Over-the-horizon communication parameter dynamic adjustment method based on evaporation waveguide

Abstract

The invention relates to the field of radio transmission, and discloses an evaporation waveguide-based beyond-visual-range communication parameter dynamic adjustment method, which comprises the following steps of: installing a meteorological sensor and a hydrological sensor at a specified height of an offshore launching platform, and obtaining meteorological and hydrological data at the specified height; calculating to obtain an evaporation waveguide height diagnostic value and an atmospheric correction refractive index profile by using the obtained meteorological and hydrological data; according to the obtained atmosphere correction refractive index profile, the lowest trapping frequency and the critical incident angle in the current environment are obtained through calculation; determining a communication frequency range and antenna parameter ranges of the transmitting end and the receiving end; and searching in a communication frequency range and an antenna parameter range by adopting a particle swarm optimization algorithm to obtain the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration. According to the method disclosed by the invention, the optimal frequency capable of carrying out beyond visual range communication in the evaporation waveguide environment can be output in real time, and the antenna parameters of the system are dynamically adjusted through the antenna servo system according to the meteorological and hydrological environment.

Description

Technical Field

[0001] The present invention relates to the field of radio transmission, and particularly to a method for dynamically adjusting parameters of over-the-horizon communication based on evaporation duct. Background Art

[0002] Currently, in the fields of marine communication, long-distance information transmission, shipborne systems, emergency response, etc., the demand for high-reliability and high-bandwidth wireless communication is increasing day by day.

[0003] Evaporation duct is a common abnormal refraction phenomenon in the near-surface atmosphere, which can form a low-loss propagation channel for electromagnetic waves under specific meteorological conditions, thereby realizing over-the-horizon communication. Over-the-horizon communication based on evaporation duct has the advantages of long propagation distance and high bandwidth utilization rate, and has important application value in the marine environment. However, the existing over-the-horizon communication systems generally have the following problems: they cannot identify and judge the formation and change of evaporation duct according to real-time meteorological conditions; they lack a dynamic adaptive adjustment mechanism for parameters such as communication frequency, antenna height and elevation angle; most are based on fixed parameters measured once, and the performance of the communication system fluctuates greatly when the waveguide environment changes, and the reliability is insufficient.

[0004] Therefore, there is an urgent need for a method that can dynamically sense the evaporation duct structure in the complex marine environment and select the parameters of the over-the-horizon communication system in real time. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for dynamically adjusting parameters of over-the-horizon communication based on evaporation duct, which can output the optimal frequency for over-the-horizon communication in the evaporation duct environment in real time and dynamically adjust the system antenna parameters according to the meteorological and hydrological environment through the antenna servo system.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for dynamically adjusting parameters of over-the-horizon communication based on evaporation duct includes the following steps: Step 1, acquisition of observation data: Install meteorological and hydrological sensors at a specified height on a marine launch platform to obtain meteorological and hydrological data at the specified height; Step 2, acquisition of atmospheric modified refractive index profile: Use the obtained meteorological and hydrological data at the specified height to calculate the diagnostic value of the evaporation duct height through the evaporation duct model; Use the logarithmic linear function of the atmospheric modified refractive index profile with respect to the evaporation duct height to obtain the corresponding atmospheric modified refractive index profile; Step 3, acquisition of the lowest trapped frequency and the critical incident angle: According to the obtained atmospheric modified refractive index profile, calculate its refractive index gradient and evaporation duct height to obtain the lowest trapped frequency in the current environment; At the same time, calculate the waveguide strength according to the modified refractive index profile, and further obtain the critical incident angle; Step 4: Determine the communication frequency range and the antenna parameter ranges at the transmitting and receiving ends based on the lowest trapping frequency, critical incident angle, evaporation duct height, and empirical values. Step 5: Use the particle swarm optimization algorithm to search within the communication frequency range and the antenna parameter ranges to obtain the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration.

[0008] In the above solution, the meteorological and hydrological data in Step 1 include the observed data of air pressure, atmospheric temperature, relative humidity, wind speed, and sea surface temperature.

[0009] In the above solution, the evaporation duct models in Step 2 include the PJ, NPS, BYC, NWA, LKB, or NRL models.

[0010] In the above solution, in Step 2, the atmospheric modified refractive index is calculated as follows: ; In the formula: is the atmospheric modified refractive index at a height of 0 m, is the height, is the atmospheric modified refractive index at a height of z, = 0.00015 m, is the evaporation duct height.

[0011] In the above solution, in Step 3, the lowest trapping frequency is calculated as follows: ; In the formula, is the atmospheric modified refractive index, is the height, is the evaporation duct height.

[0012] In the above solution, in Step 3, the critical incident angle Its expression is as follows: ; In the formula, is the duct strength, , is the atmospheric modified refractive index at a height of 0 m, is the minimum value of the atmospheric modified refractive index.

[0013] In the above solution, in Step 4, the determined communication frequency range is , where is the lowest trapping frequency, is 12.5 GHz.

[0014] In the above solution, in step four, the antenna parameters of the transmitter and the receiver include the height of the transmitting antenna , the height of the receiving antenna , the elevation angle of the transmitting antenna and the elevation angle of the receiving antenna . The determined range of antenna parameters is: the height of the transmitting antenna , the height of the receiving antenna , the elevation angle of the transmitting antenna , the elevation angle of the receiving antenna , is the evaporation duct height, is the critical incident angle

[0015] In the above solution, the specific method of step five is as follows First, calculate the link distance based on the longitude and latitude information of the transmitting platform and the receiving platform : ; wherein, is the radius of the earth, are the latitudes of the transmitter and the receiver respectively, expressed in radians; are the longitudes of the transmitter and the receiver respectively, expressed in radians; is the longitude difference between the transmitter and the receiver; Secondly, construct the propagation loss function : ; In the formula: is the antenna height; is the electromagnetic wave frequency; is the distance in the horizontal direction; M is the atmospheric correction refractive index profile; is the propagation factor, which is a function of the transmitting antenna frequency, antenna height, antenna elevation angle, link distance and atmospheric correction refractive index profile, and can be calculated by the parabolic equation method, with the unit of V / m; Then, according to the determined link distance and the loss function use the particle swarm optimization algorithm for optimization, and output the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration

[0016] In a further technical solution, the specific method of using the particle swarm optimization algorithm for optimization is as follows (1) Parameter initialization, set the particle swarm size and the maximum number of iterations , define the multi-dimensional search parameter space, including the following variables: communication frequency , the height of the transmitting antenna , the height of the receiving antenna 、 Elevation angle of transmitting antenna 、 Elevation angle of receiving antenna ; For each particle Randomly initialize its position vector in the above five-dimensional search space and velocity vector ; (2) Calculate the fitness, with the minimum propagation loss and the distance in the horizontal direction being the link distance between the transmitting platform and the receiving platform Under the condition, design the fitness function as: ; (3) Update the particle velocity and position, and perform individual optimal and global optimal guidance; ; Among them, is the inertia weight, represents the velocity vector of the rd particle at the th iteration, represents the position vector of the rd particle at the th iteration, represents the velocity of the th particle at the th iteration, represents the updated position of the th particle after the th iteration, are the individual and group learning factors, and the value range is is a uniformly random number between, is the historical optimal position of particle at the th iteration, is the global optimal position of the current group at the th iteration; (4) Repeat steps (2) and (3) until the termination condition is reached, and output the optimal parameter combination of the final particle swarm: ; That is, find the frequency point with the minimum propagation loss in the search space, and output the optimal communication frequency and the corresponding optimal transmitting antenna height , optimal receiving antenna height , optimal elevation angle of transmitting antenna , and optimal elevation angle of receiving antenna .

[0017] Through the above technical solution, a method for dynamically adjusting over-the-horizon communication parameters based on evaporation duct provided by the present invention has the following beneficial effects: 1. By obtaining meteorological and hydrological parameters in real time on the observation platform and dynamically calculating the atmospheric modified refractive index profile in combination with the evaporation duct model, the present invention can accurately identify the characteristics of the evaporation duct, and then realize the precise derivation of key propagation parameters such as the lowest trapping frequency, critical incident angle, and antenna height. On this basis, the transmitting platform can calculate the optimal communication frequency and system antenna parameters in real time; 2. The present invention uses the particle swarm optimization algorithm to jointly optimize the key parameters of the communication system (including communication frequency, antenna height, and elevation angle), and determine the optimal communication frequency and antenna configuration parameters. In the multi-dimensional search space, through the global and local search mechanisms of the particle swarm, the propagation loss is effectively minimized, thereby improving the received power and signal-to-noise ratio, and enhancing the stability and reliability of the communication link; 3. Through the antenna servo system equipped on the transmitting and receiving platforms, the antenna parameters of the receiving platform can be accurately adjusted according to the parameters such as antenna height, elevation angle, longitude, and latitude updated in real time on the transmitting platform, and the dynamic alignment of the dual-end link can be realized. Through this real-time cooperation mechanism, the adaptability and deployment efficiency of the communication system in a complex marine environment are significantly enhanced; This method has the advantages of strong real-time performance, simple implementation, and flexible deployment, providing a solid support for building an efficient and reliable over-the-horizon communication system at sea. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0019] Figure 1 It is a schematic flow chart of a method for dynamically adjusting over-the-horizon communication parameters based on evaporation duct disclosed in an embodiment of the present invention; Figure 2 It is a schematic diagram of a particle swarm optimization algorithm disclosed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

[0021] The present invention provides a method for dynamically adjusting over-the-horizon communication parameters based on evaporation duct, as Figure 1 shown, including the following steps:

[0022] Step 1: Acquisition of observation data: Install meteorological and hydrological sensors at a specified height on the offshore transmitting platform to obtain meteorological and hydrological data at the specified height.

[0023] Install a barometric pressure sensor, a temperature and humidity sensor, an ultrasonic three-dimensional wind sensor, and an infrared sensor at a specified height on a ship-based launch platform or a buoy. Calibrate all sensors before and after installation to obtain the barometric pressure, atmospheric temperature, relative humidity, wind speed, and sea surface temperature at the specified height.

[0024] The transmitting end of the over-the-horizon communication system is an offshore launch platform, including a ship-based launch platform or a buoy. The receiving end can be a ship-based launch platform or a buoy, or it can also be a shore-based platform.

[0025] Step 2: Obtaining the atmospheric modified refractive index profile: Use the obtained meteorological and hydrological data at the specified height to calculate the diagnostic value of the evaporation duct height through an evaporation duct model; use the logarithmic linear function of the atmospheric modified refractive index profile with respect to the evaporation duct height to obtain the corresponding atmospheric modified refractive index profile.

[0026] The evaporation duct models include the PJ, NPS, BYC, NWA, LKB, or NRL models, all of which are existing known models.

[0027] The calculation of the atmospheric modified refractive index is as follows: ; In the formula: is the atmospheric modified refractive index at a height of 0 m, is the height, is the atmospheric modified refractive index at a height of z, = 0.00015 m, is the evaporation duct height.

[0028] Step 3: Obtaining the lowest trapped frequency and the critical incident angle: According to the obtained atmospheric modified refractive index profile, calculate its refractive index gradient and the evaporation duct height to obtain the lowest trapped frequency in the current environment; at the same time, calculate the duct strength according to the modified refractive index profile to further obtain the critical incident angle.

[0029] The lowest trapped frequency is calculated as follows: ; In the formula, is the atmospheric modified refractive index, is the height, is the evaporation duct height.

[0030] The critical incident angle Its expression is as follows: ; In the formula, is the duct strength, , is the atmospheric modified refractive index at a height of 0 m, is the minimum value of the atmospheric modified refractive index.

[0031] Step 4: Determine the communication frequency range and the range of antenna parameters at the transmitter and receiver according to the lowest trapping frequency, the critical incident angle, the evaporation duct height, and empirical values.

[0032] The antenna parameters of the transmitting platform and the receiving platform include the transmitting antenna height , the receiving antenna height , the elevation angle of the transmitting antenna , and the elevation angle of the receiving antenna .

[0033] To ensure the formation of an evaporation duct over-the-horizon communication link, the communication frequency should satisfy: ; Combined with the empirical values, the determined communication frequency range is , where is the lowest trapping frequency, is 12.5 GHz.

[0034] This angle is the maximum elevation angle allowed for electromagnetic waves to enter and maintain waveguide propagation in the current atmospheric structure. The actual transmission elevation angle of the electromagnetic wave should satisfy: ; Finally, to form a stable waveguide propagation path, the transmitting antenna height should satisfy: ; To ensure that the initial path of the electromagnetic wave is within the waveguide capture range.

[0035] The range of antenna parameters determined in combination with empirical values is: , the receiving antenna height , the elevation angle of the transmitting antenna , the elevation angle of the receiving antenna , is the evaporation duct height, is the critical incident angle.

[0036] Step 5: Use the particle swarm optimization algorithm to search within the communication frequency range and the range of antenna parameters to obtain the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration.

[0037] First, calculate the link distance based on the longitude and latitude information of the transmitting platform and the receiving platform: ; where is the radius of the Earth, are the latitudes of the transmitter and receiver, respectively, expressed in radians; are the longitudes of the transmitter and receiver, respectively, expressed in radians; is the longitude difference between the transmitter and receiver; Secondly, construct the propagation loss function : ; In the formula: is the antenna height; is the electromagnetic wave frequency; is the distance in the horizontal direction; M is the atmospheric correction refractive index profile; is the propagation factor, which is a function of the transmitter antenna frequency, antenna height, antenna elevation angle, link distance, and atmospheric correction refractive index profile, and can be calculated by the parabolic equation method, with the unit of V / m; Then, according to the determined link distance and the loss function Use the particle swarm optimization algorithm as shown in Figure 2 for optimization, and the specific method is as follows: (1) Parameter initialization, set the particle swarm size and the maximum number of iterations , define the multi-dimensional search parameter space, including the following variables: communication frequency , transmitter antenna height , receiver antenna height , transmitter antenna elevation angle , receiver antenna elevation angle ; For each particle randomly initialize its position vector and velocity vector in the above five-dimensional search space; (2) Calculate the fitness. Under the condition that the propagation loss is the smallest and the distance in the horizontal direction is the link distance between the transmitter platform and the receiver platform, design the fitness function as: ; (3) Update the particle velocity and position, and perform individual optimal and global optimal guidance; ; Among them, is the inertia weight, represents the velocity vector of the th particle at the th iteration, represents the th particle at the The position vector at the th iteration, indicating the velocity of the th particle at the th iteration, indicating the updated position of the th particle after the th iteration; are the individual and swarm learning factors, with a value range of ; is a uniformly random number between and ; is the historical best position of the th particle at the th iteration; ; that is, find the frequency point with the minimum propagation loss in the search space and output the optimal communication frequency and the corresponding optimal transmitting antenna height , the optimal receiving antenna height , the optimal transmitting antenna elevation angle , and the optimal receiving antenna elevation angle .

[0038] The transmitting platform continuously collects meteorological and hydrological data in the current environment, including temperature, humidity, air pressure, wind speed, sea surface temperature, etc., and updates the atmospheric correction refractive index profile in real time based on the latest data. Combining the waveguide structure parameters with the communication link requirements, the optimal communication frequency and the transmitting and receiving antenna heights and elevation angles are dynamically calculated according to the above process to adapt to the current evaporation duct propagation conditions.

[0039] Through the embedded data transmission module, the latitude and longitude of the transmitting platform , as well as the receiving antenna height and the receiving antenna elevation angle calculated in real time by the transmitting platform are sent to the receiving platform in real time. Based on the received receiving antenna height and the receiving antenna elevation angle , the receiving end is adjusted through the antenna servo system, and combined with its own latitude and longitude information, the azimuth angle of the receiving antenna is calculated in real time, so as to complete the precise adjustment of the antennas at the transmitting and receiving ends. The azimuth angle of the transmitting platform and the azimuth angle of the receiving platform are in opposite directions, so the azimuth angle of the receiving end can be obtained by reversing the azimuth angle of the transmitting end: ; This mechanism ensures that in a complex marine evaporation duct environment, both communication parties can quickly adjust antenna parameters according to environmental changes and maintain stable coupling of the waveguide propagation path.

[0040] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for dynamically adjusting over-the-horizon communication parameters based on evaporation ducts, characterized in that It includes the following steps: Step 1, acquisition of observation data: Install meteorological and hydrological sensors at a specified height on an offshore launch platform to obtain meteorological and hydrological data at the specified height; Step 2, acquisition of the atmospheric modified refractive index profile: Use the obtained meteorological and hydrological data at the specified height to calculate the diagnostic value of the evaporation duct height through an evaporation duct model; Use the logarithmic linear function of the atmospheric modified refractive index profile with respect to the evaporation duct height to obtain the corresponding atmospheric modified refractive index profile; Step 3, acquisition of the lowest trapping frequency and the critical incident angle: According to the obtained atmospheric modified refractive index profile, calculate its refractive index gradient and evaporation duct height to obtain the lowest trapping frequency in the current environment; At the same time, calculate the duct strength according to the modified refractive index profile to further obtain the critical incident angle; Step 4, determine the communication frequency range and the antenna parameter ranges of the transmitting end and the receiving end according to the lowest trapping frequency, the critical incident angle, the evaporation duct height and empirical values; Step 5, adopt the particle swarm optimization algorithm to search within the communication frequency range and the antenna parameter ranges to obtain the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration.

2. The dynamic adjustment method for over-the-horizon communication parameters based on evaporation duct according to claim 1, wherein The meteorological and hydrological data in Step 1 include the observation data of air pressure, atmospheric temperature, relative humidity, wind speed and sea surface temperature.

3. A method for dynamically adjusting over-the-horizon communication parameters based on evaporation duct according to claim 1, characterized in that The evaporation duct models in Step 2 include the PJ, NPS, BYC, NWA, LKB or NRL models.

4. A method for dynamically adjusting over-the-horizon communication parameters based on evaporation ducts according to claim 1, characterized in that In Step 2, the atmospheric modified refractive index is calculated as follows: ； In the formula: is the atmospheric modified refractive index at a height of 0 m, is the height, is the atmospheric modified refractive index at height z, = 0.00015 m, is the evaporation duct height.

5. The dynamic adjustment method for over-the-horizon communication parameters based on evaporation duct according to claim 1, wherein In Step 3, the lowest trapping frequency is calculated as follows: ； In the formula, is the atmospheric modified refractive index, is the altitude, is the evaporation duct height.

6. The dynamic adjustment method for over-the-horizon communication parameters based on evaporation duct according to claim 1, wherein In step three, the critical incident angle Its expression is as follows: ； In the formula, is the waveguide strength, , is the atmospheric modified refractive index at a height of 0 m, is the minimum value of the atmospheric modified refractive index.

7. A method for dynamically adjusting over-the-horizon communication parameters based on evaporation ducts according to claim 5, characterized in that In Step 4, the determined communication frequency range is , where is the lowest trapping frequency, and is 12.5 GHz.

8. A method for dynamically adjusting the parameters of over-the-horizon communication based on evaporation duct, according to claim 7, characterized in that In Step 4, the antenna parameters of the transmitter and the receiver include the transmitting antenna height , the receiving antenna height , the transmitting antenna elevation angle and the receiving antenna elevation angle . The determined range of antenna parameters is: the transmitting antenna height , the receiving antenna height , the transmitting antenna elevation angle , the receiving antenna elevation angle , is the evaporation duct height, is the critical incident angle.

9. A method for dynamically adjusting the parameters of over-the-horizon communication based on evaporation ducts according to claim 8, characterized in that The specific method of Step 5 is as follows: First, calculate the link distance based on the latitude and longitude information of the transmitting platform and the receiving platform : ； wherein, is the radius of the earth, are the latitudes of the transmitting end and the receiving end, respectively, expressed in radians; are the longitudes of the transmitting end and the receiving end, respectively, expressed in radians; is the longitude difference between the transmitting end and the receiving end; Secondly, construct the propagation loss function : ； In the formula: is the antenna height; is the electromagnetic wave frequency; is the distance in the horizontal direction; M is the atmospheric correction refractive index profile; is the propagation factor, which is a function of the transmitting antenna frequency, antenna height, antenna elevation angle, link distance, and atmospheric correction refractive index profile, and can be calculated by the parabolic equation method, with the unit of V / m; Then, according to the determined link distance and the loss function perform optimization using the particle swarm optimization algorithm, and output the communication frequency with the minimum propagation loss and the optimal antenna parameter configuration.

10. A method for dynamically adjusting over-the-horizon communication parameters based on evaporation ducts according to claim 9, characterized in that The specific method of optimization using the particle swarm optimization algorithm is as follows: (1) Parameter initialization, setting the particle swarm size and the maximum number of iterations to define a multi-dimensional search parameter space Including the following variables: communication frequency , transmitting antenna height , receiving antenna height , transmitting antenna elevation angle , receiving antenna elevation angle ; For each particle randomly initialize its position vector and velocity vector in the above five-dimensional search space (2) Calculate the fitness with the minimum propagation loss and the distance in the horizontal direction being the link distance between the transmitting platform and the receiving platform Under the condition that, design the fitness function as: ； (3) Update the particle velocity and position, and conduct individual optimal and global optimal guidance; ； Among them, is the inertia weight, represents the velocity vector of the -th particle at the -th iteration, represents the position vector of the -th particle at the -th iteration, represents the velocity of the -th particle at the -th iteration, represents the updated position of the -th particle after the -th iteration, are the individual and swarm learning factors, and the value range is is a uniformly random number between, is the historical best position of particle at the -th iteration, is the global best position of the current swarm at the -th iteration; (4) Repeat Step (2) and Step (3) until the termination condition is reached, and output the optimal parameter combination of the final particle swarm: ； That is, find the frequency point with the minimum propagation loss within the search space and output the optimal communication frequency and the corresponding optimal transmitting antenna height , the optimal receiving antenna height , the optimal transmitting antenna elevation angle , and the optimal receiving antenna elevation angle .

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