Non-uniform evaporation waveguide height inversion method based on bidirectional X-waveband signals
By employing a bidirectional X-band signal non-uniform evaporating waveguide height inversion method, the problem of low inversion accuracy in existing technologies has been solved, achieving high-precision non-uniform evaporating waveguide height inversion and supporting over-the-horizon detection and early warning of marine electromagnetic systems.
Patent Information
- Application Number
- CN202511868939.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-03-17
AI Technical Summary
Existing methods for inverting the height of non-uniform evaporating waveguides only obtain the channel characteristics of a one-way link, resulting in low time resolution, limited data, and a limited reflection of the channel characteristics of non-uniform evaporating waveguides. These methods cannot meet the requirements of over-the-horizon radio wave propagation in maritime electromagnetic systems.
A non-uniform evaporating waveguide height inversion method for bidirectional X-band signals is adopted. By deploying channel monitoring equipment on both communicating parties, channel level data is collected synchronously. The measured path loss is calculated in combination with system parameters, and the simulated path loss is calculated using the evaporating waveguide profile model and the radio wave propagation model. An optimization algorithm is used to search for the optimal height distribution.
It significantly improves the accuracy and reliability of inversion of non-uniform evaporation waveguide height, meets the over-the-horizon detection and early warning requirements of maritime radar and communication systems, and enhances the accuracy and coverage of inversion.
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Figure CN121683501A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of radar, and particularly relates to a non-uniform evaporation duct height inversion method based on bidirectional X-band signals. BACKGROUND
[0002] Evaporation duct is a common type of atmospheric waveguide at sea, and the dynamic changes of sea-air parameters will cause the non-uniform distribution of evaporation duct height in time and space dimensions, affecting the propagation path, signal strength and quality of the electric wave, and causing problems such as radar detection blind area and ship positioning and tracking failure. Therefore, accurately grasping the non-uniform evaporation duct height distribution is crucial for the design and reliability of the electromagnetic system of the radar at sea.
[0003] At present, the mainstream non-uniform evaporation duct height inversion methods include radar sea clutter inversion, occultation inversion, path loss inversion and the like, which estimate the non-uniform evaporation duct height distribution by evaluating the influence of the vertical or horizontal changes of the evaporation duct refractive index structure on the spatial electromagnetic field distribution when the electromagnetic wave propagates forward. However, the existing methods only obtain the channel characteristics of a single link, and have low time resolution, single data and limited reflection of the non-uniform evaporation duct channel characteristics. Therefore, there is an urgent need for a high-precision non-uniform evaporation duct height inversion method capable of obtaining rich channel characteristics to meet the over-the-horizon wave propagation requirements of the electromagnetic system at sea and provide reliable decision support for the over-the-horizon detection and early warning of the radar system. SUMMARY
[0004] In order to overcome the deficiencies of the prior art, the application provides a non-uniform evaporation duct height inversion method based on bidirectional X-band signals, which relies on the channel monitoring equipment deployed by both parties of communication, synchronously collects and records the channel level data of the signals from the opposite end, calculates the measured path loss of the bidirectional link in combination with the system parameters, and calculates the simulated path loss of the bidirectional link using the evaporation duct profile model and the wave propagation model. Then, the target function is constructed based on the measured path loss and the simulated path loss of the bidirectional link, and an optimization algorithm is used to search for the optimal set of non-uniform evaporation duct heights. The application effectively improves the inversion accuracy and reliability of the non-uniform evaporation duct height, and provides key technical support for the design and application of the electromagnetic system such as the radar and communication at sea.
[0005] The technical solution adopted by the application to solve the technical problems is as follows: Step 1: Establish a non-uniform evaporation duct channel monitoring link and clearly define the forward and reverse link directions, deploy the peer channel monitoring equipment at both ends of the link, synchronously collect and record the channel level data of the bidirectional X-band signals, and record the latitude and longitude, monitoring time and system parameter information of the channel monitoring equipment at the same time; Step 2: Calculate the link length according to the latitude and longitude information of the channel monitoring device; calculate the measured path loss of the dual-direction X-band wave propagation according to the system parameters and the channel level data of the dual-direction X-band; Step 3: Establish the initial non-uniform evaporation waveguide height on the forward monitoring link , Substitute the evaporation waveguide profile model to obtain a set of non-uniform evaporation waveguide correction refractive index profiles at different distances; Step 4: Substitute the non-uniform evaporation waveguide correction refractive index profile and the system parameters of the monitoring device into the electromagnetic wave propagation model to calculate the simulation path loss of the dual-direction X-band wave propagation; Step 5: Use the objective function to evaluate the degree of conformity between the measured path loss and the simulation path loss; Step 6: Use the optimization algorithm to search for the optimal set of non-uniform evaporation waveguide height distribution on the radio wave propagation link.
[0006] Preferably, the calculation formula of the evaporation waveguide correction refractive index profile is: (1) In the formula, , are the atmospheric correction refractive indexes at the sea surface and the height z , is the evaporation waveguide height, and the roughness length ; Preferably, the optimization algorithm is a Bayesian optimization algorithm, which approaches the optimal solution of the objective function through multiple iterations to obtain the optimal set of non-uniform evaporation waveguide heights; the updating process of the non-uniform evaporation waveguide height is as follows: (2) (3) In the formula, is the next evaluation point of the non-uniform evaporation waveguide height, represents the observed data set, is the input space formed by the search interval, represents the posterior distribution of the observed data set, and the parameter is used to balance the mean and variance, and is set according to the required confidence level; represents the mean of the non-uniform evaporation waveguide height, represents the variance of the non-uniform evaporation waveguide height.
[0007] An electronic device comprises a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to enable the electronic device to perform the above-mentioned non-uniform evaporation waveguide height inversion method.
[0008] A computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the above-mentioned non-uniform evaporation waveguide height inversion method.
[0009] A chip comprising a processor for calling and running a computer program from a memory to enable a device installed with the chip to perform the above-mentioned non-uniform evaporation waveguide height inversion method.
[0010] A computer program product comprising a computer storage medium storing a computer program, the computer program comprising instructions executable by at least one processor, the instructions being executed by the at least one processor to implement the above-mentioned non-uniform evaporation waveguide height inversion method.
[0011] The beneficial effects of the present application are as follows: 1. The present application synchronously collects and records bidirectional radio wave propagation signals, calculates bidirectional measured path losses in combination with system parameters, and calculates bidirectional simulated path losses by using an evaporation waveguide correction refractive index profile and a radio wave propagation model. Subsequently, a target function is constructed using bidirectional measured and simulated path losses, and an optimal set of non-uniform evaporation waveguide heights is searched and solved in combination with an optimization algorithm. The present application effectively improves the inversion accuracy and reliability of non-uniform evaporation waveguide heights, and provides key technical support for the design and application of electromagnetic systems such as marine radars and communication systems.
[0012] 2. The present application overcomes the problems of single path loss data and limited evaporation waveguide channel characteristics of existing inversion methods by using the radio wave propagation characteristics of signals in the same link and different propagation directions, significantly improving the accuracy of the non-uniform evaporation waveguide height inversion method.
[0013] 3. The present application uses a Bayesian optimization algorithm, which can effectively avoid falling into local optimal and converging to a global optimal solution, significantly improving the accuracy and efficiency of non-uniform evaporation waveguide height inversion.
[0014] 4. By using the commonly used over-the-horizon X-band signals on ships, in combination with widely distributed marine ships and shore-based communication nodes, the present application can improve the coverage range and spatio-temporal resolution of marine non-uniform evaporation waveguide height inversion, realize long-term real-time, efficient and high-precision inversion of non-uniform evaporation waveguide heights in a large range of sea area, and provide reliable decision support for over-the-horizon working requirements of marine electromagnetic systems, over-the-horizon detection and early warning of radar systems. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 is a general flow chart of the method of the present application; Figure 2 is a photograph of the evaporation duct experimental site and equipment during the experiment of the embodiment of the present application, Figure 2(a) is an experimental link, Figure 2(b) is S1, and Figure 2(c) is S2; Figure 3 is a channel level value measurement flow chart of the bidirectional X-band non-uniform evaporation duct of the embodiment of the present application; Figure 4 is a bidirectional path loss distribution schematic diagram of the X-band signal of the embodiment of the present application; Figure 5 is an inversion result and a calculation result comparison of the non-uniform evaporation duct height at a monitoring point of the embodiment of the present application, Figure 5(a) is an S1 monitoring point, and Figure 5(b) is an S2 monitoring point. DETAILED DESCRIPTION
[0016] The present application is further described below in conjunction with the drawings and embodiments.
[0017] The traditional non-uniform evaporation duct height inversion method uses a single direction path loss for inversion, and the reflected evaporation duct channel characteristics are limited and the inversion precision is low. To solve this problem and obtain more non-uniform evaporation duct channel characteristics and realize high-precision inversion of the non-uniform evaporation duct height, the present application proposes a non-uniform evaporation duct height inversion method based on bidirectional X-band signals. Relying on the channel monitoring equipment deployed by both sides of the communication, the level data of the X-band signals in different propagation directions on the same link are synchronously collected and recorded, the bidirectional measured path loss is calculated in combination with the system parameters, and the bidirectional simulation path loss is calculated using the evaporation duct profile model and the radio wave propagation model. Then, the objective function is constructed based on the measured path loss and the simulation path loss, and an optimal set of non-uniform evaporation duct heights is searched and solved using an optimization algorithm, thereby realizing high-precision inversion of the non-uniform evaporation duct height and meeting the over-the-horizon radio wave propagation requirement of the marine electromagnetic system and providing reliable decision support for over-the-horizon detection and early warning of the radar system.
[0018] The method of the present application relies on the channel monitoring equipment deployed by both sides of the communication, synchronously collects and records the channel level data of the signals from the opposite end, calculates the bidirectional measured path loss in combination with the system parameters, and calculates the bidirectional simulation path loss using the evaporation duct profile model and the radio wave propagation model. Then, the objective function is constructed based on the bidirectional measured path loss and the simulation path loss, and an optimal set of non-uniform evaporation duct heights is searched and solved using an optimization algorithm. The specific steps are as follows: Step 1: Establish a non-uniform evaporating waveguide channel monitoring link and determine its forward and reverse link directions. Deploy equivalent channel monitoring equipment at both ends of the link, synchronously collect and record the channel level data of the X-band signals in both directions, and record information such as the latitude and longitude of the channel monitoring equipment, monitoring time, and system parameters.
[0019] Step 2: Calculate the link length based on the latitude and longitude information from the channel monitoring equipment. Calculate the measured path loss of X-band radio wave propagation in both directions based on the system parameters and the channel level data of the X-band in both directions.
[0020] Step 3: Establish the initial non-uniform evaporation waveguide height on the forward monitoring link ,Will Substituting the evaporation waveguide profile model, we obtain a set of corrected refractive index profiles of non-uniform evaporation waveguides at different distances.
[0021] Step 4: Substitute the modified refractive index profile of the non-uniform evaporation waveguide and the system parameters of the monitoring equipment into the electromagnetic wave propagation model to calculate the simulated path loss of bidirectional X-band radio wave propagation.
[0022] Step 5: Use the objective function to evaluate the degree of agreement between the measured bidirectional path loss and the simulated path loss.
[0023] Step 6: Use an optimization algorithm to search for the optimal set of non-uniform evaporation waveguide height distributions on the radio wave propagation link.
[0024] The signal used in this invention is the X-band signal commonly used on ships.
[0025] The formula for calculating the corrected refractive index profile of an evaporating waveguide is as follows: (1) In the formula, , Sea level and altitude, respectively z Atmospheric corrected refractive index at that location Here is the height of the evaporation waveguide and the roughness length. , The intensity is the evaporation waveguide strength.
[0026] The optimization algorithm is a Bayesian optimization algorithm, which approximates the optimal solution of the objective function through multiple iterations to obtain an optimal set of non-uniform evaporation waveguide heights. The update process is as follows: (2) (3) In the formula, This is the next evaluation point for the height of the non-uniform evaporation waveguide. This indicates the observed dataset. It is the input space formed by the search interval. Represents the posterior distribution of the observed dataset, with parameters Used to balance the mean and variance, set according to the required confidence level.
[0027] Example: Figure 1 The following is a general flowchart of a method for inverting the height of a non-uniform evaporating waveguide based on bidirectional X-band signals, implemented through the following specific embodiments: The experimental site for this example was selected in the Bohai Sea. The experimental site and monitoring equipment are shown in Figure 2. The measurement procedure for the channel level of the bidirectional X-band non-uniform evaporating waveguide is as follows: Figure 3 As shown, S1 and S2 represent the locations of the monitoring equipment. The link transmitted by S1 and received by S2 is defined as the forward propagation link, denoted as S1S2; the reverse propagation link is S2S1, i.e., S2 transmits and S1 receives. P1, P2 and P3 represent the ERA5 grid points traversed by the link. The automatic weather stations of S1 and S2 are installed at a height of 6 m.
[0028] In this example, the transmit and receive antennas of links S1 and S2 are both omnidirectional antennas, each with a height of 6 m and an antenna gain of 7 dBi. The transmit and receive antennas of links S2 and S1 are both horn antennas, each with a height of 5.5 m and an antenna gain of 20 dBi. All antennas are vertically polarized, with a transmit gain of 40 dBi and a low-noise amplifier gain of 35 dBi. The system loss of the link is 5 dB, the radio signal frequency is 8000.5 MHz, and the link length between S1 and S2 is 111 km.
[0029] Step 1: Use channel monitoring equipment to synchronously collect and record the channel level data of the X-band signal at the other end, and at the same time record the latitude and longitude, monitoring time and system parameters of the S1 and S2 channel monitoring equipment.
[0030] Step 2: Calculate the link length for radio wave propagation based on the latitude and longitude information from the channel monitoring equipment. Calculate the measured path loss for radio wave propagation in the directions of link S1S2 and link S2S1 based on the system parameters and the channel level data of the X-band in both directions. , Two-way measured path loss data as follows Figure 4 As shown. Figure 4 As shown, from the entire sampling interval of the comparative verification, the path loss data of link S1S2 has a similar trend to that of link S2S1.
[0031] Step 3: Establish the initial non-uniform evaporation waveguide height in the S1S2 direction on the monitoring link. ,Will Substituting into formula (4), the modified refractive index profile of the non-uniform evaporation waveguide in the S1S2 and S2S1 directions of the link is calculated. , .
[0032] (4) In the formula, , Sea level and altitude, respectively z Atmospheric corrected refractive index at that location Take 330; Here is the height of the evaporation waveguide and the roughness length. , The intensity is the evaporation waveguide strength.
[0033] Step 4: Substitute the corrected refractive index profile of the non-uniform evaporation waveguide and the system parameters of the monitoring equipment into the electromagnetic wave propagation model to calculate the simulated path loss of the X-band signal propagation in the S1S2 and S2S1 directions. , .
[0034] Step 5: Use the objective function To evaluate the agreement between the measured bidirectional path loss and the simulated path loss, the objective function is expressed as follows: (5) Step 6: Use the Bayesian optimization algorithm to search for the optimal set of non-uniform evaporation waveguide heights. The update process for the height of a non-uniform evaporation waveguide is as follows: (6) (7) In the formula, This is the next assessment point. This indicates the observed dataset. It is the input space formed by the search interval. Represents the posterior distribution of the observed dataset, with parameters It is used to balance the mean and variance, and is usually set according to the required confidence level.
[0035] Figure 5 shows the inversion results of the non-uniform evaporation guide height at monitoring points S1 and S2 during the experiment. To verify the accuracy of the method of the present invention, this example uses the measured meteorological parameters at monitoring points S1 and S2, the sea surface temperature data at reanalysis grid points P1 and P3, and the evaporation guide profile model to obtain the calculated value of the evaporation guide height as the true value for comparison and verification.
[0036] As shown in Figure 5, due to the spatiotemporal non-uniformity of the distribution of evaporation waveguides at sea, there are significant differences in the inversion results of evaporation waveguide heights at monitoring points S1 and S2 during the experiment. Furthermore, compared with the calculated evaporation waveguide height, the root mean square error (RMSE) of the inversion result at monitoring point S1 is 1.60 m, and the RMS error at monitoring point S2 is 2.04 m, verifying the accuracy of the non-uniform evaporation waveguide height inversion method based on bidirectional X-band signals.
Claims
1. A method for retrieving the height of a non-uniform evaporation duct based on two-way X-band signals, characterized in that, The method comprises the following steps: Step 1: Establishing a non-uniform evaporation waveguide channel monitoring link and determining the forward and reverse link directions, deploying peer channel monitoring equipment at both ends of the link, synchronously collecting and recording the channel level data of the X-band signals in both directions, and recording the latitude and longitude of the channel monitoring equipment, monitoring time and system parameter information; Step 2: Calculating the link length according to the latitude and longitude information of the channel monitoring equipment, and calculating the measured path loss of the X-band signals in both directions according to the system parameters and the channel level data of the X-band signals in both directions; Step 3: Establishing initial non-uniform evaporation waveguide height on the forward monitoring link , the is substituted into the evaporation waveguide profile model to obtain a set of non-uniform evaporation waveguide correction refractive index profiles at different distances; Step 4: Substituting the non-uniform evaporation waveguide correction refractive index profile and the system parameters of the monitoring equipment into the electromagnetic wave propagation model to calculate the simulation path loss of the X-band signals in both directions; Step 5: Using the objective function to evaluate the degree of conformity between the measured path loss and the simulation path loss in both directions; Step 6: Using an optimization algorithm to search for a set of optimal non-uniform evaporation waveguide height distributions on the electromagnetic wave propagation link.
2. The method according to claim 1, wherein, The calculation formula of the evaporation waveguide correction refractive index profile is: (1) where , are the sea surface and the atmospheric refractive index at height z , is the evaporation duct height, the roughness length .
3. The method according to claim 1, wherein, The optimization algorithm is a Bayesian optimization algorithm, and an optimal set of non-uniform evaporation waveguide heights is obtained by multiple iterations to approach the optimal solution of the target function; the non-uniform evaporation waveguide heights The updating process is as follows: (2) (3) wherein is the next evaluation point of the non-uniform evaporation waveguide height, denotes the observed data set, is the input space formed by the search interval, denotes the posterior distribution of the observed data set, the parameters is used to balance the mean and the variance, set according to the desired confidence level; denotes the mean of the non-uniform evaporation waveguide height, denotes the variance of the non-uniform evaporation waveguide height.
4. An electronic device, comprising: It comprises: A processor and a memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the method according to any one of claims 1 to 3.
5. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the method according to any one of claims 1 to 3.
6. A chip, characterized by It comprises: A processor is used to call and run a computer program from a memory, so that the device installed with the chip executes the method according to any one of claims 1 to 3.
7. A computer program product, characterised in that, The computer program product comprises a computer storage medium storing a computer program, and the computer program comprises instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the method according to any one of claims 1 to 3 is realized.