A target identification method based on supersonic aircraft derivative effect

Abstract

The application discloses a target identification method based on a supersonic aircraft derivative effect, and comprises the following steps: S1, establishing a sound blast cloud mathematical model; S2, simulating and constructing a simulation sound blast cloud according to the sound blast cloud mathematical model; S3, acquiring laser radar echo features of supersonic aircrafts under different flight postures; and S4, analyzing the laser radar echo features and identifying the supersonic aircrafts. The application breaks through the inherent method of identifying a target based on the reflection of the target itself, and provides a new idea for future aircraft detection.

Description

Technical Field

[0001] This invention relates to the field of optical scattering and transmission simulation testing technology, and in particular to a feature tracking and identification method based on the derivative effects of supersonic aircraft. Background Technology

[0002] Currently, the identification and detection methods for supersonic aircraft are mainly concentrated in the fields of traditional radar detection and imaging. However, with the gradual improvement of the design level of supersonic aircraft, traditional detection and identification technologies no longer have the advantage of detecting supersonic aircraft.

[0003] Laser detection and identification technology for conventional speed aircraft targets is mainly based on the reflection and scattering of the target itself. When a target aircraft flies at high speed in the atmosphere, the target body will rub against the surrounding atmosphere, causing severe disturbance to the atmosphere; a shock wave flow field with high temperature and high pressure will form around the target body, forming a diffuse sonic boom cloud around the wings, thereby changing the refraction, scattering and absorption characteristics of the surrounding atmosphere, causing phenomena such as deflection and multiple scattering of the detection light. Summary of the Invention

[0004] The purpose of this invention is to propose a target recognition method based on the derivative effects of supersonic aircraft. To address the problems in the background art, this invention achieves this through the following technical solution:

[0005] A target identification method based on the derivative effect of a supersonic aircraft includes: step S1, establishing a mathematical model of a sonic boom cloud; step S2, simulating and constructing a simulated sonic boom cloud based on the mathematical model of the sonic boom cloud; step S3, obtaining the lidar echo characteristics of the supersonic aircraft under different flight attitudes; and step S4, analyzing the lidar echo characteristics to identify the supersonic aircraft.

[0006] Optionally, step S1 includes: Step S11, based on the actual sonic boom cloud generation mechanism, performing numerical simulation of the flow field around the fuselage of the supersonic vehicle to obtain the flow field parameter distribution around the fuselage of the supersonic vehicle. Step S12, calculating the first saturated water vapor content around the fuselage of the supersonic vehicle based on the flow field parameter distribution around the fuselage of the supersonic vehicle. Step S13, calculating the second saturated water vapor content in the atmospheric environment based on atmospheric environmental parameters, thereby obtaining the liquid water content distribution precipitated around the fuselage of the supersonic vehicle. Step S14, calculating the droplet size spectrum distribution and droplet number distribution in the sonic boom cloud based on the liquid water content distribution and the first saturated water vapor content, obtaining the modeling result of the sonic boom cloud.

[0007] Optionally, the flow field parameter distribution around the fuselage of the supersonic vehicle includes: the temperature around the fuselage of the supersonic vehicle and the pressure around the fuselage of the supersonic vehicle.

[0008] Optionally, step S2 includes: establishing a sonic boom cloud simulation device, and using the sonic boom cloud simulation device to generate the simulated sonic boom cloud. The sonic boom cloud simulation device includes: a circular water supply pipe; several nozzles spaced circumferentially on the circular water supply pipe; a water tank storing water; a water supply pipe; and a high-pressure pump system, one end of which is connected to the water tank, and the other end of which is connected to the circular water supply pipe through the water supply pipe. The high-pressure pump system is used to pressurize the water and deliver it into the circular water supply pipe. The multiple nozzles are used to atomize the water in the circular water supply pipe and spray it outward, forming a circular fan-shaped cloud environment around the circular output pipe; the circular fan-shaped cloud environment is the simulated sonic boom cloud. By adjusting the pressure applied to the water by the high-pressure pump system and adjusting the opening of the nozzles, the rain and fog concentration of the simulated sonic boom cloud can be changed. By placing the aircraft model in the circular fan-shaped cloud environment, a realistic simulation scene of the aircraft's sonic boom cloud is formed. A visibility meter is used to monitor the visibility of the simulated sonic boom cloud in real time; a particle size distribution analyzer is used to obtain the real-time particle size distribution of the simulated sonic boom cloud.

[0009] Optionally, the high-pressure pump system is a brass plunger high-pressure pump system.

[0010] Optionally, step S3 includes: Step S31, measuring the background signal. Step S32, acquiring the echo signal of the aircraft model in the atmospheric environment. The aircraft model is suspended in the air at a certain attitude, and the first target echo signal of the aircraft model in the atmospheric environment at each azimuth angle is acquired. Step S33, activating the sonic boom cloud simulation device to generate the simulated sonic boom cloud; acquiring the second target echo signal of the aircraft model in the simulated sonic boom cloud at each azimuth angle. Step S34, measuring the background signal again. Step S35, based on the background signal measured in steps S31 and S34, subtracting the background signal from the first target echo signal and the second target echo signal. Step S36, comparing the intensity of the first target echo signal and the second target echo signal, the delay time of the first target echo signal and the second target echo signal, and the first target echo signal and the second target echo signal in step S35, to extract the lidar echo features under the simulated sonic boom cloud condition.

[0011] Optionally, step S33 includes: controlling the sonic boom cloud simulation device to adjust the water content and particle size in the simulated sonic boom cloud to be on the same order of magnitude as the water content and particle size in the real sonic boom cloud.

[0012] Optionally, step S33 further includes: quantitatively controlling the rain and fog concentration in the simulated sonic boom cloud: using the particle size analyzer to monitor the rain and fog concentration in the simulated sonic boom cloud in real time, obtaining the particle size and size in the simulated sonic boom cloud, and adjusting the pressure applied to the water by the high-pressure pump system in the sonic boom cloud simulation device and adjusting the opening of the nozzle according to the particle size and size of the real sonic boom cloud, so as to adjust the rain and fog concentration of the simulated sonic boom cloud.

[0013] Optionally, step S4 includes: identifying the aircraft model by comparing the differences in the lidar echo characteristics under the condition of having the simulated sonic boom cloud and under the condition of not having the simulated sonic boom cloud.

[0014] Optionally, the differences in the lidar echo characteristics include: differences in echo peak value, differences in echo broadening, and differences in echo waveform.

[0015] This invention breaks through the traditional approach of identifying aircraft based on their own reflections, and conducts simulated detection of aircraft-derived effects to achieve feature recognition of supersonic aircraft, providing a new approach for future aircraft detection. Attached Figure Description

[0016] Figure 1 A flowchart illustrating a target recognition method based on the derivative effect of a supersonic aircraft, provided in an embodiment of the present invention;

[0017] Figure 2 A flowchart of mathematical modeling of a sonic boom cloud provided in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of a sonic boom cloud simulation device provided in an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of aircraft lidar echo feature acquisition according to an embodiment of the present invention;

[0020] Figure 5 A flowchart of a method for acquiring the echo features of a spacecraft lidar according to an embodiment of the present invention;

[0021] Figure 6 This is a graph showing the measurement results of the presence and absence of sonic boom cloud echo signal intensity, provided in an embodiment of the present invention. Detailed Implementation

[0022] The target identification method based on the derivative effect of a supersonic aircraft, as proposed in this invention, will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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 the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction 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.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] Figure 1 This is a flowchart illustrating a target recognition method based on the derivative effects of a supersonic aircraft, as provided in an embodiment of the present invention. Figure 1 As shown, this embodiment provides a target identification method based on the derivative effect of a supersonic aircraft, including: Step S1, establishing a mathematical model of a sonic boom cloud; Step S2, simulating and constructing a simulated sonic boom cloud based on the mathematical model; Step S3, acquiring the lidar echo characteristics of the supersonic aircraft under different flight attitudes; Step S4, analyzing the lidar echo characteristics to identify the supersonic aircraft.

[0028] This invention addresses the derivative effects of supersonic aircraft targets. It simulates and measures the lidar echoes of sonic boom clouds from different aircraft, and verifies the results using a simulation model. By acquiring lidar echo measurement data of sonic boom clouds from different aircraft, and then comparing the echo differences under different sonic boom cloud conditions, target identification is achieved. This involves establishing a mathematical model of the aircraft's sonic boom cloud; simulating a realistic sonic boom cloud scenario based on the model; extracting lidar echo characteristics of the aircraft under different flight attitudes; and identifying the aircraft based on these echo characteristics. This method provides a new approach for future aircraft detection.

[0029] like Figure 2 As shown, step S1 includes:

[0030] Step S11: Based on the actual sonic boom cloud generation mechanism, numerical simulation is performed on the flow field around the fuselage of the supersonic vehicle to obtain the flow field parameter distribution around the fuselage of the supersonic vehicle. The flow field parameter distribution around the fuselage of the supersonic vehicle includes: the temperature around the fuselage of the supersonic vehicle and the pressure around the fuselage of the supersonic vehicle.

[0031] Step S12: Calculate the first saturated water vapor content around the fuselage of the supersonic aircraft based on the distribution of flow field parameters around the fuselage.

[0032] Step S13: Calculate the second saturated water vapor content in the atmospheric environment based on atmospheric environmental parameters, and then obtain the distribution of liquid water content precipitated around the fuselage of the supersonic aircraft.

[0033] Step S14: Based on the liquid water content distribution (droplet distribution model) and the first saturated water vapor content, calculate the droplet size distribution and droplet number distribution in the sonic boom cloud to obtain the modeling result of the sonic boom cloud.

[0034] For example, this embodiment proposes a method for mathematically modeling sonic boom clouds based on atmospheric water content and aircraft flow field analysis. The sonic boom cloud model obtained by this mathematical modeling method mainly provides parameter input for subsequent establishment of a realistic sonic boom cloud test environment. Specifically, based on the sonic boom cloud generation mechanism, the flow field around the aircraft fuselage is numerically simulated; further, the distribution of flow field parameters such as temperature and pressure around the fuselage is obtained, and then the saturated water vapor content around the fuselage is calculated; further, the water vapor content in the atmospheric environment is calculated based on atmospheric environmental parameters, and the distribution of liquid water content precipitated around the fuselage is obtained; further, based on the droplet distribution model, the droplet diameter spectrum distribution and droplet number distribution in the sonic boom cloud are calculated, and the sonic boom cloud modeling result is obtained. Specifically, the sonic boom cloud model can obtain the distribution of specific parameters such as particle size and shape of the sonic boom cloud.

[0035] like Figure 3As shown, step S2 includes: establishing a sonic boom cloud simulation device, and using the sonic boom cloud simulation device to generate the simulated sonic boom cloud; the sonic boom cloud simulation device includes: a circular water supply pipe 2, several nozzles 5 arranged circumferentially on the circular water supply pipe 2, a water tank 3 containing water; a water supply pipe, a high-pressure pump system 4, one end of which is connected to the water tank, and the other end of which is connected to the circular water supply pipe 2 through the water supply pipe; the high-pressure pump system 4 is used to pressurize the water and deliver it into the circular water supply pipe 2, and the multiple nozzles 5 are used to atomize the water in the circular water supply pipe 2. The water is sprayed outwards, forming a circular fan-shaped cloud environment around the circular output pipe; this circular fan-shaped cloud environment is the simulated sonic boom cloud 8. The rain and fog concentration of the simulated sonic boom cloud 8 is changed by adjusting the pressure applied to the water by the high-pressure pump system 4 and adjusting the opening of the nozzle 5. Placing the aircraft model 6 within this circular fan-shaped cloud environment creates a realistic simulation scene of the aircraft's sonic boom cloud. A visibility meter is used to monitor the visibility of the simulated sonic boom cloud 8 in real time; a particle size analyzer is used to obtain the real-time particle size distribution of the simulated sonic boom cloud 8. The high-pressure pump system 4 is a brass plunger high-pressure pump system. Simulating a realistic sonic boom cloud scene allows for quantitative control of the sonic boom cloud, perfectly reproducing the real sonic boom cloud scene.

[0036] For example, this embodiment proposes a method for simulating and constructing a realistic sonic boom cloud scene. Based on the modeling results of the aircraft and the sonic boom cloud, corresponding aircraft models and sonic boom cloud models are designed and manufactured. Specifically, the construction of the realistic sonic boom cloud 1 simulation scene will use a combination of circular water pipes 2 connected to multiple nozzles 5 to form a circular fan-shaped cloud environment. Further, connecting the circular water pipes to the aircraft model forms a realistic simulation scene of the aircraft's sonic boom cloud. Specifically, to achieve the controllability of the sonic boom cloud simulation environment, the simulation system will use a brass plunger high-pressure pump system 4 to pressurize and atomize the water in the water tank 3 through electricity, achieving cloud and fog conversion. The system pressure and nozzles are adjustable, thus allowing the concentration of the simulated sonic boom cloud to be changed. To achieve the quantification of the sonic boom cloud simulation environment, the simulation environment will be equipped with a visibility meter and a particle size distribution analyzer to obtain the real-time particle size distribution of the sonic boom cloud, ensuring consistency with the particle size distribution of the simulation model.

[0037] like Figure 5 As shown, step S3 includes:

[0038] Step S31: Measure the background signal.

[0039] Step S32: Obtain the echo signal of the aircraft model in the atmospheric environment. For example... Figure 4As shown, the aircraft model 6 is suspended in the air in a certain attitude, and the first target echo signal of the aircraft model 6 in each azimuth angle is obtained by illuminating it with lidar 7.

[0040] Step S33: Activate the sonic boom cloud simulation device to generate the simulated sonic boom cloud 8; irradiate with lidar 7 to obtain the second target echo signal of the aircraft model in the simulated sonic boom cloud 8 at each azimuth angle. Control the sonic boom cloud simulation device to adjust the water content and particle size in the simulated sonic boom cloud 8 to be on the same order of magnitude as the water content and particle size in the real sonic boom cloud; quantitatively control the rain and fog concentration in the simulated sonic boom cloud 8: use a raindrop spectrometer and the particle size analyzer (particle size analyzer) to monitor the rain and fog concentration in the simulated sonic boom cloud in real time to obtain the particle size and size in the simulated sonic boom cloud 8; adjust the pressure applied to the water by the high-pressure pump system 4 in the sonic boom cloud simulation device and adjust the opening of the nozzle 5 according to the particle size and size values ​​of the real sonic boom cloud 8 to adjust the rain and fog concentration of the simulated sonic boom cloud 8.

[0041] Step S34: Measure the background signal again.

[0042] Step S35: Based on the background signals measured in steps S31 and S34, the background signal is subtracted from the first target echo signal and the second target echo signal.

[0043] In steps S36 and S35, the intensity of the first target echo signal and the second target echo signal, the delay time of the first target echo signal and the second target echo signal, and the first target echo signal and the second target echo signal are compared to extract the lidar echo features under the simulated sonic boom cloud condition.

[0044] For example, this embodiment proposes a method for acquiring lidar echo features of an aircraft under different flight attitudes. Figure 5 As shown, the specific steps are as follows:

[0045] Acquiring atmospheric target echo signals: Suspend the target in the air at a certain attitude and acquire the echo signals of the target at each azimuth angle. Controlling the simulated sonic boom cloud concentration to ensure that the water content and particle size are on the same order of magnitude as the sonic boom cloud: Quantitatively control the rain and fog concentration in the experimental environment, using a raindrop spectrometer and particle size analyzer for real-time monitoring. Acquiring target echo signals in the simulated sonic boom cloud environment, such as... Figure 5 As shown. Background subtraction: Due to the need to measure the echo from different angles of the aircraft, the measurement time is relatively long. Therefore, the sunlight energy changes significantly during the measurement process. Background signals need to be measured before and after the experiment to reduce background interference. By comparing the echo signal intensity, echo signal delay time, and echo signal waveform with and without sonic boom clouds, as shown... Figure 5 As shown, the echo features of the aircraft in the presence of sonic boom clouds are extracted for target identification.

[0046] Figure 6 The measurement results of the presence and absence of sonic boom cloud echo signal intensity provided in this embodiment are shown in the figure. The data in the figure is a comparison of the echo signals of the first target and the second target under a certain state. It can be seen that there are obvious differences in their signal intensity, echo signal time delay, and echo signal waveform, thereby identifying the aircraft model.

[0047] In summary, this embodiment establishes a mathematical model of a sonic boom cloud for an aircraft; simulates and constructs a realistic sonic boom cloud scenario based on the model; extracts the lidar echo features of the aircraft under different flight attitudes; and identifies the aircraft based on these echo features. This method breaks through the traditional approach of identifying aircraft based on their own reflection, conducts simulated detection of aircraft-derived effects, and achieves feature identification of supersonic aircraft, providing a new approach for future aircraft detection.

[0048] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A target recognition method based on the derivative effect of supersonic aircraft, characterized in that, include: Step S1: Establish a mathematical model of the sonic boom cloud; Step S2: Based on the sonic boom cloud mathematical model, simulate and construct a sonic boom cloud; Step S3: Obtain the lidar echo characteristics of the supersonic vehicle under different flight attitudes; Step S4: Analyze the characteristics of the lidar echo to identify the supersonic aircraft; Step S1 includes: Step S11: Based on the actual sonic boom cloud generation mechanism, numerical simulation is performed on the flow field around the fuselage of the supersonic vehicle to obtain the flow field parameter distribution around the fuselage of the supersonic vehicle. Step S12: Calculate the first saturated water vapor content around the fuselage of the supersonic vehicle based on the distribution of flow field parameters around the fuselage. Step S13: Calculate the second saturated water vapor content in the atmosphere based on atmospheric environmental parameters, and then obtain the distribution of liquid water content precipitated around the fuselage of the supersonic aircraft. Step S14: Based on the liquid water content distribution and the first saturated water vapor content, calculate the droplet size distribution and droplet number distribution in the sonic boom cloud to obtain the modeling result of the sonic boom cloud; Step S3 includes: Step S31: Measure the background signal; Step S32: Acquire the echo signal of the aircraft model in the atmospheric environment; The aircraft model is suspended in the air in a certain attitude, and the first target echo signal of the aircraft model in the atmospheric environment at each azimuth angle is obtained. Step S33: Activate the sonic boom cloud simulation device to generate the simulated sonic boom cloud; acquire the second target echo signal of the aircraft model in the simulated sonic boom cloud at each azimuth angle; Step S34: Measure the background signal again; Step S35: Based on the background signals measured in steps S31 and S34, the background signal is subtracted from the first target echo signal and the second target echo signal; In steps S36 and S35, the intensity of the first target echo signal and the second target echo signal, the delay time of the first target echo signal and the second target echo signal, and the first target echo signal and the second target echo signal are compared to extract the lidar echo features under the simulated sonic boom cloud condition. Step S4 includes: The aircraft model is identified by comparing the differences in the lidar echo characteristics under conditions with and without the simulated sonic boom cloud.

2. The target recognition method based on the derivative effect of supersonic aircraft according to claim 1, characterized in that, The flow field parameter distribution around the fuselage of the supersonic aircraft includes: the temperature around the fuselage of the supersonic aircraft and the pressure around the fuselage of the supersonic aircraft.

3. The target recognition method based on the derivative effect of supersonic aircraft according to claim 1, characterized in that, Step S2 includes: establishing a sonic boom cloud simulation device, and using the sonic boom cloud simulation device to generate the simulated sonic boom cloud; the sonic boom cloud simulation device includes: Circular water supply pipe; Several nozzles are arranged circumferentially on the circular water supply pipe; A water tank, which stores water. Water pipeline; A high-pressure pump system, one end of which is connected to the water tank, and the other end of which is connected to the circular water supply pipe through the water supply pipe; The high-pressure pump system is used to pressurize the water and deliver it into the circular water supply pipe. The multiple nozzles are used to atomize the water in the circular water supply pipe and spray it outward, forming a circular fan-shaped cloud environment around the circular output pipe. The circular fan-shaped cloud environment is a simulated sonic boom cloud. The concentration of rain and fog in the simulated sonic boom cloud can be changed by adjusting the pressure applied to the water by the high-pressure pump system and by adjusting the opening of the nozzle. By placing the aircraft model within the cloud and fog environment of the circular fan, a realistic simulation scene of the aircraft's sonic boom cloud is created. A visibility meter is used to monitor the visibility of the simulated sonic boom cloud in real time. A particle size distribution analyzer is used to obtain the real-time particle size distribution of the simulated sonic boom cloud.

4. The target recognition method based on the derivative effect of supersonic aircraft according to claim 3, characterized in that, The high-pressure pump system is a brass plunger high-pressure pump system.

5. The target recognition method based on the derivative effect of supersonic aircraft according to claim 1, characterized in that, Step S33 includes: The sonic boom cloud simulation device is controlled to adjust the water content and particle size in the simulated sonic boom cloud to be on the same order of magnitude as those in the real sonic boom cloud.

6. The target recognition method based on the derivative effect of a supersonic aircraft according to claim 3, characterized in that, Step S33 further includes: Quantitative control of rain and fog concentration in the simulated sonic boom cloud: The particle size analyzer is used to monitor the rain and fog concentration in the simulated sonic boom cloud in real time to obtain the particle size and size in the simulated sonic boom cloud. Based on the particle size and size of the real sonic boom cloud, the pressure applied to the water by the high-pressure pump system in the sonic boom cloud simulation device and the opening of the nozzle are adjusted to regulate the rain and fog concentration of the simulated sonic boom cloud.

7. The target recognition method based on the derivative effect of supersonic aircraft according to claim 1, characterized in that, The differences in the lidar echo characteristics include: differences in echo peak value, differences in echo broadening, and differences in echo waveform.

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