R (t) caused by the oscillating motion of the ship under the influence of sea waves a ) I.e. motion error; Δ R (t) a ) The following were used:
wherein, Δ R st (t a )＝-u 1t (t a )[sinα t +sinβ]-u 2t (t a )[cosα t +cosβ]Is the oscillatory motion component, Δ R, of the target vessel sr (t a )＝u 1r (t a )sinβ+u 2r (t a ) cos β is the oscillatory motion component of the receiving vessel.
Further, the Doppler frequency of the echo signal of the target ship under the condition of considering the oscillation motion of the ship is
Wherein u' 1t (t a ) Is u 1t (t a ) First derivative of (a), u ″) 1t (t a ) Is u 1t (t a ) The remaining derivative variables represent the same;
the Doppler frequency of an echo signal of a target ship under the condition of ship oscillation motion is not considered.
Further, in the range fast time-azimuth slow time domain (t) r ,t a ) Target ship echo signal s received by internal ship-based platform r (t r ,t a ) As follows
In the formula, A 0 Is any complex constant; w is a r (t r ) A rectangular window is adopted as a distance window function; w is a a (t a ) A rectangular window is adopted as an azimuth window function; λ is the radar operating wavelength; c represents the speed of light; k is a radical of r Frequency modulation is carried out on the signal; t is t r The time is fast; t is t a Is a slow time; j represents an imaginary number.
Further, a distance matching function h 1 (t r )＝w r (t r )exp{-jπk r t r 2 }。
Further, when the range migration correction is performed on the echo signal after the range compression in the step 3, a phase term is multiplied by the range frequency domain
I.e. obtaining a corrected echo signal s rcmc (t r ,t a )。
Further, the delta R is estimated by a differential evolution algorithm st (t a ) Comprises the following steps:
step 4.1, firstly, analyzing Wigner-Ville distribution of target ship echo signals, and obtaining Doppler center frequency and modulation frequency through Radon transformation;
step 4.2, estimating by adopting a differential evolution algorithm, and constructing the ideal azimuth focusing peak response AML of the target according to the Doppler center frequency and the modulation frequency estimated in the step 4.1 ideal ＝sinc(B a t a ) In which B is a ＝k a T ac For Doppler bandwidth, T, of echo signals ac For accumulation time, sinc (-) is the sine function;
the fitness function was chosen to be f = PF (AML-AML) ideal ) 2 Wherein AML is the actual azimuth focusing peak response, PF is the penalty function;
setting the gene dimension of each individual as 6, and respectively corresponding to the amplitude, period and phase of the swaying and surging motion of the target ship; obtaining an individual with the minimum fitness value as an optimal individual by adopting a differential evolution algorithm, and estimating the oscillatory motion component delta R of the target ship according to corresponding information in individual genes st (t a )。
Furthermore, when the azimuth compression is carried out according to the Doppler parameters estimated from the echo signals, the echo signals after the motion compensation are multiplied by an azimuth compression matching function H in a Doppler frequency domain 2 (f a )
Wherein, f a Is the Doppler frequency domain, f ac Is the Doppler center frequency, k a For Doppler frequency modulation, these parameters are estimated by the Wigner-Ville distribution and Radon transform.
The invention has the beneficial effects that: the invention provides a target ship oscillation parameter estimation method based on a differential evolution algorithm, aiming at the problem of azimuth defocusing caused by six-degree-of-freedom motion of a ship in a ship-borne HFSWR scene by adopting a synthetic aperture processing method.
Drawings
FIG. 1 is a schematic flow chart of a method for compensating motion of a carrier-based high-frequency ground wave radar based on differential evolution.
FIG. 2 is a flow chart of a differential evolution algorithm.
Figure 3 is a schematic diagram of the transmitter, receiving vessel and target vessel geometric positional relationship.
FIG. 4 (a) is a comparison of target azimuth profiles without motion compensation of echo signals at three sea states and with the method of the present invention; FIG. 4 (b) is a comparison of target azimuth profiles without motion compensation of echo signals in the fifth sea state and with the motion compensation of the method of the present invention.
FIG. 5 (a) is a comparison of the target azimuth profile without motion compensation and with the motion compensation of the present invention method in the five-level sea state and with the signal-to-noise ratio of the echo signal of 0 dB; FIG. 5 (b) is a comparison of target azimuth profiles without motion compensation and with motion compensation by the method of the present invention in the five-level sea state and with an echo signal to noise ratio of-5 dB; FIG. 5 (c) is a comparison of target azimuth profiles without motion compensation and with motion compensation using the method of the present invention at sea state five and echo signal SNR of-10 dB.
Detailed Description
The invention establishes a land-ship bistatic high-frequency ground wave radar target echo signal model under the condition of considering that a target ship and a receiving ship both have six-degree-of-freedom motion, and provides a motion compensation method for estimating oscillation parameters of the target ship based on a differential evolution algorithm. Before describing the invention, firstly, the working process of the radar under the system of the invention is described, a shore-based transmitter transmits radar signals to a target sea area, electromagnetic waves are diffracted and spread along the sea surface after irradiating a target ship, and a nearby receiving ship which does uniform linear motion receives echo signals to realize target detection through the method of the invention.
The first embodiment is as follows: the present embodiment is described in connection with figure 1,
the shore-ship bistatic high-frequency ground wave radar motion compensation method in the embodiment comprises the following steps: .
Step 1, a shore-based transmitter transmits radar signals to a target sea area, electromagnetic waves are diffracted and spread along the sea surface after the radar signals irradiate a target ship, and nearby receiving ships which do uniform linear motion receive echo signals;
under the action of sea waves, a ship has six-degree-of-freedom motion which can be divided into three-dimensional oscillation motion (surging, swaying and heaving) and swing motion (swaying, pitching and yawing), oscillation motion errors can directly generate three-dimensional displacement, doppler parameters of echo signals are influenced, and compensation is usually required. While the rolling motion requires separate discussions for the receiving vessel and the target vessel:
for receiving ships, the influence mainly comprises the deviation of the antenna beam direction and the distance change from the antenna to a target, and regarding the problem of the antenna beam direction change, an antenna stabilizing platform can be adopted, the antenna is placed on the multi-axis stabilizing platform to isolate the influence of angle swing on the antenna beam, and the distance change from the target to the receiving antenna caused by swing motion can be obtained through inertial navigation data and compensated.
For the target ship influenced by the swinging motion, because the resolution of the carrier HFSWR is poor, the ship target can be displayed as a point target on the radar with the system generally, and the point target is reasonable as the central position of the target ship, so that the central position of the ship cannot be changed in position under the action of the swinging motion. Therefore, the invention mainly considers the influence of the oscillation motion error on the carrier-borne HFSWR.
Considering the ship under the action of oscillatory motion, establishing a distance equation R (t) of a high-frequency ground wave radar in a shore-based transmitting-ship-borne receiving mode a ) According to FIG. 3, the expression of the distance equation is
Wherein, t a Representing the corresponding slow time of ship motion, R tc Represents t a Distance, R, between transmitter and target vessel at time =0 rc Represents t a =0 time of reception of distance, v, of ship and target ship r For receiving the speed of movement, v, of the vessel t Is the speed of motion of the target vessel,
is its angle of incidence, alpha, relative to the speed of motion of the receiving vessel t Is the azimuth of the target relative to the transmitter, β is the azimuth of the target relative to the receiving vessel; u. of 1r (t a )、u 2r (t a )、u 3r (t a ) For receiving surging, swaying and heaving motions of ships u 1t (t a )、u 2t (t a )、u 3t (t a ) Assuming that the target ship moves in a sine mode in surging, swaying and heaving modes, the specific expression is as follows:
wherein A is i′j′ 、ω i′j′ 、Δφ i′j′ I '=1,2,3, j' = r, t for amplitude, angular frequency and initial phase respectively corresponding to the three components;
regarding the influence of the heave motion, the phase difference caused before and after considering the heave motion and ignoring the heave motion is much less than pi/4, so the heave component u in the distance equation can be ignored 3r (t a ) And u 3t (t a ). The distance equation is expanded by a binomial mode, and high-order terms are ignored, so that the distance equation is
Wherein,
the distance of the target to the transmitter without the oscillatory motion error,
the distance from the target to the receiving ship when no oscillation motion error exists.
In the distance expression, except
And
all the other terms belong to an extra distance term delta R (t) caused by the oscillatory motion of the ship under the influence of sea waves a ) I.e. motion error, for Δ R (t) a ) Make the following decomposition
Wherein, Δ R st (t a )＝-u 1t (t a )[sinα t +sinβ]-u 2t (t a )[cosα t +cosβ]Is the oscillatory motion component, Δ R, of the target vessel sr (t a )＝u 1r (t a )sinβ+u 2r (t a ) cos β is the oscillatory motion component of the receiving vessel.
Suppose there is noThe Doppler frequency of the echo signal of the target ship under the condition of considering the oscillatory motion of the ship is
The Doppler frequency after the introduction of the oscillatory motion is
Wherein u is 1 ′ t (t a ) Is u 1t (t a ) First derivative of (u) 1 ″ t (t a ) Is u 1t (t a ) The remaining derivative variables are as defined above.
It can be seen that under the assumed conditions of the present invention, besides linear modulation, the doppler spectrum of the target ship echo signal also has sinusoidal modulation caused by six-degree-of-freedom motion of the target ship and the receiving ship.
Target ship echo signal s received by ship-based platform r (t r ,t a ) In the range fast time-azimuth slow time domain (t) r ,t a ) Can be expressed as
In the formula, A 0 Is any complex constant; w is a r (t r ) A rectangular window is adopted as a distance window function; w is a a (t a ) A rectangular window is adopted as an azimuth window function; λ is the radar operating wavelength; c represents the speed of light; k is a radical of formula r Frequency modulation is carried out on the signal; t is t r The time is fast; t is t a Is a slow time; j represents an imaginary number.
Step 2, the echo signal shown in the formula (6) is subjected to distance compression processing, and a distance matching function h 1 (t r ) Is composed of
h 1 (t r )＝w r (t r )exp{-jπk r t r 2 } (7)
H is to be 1 (t r ) And (3) multiplying the echo signal in a frequency domain to realize distance compression:
wherein, f r Is a fast time t r The corresponding distance frequency domain after the Fourier transform,
represents a pair t r The Fourier transform is carried out, and the Fourier transform is carried out,
represents a pair of f r And performing inverse Fourier transform.
Step 3, echo signal s processed in step 2 is processed rc (t r ,t a ) Performing range migration correction by multiplying a phase term in a range frequency domain
Obtaining a corrected echo signal s rcmc (t r ,t a )。
Step 4, echo signal s processed in step 3 is processed rcmc (t r ,t a ) Performing motion compensation, in particular oscillatory motion Δ R (t) to the ship a ) Compensation is carried out, and the component can be decomposed into an oscillating motion component Delta R of the target ship st (t a ) And receiving an oscillatory motion component Δ R of the vessel sr (t a ) Wherein Δ R sr (t a ) Can be obtained by inertial navigation data, and the delta R of the non-cooperative target st (t a ) The method can not be achieved, and the method is obtained by differential evolution algorithm estimation, and specifically comprises the following steps:
step 4.1, mentioned in the above analysis, under the condition that the ship has six-degree-of-freedom motion, the doppler domain of the echo signal has linear modulation and 4 sine wave modulations, and the central frequency and the modulation frequency of the linear modulation need to be estimated from the doppler domain, the method adopts the Wigner-Ville distribution and combines Radon transformation to obtain the echo signal, firstly, the Wigner-Ville distribution of the target ship echo signal is analyzed, the main frequency information influencing the Wigner-Ville distribution is analyzed, the amplitude and the phase of the sine wave modulation are temporarily ignored in the derivation process, and the phase characteristics of the target ship echo signal can be simplified and expressed as that the target ship echo signal can be simply expressed as
Wherein f is ac Is the Doppler center frequency; k is a radical of a Adjusting the frequency for Doppler; f. of i (i = 1-4) corresponds to the frequency of the sine wave modulation, specifically to the frequencies of the sine waves of the swaying and surging of the target ship, and the swaying and surging of the receiving ship, and the frequencies are respectively f 1 、f 2 、f 3 、f 4 。
Then its Wigner-Ville distribution is
Wherein n is i (i =1 to 4) is an integer,
is n i The order of the Bessel function, δ (f), is an impulse function.
It can be seen that the Wigner-Ville distribution is given by f (t) a )＝f ac +k a t a Is centered at a frequency difference of
A plurality of straight lines of (a), and f (t) a )＝f ac +k a t a Has the largest amplitude, i.e. has the strongest energy. According to the characteristic, the Doppler center frequency and the modulation frequency can be obtained through Radon transformation.
And 4.2, estimating the motion error of the non-cooperative target based on the main lobe fitting of the ideal azimuth of the target. Aiming at the problem that the oscillation motion parameters of the non-cooperative target are unknown, the method adopts a differential evolution algorithm to estimate, and a plurality of parameters are estimated according to the step 4.1The center frequency and the modulation frequency of the puler are used for constructing the AML with the ideal azimuth focusing peak value response of the target ideal ＝sinc(B a t a ) In which B is a ＝k a T ac For Doppler bandwidth, T, of echo signals ac For accumulation time, sinc (. Cndot.) is a sine function.
The fitness function was chosen to be f = PF (AML-AML) ideal ) 2 The AML is the actual azimuth focusing peak response, the PF is a penalty function, the weight is larger at the position where the peak response is larger, the weight distribution is the same as that of a sinc function, the amplitude is lower than-40 dB, and the magnitude of the penalty function is 0. It should be noted that there is a certain estimation error in the estimated doppler center frequency, but the relative error does not exceed 3%, and it is necessary to envelope align the ideal azimuth peak focus response, penalty function and current azimuth compression output according to the main lobe peak position before calculating the fitness each time. Referring to the processing flow of fig. 2, by adopting a differential evolution algorithm, the number of individuals in each generation of population is set to be 60, the gene dimension of each individual is set to be 6, the gene dimensions respectively correspond to the amplitude, the period and the phase of the swaying motion and the surging motion of the target ship, the individual with the minimum fitness value in the population is the optimal individual after 300 iterations, and then the oscillation motion component delta R of the target ship is estimated according to the corresponding information in the individual genes st (t a )。
Obtaining the position motion error delta R (t) a ) Then, compensation is carried out in two steps, and the first step of compensation is to carry out compensation on the signal s processed in the step 3 rcmc (t r ,t a ) Multiplication by H in the distance frequency domain MC1 (f r ,t a ) To compensate for Δ R (t) a ) The resulting movement of the envelope is such that,
the second step of compensation is to multiply the signal compensated in the first step by a phase compensation function H MC2 (t a ) The expression is
After motion compensation, the distance term in the phase of the echo signal is changed from the form of formula (1)
Therefore, the azimuth compression matching function in the step 5 can be completely matched, and the problem of azimuth defocusing after synthetic aperture processing caused by ship oscillation motion is solved.
Wherein f is a Is the Doppler frequency domain, f ac Is the Doppler center frequency, k a For Doppler frequency modulation, these parameters are estimated by the Wigner-Ville distribution and Radon transform.
So far, the synthetic aperture processing and the motion compensation processing of the carrier-borne HFSWR echo signal are basically completed.
Examples
The invention mainly adopts a simulation experiment method to verify the feasibility of the scheme, and the simulation experiment is carried out by referring to the specific implementation steps, wherein the simulation parameters are shown in tables 1 and 2, the table 1 is the geometric parameters of the ship-borne HFSWR system, and the table 2 is the geometric parameters of the ship-borne platform
TABLE 1
TABLE 2
The results of not performing motion compensation and performing motion compensation by using the method of the present invention are compared, respectively, fig. 4 (a) is a comparison of target azimuth profiles of not performing motion compensation on echo signals in a three-level sea state and performing motion compensation by using the method of the present invention, fig. 4 (b) is a comparison of target azimuth profiles of not performing motion compensation on echo signals in a three-level sea state and performing motion compensation by using the method of the present invention, table 3 is a theoretical value of surging and swaying parameters of a target ship in a three-level sea state and an estimated value of the method of the present invention, and table 4 is a theoretical value of surging and swaying parameters of a target ship in a five-level sea state and an estimated value of the method of the present invention.
TABLE 3
TABLE 4
In order to verify the reliability of the method, the effectiveness of the method is assumed to be respectively considered when the signal to noise ratio is 0dB, -5dB and-10 dB under the background of five-level sea state and white Gaussian noise, fig. 5 (a) is the comparison of target azimuth profiles without motion compensation and with the method of the invention when the signal to noise ratio of echo signals is 0dB, fig. 5 (b) is the comparison of target azimuth profiles without motion compensation and with the method of the invention when the signal to noise ratio of echo signals is-5 dB, and fig. 5 (c) is the comparison of target azimuth profiles without motion compensation and with the method of the invention when the signal to noise ratio of echo signals is-10 dB. According to simulation results, the method can effectively estimate the oscillation error of the target ship when the signal-to-noise ratio is greater than-10 dB, and carry out motion compensation on the echo signal.
In conclusion, the simulation experiment verifies the correctness, the effectiveness and the reliability of the method.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications be considered as within the spirit and scope of the appended claims.
Claims (10)
1. A bank-ship bistatic high-frequency ground wave radar motion compensation method is characterized in that a bank-based transmitter transmits radar signals to a target sea area, electromagnetic waves irradiate to a target ship and then are diffracted and spread along the sea surface, and the target detection is realized through the method after receiving echo signals received by the ship, and the method comprises the following steps:
step 1, considering that a ship acts under the action of oscillatory motion, establishing a distance equation R (t) of a high-frequency ground wave radar in a shore-based transmitting-ship-based receiving mode a ) And obtaining the time domain (t) in the fast time-azimuth slow time domain r ,t a ) Target ship echo signal s received by internal ship-based platform r (t r ,t a )；t a Representing the slow time, t, corresponding to the ship motion r The time is fast;
step 2, echo signal s r (t r ,t a ) Performing distance compression processing to match distance with function h 1 (t r ) The distance compression is realized by multiplying the echo signals in a frequency domain;
step 3, performing range migration correction on the echo signal after range compression to obtain a corrected echo signal s rcmc (t r ,t a )；
Step 4, the distance R (t) a ) Corresponding motion error Δ R (t) a ) Resolved into an oscillatory motion component Δ R of the target vessel st (t a ) And receiving an oscillatory motion component Δ R of the ship sr (t a ) (ii) a Obtaining Δ R from inertial navigation data sr (t a ) The delta R is estimated by a differential evolution algorithm st (t a ) Further obtainPosition motion error Δ R (t) a )；
Then to the echo signal s rcmc (t r ,t a ) And (3) performing motion compensation: firstly, s is rcmc (t r ,t a ) Multiplication by H in the distance frequency domain MC1 (f r ,t a ) To compensate for Δ R (t) a ) The resulting envelope shift; multiplying the compensated signal by a phase compensation function H MC2 (t a ) (ii) a Performing the second step of compensation;
wherein j represents an imaginary number; c represents the speed of light; f. of r Is a fast time t r The corresponding distance frequency domain after Fourier transform; lambda is the radar operating wavelength;
then obtaining echo signals after motion compensation;
and 5, performing azimuth compression on the echo signals subjected to motion compensation according to Doppler parameters estimated from the echo signals to obtain distance and azimuth information of the target, so as to realize detection of the ship target.
2. The method for motion compensation of the shore-vessel bistatic high-frequency ground wave radar as claimed in claim 1, wherein the distance equation is
wherein, t a Representing the corresponding slow time of ship motion, R tc Represents t a Distance, R, between transmitter and target vessel at time =0 rc Denotes t a =0 time of reception of distance, v, of ship and target ship r To receive the speed of movement, v, of the vessel t Is the speed of motion of the target vessel,
is its angle, alpha, relative to the speed of motion of the receiving vessel t Is the azimuth of the target relative to the transmitter, β is the azimuth of the target relative to the receiving vessel; u. of 1r (t a )、u 2r (t a ) For receiving surging and swaying motions of ships u 1t (t a )、u 2t (t a ) The surging and swaying motions of the target ship are assumed to be sinusoidal motions.
3. The shore-vessel bistatic high-frequency ground wave radar motion compensation method according to claim 2, wherein the receiving vessel surging and swaying motions are as follows:
wherein, A 1r 、A 2r For respective corresponding amplitude, ω 1r 、ω 2r For respective angular frequencies, Δ φ 1r 、Δφ 2r The initial phases are respectively corresponding;
the surging and swaying motion of the target ship is as follows:
wherein, A 1t 、A 2t For respective corresponding amplitudes, ω 1t 、ω 2t For respective angular frequencies, Δ φ 1t 、Δφ 2t Are the respective corresponding initial phases.
4. The method for compensating motion of a ship-to-ship bistatic high-frequency ground wave radar as claimed in claim 3, wherein the distance equation R (t) is a ) In addition to
And
all the other terms belong to an extra distance term delta R (t) caused by the oscillating motion of the ship under the influence of sea waves a ) I.e. motion error; Δ R (t) a ) The following:
wherein, Δ R st (t a )＝-u 1t (t a )[sinα t +sinβ]-u 2t (t a )[cosα t +cosβ]Is the oscillatory motion component, Δ R, of the target vessel sr (t a )＝u 1r (t a )sinβ+u 2r (t a ) cos β is the oscillatory motion component of the receiving vessel.
5. The shore-vessel bistatic high-frequency ground wave radar motion compensation method according to claim 4, wherein the Doppler frequency of the echo signal of the target vessel under the condition of ship oscillation motion is considered as
Wherein u is 1 ′ t (t a ) Is u 1t (t a ) First derivative of (u) 1 ″ t (t a ) Is u 1t (t a ) The remaining derivative variables represent the same;
the Doppler frequency of an echo signal of a target ship under the condition of ship oscillation motion is not considered.
6. The shore-vessel bistatic high-frequency ground wave radar motion compensation method according to claim 5, wherein a synthetic aperture signal processing method is adopted to perform fast-azimuth slow time domain (t) in distance time r ,t a ) Target ship echo signal s received by internal ship-based platform r (t r ,t a ) As follows
In the formula, A 0 Is any complex constant; w is a r (t r ) A rectangular window is adopted as a distance window function; w is a a (t a ) A rectangular window is adopted as an azimuth window function; λ is the radar operating wavelength; c represents the speed of light; k is a radical of r Frequency modulation is carried out on the signals; t is t r The time is fast; t is t a Is a slow time; j represents an imaginary number.
7. The shore-vessel bistatic high-frequency ground wave radar motion compensation method according to claim 6, wherein the distance matching function h is 1 (t r )＝w r (t r )exp{-jπk r t r 2 }。
8. The method for motion compensation of the shore-vessel bistatic high-frequency ground wave radar as claimed in claim 7, wherein in the step 3, when performing range migration correction on the range-compressed echo signal, a phase term is multiplied by a range frequency domain
I.e. obtaining a corrected echo signal s rcmc (t r ,t a )。
9. The shore-vessel bistatic high-frequency ground wave radar motion compensation method as claimed in claim 8, wherein Δ R is estimated by a differential evolution algorithm st (t a ) Comprises the following steps:
step 4.1, firstly, analyzing Wigner-Ville distribution of target ship echo signals, and obtaining Doppler center frequency and modulation frequency through Radon transformation;
step 4.2, estimating by adopting a differential evolution algorithm, and constructing the AML with ideal target azimuth focusing peak response according to the Doppler center frequency and the modulation frequency estimated in the step 4.1 ideal ＝sinc(B a t a ) In which B is a ＝k a T ac For Doppler bandwidth, T, of echo signals ac For accumulation time, sinc (·) is a sine function;
the fitness function was chosen to be f = PF (AML-AML) ideal ) 2 Wherein AML is the actual azimuth focusing peak response, PF is the penalty function;
setting the gene dimension of each individual as 6, and respectively corresponding to the amplitude, period and phase of the swaying and surging motion of the target ship; obtaining an individual with the minimum fitness value as an optimal individual by adopting a differential evolution algorithm, and estimating the oscillation motion component delta R of the target ship according to corresponding information in individual genes st (t a )。
10. The shore-vessel bistatic high-frequency ground wave radar motion compensation method according to claim 9,
when the azimuth compression is carried out according to the Doppler parameter estimated from the echo signal, the distance R (t) in the echo signal phase after the motion compensation is carried out a ) Multiplying by the azimuth compression matching function H in the Doppler frequency domain 2 (f a )
Wherein f is a Is the Doppler frequency domain, f ac Is the Doppler center frequency, k a For Doppler frequency modulation, these parameters are estimated by the Wigner-Ville distribution and Radon transform.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210582487.3A CN114966686B (en) | 2022-05-26 | 2022-05-26 | Bank-ship bistatic high-frequency ground wave radar motion compensation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210582487.3A CN114966686B (en) | 2022-05-26 | 2022-05-26 | Bank-ship bistatic high-frequency ground wave radar motion compensation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114966686A CN114966686A (en) | 2022-08-30 |
| CN114966686B true CN114966686B (en) | 2023-03-03 |
Family
ID=82955570
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210582487.3A Active CN114966686B (en) | 2022-05-26 | 2022-05-26 | Bank-ship bistatic high-frequency ground wave radar motion compensation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114966686B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102841337A (en) * | 2012-04-23 | 2012-12-26 | 哈尔滨工业大学 | Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal |
| EP2650695A1 (en) * | 2012-08-02 | 2013-10-16 | Institute of Electronics, Chinese Academy of Sciences | Imaging method for synthetic aperture radar in high squint mode |
| CN106597396A (en) * | 2016-12-21 | 2017-04-26 | 中国海洋大学 | Shipborne HF ground wave radar echo signal simulator |
| CN107942312A (en) * | 2017-11-13 | 2018-04-20 | 浙江大学 | A kind of Intelligent radar sea target detection system and method based on differential evolution invasive weed optimization algorithm |
| CN111537972A (en) * | 2020-05-14 | 2020-08-14 | 中国海洋大学 | Shipborne high-frequency ground wave radar motion parameter identification and motion compensation method |
| CN111856462A (en) * | 2020-07-20 | 2020-10-30 | 西安电子科技大学 | ISAR ship target imaging method based on MPT-MDPT |
| CN114185047A (en) * | 2021-12-09 | 2022-03-15 | 电子科技大学 | Bistatic SAR moving target refocusing method based on optimal polar coordinate transformation |
| CN114236535A (en) * | 2021-12-16 | 2022-03-25 | 中国海洋大学 | Shipborne high-frequency ground wave radar motion compensation method based on double reference radio frequency signals |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110520750B (en) * | 2017-03-03 | 2023-11-14 | Iee国际电子工程股份公司 | Method and system for wireless detection of objects using MIMO radar |
| CN108627833B (en) * | 2018-05-15 | 2021-08-24 | 电子科技大学 | Atmospheric phase compensation method based on GB-InSAR |
-
2022
- 2022-05-26 CN CN202210582487.3A patent/CN114966686B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102841337A (en) * | 2012-04-23 | 2012-12-26 | 哈尔滨工业大学 | Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal |
| EP2650695A1 (en) * | 2012-08-02 | 2013-10-16 | Institute of Electronics, Chinese Academy of Sciences | Imaging method for synthetic aperture radar in high squint mode |
| CN106597396A (en) * | 2016-12-21 | 2017-04-26 | 中国海洋大学 | Shipborne HF ground wave radar echo signal simulator |
| CN107942312A (en) * | 2017-11-13 | 2018-04-20 | 浙江大学 | A kind of Intelligent radar sea target detection system and method based on differential evolution invasive weed optimization algorithm |
| CN111537972A (en) * | 2020-05-14 | 2020-08-14 | 中国海洋大学 | Shipborne high-frequency ground wave radar motion parameter identification and motion compensation method |
| CN111856462A (en) * | 2020-07-20 | 2020-10-30 | 西安电子科技大学 | ISAR ship target imaging method based on MPT-MDPT |
| CN114185047A (en) * | 2021-12-09 | 2022-03-15 | 电子科技大学 | Bistatic SAR moving target refocusing method based on optimal polar coordinate transformation |
| CN114236535A (en) * | 2021-12-16 | 2022-03-25 | 中国海洋大学 | Shipborne high-frequency ground wave radar motion compensation method based on double reference radio frequency signals |
Non-Patent Citations (4)
| Title |
|---|
| Azimuth Resolution Improvement and Target Parameters Inversion for Distributed Shipborne High Frequency Hybrid Sky-Surface Wave Radar;Mingkai Ding 等;《remote sensing》;20210624;第1-27页 * |
| Track prediction for hf radar vessels submerged in strong clutter based on mscnn fusion with gru-am and ar mode;Ling Zhang 等;《remote sensing》;20210531;第1-21页 * |
| 天发船收高频雷达海面目标回波建模;丁明凯 等;《信号处理》;20201231;第36卷(第12期);第2007-2015页 * |
| 稀疏场景目标的距离像峰值聚类分割成像方法;杨秋 等;《测绘学报》;20150830;第44卷(第8期);第900-908页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114966686A (en) | 2022-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106353744B (en) | Multi-parameter combined estimation method based on bistatic FDA-MIMO radars | |
| CN101770022B (en) | Multiple input multiple output (MIMO) radar array position error self-correcting method based on genetic algorithm | |
| CN105974389B (en) | Machine based on iterative processing sweeps metre wave radar Monopulse estimation method | |
| CN109188387B (en) | Target parameter estimation method for distributed coherent radar based on interpolation compensation | |
| CN105974390B (en) | Ji Sao metre wave radars mass centre angle-measuring method based on doppler information | |
| CN110488255A (en) | A kind of phased-array radar pulse high-resolution angle measuring system and method | |
| CN111337917B (en) | FMCW radar high-precision distance estimation method based on variable step interpolation iteration | |
| CN107037418B (en) | A kind of bounded space bearing calibration of the super directive property multipole vector array of low frequency | |
| CN102520399B (en) | Electromagnetic vector array based angle estimation method for metric-wave radar | |
| CN108845325A (en) | Towed linear-array sonar submatrix error misfits estimation method | |
| CN111796279B (en) | Passive electromagnetic vortex SAR (synthetic aperture radar) azimuth super-resolution imaging method and device | |
| CN111896957B (en) | Ship target foresight three-dimensional imaging method based on wavelet transformation and compressed sensing | |
| CN108490443A (en) | Multiple submatrixes synthetic aperture sonar ω k imaging algorithms based on analytic solutions and NUFFT | |
| CN103033812B (en) | Space pursing synchronization method of airborne bistatic synthetic aperture radar (SAR) beam | |
| CN105445718A (en) | DOA estimation method for distributed multi-carrier-warship BVR (beyond visual range) radar based on array reconfiguration | |
| CN107390197A (en) | The radar self-adaption and difference beam angle-measuring method in feature based space | |
| CN107728112A (en) | Robust ada- ptive beamformer method in the case of goal orientation vector severe mismatch | |
| CN113589284B (en) | Imaging method and system for ship target by inverse synthetic aperture radar | |
| CN113156444B (en) | Multi-beam sonar high-precision imaging method based on motion compensation | |
| CN114966686B (en) | Bank-ship bistatic high-frequency ground wave radar motion compensation method | |
| CN100585429C (en) | Passive channel correcting method based on non-linear antenna array | |
| CN111736129B (en) | Space-time modulation bistatic radar system, implementation method and medium thereof | |
| CN111537972B (en) | Shipborne high-frequency ground wave radar motion parameter identification and motion compensation method | |
| CN106125039A (en) | Improvement space-time adaptive Monopulse estimation method based on local Combined Treatment | |
| CN109884621B (en) | Radar altimeter echo coherent accumulation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |