CN104049241B - The spacing synchronization process of the double-base synthetic aperture radar that target location coordinate is unknown - Google Patents

Abstract

This invention belongs to BiSAR and launches the double-base synthetic aperture radar spacing synchronization process unknown with the target location coordinate in reception technique field.Process and for transmitter including initialization: determine the conversion that unit direction vector carrier coordinate system that antenna points to is vectorial with geographic coordinate system, determine the transmitter vector to center, target area, geographic coordinate system and the conversion of terrestrial coordinate system, determine transmitter vector under terrestrial coordinate system, determine that the position vector at center, target area is for receiver: determine in terrestrial coordinate system position vector, receiver determines that receiver sensing center, target area is pointed to the vectorial sensing vector determined under carrier coordinate system of the vectorial sensing determined under geographic coordinate system and completed receiver and the spatial synchronization of transmitter antenna sensing.The features such as this invention has the efficiency that can be effectively increased double-base SAR spatial synchronization, and degree of accuracy is higher, and offline mode is flexible, the most extensive application.

Description

The spacing synchronization process of the double-base synthetic aperture radar that target location coordinate is unknown

Technical field

The invention belongs to double-base synthetic aperture radar (Bistatic Synthetic Aperture Radar, BiSAR) launch and receive Technical field；A kind of spacing synchronization process of double-base synthetic aperture radar when not knowing target coordinate position accurately.

Background technology

Synthetic aperture radar (Synthetic Aperture Radar, SAR) has round-the-clock, round-the-clock to topography and geomorphology or ground Target carries out high-resolution imaging and pinpoint excellent properties.But, owing to flat pad and the reception of single base SAR are flat Platform shares identical carrier, and its disguise is poor, is easily subject to enemy and scouts and implement interference.Double-base synthetic aperture radar (Bistatic Synthetic Aperture Radar, BiSAR) flat pad and receiving platform be placed on different carriers, it is compared to list Base SAR, it is possible to obtain more rich target information and farther operating distance.Simultaneously as receiving platform is in passive connecing Receipts state, so its interference free performance and security performance also have the biggest lifting.Many excellent properties that BiSAR is had so that It has become the study hotspot that various countries contend mutually in recent years.

BiSAR is owing to have employed the strategy that sending and receiving split, so corresponding simultaneous techniques must be coordinated just to make the property of its excellence Can be played.It is to say, simultaneous techniques is the premise that BiSAR carries out back end signal process.The simultaneous techniques master of BiSAR Including 3 aspects: spatial synchronization, time synchronized and frequency/phase synchronize.This 3 synchronization greatly must be simultaneously achieved, and lacks one not Can, its any one disappearance all can cause serious consequence, even makes BiSAR systemic breakdown.

BiSAR spatial synchronization technology refers to, in the system that sending and receiving split, in real time and efficiently control flat pad and reception The antenna of platform points to, and makes launching beam and reception wave beam be simultaneously irradiated to same object space, to guarantee that receiving platform can have Imitate receives target echo, i.e. target area echo has sufficiently high signal to noise ratio.Publication No. be CN102967851A, The patent document of entitled " spacing synchronization process of a kind of double-base SAR " discloses a kind of coordinate bit based on known target Spacing synchronization process when putting, the method utilizes GPS spatial coordinated information and the attitude information of carrier aircraft (body) platform, by WGS-84 The order of coordinate system, rectangular coordinate system in space, geographic coordinate system, carrier coordinate system and radar reference frame carries out coordinate transform, Obtain the Antenna pointing control parameter of carrier aircraft, finally antenna is pointed to parameter and pass to antenna servo system, so that transmitting-receiving sky Line can effectively point to target area.This method is disadvantageous in that, before carrying out antenna beam sensing control, and must Point target WGS-84 coordinate parameters accurately (including longitude, latitude and height), and in the method, transmitter must be got Using same coordinates transformation method with receiver, the WGS-84 coordinate of point target is indispensable in its coordinates transformation method Input parameter；And in practice, double-base SAR need to carry out imaging to arbitrary region, and when these regions coordinate accurately When location parameter is the unknown, the party's rule cannot process；Additionally, the method is due to only to having the point determining coordinate position parameter Target area carries out imaging, its range of application critical constraints, thus the spacing synchronization process of above-mentioned double-base SAR exists target Particular location coordinate require accurately, it is difficult to obtain the disadvantages such as effective application in practice

Summary of the invention

The invention aims to overcome problem present in background technology spacing synchronization process, propose a kind of unknown object position The spacing synchronization process of the double-base synthetic aperture radar of coordinate, transmitter antenna only need to be pointed to and intend imaging (location) by the method Center, target area, receiver i.e. can follow up automatically, makes receiver antenna point to and points to consistent with transmitter antenna, and transmitter Different processing method (algorithm) will be used, to target location during to reduce double-base synthetic aperture radar spatial synchronization from receiver The requirement of parameter, reduces the double-base synthetic aperture radar spatial synchronization dependency to point target position coordinate parameters, reaches effective Improve the efficiency of double-base SAR spatial synchronization, it is achieved can to spatial synchronization during target position coordinates the unknown accurately and realization The purposes such as broad practice.

For convenience of follow-up, double-base SAR spacing synchronization process is described, existing its definition clear and definite to following term:

1. terrestrial coordinate system: this coordinate origin in the earth's core, z_eAxle is along the direction of earth's axis, x_e、y_eAxle plane under the line In, wherein x_eAxle intersects with zero degree meridian, as shown in Figure 1.

2. geographic coordinate system: this coordinate origin is positioned at carrier barycenter, wherein z_gCoordinate axes is along the direction of local geographic vertical, separately Outer two axles in the horizontal plane at carrier place respectively along as ground weft (x_gAxle) and warp (y_gAxle) tangential direction, also cry Do sky, northeast (ENU) rectangular coordinate system.As shown in MENU coordinate in Fig. 1, in figure, M is a bit on ground, and angle λ represents a little The longitude of M, angle L represents the latitude of a M.

3. carrier coordinate system (b): this coordinate origin overlaps with the barycenter of carrier is consistent with the origin position of geographic coordinate system； For aircraft or cruise carrier, its x_bAxle along carrier transverse axis to the right, y_bAxle along before carrier Y-direction, z_bAxle is along load Upwards, i.e. coordinate system " on before the right side ", as in figure 2 it is shown, wherein β for body vertical pivot_SAnd β_PIt is respectively the orientation under carrier coordinate system Angle and the angle of pitch, it is illustrated that middle β_SFor on the occasion of, β_PFor negative value；And for being respectively directed to transmitter and receiver, β_TSAnd β_TPPoint Wei azimuth under transmitter carrier coordinate system and the angle of pitch, β_RSAnd β_RPIt is respectively the azimuth under receiver carrier coordinate system And the angle of pitch, it is illustrated that in be all on the occasion of.

4. attitude of carrier angle (ψ, θ, γ):

1. course angle (ψ): definition carrier (aircraft or cruise vehicle) rotates around vertical line direction, and the longitudinal axis of carrier is at water The angle between projection and geographical north orientation in plane is course angle, and numerical value, with geographical north orientation as starting point, is just clockwise, Its definition territory is 0 °～360 °.

2. the angle of pitch (θ): the angle that definition carrier rotates, around transverse horizontal axis, the longitudinal axis and the vertical equity axle produced is the angle of pitch, The angle of pitch, with trunnion axis as starting point, is just upwards, is negative downwards, defines-90 °～90 ° of territory.

3. roll angle (γ): definition carrier is roll angle around the longitudinal axis, relative to the corner of vertical plane, counts from vertical plane, Right deviation is just, "Left"-deviationist is negative, and definition territory is-180 °～180 °；It is the definition schematic diagram of attitude angle as shown in Figure 3.

5. navigation attitude instrument: navigation attitude instrument is disposed upon a kind of navigator on carrier (aircraft or cruise vehicle), it is flight Body provides multinomial information, wherein needs the information used to include in spatial synchronization system: carrier positions information (longitude, latitude And height) and attitude of carrier information (course angle, the angle of pitch and roll angle).

6. antenna servo system: a kind of equipment controlling antenna sensing that antenna servo system is disposed upon on carrier, it includes number Word signal processing module and two modules of servomotor.Wherein, two kinds of information of digital signal processing module reception: the angle of pitch and side Parallactic angle；After digital signal processing module gets both information, it is by certain operation control servomotor, so that sky Line points to the direction set.

The solution of the present invention is to intend penetrating the parameter of machine (platform) carry out sending out, receiving before imaging region determining that antenna points to Initialization processes, and wherein the initiation parameter of transmitter includes: [λ_T L_T H_T], the most corresponding longitude of transmitter, latitude and height Degree, [ψ_T θ_T γ_T] distinguish the corresponding course angle of transmitter, the angle of pitch and roll angle；The initiation parameter of receiver includes: [λ_R L_R H_R], the most corresponding longitude of receiver, latitude and height, [ψ_R θ_R γ_R] respectively corresponding receiver course angle, bow The elevation angle and roll angle；After initialization completes: transmitter complete again to its antenna point to intend center, imageable target region control and Its relevant processing method (algorithm), the parameter of the target area that receiver then transmits according to transmitter completes its reception antenna Point to control, make receiver antenna point to transmitter antenna sensing consistent；Sit accurately from without the point target intending imaging Cursor position parameter can complete the spatial synchronization that receiver antenna points to transmitter antenna.Thus double-base synthetic aperture of the present invention The spacing synchronization process of radar includes:

Initialization processes: first transmitter, receiver platform parameters are carried out corresponding initialization process respectively, wherein: launch Machine initiation parameter includes: the longitude [λ of transmitter itself_T], latitude [L_T], highly [H_T], course angle [ψ_T], the angle of pitch [θ_T] And roll angle [γ_T]；The initiation parameter of receiver includes: the longitude [λ of receiver itself_R], latitude [L_R], highly [H_R], boat To angle [ψ_R], the angle of pitch [θ_R] and roll angle [γ_R]；Hereafter transmitter A sequentially includes the following steps: respectively with receiver B

Transmitter A:

Step A₁. determine the unit direction vector that antenna points toTransmitter carrier coordinate system is inputted to transmitter antenna servosystem Azimuthal angle beta in the sensing of lower antenna_TSAnd pitching angle beta_TPParameter, and determine that this antenna points to parameter under transmitter carrier coordinate system Unit direction vector

Step A₂. the conversion that carrier coordinate system is vectorial with geographic coordinate system: by the unit direction vector under transmitter carrier coordinate systemPass through transition matrixIt is converted into the vector under transmitter geographic coordinate system

Step A₃. determine the transmitter vector to center, target area: according to the vertical height of transmitter to ground and pass through step A₂Vector under gained transmitter geographic coordinate systemDetermine that under geographic coordinate system, transmitter is to the vector at center, target area

Step A₄. geographic coordinate system and the conversion of terrestrial coordinate system: by the vector under geographic coordinate systemPass through transition matrix It is converted into the vector under terrestrial coordinate system

Step A₅. determine transmitter vector under terrestrial coordinate systemLongitude, latitude and height parameter according to transmitter, Determine transmitter vector under terrestrial coordinate system

Step A₆. determine the position vector at center, target areaAccording to vectorAnd vectorMesh under spherical coordinate system definitely The position vector of mark regional centerIt is then passed through data transmission channel, by this position vectorIt is sent to receiver；

Receiver B:

Step B₁. determine that receiver is in terrestrial coordinate system position vectorAccording to receiver initiation parameter, by longitude therein, Latitude and height parameter are converted into the position vector under terrestrial coordinate system

Step B₂. determine that receiver points to center, target area and points to vectorAccording to receive by transmitter step A₆Send Center, target area vectorWith receiver in terrestrial coordinate system position vectorUnder spherical coordinate system, receiver points to definitely The sensing vector at center, target area

Step B₃. determine the sensing vector under geographic coordinate systemBase area spherical coordinate system is to the conversion of receiver geographic coordinate system MatrixBy step B₂Gained points to vectorThe sensing vector being converted under receiver geographic coordinate system

Step B₄. determine the sensing vector under carrier coordinate systemIt is tied to receiver carrier coordinate system according to receiver geographical coordinate Transition matrixBy the sensing vector under geographic coordinate systemThe sensing vector being converted under receiver carrier coordinate system

Step B₅. complete the spatial synchronization that receiver antenna points to transmitter antenna: according to step B₄Gained points to vectorReally Determine the azimuthal angle beta that under receiver carrier coordinate system, receiver antenna points to_RSWith pitching angle beta_RP, then by this azimuthal angle beta_RSAnd pitching Angle beta_RPInput receiver antenna servo system also completes the spatial synchronization that receiver antenna is consistent with transmitter antenna sensing.

In step A₂Described in transition matrixFor:

$C_b^g=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T+\sin {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T& \cos {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T& \sin {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T-\cos {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T\\ -\cos {\mathrm{\γ}}_T\sin {\mathrm{\ψ}}_T+\sin {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T& \cos {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T& -\sin {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T-\cos {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T\\ -\sin {\mathrm{\γ}}_T\cos {\mathrm{\θ}}_T& {\sin \mathrm{\θ}}_T& \cos {\mathrm{\γ}}_T\cos {\mathrm{\θ}}_T\end{array}\right]$

In formula: ψ_T、θ_T、γ_TIt is respectively the course angle of transmitter, the angle of pitch and roll angle.

Step A₄Described in transition matrixFor:

$C_g^e=\left[\begin{array}{ccc}-{\sin \mathrm{\λ}}_T& -\sin L_T\cos {\mathrm{\λ}}_T& \cos L_T\cos {\mathrm{\λ}}_T\\ \cos {\mathrm{\λ}}_T& -\sin L_T\sin {\mathrm{\λ}}_T& \cos L_T\sin {\mathrm{\λ}}_T\\ 0& \cos L_T& \sin L_T\end{array}\right]$

Wherein: λ_TAnd L_TRepresent longitude and the latitude of transmitter position respectively.

In step A₅Described according to longitude, latitude and the height parameter of transmitter, determine transmitter under terrestrial coordinate system to AmountFor:

$\stackrel{\→}{A5}={\left[\begin{array}{ccc}{A}_{51}& A_{52}& A_{53}\end{array}\right]}^T$

$={\left[\begin{array}{ccc}(H_T+R_{\mathrm{NT}})\cos L_T\cos {\mathrm{\λ}}_T& (H_T+R_{\mathrm{NT}})\cos L_T\sin {\mathrm{\λ}}_T& [R_{\mathrm{NT}}{(1-f)}^2+H_T]\sin \end{array}{L}_T\right]}^T$

Wherein: $\left\{\begin{array}{c}f=\frac{R_e-R_p}{R_e}\\ R_{\mathrm{NT}}\≈R_e(1+f{\sin }^2{L}_T)\end{array}\right.$

In above-mentioned formula: λ_T、L_T、H_TIt is respectively the longitude of transmitter, latitude and height above sea level, R_NTFor transmitter institute on ground At the radius of curvature in prime vertical of position, f is the ovality of earth ellipsoid, R_e=6378136m is equatorial plane radius (major radius), R_p=6356755m is pole axis radius (short radius).

In step A₆Described in obtain the position vector at center, target area under terrestrial coordinate systemIts vector is:

$\stackrel{\→}{A6}={\left[\begin{array}{ccc}{A}_{61}& A_{62}& A_{63}\end{array}\right]}^T=\stackrel{\→}{A4}+\stackrel{\→}{A5}={\left[\begin{array}{ccc}{A}_{41}+A_{51}& A_{42}+A_{52}& A_{43}+A_{53}\end{array}\right]}^T.$

Step B₁Described in the longitude in receiver initiation parameter, latitude and height parameter are converted into the position under terrestrial coordinate system Put vectorIts position vectorFor:

$\stackrel{\→}{B1}={\left[\begin{array}{ccc}{B}_{11}& B_{12}& B_{13}\end{array}\right]}^T$

$={\left[\begin{array}{ccc}(H_R+R_{\mathrm{NR}})\cos L_R\cos {\mathrm{\λ}}_R& (H_R+R_{\mathrm{NR}})\cos L_R\sin {\mathrm{\λ}}_R& [R_{\mathrm{NR}}{(1-f)}^2+H_R]\sin \end{array}{L}_R\right]}^T$

Wherein: R_NR≈R_e(1+f sin² L_R) it is the radius of curvature in prime vertical of receiver position, λ on ground_R、L_R、H_RRespectively For longitude, latitude and the height above sea level of receiver, f is the ovality of earth ellipsoid, R_eFor equatorial plane radius (major radius), R_p For pole axis radius (short radius).

Step B₃Described in base area spherical coordinate system to the transition matrix of receiver geographic coordinate systemBy step B₂Gained points to VectorThe sensing vector being converted under receiver geographic coordinate systemWherein transition matrixFor:

$C_e^g=\left[\begin{array}{ccc}-\sin {\mathrm{\λ}}_R& \cos {\mathrm{\λ}}_R& 0\\ -\sin L_R\cos {\mathrm{\λ}}_R& -\sin L_R\sin {\mathrm{\λ}}_R& \cos L_R\\ \cos L_R\cos {\mathrm{\λ}}_R& \cos L_R\sin {\mathrm{\λ}}_R& \sin L_R\end{array}\right]$

The then vector of the sensing under receiver geographic coordinate system

Step B₄Described in receiver geographical coordinate be tied to the transition matrix of receiver carrier coordinate systemBy under geographic coordinate system Sensing vectorThe sensing vector being converted under receiver carrier coordinate systemIts transition matrixFor:

$C_g^b=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R+\sin {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& -\cos {\mathrm{\γ}}_R\sin {\mathrm{\ψ}}_R+\sin {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& -\sin {\mathrm{\γ}}_R\cos {\mathrm{\θ}}_R\\ \cos {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& \cos {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& \sin {\mathrm{\θ}}_R\\ \sin {\mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R-\cos {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& -{\sin \mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R-\cos {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& \cos {\mathrm{\γ}}_R\cos {\mathrm{\θ}}_R\end{array}\right]$

Wherein: ψ_R、θ_R、^γ _RIt is respectively the course angle of receiver, the angle of pitch and roll angle；

The then vector under receiver carrier coordinate systemFor: $\stackrel{\→}{B4}={\left[\begin{array}{ccc}{B}_{41}& B_{42}& B_{43}\end{array}\right]}^T=C_g^b\×\stackrel{\→}{B3}.$

Transmitter of the present invention is not required to be known a priori by the WGS-84 coordinate of target area central point, the most do not use target area central point WGS-84 coordinate, but use a kind of spacing synchronization process pointing to based on transmitter antenna and intending imaging (location) target area； That is transmitter only need to control antenna and point to, making antenna point to the center of a certain target area, receiver will automatically follow up, make Receiver antenna points to and points to consistent with transmitter antenna, and transmitter uses different coordinate transformation methods (to calculate from receiver Method), in carrying out Coordinate Conversion, be not required to know plan imageable target point position coordinate parameters accurately, can complete receiver antenna with The spatial synchronization that transmitter antenna points to；Thus there is the efficiency that can be effectively increased double-base SAR spatial synchronization, degree of accuracy is relatively Height, the features such as offline mode is flexible, the most extensive application.Overcome the position coordinates requirement to target that background technology exists Accurately, Coordinate Conversion (algorithm) must input the WGS-84 of impact point, and the very flexible of the offline mode existed, difficulty To obtain the defects such as effective application in practice.

Accompanying drawing illustrates:

Fig. 1 is terrestrial coordinate system and geographic coordinate system schematic diagram；

Fig. 2 is carrier coordinate system and antenna sensing schematic diagram；

Fig. 3 is the definition schematic diagram at attitude of carrier angle, the angle of pitch, roll angle and the course angle in figure be on the occasion of；

Fig. 4 is double-base SAR spatial synchronization view；

Fig. 5 is 1000 Monte Carlo simulations result figure (coordinate diagram) of the sending and receiving carrier aircraft beam center offset deviation on ground.

Detailed description of the invention:

Initialization processes: wherein the initiation parameter of transmitter is: azimuth and the angle of pitch (β_TS, β_TP)=(41.04 ° ,-88.27 °)； Longitude, latitude and height above sea level (λ_T, L_T, H_T)=(104 °, 30 °, 5111m)；Course angle, the angle of pitch and roll Angle (ψ_T, θ_T, γ_T)=(90 °, 0 °, 0 °)；Corresponding ground height above sea level H under transmitter orthographic projection_g=250m.Receive The initiation parameter of machine is: longitude, latitude and height above sea level (λ_R, L_R, H_R)=(104 °, 30 °, 4361m)；Boat To angle, the angle of pitch and roll angle (ψ_R, θ_R, γ_R)=(90 °, 0 °, 0 °)；Corresponding ground height above sea level under receiver orthographic projection Degree H_g=250m；Hereafter transmitter A sequentially includes the following steps: respectively with receiver B

Transmitter A:

Step A₁. determine the unit direction vector that antenna points to(angle) parameter is pointed to antenna servo system input antenna (β_TS, β_TP), complete the transmitter antenna beam in this direction；As in figure 2 it is shown, transmitter antenna will point to it Under carrier coordinate system, direction is (β_TS, β_TP) a certain regional center, unit direction under carrier coordinate system, this direction to Amount is: $\stackrel{\→}{A1}={[\cos {\mathrm{\β}}_{\mathrm{TP}}\cos {\mathrm{\β}}_{\mathrm{TS}},\cos {\mathrm{\β}}_{\mathrm{TP}}\sin {\mathrm{\β}}_{\mathrm{TS}},-\sin {\mathrm{\β}}_{\mathrm{TP}}]}^T;$

Step A₂. the conversion that carrier coordinate system is vectorial with geographic coordinate system: by the unit direction vector under transmitter carrier coordinate systemIt is converted into the vector under transmitter geographic coordinate systemTransition matrix is:

$C_b^g=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T+\sin {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T& \cos {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T& \sin {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T-\cos {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\sin {\mathrm{\ψ}}_T\\ -\cos {\mathrm{\γ}}_T\sin {\mathrm{\ψ}}_T+\sin {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T& \cos {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T& -\sin {\mathrm{\γ}}_T\cos {\mathrm{\ψ}}_T-\cos {\mathrm{\γ}}_T\sin {\mathrm{\θ}}_T\cos {\mathrm{\ψ}}_T\\ -\sin {\mathrm{\γ}}_T\cos {\mathrm{\θ}}_T& {\sin \mathrm{\θ}}_T& \cos {\mathrm{\γ}}_T\cos {\mathrm{\θ}}_T\end{array}\right]$

Wherein: ψ_T、θ_T、γ_TBe respectively the course angle of transmitter, the angle of pitch and roll angle, then under transmitter geographic coordinate system to AmountCan be expressed as:

$\stackrel{\→}{A2}={\left[\begin{array}{ccc}{A}_{21}& A_{22}& A_{23}\end{array}\right]}^T=C_b^g\×\stackrel{\→}{A1}$

Step A₃. determine the transmitter vector to target area central point: according to the vertical height of transmitter to ground and by step Rapid A₂Vector under gained transmitter geographic coordinate systemDetermine the transmitter vector to center, target areaThat is:

$\stackrel{\→}{A3}={\left[\begin{array}{ccc}{A}_{31}& A_{32}& A_{33}\end{array}\right]}^T=H_1\×{\left[\begin{array}{ccc}1& \frac{A_{22}}{A_{21}}& \frac{A_{23}}{A_{21}}\end{array}\right]}^T$

Wherein: under transmitter orthographic projection, the height above sea level of corresponding ground is H_g=250m, acquired transmitting from transmitter navigation attitude instrument The height above sea level of machine is H_T=5111m, then transmitter to the vertical height on ground is:

H₁=H_T-H_g=4861m

Step A₄. the conversion that geographic coordinate system is vectorial with terrestrial coordinate system: by vectorIt is converted into the vector under terrestrial coordinate systemTransition matrixFor:

$C_g^e=\left[\begin{array}{ccc}-{\sin \mathrm{\λ}}_T& -\sin L_T\cos {\mathrm{\λ}}_T& \cos L_T\cos {\mathrm{\λ}}_T\\ \cos {\mathrm{\λ}}_T& -\sin L_T\sin {\mathrm{\λ}}_T& \cos L_T\sin {\mathrm{\λ}}_T\\ 0& \cos L_T& \sin L_T\end{array}\right]$

Wherein, λ_TAnd L_TRepresent longitude and the latitude of transmitter position respectively；So, vectorCan be expressed as:

$\stackrel{\→}{A4}={\left[\begin{array}{ccc}{A}_{41}& A_{42}& A_{43}\end{array}\right]}^T=C_g^e\×\stackrel{\→}{A3};$

Step A₅. determine transmitter vector under terrestrial coordinate systemThe step for remain a need for utilizing obtain on navigation attitude instrument to send out Penetrating machine longitude, latitude and elevation information, it is expressed as [λ_T L_T H_T], thenFor:

$\stackrel{\→}{A5}={\left[\begin{array}{ccc}{A}_{51}& A_{52}& A_{53}\end{array}\right]}^T$

$={\left[\begin{array}{ccc}(H_T+R_{\mathrm{NT}})\cos L_T\cos {\mathrm{\λ}}_T& (H_T+R_{\mathrm{NT}})\cos L_T\sin {\mathrm{\λ}}_T& [R_{\mathrm{NT}}{(1-f)}^2+H_T]\sin \end{array}{L}_T\right]}^T$

Wherein: $\left\{\begin{array}{c}f=\frac{R_e-R_p}{R_e}\\ R_{\mathrm{NT}}\≈R_e(1+f{\sin }^2{L}_T)\end{array}\right.$

In above-mentioned formula: H_THeight above sea level, R for transmitter_NTFor the radius of curvature in prime vertical of transmitter position on ground, R_e=6378136m is equatorial plane radius (major radius), R_p=6356755m is pole axis radius (short radius)；

Step A₆. target location vector under terrestrial coordinate systemFor:

$\stackrel{\→}{A6}={\left[\begin{array}{ccc}{A}_{61}& A_{62}& A_{63}\end{array}\right]}^T=\stackrel{\→}{A4}+\stackrel{\→}{A5}$

$={\left[\begin{array}{ccc}{A}_{41}+A_{51}& A_{42}+A_{52}& A_{43}+A_{53}\end{array}\right]}^T$

Can be obtained by computing $\stackrel{\→}{A6}={\left[\begin{array}{ccc}-1337565.935& 5364285.097& 3170406.385\end{array}\right]}^T;$ And by this target location vectorPass through Number passes passage and passes to receiver；

Receiver B:

Step B₁. determine that receiver is in terrestrial coordinate system position vectorAccording to the initiation parameter of receiver, by receiver Longitude, latitude and height parameter are converted into the position vector under terrestrial coordinate systemIts position vectorFor:

$\stackrel{\→}{B1}={\left[\begin{array}{ccc}{B}_{11}& B_{12}& B_{13}\end{array}\right]}^T$

$={\left[\begin{array}{ccc}(H_R+R_{\mathrm{NR}})\cos L_R\cos {\mathrm{\λ}}_R& (H_R+R_{\mathrm{NR}})\cos L_R\sin {\mathrm{\λ}}_R& [R_{\mathrm{NR}}{(1-f)}^2+H_R]\sin \end{array}{L}_R\right]}^T$

Wherein: R_NR≈R_e(1+f sin²L_R) it is the radius of curvature in prime vertical of receiver position on ground, f is the ellipse of earth ellipsoid Degree, R_eFor equatorial plane radius (major radius), R_pFor pole axis radius (short radius)；

Step B₂. determine that receiver points to center, target area and points to vectorAccording to receive by transmitter step A₆Send Center, target area vectorWith receiver in terrestrial coordinate system position vectorUnder spherical coordinate system, receiver points to definitely The sensing vector at center, target areaIt points to vectorFor:

$\stackrel{\→}{B2}={\left[\begin{array}{ccc}{B}_{21}& B_{22}& B_{33}\end{array}\right]}^T=\stackrel{\→}{A6}-\stackrel{\→}{B1}={\left[\begin{array}{ccc}{A}_{61}-B_{11}& A_{62}-B_{12}& A_{63}-B_{13}\end{array}\right]}^T;$

Step B₃. determine the sensing vector under geographic coordinate systemBase area spherical coordinate system is to the conversion of receiver geographic coordinate system MatrixBy step B₂Gained points to vectorThe sensing vector being converted under receiver geographic coordinate systemIts transition matrixFor:

$C_e^g=\left[\begin{array}{ccc}-\sin {\mathrm{\λ}}_R& \cos {\mathrm{\λ}}_R& 0\\ -\sin L_R\cos {\mathrm{\λ}}_R& -\sin L_R\sin {\mathrm{\λ}}_R& \cos L_R\\ \cos L_R\cos {\mathrm{\λ}}_R& \cos L_R\sin {\mathrm{\λ}}_R& \sin L_R\end{array}\right]$

The then vector of the sensing under receiver geographic coordinate systemFor:

$\stackrel{\→}{B3}={\left[\begin{array}{ccc}{B}_{31}& B_{32}& B_{33}\end{array}\right]}^T=C_e^g\×\stackrel{\→}{B2};$

Step B₄. determine the sensing vector under carrier coordinate systemIt is tied to receiver carrier coordinate system according to receiver geographical coordinate Transition matrixBy the sensing vector under geographic coordinate systemThe sensing vector being converted under receiver carrier coordinate system Transition matrixFor:

$C_g^b=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R+\sin {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& -\cos {\mathrm{\γ}}_R\sin {\mathrm{\ψ}}_R+\sin {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& -\sin {\mathrm{\γ}}_R\cos {\mathrm{\θ}}_R\\ \cos {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& \cos {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& \sin {\mathrm{\θ}}_R\\ \sin {\mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R-\cos {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\sin {\mathrm{\ψ}}_R& -{\sin \mathrm{\γ}}_R\cos {\mathrm{\ψ}}_R-\cos {\mathrm{\γ}}_R\sin {\mathrm{\θ}}_R\cos {\mathrm{\ψ}}_R& \cos {\mathrm{\γ}}_R\cos {\mathrm{\θ}}_R\end{array}\right]$

Wherein: ψ_R、θ_R、γ_RBe respectively the course angle of receiver, the angle of pitch and roll angle, then under receiver carrier coordinate system to AmountFor:

$\stackrel{\→}{B4}={\left[\begin{array}{ccc}{B}_{41}& B_{42}& B_{43}\end{array}\right]}^T=C_g^b\×\stackrel{\→}{B3};$

Step B₅. determine that receiver antenna points to angle: according to step B₄Gained points to vectorDetermine receiver carrier coordinate system The azimuthal angle beta that lower receiver antenna points to_RSWith pitching angle beta_RPFor:

$\left\{\begin{array}{c}{\mathrm{\β}}_{\mathrm{RS}}=\arctan \frac{B_{42}}{B_{41}}\\ {\mathrm{\β}}_{\mathrm{RP}}=\arctan \frac{B_{43}}{\sqrt{B_{41}^2+B_{42}^2}}\end{array}\right.$

(β can be obtained by computer sim-ulation_RS, β_RP)=(41.04 ° ,-87.95 °)；Again by gained azimuthal angle beta_RSWith pitching angle beta_RP Value input receiver antenna servo system, and then complete the spatial synchronization that receiver antenna is consistent with transmitter antenna sensing.

Simulation run: carry out 1000 Monte Carlo simulations according to above-mentioned steps, the parameter that the present invention provides can calculate transmitting Machine, the receiver beam diameter on ground is respectively as follows:

$\left\{\begin{array}{c}{d}_t=\sqrt{{\left(R_T\sin {\mathrm{\β}}_{\mathrm{TP}}\right)}^2+{\left(R_T\cos {\mathrm{\β}}_{\mathrm{TP}}\cos {\mathrm{\β}}_{\mathrm{TS}}\right)}^2}\×[\tan ({\mathrm{\α}}_T+\frac{{\mathrm{\φ}}_T}{2})-\tan ({\mathrm{\α}}_T-\frac{{\mathrm{\φ}}_T}{2})]\≈280.2339m\\ d_r=\sqrt{{\left(R_R\sin {\mathrm{\β}}_{22}\right)}^2+{\left(R_R\cos {\mathrm{\β}}_{\mathrm{RP}}\cos {\mathrm{\β}}_{\mathrm{RS}}\right)}^2}\×[\tan ({\mathrm{\α}}_R+\frac{{\mathrm{\φ}}_R}{2})-\tan ({\mathrm{\α}}_R-\frac{{\mathrm{\φ}}_R}{2})]\≈252.2761m\\ {\mathrm{\α}}_T=\arcsin \left[\cos {\mathrm{\β}}_{\mathrm{TP}}\sin {\mathrm{\β}}_{\mathrm{TS}}\right]\\ {\mathrm{\α}}_R=\arcsin \left[{\cos \mathrm{\β}}_{\mathrm{RP}}\sin {\mathrm{\β}}_{\mathrm{RS}}\right]\end{array}\right.$

Wherein: φ_T(R)=3.3 ° be transmitter, receiver antenna beam angular breadth (assume orientation to distance to antenna beam angular width Degree is the same), R_T(R)Distance for transmitter (receiver) to impact point.Assume that carrier positions error is for [Δ λ Δ L Δ H], wherein Δ λ It is (-0.00001 °, 0.00001 °) that the interval of Δ H is (-1,1) with the interval of Δ L；Attitude of carrier error [Δ ψ Δ θ Δ γ], its Interval is (-0.01 °, 0.01 °).Fig. 5 is 1000 Monte Carlo simulation figures of the transmitting-receiving beam center offset deviation on ground, can With find out its offset deviation within the scope of 8m, offset deviation much smaller than transmitter, receiver at the beam diameter on ground, thus may be used To find out that the specific embodiment of the invention has higher degree of accuracy.

Claims (6)

1. a spacing synchronization process for the double-base synthetic aperture radar that target location coordinate is unknown, including:

Initialization processes: first transmitter, receiver platform parameters are carried out corresponding initialization process respectively, wherein: launch Machine initiation parameter includes: the longitude [λ of transmitter itself_T], latitude [L_T], highly [H_T], course angle [ψ_T], the angle of pitch [θ_T] And roll angle [γ_T]；The initiation parameter of receiver includes: the longitude [λ of receiver itself_R], latitude [L_R], highly [H_R], boat To angle [ψ_R], the angle of pitch [θ_R] and roll angle [γ_R]；Hereafter transmitter A is carried out the most according to the following steps with receiver B；

Transmitter A:

Step A₁. determine the unit direction vector that antenna points toTransmitter carrier coordinate system is inputted to transmitter antenna servosystem Azimuthal angle beta in the sensing of lower antenna_TSAnd pitching angle beta_TPParameter, and determine that this antenna points to parameter under transmitter carrier coordinate system Unit direction vectorIts unit direction vector

Step A₂. the conversion that carrier coordinate system is vectorial with geographic coordinate system: by the unit direction vector under transmitter carrier coordinate systemPass through transition matrixIt is converted into the vector under transmitter geographic coordinate systemDescribed transition matrixFor:

$C_g^b=\left[\begin{array}{ccc}{\mathrm{cos\γ}}_T{\mathrm{cos\ψ}}_T+{\mathrm{sin\γ}}_T{\mathrm{sin\θ}}_T{\mathrm{sin\ψ}}_T& {\mathrm{cos\θ}}_T{\mathrm{sin\ψ}}_T& {\mathrm{sin\γ}}_T{\mathrm{cos\ψ}}_T-{\mathrm{cos\γ}}_T{\mathrm{sin\θ}}_T{\mathrm{sin\ψ}}_T\\ -{\mathrm{cos\γ}}_T{\mathrm{sin\ψ}}_T+{\mathrm{sin\γ}}_T{\mathrm{sin\θ}}_T{\mathrm{cos\ψ}}_T& {\mathrm{cos\θ}}_T{\mathrm{cos\ψ}}_T& -{\mathrm{sin\γ}}_T{\mathrm{cos\ψ}}_T-{\mathrm{cos\γ}}_T{\mathrm{sin\θ}}_T{\mathrm{cos\ψ}}_T\\ -{\mathrm{sin\γ}}_T{\mathrm{cos\θ}}_T& {\mathrm{sin\θ}}_T& {\mathrm{cos\γ}}_T{\mathrm{cos\θ}}_T\end{array}\right]$

In formula: ψ_T、θ_T、γ_TIt is respectively the course angle of transmitter, the angle of pitch and roll angle；

And the vector under transmitter geographic coordinate system

Step A₃. determine the transmitter vector to center, target area: according to the vertical height of transmitter to ground and pass through step A₂Vector under gained transmitter geographic coordinate systemDetermine that under geographic coordinate system, transmitter is to the vector at center, target area

Step A₄. geographic coordinate system and the conversion of terrestrial coordinate system: by the vector under geographic coordinate systemPass through transition matrix It is converted into the vector under terrestrial coordinate system

Step A₅. determine transmitter vector under terrestrial coordinate systemLongitude, latitude and height parameter according to transmitter, Determine transmitter vector under terrestrial coordinate system

Step A₆. determine the position vector at center, target areaAccording to vectorAnd vectorMesh under spherical coordinate system definitely The position vector of mark regional centerIts vector

It is then passed through data transmission channel, by this position vectorIt is sent to receiver；

Receiver B:

Step B₁. determine that receiver is in terrestrial coordinate system position vectorAccording to receiver initiation parameter, by longitude therein, Latitude and height parameter are converted into the position vector under terrestrial coordinate system

Step B₂. determine that receiver points to center, target area and points to vectorAccording to receive by transmitter step A₆Send Center, target area vectorWith receiver in terrestrial coordinate system position vectorUnder spherical coordinate system, receiver points to definitely The sensing vector at center, target area

Step B₃. determine the sensing vector under geographic coordinate systemBase area spherical coordinate system is to the conversion of receiver geographic coordinate system MatrixBy step B₂Gained points to vectorThe sensing vector being converted under receiver geographic coordinate system

Step B₄. determine the sensing vector under carrier coordinate systemIt is tied to receiver carrier coordinate system according to receiver geographical coordinate Transition matrixBy the sensing vector under geographic coordinate systemThe sensing vector being converted under receiver carrier coordinate system

Step B₅. complete the spatial synchronization that receiver antenna points to transmitter antenna: according to step B₄Gained points to vectorReally Determine the azimuthal angle beta that under receiver carrier coordinate system, receiver antenna points to_RSWith pitching angle beta_RP, then by this azimuthal angle beta_RSAnd pitching Angle beta_RPInput receiver antenna servo system also completes the spatial synchronization that receiver antenna is consistent with transmitter antenna sensing.

2. the spacing synchronization process of the double-base synthetic aperture radar that target location coordinate as described in claim 1 is unknown, its feature It is step A₄Described in transition matrixFor:

$C_g^e=\left[\begin{array}{ccc}-{\mathrm{sin\λ}}_T& -{\mathrm{sinL}}_T{\mathrm{cos\λ}}_T& {\mathrm{cosL}}_T{\mathrm{cos\λ}}_T\\ {\mathrm{cos\λ}}_T& -{\mathrm{sinL}}_T{\mathrm{sin\λ}}_T& {\mathrm{cosL}}_T{\mathrm{sin\λ}}_T\\ 0& {\mathrm{cosL}}_T& {\mathrm{sinL}}_T\end{array}\right]$

Wherein: λ_TAnd L_TRepresent longitude and the latitude of transmitter position respectively.

3. the spacing synchronization process of the double-base synthetic aperture radar that target location coordinate as described in claim 1 is unknown, its feature It is step A₅Described according to longitude, latitude and the height parameter of transmitter, determine transmitter vector under terrestrial coordinate systemFor:

$\begin{array}{c}\stackrel{\→}{A5}={\left[\begin{array}{ccc}{A}_{51}& A_{52}& A_{53}\end{array}\right]}^T\\ ={\left[\begin{array}{ccc}(H_T+R_{NT}){\mathrm{cosL}}_T{\mathrm{cos\λ}}_T& (H_T+R_{NT}){\mathrm{cosL}}_T{\mathrm{cos\λ}}_T& \[R_{NT}{(1-f)}^2+H_T\]{\mathrm{sinL}}_T\end{array}\right]}^T\end{array}$

Wherein:

In above-mentioned formula: λ_T、L_T、H_TIt is respectively the longitude of transmitter, latitude and height above sea level, R_NTFor transmitter institute on ground At the radius of curvature in prime vertical of position, f is the ovality of earth ellipsoid, R_e=6378136m is equatorial plane radius (major radius), R_p=6356755m is pole axis radius (short radius).

4. the spacing synchronization process of the double-base synthetic aperture radar that target location coordinate as described in claim 1 is unknown, its feature It is step B₁Described in the longitude in receiver initiation parameter, latitude and height parameter are converted into the position under terrestrial coordinate system Put vectorIts position vectorFor:

$\begin{array}{c}\stackrel{\→}{B1}={\left[\begin{array}{ccc}{B}_{11}& B_{12}& B_{13}\end{array}\right]}^T\\ ={\left[\begin{array}{ccc}(H_R+R_{HR}){\mathrm{cosL}}_R{\mathrm{cos\λ}}_R& (H_R+R_{HR}){\mathrm{cosL}}_R{\mathrm{cos\λ}}_R& \[R_{NR}{(1-f)}^2+H_R\]{\mathrm{sinL}}_R\end{array}\right]}^T\end{array}$

Wherein: R_NR≈R_e(1+f sin²L_R) it is the radius of curvature in prime vertical of receiver position, λ on ground_R、L_R、H_RRespectively For longitude, latitude and the height above sea level of receiver, f is the ovality of earth ellipsoid, R_eFor equatorial plane radius (major radius), R_p For pole axis radius (short radius).

5. the spacing synchronization process of the double-base synthetic aperture radar that target location coordinate as described in claim 1 is unknown, its feature It is step B₃Described in base area spherical coordinate system to the transition matrix of receiver geographic coordinate systemBy step B₂Gained points to VectorThe sensing vector being converted under receiver geographic coordinate systemWherein transition matrixFor:

$C_e^g=\left[\begin{array}{ccc}-{\mathrm{sin\λ}}_R& {\mathrm{cos\λ}}_R& 0\\ -{\mathrm{sinL}}_R{\mathrm{cos\λ}}_R& -{\mathrm{sinL}}_R{\mathrm{sin\λ}}_R& {\mathrm{cosL}}_R\\ {\mathrm{cosL}}_R{\mathrm{cos\λ}}_R& {\mathrm{cosL}}_R{\mathrm{sin\λ}}_R& {\mathrm{sinL}}_R\end{array}\right]$

The then vector of the sensing under receiver geographic coordinate system

6. the spacing synchronization process of the double-base synthetic aperture radar that target location coordinate as described in claim 1 is unknown, its feature It is step B₄Described in receiver geographical coordinate be tied to the transition matrix of receiver carrier coordinate systemBy under geographic coordinate system Sensing vectorThe sensing vector being converted under receiver carrier coordinate systemIts transition matrixFor:

$C_g^b=\left[\begin{array}{ccc}{\mathrm{cos\γ}}_R{\mathrm{cos\ψ}}_R+{\mathrm{sin\γ}}_R{\mathrm{sin\θ}}_R{\mathrm{sin\ψ}}_R& -{\mathrm{cos\γ}}_R{\mathrm{sin\ψ}}_R+{\mathrm{sin\γ}}_R{\mathrm{sin\θ}}_R{\mathrm{cos\ψ}}_R& -{\mathrm{sin\γ}}_R{\mathrm{cos\θ}}_R\\ {\mathrm{cos\θ}}_R{\mathrm{sin\ψ}}_R& {\mathrm{cos\θ}}_R{\mathrm{cos\ψ}}_R& {\mathrm{sin\θ}}_R\\ {\mathrm{sin\γ}}_R{\mathrm{cos\ψ}}_R-{\mathrm{cos\γ}}_R{\mathrm{sin\θ}}_R{\mathrm{sin\ψ}}_R& -{\mathrm{sin\γ}}_R{\mathrm{cos\ψ}}_R-{\mathrm{cos\γ}}_R{\mathrm{sin\θ}}_R{\mathrm{cos\ψ}}_R& {\mathrm{cos\γ}}_R{\mathrm{cos\θ}}_R\end{array}\right]$

Wherein: ψ_R、θ_R、γ_RIt is respectively the course angle of receiver, the angle of pitch and roll angle；

The then vector under receiver carrier coordinate systemFor: