An aircraft formation cooperative guidance method

Abstract

The application discloses a kind of aircraft formation cooperative guidance methods, comprising the following steps: S 1, establish in aircraft and target relative motion model, design the kinematic model of aircraft under relative motion model;S2, obtain aircraft relative target acceleration;S3, according to target flight state, obtain aircraft guidance instruction.The aircraft formation cooperative guidance method disclosed in the application is not easy to lose target, and improves the success rate of aircraft interception to target.

Description

Technical Field

[0001] This invention relates to a method for coordinated guidance of aircraft formations, belonging to the field of aircraft control technology. Background Technology

[0002] Traditional guidance laws, such as proportional guidance and enhanced proportional guidance, can only achieve zero miss attack. Ballistic shaping guidance laws add landing constraints to the zero miss attack.

[0003] These traditional guidance methods cannot achieve time-coordination between aircraft attacks; multiple aircraft cannot reach the target position simultaneously, easily leading to interception failure. Although some coordinated interception guidance methods exist that enable aircraft to reach the target position according to the expected time, the error between the time the aircraft arrives at the target and the expected time is relatively large, usually exceeding 0.4 seconds. Since the target is generally moving at high speed, such a large error can easily allow the target to escape interception.

[0004] During coordinated attacks or interceptions, the guidance trajectory of an aircraft may be curved, causing the target to go out of the seeker's field of view during the aircraft's maneuver to adjust its flight trajectory. Therefore, a single coordinated guidance law is difficult to meet the requirements of the seeker's field of view limit, which may lead to the problem that the target leaves the aircraft's field of view during the aircraft's tracking process, resulting in the aircraft's tracking failure.

[0005] In addition, when intercepting aerial targets, most existing guidance laws are designed for stationary or slowly moving targets, without considering the acceleration of the aircraft when it tracks the target's position. This results in a large acceleration difference between the aircraft and the target. If the target suddenly changes its acceleration drastically during the contact process, the large difference in the direction and magnitude of the acceleration between the aircraft and the target can easily cause the aircraft to be unable to track the target's acceleration change in time, resulting in the target escaping the aircraft's interception.

[0006] For the reasons mentioned above, it is necessary to propose a cooperative guidance method for maneuvering targets that can solve one of the aforementioned problems. Summary of the Invention

[0007] To overcome the above problems, the inventors conducted in-depth research and designed a cooperative guidance method for aircraft formations, comprising the following steps:

[0008] S1. Based on the relative motion model between the aircraft and the target, design the kinematic model of the aircraft under the relative motion model;

[0009] S2. Obtain the aircraft's acceleration relative to the target;

[0010] S3. Obtain guidance commands for the aircraft based on the target's flight status.

[0011] Furthermore, the aircraft is multiple, and the initial positions of the multiple aircraft are different.

[0012] Furthermore, in the relative motion model between the aircraft and the target, the target is set to be in a relatively stationary state.

[0013] Furthermore, in S1, the relative motion model between the aircraft and the target can be represented as:

[0014]

[0015]

[0016] a R =cos(θ) M -θ R )a M -cos(θ T -θ R )a T

[0017] Where, θ R θ represents the relative track angle between the aircraft and the target. M θ represents the flight path angle of the aircraft. T The target's trajectory angle, k = V T / V M ;

[0018] V R V represents the relative velocity between the aircraft and the target. M V represents the speed of the aircraft. T Indicates the target's speed;

[0019] a R a represents the relative acceleration between the aircraft and the target. M a represents the acceleration of an aircraft perpendicular to its velocity. T This represents the acceleration of a target perpendicular to its velocity.

[0020] Furthermore, the kinematic model of the aircraft is represented as follows:

[0021]

[0022] Where r represents the relative distance between the aircraft and the target, q represents the line-of-sight angle between the target and the aircraft, t represents time, and η R This represents the virtual perspective of the aircraft and the target, specifically the difference between the aircraft's trajectory angle and the target's line-of-sight angle in its relative coordinate system, and has V. R =V M -V T a R =aM -a T .

[0023] Furthermore, in S2, the acceleration of the aircraft relative to the target can be expressed as:

[0024]

[0025]

[0026]

[0027] r go * =V R (T d -t)

[0028]

[0029] Among them, T d Let t be the expected attack time of the aircraft, m and n be the guidance coefficients, ε represent the remaining flight distance error, and a be the guidance coefficients. p r go * , This is an intermediate parameter.

[0030] Preferably, the target flight state refers to the target being in a state of being stationary, moving at a constant speed, or moving at a variable speed.

[0031] When the target is stationary, the aircraft's guidance commands are:

[0032]

[0033] When the target is in uniform motion, the guidance command for the aircraft is:

[0034]

[0035] When the target is in a state of variable speed motion, the guidance command of the aircraft is:

[0036]

[0037] Preferably, a threshold is set for the remaining flight distance error. When the remaining flight distance error is less than the threshold, the guidance command in step S3 is adjusted to:

[0038] When the target is stationary, the guidance command for the aircraft is:

[0039]

[0040] When the target is in uniform motion, the guidance command of the aircraft is:

[0041]

[0042] When the target is in a state of variable speed motion, the guidance command of the aircraft is:

[0043]

[0044] Preferably, the threshold is set to V. M *0.01(s), where s represents seconds.

[0045] The beneficial effects of this invention include:

[0046] (1) The problem of a constant-speed aircraft intercepting a maneuvering target is transformed into the problem of a variable-speed aircraft tracking a stationary target. This reduces the number of control variables, makes the obtained guidance commands simpler, reduces the amount of guidance calculation and the computing power requirements of the guidance chip, and improves the speed of guidance rate calculation.

[0047] (2) The introduction of a virtual perspective in the guidance commands makes it less likely for the aircraft to lose the target and increases its applicability;

[0048] (3) When multiple aircraft meet at the target, the acceleration is relatively small, which avoids the saturation of terminal acceleration and provides conditions for intercepting maneuvering targets;

[0049] (4) The guidance method provided by the present invention has a small error between the actual time of the aircraft reaching the target and the set expected time, making it difficult for the target to escape the interception. Attached Figure Description

[0050] Figure 1 A flowchart of the aircraft formation cooperative guidance method according to the present invention is shown;

[0051] Figure 2 This illustrates the geometric motion relationship of an aircraft tracking a maneuvering target in a geodetic coordinate system according to the present invention.

[0052] Figure 3 The geometric relationship between the aircraft and the target is shown in the relative motion model of the aircraft tracking the maneuvering target according to the present invention;

[0053] Figure 4 The simulation results of the interception trajectories of the aircraft in Example 1 and Comparative Example 1 are shown.

[0054] Figure 5 The simulation results of the absolute acceleration of the aircraft and the target in Example 1 are shown;

[0055] Figure 6 The simulation results of the aircraft acceleration command in Example 2 and Comparative Example 2 are shown when the target is aT1.

[0056] Figure 7 The simulation results of the aircraft acceleration command in Example 2 and Comparative Example 2 are shown when the target is aT2. Detailed Implementation

[0057] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0058] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0059] A method for cooperative guidance of aircraft formations according to the present invention includes the following steps:

[0060] S1. Based on the relative motion model between the aircraft and the target, design the kinematic model of the aircraft under the relative motion model;

[0061] S2. Obtain the aircraft's acceleration relative to the target;

[0062] S3. Obtain guidance commands for the aircraft based on the target's flight status.

[0063] Furthermore, in this invention, there are multiple aircraft, and the initial positions of the multiple aircraft are different.

[0064] Furthermore, multiple aircraft simultaneously arrive at the target location to intercept the target.

[0065] According to the present invention, in S1, in the relative motion model between the aircraft and the target, the target is set to a relatively stationary state.

[0066] By setting the target to a relatively stationary state in the relative motion model, the problem of a constant-speed aircraft intercepting a maneuvering target is transformed into the problem of a variable-speed aircraft tracking a stationary target. This reduces the number of control variables, makes the obtained guidance commands simpler, lowers the guidance calculation load and the computing power requirements of the guidance chip, and improves the calculation speed when obtaining the aircraft's acceleration.

[0067] According to the present invention, in S1, the relative motion model between the aircraft and the target can be expressed as:

[0068]

[0069]

[0070] a R =cos(θ) M -θR )a M -cos(θ T -θ R )a T (3)

[0071] Where, θ R θ represents the relative track angle between the aircraft and the target. M θ represents the flight path angle of the aircraft. T The target's trajectory angle, k = V T / V M ;

[0072] V R V represents the relative velocity between the aircraft and the target. M V represents the speed of the aircraft. T Indicates the target's speed;

[0073] a R a represents the relative acceleration between the aircraft and the target. M a represents the acceleration of an aircraft perpendicular to its velocity. T This represents the acceleration of a target perpendicular to its velocity, such as... Figure 2 , 3 As shown.

[0074] Furthermore, the kinematic model of the aircraft is represented as follows:

[0075]

[0076] Where r represents the relative distance between the aircraft and the target, q represents the line-of-sight angle between the target and the aircraft, t represents time, and η R This represents the virtual perspective of the aircraft and the target, specifically the difference between the aircraft's trajectory angle and the target's line-of-sight angle in its relative coordinate system, and has V. R =V M -V T a R =a M -a T .

[0077] Because the target is treated as a stationary target, the number of parameters in the aircraft kinematic model of this invention is greatly simplified compared to traditional guidance methods. The solution process of the kinematic model is also simpler, which further reduces the computing power requirements of the guidance chip and improves the calculation speed when obtaining the aircraft acceleration.

[0078] Furthermore, in the kinematic model of the aircraft, through the virtual perspective η R As one of the constraints of the model, it ensures that the aircraft does not lose sight of the target during flight, thus improving the success rate of interception.

[0079] According to the present invention, the relative acceleration of the aircraft to the target can be obtained through the relative motion model of the aircraft and the target and the dynamic model of the aircraft. Specifically, in S2, the relative acceleration of the aircraft to the target can be expressed as:

[0080]

[0081]

[0082]

[0083] r go * =V R (T d -t)

[0084]

[0085] Among them, T d Let t be the expected attack time of the aircraft, m and n be the guidance coefficients, ε represent the remaining flight distance error, and a be the guidance coefficients. p r go * , This is an intermediate parameter.

[0086] Preferably, 4 > m, n > 0.

[0087] Traditional guidance methods mostly only obtain the target's position and use that position as a reference to derive the aircraft's own guidance law. This guidance method does not take into account the target's actual flight state and is an independent guidance method for the aircraft itself. When the target speed is high or the target speed direction differs greatly from the aircraft's flight direction, the aircraft is prone to losing the target, resulting in interception failure. In this invention, the acceleration of the aircraft relative to the target is obtained. During the entire process of the aircraft intercepting the target, the relative acceleration enables the aircraft to follow the target in a coordinated manner, thus solving the drawbacks of traditional guidance methods.

[0088] Furthermore, the form of the aircraft's acceleration relative to the target makes the miss distance and overall flight time controllable, thus enabling multiple aircraft to reach the target location simultaneously at the desired time.

[0089] Based on the relative acceleration of the aircraft to the target obtained in step S2, the relative acceleration can be decoupled into guidance commands for the aircraft using a relative motion model. Specifically, this can be obtained from formula (3):

[0090]

[0091] Substituting formula (5) into formula (6) yields:

[0092]

[0093] In this invention, the number of parameters required in the guidance command decreases sequentially when intercepting maneuvering targets, uniformly moving targets, and stationary targets. Based on the characteristics of this guidance law, the inventors adopted different guidance commands for different target states. While achieving good guidance accuracy, this also reduces the amount of calculation and improves the calculation speed.

[0094] According to the present invention, in S3, the target flight state refers to the target being in a state of being stationary, moving at a constant speed, or moving at a variable speed.

[0095] When the target is stationary, the aircraft's guidance commands are:

[0096]

[0097] When the target is in uniform motion, the guidance command for the aircraft is:

[0098]

[0099] When the target is in a state of variable speed motion, the guidance command of the aircraft is:

[0100]

[0101] In this invention, there is no particular limitation on the method of obtaining the target state. Visual judgment can be made by a seeker, infrared ranging judgment can be made, or radar judgment can be made, as long as the target state can be judged.

[0102] Furthermore, unlike traditional guidance methods, the guidance commands provided by this invention do not require estimation of the remaining flight time of the aircraft. The information required for the guidance commands can be directly measured by airborne radar or seeker, thereby improving the interception accuracy.

[0103] In a preferred embodiment, a threshold is also set for the remaining flight distance error. When the remaining flight distance error is less than the threshold, the guidance command adjustment in step S3 is adjusted.

[0104] By setting a threshold, the computational complexity of the guidance law at the guidance terminal is simplified, and the command frequency at the guidance terminal is increased, thereby further improving the interception success rate and increasing the guidance robustness and engineering applicability.

[0105] In this invention, the remaining flight distance error is obtained based on the aircraft's detection of the target position, specifically, by the following formula:

[0106]

[0107] r go * =V R (T d -t)

[0108]

[0109] Among them, V R , r, η R n and T are obtained through measurements by the seeker or radar. d t is the preset value, and t is the flight time of the aircraft.

[0110] The adjusted guidance command is as follows:

[0111] When the target is stationary, the guidance command for the aircraft is:

[0112]

[0113] When the target is in uniform motion, the guidance command of the aircraft is:

[0114]

[0115] When the target is in a state of variable speed motion, the guidance command of the aircraft is:

[0116]

[0117] In this invention, the aforementioned guidance command also ensures that when the aircraft encounters the target, the acceleration of the aircraft is not greater than the acceleration of the target, thus avoiding the saturation of the aircraft's terminal acceleration and providing conditions for intercepting maneuvering targets.

[0118] In a preferred embodiment, the threshold is set to V. M *0.01(s), where s represents seconds.

[0119] Example

[0120] Example 1

[0121] The initial positions of the aircraft and the target were determined through simulation experiments, as shown in Table 1.

[0122] Table 1 Initial Position Parameter Settings

[0123]

[0124] The target performs a sinusoidal maneuver with an initial position of (-6500m, -7500m), an initial track angle of -20°, a speed of 50m / s, and an acceleration of 10sin(πt / 8)m / s². 2The aircraft speed is a constant 300m / s, the desired guidance time is 50s, and the amplitude of the aircraft guidance command is limited to within 10g.

[0125] The aircraft uses the following steps for guidance:

[0126] S1. Based on the relative motion model between the aircraft and the target, design the kinematic model of the aircraft under the relative motion model;

[0127] S2. Obtain the aircraft's acceleration relative to the target;

[0128] S3. Obtain guidance commands for the aircraft based on the target's flight status.

[0129] In S1, the relative motion model between the aircraft and the target can be represented as:

[0130]

[0131]

[0132] a R =cos(θ) M -θ R )a M -cos(θ T -θ R )a T

[0133] The kinematic model of the aircraft is represented as follows:

[0134]

[0135] Where r represents the relative distance between the aircraft and the target, q represents the line-of-sight angle between the target and the aircraft, t represents time, and η R Represents the virtual perspective of the aircraft and the target, and has V R =V M -V T a R =a M -a T .

[0136] In S2, the acceleration of the aircraft relative to the target is expressed as:

[0137]

[0138]

[0139]

[0140] r go * =V R(T d -t)

[0141]

[0142] Among them, T d Let t be the expected attack time of the aircraft, m and n be the guidance coefficients, ε represent the remaining flight distance error, and a be the guidance coefficients. p r go * , This is an intermediate parameter.

[0143] Since the target is in a state of variable speed motion, the initial guidance commands for the aircraft are:

[0144]

[0145] A threshold is set for the remaining flight distance error. When the remaining flight distance error is less than the threshold, the aircraft's guidance command is...

[0146]

[0147] The threshold is set to 3 meters.

[0148] Example 2

[0149] The same experiment as in Example 1 was conducted, except that only one aircraft was used, and the initial settings of the aircraft and the target are shown in Table 2:

[0150]

[0151] The target accelerations were set to aT1 = 0.3g sin(πt / 30) and aT2 = 0.5g sin(πt / 30), respectively. Two simulation experiments were conducted, and the expected guidance time was set to 80s in both simulation experiments.

[0152] Comparative Example 1

[0153] The simulation experiment was conducted with the initial positions of the aircraft and the target being the same as in Example 1, and the aircraft acceleration was performed using Enhanced Proportional Guidance (APNG).

[0154] For details on Enhanced Proportional Guidance (APNG), please refer to the following literature: PAUL Z. Tactical and strategic missile guidance. 6th ed. Virginia: AIAA Inc.; 2012. pp. 541, 569.

[0155] The flight times of aircraft 1, 2, 3, and 4 using APNG are 39.86s, 28.56s, 24.54s, and 36.81s, respectively.

[0156] Comparative Example 2

[0157] The simulation experiment was conducted with the initial positions of the aircraft and the target being the same as in Example 2. The aircraft acceleration was performed using the WTG (without explicit time-to-go estimation guidance) guidance law with attack time constraints.

[0158] For details on the WTG guidance law, please refer to the literature H. Kim, D. Cho and HJ Kim, Sliding Mode Guidance Law for Impact Time Control Without Explicit Time-to-Go Estimation, IEEE Transactions on Aerospace and Electronic Systems 2019; 55(1): 236-250.

[0159] Experimental Example 1

[0160] The simulation results of Example 1 are compared with those of Comparative Example 1, and the results are as follows: Figures 4-5 As shown.

[0161] in, Figure 4 The trajectories of the aircraft and the target in Example 1 and Comparative Example 1 are shown, from... Figure 4 It can be seen that when the expected attack time is 50s, the trajectory of the aircraft in Example 1 is more curved than that in Comparative Example 1, making it more difficult for the target to identify the aircraft's interception intention. Especially when there are multiple targets, it can greatly avoid the target from making interference evasion actions. At the same time, it can be seen from the figure that for maneuvering targets, four aircraft with different initial positions can hit the target simultaneously with the expected attack time and meet the constraints of the terminal virtual viewpoint, showing good salvo attack guidance performance.

[0162] Figure 5 The figure shows the acceleration of the aircraft in Example 1. As can be seen from the figure, when the aircraft approaches the target, the acceleration of different aircraft approaches 0, which avoids the saturation of the terminal acceleration of the aircraft and provides room for response to the situation of the target suddenly escaping with a large acceleration.

[0163] Experiment Example 2

[0164] Comparing the results of Example 2 and Comparative Example 2, where the target is a T1During acceleration maneuvers, the flight time of the aircraft in Example 2 was 80.21s, and the flight time of Comparative Example 2 was 79.69s; when the target moves at an acceleration of a... T2 During acceleration maneuvers, the flight time of the aircraft in Example 2 was 80.17s, while that in Comparative Example 2 was 79.54s. Example 2 demonstrates more precise flight time control compared to Comparative Example 2, significantly improving the success rate of target interception.

[0165] Figure 6 The comparison results of the acceleration commands in Example 2 and Comparative Example 2 are shown when the target moves with aT1 = 0.3g sin(πt / 30). Figure 7 The figure shows a comparison of the acceleration commands of Example 2 and Comparative Example 2 when the target moves at aT2 = 0.5g sin(πt / 30). As can be seen from the figure, the acceleration of Example 2 is much smaller than that of Comparative Example 2 in the initial stage. Although there is a small increase in the terminal phase, it quickly converges to a smaller value, avoiding terminal acceleration command saturation. However, Comparative Example 2 has a larger acceleration command in the early stages of guidance and diverges to the given overload limit value at the terminal phase. Therefore, Example 2 exhibits better guidance performance than Comparative Example 2, and places lower load requirements on the aircraft during interception.

[0166] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this invention, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0167] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0168] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A method for cooperative guidance of aircraft formations, characterized in that, Includes the following steps: S1. Based on the relative motion model between the aircraft and the target, design the kinematic model of the aircraft under the relative motion model; S2. Obtain the aircraft's acceleration relative to the target; S3. Obtain guidance commands for the aircraft based on the target's flight status; In the relative motion model between the aircraft and the target, the target is set to be in a relatively stationary state; In S1, the relative motion model between the aircraft and the target can be represented as: ， ， ， in, Indicates the relative track angle between the aircraft and the target. Indicates the flight path angle of the aircraft. Indicates the target's trajectory angle. ; Indicates the relative speed between the aircraft and the target. Indicates the speed of the aircraft. Indicates the target's speed; Represents the relative acceleration between the aircraft and the target. This represents the acceleration of an aircraft perpendicular to its velocity. This represents the acceleration of the target perpendicular to its velocity. The kinematic model of the aircraft is represented as follows: ， in, Indicates the relative distance between the aircraft and the target. q This indicates the line-of-sight angle of the target relative to the aircraft. t Indicates time, This represents the virtual perspective of the aircraft and the target, specifically the difference between the aircraft's trajectory angle and the target's line-of-sight angle in its relative coordinate system to the target, and has... , ; In S2, the acceleration of the aircraft relative to the target can be expressed as: ， ， ， ， ， in, The expected attack time for the aircraft. For time, The guidance coefficient, Indicates the remaining flight distance error. This is an intermediate parameter.

2. The aircraft formation cooperative guidance method according to claim 1, characterized in that, There are multiple aircraft, and the initial positions of the multiple aircraft are different.

3. The aircraft formation cooperative guidance method according to claim 1, characterized in that, The target flight state refers to whether the target is stationary, moving at a constant speed, or moving at a variable speed. When the target is stationary, the aircraft's guidance commands are: ， When the target is in uniform motion, the guidance command for the aircraft is: ， When the target is in a state of variable speed motion, the guidance command of the aircraft is: 。 4. The aircraft formation cooperative guidance method according to claim 3, characterized in that, A threshold is set for the remaining flight distance error. When the remaining flight distance error is less than the threshold, the guidance command in step S3 is adjusted to: When the target is stationary, the guidance command for the aircraft is: ， When the target is in uniform motion, the guidance command of the aircraft is: ， When the target is in a state of variable speed motion, the guidance command of the aircraft is: 。 5. The aircraft formation cooperative guidance method according to claim 4, characterized in that, The threshold is set to , s It represents seconds.

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