CN107911185A - A kind of maximum usable frequency computational methods suitable for short-wave link during ionospheric storm - Google Patents

Abstract

The invention discloses a kind of maximum usable frequency computational methods suitable for short-wave link during ionospheric storm, include the following steps：Step 1, in China preferably 5 high-quality tiltedly surveyor's chain roads are as background link；Step 2, vertical survey data fof2, foE and M using domestic 14 electric wave observation stations（3000）The F2 factors；Step 3, obtain history ionospheric storm respectively during 3 of 5 background link midpoints hang down and survey data and oblique surveyor's chain road maximum usable frequency MUF data；Step 4, hang down link midpoint during the ionospheric storm that interpolation obtains in above-mentioned steps 3 and survey data as the input in ITU R P533 suggestion shortwave maximum usable frequency calculation formula.Maximum usable frequency computational methods disclosed in this invention suitable for short-wave link during ionospheric storm, the acquisition of short-wave link maximum usable frequency during ionospheric storm is realized using the method, P.533, short-wave link maximum usable frequency calculation formula is suggested based on ITU R, with reference to the ionosphere status information during ionospheric storm, a kind of maximum usable frequency computational methods suitable for short-wave link during ionospheric storm are established.

Description

A Calculation Method for the Highest Usable Frequency of HF Links During Ionospheric Storms

technical field

The invention relates to the technical fields of short-wave communication and radar, in particular to a method for calculating the highest available frequency of short-wave links during ionospheric storms.

Background technique

High-frequency radio signals emitted upward from the ground can be reflected by the ionosphere, which is the main mode of propagation of short-wave sky-wave signals. When high-frequency radio signals are reflected by the ionosphere, there is a maximum usable frequency (MUF) related to the reflected electron density. If the frequency is higher than this value, the radio waves will penetrate the ionosphere and never return to the ground. By interpreting the vertical ionization map and obtaining parameters such as fof2 and M(3000)F2 factors, the MUF reflected above the observation station on the 3000km path can be obtained. At the same time, the ionospheric oblique detection also realizes the short-wave detection between two points through the reflection of the ionosphere. It can be seen that the MUF of the short-wave link is closely related to the distribution of electron density in the ionosphere.

In recent years, the statistical properties of MUF and its prediction techniques have become mature when the ionosphere is calm. Among them, the ITU-R P.533 proposal recommended by the Radio Communication Group of the International Telecommunication Union is the most authoritative. Based on the reference ionosphere proposed by ITU-R P.1239, this proposal establishes a shortwave link parameter prediction method through ray path analysis and curve fitting methods. This suggestion is applicable to the prediction of short-wave frequency field strength, reliability and compatibility during the ionospheric calm period, that is, the monthly median value of parameters such as the critical frequency of the F2 layer and the 3000km propagation factor can be predicted. It can be seen that the ITU-R P.533 recommendation is only applicable to the prediction of HF link parameters during the ionospheric calm period. However, the ionosphere is affected by various mechanisms such as chemistry, dynamics, and electrodynamics, and exhibits complex changing characteristics. When an ionospheric storm occurs, due to the significant deviation of the ionospheric parameters from their background values, the corresponding MUF of the short-wave link will be caused. MUF calculation error distribution and cumulative error distribution of shortwave links during ionospheric storms are shown in Figure 1.

It can be seen that in the prior art, there is still a lack of regular understanding of the change characteristics and predictability of ionospheric parameters during ionospheric storms, as well as the resulting changes in shortwave link parameters.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for calculating the highest available frequency of short-wave links during ionospheric storms.

The present invention adopts following technical scheme:

A method for calculating the highest available frequency of a shortwave link during an ionospheric storm, the improvement of which includes the following steps:

Step 1. Select 5 high-quality oblique measurement links nationwide as background links;

Step 2. Use the vertical survey data fof2, foE and M(3000)F2 factors of 14 domestic radio wave observation stations, and obtain the vertical survey data fof2, foE and M( 3000) F2 factor, above-mentioned fof2 refers to ionospheric F ₂ layer critical frequency, foE refers to ionospheric E layer critical frequency;

Step 3. Obtain the 3 vertical survey data and the highest available frequency MUF data of the oblique survey link at the midpoint of the 5 background links during the historical ionospheric storm, and preprocess the background link data as the following step 4 training samples;

Step 4. Use the interpolated interpolation data obtained in the above step 3 during the ionospheric storm period as the input of the calculation formula for the highest available short-wave frequency recommended by ITU-RP533, and use the oblique measurement data as the output, and use the particle swarm optimization algorithm to optimize the formula For the 20 constant parameters in , set the number of optimizations or optimization errors to obtain the optimal constant parameters;

Step 5. Replace the obtained 20 optimal constant parameters with the constant parameters in the original formula, and use the interpolation of the vertical survey data of 14 domestic radio wave observation stations to obtain the vertical survey data of the specified link midpoint as input, and establish a method suitable for Calculation of the highest usable frequency for HF links during ionospheric storms.

Further, the step 3 specifically includes the following steps:

Step 31, using the fof2 relative deviation df as the criterion for judging the ionospheric storm, wherein, In the formula, fof2 is the observed value, and fof2 _med is the monthly median value. When df is not less than 0.3, it is considered as a positive-phase ionospheric storm, and when df is not greater than -0.2, it is a negative-phase ionospheric storm;

Step 32. Use the vertical survey data of 14 domestic radio wave observation stations and the Kringer interpolation algorithm to obtain 3 vertical survey data at the midpoint of a certain link, and screen a certain period of time according to the above criteria for ionospheric storms During the internal ionospheric storm, the fof2, foE and M(3000)F2 factors of the link midpoint are three vertical measurement data and the highest available frequency data of the oblique measurement link;

Step 33. If the difference between the MUFs of the two links where the transceiver points are switched at the same time does not exceed 3 MHz, then the quality of the data in this group is considered to be reliable and can be used as sample data.

Further, the step 4 specifically includes the following steps:

Step 41. Set and extract the 20 constant parameters in the calculation formula for the highest available frequency of the shortwave link recommended by ITU-R P.533. For the one-hop MUF of the shortwave link whose great circle distance is less than 4000km, the link provided by ITU-R P.533 The road parameter prediction method is as follows:

in:

f _H : electron magnetic spin frequency at the control point;

C _d =X ₁ -X ₂ ZX ₃ Z ² -X ₄ Z ³ +X ₅ Z ⁴ +X ₆ Z ⁵ +X ₇ Z ⁶ ;

in,

Z=1-2d/ _dmax ;

d _max =X ₈ +(X ₉ +X ₁₀ /x ² -X ₁₁ /x ⁴ +X ₁₂ /x ⁶ )(1/BX ₁₃ );

in:

d: propagation path length;

C ₃₀₀₀ : C _d value at 3000km;

x=foF ₂ /foE or X ₂₀ , whichever is larger;

Among them, X ₁ to X ₂₀ are the constant parameters obtained through the particle swarm optimization algorithm in advance;

Step 42. Use the particle swarm algorithm to obtain the optimal 20 constant parameters, use the interpolation obtained in step 2 to obtain the interpolation data training samples of the link midpoint vertical and oblique measurements during the ionospheric storm, and use the ion swarm algorithm to calculate the 20 constant parameters. Optimization, set the number of optimizations or error threshold, and finally obtain 20 optimal constant parameters as follows:

The beneficial effects of the present invention are:

The method for calculating the highest available frequency applicable to short-wave links during ionospheric storms disclosed by the present invention uses this method to realize the acquisition of the highest available frequencies of short-wave links during ionospheric storms. Based on the ITU-R P.533 recommendation for short-wave links The calculation formula of the highest available frequency, combined with the ionospheric state information during the ionospheric storm, takes the interpolation of the ionospheric vertical survey data as the input, and uses the particle swarm optimization algorithm to optimize the maximum available frequency recommended by ITU-R P.533 The 20 constant parameters in the frequency calculation formula are used to obtain the optimal constant parameters, and a method for calculating the highest available frequency suitable for short-wave links during ionospheric storms is established.

Description of drawings

Figure 1 shows the MUF calculation error distribution and cumulative error distribution of shortwave links during ionospheric storms;

Fig. 2 is a schematic flow chart of the calculation method disclosed in Embodiment 1 of the present invention;

Fig. 3 is a comparison between the calculated results of the shortwave link MUF and the measured results during the normal phase ionospheric storm from February 20 to 21, 2017 using the calculation method disclosed in Embodiment 1 of the present invention;

Fig. 4 is a comparison of the calculation results of the shortwave link MUF during the negative phase ionospheric storm on March 22, 2017 and the actual measurement results using the calculation method disclosed in Example 1 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Embodiment 1, as shown in Figure 2, this embodiment discloses a method for calculating the highest available frequency of a shortwave link during an ionospheric storm, including the following steps:

Step 1. Select 5 high-quality oblique measurement links nationwide as background links;

Step 2. Use the vertical survey data fof2, foE and M(3000)F2 factors of 14 domestic radio wave observation stations, and obtain the vertical survey data fof2, foE and M( 3000) F2 factor, above-mentioned fof2 refers to ionospheric F ₂ layer critical frequency, foE refers to ionospheric E layer critical frequency;

Step 3. Obtain the 3 vertical survey data and the highest available frequency MUF data of the oblique survey link at the midpoint of the 5 background links during the historical ionospheric storm, and preprocess the background link data as the following step 4 training samples;

Described step 3 specifically comprises the following steps:

Step 31, using the fof2 relative deviation df as the criterion for judging the ionospheric storm, wherein, In the formula, fof2 is the observed value, and fof2 _med is the monthly median value. When df is not less than 0.3, it is considered as a positive-phase ionospheric storm, and when df is not greater than -0.2, it is a negative-phase ionospheric storm;

Step 32. Use the vertical survey data of 14 domestic radio wave observation stations and the Kringer interpolation algorithm to obtain 3 vertical survey data at the midpoint of a certain link, and screen a certain period of time according to the above criteria for ionospheric storms During the internal ionospheric storm, the fof2, foE and M(3000)F2 factors of the link midpoint are three vertical measurement data and the highest available frequency data of the oblique measurement link;

Step 33. If the difference between the MUFs of the two links where the transceiver points are switched at the same time does not exceed 3 MHz, then the quality of the data in this group is considered to be reliable and can be used as sample data.

Step 4. Use the interpolated interpolation data obtained in the above step 3 during the ionospheric storm period as the input of the calculation formula for the highest available short-wave frequency recommended by ITU-RP533, and use the oblique measurement data as the output, and use the particle swarm optimization algorithm to optimize the formula For the 20 constant parameters in , set the number of optimizations or optimization errors to obtain the optimal constant parameters;

The step 4 specifically includes the following steps:

Step 41. Set and extract the 20 constant parameters in the calculation formula for the highest available frequency of the shortwave link recommended by ITU-R P.533. For the one-hop MUF of the shortwave link whose great circle distance is less than 4000km, the link provided by ITU-R P.533 The road parameter prediction method is as follows:

in:

f _H : electron magnetic spin frequency at the control point;

C _d =X ₁ -X ₂ ZX ₃ Z ² -X ₄ Z ³ +X ₅ Z ⁴ +X ₆ Z ⁵ +X ₇ Z ⁶ ;

in,

Z=1-2d/ _dmax ;

d _max =X ₈ +(X ₉ +X ₁₀ /x ² -X ₁₁ /x ⁴ +X ₁₂ /x ⁶ )(1/BX ₁₃ );

in:

d: propagation path length;

C ₃₀₀₀ : C _d value at 3000km;

x=foF ₂ /foE or X ₂₀ , whichever is larger;

Among them, X ₁ to X ₂₀ are the constant parameters obtained through the particle swarm optimization algorithm in advance;

Step 42. Use the particle swarm algorithm to obtain the optimal 20 constant parameters, use the interpolation obtained in step 2 to obtain the interpolation data training samples of the link midpoint vertical and oblique measurements during the ionospheric storm, and use the ion swarm algorithm to calculate the 20 constant parameters. Optimization, set the number of optimizations or error threshold, and finally obtain 20 optimal constant parameters as follows:

Step 5. Replace the obtained 20 optimal constant parameters with the constant parameters in the original formula, and use the interpolation of the vertical survey data of 14 domestic radio wave observation stations to obtain the vertical survey data of the specified link midpoint as input, and establish a method suitable for Calculation of the highest usable frequency for HF links during ionospheric storms.

In order to verify the reliability of the calculation method during ionospheric storms, the positive-phase ionospheric storm and the negative-phase ionospheric storm on March 22, 2017 at the midpoint of the Guangzhou-Haikou link were selected for verification , as shown in Figure 3 and Figure 4. Table 1 and Table 2 respectively give the comparison of the measured MUF of the Guangzhou-Haikou link and the calculated MUF obtained by this calculation method during the two ionospheric storms. It can be seen from the table that the maximum error is 0.25MHz and the average absolute error is 0.1514MHz during the normal phase ionospheric storm. During negative phase ionospheric storms, the maximum error is 0.25MHz, and the average absolute error is 0.078MHz. It can be seen that it is basically consistent with the measured results, and can accurately reflect the MUF status of the short-wave link.

Table 1 Period of normal phase ionospheric storm from February 20 to 21, 2017

Calculated value and measured value of MUF(MHz) of Guangzhou-Haikou link

Calculated 15.08 14.13 13.54 12.31 11.11 7.95 5.23 measured value 14.99 14.05 13.29 12.09 10.91 7.81 5.15

Table 2 During the negative phase ionospheric storm on March 22, 2017

Calculated value and measured value of MUF(MHz) of Guangzhou-Haikou link

Calculated 12.84 11.97 11.25 11.93 12.14 8.76 6.61 5.88 measured value 12.89 12.01 11.28 12.00 12.31 8.82 6.57 5.84

In summary, the method for calculating the highest available frequency of shortwave links during ionospheric storms disclosed in this embodiment can provide shortwave system users with information on the highest available frequencies during ionospheric storms, and provide effective ionospheric environmental impact information for related system operations support. With the support of the ionospheric vertical and oblique measurements of the radio wave observation station network, it is only necessary to know the information of the designated link receiving and sending points, and then substitute the optimal constant parameters obtained by optimizing the observation data into the highest available shortwave frequency recommended by ITU-R P.533 In the calculation formula, a reliable evaluation of the highest available frequency of the short-wave link during an ionospheric storm can be made, which is of great significance to the performance of the short-wave system during an ionospheric storm.

Claims (3)

1. A method for calculating a highest available frequency for a short wave link during an ionospheric burst, comprising the steps of:

step 1, preferably selecting 5 high-quality oblique links as background links in the national range;

step 2, utilizing the vertical measurement data fof2, foE and M (3000) F2 factors of 14 radio observation stations in China to obtain vertical measurement data fof2, foE and M (3000) F2 factors of the midpoint positions of 5 background links through a Kersge interpolation algorithm, wherein fof2 is an electric separation layer F₂Layer critical frequency, foE refers to the ionized layer E layer critical frequencyRate;

step 3, respectively acquiring 3 vertical measurement data of the middle points of 5 background links in the historical ionosphere storm period and MUF data of the highest available frequency of an oblique measurement link, and preprocessing the background link data to be used as a training sample in the following step 4;

step 4, taking the vertical measurement data of the link midpoint in the ionosphere storm period obtained by interpolation in the step 3 as the input in the ITU-R P533 recommendation short wave highest available frequency calculation formula, taking the oblique measurement data as the output, optimizing 20 constant parameters in the formula by utilizing a particle swarm optimization algorithm, and setting the optimization times or the optimization errors of the parameters to obtain the optimal constant parameters;

and 5, replacing the constant parameters in the original formula with the obtained 20 optimal constant parameters, and establishing a highest available frequency calculation method suitable for the short wave link in the ionospheric storm period by using vertical measurement data of 14 domestic radio wave observation stations to obtain vertical measurement data of a designated link midpoint as input.

2. The method of claim 1, wherein the step 3 comprises the following steps:

step 31, using fof2 relative deviation df as the criterion for ionospheric storm determination, wherein,wherein fof2 is an observed value, fof2_medThe value is the middle of the month, when df is not less than 0.3, the ionospheric storm is considered as positive phase ionospheric storm, and when df is not more than-0.2, the ionospheric storm is considered as negative phase ionospheric storm;

step 32, obtaining 3 vertical measurement data of a midpoint of a certain link by using vertical measurement data of 14 domestic radio wave observation stations and a Kersoge interpolation algorithm, and respectively screening fof2, foE and M (3000) F2 factor 3 vertical measurement data of the midpoint of the link during the ionospheric storm in a certain time period and the highest available frequency data of the oblique measurement link according to the judgment standard of the ionospheric storm;

and step 33, regarding that the difference value of the MUFs of the two links with the same time point interchanging does not exceed 3MHz, namely the group of data is considered to be reliable in quality and can be used as sample data.

3. The method of claim 1, wherein the step 4 comprises the following steps:

step 41, setting and extracting 20 constant parameters in a calculation formula of the highest available frequency of the ITU-R P.533 recommendation short-wave link, and for a short-wave link one-hop MUF with a great circle distance less than 4000km, a link parameter prediction method provided by the ITU-R P.533 recommendation is as follows:

<mrow> <msub> <mi>n</mi> <mn>0</mn> </msub> <msub> <mi>F</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mi>D</mi> <mo>)</mo> </mrow> <mi>M</mi> <mi>U</mi> <mi>F</mi> <mo>=</mo> <mo>&amp;lsqb;</mo> <mn>1</mn> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <msub> <mi>C</mi> <mi>d</mi> </msub> <msub> <mi>C</mi> <mn>3000</mn> </msub> </mfrac> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <mi>B</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>&amp;CenterDot;</mo> <mi>f</mi> <mi>o</mi> <mi>F</mi> <mn>2</mn> <mo>+</mo> <mfrac> <msub> <mi>f</mi> <mi>H</mi> </msub> <mn>2</mn> </mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mfrac> <mi>d</mi> <msub> <mi>d</mi> <mrow> <mi>m</mi> <mi>a</mi> <mi>x</mi> </mrow> </msub> </mfrac> <mo>)</mo> </mrow> </mrow>

wherein:

f_H: the electron magnetic spin frequency at the control point;

C_d＝X₁-X₂·Z-X₃·Z²-X₄·Z³+X₅·Z⁴+X₆·Z⁵+X₇·Z⁶；

wherein,

Z＝1-2d/d_max；

d_max＝X₈+(X₉+X₁₀/x²-X₁₁/x⁴+X₁₂/x⁶)(1/B-X₁₃)；

<mrow> <mi>B</mi> <mo>=</mo> <mi>M</mi> <mrow> <mo>(</mo> <mn>3000</mn> <mo>)</mo> </mrow> <msub> <mi>F</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>X</mi> <mn>14</mn> </msub> <mo>+</mo> <mo>&amp;lsqb;</mo> <msup> <mrow> <mo>&amp;lsqb;</mo> <mi>M</mi> <mrow> <mo>(</mo> <mn>3000</mn> <mo>)</mo> </mrow> <msub> <mi>F</mi> <mn>2</mn> </msub> <mo>&amp;rsqb;</mo> </mrow> <mn>2</mn> </msup> <mo>-</mo> <msub> <mi>X</mi> <mn>15</mn> </msub> <mo>&amp;rsqb;</mo> <mo>&amp;CenterDot;</mo> <mo>&amp;lsqb;</mo> <msub> <mi>X</mi> <mn>16</mn> </msub> <mo>+</mo> <msub> <mi>X</mi> <mn>17</mn> </msub> <mo>&amp;CenterDot;</mo> <mi>s</mi> <mi>i</mi> <mi>n</mi> <mrow> <mo>(</mo> <mfrac> <msub> <mi>X</mi> <mn>19</mn> </msub> <mi>x</mi> </mfrac> <mo>-</mo> <msub> <mi>X</mi> <mn>19</mn> </msub> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

wherein:

d: a propagation path length;

C₃₀₀₀: at 3000kmC_dA value;

x＝foF₂/foE or X₂₀Taking the larger one;

wherein, X₁To X₂₀The constant parameters are obtained in advance through a particle swarm algorithm;

step 42, obtaining the optimal 20 constant parameters by using a particle swarm algorithm, training samples by using data of vertical measurement and oblique measurement of the midpoint of the link during the ionospheric storm period obtained by interpolation in step 2, optimizing the 20 constant parameters by using the ion swarm algorithm, and setting the optimization times or the error threshold value to finally obtain the 20 optimal constant parameters as follows: