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Bi-directional parabolic equation method for accurately predicting propagation characteristics of low-frequency radio waves

A technology of radio wave propagation and parabolic equation, which is applied in the direction of electrical digital data processing, special data processing applications, instruments, etc., and can solve problems such as long time consumption, large error, and large calculation amount of FDTD method

Active Publication Date: 2017-11-10
XIAN UNIV OF TECH
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Problems solved by technology

[0003] The purpose of the present invention is to provide a two-way parabolic equation method for predicting the propagation characteristics of low-frequency radio waves with high precision, which can not only solve the shortcomings of the FDTD method, which has a large amount of calculation and takes a long time, but also solve the problems of the integral equation method and the parabolic equation method when the terrain fluctuates violently. The problem of large errors caused by ignoring the influence of backward wave propagation in

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  • Bi-directional parabolic equation method for accurately predicting propagation characteristics of low-frequency radio waves
  • Bi-directional parabolic equation method for accurately predicting propagation characteristics of low-frequency radio waves
  • Bi-directional parabolic equation method for accurately predicting propagation characteristics of low-frequency radio waves

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Embodiment 1

[0161] Prediction of Ground Field Strength in a Single Gaussian Mountain Range

[0162] The radiation power of the vertical electric dipole antenna is 1kW, and the signal source frequency is 100kHz. The total size of the calculation area is ρ max : 100km×z max : 102.4km, the grid division sizes are dρ=200m and dz=100m respectively, the initial distance ρ 0 =10km; ground electric parameter is εr =13, σ=3×10 -3 S / m (land); at center position ρ c = There is an isolated Gaussian peak at 50km, and its height function is

[0163]

[0164] l is 2km for the width of the mountain, H is the height of the mountain and 0.5km and 1.5km respectively. Fig. 2(a) and Fig. 2(b) respectively show the ground field strength comparison between the method of the present invention and the FDTD method in the case of a single Gaussian mountain range with the same width and different heights. From Figure 2(a) and Figure 2(b), it can be seen that the calculation results of the two methods are co...

Embodiment 2

[0166] Prediction of Ground Field Strength in Several Gaussian Mountains

[0167] Change the mountain peak in embodiment 1 into a plurality of Gaussian mountain terrains, the height of the first mountain peak is 1km, the width is 4km, and the center position is 40km; the height of the second mountain peak is 1.5km, the width is 2km, and the center position is 60km, other parameters remain unchanged. image 3 The ground field intensity comparison between the method of the present invention and the FDTD method is given in the case of multiple Gaussian mountain topography. Depend on image 3 It can be seen that for multiple Gaussian mountain terrains, the two-way parabolic equation method can also accurately predict the reciprocating reflection of waves between mountain peaks. And according to statistics, the calculation time of the FDTD method is 21 times that of the two-way parabolic equation method. Fig. 4 (a) and Fig. 4 (b) are respectively FDTD method and the space field ...

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Abstract

The present invention discloses a bi-directional parabolic equation method for accurately predicting the propagation characteristics of low-frequency radio waves. The method is specifically implemented according to the following steps: Step 1: inputting a model file; Step 2: calculating a forward initial field by using a ground plane formula; Step 3: combined with the forward initial field, based on the coordinate transformation model, using the distributed discrete Fourier transform algorithm to solve the forward field of the radio wave propagation at any position in the calculation area; Step 4: combined with the forward initial field, based on the ladder approximation model, using the SSFT algorithm to recursively solve the backward field due to terrain effects on the of radio wave propagation and the forward field due to multiple reflections; and Step 5: by combining the propagation field results in Step 3 and Step 4, solving the total magnetic field of the radio wave propagation. According to the method disclosed by the present invention, shortcomings of the large calculation amount and longtime consumption of the FDTD method can be solved, and the problem of large errors caused by neglecting the influence of backward wave propagation of the integral equation method and the parabolic equation method in the violent terrain fluctuation can be solved.

Description

technical field [0001] The invention belongs to the technical field of radio wave propagation, and in particular relates to a two-way parabolic equation method for predicting low-frequency radio wave propagation characteristics with high precision. Background technique [0002] Low-frequency radio waves are widely used in time service, navigation, communication and other fields because of their long wavelength, small signal propagation loss, and stable signal amplitude and phase. In order to improve the performance and accuracy of low-frequency radio engineering, it is necessary to study the variation law and prediction technology of low-frequency radio waves in various regions, time domains, and frequency domains. At present, the existing theoretical methods for predicting the propagation of low-frequency radio waves in complex environments include: integral equation method, parabolic equation method and finite-difference time-domain (Finite-Difference Time-Domain, FDTD) me...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/20
Inventor 席晓莉王丹丹张金生蒲玉蓉李征委
Owner XIAN UNIV OF TECH
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