A waveguide / scattering mode discrimination method based on evaporation waveguide height

Abstract

The present invention discloses a method for distinguishing waveguide / scattering modes based on evaporation waveguide height. The method includes: setting an interval to which the evaporation waveguide height critical value belongs when the radio wave communication mode switches, and setting a threshold value for the interval length; using the midpoint of the interval as the initial value of the evaporation waveguide height critical value; judging whether the interval length exceeds the threshold value: if the interval length is greater than the threshold value, performing an iterative calculation; calculating the horizontal coordinate of the intersection of the radio wave propagation loss under the evaporation waveguide and tropospheric scattering modes; obtaining a final value of the critical value through iterative calculation; obtaining a predicted evaporation waveguide height value, and comparing it with the final value. If the predicted evaporation waveguide height value is less than the final value, it indicates tropospheric scattering; otherwise, it indicates evaporation waveguide. The present invention distinguishes the mode of over-the-horizon communication at sea based on the evaporation waveguide height critical value, is more adaptable to the continuous switching of communication modes, and provides guidance for adjusting and optimizing communication system parameters to improve performance.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of wireless communication technology, and more particularly to a waveguide / scattering mode discrimination method based on evaporation waveguide height. Background Art

[0002] In addition to satellite communications, evaporation ducts and tropospheric scattering are the two main ways to achieve beyond-horizon communications at sea. By making full use of evaporation ducts and tropospheric scattering, the parameters of the offshore beyond-horizon communication system can be adjusted and optimized, thereby improving the communication rate of the offshore high-speed beyond-horizon communication system.

[0003] The evaporation duct is caused by the evaporation and diffusion of water vapor on the sea surface. The atmospheric humidity above the sea surface decreases sharply with altitude, causing the radio waves to refract downward and propagate. The radio waves are trapped in the evaporation duct layer, greatly reducing the path loss of radio wave propagation and ultimately realizing beyond-line-of-sight communication at sea.

[0004] Tropospheric scatter refers to another way of achieving beyond-line-of-sight communication at sea by utilizing a large number of scatterers in the troposphere (mainly various vortex air masses, clouds, warm fronts, cold fronts, horizontal stratification, etc.) to refract and re-radiate microwaves and millimeter waves.

[0005] Due to complex weather conditions at sea, over-the-horizon communication at sea will constantly switch between evaporation ducts and tropospheric scattering. When the evaporation duct is high and the communication distance is short, over-the-horizon communication at sea is achieved through the evaporation duct; when the evaporation duct is low and the communication distance is long, over-the-horizon communication at sea is achieved through tropospheric scattering. Currently, existing models can only calculate radio wave propagation losses in either the evaporation duct or tropospheric scattering modes and cannot directly determine the current radio wave propagation mode based on the evaporation duct height. As a result, parameters such as the operating frequency and antenna height of the over-the-horizon communication system at sea cannot be adjusted and optimized in a timely manner based on the evaporation duct height, which in turn affects the system's communication speed.

[0006] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0007] It should be noted that this section is intended to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art by virtue of being included in this section. Summary of the Invention

[0008] The purpose of the embodiments of the present disclosure is to provide a waveguide / scattering mode discrimination method based on the evaporation waveguide height, thereby overcoming one or more problems caused by the limitations and defects of the related art at least to a certain extent.

[0009] The present disclosure provides a method for distinguishing waveguide / scattering modes based on the height of an evaporation waveguide, including:

[0010] Setting the interval to which the critical value of the evaporation waveguide height belongs when the radio wave communication mode is switched, and setting the threshold value of the interval length of the critical value of the evaporation waveguide height;

[0011] The midpoint of the interval to which the evaporation duct height critical value belongs is used as the initial value of the evaporation duct height critical value;

[0012] determining whether the interval length of the evaporation duct height critical value exceeds the threshold value: if the interval length of the evaporation duct height critical value is less than or equal to the threshold value, using the initial value as the final value of the evaporation duct height critical value; if the interval length of the evaporation duct height critical value is greater than the threshold value, performing iterative calculation on the evaporation duct height critical value;

