A virtual guide method based on target position prediction

Abstract

The application provides a virtual guiding method based on target position prediction, which obtains the longitude, latitude and height vectors of a real target through an infrared seeker and an inertial navigation system; estimates the predicted target real-time position vector and the predicted real-time speed vector of a virtual target in a geographical 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 body line-of-sight system through the two vectors to generate a guiding signal. When the target is blocked by smoke and fog, the position of the target in the geographical system can be derived through the scheme, and the line-of-sight angle in the aircraft body coordinate system and the line-of-sight angular velocity in the body line-of-sight system can be calculated, so that the guiding is realized. Compared with the prior art, the moving position of the blocked target is considered, the error is minimized, and the precision of the virtual guiding is improved.

Description

TECHNICAL FIELD

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

[0002] In modern military combat systems, aircraft play a very important role. Aircraft are often equipped with various advanced detection devices to accurately obtain target information in combat scenarios, and infrared cameras are a very critical device. The infrared camera carried on the aircraft can take pictures to determine the position of the target in the image, and the infrared seeker is a device for accurately guiding the aircraft to track the target based on the infrared camera.

[0003] However, as the modern battlefield environment becomes more and more complex, the use of interference sources such as smoke and fire is becoming more and more frequent. This makes the problem of infrared seekers being easily disturbed by smoke and cloud stand out, and this problem has become a major factor restricting the wider application of infrared seekers. When the target is obscured by smoke and cloud, etc., the virtual guidance strategy can be used to calculate the virtual line of sight angle and virtual line of sight angle velocity as guidance information.

[0004] The commonly used virtual guidance strategy does not consider the movement of the target or does not use inertial navigation information, but only uses the measurement value of the infrared seeker to approximately compensate for part of the error term to extrapolate the line of sight angle and line of sight angle velocity. The above methods all belong to relatively simplified methods, and the error of the output guidance information is large. SUMMARY

[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:

[0006] S100. Obtain the position of the current target in the image, denoted as the real target position;

[0007] S200. Calculate the target point latitude and longitude vector according to the real target position, denoted as the real target latitude and longitude vector;

[0008] S300. Estimate the position and speed of the virtual target in the geographic coordinate system according to the real target latitude and longitude vector, denoted as the predicted target real-time position vector and the predicted real-time speed vector, respectively;

[0009] S400. Calculate the virtual target line of sight angle vector in the aircraft body coordinate system according to the predicted target real-time position vector, denoted as the predicted line of sight angle vector;

[0010] S500. Calculate a line-of-sight angular velocity vector in a body line-of-sight coordinate system according to the predicted real-time velocity vector, denoted as a predicted line-of-sight angular velocity vector.

[0011] According to the technical scheme provided in the embodiments of the present application, step S200 comprises the following steps:

[0012] S210. Calculate a line-of-sight angular vector of the target relative to the longitudinal axis of the aircraft in a body coordinate system of the aircraft according to the real target position, denoted as a real line-of-sight angular vector, comprising a real heading line-of-sight angle and a real pitch line-of-sight angle;

[0013] S220. Obtain a real-time attitude angular vector of the aircraft relative to a geographic coordinate system;

[0014] S230. Calculate a line-of-sight angular vector of the target in an inertial coordinate system according to the real line-of-sight angular vector and the real-time attitude angular vector, denoted as a real inertial line-of-sight angular vector;

[0015] S240. Obtain a real-time longitude-latitude-height vector of the aircraft;

[0016] S250. Calculate the real target longitude-latitude-height vector according to the real-time longitude-latitude-height vector of the aircraft and the real inertial line-of-sight angular vector.

[0017] According to the technical scheme provided in the embodiments of the present application, step S250 comprises the following steps:

[0018] S251. Obtain a distance between the target and the aircraft, denoted as a real distance;

[0019] S252. Calculate a real longitude-latitude-height difference vector according to the real inertial line-of-sight angular vector and the real distance, the real longitude-latitude-height difference vector comprising 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;

[0020] S253. Calculate the real target longitude-latitude-height vector according to the real longitude-latitude-height difference vector and the real-time longitude-latitude-height vector of the aircraft.

[0021] According to the technical scheme provided in the embodiments of the present application, step S230 comprises the following steps:

[0022] S231. Construct a first conversion matrix according to the real line-of-sight angular vector and the real-time attitude angular vector, the first conversion matrix being a rotation matrix from a body line-of-sight coordinate system to a geographic coordinate system;

[0023] S232. Construct the first conversion matrix according to the real inertial line-of-sight angular vector and a rotation angle, wherein the rotation angle is a rotation angle of the body line-of-sight coordinate system relative to an inertial line-of-sight system;

[0024] S233. Calculate the value of the true inertial system line-of-sight angle vector according to the equivalence relationship.

[0025] According to the technical scheme provided by the embodiment of the present application, step S300 comprises the following steps:

[0026] S310. Estimate the north direction predicted target real-time position and the north direction predicted real-time speed according to the true target latitude and longitude by Kalman filtering algorithm;

[0027] S320. Estimate the zenith direction predicted target real-time position and the zenith direction predicted real-time speed according to the true target latitude and longitude by Kalman filtering algorithm;

[0028] S330. Estimate the east direction predicted target real-time position and the east direction predicted real-time speed according to the true target latitude and longitude by Kalman filtering algorithm;

[0029] S340. Obtain the predicted target real-time position vector according to the north direction predicted target real-time position, the zenith direction predicted target real-time position and the east direction predicted target real-time position; obtain the predicted real-time speed vector according to the north direction predicted real-time speed, the zenith direction predicted real-time speed and the east direction predicted real-time speed.

[0030] According to the technical scheme provided by the embodiment of the present application, step S400 comprises the following steps:

[0031] S410. Obtain the real-time latitude and longitude vector of the aircraft and the real-time attitude angle vector;

[0032] S420. Calculate the predicted latitude and longitude difference vector according to the predicted target real-time position vector and the real-time latitude and longitude vector of the aircraft;

[0033] S430. Calculate the line-of-sight angle vector of the virtual target in the inertial coordinate system, denoted as the virtual target inertial system line-of-sight angle vector, according to the predicted latitude and longitude difference vector;

[0034] S440. Calculate the predicted line-of-sight angle vector according to the virtual target inertial system line-of-sight angle vector and the real-time attitude angle vector.

[0035] According to the technical scheme provided by the embodiment of the present application, step S440 comprises the following steps:

[0036] S441. Construct the first conversion matrix according to the predicted line-of-sight angle vector and the real-time attitude angle vector;

[0037] S442. Construct the first conversion matrix according to the virtual target inertial system line-of-sight angle vector and the rotation angle;

[0038] S443. Calculate the value of the predicted line-of-sight angular vector according to the equivalence relationship.

[0039] According to the technical scheme provided by the embodiment of the present application, the step S500 comprises the following steps:

[0040] S510. Obtain a real-time speed vector of the aircraft in a geographical coordinate system, denoted as a real-time speed vector of the aircraft;

[0041] S520. Calculate a line-of-sight angular velocity vector in an inertial line-of-sight system according to the real-time speed vector of the aircraft and the predicted real-time speed vector, denoted as a predicted inertial system line-of-sight angular velocity vector;

[0042] S530. Convert the predicted inertial system line-of-sight angular velocity vector into the predicted line-of-sight angular velocity vector.

[0043] According to the technical scheme provided by the embodiment of the present application, the step S520 comprises the following steps:

[0044] S521. Obtain a coordinate rotation matrix from the geographical coordinate system to the inertial line-of-sight system, denoted as a second conversion matrix;

[0045] S522. Obtain a 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 real-time speed vector of the aircraft;

[0046] S523. Calculate the predicted inertial system line-of-sight angular velocity vector according to the relative speed.

[0047] According to the technical scheme provided by the embodiment of the present application, the step S530 comprises the following steps:

[0048] S531. Obtain a coordinate rotation matrix from the inertial line-of-sight system to the body line-of-sight system, denoted as a third conversion matrix;

[0049] S532. Calculate the predicted line-of-sight angular velocity vector according to the third conversion matrix and the predicted inertial system line-of-sight angular velocity vector.

[0050] 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 solution, 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

[0051] Figure 1 A flowchart of a virtual guidance method based on target position prediction provided in an embodiment of the present application;

[0052] Figure 2 A simulation curve diagram of the predicted heading sight angle and the measured heading sight angle provided in an embodiment of the present application;

[0053] Figure 3 A simulation graph showing the predicted and measured pitch sight angles provided in an embodiment of the present application;

[0054] Figure 4 A simulation graph showing the predicted heading sight line angular velocity and the measured heading sight line angular velocity provided in an embodiment of the present application;

[0055] Figure 5 This is a simulation curve diagram of the predicted pitch line of sight angular velocity and the measured pitch line of sight angular velocity provided in the embodiment of the present application. DETAILED DESCRIPTION

[0056] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0057] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this 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.

[0058] As mentioned in the background technology, this application proposes a virtual guidance method based on target position prediction, comprising the following steps:

[0059] S100. Obtain the current target position in the image, recorded as the true target position;

[0060] wherein the real target position can be obtained according to a recognition tracking algorithm;

[0061] S200. calculating a target point longitude-latitude-height vector according to the real target position, denoted as a real target longitude-latitude-height vector; wherein the real target longitude-latitude-height vector can be obtained through an infrared seeker and an inertial navigation system; comprising the following steps:

[0062] S210. calculating a line-of-sight angle vector of the target relative to the longitudinal axis of the aircraft in the body coordinate system of the aircraft according to the real target position, denoted as a real line-of-sight angle vector ], comprising a real heading line-of-sight angle and a real pitch line-of-sight angle;

[0063] wherein the body coordinate system of the aircraft is a commonly used coordinate system for describing the motion state of the aircraft, with the mass center of the aircraft as the origin, the X-axis along the axis of the aircraft body, pointing to the head direction as positive; the Y-axis perpendicular to the X-axis in the symmetry plane of the aircraft, pointing upward as positive; and the Z-axis perpendicular to the symmetry plane of the aircraft, the direction determined according to the right-hand rule. The real line-of-sight angle vector calculated according to the real target position is a prior art, which will not be described here;

[0064] S220. obtaining a real-time attitude angle vector of the aircraft relative to the geographic coordinate system;

[0065] The real-time attitude angle vector is obtained through an inertial navigation system, and the real-time attitude angle vector comprises a pitch angle, a yaw angle and a roll angle, denoted as ];

[0066] S230. calculating a line-of-sight angle vector of the target in the inertial coordinate system according to the real line-of-sight angle vector and the real-time attitude angle vector, denoted as a real inertial system line-of-sight angle vector, the real inertial system line-of-sight angle vector comprising a real inertial system heading line-of-sight angle and a real inertial system pitch line-of-sight angle; comprising the following steps:

[0067] S231. constructing a first conversion matrix according to the real line-of-sight angle vector and the real-time attitude angle vector, the first conversion matrix being a rotation matrix from the body line-of-sight coordinate system to the geographic coordinate system;

[0068] wherein the origin of the body line-of-sight coordinate system is the same as the body coordinate system of the aircraft, located at the mass center of the aircraft, the X-axis along the direction of the line connecting the aircraft and the target, pointing to the target as positive, the Y-axis being the heading axis, and the Z-axis being the pitch axis, the coordinate system being obtained by rotating the heading line-of-sight angle and the pitch line-of-sight angle from the body coordinate system of the aircraft. The first conversion matrix is shown in the following formula:

[0069] Formula (1)

[0070] S232. Constructing the first conversion matrix according to the real inertial system line-of-sight angle vector and a rotation angle, wherein the rotation angle is a rotation angle of the body line-of-sight coordinate system relative to the inertial line-of-sight system;

[0071] wherein it is assumed that the real inertial system line-of-sight angle vector is , the rotation angle is , and the first conversion matrix can also be expressed as:

[0072] Formula (2);

[0073] S233. Calculating the value of the real inertial system line-of-sight angle vector according to the equivalence relationship;

[0074] Since the left sides of Formula (1) and Formula (2) are the same, according to the equivalence relationship, the right sides are also the same, and according to the calculation, it is obtained that:

[0075] Formula (3)

[0076] S240. Obtaining a real-time latitude and longitude height vector of an aircraft; and obtaining the real-time latitude and longitude height vector of the aircraft through an inertial navigation system;

[0077] S250. Calculating a real target latitude and longitude height vector according to the real-time latitude and longitude height vector of the aircraft and the real inertial system line-of-sight angle vector; comprising the following steps:

[0078] S251. Obtaining a distance between a target and the aircraft, denoted as a real distance;

[0079] wherein a distance measuring device is arranged on the aircraft, and is used to obtain the real distance;

[0080] S252. Calculating a real latitude and longitude height difference vector according to the real inertial system line-of-sight angle vector and the real distance, wherein the real latitude and longitude height difference vector comprises 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;

[0081] It can be known from a geometric relationship that:

[0082] Formula (4)

[0083] wherein is the latitude difference (unit: meter), is the longitude difference (unit: meter), is the height difference, is a length of a projection of a line connecting the aircraft and the target in a horizontal direction, is the real distance;

[0084] Calculated by formula (4):

[0085] Formula (5)

[0086] S253. Calculate the true target latitude and longitude height vector based on the true latitude and longitude height difference vector and the real-time latitude and longitude height vector of the aircraft;

[0087] The relationship between the true latitude and longitude height difference vector, the real-time latitude and longitude height vector of the aircraft, and the true target latitude and longitude height vector is shown in the following formula:

[0088] Formula (6)

[0089] Where, R 0=111.31955km, , , Represent the latitude, altitude and longitude of the true target latitude, longitude and altitude vector respectively; X M , Y M , Z M Represent the latitude, altitude, and longitude of the real-time latitude, longitude, and altitude vector of the aircraft, respectively. Formula (6) can be used to obtain:

[0090] Formula (7)

[0091] S300. According to the real target latitude and longitude high vector, estimate the position and speed of the virtual target in the geographic coordinate system, respectively recorded as the predicted target real-time position vector and the predicted real-time speed vector;

[0092] The steps include:

[0093] S310. Based on the latitude in the true target latitude and longitude height vector, 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:

[0094] 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:

[0095] Formula (8)

[0096] The state transfer matrix is ​​as follows:

[0097]

[0098] where, is the inverse of the maneuver time constant, i.e., the maneuver frequency, usually The empirical value range of is: when the target maneuver form is the airplane slow turn, The value of is 60 s, when the target maneuver form is the escape maneuver, The value of is 20 s. The process noise in equation (8) is:

[0099] Equation (9)

[0100] where, is a white noise sequence. Discretize equation (8) to obtain:

[0101] Equation (10)

[0102] The discretized state transition matrix is:

[0103]

[0104] where, T is the sampling time interval. The discretized time process noise W k The covariance matrix of is:

[0105]

[0106] A smaller value can be taken, Q is a symmetric matrix, where:

[0107] Equation (11)

[0108] Taking the target position as the test value, the measurement matrix is:

[0109]

[0110] Let the estimated state of the target at time k be X k Driven by the process noise sequence W k-1 The driving machine is described by the state process as shown in the following equation:

[0111] Equation (12)

[0112] The measurement of satisfies a linear relationship, and the measurement equation is:

[0113] Equation (13)

[0114] where is the measurement value, is the measurement noise sequence. Let be the estimate of

[0115] 1) State one-step prediction equation:

[0116] Equation (14)

[0117] 2) State estimation equation:

[0118] Equation (15)

[0119] 3) Filter gain:

[0120] Equation (16)

[0121] 4) One-step prediction mean square error:

[0122] Equation (17)

[0123] 5) Estimation mean square error:

[0124] Equation (18)

[0125] where, R k is the measurement noise variance matrix; Q k is the process noise variance matrix.

[0126] The Kalman filter prediction process is as follows:

[0127] Set the initial state vector , and substitute the initial state vector as the estimated value at the last time into equation (14) to obtain the state one-step prediction value at the current time , which contains the preliminary prediction of the target real-time position in the north direction, the predicted real-time speed in the north direction, and the predicted real-time acceleration in the north direction at the next time.

[0128] Calculate the one-step prediction mean square error according to equation (17). Then calculate the filter gain K k according to equation (16);

[0129] Perform state estimation according to equation (15), at which time Z kis the measured value at the current moment, that is X T . The asynchronous prediction value and filter gain K k and measured values Z k Substitute into the formula to get the current state estimate , which includes the updated estimated values ​​of the target north position, target north velocity, and target north acceleration at the next moment;

[0130] Update the estimated mean square error according to formula (18) P k , prepare for the next iteration;

[0131] Repeat the above steps to continuously update the target state estimate.

[0132] 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 it 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.

[0133] S320. According to the height of the true target latitude and longitude height vector, 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;

[0134] The method is the same as step S310, except that the initial state vector ;

[0135] S330. According to the longitude of the true target latitude and longitude high vector, 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;

[0136] The method is the same as step S310, except that the initial state vector ;

[0137] S340. Obtain the predicted target real-time position vector based on 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 based on 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.

[0138] S400. Calculate a virtual target line-of-sight angular vector in a body coordinate system of the aircraft according to the predicted target real-time position vector, denoted as a predicted line-of-sight angular vector; including the following steps:

[0139] S410. Obtain the aircraft real-time latitude-longitude-height vector and the real-time attitude angle vector

[0140] S420. Calculate a predicted latitude-longitude-height difference vector according to the predicted target real-time position vector and the aircraft real-time latitude-longitude-height vector;

[0141] The predicted latitude-longitude-height difference vector is calculated by the following formula:

[0142] Formula (19)

[0143] In the formula, X F represents the north direction predicted target real-time position; Y F represents the east direction predicted target real-time position, Z F represents the sky direction predicted target real-time position; 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.

[0144] S430. Calculate a virtual target line-of-sight angular vector in an inertial coordinate system according to the predicted latitude-longitude-height difference vector, denoted as a virtual target inertial system line-of-sight angular vector, denoted as , including a virtual target inertial system heading line-of-sight angle and a virtual target inertial system pitch line-of-sight angle;

[0145] The predicted latitude-longitude-height difference vector can be obtained according to formula (19):

[0146]

[0147] In the formula, .

[0148] S440. Calculate the predicted line-of-sight angular vector according to the virtual target inertial system line-of-sight angular vector and the real-time attitude angle vector; including the following steps:

[0149] S441. Construct the first conversion matrix according to the predicted line-of-sight angular vector and the real-time attitude angle vector;

[0150] The first conversion matrix is shown in the following formula:

[0151] ​ Equation (20)

[0152] S442. Constructing the first conversion matrix according to the virtual target inertial system line-of-sight angle vector and the rotation angle;

[0153] The first conversion matrix can also be expressed as:

[0154] Equation (21)

[0155] S443. Calculating the value of the predicted line-of-sight angle vector according to the equivalent relationship;

[0156] Wherein, the left side of Equation (20) and Equation (21) is the same, and according to the equivalent relationship, it is obtained that:

[0157] Equation (22)

[0158] Wherein, , The predicted pitch line-of-sight angle represents the predicted line-of-sight angle. The predicted heading line-of-sight angle represents the predicted line-of-sight angle.

[0159] S500. Calculating the line-of-sight angular velocity vector in the body line-of-sight system according to the predicted real-time velocity vector, denoted as the predicted line-of-sight angular velocity vector;

[0160] Including the following steps:

[0161] S510. Obtaining the real-time velocity vector of the aircraft in the geographic coordinate system, denoted as the aircraft real-time velocity vector; wherein the aircraft real-time velocity vector can be obtained according to the inertial navigation system;

[0162] S520. Calculating the line-of-sight angular velocity vector in the inertial line-of-sight system according to the aircraft real-time velocity vector and the predicted real-time velocity vector, denoted as the predicted inertial system line-of-sight angular velocity vector;

[0163] Including the following steps:

[0164] S521. Obtaining the coordinate rotation matrix from the geographic coordinate system to the inertial line-of-sight system, denoted as the second conversion matrix;

[0165] Wherein, the second conversion matrix L1 is as follows:

[0166] Equation (23)

[0167] S522. Obtaining the relative velocity between the aircraft and the virtual target in the inertial line-of-sight system according to the second conversion matrix, the predicted real-time velocity vector and the aircraft real-time velocity vector;

[0168] wherein the relative velocity is given by:

[0169] Equation (24)

[0170] wherein, V M represents the real-time velocity vector of the aircraft, V T represents the predicted real-time velocity vector.

[0171] S523. calculating the predicted inertial LOS angular velocity vector according to the relative velocity V gs ;

[0172] by the following equation:

[0173] Equation (25)

[0174] wherein, represents the predicted inertial heading LOS angular velocity, represents the predicted inertial pitch LOS angular velocity.

[0175] S530. converting the predicted inertial LOS angular velocity vector into the predicted LOS angular velocity vector;

[0176] S531. obtaining a coordinate rotation matrix from the inertial LOS system to the body LOS system, denoted as a third conversion matrix;

[0177] wherein the third conversion matrix is given by:

[0178] Equation (26)

[0179] S532. calculating the predicted LOS angular velocity vector according to the third conversion matrix and the predicted inertial LOS angular velocity vector, given by:

[0180] Equation (27)

[0181] wherein, .

[0182] The virtual guidance method in the present application is simulated and verified by simulation software, such as MATLAB, as follows: Figures 2-5As shown in the figure, the measured heading line-of-sight angle, the measured pitch line-of-sight angle, the measured heading line-of-sight angular velocity and the measured pitch line-of-sight angular velocity are the simulation output values of the infrared seeker, and the predicted heading line-of-sight angle, the predicted pitch line-of-sight angle, the predicted heading line-of-sight angular velocity and the predicted pitch line-of-sight angular velocity are the simulation values obtained by the virtual guidance method of the application, and the simulation results show that the virtual guidance signal precision given by the application meets the use requirements.

[0183] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. A virtual guidance method based on target position prediction, characterized by, The method comprises the following steps: S100. Obtain a position of a current target in an image, denoted as a real target position; S200. Calculate a target point latitude-longitude-height vector according to the real target position, denoted as a real target latitude-longitude-height vector; S300. Estimate a position and a speed of a virtual target in a geographical coordinate system according to the real target latitude-longitude-height vector, denoted as a predicted target real-time position vector and a predicted real-time speed vector respectively; S400. Calculate a line-of-sight angle vector of the virtual target in a vehicle body coordinate system according to the predicted target real-time position vector, denoted as a predicted line-of-sight angle vector; S500. Calculate a line-of-sight angular velocity vector in the body line-of-sight system according to the predicted real-time speed vector, denoted as a predicted line-of-sight angular velocity vector; Step S400 comprises the following steps: S410. Obtain a real-time latitude-longitude-height vector and a real-time attitude angle vector of the vehicle; S420. Calculate a predicted latitude-longitude-height difference vector according to the predicted target real-time position vector and the real-time latitude-longitude-height vector of the vehicle; S430. Calculate a line-of-sight angle vector of the virtual target in an inertial coordinate system according to the predicted latitude-longitude-height difference vector, denoted as a virtual target inertial system line-of-sight angle vector; S440. Calculate the predicted line-of-sight angle vector according to the virtual target inertial system line-of-sight angle vector and the real-time attitude angle vector.

2. The virtual guidance method based on target position prediction according to claim 1, characterized in that, Step S200 comprises the following steps: S210. Calculate a line-of-sight angle vector of the target relative to a longitudinal axis of the vehicle in the vehicle body coordinate system according to the real target position, denoted as a real line-of-sight angle vector, comprising a real heading line-of-sight angle and a real pitch line-of-sight angle; S220. Obtain a real-time attitude angle vector of the vehicle relative to the geographical coordinate system; S230. Calculate a line-of-sight angle vector of the target in the inertial coordinate system according to the real line-of-sight angle vector and the real-time attitude angle vector, denoted as a real inertial system line-of-sight angle vector; S240. Obtain a real-time latitude-longitude-height vector of the vehicle; S250. Calculate the real target latitude-longitude-height vector according to the real-time latitude-longitude-height vector of the vehicle 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 comprises the following steps: S251. Obtain a distance between the target and the vehicle, denoted as a real distance; S252. Calculate a real latitude-longitude-height difference vector according to the real inertial system line-of-sight angle vector and the real distance, the real latitude-longitude-height difference vector comprising a latitude difference between the vehicle and the target, a longitude difference between the vehicle and the target, and a height difference between the vehicle and the target; S253. Calculate the real target latitude-longitude-height vector according to the real latitude-longitude-height difference vector and the real-time latitude-longitude-height vector of the vehicle.

4. The virtual guide method based on target position prediction according to claim 2, characterized by, Step S230 comprises the following steps: S231. Construct a first conversion matrix according to the real line-of-sight angle vector and the real-time attitude angle vector, the first conversion matrix being a rotation matrix from the body line-of-sight coordinate system to the geographical coordinate system; S232. Construct the first conversion matrix according to the real inertial system line-of-sight angle vector and a rotation angle, wherein the rotation angle is a rotation angle of the body line-of-sight coordinate system relative to the inertial line-of-sight system; S233. Calculate the value of the true inertial line-of-sight angular vector according to the equivalence relationship.

5. The virtual guide method based on target position prediction according to claim 1, characterized by, Step S300 includes the following steps: S310. Estimate the north direction predicted target real-time position and the north direction predicted real-time speed according to the true target longitude and latitude by Kalman filtering algorithm; S320. Estimate the zenith direction predicted target real-time position and the zenith direction predicted real-time speed according to the true target longitude and latitude by Kalman filtering algorithm; S330. Estimate the east direction predicted target real-time position and the east direction predicted real-time speed according to the true target longitude and latitude by Kalman filtering algorithm; S340. Obtain the predicted target real-time position vector according to the north direction predicted target real-time position, the zenith direction predicted target real-time position and the east direction predicted target real-time position; obtain the predicted real-time speed vector according to the north direction predicted real-time speed, the zenith direction predicted real-time speed and the east direction predicted real-time speed. 6.The virtual guide method based on target position prediction according to claim 4, characterized in that, Step S440 includes the following steps: S441. Construct the first conversion matrix according to the predicted line-of-sight angular vector and the real-time attitude angular vector; S442. Construct the first conversion matrix according to the virtual target inertial line-of-sight angular vector and the rotation angle; S443. Calculate the value of the predicted line-of-sight angular vector according to the equivalence relationship. 7.The virtual guidance method based on target position prediction according to claim 1, wherein, Step S500 includes the following steps: S510. Obtain the real-time speed vector of the aircraft in the geographical coordinate system, denoted as aircraft real-time speed vector; S520. Calculate the line-of-sight angular velocity vector in the inertial line-of-sight system, denoted as predicted inertial line-of-sight angular velocity vector, according to the aircraft real-time speed vector and the predicted real-time speed vector; S530. Convert the predicted inertial line-of-sight angular velocity vector to the predicted line-of-sight angular velocity vector. 8.The virtual guidance method based on target position prediction according to claim 7, characterized in that, Step S520 includes the following steps: S521. Obtain the coordinate rotation matrix from the geographical coordinate system to the inertial line-of-sight system, denoted as second conversion 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. Calculate the predicted inertial line-of-sight angular velocity vector according to the relative speed. 9.The virtual guide method based on target position prediction according to claim 7, characterized in that, Step S530 includes the following steps: S531. Obtain the coordinate rotation matrix from the inertial line-of-sight system to the body line-of-sight system, denoted as third conversion matrix; S532. Calculate the predicted line-of-sight angular velocity vector according to the third conversion matrix and the predicted inertial line-of-sight angular velocity vector.

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