CN104049241B

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

Info

Publication number: CN104049241B
Application number: CN201410231809.5A
Authority: CN
Inventors: 张顺生; 眭明; 张伟; 宗竹林; 康怀祺
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2014-05-29
Filing date: 2014-05-29
Publication date: 2017-01-04
Anticipated expiration: 2034-05-29
Also published as: CN104049241A

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

A Space Synchronization Method for Bistatic Synthetic Aperture Radar with Unknown Target Position Coordinates

技术领域technical field

本发明属于双基地合成孔径雷达(Bistatic Synthetic Aperture Radar，BiSAR)发射和接收技术领域；特别是一种不知道目标准确的坐标位置时的双基地合成孔径雷达的空间同步方法。The invention belongs to the technical field of bistatic synthetic aperture radar (Bistatic Synthetic Aperture Radar, BiSAR) transmission and reception; in particular, a method for spatial synchronization of bistatic synthetic aperture radar when the exact coordinate position of a target is unknown.

背景技术Background technique

合成孔径雷达(Synthetic Aperture Radar， SAR)具有全天时、全天候对地形地貌或地面目标进行高分辨率成像和精确定位的优异性能。然而，由于单基地SAR的发射平台和接收平台共用同一载体，其隐蔽性较差，容易受到敌方侦察并实施干扰。双基地合成孔径雷达(BistaticSynthetic Aperture Radar，BiSAR)的发射平台和接收平台安置在不同的载体上，其相比于单基地SAR，能够获取更丰富的目标信息和更远的作用距离。同时，由于接收平台处于无源接收状态，所以其抗干扰性能和安全性能也有很大提升。BiSAR所具有的诸多优异性能，使得其已成为近年来各国互相角逐的研究热点。Synthetic Aperture Radar (SAR) has excellent performance in all-day and all-weather high-resolution imaging and precise positioning of terrain features or ground targets. However, since the launching platform and receiving platform of monostatic SAR share the same carrier, its concealment is poor, and it is easy to be detected and interfered by the enemy. Bistatic Synthetic Aperture Radar (Bistatic Synthetic Aperture Radar, BiSAR) launch platform and receiving platform are placed on different carriers, which can obtain richer target information and longer range than monostatic SAR. At the same time, since the receiving platform is in a passive receiving state, its anti-interference performance and safety performance are also greatly improved. The many excellent properties of BiSAR have made it a research hotspot in recent years.

BiSAR由于采用了收、发分置的策略，所以必须配合相应的同步技术才能使其优异的性能得到发挥。也就是说，同步技术是BiSAR进行后端信号处理的前提。BiSAR的同步技术主要包括3个方面：空间同步、时间同步和频率/相位同步。这3大同步必须同时实现，缺一不可，其任何一方面的缺失都会导致严重的后果，甚至使BiSAR系统瘫痪。Because BiSAR adopts the strategy of receiving and sending separately, it must cooperate with the corresponding synchronization technology to make its excellent performance play. That is to say, synchronization technology is the prerequisite for back-end signal processing of BiSAR. The synchronization technology of BiSAR mainly includes three aspects: space synchronization, time synchronization and frequency/phase synchronization. These three major synchronizations must be realized at the same time, and all of them are indispensable. The lack of any one of them will lead to serious consequences, and even paralyze the BiSAR system.

BiSAR空间同步技术是指，在收、发分置的系统中，实时并有效地控制发射平台和接收平台的天线指向，使发射波束和接收波束同时照射到同一目标空间，以确保接收平台能够有效的接收到目标回波，即目标区域回波具有足够高的信噪比。在公布号为CN102967851A、名称为《一种双基地SAR的空间同步方法》的专利文件中公开了一种基于已知目标的坐标位置时的空间同步方法，该方法利用载机(体)平台的GPS空间坐标信息和姿态信息，按WGS-84坐标系、空间直角坐标系、地理坐标系、载体坐标系和雷达参考坐标系的顺序进行坐标变换，获取载机的天线指向控制参数，最后将天线指向参数传递给天线伺服系统，从而使得收发天线能够有效地指向目标区域。这种方法的不足之处在于，在进行天线波束指向控制之前，必须获取到点目标准确的WGS-84坐标参数(包括经度、纬度和高度)，且在该方法中，发射机和接收机采用同样的坐标转换算法，点目标的WGS-84坐标是其坐标转换算法中不可缺少的输入参数；而在实际运用中，双基地SAR需对任意区域进行成像，而当这些区域准确的坐标位置参数是未知时该方法则无法处理；此外，该方法由于只有对具有确定坐标位置参数的点目标区域进行成像，其应用范围严重受限，因而上述双基地SAR的空间同步方法存在对目标的具体位置坐标要求准确，难以在实际中得到有效应用等弊病BiSAR space synchronization technology refers to the real-time and effective control of the antenna pointing of the transmitting platform and the receiving platform in the system where the receiving and transmitting are separated, so that the transmitting beam and the receiving beam illuminate the same target space at the same time, so as to ensure that the receiving platform can effectively The target echo is received, that is, the target area echo has a sufficiently high signal-to-noise ratio. In the patent document with the publication number CN102967851A and the name "A Space Synchronization Method for Bistatic SAR", a space synchronization method based on the coordinate position of the known target is disclosed. GPS spatial coordinate information and attitude information, carry out coordinate transformation according to the order of WGS-84 coordinate system, spatial rectangular coordinate system, geographic coordinate system, carrier coordinate system and radar reference coordinate system, obtain the antenna pointing control parameters of the carrier aircraft, and finally place the antenna Pointing parameters are passed to the antenna servo system so that the transceiver antenna can be effectively pointed to the target area. The disadvantage of this method is that the accurate WGS-84 coordinate parameters (including longitude, latitude and altitude) of the point target must be obtained before antenna beam pointing control, and in this method, the transmitter and receiver adopt In the same coordinate transformation algorithm, the WGS-84 coordinates of point targets are indispensable input parameters in the coordinate transformation algorithm; in practice, bistatic SAR needs to image any area, and when the accurate coordinate position parameters of these areas This method cannot be processed when it is unknown; in addition, because this method only images point target areas with definite coordinate position parameters, its application range is severely limited, so the above-mentioned bistatic SAR space synchronization method has the specific position The coordinates are required to be accurate, and it is difficult to be effectively applied in practice.

发明内容Contents of the invention

本发明的目的是为了克服背景技术空间同步方法中存在的问题，提出一种未知目标位置坐标的双基地合成孔径雷达的空间同步方法，该方法只需将发射机天线指向拟成像(定位)目标区域中心，接收机即会自动跟进，使接收机天线指向与发射机天线指向一致，且发射机与接收机将采用不同的处理方法(算法)，以减少双基地合成孔径雷达空间同步时对目标位置参数的要求，降低双基地合成孔径雷达空间同步对点目标位置坐标参数的依赖性，达到有效提高双基地SAR空间同步的效率，实现对目标准确的位置坐标未知时的空间同步以及实现可广泛实际应用等目的。The purpose of the present invention is in order to overcome the problem existing in the background technology space synchronization method, proposes a kind of space synchronization method of the bistatic synthetic aperture radar of unknown target position coordinates, this method only needs to point the transmitter antenna to the imaginary image (positioning) target the center of the area, the receiver will automatically follow up to make the antenna pointing of the receiver consistent with the antenna pointing of the transmitter, and the transmitter and receiver will use different processing methods (algorithms) to reduce the impact of bistatic SAR space synchronization. Requirements for target position parameters reduce the dependence of bistatic synthetic aperture radar space synchronization on point target position coordinate parameters, effectively improve the efficiency of bistatic SAR space synchronization, realize space synchronization when the exact position coordinates of the target are unknown, and achieve reliable wide range of practical applications.

为方便后续对双基地SAR空间同步方法进行描述，现对以下术语明确其定义：In order to facilitate the subsequent description of the bistatic SAR space synchronization method, the following terms are now clearly defined:

1.地球坐标系：该坐标系原点在地心，z_e轴沿地球自转轴的方向，x_e、y_e轴在赤道平面内，其中x_e轴与零度子午线相交，如图1所示。1. Earth coordinate system: the origin of the coordinate system is at the center of the earth, the z _e axis is along the direction of the earth's rotation axis, the x _e and y _e axes are in the equatorial plane, and the x _e axis intersects the zero degree meridian, as shown in Figure 1.

2.地理坐标系：该坐标系原点位于载体质心，其中z_g坐标轴沿当地地理垂线的方向，另外两个轴在载体所在的水平面内分别沿当地纬线(x_g轴)和经线(y_g轴)的切线方向，也叫做东北天(ENU)直角坐标系。如图1中MENU坐标所示，图中M为地面上一点，角λ表示点M的经度，角L表示点M的纬度。2. Geographic coordinate system: the origin of the coordinate system is located at the center of mass of the carrier, where the z _g coordinate axis is along the direction of the local geographic vertical line, and the other two axes are respectively along the local latitude (x _g axis) and longitude (y axis) in the horizontal plane where the carrier is located. The tangent direction of the _g -axis), also known as the Northeast Sky (ENU) Cartesian coordinate system. As shown in the MENU coordinates in Figure 1, M in the figure is a point on the ground, the angle λ represents the longitude of point M, and the angle L represents the latitude of point M.

3.载体坐标系(b)：该坐标系原点与载体的质心重合，与地理坐标系的原点位置一致；对于飞机或者巡航载体，其x_b轴沿着载体的横轴向右，y_b轴沿着载体纵轴向前，z_b轴沿着载体竖轴向上，即“右前上”坐标系，如图2所示，其中β_S和β_P分别为载体坐标系下的方位角和俯仰角，图示中β_S为正值，β_P为负值；而分别针对发射机及接收机来说，β_TS和β_TP分别为发射机载体坐标系下的方位角和俯仰角，β_RS和β_RP分别为接收机载体坐标系下的方位角和俯仰角，图示中皆为正值。3. Carrier coordinate system (b): The origin of the coordinate system coincides with the center of mass of the carrier, which is consistent with the origin of the geographic coordinate system; for aircraft or cruise carriers, the x and _b axes are along the horizontal axis of the carrier to the right, and the y and _b axes Moving forward along the longitudinal axis of the carrier, the z _b axis goes up along the vertical axis of the carrier, that is, the "right front upper" coordinate system, as shown in Figure 2, where β _S and β _P are the azimuth and pitch in the carrier coordinate system, respectively In the figure, β _S is a positive value, and β _P is a negative value; and for the transmitter and receiver, β _TS and β _TP are the azimuth and elevation angles in the carrier coordinate system of the transmitter, respectively, and β _RS and β _RP are the azimuth and elevation angles in the receiver carrier coordinate system, respectively, and they are all positive values in the illustration.

4.载体姿态角(ψ,θ,γ)：4. Carrier attitude angle (ψ, θ, γ):

①航向角(ψ)：定义载体(飞机或者巡航飞行器)绕垂线方向转动，载体的纵轴在水平面上的投影与地理北向之间的夹角为航向角，数值以地理北向为起点，顺时针方向为正，其定义域为0°～360°。①Course angle (ψ): It defines the rotation of the carrier (aircraft or cruise aircraft) around the vertical direction. The angle between the projection of the longitudinal axis of the carrier on the horizontal plane and the geographic north is the heading angle. The clockwise direction is positive, and its definition range is 0°～360°.

②俯仰角(θ)：定义载体绕横向水平轴转动产生的纵轴与纵向水平轴的夹角为俯仰角，俯仰角以水平轴为起点，向上为正，向下为负，定义域-90°～90°。② Pitch angle (θ): Define the angle between the vertical axis and the longitudinal horizontal axis generated by the rotation of the carrier around the horizontal horizontal axis. °～90°.

③ 横滚角(γ)：定义载体绕纵轴、相对于铅垂平面的转角为横滚角，从铅垂平面算起，右倾为正，左倾为负，定义域为-180°～180°；如图3所示即为姿态角的定义示意图。③ Roll angle (γ): Define the roll angle of the carrier around the longitudinal axis and relative to the vertical plane. Calculated from the vertical plane, the right tilt is positive, and the left tilt is negative. The definition range is -180°～180° ; As shown in Figure 3, it is a schematic diagram of the definition of the attitude angle.

5.航姿仪：航姿仪是安置在载体(飞机或者巡航飞行器)上的一种导航设备，其为飞行体提供多项信息，其中在空间同步系统中需要用到的信息包括：载体位置信息(经度、纬度和高度)和载体姿态信息(航向角、俯仰角和横滚角)。5. Heading and attitude instrument: the heading and attitude instrument is a navigation device placed on the carrier (aircraft or cruise aircraft), which provides multiple information for the flying object, and the information that needs to be used in the space synchronization system includes: the position of the carrier Information (longitude, latitude and altitude) and carrier attitude information (course angle, pitch angle and roll angle).

6.天线伺服系统：天线伺服系统是安置在载体上的一种控制天线指向的设备，其包括数字信号处理模块和伺服电机两个模块。其中，数字信号处理模块接收两种信息：俯仰角和方位角；当数字信号处理模块获取到这两种信息之后，其通过一定运算控制伺服电机，以使天线指向设定的方向。6. Antenna servo system: The antenna servo system is a device placed on the carrier to control the antenna pointing, which includes two modules: a digital signal processing module and a servo motor. Among them, the digital signal processing module receives two kinds of information: pitch angle and azimuth angle; after the digital signal processing module obtains these two kinds of information, it controls the servo motor through a certain calculation so that the antenna points to the set direction.

本发明的解决方案是在确定天线指向拟成像区域之前对发、收射机(平台)的参数进行初始化处理，其中发射机的初始化参数包括：[λ_T L_T H_T]，分别对应发射机的经度、纬度和高度，[ψ_T θ_T γ_T]分别对应发射机的航向角、俯仰角和横滚角；接收机的初始化参数包括：[λ_R L_R H_R]，分别对应接收机的经度、纬度和高度，[ψ_R θ_R γ_R]分别对应接收机的航向角、俯仰角和横滚角；初始化完成之后：发射机再完成对其天线指向拟成像目标区域中心的控制及其相关的处理方法(算法)，而接收机则根据发射机传来的目标区域的参数完成对其接收天线指向的控制、使接收机天线指向与发射机天线指向一致；从而不需拟成像的点目标准确的坐标位置参数即可完成接收机天线与发射机天线指向的空间同步。因而本发明双基地合成孔径雷达的空间同步方法包括：The solution of the present invention is to initialize the parameters of the transmitter and receiver (platform) before determining that the antenna points to the intended imaging area, wherein the initialization parameters of the transmitter include: [λ _T L _T H _T ], respectively corresponding to the transmitter Longitude, latitude and altitude, [ψ _T θ _T γ _T ] correspond to the heading angle, pitch angle and roll angle of the transmitter respectively; the initialization parameters of the receiver include: [λ _R L _R H _R ], corresponding to the receiver longitude, latitude and altitude, [ψ _R θ _R γ _R ] correspond to the heading angle, pitch angle and roll angle of the receiver respectively; Its related processing method (algorithm), and the receiver completes the control of its receiving antenna pointing according to the parameters of the target area transmitted from the transmitter, so that the receiver antenna pointing is consistent with the transmitter antenna pointing; The accurate coordinate position parameters of the point target can complete the spatial synchronization of the receiver antenna and the transmitter antenna pointing. Thereby the spatial synchronization method of bistatic synthetic aperture radar of the present invention comprises:

初始化处理：首先对发射机、接收机平台参数分别进行相应的初始化处理，其中：发射机初始化参数包括：发射机本身的经度[λ_T]、纬度[L_T]、高度[H_T]，航向角[ψ_T]、俯仰角[θ_T]及横滚角[γ_T]；接收机的初始化参数包括：接收机本身的经度[λ_R]、纬度[L_R]、高度[H_R]、航向角[ψ_R]、俯仰角[θ_R]及横滚角[γ_R]；此后发射机A与接收机B分别按以下步骤进行：Initialization processing: firstly, corresponding initialization processing is performed on the transmitter and receiver platform parameters, among which: the transmitter initialization parameters include: longitude [λ _T ], latitude [L _T ], altitude [H _T ], heading of the transmitter itself angle [ψ _T ], pitch angle [θ _T ] and roll angle [γ _T ]; receiver initialization parameters include: longitude [λ _R ], latitude [L _R ], height [H _R ], Heading angle [ψ _R ], pitch angle [θ _R ] and roll angle [γ _R ]; after that, transmitter A and receiver B follow the steps below:

发射机A：Transmitter A:

步骤A₁.确定天线指向的单位方向向量向发射机天线伺服系统输入发射机载体坐标系下天线指向中的方位角β_TS及俯仰角β_TP参数，并确定该天线指向参数在发射机载体坐标系下的单位方向向量 Step A _1. Determine the unit direction vector the antenna is pointing at Input the azimuth β _TS and pitch angle β _TP parameters of the antenna pointing in the transmitter carrier coordinate system to the transmitter antenna servo system, and determine the unit direction vector of the antenna pointing parameters in the transmitter carrier coordinate system

步骤A₂.载体坐标系与地理坐标系向量的转换：将发射机载体坐标系下的单位方向向量通过转换矩阵转换成发射机地理坐标系下的向量 Step A _2. Transformation of carrier coordinate system and geographic coordinate system vector: the unit direction vector under the transmitter carrier coordinate system By transformation matrix Convert to a vector in the geographic coordinate system of the transmitter

步骤A₃.确定发射机到目标区域中心的向量：根据发射机到地面的垂直高度并通过步骤A₂所得发射机地理坐标系下的向量确定地理坐标系下发射机到目标区域中心的向量 Step A3. Determine the vector from the transmitter to the center _of the target area: according to the vertical height from the transmitter to the ground and through the vector under the geographic coordinate system of the transmitter obtained in step _A2 Determine the vector from the transmitter to the center of the target area in the geographic coordinate system

步骤A₄.地理坐标系与地球坐标系的转换：将地理坐标系下的向量通过转换矩阵转换成地球坐标系下的向量 Step A _4. Transformation between the geographic coordinate system and the earth coordinate system: the vector under the geographic coordinate system By transformation matrix Convert to a vector in the earth coordinate system

步骤A₅.确定发射机在地球坐标系下的向量根据发射机的经度、纬度和高度参数，确定发射机在地球坐标系下的向量 Step _A5 . Determine the vector of the transmitter in the earth coordinate system According to the longitude, latitude and altitude parameters of the transmitter, determine the vector of the transmitter in the earth coordinate system

步骤A₆.确定目标区域中心的位置向量根据向量和向量确定地球坐标系下目标区域中心的位置向量然后经过数据传输通道，将该位置向量发送给接收机；Step _A6 . Determine the location vector of the center of the target area According to the vector and vector Determine the position vector of the center of the target area in the earth coordinate system Then through the data transmission channel, the position vector sent to the receiver;

接收机B：Receiver B:

步骤B₁.确定接收机在地球坐标系位置向量根据接收机初始化参数，将其中的经度、纬度和高度参数转换成地球坐标系下的位置向量 Step _B1 . Determine the receiver position vector in the earth coordinate system According to the initialization parameters of the receiver, convert the longitude, latitude and altitude parameters into the position vector in the earth coordinate system

步骤B₂.确定接收机指向目标区域中心指向向量根据收到的由发射机步骤A₆发送的目标区域中心位置向量和接收机在地球坐标系位置向量确定地球坐标系下接收机指向目标区域中心的指向向量 Step _B2 . Determine the receiver pointing vector towards the center of the target area According to the received target area center position vector sent by the transmitter step A ₆ and the receiver position vector in the earth coordinate system Determine the pointing vector of the receiver pointing to the center of the target area in the earth coordinate system

步骤B₃.确定地理坐标系下的指向向量根据地球坐标系到接收机地理坐标系的转换矩阵将步骤B₂所得指向向量转换成接收机地理坐标系下的指向向量 Step _B3 . Determine the pointing vector in the geographic coordinate system Conversion matrix from the earth coordinate system to the receiver geographic coordinate system Point to the vector obtained in step B ₂ Converted to a pointing vector in the receiver's geographic coordinate system

步骤B₄.确定载体坐标系下的指向向量根据接收机地理坐标系到接收机载体坐标系的转换矩阵将地理坐标系下的指向向量转换成接收机载体坐标系下的指向向量 Step B4 _. Determine the pointing vector in the carrier coordinate system Transformation matrix from receiver geographic coordinate system to receiver carrier coordinate system The pointing vector in the geographic coordinate system Converted to the pointing vector in the receiver carrier coordinate system

步骤B₅.完成接收机天线与发射机天线指向的空间同步：根据步骤B₄所得指向向量确定接收机载体坐标系下接收机天线指向的方位角β_RS和俯仰角β_RP，再将该方位角β_RS和俯仰角β_RP输入接收机天线伺服系统并完成接收机天线与发射机天线指向一致的空间同步。Step _B5 . Complete the spatial synchronization of the pointing of the receiver antenna and the transmitter antenna: according to the pointing vector obtained in step _B4 Determine the azimuth β _RS and elevation angle β _RP of the receiver antenna pointing in the receiver carrier coordinate system, and then input the azimuth β _RS and elevation angle β _RP into the receiver antenna servo system to complete the receiver antenna and transmitter antenna pointing Consistent space synchronization.

在步骤A₂中所述转换矩阵为：The transformation matrix described in step A ₂ for:

${C C}_{b b}^{g g} = = [\begin{matrix} cos cos {γ γ}_{T T} cos cos {ψ ψ}_{T T} + + sin sin {γ γ}_{T T} sin sin {θ θ}_{T T} sin sin {ψ ψ}_{T T} & cos cos {θ θ}_{T T} sin sin {ψ ψ}_{T T} & sin sin {γ γ}_{T T} cos cos {ψ ψ}_{T T} - - cos cos {γ γ}_{T T} sin sin {θ θ}_{T T} sin sin {ψ ψ}_{T T} \\ - - cos cos {γ γ}_{T T} sin sin {ψ ψ}_{T T} + + sin sin {γ γ}_{T T} sin sin {θ θ}_{T T} cos cos {ψ ψ}_{T T} & cos cos {θ θ}_{T T} cos cos {ψ ψ}_{T T} & - - sin sin {γ γ}_{T T} cos cos {ψ ψ}_{T T} - - cos cos {γ γ}_{T T} sin sin {θ θ}_{T T} cos cos {ψ ψ}_{T T} \\ - - sin sin {γ γ}_{T T} cos cos {θ θ}_{T T} & {sin sin θ θ}_{T T} & cos cos {γ γ}_{T T} cos cos {θ θ}_{T T} \end{matrix}]$

式中：ψ_T、θ_T、γ_T分别为发射机的航向角、俯仰角和横滚角。In the formula: ψ _T , θ _T , γ _T are the heading angle, pitch angle and roll angle of the transmitter, respectively.

步骤A₄中所述转换矩阵为：The transformation matrix described in Step A ₄ for:

${C C}_{g g}^{e e} = = [\begin{matrix} - - {sin sin λ λ}_{T T} & - - sin sin {L L}_{T T} cos cos {λ λ}_{T T} & cos cos {L L}_{T T} cos cos {λ λ}_{T T} \\ cos cos {λ λ}_{T T} & - - sin sin {L L}_{T T} sin sin {λ λ}_{T T} & cos cos {L L}_{T T} sin sin {λ λ}_{T T} \\ 00 & cos cos {L L}_{T T} & sin sin {L L}_{T T} \end{matrix}]$

其中：λ_T和L_T分别表示发射机所在位置的经度和纬度。Among them: λ _T and L _T represent the longitude and latitude of the location of the transmitter, respectively.

在步骤A₅中所述根据发射机的经度、纬度和高度参数，确定发射机在地球坐标系下的向量为：According to the longitude, latitude and height parameters of the transmitter described in step _A5 , determine the vector of the transmitter under the earth coordinate system for:

$\overset{&RightArrow; &Right Arrow;}{A A 55} = = {[\begin{matrix} {A A}_{5151} & {A A}_{5252} & {A A}_{5353} \end{matrix}]}^{T T}$

$= = {[\begin{matrix} (({H h}_{T T} + + {R R}_{NT NT})) cos cos {L L}_{T T} cos cos {λ λ}_{T T} & (({H h}_{T T} + + {R R}_{NT NT})) cos cos {L L}_{T T} sin sin {λ λ}_{T T} & [[{R R}_{NT NT} {((11 - - f f))}^{22} + + {H h}_{T T}]] sin sin \end{matrix} {L L}_{T T}]}^{T T}$

其中： $\{\begin{matrix} f = \frac{R_{e} - R_{p}}{R_{e}} \\ R_{NT} \approx R_{e} (1 + f \sin^{2} L_{T}) \end{matrix}$ in: $\{\begin{matrix} f = \frac{R_{e} - R_{p}}{R_{e}} \\ R_{NT} \approx R_{e} (1 + f \sin^{2} L_{T}) \end{matrix}$

上述式中：λ_T、L_T、H_T分别为发射机的经度、纬度和海拔高度，R_NT为地面上发射机所在位置的卯酉圈曲率半径，f为地球椭球的椭圆度，R_e＝6378136m为赤道平面半径(长半径)，R_p＝6356755m为极轴半径(短半径)。In the above formula: λ _T , L _T , H _T are the longitude, latitude and altitude of the transmitter respectively, R _NT is the radius of curvature of the unitary circle where the transmitter is located on the ground, f is the ellipticity of the earth ellipsoid, R _e = 6378136m is the equatorial plane radius (major radius), and R _p = 6356755m is the polar axis radius (short radius).

在步骤A₆中所述获取地球坐标系下目标区域中心的位置向量其向量为：Obtain the position vector of the center of the target area under the earth coordinate system as described in step _A6 Its vector is:

$\overset{&RightArrow; &Right Arrow;}{A A 66} = = {[\begin{matrix} {A A}_{6161} & {A A}_{6262} & {A A}_{6363} \end{matrix}]}^{T T} = = \overset{&RightArrow; &Right Arrow;}{A A 44} + + \overset{&RightArrow; &Right Arrow;}{A A 55} = = {[\begin{matrix} {A A}_{4141} + + {A A}_{5151} & {A A}_{4242} + + {A A}_{5252} & {A A}_{4343} + + {A A}_{5353} \end{matrix}]}^{T T} . .$

步骤B₁中所述将接收机初始化参数中的经度、纬度和高度参数转换成地球坐标系下的位置向量其位置向量为：Convert the longitude, latitude and height parameters in the receiver initialization parameters into the position vector under the earth coordinate system described in step _B1 its position vector for:

$\overset{&RightArrow; &Right Arrow;}{B B 11} = = {[\begin{matrix} {B B}_{1111} & {B B}_{1212} & {B B}_{1313} \end{matrix}]}^{T T}$

$= = {[\begin{matrix} (({H h}_{R R} + + {R R}_{NR NR})) cos cos {L L}_{R R} cos cos {λ λ}_{R R} & (({H h}_{R R} + + {R R}_{NR NR})) cos cos {L L}_{R R} sin sin {λ λ}_{R R} & [[{R R}_{NR NR} {((11 - - f f))}^{22} + + {H h}_{R R}]] sin sin \end{matrix} {L L}_{R R}]}^{T T}$

其中：R_NR≈R_e(1+f sin² L_R)为地面上接收机所在位置的卯酉圈曲率半径，λ_R、L_R、H_R分别为接收机的经度、纬度和海拔高度，f为地球椭球的椭圆度，R_e为赤道平面半径(长半径)，R_p为极轴半径(短半径)。Among them: R _NR ≈ R _e (1+f sin ² L _R ) is the radius of curvature of the unitary circle where the receiver is located on the ground, λ _R , L _R , _HR are the longitude, latitude and altitude of the receiver respectively, f is the ellipticity of the earth ellipsoid, _Re is the equatorial plane radius (long radius), and R _p is the polar axis radius (short radius).

步骤B₃中所述根据地球坐标系到接收机地理坐标系的转换矩阵将步骤B₂所得指向向量转换成接收机地理坐标系下的指向向量其中转换矩阵为：According to the transformation matrix of the earth coordinate system to the receiver geographic coordinate system described in step _B3 Point to the vector obtained in step B ₂ Converted to a pointing vector in the receiver's geographic coordinate system where the transformation matrix for:

${C C}_{e e}^{g g} = = [\begin{matrix} - - sin sin {λ λ}_{R R} & cos cos {λ λ}_{R R} & 00 \\ - - sin sin {L L}_{R R} cos cos {λ λ}_{R R} & - - sin sin {L L}_{R R} sin sin {λ λ}_{R R} & cos cos {L L}_{R R} \\ cos cos {L L}_{R R} cos cos {λ λ}_{R R} & cos cos {L L}_{R R} sin sin {λ λ}_{R R} & sin sin {L L}_{R R} \end{matrix}]$

则接收机地理坐标系下的指向向量 Then the pointing vector in the receiver geographic coordinate system

步骤B₄中所述接收机地理坐标系到接收机载体坐标系的转换矩阵将地理坐标系下的指向向量转换成接收机载体坐标系下的指向向量其转换矩阵为： _The conversion matrix of the receiver geographic coordinate system to the receiver carrier coordinate system described in step B4 The pointing vector in the geographic coordinate system Converted to the pointing vector in the receiver carrier coordinate system its transformation matrix for:

${C C}_{g g}^{b b} = = [\begin{matrix} cos cos {γ γ}_{R R} cos cos {ψ ψ}_{R R} + + sin sin {γ γ}_{R R} sin sin {θ θ}_{R R} sin sin {ψ ψ}_{R R} & - - cos cos {γ γ}_{R R} sin sin {ψ ψ}_{R R} + + sin sin {γ γ}_{R R} sin sin {θ θ}_{R R} cos cos {ψ ψ}_{R R} & - - sin sin {γ γ}_{R R} cos cos {θ θ}_{R R} \\ cos cos {θ θ}_{R R} sin sin {ψ ψ}_{R R} & cos cos {θ θ}_{R R} cos cos {ψ ψ}_{R R} & sin sin {θ θ}_{R R} \\ sin sin {γ γ}_{R R} cos cos {ψ ψ}_{R R} - - cos cos {γ γ}_{R R} sin sin {θ θ}_{R R} sin sin {ψ ψ}_{R R} & - - {sin sin γ γ}_{R R} cos cos {ψ ψ}_{R R} - - cos cos {γ γ}_{R R} sin sin {θ θ}_{R R} cos cos {ψ ψ}_{R R} & cos cos {γ γ}_{R R} cos cos {θ θ}_{R R} \end{matrix}]$

其中：ψ_R、θ_R、^γ _R分别为接收机的航向角、俯仰角和横滚角；Among them: ψ _R , θ _R , ^γ _R are the heading angle, pitch angle and roll angle of the receiver respectively;

则接收机载体坐标系下的向量为： $\overset{&RightArrow;}{B 4} = {[\begin{matrix} B_{41} & B_{42} & B_{43} \end{matrix}]}^{T} = C_{g}^{b} \times \overset{&RightArrow;}{B 3} .$ Then the vector in the receiver carrier coordinate system for: $\overset{&Right Arrow;}{B 4} = {[\begin{matrix} B_{41} & B_{42} & B_{43} \end{matrix}]}^{T} = C_{g}^{b} \times \overset{&Right Arrow;}{B 3} .$

本发明发射机不需预先知道目标区域中心点的WGS-84坐标、即不采用目标区域中心点的WGS-84坐标，而是采用一种基于发射机天线指向拟成像(定位)目标区域的空间同步方法；亦即发射机只需控制天线指向，使天线指向某一目标区域的中心，接收机将会自动跟进，使接收机天线指向与发射机天线指向一致，而且发射机与接收机采用不同的坐标转换方法(算法)、在进行坐标转换中不需知道拟成像目标点准确的位置坐标参数，即可完成接收机天线与发射机天线指向的空间同步；从而具有可有效提高了双基地SAR空间同步的效率，精确度较高，飞行模式灵活，有利于广泛应用等特点。克服了背景技术存在的对目标的位置坐标要求准确、坐标转换(算法)中必须输入目标点的WGS-84，而存在的飞行模式的灵活性差、难以在实际中得到有效应用等缺陷。The transmitter of the present invention does not need to know the WGS-84 coordinates of the center point of the target area in advance, that is, it does not use the WGS-84 coordinates of the center point of the target area, but adopts a space based on the transmitter antenna pointing to the intended imaging (positioning) target area Synchronization method; that is, the transmitter only needs to control the antenna pointing so that the antenna points to the center of a certain target area, and the receiver will automatically follow up so that the receiver antenna pointing is consistent with the transmitter antenna pointing, and the transmitter and receiver adopt Different coordinate conversion methods (algorithms), without knowing the exact position coordinate parameters of the intended imaging target point during coordinate conversion, can complete the spatial synchronization of the receiver antenna and transmitter antenna pointing; thus effectively improving the bistatic The efficiency of SAR space synchronization is high, the accuracy is high, the flight mode is flexible, and it is conducive to wide application. It overcomes the defects in the background technology that the target position coordinates must be accurate, the WGS-84 of the target point must be input in the coordinate conversion (algorithm), and the flight mode has poor flexibility and is difficult to be effectively applied in practice.

附图说明：Description of drawings:

图1为地球坐标系与地理坐标系示意图；Fig. 1 is the schematic diagram of earth coordinate system and geographic coordinate system;

图2为载体坐标系及天线指向示意图；Fig. 2 is a schematic diagram of carrier coordinate system and antenna pointing;

图3为载体姿态角的定义示意图，图中的俯仰角、横滚角和航向角均为正值；Figure 3 is a schematic diagram of the definition of the attitude angle of the carrier, and the pitch angle, roll angle and heading angle in the figure are all positive values;

图4为双基地SAR空间同步状态示意图；Fig. 4 is a schematic diagram of a bistatic SAR space synchronization state;

图5为收、发载机波束中心在地面的偏移差的1000次蒙特卡洛仿真结果图(坐标图)。Fig. 5 is the 1000 times Monte Carlo simulation result diagram (coordinate diagram) of the offset difference between the receiver and the transmitter beam center on the ground.

具体实施方式：detailed description:

初始化处理：其中发射机的初始化参数为：方位角和俯仰角(β_TS，β_TP)＝(41.04°，-88.27°)；经度、纬度和海拔高度(λ_T，L_T，H_T )＝(104°，30°，5111m)；航向角、俯仰角和横滚角(ψ_T，θ_T，γ_T)＝(90°，0°，0°)；发射机正投影下对应地面海拔高度H_g＝250m。接收机的初始化参数为：经度、纬度和海拔高度(λ_R，L_R，H_R)＝(104°，30°，4361m)；航向角、俯仰角和横滚角(ψ_R，θ_R，γ_R)＝(90°，0°，0°)；接收机正投影下对应地面海拔高度H_g＝250m；此后发射机A与接收机B分别按以下步骤进行：Initialization process: where the initialization parameters of the transmitter are: azimuth and elevation angle (β _TS , β _TP ) = (41.04°, -88.27°); longitude, latitude and altitude (λ _T , L _T , H _T ) = (104°, 30°, 5111m); heading angle, pitch angle and roll angle (ψ _T , θ _T , γ _T ) = (90°, 0°, 0°); the altitude corresponding to the ground under the orthographic projection of the transmitter _Hg = 250m. The initialization parameters of the receiver are: longitude, latitude and altitude (λ _R , L _R , H _R ) = (104°, 30°, 4361m); heading angle, pitch angle and roll angle (ψ _R , θ _R , γ _R )=(90°, 0°, 0°); under the orthographic projection of the receiver, the corresponding ground altitude H _g =250m; after that, transmitter A and receiver B respectively follow the steps below:

发射机A：Transmitter A:

步骤A₁.确定天线指向的单位方向向量向天线伺服系统输入天线指向(角度)参数(β_TS，β_TP)，完成发射机在这一方向的天线波束对准；如图2所示，发射机天线将指向其载体坐标系下方向为(β_TS，β_TP)的某一区域中心，这一方向在载体坐标系下的单位方向向量为： $\overset{&RightArrow;}{A 1} = {[\cos β_{TP} \cos β_{TS}, \cos β_{TP} \sin β_{TS}, - \sin β_{TP}]}^{T};$ Step A _1. Determine the unit direction vector the antenna is pointing at Input the antenna pointing (angle) parameters (β _TS , β _TP ) to the antenna servo system to complete the antenna beam alignment of the transmitter in this direction; as shown in Figure 2, the transmitter antenna will point to the direction of the carrier coordinate system as (β _TS , β _TP ), the unit direction vector of this direction in the carrier coordinate system is: $\overset{&Right Arrow;}{A 1} = {[\cos β_{TP} \cos β_{TS}, \cos β_{TP} \sin β_{TS}, - \sin β_{TP}]}^{T};$

步骤A₂.载体坐标系与地理坐标系向量的转换：将发射机载体坐标系下的单位方向向量转换成发射机地理坐标系下的向量转换矩阵为：Step A _2. Transformation of carrier coordinate system and geographic coordinate system vector: the unit direction vector under the transmitter carrier coordinate system Convert to a vector in the geographic coordinate system of the transmitter The transformation matrix is:

其中：ψ_T、θ_T、γ_T分别为发射机的航向角、俯仰角和横滚角，则发射机地理坐标系下的向量可以表示为：Where: ψ _T , θ _T , and γ _T are the heading angle, pitch angle, and roll angle of the transmitter respectively, and the vector in the geographic coordinate system of the transmitter It can be expressed as:

$\overset{&RightArrow; &Right Arrow;}{A A 22} = = {[\begin{matrix} {A A}_{21 twenty one} & {A A}_{22 twenty two} & {A A}_{23 twenty three} \end{matrix}]}^{T T} = = {C C}_{b b}^{g g} \times \times \overset{&RightArrow; &Right Arrow;}{A A 11}$

步骤A₃.确定发射机到目标区域中心点的向量：根据发射机到地面的垂直高度并通过步骤A₂所得发射机地理坐标系下的向量确定发射机到目标区域中心的向量即：Step A3. Determine the vector from the transmitter to the center point _of the target area: according to the vertical height from the transmitter to the ground and through the vector under the geographic coordinate system of the transmitter obtained in step _A2 Determine the vector from the transmitter to the center of the target area which is:

$\overset{&RightArrow; &Right Arrow;}{A A 33} = = {[\begin{matrix} {A A}_{3131} & {A A}_{3232} & {A A}_{3333} \end{matrix}]}^{T T} = = {H h}_{11} \times \times {[\begin{matrix} 11 & \frac{{A A}_{22 twenty two}}{{A A}_{21 twenty one}} & \frac{{A A}_{23 twenty three}}{{A A}_{21 twenty one}} \end{matrix}]}^{T T}$

其中：发射机正投影下对应地面的海拔高度为H_g＝250m，从发射机航姿仪上所获取发射机的海拔高度为H_T＝5111m，则发射机到地面的垂直高度为：Among them: the altitude corresponding to the ground under the forward projection of the transmitter is H _g = 250m, and the altitude of the transmitter obtained from the attitude indicator of the transmitter is H _T = 5111m, then the vertical height from the transmitter to the ground is:

H₁＝H_T-H_g＝4861mH ₁ =H _T -H _g =4861m

步骤A₄.地理坐标系与地球坐标系向量的转换：将向量转换成地球坐标系下的向量转换矩阵为：Step A _4. Transformation of the geographic coordinate system and the earth coordinate system vector: the vector Convert to a vector in the earth coordinate system transformation matrix for:

其中，λ_T和L_T分别表示发射机所在位置的经度和纬度；那么，向量可以表示为：Among them, λ _T and L _T denote the longitude and latitude of the location of the transmitter respectively; then, the vector It can be expressed as:

$\overset{&RightArrow; &Right Arrow;}{A A 44} = = {[\begin{matrix} {A A}_{4141} & {A A}_{4242} & {A A}_{4343} \end{matrix}]}^{T T} = = {C C}_{g g}^{e e} \times \times \overset{&RightArrow; &Right Arrow;}{A A 33};;$

步骤A₅.确定发射机在地球坐标系下的向量这一步骤仍需要利用航姿仪上获取的发射机经度、纬度和高度信息，其表示为[λ_T L_T H_T]，那么为：Step _A5 . Determine the vector of the transmitter in the earth coordinate system This step still needs to use the longitude, latitude and height information of the transmitter obtained from the attitude instrument, which is expressed as [λ _T L _T H _T ], then for:

上述式中：H_T为发射机的海拔高度、R_NT为地面上发射机所在位置的卯酉圈曲率半径，R_e＝6378136m为赤道平面半径(长半径)，R_p＝6356755m为极轴半径(短半径)；In the above formula: H _T is the altitude of the transmitter, R _NT is the curvature radius of the unitary circle where the transmitter is located on the ground, R _e = 6378136m is the equatorial plane radius (major radius), R _p = 6356755m is the polar axis radius (short radius);

步骤A₆.地球坐标系下目标位置向量为：Step A _6. The target position vector in the earth coordinate system for:

$\overset{&RightArrow; &Right Arrow;}{A A 66} = = {[\begin{matrix} {A A}_{6161} & {A A}_{6262} & {A A}_{6363} \end{matrix}]}^{T T} = = \overset{&RightArrow; &Right Arrow;}{A A 44} + + \overset{&RightArrow; &Right Arrow;}{A A 55}$

$= = {[\begin{matrix} {A A}_{4141} + + {A A}_{5151} & {A A}_{4242} + + {A A}_{5252} & {A A}_{4343} + + {A A}_{5353} \end{matrix}]}^{T T}$

通过运算可得 $\overset{&RightArrow;}{A 6} = {[\begin{matrix} - 1337565.935 & 5364285.097 & 3170406.385 \end{matrix}]}^{T};$ 并将该目标位置向量通过数传通道传递给接收机；can be obtained by operation $\overset{&Right Arrow;}{A 6} = {[\begin{matrix} - 1337565.935 & 5364285.097 & 3170406.385 \end{matrix}]}^{T};$ and put the target position vector Passed to the receiver through the digital transmission channel;

接收机B：Receiver B:

步骤B₁.确定接收机在地球坐标系位置向量根据接收机的初始化参数，将接收机的的经度、纬度和高度参数转换成地球坐标系下的位置向量其位置向量为：Step _B1 . Determine the receiver position vector in the earth coordinate system According to the initialization parameters of the receiver, the longitude, latitude and altitude parameters of the receiver are converted into a position vector in the earth coordinate system its position vector for:

其中：R_NR≈R_e(1+f sin²L_R)为地面上接收机所在位置的卯酉圈曲率半径，f为地球椭球的椭圆度，R_e为赤道平面半径(长半径)，R_p为极轴半径(短半径)；Among them: R _NR ≈ _Re (1+f sin ² L _R ) is the radius of curvature of the unitary circle where the receiver is located on the ground, f is the ellipticity of the earth ellipsoid, _Re is the radius of the equatorial plane (major radius), R _p is the polar axis radius (short radius);

步骤B₂.确定接收机指向目标区域中心指向向量根据收到的由发射机步骤A₆发送的目标区域中心位置向量和接收机在地球坐标系位置向量确定地球坐标系下接收机指向目标区域中心的指向向量其指向向量为：Step _B2 . Determine the receiver pointing vector towards the center of the target area According to the received target area center position vector sent by the transmitter step A ₆ and the receiver position vector in the earth coordinate system Determine the pointing vector of the receiver pointing to the center of the target area in the earth coordinate system its pointing vector for:

$\overset{&RightArrow; &Right Arrow;}{B B 22} = = {[\begin{matrix} {B B}_{21 twenty one} & {B B}_{22 twenty two} & {B B}_{3333} \end{matrix}]}^{T T} = = \overset{&RightArrow; &Right Arrow;}{A A 66} - - \overset{&RightArrow; &Right Arrow;}{B B 11} = = {[\begin{matrix} {A A}_{6161} - - {B B}_{1111} & {A A}_{6262} - - {B B}_{1212} & {A A}_{6363} - - {B B}_{1313} \end{matrix}]}^{T T};;$

步骤B₃.确定地理坐标系下的指向向量根据地球坐标系到接收机地理坐标系的转换矩阵将步骤B₂所得指向向量转换成接收机地理坐标系下的指向向量其转换矩阵为：Step _B3 . Determine the pointing vector in the geographic coordinate system Conversion matrix from the earth coordinate system to the receiver geographic coordinate system Point to the vector obtained in step B ₂ Converted to a pointing vector in the receiver's geographic coordinate system its transformation matrix for:

则接收机地理坐标系下的指向向量为：Then the pointing vector in the receiver geographic coordinate system for:

$\overset{&RightArrow; &Right Arrow;}{B B 33} = = {[\begin{matrix} {B B}_{3131} & {B B}_{3232} & {B B}_{3333} \end{matrix}]}^{T T} = = {C C}_{e e}^{g g} \times \times \overset{&RightArrow; &Right Arrow;}{B B 22};;$

步骤B₄.确定载体坐标系下的指向向量根据接收机地理坐标系到接收机载体坐标系的转换矩阵将地理坐标系下的指向向量转换成接收机载体坐标系下的指向向量转换矩阵为：Step B4 _. Determine the pointing vector in the carrier coordinate system Transformation matrix from receiver geographic coordinate system to receiver carrier coordinate system The pointing vector in the geographic coordinate system Converted to the pointing vector in the receiver carrier coordinate system transformation matrix for:

其中：ψ_R、θ_R、γ_R分别为接收机的航向角、俯仰角和横滚角，则接收机载体坐标系下的向量为：Where: ψ _R , θ _R , and γ _R are the heading angle, pitch angle, and roll angle of the receiver respectively, and the vector in the carrier coordinate system of the receiver for:

$\overset{&RightArrow; &Right Arrow;}{B B 44} = = {[\begin{matrix} {B B}_{4141} & {B B}_{4242} & {B B}_{4343} \end{matrix}]}^{T T} = = {C C}_{g g}^{b b} \times \times \overset{&RightArrow; &Right Arrow;}{B B 33};;$

步骤B₅.确定接收机天线指向角：根据步骤B₄所得指向向量确定接收机载体坐标系下接收机天线指向的方位角β_RS和俯仰角β_RP为：Step _B5 . Determine the receiver antenna pointing angle: according to the pointing vector obtained in step _B4 Determine the azimuth β _RS and elevation angle β _RP of the receiver antenna pointing in the receiver carrier coordinate system as:

$\{\begin{matrix} {β β}_{RS RS} = = arctan arctan \frac{{B B}_{4242}}{{B B}_{4141}} \\ {β β}_{RP RP} = = arctan arctan \frac{{B B}_{4343}}{\sqrt{{B B}_{4141}^{22} + + {B B}_{4242}^{22}}} \end{matrix}$

通过计算仿真可得(β_RS，β_RP)＝(41.04°，-87.95°)；再将所得方位角β_RS和俯仰角β_RP值输入接收机天线伺服系统，进而完成接收机天线与发射机天线指向一致的空间同步。Through calculation and simulation, (β _RS , β _RP ) = (41.04°, -87.95°); then input the obtained azimuth angle β _RS and elevation angle β _RP into the receiver antenna servo system, and then complete the receiver antenna and transmitter Antennas are pointing in unison with space synchronization.

仿真运行：按照上述步骤进行1000次蒙特卡洛仿真，本发明提供的参数可以计算出发射机、接收机在地面的波束直径分别为：Simulation operation: carry out 1000 Monte Carlo simulations according to the above steps, the parameters provided by the present invention can calculate the beam diameters of transmitter and receiver on the ground as follows:

$\{\begin{matrix} {d d}_{t t} = = \sqrt{{(({R R}_{T T} sin sin {β β}_{TP TP}))}^{22} + + {(({R R}_{T T} cos cos {β β}_{TP TP} cos cos {β β}_{TS TS}))}^{22}} \times \times [[tan the tan (({α α}_{T T} + + \frac{{φ φ}_{T T}}{22})) - - tan the tan (({α α}_{T T} - - \frac{{φ φ}_{T T}}{22}))]] \approx \approx 280.2339 280.2339 m m \\ {d d}_{r r} = = \sqrt{{(({R R}_{R R} sin sin {β β}_{22 twenty two}))}^{22} + + {(({R R}_{R R} cos cos {β β}_{RP RP} cos cos {β β}_{RS RS}))}^{22}} \times \times [[tan the tan (({α α}_{R R} + + \frac{{φ φ}_{R R}}{22})) - - tan the tan (({α α}_{R R} - - \frac{{φ φ}_{R R}}{22}))]] \approx \approx 252.2761 252.2761 m m \\ {α α}_{T T} = = arcsin arcsin [[cos cos {β β}_{TP TP} sin sin {β β}_{TS TS}]] \\ {α α}_{R R} = = arcsin arcsin [[{cos cos β β}_{RP RP} sin sin {β β}_{RS RS}]] \end{matrix}$

其中：φ_T(R)＝3.3°为发射机、接收机的天线波束角宽度(假设方位向和距离向的天线波束角宽度一样),R_T(R)为发射机(接收机)到目标点的距离。假设载体位置误差为[Δλ ΔL ΔH]，其中Δλ和ΔL的区间为(-0.00001°,0.00001°),ΔH的区间为(-1，1)；载体姿态误差[Δψ Δθ Δγ]，其区间为(-0.01°,0.01°)。图5为收发波束中心在地面的偏移差的1000次蒙特卡洛仿真图，可以看出其偏移差在8m范围之内，偏移差远小于发射机、接收机在地面的波束直径，由此可以看出本发明具体实施方式具有较高的精确度。Where: φ _T(R) = 3.3° is the antenna beam angle width of the transmitter and receiver (assuming that the antenna beam angle width in the azimuth direction and the range direction are the same), and R _T(R) is the distance from the transmitter (receiver) to the target point distance. Suppose the carrier position error is [Δλ ΔL ΔH], where the interval of Δλ and ΔL is (-0.00001°, 0.00001°), and the interval of ΔH is (-1, 1); the carrier attitude error [Δψ Δθ Δγ], its interval is (-0.01°,0.01°). Figure 5 is a 1000-times Monte Carlo simulation diagram of the offset difference of the transmit and receive beam center on the ground. It can be seen that the offset difference is within the range of 8m, and the offset difference is much smaller than the beam diameter of the transmitter and receiver on the ground. It can be seen that the specific implementation of the present invention has higher accuracy.

Claims

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} = [\begin{matrix} {cosγ}_{T} {cosψ}_{T} + {sinγ}_{T} {sinθ}_{T} {sinψ}_{T} & {cosθ}_{T} {sinψ}_{T} & {sinγ}_{T} {cosψ}_{T} - {cosγ}_{T} {sinθ}_{T} {sinψ}_{T} \\ - {cosγ}_{T} {sinψ}_{T} + {sinγ}_{T} {sinθ}_{T} {cosψ}_{T} & {cosθ}_{T} {cosψ}_{T} & - {sinγ}_{T} {cosψ}_{T} - {cosγ}_{T} {sinθ}_{T} {cosψ}_{T} \\ - {sinγ}_{T} {cosθ}_{T} & {sinθ}_{T} & {cosγ}_{T} {cosθ}_{T} \end{matrix}]

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} = [\begin{matrix} - {sinλ}_{T} & - {sinL}_{T} {cosλ}_{T} & {cosL}_{T} {cosλ}_{T} \\ {cosλ}_{T} & - {sinL}_{T} {sinλ}_{T} & {cosL}_{T} {sinλ}_{T} \\ 0 & {cosL}_{T} & {sinL}_{T} \end{matrix}]

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{matrix} \overset{&RightArrow;}{A 5} = {[\begin{matrix} A_{51} & A_{52} & A_{53} \end{matrix}]}^{T} \\ = {[\begin{matrix} (H_{T} + R_{N T}) {cosL}_{T} {cosλ}_{T} & (H_{T} + R_{N T}) {cosL}_{T} {cosλ}_{T} & [R_{N T} {(1 - f)}^{2} + H_{T}] {sinL}_{T} \end{matrix}]}^{T} \end{matrix}

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{matrix} \overset{&RightArrow;}{B 1} = {[\begin{matrix} B_{11} & B_{12} & B_{13} \end{matrix}]}^{T} \\ = {[\begin{matrix} (H_{R} + R_{H R}) {cosL}_{R} {cosλ}_{R} & (H_{R} + R_{H R}) {cosL}_{R} {cosλ}_{R} & [R_{N R} {(1 - f)}^{2} + H_{R}] {sinL}_{R} \end{matrix}]}^{T} \end{matrix}

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} = [\begin{matrix} - {sinλ}_{R} & {cosλ}_{R} & 0 \\ - {sinL}_{R} {cosλ}_{R} & - {sinL}_{R} {sinλ}_{R} & {cosL}_{R} \\ {cosL}_{R} {cosλ}_{R} & {cosL}_{R} {sinλ}_{R} & {sinL}_{R} \end{matrix}]

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} = [\begin{matrix} {cosγ}_{R} {cosψ}_{R} + {sinγ}_{R} {sinθ}_{R} {sinψ}_{R} & - {cosγ}_{R} {sinψ}_{R} + {sinγ}_{R} {sinθ}_{R} {cosψ}_{R} & - {sinγ}_{R} {cosθ}_{R} \\ {cosθ}_{R} {sinψ}_{R} & {cosθ}_{R} {cosψ}_{R} & {sinθ}_{R} \\ {sinγ}_{R} {cosψ}_{R} - {cosγ}_{R} {sinθ}_{R} {sinψ}_{R} & - {sinγ}_{R} {cosψ}_{R} - {cosγ}_{R} {sinθ}_{R} {cosψ}_{R} & {cosγ}_{R} {cosθ}_{R} \end{matrix}]

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: