Method and apparatus for communicating for an aircraft traversing a blackout region

Abstract

The application relates to a communication method and device for an aircraft crossing a black barrier area, belonging to the technical field of aerospace, and aims to solve the problems of the existing communication black barrier problem relieving method. The method comprises the following steps: obtaining the plasma parameters of the plasma sheath under different flight states by simulating the generation process of the black barrier through ground experiment or computer simulation; selecting N typical flight states to obtain the preset communication window positions corresponding to each flight state; arranging an adjustable gain metamaterial module at each of the N preset communication window positions on the inner surface of the aircraft; when the aircraft crosses the black barrier area, obtaining the actual communication window positions according to the plasma parameters of the plasma sheath at different positions in the actual flight, moving the metamaterials at the adjacent preset communication window positions to the actual communication window positions, adjusting the parameters of the metamaterials, matching the metamaterials with the plasma sheath impedance, and then realizing the communication between the aircraft interior and the outside world.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for breaking through the communication black barrier, belonging to the field of aerospace technology. BACKGROUND

[0002] With the world aerospace entering a new stage represented by large-scale space infrastructure construction, space resource development, manned lunar and Mars exploration, the demand for space entry is growing rapidly, and accordingly higher requirements are put forward for the space transportation system. However, when the flight vehicle flies at a speed of 10Ma or more in the near space segment (20-90km), the high-density, strong-collision, non-uniform, high-dynamic plasma sheath formed on its surface due to thermal ionization will absorb, reflect, refract and scatter electromagnetic waves, causing communication signals to be attenuated or even completely shielded, resulting in communication interruption of the flight vehicle. In addition, the plasma sheath will change the antenna matching characteristics of the flight vehicle, causing impedance mismatch and resonance point shift. At the same time, the plasma sheath is affected by turbulence, and the sheath parameters change dramatically with high dynamic characteristics (~100kHz order), so that the communication signal amplitude and phase change makes it difficult to be captured, tracked and received and demodulated, further deteriorating the communication environment. The communication quality decline or even interruption caused by the plasma sheath will cause the flight vehicle to become an "information island", leading to a series of serious consequences such as parameter unknown, target invisible and state uncontrollable, and further seriously threatening the safety of the flight vehicle and the crew inside, which is one of the main factors restricting the establishment of space transportation product system.

[0003] To solve this problem, according to the existing literature, the methods to alleviate the communication interruption of high-speed flight vehicles can be divided into two categories. One is to change the plasma flow field characteristics to reduce the attenuation of communication signals by the plasma sheath, such as electron injection, changing the attack angle, magnetic window method, orthogonal electric / magnetic field method, etc. The other is to seek new communication means from the perspective of electromagnetic wave and plasma interaction without changing the plasma sheath, such as low frequency method, high frequency method, relay method, super material matching method, etc.

