Virtual guidance method based on target position prediction

Abstract

The invention provides a virtual guidance method based on target position prediction. The method comprises the following steps: acquiring longitude and latitude height vectors of a real target through an infrared seeker and an inertial navigation system; estimating a predicted target real-time position vector and a predicted real-time speed vector of the virtual target in the geographic coordinate system; and a predicted line-of-sight angle vector of the virtual target in an aircraft body coordinate system and a predicted line-of-sight angular velocity vector in a body line-of-sight system are calculated through the two, and a guide signal is generated. When the target is shielded by smoke, cloud and mist, the position of the target in the geographical system can be derived through the scheme, and the sight angle under the body coordinate system and the sight angle speed under the body sight system of the aircraft are calculated, so that guidance is realized. Compared with the prior art, the method has the advantages that the moving position of the shielded target is considered, errors are reduced to the maximum extent, and the precision of virtual guidance is improved.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic tracking technology, and in particular to a virtual guidance method based on target position prediction. Background Art

[0002] In the modern military combat system, aircraft play an extremely important role. Aircraft are often equipped with various advanced detection equipment to accurately obtain target information in combat scenarios, among which infrared cameras are a very critical device. The infrared camera carried on the aircraft can take images to determine the position of the target in the image, and the infrared seeker is a device based on the infrared camera to accurately guide the aircraft to track the target.

[0003] However, as the modern battlefield environment becomes more and more complex, interference sources such as smoke and fire are used more and more frequently. This makes the problem that infrared seekers are easily interfered by smoke and fog prominent, and this problem has become the main factor restricting the application of infrared seekers in a wider range. When the target is blocked by smoke and fog, making it impossible for the infrared seeker to track the target, a virtual guidance strategy can be used to solve the virtual line of sight angle and virtual line of sight angular velocity as guidance information.

[0004] At present, most of the commonly used virtual guidance strategies do not consider the movement of the target, or do not use inertial navigation information. They only use the measurement values ​​of the infrared seeker to approximately compensate for some error terms and then extrapolate the line of sight angle and line of sight angular velocity. All of the above methods are relatively simplified methods, and the output guidance information has large errors. Summary of the invention

[0005] In view of the above defects or deficiencies in the prior art, the present application aims to provide a virtual guidance method for target position prediction, comprising the following steps: S100. Obtain the position of the current target in the image, recorded as the real target position; S200. Calculate the latitude and longitude height vector of the target point according to the real target position, and record it as the real target latitude and longitude height vector; S300. Estimate the position and speed of the virtual target in the geographic coordinate system according to the latitude and longitude height vector of the real target, and record them as the predicted target real-time position vector and the predicted real-time speed vector respectively; S400. Calculate the sight angle vector of the virtual target in the aircraft body coordinate system according to the predicted target real-time position vector, and record it as the predicted sight angle vector; S500. Calculate the line of sight angular velocity vector in the stereoscopic line of sight system according to the predicted real-time velocity vector, and record it as the predicted line of sight angular velocity vector.

[0006] According to the technical solution provided in the embodiment of the present application, step S200 includes the following steps: S210. Calculate the sight angle vector of the target relative to the longitudinal axis of the aircraft in the aircraft body coordinate system according to the real target position, recorded as the real sight angle vector, including the real heading sight angle and the real pitch sight angle; S220. Obtain the real-time attitude angle vector of the aircraft relative to the geographic coordinate system; S230. Calculate the sight angle vector of the target in the inertial coordinate system according to the real sight angle vector and the real-time attitude angle vector, and record it as the real inertial system sight angle vector; S240. Obtain the real-time latitude and longitude height vector of the aircraft; S250. Calculate the real target longitude and latitude height vector according to the real-time longitude and latitude height vector of the aircraft and the real inertial system line of sight angle vector.

[0007] According to the technical solution provided in the embodiment of the present application, step S250 includes the following steps: S251. Obtain the distance between the target and the aircraft, recorded as the real distance; S252. Calculate a real latitude and longitude height difference vector according to the real inertial system sight angle vector and the real distance, wherein the real latitude and longitude height difference vector includes a latitude difference between the aircraft and the target, a longitude difference between the aircraft and the target, and a height difference between the aircraft and the target; S253. Calculate the real target longitude and latitude height vector according to the real longitude and latitude height difference vector and the real-time longitude and latitude height vector of the aircraft.

[0008] According to the technical solution provided in the embodiment of the present application, step S230 includes the following steps: S231. Constructing a first transformation matrix according to the real sight line angle vector and the real-time attitude angle vector, wherein the first transformation matrix is ​​a rotation matrix from a stereoscopic sight line coordinate system to a geographic coordinate system; S232. Constructing the first transformation matrix according to the real inertial system sight angle vector and the rotation angle, wherein the rotation angle is the rotation angle of the stereoscopic sight coordinate system relative to the inertial sight system; S233. Calculate the value of the real inertial system line of sight angle vector based on the equivalent relationship.

[0009] According to the technical solution provided in the embodiment of the present application, step S300 includes the following steps: S310. According to the true target latitude and longitude, the predicted real-time position of the target in the north direction and the predicted real-time speed in the north direction are estimated by the Kalman filter algorithm; S320. According to the true target latitude and longitude, the predicted target real-time position and predicted real-time speed in the celestial direction are estimated by the Kalman filter algorithm; S330. According to the true target latitude and longitude, the real-time position of the target in the east direction and the real-time speed in the east direction are estimated by the Kalman filter algorithm; S340. Obtain the predicted target real-time position vector according to the predicted target real-time position in the north direction, the predicted target real-time position in the sky direction, and the predicted target real-time position in the east direction; obtain the predicted real-time speed vector according to the predicted real-time speed in the north direction, the predicted real-time speed in the sky direction, and the predicted real-time speed in the east direction.

[0010] According to the technical solution provided in the embodiment of the present application, step S400 includes the following steps: S410. Obtain the real-time latitude and longitude height vector and the real-time attitude angle vector of the aircraft; S420. Calculate the predicted longitude and latitude height difference vector according to the predicted target real-time position vector and the real-time longitude and latitude height vector of the aircraft; S430. Calculate the sight angle vector of the virtual target in the inertial coordinate system according to the predicted latitude and longitude height difference vector, and record it as the sight angle vector of the virtual target inertial system; S440. Calculate the predicted sight angle vector based on the virtual target inertial system sight angle vector and the real-time attitude angle vector.

[0011] According to the technical solution provided in the embodiment of the present application, step S440 includes the following steps: S441. Constructing the first transformation matrix according to the predicted sight angle vector and the real-time posture angle vector; S442. construct the first transformation matrix according to the virtual target inertial system sight angle vector and the rotation angle; S443. Calculate the value of the predicted sight angle vector based on the equivalent relationship.

[0012] According to the technical solution provided in the embodiment of the present application, step S500 includes the following steps: S510. Obtain the real-time velocity vector of the aircraft in the geographic coordinate system, recorded as the real-time velocity vector of the aircraft; S520. Calculate the line-of-sight angular velocity vector in the inertial line-of-sight system according to the real-time velocity vector of the aircraft and the predicted real-time velocity vector, and record it as the predicted inertial line-of-sight angular velocity vector; S530. Convert the predicted inertial system line of sight angular velocity vector into the predicted line of sight angular velocity vector.

[0013] According to the technical solution provided in the embodiment of the present application, step S520 includes the following steps: S521. Obtaining a coordinate rotation matrix from the geographic coordinate system to the inertial line of sight system, recorded as a second transformation matrix; S522. Obtain the relative speed between the aircraft and the virtual target in the inertial line of sight system according to the second conversion matrix, the predicted real-time speed vector and the aircraft real-time speed vector; S523. Obtain the predicted inertial system line-of-sight angular velocity vector according to the relative velocity calculation.

[0014] According to the technical solution provided in the embodiment of the present application, step S530 includes the following steps: S531. Obtain the coordinate rotation matrix from the inertial line of sight system to the stereoscopic line of sight system, recorded as the third transformation matrix; S532. Calculate the predicted line of sight angular velocity vector based on the third transformation matrix and the predicted inertial system line of sight angular velocity vector.

[0015] In summary, the present application proposes a virtual guidance method based on target position prediction, which obtains the latitude and longitude height vector of the real target through an infrared seeker and an inertial navigation system; estimates the predicted target real-time position vector and predicted real-time velocity vector of the virtual target in the geographic coordinate system; and then calculates the predicted line of sight angle vector of the virtual target in the aircraft body coordinate system and the predicted line of sight angular velocity vector in the stereoscopic line of sight system through the two, and generates a guidance signal. When the target is obscured by smoke and fog, the position of the target in the geographic system can be deduced through this scheme, and the line of sight angle in the aircraft body coordinate system and the line of sight angular velocity in the stereoscopic line of sight system can be calculated, thereby achieving guidance. Compared with the prior art, the present application takes into account the moving position of the obscured target, minimizes the error to the greatest extent, and improves the accuracy of virtual guidance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flowchart of a virtual guidance method based on target position prediction provided in an embodiment of the present application; Figure 2 A simulation curve diagram of the predicted heading sight angle and the measured heading sight angle provided in the embodiment of the present application; Figure 3 A simulation curve diagram of the predicted pitch sight angle and the measured pitch sight angle provided in the embodiment of the present application; Figure 4 A simulation curve diagram of the predicted heading sight line angular velocity and the measured heading sight line angular velocity provided in the embodiment of the present application; Figure 5 A simulation graph of the predicted pitch line of sight angular velocity and the measured pitch line of sight angular velocity provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] As mentioned in the background technology, the present application proposes a virtual guidance method based on target position prediction, comprising the following steps: S100. Obtain the position of the current target in the image, recorded as the real target position; Wherein, the real target position can be obtained according to the recognition and tracking algorithm; S200. Calculate the latitude and longitude height vector of the target point according to the real target position, and record it as the real target latitude and longitude height vector; wherein the real target latitude and longitude height vector can be obtained by an infrared seeker and an inertial navigation system; comprising the following steps: S210. Calculate the sight angle vector of the target relative to the longitudinal axis of the aircraft in the aircraft body coordinate system according to the real target position, and record it as the real sight angle vector [ ], including the true heading sight angle and the true pitch sight angle; Among them, the aircraft body coordinate system is a commonly used coordinate system to describe the motion state of the aircraft, with the center of mass of the aircraft as the origin, the X-axis along the axis of the aircraft fuselage, pointing to the direction of the nose is positive; the Y-axis is perpendicular to the X-axis in the symmetry plane of the aircraft, pointing upward is positive; the Z-axis is perpendicular to the symmetry plane of the aircraft, and the direction is determined according to the right-hand rule. The calculation of the real sight angle vector based on the real target position is an existing technology and will not be repeated here; S220. Obtain the real-time attitude angle vector of the aircraft relative to the geographic coordinate system; The real-time attitude angle vector is obtained by the inertial navigation system. The real-time attitude angle vector includes the pitch angle, the yaw angle and the roll angle. The real-time attitude angle vector is recorded as [ ]; S230. Calculate the sight angle vector of the target in the inertial coordinate system according to the real sight angle vector and the real-time attitude angle vector, and record it as the real inertial system sight angle vector, wherein the real inertial system sight angle vector includes the real inertial system heading sight angle and the real inertial system pitch sight angle; comprising the following steps: S231. Constructing a first transformation matrix according to the real sight line angle vector and the real-time attitude angle vector, wherein the first transformation matrix is ​​a rotation matrix from a stereoscopic sight line coordinate system to a geographic coordinate system; The origin of the stereoscopic sight line coordinate system is the same as that of the aircraft body coordinate system, located at the center of mass of the aircraft, the X axis is along the direction of the line connecting the aircraft and the target, pointing to the target is positive, the Y axis is the heading axis, and the Z axis is the pitch axis. The coordinate system is obtained by rotating the heading sight line angle and the pitch sight line angle of the aircraft body coordinate system. The first transformation matrix is ​​shown as follows: Formula (1) S232. Constructing the first transformation matrix according to the real inertial system sight angle vector and the rotation angle, wherein the rotation angle is the rotation angle of the stereoscopic sight coordinate system relative to the inertial sight system; Wherein, it is assumed that the real inertial system line of sight angle vector is , the rotation angle is , the first transformation matrix can also be expressed as: Formula (2); S233. Calculate the value of the real inertial system sight angle vector according to the equivalent relationship; Since the left sides of formula (1) and formula (2) are the same, according to the equivalence relationship, the right sides of the formulas are also the same. According to the calculation, we get: Formula (3) S240. Obtaining the real-time latitude and longitude height vector of the aircraft; obtaining the real-time latitude and longitude height vector of the aircraft through an inertial navigation system; S250. Calculating the real target latitude and longitude height vector according to the real aircraft latitude and longitude height vector and the real inertial system line of sight angle vector; comprising the following steps: S251. Obtain the distance between the target and the aircraft, recorded as the real distance; Wherein, the aircraft is provided with a distance measuring device for obtaining the real distance; S252. Calculate a real latitude and longitude height difference vector according to the real inertial system sight angle vector and the real distance, wherein the real latitude and longitude height difference vector includes a latitude difference between the aircraft and the target, a longitude difference between the aircraft and the target, and a height difference between the aircraft and the target; From the geometric relationship, we can know that: Formula (4) In the formula, is the latitude difference (in meters), is the longitude difference (unit: meter), is the height difference, is the length of the projection of the line between the aircraft and the target in the horizontal direction, is the actual distance; Calculated by formula (4): Formula (5) S253. Calculate the real target latitude and longitude height vector according to the real latitude and longitude height difference vector and the real-time latitude and longitude height vector of the aircraft; The relationship between the real latitude and longitude height difference vector, the real-time latitude and longitude height vector of the aircraft, and the real target latitude and longitude height vector is shown in the following formula: Formula (6) In the formula, R 0=111.31955km, , , Respectively represent the latitude, altitude, and longitude of the latitude, longitude, and height vector of the real target; X M , Y M , Z M Respectively represent the latitude, altitude, and longitude of the real-time latitude, longitude, and altitude vector of the aircraft. Through formula (6), we can get: Formula (7) S300. Estimate the position and speed of the virtual target in the geographic coordinate system according to the latitude and longitude height vector of the real target, and record them as the predicted target real-time position vector and the predicted real-time speed vector respectively; The steps include: S310. According to the latitude in the latitude and longitude vector of the real target, the predicted real-time position of the target in the north direction and the predicted real-time speed in the north direction are estimated by the Kalman filter algorithm; comprising the following steps: Select the state variable as X= ,in, is the target north position, is the target northward speed, is the northward acceleration of the target; the acceleration is expressed by the Singer model, and the state equation is established as: Formula (8) The state transfer matrix is ​​as follows:

[0020] In the formula, is the reciprocal of the maneuvering time constant, i.e. the maneuvering frequency, usually The empirical range of is: when the target maneuver is a slow turn, The value of is 60s. When the target maneuver is an evasive maneuver, The value of is 20s. The process noise in formula (8) is: Formula (9) In the formula, is a white noise sequence. Discretize formula (8) to obtain: Formula (10) The discretized state transfer matrix is:

[0021] Where T is the sampling time interval. Discrete-time process noise W k The covariance matrix of is:

[0022] Take a smaller value. Q is a symmetric matrix, where: Formula (11) Taking the target position as the test value, the measurement matrix is:

[0023] Let the estimated state at time k be X k Affected by process noise series W k-1 Drive, the driving machine is described by the state process shown in the following formula: Formula (12) right The measurement satisfies the linear relationship, and the measurement equation is: Formula (13) in is the measured value, is the measurement noise sequence. Let for The estimated value of , the Kalman filter prediction process can be written as the following five equations: 1) State one-step prediction equation: Formula (14) 2) State estimation equation: Formula (15) 3) Filter gain: Formula (16) 4) One-step prediction mean square error: Formula (17) 5) Estimate mean square error: Formula (18) in, R k is the measurement noise variance matrix; Q k is the process noise variance matrix.

[0024] The Kalman filter prediction process is as follows: Set the initial state vector , taking the initial state vector as the estimated value of the previous moment Substitute into formula (14) to get the one-step prediction value of the current state , which includes preliminary predictions of the next moment's predicted real-time north position of the target, the predicted real-time north speed, and the predicted real-time north acceleration.

[0025] According to formula (17), the one-step prediction mean square error is calculated Then the filter gain is calculated according to formula (16): K k ; According to formula (15), the state is estimated. Z k is the measured value at the current moment, that is X T . The asynchronous prediction value and filter gain K k And the measured value Z k Substitute into the formula to get the estimated value of the current state , which includes the estimated values ​​of the target north position, target north velocity, and target north acceleration at the next moment after the update; Update the estimated mean square error according to formula (18) P k , prepare for the next iteration; Repeat the above steps to continuously update the target state estimate.

[0026] Through the above prediction process, as long as the initial state vector is known X 0 and initial mean square error P 0, you can solve k The state estimate at time k The predicted value at time +1, that is, the predicted real-time position of the target in the north direction, the predicted real-time speed in the north direction, and the predicted real-time acceleration in the north direction.

[0027] S320. According to the height of the latitude and longitude height vector of the real target, the predicted real-time position of the target in the celestial direction and the predicted real-time speed in the celestial direction are estimated by the Kalman filter algorithm; The method is the same as step S310, except that the initial state vector ; S330. According to the longitude in the latitude and longitude height vector of the real target, the real-time position of the predicted target in the east direction and the real-time speed predicted in the east direction are estimated by the Kalman filter algorithm; The method is the same as step S310, except that the initial state vector ; S340. Obtain the predicted target real-time position vector according to the predicted target real-time position in the north direction, the predicted target real-time position in the sky direction, and the predicted target real-time position in the east direction; obtain the predicted real-time speed vector according to the predicted real-time speed in the north direction, the predicted real-time speed in the sky direction, and the predicted real-time speed in the east direction.

[0028] S400. Calculate the sight angle vector of the virtual target in the aircraft body coordinate system according to the predicted target real-time position vector, and record it as the predicted sight angle vector; comprising the following steps: S410. Obtain the real-time latitude and longitude vector and the real-time attitude angle vector of the aircraft ; S420. Calculate the predicted longitude and latitude height difference vector according to the predicted target real-time position vector and the real-time longitude and latitude height vector of the aircraft; The predicted latitude and longitude height difference vector is calculated by the following formula: Formula (19) In the formula, X F Represents the real-time position of the predicted target in the north direction; Y F Represents the real-time position of the target predicted in the east direction, Z F Represents the predicted real-time position of the target in the celestial direction; represents the latitude difference between the aircraft and the virtual target, represents the height difference between the aircraft and the virtual target; Represents the longitude difference between the aircraft and the virtual target.

[0029] S430. Calculate the sight angle vector of the virtual target in the inertial coordinate system according to the predicted latitude and longitude height difference vector, and record it as the sight angle vector of the virtual target inertial system, and record it as , including the heading sight angle of the virtual target inertial system and the pitch sight angle of the virtual target inertial system; According to formula (19), we can get:

[0030] in, .

[0031] S440. Calculate the predicted sight angle vector according to the virtual target inertial system sight angle vector and the real-time attitude angle vector; comprising the following steps: S441. Constructing the first transformation matrix according to the predicted sight angle vector and the real-time posture angle vector; The first conversion matrix is ​​shown as follows: Formula (20) S442. construct the first transformation matrix according to the virtual target inertial system sight angle vector and the rotation angle; The first conversion matrix can also be expressed as: Formula (21) S443. Calculate the value of the predicted sight angle vector according to the equivalent relationship; Among them, the left side of the equal sign of formula (20) and formula (21) is the same. According to the equivalent relationship, we get: Formula (22) in, , a predicted elevation sight angle representing the predicted sight angle; A predicted heading sight angle representing the predicted sight angle.

[0032] S500. Calculate the line of sight angular velocity vector in the stereoscopic line of sight system according to the predicted real-time velocity vector, and record it as the predicted line of sight angular velocity vector; The steps include: S510. Obtaining a real-time velocity vector of the aircraft in the geographic coordinate system, recorded as the real-time velocity vector of the aircraft; wherein the real-time velocity vector of the aircraft can be obtained according to an inertial navigation system; S520. Calculate the line-of-sight angular velocity vector in the inertial line-of-sight system according to the real-time velocity vector of the aircraft and the predicted real-time velocity vector, and record it as the predicted inertial line-of-sight angular velocity vector; The steps include: S521. Obtaining a coordinate rotation matrix from the geographic coordinate system to the inertial line of sight system, recorded as a second transformation matrix; The second conversion matrix L1 is shown as follows: Formula (23) S522. Obtain the relative speed between the aircraft and the virtual target in the inertial line of sight system according to the second conversion matrix, the predicted real-time speed vector and the aircraft real-time speed vector; Wherein, the relative speed is expressed as follows: Formula (24) In the formula, V M represents the real-time velocity vector of the aircraft, V T Represents the predicted real-time velocity vector.

[0033] S523. Calculate the predicted inertial system line of sight angular velocity vector according to the relative velocity V gs ; This is achieved through the following formula: Formula (25) In the formula, represents the predicted inertial system heading line of sight angular velocity, Represents the predicted inertial frame pitch line of sight angular velocity.

[0034] S530. Converting the predicted inertial system line of sight angular velocity vector into the predicted line of sight angular velocity vector; S531. Obtain the coordinate rotation matrix from the inertial line of sight system to the stereoscopic line of sight system, recorded as the third transformation matrix; Wherein, the third conversion matrix is ​​shown as follows: Formula (26) S532. Calculate the predicted line of sight angular velocity vector according to the third transformation matrix and the predicted inertial system line of sight angular velocity vector, as shown in the following formula: Formula (27) In the formula, .

[0035] The virtual guidance method of the present invention is simulated and verified by simulation software, such as Figure 2-Figure 5 As shown, the measured heading sight angle, the measured pitch sight angle, the measured heading sight angular velocity, and the measured pitch sight angular velocity are the simulation output values ​​of the infrared seeker, and the predicted heading sight angle, the predicted pitch sight angle, the predicted heading sight angular velocity, and the predicted pitch sight angular velocity are the simulation values ​​obtained by the virtual guidance method of the present invention. The simulation results show that the accuracy of the virtual guidance signal provided by the present invention meets the use requirements.

[0036] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

Claims

1. A virtual guidance method based on target position prediction, characterized in that: The steps include: S100. Obtain the position of the current target in the image, recorded as the real target position; S200. Calculate the latitude and longitude height vector of the target point according to the real target position, and record it as the real target latitude and longitude height vector; S300. Estimate the position and speed of the virtual target in the geographic coordinate system according to the latitude and longitude height vector of the real target, and record them as the predicted target real-time position vector and the predicted real-time speed vector respectively; S400. Calculate the sight angle vector of the virtual target in the aircraft body coordinate system according to the predicted target real-time position vector, and record it as the predicted sight angle vector; S500. Calculate the line of sight angular velocity vector in the stereoscopic line of sight system according to the predicted real-time velocity vector, and record it as the predicted line of sight angular velocity vector.

2. The virtual guidance method based on target position prediction according to claim 1, characterized in that: Step S200 includes the following steps: S210. Calculate the sight angle vector of the target relative to the longitudinal axis of the aircraft in the aircraft body coordinate system according to the real target position, recorded as the real sight angle vector, including the real heading sight angle and the real pitch sight angle; S220. Obtain the real-time attitude angle vector of the aircraft relative to the geographic coordinate system; S230. Calculate the sight angle vector of the target in the inertial coordinate system according to the real sight angle vector and the real-time attitude angle vector, and record it as the real inertial system sight angle vector; S240. Obtain the real-time latitude and longitude height vector of the aircraft; S250. Calculate the real target longitude and latitude height vector according to the real-time longitude and latitude height vector of the aircraft and the real inertial system line of sight angle vector.

3. The virtual guidance method based on target position prediction according to claim 2, characterized in that: Step S250 includes the following steps: S251. Obtain the distance between the target and the aircraft, recorded as the real distance; S252. Calculate a real latitude and longitude height difference vector according to the real inertial system sight angle vector and the real distance, wherein the real latitude and longitude height difference vector includes a latitude difference between the aircraft and the target, a longitude difference between the aircraft and the target, and a height difference between the aircraft and the target; S253. Calculate the real target longitude and latitude height vector according to the real longitude and latitude height difference vector and the real-time longitude and latitude height vector of the aircraft.

4. The virtual guidance method based on target position prediction according to claim 2, characterized in that: Step S230 includes the following steps: S231. Constructing a first transformation matrix according to the real sight line angle vector and the real-time attitude angle vector, wherein the first transformation matrix is ​​a rotation matrix from a stereoscopic sight line coordinate system to a geographic coordinate system; S232. Constructing the first transformation matrix according to the real inertial system sight angle vector and the rotation angle, wherein the rotation angle is the rotation angle of the stereoscopic sight coordinate system relative to the inertial sight system; S233. Calculate the value of the real inertial system line of sight angle vector based on the equivalent relationship.

5. The virtual guidance method based on target position prediction according to claim 1, characterized in that: Step S300 includes the following steps: S310. According to the true target latitude and longitude, the predicted real-time position of the target in the north direction and the predicted real-time speed in the north direction are estimated by the Kalman filter algorithm; S320. According to the true target latitude and longitude, the predicted target real-time position and predicted real-time speed in the celestial direction are estimated by the Kalman filter algorithm; S330. According to the true target latitude and longitude, the real-time position of the target in the east direction and the real-time speed in the east direction are estimated by the Kalman filter algorithm; S340. Obtain the predicted target real-time position vector according to the predicted target real-time position in the north direction, the predicted target real-time position in the sky direction, and the predicted target real-time position in the east direction; obtain the predicted real-time speed vector according to the predicted real-time speed in the north direction, the predicted real-time speed in the sky direction, and the predicted real-time speed in the east direction.

6. The virtual guidance method based on target position prediction according to claim 1, characterized in that: Step S400 includes the following steps: S410. Obtain the real-time latitude and longitude height vector and the real-time attitude angle vector of the aircraft; S420. Calculate the predicted longitude and latitude height difference vector according to the predicted target real-time position vector and the real-time longitude and latitude height vector of the aircraft; S430. Calculate the sight angle vector of the virtual target in the inertial coordinate system according to the predicted latitude and longitude height difference vector, and record it as the sight angle vector of the virtual target inertial system; S440. Calculate the predicted sight angle vector based on the virtual target inertial system sight angle vector and the real-time attitude angle vector.

7. The virtual guidance method based on target position prediction according to claim 6, characterized in that: Step S440 includes the following steps: S441. Constructing the first transformation matrix according to the predicted sight angle vector and the real-time posture angle vector; S442. construct the first transformation matrix according to the virtual target inertial system sight angle vector and the rotation angle; S443. Calculate the value of the predicted sight angle vector based on the equivalent relationship.

8. The virtual guidance method based on target position prediction according to claim 1, characterized in that: Step S500 includes the following steps: S510. Obtain the real-time velocity vector of the aircraft in the geographic coordinate system, recorded as the real-time velocity vector of the aircraft; S520. Calculate the line-of-sight angular velocity vector in the inertial line-of-sight system according to the real-time velocity vector of the aircraft and the predicted real-time velocity vector, and record it as the predicted inertial line-of-sight angular velocity vector; S530. Convert the predicted inertial system line of sight angular velocity vector into the predicted line of sight angular velocity vector.

9. The virtual guidance method based on target position prediction according to claim 8, characterized in that: Step S520 includes the following steps: S521. Obtaining a coordinate rotation matrix from the geographic coordinate system to the inertial line of sight system, recorded as a second transformation matrix; S522. Obtain the relative speed between the aircraft and the virtual target in the inertial line of sight system according to the second conversion matrix, the predicted real-time speed vector and the aircraft real-time speed vector; S523. Obtain the predicted inertial system line-of-sight angular velocity vector according to the relative velocity calculation.

10. The virtual guidance method based on target position prediction according to claim 8, characterized in that: Step S530 includes the following steps: S531. Obtain the coordinate rotation matrix from the inertial line of sight system to the stereoscopic line of sight system, recorded as the third transformation matrix; S532. Calculate the predicted line of sight angular velocity vector based on the third transformation matrix and the predicted inertial system line of sight angular velocity vector.

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