CN105738887A - Airborne radar clutter power spectrum optimization method based on Doppler channel division - Google Patents

Abstract

The invention discloses an airborne phased array radar clutter power spectrum optimization method. The idea of the method is that an airborne phased array radar geometric model is established, and ground clutter normalization Doppler frequency received by airborne phased array radar is acquired, based on which transmitting signal voltage gain of the airborne phased array radar and receiving signal voltage gain of the airborne phased array radar are obtained so that double signal voltage gain and double signal power gain of the airborne phased array radar are obtained; then a clutter ring grazing angle and clutter block area on a clutter block are obtained according to clutter ring slant distance so that clutter power of the airborne phased array radar is obtained, based on which clutter power of the airborne phased array radar and a clutter covariance matrix are obtained; and finally azimuth steering vectors and pitch steering vectors of the airborne phased array radar are obtained and then space-domain steering vectors and space-time steering vectors of the airborne phased array radar, a clutter and noise covariance matrix of the airborne phased array radar and a clutter power spectrum of the airborne phased array radar are obtained in turn.

Description

Optimization method based on the airborne radar clutter power spectrum that Doppler's passage divides

Technical field

The invention belongs to Radar Technology field, particularly to the optimization method of a kind of airborne radar clutter power spectrum divided based on Doppler's passage, it is adaptable to airborne phased array radar carries out the emulation of land clutter power spectrum.

Background technology

Radar is indispensable equipment in modern war, is a kind of by electromagnetic wave with receive the equipment that target is detected and measures target information by echo.But when target is present in natural environment, electromagnetic wave or reception echo also can be produced scattering by natural environment, thus target detection is produced interference, these interference are referred to as radar clutter.For looking the airborne phased array radar of working method under adopting, land clutter is very prominent on the impact of target detection, and therefore the rejection ability of land clutter has just become the important indicator of the airborne Phased Array Radars of inspection.

In order to obtain clutter suppression method effectively, promote airborne phased array radar in land clutter, detect the ability of weak target, it is necessary to the ground mixed wave specific of airborne phased array radar working environment is had fully complete understanding.But the land clutter data of actual measurement can not obtain at short notice, and spend high.Raising along with computer technology, related researcher is made to utilize computer technology to obtain the method suppressing land clutter, study the ground mixed wave specific of airborne phased array radar with this, and then the system for airborne phased array radar designs and signal processing provides emulation data, just seems particularly important.

Wherein, J.Ward proposes traditional emulation mode suppressing land clutter, this emulation mode is, in rectangular coordinate system, by equidistant ring and azimuth, land clutter is divided into several clutter unit, then the clutter echo on wherein any one rang ring is modeled as the land clutter of N number of independent clutter block, N is the natural number more than 1, N number of independent clutter block is to obtain so that respective distances ring is carried out being evenly dividing by set angle interval in azimuth, then the N number of independent clutter block after being evenly dividing is calculated power spectrum and Doppler frequency respectively, corresponding Doppler's passage is obtained further according to the Doppler frequency calculated.Assume that emulation has M Doppler's passage, M is the natural number more than 1, clutter on one rang ring is divided into N number of independent clutter block, generally the precision for guaranteeing emulation land clutter data is sufficiently high and make N much larger than M, but reality but only has M Doppler's passage, make the clutter block number divided due to rang ring more and cause the overlong time of operably Clutter simulation program, thus the emulation data of land clutter cannot be drawn in time, and then cause that the design of the system to airborne phased array radar afterwards and signal processing bring huge inconvenience.

Summary of the invention

For the deficiency that prior art exists, it is an object of the invention to propose the optimization method of a kind of airborne radar clutter power spectrum divided based on Doppler's passage, the optimization method of the airborne radar clutter power spectrum that this kind divides based on Doppler's passage suppresses on the basis of land clutter method in the J.Ward tradition proposed, employing pitches up and is divided by equidistant ring by land clutter, Doppler azimuth upwards improves the original method being evenly dividing, clutter on any one rang ring is first calculated the Doppler frequency range of clutter on this rang ring, corresponding Doppler's channel range is obtained according to Doppler frequency range, the Doppler frequency making clutter on this rang ring covers Doppler's passage, then the clutter on this rang ring is divided according to Doppler's port number, thus substantially reducing the time running Clutter simulation program.

For reaching above-mentioned technical purpose, the present invention adopts the following technical scheme that and is achieved.

The optimization method of a kind of airborne radar clutter power spectrum divided based on Doppler's passage, comprises the following steps:

Step 1, sets up airborne phased array radar geometric model, and in described airborne phased array radar geometric model, the antenna main beam azimuth of airborne phased array radar is θ₀, the antenna main beam angle of pitch of airborne phased array radar isDoppler's channel number of airborne phased array radar is N_c, and airborne phased array radar receives the land clutter in detection range, and is evenly dividing as L clutter ring by described land clutter according to setting width Delta l, and the oblique distance that the l clutter ring is corresponding is R_l, more each clutter ring is divided into N based on Doppler's passage_cIndividual clutter block, the angle of pitch of the l clutter ringIt is expressed as:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos () operates for anticosine, R_lIt is the oblique distance that the l clutter ring is corresponding, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar；

Then, described N is chosen_cThe center hold angle of the kth clutter block in individual clutter block, as the azimuth angle theta of kth clutter block_k, and the angle of pitch according to the l clutter ringCalculate and obtain the land clutter normalization Doppler frequency f that airborne phased array radar receives_d；

Step 2, the angle of pitch according to the l clutter ringThe land clutter normalization Doppler frequency f received with airborne phased array radar_d, respectively calculate obtain airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on transmitting gain voltage signalWith airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on reception voltage signal gainAnd accordingly calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip gain voltage signalAnd then calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainWherein, round trip represents to be launched and receives, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, θ_kFor the azimuth of kth clutter block,It it is the angle of pitch of the l clutter ring；

Step 3, is R according to the oblique distance that the l clutter ring is corresponding_l, calculate the grazing angle ψ obtaining on the l clutter ring_l, and calculate the kth block clutter block area S obtaining on the l clutter ring accordingly_lk, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter power

Step 4, the azimuth angle theta according to kth clutter block_kThe angle of pitch with the l clutter ringCalculate respectively obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter orientation to steering vectorWith airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter pitching to steering vectorCalculate the clutter spatial domain steering vector s of the kth block clutter block obtained on the l clutter ring accordingly_lk, and then calculate steering vector s during the clutter sky of the kth block clutter block obtained on the l clutter ring_st, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter powerCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrix

Step 5, the antenna main beam azimuth angle theta according to airborne phased array radar₀The antenna main beam angle of pitch with airborne phased array radarCalculate the orientation of airborne phased array radar respectively to steering vector s_a0Pitching with airborne phased array radar is to steering vector s_e0, and calculate the spatial domain steering vector s obtaining airborne phased array radar accordingly successively_s0Steering vector s during with airborne phased array radar empty₀, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrixCalculate and obtain the clutter plus noise covariance matrix R of airborne phased array radar, and steering vector s during according to airborne phased array radar empty₀, calculate the clutter power spectrum P obtaining airborne phased array radar_c。

Beneficial effects of the present invention: the optimization method of a kind of airborne radar clutter power spectrum based on the division of Doppler's passage of the present invention is on the basis of the Clutter simulation method of J.Ward, first Doppler's port number that land clutter covers upwards first is calculated in orientation, then clutter block is divided according to Doppler's passage, the clutter block Doppler frequency on a clutter ring is made only to cover little Doppler's passage, thus decreasing the block number that clutter divides, obtaining, the basis of Clutter simulation data true to nature shortens the time needed for Clutter simulation.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention will be further described.

Fig. 1 is the optimization method flow chart of a kind of airborne radar clutter power spectrum divided based on Doppler's passage of the present invention；Wherein, in three-dimensional system of coordinate XOYZ, X, Y, Z be coordinate axes respectively, Z and X, Y constitute right-handed coordinate system, carrier aircraft and airborne phased array radar are integrated, and airborne phased array radar is placed in carrier aircraft, using carrier aircraft subpoint on the ground as zero O, and with speed v along Y direction forward horizontal flight, R_lIt is the oblique distance that the l clutter ring is corresponding,It is the angle of pitch of the l clutter ring, θ_kAzimuth for kth clutter block；

Fig. 2 is the coordinate system schematic diagram of carrier aircraft and airborne phased array radar；

Fig. 3 is the clutter distance-Doppler figure using the Clutter simulation method of J.Ward to obtain；Wherein, abscissa represents Doppler, and vertical coordinate represents distance；

Fig. 4 is the clutter distance-Doppler figure using the inventive method to obtain；Wherein, abscissa represents Doppler, and vertical coordinate represents distance.

Detailed description of the invention

With reference to Fig. 1, for the optimization method flow chart of a kind of airborne radar clutter power spectrum divided based on Doppler's passage of the present invention, the optimization method of the airborne radar clutter power spectrum that this kind divides based on Doppler's passage, comprise the following steps:

Step 1, sets up airborne phased array radar geometric model, and in described airborne phased array radar geometric model, the antenna main beam azimuth of airborne phased array radar is θ₀, the antenna main beam angle of pitch of airborne phased array radar isDoppler's channel number of airborne phased array radar is N_d, and airborne phased array radar receives the land clutter in detection range, and is evenly dividing as L clutter ring by described land clutter according to setting width Delta l, and the oblique distance that the l clutter ring is corresponding is R_l, more each clutter ring is divided into N based on Doppler's passage_cIndividual clutter block, the angle of pitch of the l clutter ringIt is expressed as:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos () operates for anticosine, R_lIt is the oblique distance that the l clutter ring is corresponding, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar.

Then, described N is chosen_cThe center hold angle of the kth clutter block in individual clutter block, as the azimuth angle theta of kth clutter block_k, and the angle of pitch according to the l clutter ringCalculate and obtain the land clutter normalization Doppler frequency f that airborne phased array radar receives_d。

Specifically, with reference to Fig. 2, for the coordinate system schematic diagram of carrier aircraft Yu airborne phased array radar；In three-dimensional system of coordinate XOYZ, X, Y, Z be coordinate axes respectively, and Z and X, Y constitute right-handed coordinate system, and carrier aircraft and airborne phased array radar are integrated, airborne phased array radar is placed in carrier aircraft, using carrier aircraft subpoint on the ground as zero O, the carrier aircraft height of airborne phased array radar is H, and with speed v along Y direction forward horizontal flight, airborne phased array radar in carrier aircraft is positive side-looking mounting means, the antenna array of airborne phased array radar is rectangle plane, and wherein, level is to comprising N_aIndividual array element, pitching is to comprising N_eIndividual array element, level to and pitching to array element interval respectively d；The antenna main beam orientation of airborne phased array radar is vertical to the normal of the rectangle front with Phased Array Radar Antenna, the antenna main beam pitching of airborne phased array radar to point to horizontal line of sight infinite point；The pulse recurrence frequency of airborne phased array radar is f_r, the transmitting gain of airborne phased array radar with receive gain respectively G_t、G_r, the receiver bandwidth of airborne phased array radar is B, and the transmitting umber of pulse of airborne phased array radar is M, and the FFT of airborne phased array radar counts as N_d；Owing to Doppler's port number of airborne phased array radar is equal to the described FFT number counted, so airborne phased array radar Doppler's channel number is N_d；The carrier wavelength of airborne phased array radar is λ,f₀For the transmitting signal carrier frequency of airborne phased array radar, c is light spread speed in a vacuum；The antenna array level of airborne phased array radar is spaced apart d to array element_y, the antenna array pitching of airborne phased array radar is spaced apart d to array element_z, and carrier wavelength with half airborne phased array radar is spaced apart respectively, namely

In this kind of airborne phased array radar geometric model, airborne phased array radar receives the land clutter in detection range, and the land clutter distribution distance that described airborne phased array radar front receives ranges for H to R_max, wherein H is carrier aircraft height,For the maximum horizon grange of airborne phased array radar, R_eFor earth radius；And described land clutter is evenly dividing as L clutter ring according to setting width Delta l, the oblique distance that the l clutter ring is corresponding is R_l, and R_l=l Δ l, H≤R_l≤R_max,For the width of any one clutter ring, more each clutter ring is divided into N_cIndividual clutter block, the angle of pitch of the l clutter ringIt is expressed as:

Then, described N is chosen_cThe center hold angle of the kth clutter block in individual clutter block, as the azimuth angle theta of kth clutter block_k, and the angle of pitch according to the l clutter ringCalculate and obtain the land clutter normalization Doppler frequency f that airborne phased array radar receives_d, and then calculating obtains the maximum normalization Doppler frequency f of land clutter that airborne phased array radar receives successively_dmaxThe minimally clutter normalization Doppler frequency f received with airborne phased array radar_dmin, its expression formula is:

Owing to carrier aircraft and airborne phased array radar are integrated, airborne phased array radar is placed in carrier aircraft, so axial and carrier aircraft speed the angle of airborne phased array radar front is 0, i.e. and α=0 °；The azimuth angle theta of kth clutter block_kSpan is 0 °-180 °；Azimuth angle theta when kth clutter block_kWhen=0 °, calculate and obtain the maximum normalization Doppler frequency f of land clutter that airborne phased array radar front receives_dmax；Work as θ_kWhen=180 °, calculate and obtain the minimum normalization Doppler frequency f of land clutter that airborne phased array radar front receives_dmin, its expression formula is respectively as follows:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos () operates for anticosine, R_lIt is oblique distance corresponding to the l range gate, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar, and v is the carrier aircraft speed of airborne phased array radar, f_rFor the pulse recurrence frequency of airborne phased array radar,f₀For the transmitting signal carrier frequency of airborne phased array radar, c is light spread speed in a vacuum, θ_kFor the azimuth that kth clutter block is corresponding,Be the clutter block angle of pitch that the l clutter ring is corresponding, α be airborne phased array radar front axially and the angle of carrier aircraft speed.

According to the maximum normalization Doppler frequency f of land clutter that airborne phased array radar receives_dmaxThe minimally clutter normalization Doppler frequency f received with airborne phased array radar_dmin, obtain described minimum normalization Doppler frequency f accordingly respectively_dminWith described maximum normalization Doppler frequency f_dmaxEach self-corresponding Doppler passage N₁With N₂, thus knowing the azimuth angle theta of kth clutter block_kDoppler's port number that land clutter in set point covers is N_c, i.e. the azimuth angle theta of kth clutter block_kDoppler's port number that land clutter within the scope of 0 °-180 ° covers is N_c；Owing to airborne phased array radar Doppler's channel number is N_d, so the width of each Doppler's passage isTherefore the azimuth angle theta of kth clutter block_kThe Doppler port number N that land clutter within the scope of 0 °-180 ° covers_cIt is from N₁Individual Doppler's passage starts, withFor interval, until N₂Individual Doppler's channel end, i.e. N_c=N₂-N₁+1。

Step 2, the angle of pitch according to the l clutter ringThe land clutter normalization Doppler frequency f received with airborne phased array radar_d, respectively calculate obtain airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on transmitting gain voltage signalWith airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on reception voltage signal gainAnd accordingly calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip gain voltage signalAnd then calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainWherein, round trip represents to be launched and receives, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, θ_kFor the azimuth of kth clutter block,It it is the angle of pitch of the l clutter ring.

Specifically, the land clutter normalization Doppler frequency f received according to airborne phased array radar_d, know the land clutter normalization Doppler frequency f that airborne phased array radar receives_dThe left margin f of place Doppler's passage_dlWith right margin f_dr, and Extrapolation obtains the azimuth left margin θ of kth clutter block accordingly_klAzimuth right margin θ with kth clutter block_kr, its expression formula is:

Azimuth left margin θ according to kth clutter block_klAzimuth right margin θ with kth clutter block_kr, calculate the center hold angle obtaining kth clutter block, the i.e. azimuth angle theta of kth clutter block_k, its expression formula is:

${\mathrm{\θ}}_k=\frac{{\mathrm{\θ}}_{kl}+{\mathrm{\θ}}_{kr}}{2}$

Owing to the antenna main beam orientation of airborne phased array radar is vertical to the normal of the rectangle front with Phased Array Radar Antenna, the antenna main beam pitching of airborne phased array radar to point to horizontal line of sight infinite point；Therefore the antenna main beam azimuth angle theta of airborne phased array radar₀The antenna main beam angle of pitch with airborne phased array radarRespectively 90 ° and 0 °, then utilize the azimuth angle theta of kth clutter block_kThe angle of pitch with the l clutter ringRespectively calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on transmitting gain voltage signalWith airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on reception voltage signal gainAnd accordingly calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip gain voltage signalAnd then calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainIts expression formula is respectively as follows:

Wherein, round trip represents to be launched and receives, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, θ_kFor the azimuth of kth clutter block,It is the angle of pitch of the l clutter ring, | | | |_∞Representing Infinite Norm, ⊙ represents dot product, f_dFor the land clutter normalization Doppler frequency that airborne phased array radar receives, na ∈ 1,2 ..., N_a, ne ∈ 1,2 ..., N_e, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, d is array element interval, andd_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval；θ₀For the azimuth of the antenna main beam of airborne phased array radar,For the angle of pitch of the antenna main beam of airborne phased array radar, w_naFor orientation, Airborne Phased Array Radar Antenna Array face to n-th a array element windowing weights, w_neFor the pitching of Airborne Phased Array Radar Antenna Array face to n-th e array element windowing weights.

Step 3, is R according to the oblique distance that the l clutter ring is corresponding_l, calculate the grazing angle ψ obtaining on the l clutter ring_l, and calculate the kth block clutter block area S obtaining on the l clutter ring accordingly_lk, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter power

Specifically, the grazing angle ψ on the l clutter ring_lExpression formula is:

Azimuth left margin θ due to kth clutter block_klAzimuth right margin θ with kth clutter block_kr, the azimuth coverage that therefore kth block clutter block is corresponding is: Δ θ_k=θ_kr-θ_kl。

Then the kth block clutter block area S obtaining on the l clutter ring is calculated accordingly_lk, its expression formula is:

$S_{lk}=R_l\·{\mathrm{\Δ\θ}}_k\·\frac{c}{2B}$

Further according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter powerIts expression formula is:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, R_lIt is the oblique distance that the l clutter ring is corresponding, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar, and c is light spread speed in a vacuum, and B is the receiver bandwidth of airborne phased array radar, G_tAnd G_rThe respectively transmitting gain of airborne phased array radar and reception gain, σ₀For the clutter backscattering coefficient of airborne phased array radar, and σ₀=γ sin ψ_l, ψ_lBeing the grazing angle on the l clutter ring, γ is clutter normalization backscattering coefficient, and its value is relevant with actual landform；λ is the carrier wavelength of airborne phased array radar, P_tFor the emission peak power of airborne phased array radar, L_sFor the loss of airborne phased array radar, τ is the fire pulse width of airborne phased array radar.

Step 4, the azimuth angle theta according to kth clutter block_kThe angle of pitch with the l clutter ringCalculate respectively obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter orientation to steering vectorWith airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter pitching to steering vectorCalculate the clutter spatial domain steering vector s of the kth block clutter block obtained on the l clutter ring accordingly_lk, and then calculate steering vector s during the clutter sky of the kth block clutter block obtained on the l clutter ring_st, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter powerCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrix

Specifically, airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter orientation to steering vectorIts expression formula is:

Airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter pitching to steering vectorIts expression formula is:

The clutter spatial domain steering vector s of the kth block clutter block on the l clutter ring_lk, its expression formula is:

Steering vector s during the clutter sky of the kth block clutter block on the l clutter ring_st, its expression formula is:

$s_{st}=s_{lk}\⊗s_t$

Airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrixIts expression formula is:

Wherein, s_tFor airborne phased array radar receive land clutter time domain steering vector, and $s_t={\[w_0,w_1{e}^{j2{\mathrm{\πf}}_d},...,w_n{e}^{j2{\mathrm{\πf}}_{d}n},...,w_{M-1}{e}^{j2{\mathrm{\πf}}_d(M-1)}\]}^T,$ Represent that Kronecker amasss；L ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos () operates for anticosine, R_lBeing the oblique distance that the l clutter ring is corresponding, λ is the carrier wavelength of airborne phased array radar, na ∈ 1,2 ..., N_a, ne ∈ 1,2 ..., N_e, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, d is array element interval, andd_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval.

Step 5, the antenna main beam azimuth angle theta according to airborne phased array radar₀The antenna main beam angle of pitch with airborne phased array radarCalculate the orientation of airborne phased array radar respectively to steering vector s_a0Pitching with airborne phased array radar is to steering vector s_e0, and calculate the spatial domain steering vector s obtaining airborne phased array radar accordingly successively_s0Steering vector s during with airborne phased array radar empty₀, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrixCalculate and obtain the clutter plus noise covariance matrix R of airborne phased array radar, and steering vector s during according to airborne phased array radar empty₀, calculate the clutter power spectrum P obtaining airborne phased array radar_c。

Specifically, the orientation of airborne phased array radar is to steering vector s_a0Pitching with airborne phased array radar is to steering vector s_e0Expression formula be respectively as follows:

The spatial domain steering vector s of airborne phased array radar_s0Steering vector s during with airborne phased array radar empty₀Expression formula be respectively as follows: $s_{s0}=s_{a0}\⊗s_{e0},s_0=w_0\⊗s_{s0}.$

The expression formula of the clutter plus noise covariance matrix R of airborne phased array radar is:

The clutter power spectrum P of airborne phased array radar_cExpression formula be:

Wherein, d_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval, λ is the carrier wavelength of airborne phased array radar, θ₀For the azimuth of the antenna main beam of airborne phased array radar,For the angle of pitch of the antenna main beam of airborne phased array radar, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_a>=1, N_e>=1, subscript T represents transposition,Represent that Kronecker amasss, w₀For first weights of time-domain windowed, R_nFor noise covariance matrix, andFor noise power；R_cFor the clutter covariance matrix of airborne phased array radar, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that in the detection range that airborne phased array radar receives, land clutter comprises, N_cFor the clutter block number that each clutter ring comprises, subscript H represents conjugate transpose, ()^-1Represent inversion operation.

Below in conjunction with emulation experiment, effect of the present invention is described in further details.

(1) simulation parameter

In the emulation experiment of the present invention, the carrier aircraft height H=8000m of airborne phased array radar, the carrier aircraft speed v=200m/s of airborne phased array radar, the transmitting signal carrier frequency f of airborne phased array radar₀For 1.5GHz, the phased-array radar in carrier aircraft is positive side-looking mounting means, therefore airborne phased array radar front and carrier aircraft velocity angle α=0 °, the antenna main beam azimuth angle theta of airborne phased array radar₀=90 °, the antenna main beam angle of pitch of airborne phased array radarThe level in Airborne Phased Array Radar Antenna Array face is to the element number of array N comprised_a=128, the pitching in Airborne Phased Array Radar Antenna Array face is to the element number of array N comprised_e=10, array element interval d is 0.1m, the pulse recurrence frequency f of airborne phased array radar_r=6000Hz, the receiver bandwidth B=5MHz of airborne phased array radar, the transmitting umber of pulse M=64 of airborne phased array radar, the FFT points N of airborne phased array radar_d=128, the emission peak power of airborne phased array radar is 600kW, the loss L of airborne phased array radar_s=7dB, clutter normalization backscattering coefficient γ=-13dB.

(2) emulation data processed result and analysis

A. in order to the superiority of the present invention is described, first the Clutter simulation method of J.Ward is used to carry out Clutter simulation according to above-mentioned radar system parameters, each clutter ring is equally divided into 6000 clutter blocks, then the inventive method emulation is adopted, the method adopts Doppler's division that the clutter of each clutter ring carries out clutter block division, and the clutter block after dividing is carried out data process.

Under same parameter, use J.Ward Clutter simulation method carry out Clutter simulation program has run consuming time be: 27884 seconds；And use the inventive method emulation clutter program has run consuming time be: 593 seconds.Therefore compared to using the Clutter simulation method of J.Ward, the inventive method has absolute advantage on simulation velocity.

B. in order to further illustrate the advantage of the present invention, Fig. 3 is the clutter distance-Doppler figure using the Clutter simulation method of J.Ward to obtain；Wherein, abscissa represents Doppler, and vertical coordinate represents distance；Fig. 4 is the clutter distance-Doppler figure using the inventive method to obtain；Wherein, abscissa represents Doppler, and vertical coordinate represents distance.

From figure 3, it can be seen that carry out emulating in the clutter range Doppler figure obtained in the Clutter simulation method using J.Ward, the rectangular strip on the right represents decibels (dB), and color more bright place noise level is more high.From fig. 4, it can be seen that in the clutter data range Doppler figure using the inventive method to obtain, the rectangular strip on the right represents decibels (dB), and color more bright place noise level is more high.Comparison diagram 3 can be seen that with Fig. 4 the clutter range Doppler figure using the Clutter simulation method of J.Ward to obtain is almost identical with the clutter range Doppler figure using the inventive method to obtain, airborne phased array radar front and carrier aircraft velocity angle α=0 °, therefore land clutter integrated distribution is near zero Doppler frequency, therefore the land clutter data that the inventive method emulation obtains are correct, therefore use the inventive method can embody noise performance true to nature.

By above-mentioned analysis it can be concluded that the Clutter simulation method of the present invention Clutter simulation method compared with J.Ward has great advantage, it is possible to use this method obtains Clutter simulation data true to nature more quickly.

In sum, emulation experiment demonstrates the correctness of the present invention, validity and reliability.

Obviously, the present invention can be carried out various change and modification without deviating from the spirit and scope of the present invention by those skilled in the art；So, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.

Claims (7)

1. the optimization method of the airborne radar clutter power spectrum divided based on Doppler's passage, it is characterised in that comprise the following steps:

Step 1, sets up airborne phased array radar geometric model, and in described airborne phased array radar geometric model, the antenna main beam azimuth of airborne phased array radar is θ₀, the antenna main beam angle of pitch of airborne phased array radar isDoppler's channel number of airborne phased array radar is N_d, and airborne phased array radar receives the land clutter in detection range, and is evenly dividing as L clutter ring by described land clutter according to setting width △ l, and the oblique distance that the l clutter ring is corresponding is R_l, more each clutter ring is divided into N based on Doppler's passage_cIndividual clutter block, the angle of pitch of the l clutter ringIt is expressed as:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos (i) operates for anticosine, R_lIt is the oblique distance that the l clutter ring is corresponding, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar；

Then, described N is chosen_cThe center hold angle of the kth clutter block in individual clutter block, as the azimuth angle theta of kth clutter block_k, and the angle of pitch according to the l clutter ringCalculate and obtain the land clutter normalization Doppler frequency f that airborne phased array radar receives_d；

Step 2, the angle of pitch according to the l clutter ringThe land clutter normalization Doppler frequency f received with airborne phased array radar_d, respectively calculate obtain airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on transmitting gain voltage signalWith airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on reception voltage signal gainAnd accordingly calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip gain voltage signalAnd then calculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gain

Wherein, round trip represents to be launched and receives, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, θ_kFor the azimuth of kth clutter block,It it is the angle of pitch of the l clutter ring；

Step 3, is R according to the oblique distance that the l clutter ring is corresponding_l, calculate the grazing angle ψ obtaining on the l clutter ring_l, and calculate the kth block clutter block area S obtaining on the l clutter ring accordingly_lk, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter power

Step 4, the azimuth angle theta according to kth clutter block_kThe angle of pitch with the l clutter ringCalculate respectively obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter orientation to steering vectorWith airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter pitching to steering vectorCalculate the clutter spatial domain steering vector s of the kth block clutter block obtained on the l clutter ring accordingly_lk, and then calculate steering vector s during the clutter sky of the kth block clutter block obtained on the l clutter ring_st, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter powerCalculate obtain airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrix

Step 5, the antenna main beam azimuth angle theta according to airborne phased array radar₀The antenna main beam angle of pitch with airborne phased array radarCalculate the orientation of airborne phased array radar respectively to steering vector s_a0Pitching with airborne phased array radar is to steering vector s_e0, and calculate the spatial domain steering vector s obtaining airborne phased array radar accordingly successively_s0Steering vector s during with airborne phased array radar empty₀, then according to airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrixCalculate and obtain the clutter plus noise covariance matrix R of airborne phased array radar, and steering vector s during according to airborne phased array radar empty₀, calculate the clutter power spectrum P obtaining airborne phased array radar_c。

2. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterised in that in step 1, the land clutter normalization Doppler frequency f that described airborne phased array radar receives_d, its expression formula is:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, v is the carrier aircraft speed of airborne phased array radar, f_rFor the pulse recurrence frequency of airborne phased array radar,f₀For the transmitting signal carrier frequency of airborne phased array radar, c is light spread speed in a vacuum, θ_kFor the azimuth that kth clutter block is corresponding,Be the clutter block angle of pitch that the l clutter ring is corresponding, α be airborne phased array radar front axially and the angle of carrier aircraft speed.

3. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterised in that in step 1, described is divided into N by each clutter ring based on Doppler's passage_cIndividual clutter block, wherein, N_cIt is from N₁Individual Doppler's passage starts, withFor interval, until N₂Individual Doppler's channel end, i.e. N_c=N₂-N₁+ 1, N₂For the maximum normalization Doppler frequency f of land clutter that airborne phased array radar receives_dmaxCorresponding Doppler's passage, N₁For the minimally clutter normalization Doppler frequency f that airborne phased array radar receives_dminCorresponding Doppler's passage.

4. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterized in that, in step 2, described airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on transmitting gain voltage signalWith described airborne phased array radar the clutter block angle of pitch of the l clutter ring, kth clutter block azimuth on reception voltage signal gainIts expression formula is respectively as follows:

Described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip gain voltage signalWith described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on round trip signal power gainIts expression formula is respectively as follows:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, θ_kFor the azimuth of kth clutter block,It is the angle of pitch of the l clutter ring, | | | |_∞Representing Infinite Norm, ⊙ represents dot product, f_dFor the land clutter normalization Doppler frequency that airborne phased array radar receives, na ∈ 1,2 ..., N_a, ne ∈ 1,2 ..., N_e, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, d is array element interval, andd_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval；θ₀For the azimuth of the antenna main beam of airborne phased array radar,For the angle of pitch of the antenna main beam of airborne phased array radar, w_naFor orientation, Airborne Phased Array Radar Antenna Array face to n-th a array element windowing weights, w_neFor the pitching of Airborne Phased Array Radar Antenna Array face to n-th e array element windowing weights.

5. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterised in that in step 3, the grazing angle ψ on described the l clutter ring_lWith the kth block clutter block area S on described the l clutter ring_lkExpression formula be respectively as follows:

${\mathrm{\ψ}}_l=asin(\frac{H}{R_l}-\frac{R_l}{2R_e}),S_{lk}=R_l\·{\mathrm{\Δ\θ}}_k\·\frac{c}{2B}$

Described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter powerExpression formula be:

Wherein, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, R_lIt is the oblique distance that the l clutter ring is corresponding, R_eFor earth radius, H is the carrier aircraft height of airborne phased array radar, and c is light spread speed in a vacuum, and B is the receiver bandwidth of airborne phased array radar, G_tAnd G_rThe respectively transmitting gain of airborne phased array radar and reception gain, σ₀For the clutter backscattering coefficient of airborne phased array radar, and σ₀=γ sin ψ_l, ψ_lBeing the grazing angle on the l clutter ring, γ is clutter normalization backscattering coefficient, and its value is relevant with actual landform；λ is the carrier wavelength of airborne phased array radar, P_tFor the emission peak power of airborne phased array radar, L_sFor the loss of airborne phased array radar, τ is the fire pulse width of airborne phased array radar.

6. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterized in that, in step 4, described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter orientation to steering vectorWith described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter pitching to steering vectorIts expression formula is respectively as follows:

The clutter spatial domain steering vector s of the kth block clutter block on described the l clutter ring_lkSteering vector s during with the clutter sky of the kth block clutter block on described the l clutter ring_st, and described airborne phased array radar the angle of pitch of the l clutter ring, kth clutter block azimuth on clutter covariance matrixIts expression formula is respectively as follows:

Wherein, s_tFor airborne phased array radar receive land clutter time domain steering vector, and $s_t={\[w_0,w_1{e}^{j2{\mathrm{\πf}}_d},\mathrm{...},w_n{e}^{j2{\mathrm{\πf}}_{d}n},\mathrm{...},w_{M-1}{e}^{j2{\mathrm{\πf}}_d(M-1)}\]}^T,$ Represent that Kronecker amasss；L ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that the land clutter in the detection range that airborne phased array radar receives comprises, N_cFor the clutter block number that each clutter ring comprises, acos (i) operates for anticosine, R_lBeing the oblique distance that the l clutter ring is corresponding, λ is the carrier wavelength of airborne phased array radar, na ∈ 1,2 ..., N_a, ne ∈ 1,2 ..., N_e, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, d is array element interval, andd_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval.

7. a kind of optimization method of airborne radar clutter power spectrum divided based on Doppler's passage as claimed in claim 1, it is characterised in that in steps of 5, the orientation of described airborne phased array radar is to steering vector s_a0Pitching with described airborne phased array radar is to steering vector s_e0Expression formula be respectively as follows:

The spatial domain steering vector s of described airborne phased array radar_s0Steering vector s during with described airborne phased array radar empty₀Expression formula be respectively as follows: $s_{s0}=s_{a0}\⊗s_{e0},s_0=w_0\⊗s_{s0};$

The clutter plus noise covariance matrix R of described airborne phased array radar and the clutter power spectrum P of described airborne phased array radar_cExpression formula be respectively as follows:

Wherein, d_yFor the antenna array level of airborne phased array radar to array element interval, d_zFor the antenna array pitching of airborne phased array radar to array element interval, λ is the carrier wavelength of airborne phased array radar, θ₀For the azimuth of the antenna main beam of airborne phased array radar,For the angle of pitch of the antenna main beam of airborne phased array radar, N_aFor the level in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_eFor the pitching in Airborne Phased Array Radar Antenna Array face to the element number of array comprised, N_a>=1, N_e>=1, subscript T represents transposition,Represent that Kronecker amasss, w₀For first weights of time-domain windowed, R_nFor noise covariance matrix or noise power, andR_cFor the clutter covariance matrix of airborne phased array radar, l ∈ 1,2 ..., L}, k ∈ 1,2 ..., N_c, L is the clutter ring number that in the detection range that airborne phased array radar receives, land clutter comprises, N_cFor the clutter block number that each clutter ring comprises, subscript H represents conjugate transpose, ()^-1Represent inversion operation.