[0013] When the communication distance at sea is greater than the limit distance of radio wave propagation, the horizontal coordinate of the intersection of the radio wave propagation loss in the evaporation duct mode and the radio wave propagation loss in the tropospheric scattering mode is calculated using the iteratively calculated critical value of the evaporation duct height and the communication system parameters;

[0014] According to the relationship between the horizontal coordinate and the communication distance at sea, a final value of the critical value of the evaporation duct height when the radio wave communication mode switches at the communication distance at sea is obtained through iterative calculation;

[0015] Meteorological data within the radio wave communication area is obtained and input into an evaporation duct height prediction model to obtain a predicted evaporation duct height value. The predicted evaporation duct height value is compared with the final value. If the predicted evaporation duct height value is less than the final value, it is determined that the current radio wave communication mode is a tropospheric scattering mode; otherwise, it is an evaporation duct mode.

[0016] In one embodiment of the present disclosure, the threshold value has a value range of less than or equal to 0.01.

[0017] In one embodiment of the present disclosure, a bisection method is used to iteratively calculate the critical value of the evaporation waveguide height.

[0018] In one embodiment of the present disclosure, the step of iteratively calculating, based on the magnitude relationship between the horizontal coordinate and the maritime communication distance, a final value of the critical value of the evaporation duct height when the radio wave communication mode switches at the maritime communication distance includes:

[0019] When the horizontal coordinate is greater than the offshore communication distance, the maximum value within the interval to which the evaporation duct height critical value belongs is set equal to the evaporation duct height critical value, so as to reduce the upper limit of the evaporation duct height critical value;

[0020] When the horizontal coordinate is less than the offshore communication distance, the minimum value in the interval to which the evaporation duct height critical value belongs is set to be equal to the evaporation duct height critical value, so as to increase the lower limit of the evaporation duct height critical value;

[0021] When the horizontal coordinate is equal to the offshore communication distance, the midpoint of the interval to which the evaporation duct height critical value belongs is taken as the final value of the evaporation duct height critical value.

[0022] In one embodiment of the present disclosure, the communication system parameters include: a communication system operating frequency, a transmitting antenna height, and a receiving antenna height.

[0023] In one embodiment of the present disclosure, the meteorological data includes: relative humidity, sea surface atmospheric pressure, sea surface temperature, air temperature above the sea surface, and wind speed component above the sea surface.

[0024] In one embodiment of the present disclosure, the determination method further includes:

[0025] The propagation loss is compared with the measured loss value to verify the discrimination accuracy of the discrimination method.

[0026] In one embodiment of the present disclosure, the determination method further includes:

[0027] The predicted evaporation duct height value is compared with the final value of the evaporation duct height critical value to verify the discrimination accuracy of the discrimination method.

[0028] The technical solutions provided by the embodiments of the present disclosure may have the following beneficial effects:

[0029] In the disclosed embodiments, a method for distinguishing between waveguide and scattering modes based on evaporation duct height is employed. This method utilizes communication system parameters and other factors to calculate a critical evaporation duct height value at which the waveguide / scattering mode switch occurs, and then uses this critical value to distinguish the mode of maritime beyond-line-of-sight communication. This method utilizes the calculated critical evaporation duct height value to better adapt to the continuous switching of maritime beyond-line-of-sight communication modes between evaporation duct and tropospheric scatter. This method provides guidance for adjusting and optimizing parameters such as transmit power, operating frequency, and transmit and receive antenna heights in maritime beyond-line-of-sight communication systems, enabling them to more fully utilize the evaporation duct to improve performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0031] Figure 1 A flow chart showing a method for distinguishing a waveguide / scattering mode based on the height of an evaporation waveguide in an exemplary embodiment of the present disclosure;

[0032] Figure 2 A flow chart showing a method for distinguishing a waveguide / scattering mode based on the height of an evaporation waveguide in another exemplary embodiment of the present disclosure is shown;

[0033] Figure 3 A schematic diagram showing an iterative process of critical value EDH at different communication distances in the 7960 MHz frequency band in an exemplary embodiment of the present disclosure is shown;

[0034] Figure 4 The following diagram shows the application effect of the exemplary embodiment of the present disclosure in the measured data of the 188km link on June 16, 2024;

[0035] Figure 5 The following diagram shows the application effect of the exemplary embodiment of the present disclosure in the measured data of the 188km link on June 18, 2024;

[0036] Figure 6 A diagram shows the application effect of an exemplary embodiment of the present disclosure in the actual measured data of a 188km link on June 19, 2024. DETAILED DESCRIPTION

[0037] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0038] In addition, the accompanying drawings are merely schematic illustrations of embodiments of the present disclosure and are not necessarily drawn to scale. Like reference numerals in the figures represent like or similar parts, and thus repeated descriptions thereof will be omitted. Some of the blocks shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically separate entities.

[0039] This example embodiment provides a waveguide / scattering mode discrimination method based on the evaporation waveguide height, please refer to Figure 1 The method includes: S101-S106. The details are as follows:

[0040] S101: Setting a range for the critical evaporation duct height value when switching to a radio wave communication mode, and setting a threshold for the length of the critical evaporation duct height range. The two endpoints of the critical evaporation duct height range are the minimum and maximum critical evaporation duct height values, respectively. Setting the threshold for the length of the critical evaporation duct height range is to set the threshold value as the difference between the maximum and minimum values ​​of the range. The threshold value is within a range of 0.01 or less.

[0041] S102: The midpoint of the interval to which the evaporation duct height critical value belongs is used as the initial value of the evaporation duct height critical value. The initial value is used as the starting value for subsequent iterative calculations of the evaporation duct height critical value.

[0042] S103, determining whether the interval length of the evaporation duct height critical value exceeds the threshold value: if the interval length of the evaporation duct height critical value is less than or equal to the threshold value, using the initial value as the final value of the evaporation duct height critical value; if the interval length of the evaporation duct height critical value is greater than the threshold value, performing iterative calculation on the evaporation duct height critical value.

[0043] S104: When the communication distance at sea exceeds the radio wave propagation limit, the abscissa of the intersection of the radio wave propagation loss in the evaporation duct mode and the radio wave propagation loss in the troposcatter mode is calculated using the iteratively calculated evaporation duct height critical value and communication system parameters. The communication system parameters include the communication system operating frequency, the transmit antenna height, the receive antenna height, and other parameters.

[0044] S105 , based on the relationship between the horizontal coordinate and the maritime communication distance, iteratively calculate a final value of the critical value of the evaporation duct height when the radio wave communication mode switches at the maritime communication distance. The final value ensures that the difference between the maximum and minimum values ​​of the interval to which it finally belongs is less than or equal to the threshold value.

[0045] S106: Acquire meteorological data within the radio wave communication area and input the meteorological data into an evaporation duct height prediction model to obtain a predicted evaporation duct height value. The predicted evaporation duct height value is compared with the final value. If the predicted evaporation duct height value is less than the final value, determine that the current radio wave communication mode is a tropospheric scatter mode; otherwise, determine that the current radio wave communication mode is an evaporation duct mode. The meteorological data includes relative humidity, sea surface atmospheric pressure, sea surface temperature, air temperature above the sea surface, and wind speed component above the sea surface.

[0046] In this embodiment, the communication system parameters are used to calculate the critical evaporation duct height at which the waveguide / scattering mode switches, and the maritime BLOCS communication mode is then determined based on this critical value. The discrimination method of this application utilizes the calculated critical evaporation duct height to better adapt to the continuous switching of maritime BLOCS communication modes between evaporation duct and tropospheric scatter. This provides guidance for adjusting and optimizing parameters such as transmit power, operating frequency, and transmit and receive antenna heights in maritime BLOCS communication systems, enabling them to more fully utilize the evaporation duct to improve performance.

[0047] The specific solutions of each step in the above embodiment are described below.

[0048] Please refer to Figure 1 and Figure 2 In S101, the range of the critical value of the evaporation waveguide height when the waveguide / scattering mode is switched is set [ , ],in, and are the minimum and maximum critical values ​​of the evaporation waveguide height respectively. The threshold value is .

[0049] In S102, the critical value of the evaporation waveguide height is updated by using the dichotomy method, and the interval [ , ] is taken as the initial value of the critical value of the evaporation waveguide height, and the calculation formula is as follows:

[0050] (1)

[0051] In S103, it is determined Does it exceed the given threshold? ,Right now:

[0052] (2)

[0053] If formula (2) holds true, the loop is exited and the initial value obtained in step S102 is output as the final value of the evaporation duct height critical value. If formula (2) does not hold true, the evaporation duct height critical value is iteratively calculated and the subsequent steps are continued.

[0054] In S104 , first, the radio wave propagation loss in the evaporation duct mode and the radio wave propagation loss in the troposcatter mode are calculated.

[0055] When calculating the radio wave propagation loss, the radio wave propagation model of the hybrid mode of evaporation duct and tropospheric scattering under over-the-horizon (please refer to CN119312581A) is used for calculation. In this model, when the communication distance at sea is dExceeding the limit distance of radio wave propagation under line-of-sight conditions l When , the above radio wave propagation loss is calculated using the following expression:

[0056] (3)

[0057] In formula (3), is the propagation loss of radio waves in the evaporation waveguide mode , radio wave propagation loss in tropospheric scatter mode Or within the line-of-sight range, apply the free space propagation model to calculate the free space radio wave propagation loss ; is the operating frequency of the communication system, in MHz; is the communication distance at sea; The radio wave propagation loss is calculated using the APM model (Advanced Propagation Model, APM, a commonly used model for calculating radio wave propagation path loss in evaporative duct environments) under evaporative duct conditions. and The maximum distance of radio wave propagation l The maximum value of the free space radio wave propagation loss at and the minimum value of the radio wave propagation loss calculated by using the APM model in the evaporation waveguide environment, both in dB; is the meteorological factor (dB); is the minimum scattering angle (mrad); is the exponential decay coefficient of tropospheric inhomogeneity intensity with height ( ; is the height from the lowest scattering point to the line connecting the receiving antenna and the transmitting antenna (km); is the height of the lowest scattering point above the ground (km); is the interface dielectric coupling loss (dB); and are the transmitting antenna gain and receiving antenna gain (dB) respectively.

[0058] Among them, in this model, the maximum distance of radio wave propagation is l The calculation formula (unit: km) is as follows:

[0059] (4)

[0060] in, and They represent the transmitting antenna height and the receiving antenna height respectively, both in meters.

[0061] The calculation formula is as follows:

[0062] (5)

[0063] in, is the spatial field quantity of the wave field, and They respectively represent the horizontal distance from the ground surface and the height from the ground surface, both in meters.

[0064] Secondly, the evaporation duct height critical value EDH and the maritime over-the-horizon communication system parameters (including operating frequency, transmitting and receiving antenna heights, etc.) updated in each iteration are input into the radio wave propagation model of the evaporation duct and tropospheric scattering mixed mode under over-the-horizon conditions to obtain the current and Intersection point horizontal coordinate . Then, enter S105.

[0065] S105 specifically includes the following steps S201 to S203:

[0066] S201, when the horizontal coordinate Greater than the maritime communication distance When , the maximum value in the interval to which the evaporation duct height critical value belongs is set to be equal to the evaporation duct height critical value, so as to reduce the upper limit of the evaporation duct height critical value. That is, when In order to make the horizontal coordinate of the intersection near d ,make , in order to narrow the upper limit of the critical value of the evaporation waveguide height, thereby lowering the critical value of the evaporation waveguide height.

[0067] S202, when the horizontal coordinate Less than the maritime communication distance When , the minimum value in the interval to which the evaporation duct height critical value belongs is set to be equal to the evaporation duct height critical value, so as to increase the lower limit of the evaporation duct height critical value. That is, when In order to make the horizontal coordinate of the intersection near d ,make , in order to increase the lower limit of the critical value of the evaporation waveguide height, thereby improving the critical value of the evaporation waveguide height.

[0068] S203, when the horizontal coordinate Equal to the maritime communication distance When , the midpoint of the interval to which the evaporation duct height critical value belongs is taken as the final value of the evaporation duct height critical value. When , the final value of the critical value EDH when the waveguide / scattering mode switches at a given communication distance is calculated by formula (2), and the iteration is stopped.

[0069] In S106, first, log in to the Global Forecast System (GFS) and download meteorological data for the required forecast time. By setting the longitude and latitude of the sea area where the offshore test link is located, extract meteorological data at the point closest to the link, including parameters such as relative humidity, sea surface atmospheric pressure, sea surface temperature, air temperature at 2 meters above the sea surface, and wind speed component at 10 meters above the sea surface. The extracted meteorological data is input into the Naval Postgraduate School model (NPS model) to calculate the atmospheric corrected refractive index profile within the range of 0-50 meters at the point closest to the offshore test link. The height corresponding to the minimum corrected refractive index is the predicted evaporation duct height value at the required forecast time.

[0070] Secondly, the predicted evaporation duct height value is compared with the final value. If the predicted evaporation duct height value is smaller than the final value, it is determined that the current radio wave communication mode is the tropospheric scattering mode, otherwise it is the evaporation duct mode.

[0071] In addition, the propagation loss may be compared with the measured loss value, and the predicted evaporation duct height value may be compared with the final value of the evaporation duct height critical value to verify the discrimination accuracy of the discrimination method.

[0072] The waveguide / scattering mode discrimination method based on the evaporation waveguide height of the present application is further described below through specific experimental examples.

[0073] 1. Set the critical value interval of the evaporation waveguide height when the waveguide / scattering mode switches to [8,13]. Set the threshold value .

[0074] 2. The midpoint of the interval [8,13], 10.5, is used as the initial value of the critical value of the evaporation waveguide height.

[0075] 3. The interval length 5 exceeds the threshold value, and the subsequent steps are continued.

[0076] 4. Input the evaporation duct height critical value EDH and the maritime over-the-horizon communication system parameters (including operating frequency, transmitting and receiving antenna heights, etc.) updated in each iteration into the radio wave propagation model of the evaporation duct and tropospheric scattering mixed mode under over-the-horizon conditions to obtain the current and Intersection point horizontal coordinate and compare it with the over-the-horizon communication distance at sea d In this embodiment, the over-the-horizon communication distance at sea is d It is 188km.

[0077] Please refer to Figure 3, after iterative calculation, different communication distances of 7960MHz frequency band are obtained ( Figure 3 (a) is 150km, Figure 3 (b) shows the final value of the critical EDH at 188 km. When the communication distance is 150 km, the critical EDH is 9.07812 m, and when the communication distance is 188 km, the critical EDH is 9.82297 m.

[0078] 5. Log in to the Global Forecast System (GFS), download the weather forecast data for June 16-19, 2024, and select the analysis area. , extract meteorological data in the area, including relative humidity, sea surface atmospheric pressure, sea surface temperature, air temperature 2 meters above the sea surface, and wind speed component 10 meters above the sea surface. The extracted meteorological data are input into the evaporation duct height prediction model (NPS model) to calculate the atmospheric corrected refractive index profile within the range of 0-50 meters at the nearest point to the offshore test link. The height corresponding to the minimum corrected refractive index is the predicted evaporation duct height value at the required forecast time.

[0079] The measured path loss data of the 7960MHz frequency band obtained on the 188km cross-sea test link from Yangxi, Guangdong to Wenchang, Hainan from June 16 to 19, 2024 was selected to verify the accuracy and applicability of the discrimination method described in the present invention. Figures 4 to 6 The following figure shows the effect of applying the discrimination method of the present invention to the measured data of a 188km link. Figures 4 to 6 The number of measured path loss samples are 60614, 27150 and 162152 respectively, and the total number of valid measured path loss samples is 249916.

[0080] 6. From Figure 4 It can be seen that in the 7960MHz frequency band, when the length of the offshore beyond-horizon communication link is 188km, the discrimination method of this application calculates the critical value EDH for waveguide / scattering switching to be 9.82297m. When the predicted evaporation duct height value is less than the critical value of 9.82297m, the offshore beyond-horizon communication mode is tropospheric scattering communication mode, and the predicted path loss does not change with the evaporation duct height value, showing a gentle and stable trend.

[0081] When the predicted evaporation duct height value is greater than the critical value of 9.82297m, the offshore beyond-line-of-sight communication mode is the evaporation duct communication mode. The predicted path loss gradually decreases with the increase of the evaporation duct height value. This simulation result is consistent with the measured path loss change trend, verifying the accuracy and applicability of the discrimination method described in the present invention.

[0082] Likewise, Figure 5 and Figure 6The accuracy of the discrimination method of the present invention is also verified. Figure 5 At 12:00 in the figure, the predicted evaporation duct height is 9.74m, which is lower than the critical value of 9.82297m. The over-the-horizon communication mode at sea changes from evaporation duct to tropospheric scattering. The predicted path loss gradually increases with the decrease of evaporation duct height, and gradually shows a stable trend, which is consistent with the change trend of the measured path loss. Figure 6 At 09:30, the predicted evaporation duct height is 10m, exceeding the critical value of 9.82297m. The over-the-horizon communication mode at sea switches from tropospheric scattering to evaporation duct. The predicted path loss gradually decreases with the increase of the evaporation duct height, which is consistent with the measured path loss change trend, verifying the accuracy of the discrimination method described in the present invention.

[0083] Compared with the existing technology, the present application only needs to calculate one height parameter, namely the critical value of the evaporation waveguide height when the radio wave communication mode is switched, to determine the radio wave communication mode, thereby improving the efficiency of communication system parameter adjustment and optimization, and thus improving the communication rate.

[0084] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A waveguide / scattering mode discrimination method based on the evaporation waveguide height, characterized in that: The discrimination method includes: Setting the interval to which the critical value of the evaporation waveguide height belongs when the radio wave communication mode is switched, and setting the threshold value of the interval length of the critical value of the evaporation waveguide height; The midpoint of the interval to which the evaporation duct height critical value belongs is used as the initial value of the evaporation duct height critical value; determining whether the interval length of the evaporation duct height critical value exceeds the threshold value: if the interval length of the evaporation duct height critical value is less than or equal to the threshold value, using the initial value as the final value of the evaporation duct height critical value; if the interval length of the evaporation duct height critical value is greater than the threshold value, performing iterative calculation on the evaporation duct height critical value; When the communication distance at sea is greater than the limit distance of radio wave propagation, the horizontal coordinate of the intersection of the radio wave propagation loss in the evaporation duct mode and the radio wave propagation loss in the tropospheric scattering mode is calculated using the iteratively calculated critical value of the evaporation duct height and the communication system parameters; According to the relationship between the horizontal coordinate and the communication distance at sea, a final value of the critical value of the evaporation duct height when the radio wave communication mode switches at the communication distance at sea is obtained through iterative calculation; Acquiring meteorological data within the radio wave communication area, inputting the meteorological data into an evaporation duct height prediction model to obtain a predicted evaporation duct height value, comparing the predicted evaporation duct height value with the final value, and determining that the current radio wave communication mode is a tropospheric scatter mode if the predicted evaporation duct height value is less than the final value, otherwise determining that the current radio wave communication mode is an evaporation duct mode; The step of iteratively calculating, based on the magnitude relationship between the horizontal coordinate and the maritime communication distance, a final value of the critical value of the evaporation duct height when the radio wave communication mode switches at the maritime communication distance comprises: When the horizontal coordinate is greater than the offshore communication distance, the maximum value within the interval to which the evaporation duct height critical value belongs is set equal to the evaporation duct height critical value, so as to reduce the upper limit of the evaporation duct height critical value; When the horizontal coordinate is less than the offshore communication distance, the minimum value in the interval to which the evaporation duct height critical value belongs is set to be equal to the evaporation duct height critical value, so as to increase the lower limit of the evaporation duct height critical value; When the horizontal coordinate is equal to the offshore communication distance, the midpoint of the interval to which the evaporation duct height critical value belongs is taken as the final value of the evaporation duct height critical value.

2. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The threshold value range is: less than or equal to 0.

01.

3. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The critical value of the evaporation waveguide height is iteratively calculated using a bisection method.

4. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The communication system parameters include: communication system operating frequency, transmitting antenna height and receiving antenna height.

5. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The meteorological data include: relative humidity, sea surface atmospheric pressure, sea surface temperature, air temperature above the sea surface and wind speed component above the sea surface.

6. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The discrimination method further comprises: The propagation loss is compared with the measured loss value to verify the discrimination accuracy of the discrimination method.

7. The waveguide / scattering mode discrimination method based on the evaporation waveguide height according to claim 1, characterized in that: The discrimination method further comprises: The predicted evaporation duct height value is compared with the final value of the evaporation duct height critical value to verify the discrimination accuracy of the discrimination method.

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