[0004] In the field of patents, around the active change of flow field characteristics, application number CN202211504205.4 discloses a catalytic coating for mitigating communication blackout of reentry vehicles and its preparation method, based on the surface catalytic effect of copper coating, the electron number density of reentry vehicle surface and wake region is reduced, but the coating method has the disadvantages of limited use time and may affect its own normal communication in non-blackout area. Application number CN202111355853.3 discloses a method for breaking through the communication blackout of plasma sheath by actively weakening the shock wave, which uses the shock wave generated by active discharge to modulate the electron density distribution and shape of plasma, thereby alleviating the blackout problem. Application number CN202110716664.8 discloses a method for mitigating communication blackout of high-speed vehicles, which reduces the electron density of plasma sheath by releasing carbon dioxide, which can effectively reduce the plasma cutoff frequency of the communication target area. However, the problems of shock wave method and electron-injection method are that the load is large, which is not suitable for long-distance flight. Around the interaction of electromagnetic wave and plasma, application number CN201810461835.5 discloses an experimental device for controlling the strong dissipation plasma in the blackout area of spacecraft by pulse magnetic field, which adjusts the electron distribution and characteristics of plasma by pulse magnetic field, and effectively improves the utilization rate of electric energy. Application number CN202211602396.8 discloses a structure and method for breaking through the plasma communication blackout and a spacecraft, which places a lattice structure composed of multiple high dielectric constant materials in the plasma, so that electromagnetic waves can propagate forward in the form of evanescent waves. However, this method needs to change the shape of the spacecraft, and cannot solve the signal attenuation caused by strong collision. Application number CN201310476799.7 discloses a magnetic window antenna for overcoming the communication blackout of near space plasma sheath, which magnetizes the plasma in the communication target area to reduce the attenuation of electromagnetic wave transmission in the plasma. Application numbers CN201911301601.5 and CN201710049140.1 disclose a X-ray communication system and method in the blackout area, which can realize X-ray communication in the blackout area by increasing the frequency of electromagnetic signals. Application number CN201910893562.6 discloses a system for realizing terahertz tracking and data relay communication integration, which uses the high frequency and high bandwidth characteristics of terahertz signals to meet the communication demand in the blackout condition. Application number CN201610056782.X discloses a reentry vehicle communication system for breaking through the blackout, which uses the high frequency characteristics of laser to realize reliable communication in the blackout area. However, the high frequency method of X-ray, terahertz and laser is easily affected by weather environment and ablation particles in the plasma sheath, and the reliability in practical application is difficult to guarantee.

[0005] In summary, the current research on the communication blackout problem mitigation method still has the following problems:

[0006] (1) System load is relatively large, system flexibility, reliability is insufficient, use scene is limited;

[0007] (2) Lack of comprehensive consideration of high density, strong collision, non-uniform and high dynamic characteristics of the plasma sheath.

[0008] It is urgent to develop a new type of communication black barrier mitigation method with higher reliability and better applicability. SUMMARY

[0009] In view of the problems existing in the existing communication black barrier problem mitigation method, the application provides a communication method and device for an aircraft passing through a black barrier area.

[0010] In one aspect of the application, the communication method for the aircraft passing through the black barrier area comprises the following steps:

[0011] Step 1: simulate the generation process of the black barrier through ground experiment or computer simulation to obtain the plasma parameters of the plasma sheath under different flight states;

[0012] Step 2: select N typical flight states to obtain the preset communication window position corresponding to each flight state;

[0013] In each flight state, the plasma parameters of the plasma sheath at different positions are compared and selected to determine the angular frequency ω of the electromagnetic wave and the preset communication window position;

[0014] Step 3: an adjustable gain metamaterial module is arranged at each of the N preset communication window positions on the inner surface of the aircraft, and the adjustable gain metamaterial module comprises a metamaterial, a tuning unit and a position layer fine adjustment unit;

[0015] Step 4: when the aircraft passes through the black barrier area, the plasma parameters of the plasma sheath at different positions in actual flight are obtained;

[0016] Step 5: the actual communication window position is obtained according to the plasma parameters of the plasma sheath at different positions in the actual flight, the preset communication window position adjacent to the actual communication window position is found, the metamaterial at the preset communication window position is moved to the actual communication window position, and the parameters of the metamaterial are adjusted, so that the metamaterial moved to the actual communication window position is matched with the plasma sheath impedance, and then the communication between the inside of the aircraft and the outside is maintained.

[0017] Preferably, the plasma parameters of the plasma sheath include electron density n e Normal distribution, collision frequency v and thickness d p .

[0018] Preferably, the preset communication window position and the actual communication window position are determined in the same way, and the determination process of the actual communication window position is as follows:

[0019] First, the plasma parameters at different positions of the plasma sheath are obtained;

[0020] Second, the electron density n e is obtained according to the electron density n p :

[0021]

[0022] In the formula, ε0 represents the dielectric constant in vacuum; m e is the electron mass; and e represents the elementary charge amount.

