Aircraft detection spectrum optimal selection method based on physical mechanism

Abstract

The invention discloses an aircraft detection spectrum optimization method based on a physical mechanism, and the method comprises the steps: calculating the spectral radiation intensity of the jet flame of an engine of an aircraft at different flight heights based on the radiation generation principle of the jet flame of the engine of the aircraft; based on the distribution condition of the spectral radiation intensity of the engine jet flame of the aircraft at different flight heights, a detection spectrum section interval is determined, and the detection spectrum section interval is divided into a plurality of detection spectrum sections; calculating target and background radiation contrast ratios corresponding to different flight heights under each detection spectrum section in combination with detector parameters; and on the basis of the target and background radiation contrast corresponding to different flight heights under each detection spectrum band, the contrast of each detection spectrum band is calculated through an arithmetic average method, so that the detection spectrum bands are optimized.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, and in particular to a method for optimizing the detection spectrum of aircraft based on physical mechanisms. Background Technology

[0002] Aircraft engines are the power source of aircraft, and their exhaust radiation is an important source of information for optical detection. Selecting an appropriate detection spectrum is beneficial for highlighting the contrast between the target and the background radiation, and has wide application value and significance in fields such as aerospace launch monitoring, engine operating status assessment, and fault diagnosis.

[0003] However, current research on optimizing the detection spectrum for aircraft often focuses on payload design, primarily by studying the contrast between the radiation characteristics of the target and the background in different spectral bands, and calculating the contrast between the target and the radiation in multiple spectral bands under a fixed state. This approach fails to adequately establish optimal evaluation criteria from the perspective of physical mechanisms, i.e., radiation principles, and does not consider the impact of the aircraft's flight altitude on the contrast between the target and the background radiation.

[0004] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a physical mechanism-based method for optimizing the detection spectrum of aircraft. This addresses the current practice of optimizing detection spectrum for aircraft by considering only the payload design perspective and neglecting the physical mechanisms, i.e., the radiation principle. Based on the principle of emission radiation from aircraft engine exhaust spectra, this method divides the detection spectrum into segments and calculates the contrast of each segment at different flight altitudes to obtain the corresponding contrast ratio. This contrast ratio serves as an evaluation index for optimizing the detection spectrum, thus improving detection performance during aircraft launch monitoring.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a method for optimizing the detection spectrum of a spacecraft based on physical mechanisms, comprising: Based on the radiation generation principle of aircraft engine exhaust, the spectral radiation intensity of the aircraft engine exhaust at different flight altitudes is calculated. Based on the distribution of the spectral radiation intensity of the engine exhaust at different flight altitudes, the detection spectral range is determined, and the detection spectral range is divided into multiple detection spectral bands. Based on the detector parameters, the target-background radiation contrast at different flight altitudes under each detection spectrum band is calculated; Based on the contrast between target and background radiation at different flight altitudes in each detection spectral band, the contrast of each detection spectral band is calculated using the arithmetic mean method to optimize the detection spectral band.

[0007] Optionally, the calculation of the spectral radiation intensity of the aircraft's engine exhaust at different flight altitudes, based on the radiation generation principle of the aircraft's engine exhaust, includes: Determine the aircraft's technical parameters and flight environment parameters; Based on the technical parameters and flight environment parameters, hydrodynamic calculations are performed to obtain the flow field distribution of the aircraft engine exhaust flame; Based on the aforementioned flow field distribution and combined with the narrowband K-distribution technology database, the spectral radiation intensity of the engine exhaust plume of the aircraft at different flight altitudes is calculated.

[0008] Optionally, the technical parameters include at least: engine model, engine nozzle size, fuel type, fuel ratio, and nozzle expansion ratio; The flight environment parameters include at least: flight altitude, flight speed, and atmospheric environmental pressure and temperature corresponding to the flight altitude.

[0009] Optionally, the flow field distribution includes: flow field temperature distribution, flow field pressure distribution, and flow field component distribution.

[0010] Optionally, determining the detection spectral range based on the distribution of engine exhaust spectral radiation intensity at different flight altitudes, and dividing the detection spectral range into multiple detection spectral bands with the same bandwidth, includes: Based on the distribution of the spectral radiation intensity of the engine exhaust at different flight altitudes, in the shortwave band, the wavelength position where the peak of the spectral radiation intensity is located is taken as the center position, and the spectrum is extended to the shortwave and longwave directions respectively to form the detection spectrum interval, and the detection spectrum interval is divided into multiple detection spectrum bands with different bandwidths.

[0011] Optionally, the extension in the shortwave and longwave directions includes: Using the wavelength location of the peak spectral intensity as the center position, the wavelengths are extended by 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, and 0.15 μm in the short-wave and long-wave directions, respectively, forming 11 detection bands.

[0012] Optionally, target-to-background radiation contrast Calculated using the following formula: In the formula, The intensity of the engine exhaust spectrum; Atmospheric transmittance; The atmospheric path radiance along the aircraft's flight path; The projected area of ​​the engine exhaust flame in the line-of-sight direction; Let be the instantaneous field of view projected onto the location of the target on the object side, and its value is . , For the instantaneous field of view of the unit detector; The distance between the target and the infrared early warning satellite; The radiance of the Earth and its atmospheric background.

[0013] Optionally, the step of calculating the contrast of each detection spectral band using the arithmetic mean method to optimize the detection spectral bands includes: For each detection spectral band, a target-background radiation contrast sequence distributed along the flight altitude is formed, and an arithmetic average is performed based on the sequence, with the result used as the contrast of the corresponding detection spectral band. The different detection spectral bands are sorted from highest to lowest contrast, with the detection performance of the detection spectral bands ranked earlier being better than that of the detection spectral bands ranked later.

[0014] This invention has at least the following technical effects: Based on the principle of spectral radiation generation of aircraft engine exhaust, the detection spectral range is determined according to the distribution of spectral radiation intensity of engine exhaust at different aircraft flight altitudes, and the selected detection spectral range has better coverage.

[0015] By dividing the detection spectrum into segments and calculating the contrast of each segment at different flight altitudes, and using the arithmetic mean method to obtain the corresponding contrast of each segment, this method can be used as an evaluation index for selecting the best detection spectrum, which helps to improve detection performance during aircraft launch monitoring. Attached Figure Description

[0016] Figure 1 A flowchart of a physical mechanism-based method for selecting the optimal detection spectrum of an aircraft, as provided in an embodiment of the present invention; Figure 2 The flow field distribution diagram of the engine exhaust flame when the aircraft is flying at an altitude of 10km is provided in an embodiment of the present invention; Figure 3 This is a spectral radiation intensity distribution diagram of an engine exhaust flame provided in an embodiment of the present invention. Detailed Implementation

[0017] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a more detailed explanation of the physical mechanism-based method for optimizing the detection spectrum of an aircraft proposed in this invention. 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 for illustrative purposes to aid those skilled in the art 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 proportions, 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.

[0018] like Figure 1 As shown, this embodiment provides a method for optimizing the detection spectrum of an aircraft based on physical mechanisms, including the following steps: Step S1: Based on the radiation generation principle of the aircraft engine exhaust flame, calculate the spectral radiation intensity of the aircraft engine exhaust flame at different flight altitudes.

[0019] Step S2: Based on the distribution of the spectral radiation intensity of the engine exhaust flame at different flight altitudes, determine the detection spectral range and divide the detection spectral range into multiple detection spectral bands.

[0020] Step S3: Combine the detector parameters to calculate the target and background radiation contrast at different flight altitudes in each detection spectrum band.

[0021] Step S4: Based on the contrast between target and background radiation at different flight altitudes under each detection spectrum, the contrast of each detection spectrum is calculated by the arithmetic mean method to optimize the detection spectrum.

[0022] Specifically, in step S1, based on the radiation generation principle of the aircraft engine exhaust flame, the spectral radiation distribution of the engine exhaust flame exhibits significant differences with changes in flight altitude. To calculate the spectral radiation intensity of the aircraft's engine exhaust flame at different flight altitudes, it is necessary to first determine the aircraft's technical parameters and flight environment parameters through data research. Technical parameters include, for example, engine model, engine nozzle size, fuel type, fuel ratio, and nozzle expansion ratio. Flight environment parameters include, for example, the aircraft's flight altitude, flight speed, and the corresponding atmospheric pressure and temperature.

[0023] Furthermore, based on technical and flight environment parameters, hydrodynamic calculations can be performed to obtain the flow field distribution of the aircraft engine exhaust. The flow field distribution mainly includes the flow field temperature distribution, flow field pressure distribution, and flow field composition distribution. For example, when the aircraft's flight altitude is 10 km, the flow field distribution of the engine exhaust is as follows: Figure 2 As shown.

[0024] Finally, based on the calculated flow field distribution and combined with the narrowband K-distribution database, the spectral radiation intensity of the engine exhaust plume at different flight altitudes can be calculated. The distribution of the engine exhaust plume spectral radiation intensity is shown below. Figure 3 As shown.

[0025] Furthermore, in step S2, it can be based on Figure 3 The distribution of the spectral radiation intensity of the engine exhaust plume, as shown, is used to determine the detection spectral range. Specifically, in the shortwave band, the wavelength position where the spectral radiation intensity peak is located can be used as the center position, and the range can be extended in both the shortwave and longwave directions to form a detection spectral range, which can then be divided into multiple detection spectral bands with different bandwidths. Specifically, the range can be extended in both the shortwave and longwave directions to form detection spectral bands of different lengths.

[0026] For example, in the 2–3 μm shortwave band, the wavelength position of the peak spectral radiation intensity at 2.6 μm can be selected as the reference, and then extended towards the shortwave and longwave directions by 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, and 0.15 μm, respectively, forming 11 detection bands. Furthermore, each detection band does not overlap.

[0027] Furthermore, after completing the division of the detection spectrum, in step S3, the target-background radiation contrast corresponding to different flight altitudes and different detection spectrums can be calculated based on the principle of target-background radiation contrast, in combination with the detector parameters.

[0028] Specifically, the target-to-background radiation contrast It can then be calculated using the following formula: In the formula, The intensity of the engine exhaust spectrum; Atmospheric transmittance; The atmospheric path radiance along the aircraft's flight path; The projected area of ​​the engine exhaust flame in the line-of-sight direction; Let be the instantaneous field of view projected onto the location of the target on the object side, and its value is . , The instantaneous field of view of the unit detector (detector parameters); The distance between the target and the infrared early warning satellite; The radiance of the Earth and its atmospheric background.

[0029] By using the above formula, a set of target and background radiation contrasts covering different flight altitudes and different detection spectrum bands can be finally formed.

[0030] Finally, in step S4, the contrast ratio of each detection spectral band can be calculated using the arithmetic mean method to optimize the detection spectral bands. Specifically, based on the set of target and background radiation contrast ratios covering different flight altitudes and different detection spectral bands obtained in step S3, a target and background radiation contrast ratio sequence distributed along the flight altitude can be formed for each detection spectral band. An arithmetic mean is then performed on the sequence, and the calculated result is used as the contrast ratio of the corresponding detection spectral band. Furthermore, different detection spectral bands can be sorted from largest to smallest according to their corresponding contrast ratios, with the detection performance of the detection spectral bands ranked higher being better than those ranked lower, thus completing the optimization of the detection spectral bands.

[0031] This invention is based on the principle of spectral radiation generation from aircraft engine exhaust plumes. It determines the detection spectral band intervals according to the distribution of spectral radiation intensity of engine exhaust plumes at different aircraft flight altitudes, resulting in better coverage of the selected intervals. By dividing the detection spectral bands and calculating the contrast of each band at different flight altitudes, and using the arithmetic mean method to obtain the corresponding contrast of each band, this invention serves as an evaluation index for optimizing the detection spectral bands. This helps improve detection performance during aircraft launch monitoring and represents a significant advancement compared to existing technologies.

[0032] It should be noted that, in this document, 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 limitation, 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.

[0033] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0034] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0035] 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 method for optimizing the detection spectrum of a spacecraft based on physical mechanisms, characterized in that, include: Based on the radiation generation principle of aircraft engine exhaust, the spectral radiation intensity of the aircraft engine exhaust at different flight altitudes is calculated. Based on the distribution of the spectral radiation intensity of the engine exhaust at different flight altitudes, the detection spectral range is determined, and the detection spectral range is divided into multiple detection spectral bands. Based on the detector parameters, the target-background radiation contrast at different flight altitudes under each detection spectrum band is calculated; Based on the contrast between target and background radiation at different flight altitudes in each detection spectral band, the contrast of each detection spectral band is calculated using the arithmetic mean method to optimize the detection spectral band.

2. The method for optimizing the detection spectrum of an aircraft according to claim 1, characterized in that, The calculation of the spectral radiation intensity of the engine exhaust at different flight altitudes, based on the radiation generation principle of the aircraft engine exhaust, includes: Determine the aircraft's technical parameters and flight environment parameters; Based on the technical parameters and flight environment parameters, hydrodynamic calculations are performed to obtain the flow field distribution of the aircraft engine exhaust flame; Based on the aforementioned flow field distribution and combined with the narrowband K-distribution technology database, the spectral radiation intensity of the engine exhaust plume of the aircraft at different flight altitudes is calculated.

3. The method for optimizing the detection spectrum of a spacecraft according to claim 2, characterized in that, The technical parameters include at least: engine model, engine nozzle size, fuel type, fuel ratio, and nozzle expansion ratio; The flight environment parameters include at least: flight altitude, flight speed, and atmospheric environmental pressure and temperature corresponding to the flight altitude.

4. The method for optimizing the detection spectrum of a spacecraft according to claim 2, characterized in that, The flow field distribution includes: flow field temperature distribution, flow field pressure distribution, and flow field component distribution.

5. The method for optimizing the detection spectrum of an aircraft according to claim 1, characterized in that, The method of determining the detection spectral range based on the distribution of engine exhaust spectral radiation intensity at different flight altitudes, and dividing the detection spectral range into multiple detection spectral bands, includes: Based on the distribution of the spectral radiation intensity of the engine exhaust at different flight altitudes, in the shortwave band, the wavelength position where the peak of the spectral radiation intensity is located is taken as the center position, and the spectrum is extended to the shortwave and longwave directions respectively to form the detection spectrum interval, and the detection spectrum interval is divided into multiple detection spectrum bands with different bandwidths.

6. The method for optimizing the detection spectrum of an aircraft according to claim 5, characterized in that, The extension in the shortwave and longwave directions respectively includes: Using the wavelength position where the spectral radiation intensity peak is located as the center position, the wavelengths are extended to the short-wave and long-wave directions by 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, and 0.15 μm, respectively, forming 11 detection bands.

7. The method for optimizing the detection spectrum of a spacecraft according to claim 6, characterized in that, Target vs. background radiation contrast Calculated using the following formula: In the formula, The intensity of the engine exhaust spectrum; Atmospheric transmittance; The atmospheric path radiance along the aircraft's flight path; The projected area of ​​the engine exhaust flame in the line-of-sight direction; Let be the instantaneous field of view projected onto the location of the target on the object side, and its value is . , The instantaneous field of view of the unit detector (detector parameters); The distance between the target and the infrared early warning satellite; The radiance of the Earth and its atmospheric background.

8. The method for optimizing the detection spectrum of an aircraft according to claim 1, characterized in that, The step of calculating the contrast of each detection spectral band using the arithmetic mean method to optimize the detection spectral bands includes: For each detection spectral band, a target-background radiation contrast sequence distributed along the flight altitude is formed, and an arithmetic average is performed based on the sequence, with the result used as the contrast of the corresponding detection spectral band. The different detection spectral bands are sorted from highest to lowest contrast, with the detection performance of the detection spectral bands ranked earlier being better than that of the detection spectral bands ranked later.

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