[0023] Finally, the position satisfying the following three constraint conditions is found as the actual communication window position, and the angular frequency ω of the electromagnetic wave achieving impedance matching is obtained:

[0024] Constraint condition 1: the maximum value of the normalized normal plasma frequency is less than or equal to 5:

[0025] ω pmax / ω≤5, ω pmax is the maximum value of the normal distribution of the plasma frequency ω p at any position;

[0026] Constraint condition 2: the normalized plasma collision frequency is less than or equal to 2:

[0027] v / ω≤2

[0028] Constraint condition 3: the normalized plasma thickness is less than or equal to 0.1:

[0029] d p / λ≤0.1, λ is the wavelength of the electromagnetic wave;

[0030] The parameters of the plasma sheath at the actual communication window position are as follows: the plasma thickness the normal distribution of the relative dielectric constant of the plasma and is the normal distribution of the plasma frequency at the actual communication window position, ω * is the frequency of the electromagnetic wave satisfying the constraint condition, and v * is the plasma collision frequency at the actual communication window position.

[0031] Preferably, the super material parameters in step five include the relative dielectric constant ε m , the relative magnetic permeability μ m , and the thickness d m .

[0032] Preferably, the adjustment of metamaterial parameters includes:

[0033] The position of the metamaterial is adjusted to the actual communication window position using a position layer fine-tuning unit, and the thickness of the metamaterial is adjusted by changing the number of metamaterial layers; the thickness of the metamaterial...

[0034] The relative permittivity ε of the metamaterial is adjusted using a tuning unit. m and relative permeability μ m Specifically:

[0035] The relative permittivity ε of metamaterials m Adjusted to: Where mean represents the arithmetic mean of the distribution along the normal direction;

[0036] The relative permeability μ of metamaterials m Adjustment method: Change the relative permeability μ of the metamaterial m To adjust the equivalent wave impedance of the plasma and the tunable gain metamaterial module, when the matched transmission rate T m Greater than 0.9 or transmission gain T gain Stop adjusting when the value exceeds 10 dB; at this point, the relative permeability μ... m This is the target value.

[0037] Preferably, the transmission rate T m Transmission gain T gain Satisfying the relation:

[0038]

[0039] In the formula, T p This indicates the transmission rate of electromagnetic waves in the plasma when no tunable gain metamaterial module is installed for matching.

[0040] In another aspect of the present invention, a communication device is provided for the aircraft to traverse a blackout region, the communication device comprising a plasma parameter diagnostic module 1, a calculation and decision module 2, a tunable gain metamaterial module 3, and a communication module 4;

[0041] When passing through the blackout area, a plasma sheath 5 is formed on the outside of the aircraft;

[0042] The tunable gain metamaterial module 3 includes a metamaterial, a tuning unit, and a position layer fine-tuning unit; the metamaterial is set at N preset communication window positions on the inner surface of the spacecraft;

[0043] The plasma parameter diagnosis module 1 is used to acquire plasma parameters at different locations of the plasma sheath and send them to the calculation and decision module 2.

[0044] The computing decision module 2 is used for traversing the plasma parameters of the plasma sheath at different positions, and finding a position satisfying the following three constraint conditions as the actual communication window position:

[0045] Constraint condition 1: the maximum value of the normalized normal plasma frequency is less than or equal to 5:

[0046] ω pmax / ω≤5, ω pmax is the maximum value of the normal distribution ω p of the plasma frequency at any position;

[0047] Constraint condition 2: the normalized plasma collision frequency is less than or equal to 2:

[0048] v / ω≤2

[0049] Constraint condition 3: the normalized plasma thickness is less than or equal to 0.1:

[0050] d p / λ≤0.1, λ is the wavelength of the electromagnetic wave;

[0051] After the actual communication window position is determined, the target values of the thickness, the relative permittivity and the relative permeability of the impedance matching metamaterial are obtained;

[0052] The computing decision module 2 is also used for issuing instructions to the tunable gain metamaterial module according to the target values, adjusting the position of the metamaterial to the actual communication window position by using the position layer fine adjustment unit, and adjusting the thickness of the metamaterial by adjusting the number of layers of the metamaterial, and adjusting the relative permittivity and the relative permeability of the metamaterial by using the tuning unit;

[0053] The communication module 4 is used for communicating with the outside through the metamaterial at the actual communication window position.

[0054] The beneficial effects of the present application are:

[0055] The present application uses the lightweight metamaterial to be laid on the inner surface of the aircraft, which has little influence on the weight of the aircraft system, and realizes small load loading; the system integrates parameter diagnosis and electromagnetic regulation, and uses the gain and tunable characteristics of the metamaterial to overcome the loss caused by high density and strong collision of the plasma sheath in multiple flight states at the same time, find the communication window, and adjust the parameters of the metamaterial to the optimum, so as to reach the impedance matching state, and effectively guarantee the communication between the aircraft interior and the outside. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is the system principle block diagram of the communication method of the aircraft passing through the black barrier region of the present application.

[0057] Figure 2is a schematic diagram of matching of metamaterial and plasma sheath;

[0058] Figure 3 is a correlation curve of example 1, wherein Figure 3 (a) is a normalized plasma frequency ω p / ω linearly increasing distribution along the normal direction, Figure 3 (b) is a transmission gain curve after matching.

[0059] Figure 4 is a correlation curve of example 2, wherein Figure 4 (a) is a normalized plasma frequency ω p / ω linearly decreasing distribution along the normal direction, Figure 4 (b) is a transmission gain curve after matching.

[0060] Figure 5 is a correlation curve of example 3, wherein Figure 5 (a) is a normalized plasma frequency ω p / ω parabolic distribution along the normal direction, Figure 5 (b) is a transmission gain curve after matching. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0062] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0063] The present application will be further described below with reference to the drawings and specific embodiments, but is not limited to the present application.

[0064] Specific embodiment one: the present embodiment will be described below with reference to Figure 1 and Figure 2 The communication method of the aircraft passing through the black barrier region, which comprises the following steps:

[0065] Step one, simulate the generation process of the black barrier through ground experiments or computer simulation to obtain the plasma parameters of the plasma sheath under different flight states.

[0066] The plasma parameters of the plasma sheath include the electron density n e normal distribution, collision frequency v and thickness d p .

[0067] Step two, select N typical flight states, and obtain the preset communication window position corresponding to each flight state;

[0068] In each flight state, the plasma parameters of different positions of the plasma sheath are compared and selected, and then the angular frequency ω of the electromagnetic wave and the preset communication window position are determined;

[0069] This step selects typical flight states, and calculates the preferred position for maintaining communication between the inside and outside of the spacecraft in each typical flight state as the preset communication window position. N preset communication window positions can be obtained corresponding to N typical flight states.

[0070] Step three, set a tunable gain metamaterial module at each of the N preset communication window positions on the surface of the spacecraft, which includes metamaterial, tuning unit and position layer fine adjustment unit;

[0071] Steps one to three are pre-treatment before the actual flight of the spacecraft, the purpose of which is to find N preset communication windows, and to apply metamaterials in each preset communication window in advance, so as to facilitate subsequent position micro-shift and parameter adjustment of the metamaterials.

[0072] Step four, when the spacecraft passes through the black barrier area, obtain the plasma parameters of different positions of the plasma sheath in the actual flight;

[0073] Step five, obtain the actual communication window position according to the plasma parameters of different positions of the plasma sheath in the actual flight, find the preset communication window position adjacent to the actual communication window position, micro-shift the metamaterial of the preset communication window position to the actual communication window position, and adjust the parameters of the metamaterial, so that the metamaterial shifted to the actual communication window position is matched with the plasma sheath impedance, and then the communication between the inside and outside of the spacecraft is maintained.

[0074] In the actual flight, for a certain typical flight state, the plasma parameters of the plasma sheath will be different from those in step one, so this step will recalculate the communication window position (actual communication window position) according to the actually obtained plasma parameters. There must be a preset communication window adjacent to the actual communication window position near the actual communication window position. In this step, the metamaterial of the preset communication window is moved over, and its parameters are adjusted to meet the requirement that the transmission rate T m is greater than 0.9 or the transmission gain T gain is greater than 10 dB, to ensure normal communication between the spacecraft and the outside world.

[0075] The determination method of the preset communication window position and the actual communication window position is the same, and the determination process of the actual communication window position is as follows:

[0076] Firstly, the plasma parameters at different positions of the plasma sheath are obtained; for the preset communication window position, the plasma parameters are obtained by step one, and for the actual communication window position, the plasma parameters are the data collected in the actual flight process; secondly, the normal distribution of the plasma frequency at any position is obtained according to the electron density n e The normal distribution of the plasma frequency at any position is obtained according to the electron density n p :

[0077]

[0078] In the formula, ε0 represents the dielectric constant in vacuum; m e is the electron mass; e represents the elementary charge amount;

[0079] For the plasma sheath, the electron density at different positions is non-uniformly distributed along the normal direction, which is characterized by n e .

[0080] Finally, the position satisfying the following three constraint conditions is found as the actual communication window position, and the angular frequency ω of the impedance matching electromagnetic wave is obtained:

[0081] Constraint condition 1: the maximum value of the normalized normal plasma frequency is less than or equal to 5:

[0082] ω pmax / ω≤5, ω pmax is the maximum value of the normal distribution of the plasma frequency ω p at any position; the non-uniform distribution of the plasma frequency of the normal distribution at any position of the plasma sheath, wherein the maximum value is ω pmax :

[0083] Constraint condition 2: the normalized plasma collision frequency is less than or equal to 2:

[0084] v / ω≤2

[0085] Constraint condition 3: the normalized plasma thickness is less than or equal to 0.1:

[0086] d p / λ≤0.1, λ is the wavelength of the electromagnetic wave;

[0087] The above three constraint conditions are to normalize the non-uniformity of the plasma frequency, the collision frequency and the thickness in a suitable range, so as to ensure that the metamaterial can be used for impedance matching, and the overall transmission efficiency is improved.

[0088] The parameters of the plasma sheath at the actual communication window position are: the plasma thickness The normal distribution of the relative dielectric constant of the plasma and For the normal distribution of plasma frequency at the actual communication window location, ω * To satisfy the constraints, the electromagnetic wave frequency, v * This represents the plasma collision frequency at the actual communication window location.

[0089] In step five, the metamaterial parameters include the relative permittivity ε. m Relative permeability μ m and thickness d m .

[0090] Adjusting metamaterial parameters includes:

[0091] The position of the metamaterial is adjusted to the actual communication window position using a position layer fine-tuning unit, and the thickness of the metamaterial is adjusted by changing the number of metamaterial layers; the thickness of the metamaterial...

[0092] The relative permittivity ε of the metamaterial is adjusted using a tuning unit. m and relative permeability μ m Specifically:

[0093] The relative permittivity ε of metamaterials m Adjusted to: Where mean represents the arithmetic mean of the distribution along the normal direction;

[0094] The relative permeability μ of metamaterials m Adjustment method: Change the relative permeability μ of the metamaterial m To adjust the equivalent wave impedance of the plasma and the tunable gain metamaterial module, when the matched transmission rate T m Greater than 0.9 or transmission gain T gain Stop adjusting when the value exceeds 10 dB; at this point, the relative permeability μ... m This is the target value.

[0095] Transmission rate T m Transmission gain T gain Satisfying the relation:

[0096]

[0097] In the formula, T p This indicates the transmission rate of electromagnetic waves in the plasma when no tunable gain metamaterial module is installed for matching.

[0098] Specific Implementation Method Two: The following is combined with... Figures 1 to 5The communication device for the aircraft to pass through the black obstacle area in the embodiment is based on the communication method for the aircraft to pass through the black obstacle area in the first embodiment, and the communication device comprises a plasma parameter diagnosis module 1, a calculation decision module 2, a tunable gain metamaterial module 3 and a communication module 4.

[0099] When passing through the black obstacle area, a plasma sheath 5 is formed outside the aircraft.

[0100] The tunable gain metamaterial module 3 comprises a metamaterial, a tuning unit and a position layer number fine adjustment unit; the metamaterial is arranged at N preset communication window positions on the inner surface of the aircraft.

[0101] The plasma parameter diagnosis module 1 is used to obtain the plasma parameters of the plasma sheath at different positions and send them to the calculation decision module 2.

[0102] The calculation decision module 2 is used to traverse the plasma parameters of the plasma sheath at different positions and find a position that satisfies the following three constraint conditions as the actual communication window position.

[0103] Constraint condition 1: the maximum value of the normalized normal plasma frequency is less than or equal to 5:

[0104] ω pmax / ω≤5, ω pmax is the maximum value of the normal distribution ω p of the plasma frequency at any position;

[0105] Constraint condition 2: the normalized plasma collision frequency is less than or equal to 2:

[0106] v / ω≤2

[0107] Constraint condition 3: the normalized plasma thickness is less than or equal to 0.1:

[0108] d p / λ≤0.1, λ is the wavelength of the electromagnetic wave;

[0109] After the actual communication window position is determined, the target values of the thickness, the relative permittivity and the relative permeability of the impedance matching metamaterial are obtained;

[0110] The calculation decision module 2 is also used to issue an instruction to the tunable gain metamaterial module according to the target values, adjust the position of the metamaterial to the actual communication window position by using the position layer number fine adjustment unit, adjust the thickness of the metamaterial by adjusting the number of layers of the metamaterial, and adjust the relative permittivity and the relative permeability of the metamaterial by using the tuning unit.

[0111] The communication module 4 is used to communicate with the outside through the metamaterial at the actual communication window position.

[0112] Several examples are given below: Specific Implementation Example 1

[0114] At the preset communication window location, metamaterials are laid inside the spacecraft. A double-layer matching structure consisting of the tunable gain metamaterial module 3 and the plasma sheath 5 is shown below. Figure 2 As shown, the two are tightly connected, with vacuum on both sides. A transversely magnetically polarized electromagnetic wave (angular frequency ω = 1 GHz, wavelength λ = 30 cm) is incident perpendicularly from one side of the metamaterial. During actual flight, the actual communication window position is obtained, and the metamaterial is moved to that position. Then, the plasma normal frequency distribution of the plasma sheath of that actual communication window is obtained. In this example, the normalized plasma frequency along the normal direction of the plasma sheath is linearly increasing (e.g., ...). Figure 3 (a) shows that the thickness of the plasma sheath is equal when the positions of the metamaterial and the actual communication window are adjusted. The collision frequency v of the plasma sheath * =2ω * Furthermore, the relative transport rate T after matching with a tunable gain metamaterial varies with the relative permeability μ of the metamaterial. m The relationship of change is as follows Figure 3 As shown in (b), it can be seen that when μ m At -0.71, the maximum relative transfer rate is 1.658. Additionally, the relative permittivity ε of the metamaterial... m Adjusted to:

[0115] The results show that the aircraft can communicate normally when passing through the blackout. Specific Implementation Example 2

[0117] At the preset communication window location, metamaterials are laid inside the spacecraft, and a double-layer matching structure consisting of the tunable gain metamaterial module 3 and the plasma sheath 5 is as follows: Figure 2 As shown, the two are tightly connected, with vacuum on both sides. A transversely magnetically polarized electromagnetic wave (angular frequency ω = 1 GHz, wavelength λ = 30 cm) is incident perpendicularly from one side of the metamaterial. During actual flight, the actual communication window position is obtained, and the metamaterial is moved to that position. Then, the plasma normal frequency distribution of the plasma sheath of that actual communication window is obtained. In this example, the normalized plasma frequency along the normal direction of the plasma sheath is linearly decreasing (e.g., ...). Figure 4 (a) shows that the thickness of the plasma sheath is equal when the positions of the metamaterial and the actual communication window are adjusted. The collision frequency v of the plasma sheath * =0.5ω * Furthermore, the relative transmission gain T after matching with a tunable gain metamaterial gain With the relative magnetic permeability μ of the metamaterialm The relationship between the relative permeability μ Figure 4 (b) can be seen that when μ m = 1.29, the maximum transmission rate is 2.198. In addition, the relative permittivity ε m is adjusted as follows: The results show that the aircraft can communicate normally when crossing the black barrier. Specific embodiment 3

[0119] In the preset communication window position, the aircraft is internally coated with metamaterials, and the double-layer matching structure composed of the tunable gain metamaterial module 3 and the plasma sheath 5 is as shown in Figure 2 (b). The two are closely connected, and the two sides are vacuum. The transverse magnetic polarized electromagnetic wave (the electromagnetic wave angular frequency is ω = 1 GHz, and the wavelength is λ = 30 cm) is vertically incident from the metamaterial side. In actual flight, the actual communication window position is obtained, and the metamaterial is moved to the position, and then the plasma frequency distribution of the actual communication window plasma sheath is obtained. In this example, the normalized plasma frequency of the plasma sheath along the normal direction is a parabolic distribution (as shown in Figure 5 (a)), and the thickness of the metamaterial and the plasma sheath of the actual communication window position is adjusted to be equal The collision frequency v * = 5ω * of the plasma sheath. Further, the relative transmission gain T gain of the metamaterial after the tunable gain metamaterial matching changes with the relative permeability μ m of the metamaterial as shown in Figure 5 (b). It can be seen that when μ m = -0.91, the maximum relative transmission gain T gain is 10.13 dB. In addition, the relative permittivity ε m of the metamaterial is adjusted as follows: The results show that the aircraft can communicate normally when crossing the black barrier.

[0120] Although the present application is described herein with reference to particular embodiments, it is to be understood that these examples are merely illustrative of principles and applications of the present application. It should therefore be understood that numerous modifications can be made to the illustrative embodiments and that other arrangements can be devised without departing from the spirit and scope of the present application as defined by the appended claims. It should be understood that the features described in connection with one embodiment can be used in conjunction with other embodiments described herein. It should also be understood that features described in connection with separate embodiments can be used in other described embodiments.

Claims

1. A communication method for an aircraft traversing a blackout region, characterized in that, The method includes the following steps: Step 1: Simulate the blackout process through ground-based experiments or computer simulations to obtain plasma parameters of the plasma sheath under different flight conditions; the plasma parameters of the plasma sheath include electron density n. e Normal distribution, collision frequency v, and thickness d p ; Step 2: Select N typical flight states and obtain the preset communication window position corresponding to each flight state; By comparing plasma parameters at different positions of the plasma sheath under each flight condition, the angular frequency ω of the electromagnetic wave and the preset communication window position are determined. Step 3: Set up a tunable gain metamaterial module at each of the N preset communication window positions on the inner surface of the aircraft. The tunable gain metamaterial module includes a metamaterial, a tuning unit, and a position layer fine-tuning unit. Step 4: When the aircraft passes through the blackout area, obtain the plasma parameters at different positions of the plasma sheath during actual flight; Step 5: Obtain the actual communication window position based on the plasma parameters at different positions of the plasma sheath during actual flight, find the preset communication window position adjacent to the actual communication window position, move the metamaterial at the preset communication window position to the actual communication window position, and adjust the parameters of the metamaterial so that the metamaterial moved to the actual communication window position is impedance matched with the plasma sheath, thereby enabling the spacecraft to maintain communication with the outside world. The preset communication window position and the actual communication window position are determined in the same way. The process for determining the actual communication window position is as follows: First, plasma parameters at different locations of the plasma sheath were obtained; Secondly, according to the electron density n e Normal distribution obtains the normal distribution ω of plasma frequency at any location. p : In the formula, ε0 represents the dielectric constant in vacuum; m e Here, e represents the electron mass; e represents the elementary charge. Finally, the position that satisfies the following three constraints is selected as the actual communication window position, and the angular frequency ω of the impedance-matched electromagnetic wave is obtained: Constraint 1: The maximum value of the normalized normal plasma frequency is less than or equal to 5. ω pmax / ω≤5,ω pmax The normal distribution ω of plasma frequency at any location p The maximum value; Constraint 2: Normalized plasma collision frequency is less than or equal to 2. v / ω≤2 Constraint 3: Normalized plasma thickness is less than or equal to 0.

1. d p / λ≤0.1, where λ is the wavelength of the electromagnetic wave; The parameters for the plasma sheath at the actual communication window location are: plasma thickness. Normal distribution of the relative permittivity of plasma and For the normal distribution of plasma frequency at the actual communication window location, ω * To satisfy the constraints, the electromagnetic wave frequency, v * The plasma collision frequency at the actual communication window location; The metamaterial parameters in step five include the relative permittivity ε. m Relative permeability μ m and thickness d m ; Adjusting metamaterial parameters includes: The position of the metamaterial is adjusted to the actual communication window position using a position layer fine-tuning unit, and the thickness of the metamaterial is adjusted by changing the number of metamaterial layers; the thickness of the metamaterial... The relative permittivity ε of the metamaterial is adjusted using a tuning unit. m and relative permeability μ m Specifically: The relative permittivity ε of metamaterials m Adjusted to: Where mean represents the arithmetic mean of the distribution along the normal direction; The relative permeability μ of metamaterials m Adjustment method: Change the relative permeability μ of the metamaterial m To adjust the equivalent wave impedance of the plasma and the tunable gain metamaterial module, when the matched transmission rate T m Greater than 0.9 or transmission gain T gain Stop adjusting when the value exceeds 10 dB; at this point, the relative permeability μ... m This is the target value.

2. The communication method for an aircraft traversing a blackout region according to claim 1, characterized in that, Transmission rate T m Transmission gain T gain Satisfying the relation: In the formula, T p This indicates the transmission rate of electromagnetic waves in the plasma when no tunable gain metamaterial module is installed for matching.

3. A communication device for an aircraft traversing a blackout region, implemented based on the communication method for an aircraft traversing a blackout region as described in claim 1 or 2, characterized in that, The communication device includes a plasma parameter diagnosis module (1), a calculation and decision module (2), a tunable gain metamaterial module (3), and a communication module (4); When passing through the blackout area, a plasma sheath is formed on the outside of the aircraft (5); The tunable gain metamaterial module (3) includes a metamaterial, a tuning unit, and a position layer fine-tuning unit; Metamaterials are placed at N pre-defined communication window positions on the inner surface of the aircraft; The plasma parameter diagnosis module (1) is used to obtain the plasma parameters of the plasma sheath at different locations and send them to the calculation and decision module (2); The calculation and decision module (2) is used to traverse the plasma parameters at different positions of the plasma sheath and find the position that simultaneously satisfies the following three constraints as the actual communication window position: Constraint 1: The maximum value of the normalized normal plasma frequency is less than or equal to 5. ω pmax / ω≤5,ω pmax The normal distribution ω of plasma frequency at any location p The maximum value; Constraint 2: Normalized plasma collision frequency is less than or equal to 2. v / ω≤2 Constraint 3: Normalized plasma thickness is less than or equal to 0.

1. d p / λ≤0.1, where λ is the wavelength of the electromagnetic wave; After the actual communication window position is determined, the target values ​​of the metamaterial thickness, relative permittivity, and relative permeability for impedance matching are obtained. The calculation decision module (2) is also used to issue instructions to the tunable gain metamaterial module (3) according to the target value, adjust the position of the metamaterial to the actual communication window position by using the position layer fine-tuning unit, adjust the metamaterial thickness by adjusting the number of metamaterial layers, and adjust the relative permittivity and relative permeability of the metamaterial by using the tuning unit. The communication module (4) is used to communicate with the outside world through the metamaterial at the actual communication window position.

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