Method for calculating height from lowest troposphere scattering point to transmitting and receiving antenna connecting line

Abstract

The invention provides a method for calculating the connecting line height from the lowest scattering point of a troposphere to a receiving and transmitting antenna. The connecting line height from the lowest scattering point of the troposphere to the receiving and transmitting antenna is calculated. The spherical distance between the transmitting antenna and the receiving antenna is calculated; the prime unitary circle curvature radius of the earth reference ellipsoid at the transmitting antenna latitude and the receiving antenna latitude is calculated; the linear distance between the transmitting end and the receiving end is calculated; and the connecting line height from the lowest troposphere scattering point to the receiving antenna and the transmitting antenna is calculated. On the basis of the distance between the transmitting antenna and the receiving antenna and the included angle between the receiving antenna and the transmitting antenna, a mathematical model of the height between the lowest troposphere scattering point and the connecting line between the receiving antenna and the transmitting antenna is provided, compared with a method of an ITU-R.P.617 proposal, the troposphere scattering transmission requirement is better met, and in troposphere scattering loss prediction, the troposphere scattering loss prediction accuracy is improved. And the calculation accuracy of parameters such as a scatterer dependency coefficient, elevation angle offset loss and antenna low-frame loss can be improved.

Description

Technical Field

[0001] This invention relates to the field of tropospheric scattering transmission of radio waves, and in particular to a method for calculating the height of the tropospheric scattering point. This invention solves the problem of accurately calculating the height of the lowest scattering point to the line connecting the transmitting and receiving antennas in tropospheric radio wave transmission. Compared with the method in the International Telecommunication Union (ITU) Recommendation ITU-RP617, it can effectively improve the calculation accuracy. By calculating the propagation loss dependence coefficient on the scatterer, the median annual average loss of tropospheric scattering transmission, the elevation offset loss, and the antenna undermount loss, it can achieve accurate prediction of tropospheric scattering transmission loss. Background Technology

[0002] Based on the method for predicting tropospheric scattering transmission loss proposed by Academician Zhang Minggao, the International Telecommunication Union (ITU) published ITU-RP 617-1, "Propagation Prediction Techniques and Data Required for the Design of Trans-Horizon Radio-Relay Systems," in 1992. After several revisions, it was upgraded to ITU-RP 617-2, ITU-RP 617-3, ITU-RP 617-4, and ITU-RP 617-5 in 2012, 2013, 2017, and 2019, respectively.

[0003] The height of the line connecting the lowest tropospheric scattering point to the transmitting and receiving antennas is an important parameter for predicting tropospheric scattering loss. The calculation formulas given in ITU-RP617-1, ITU-RP617-2, and ITU-RP617-3 recommendations are as follows:

[0004] (km) (1)

[0005] in: The scattering angle is (mrad).

[0006] The path length (km) is for the transmit and receive antennas.

[0007] The formulas for calculating the height of the line connecting the lowest tropospheric scattering point to the transmitting and receiving antennas in ITU-RP617-1, ITU-RP617-2, and ITU-RP617-3 recommendations are derived based on several assumptions.

[0008] (1) Assume the altitude of the transmitting antenna Altitude of receiving antenna ;

[0009] (2) Assume the altitude of the highest obstacle to the transmitting antenna. The highest altitude of the receiving antenna obstacle ;

[0010] (3) Assume that the straight-line distance between the transmitting and receiving antennas is equal to the length of their great circle arc;

[0011] (4) Ignore the influence of the latitude of the transmitting and receiving antennas.

[0012] Due to various assumptions, the accuracy of the calculation results can be affected, and the deviation will be greater when the transmitting and receiving antennas are at higher altitudes. To accurately predict tropospheric transmission loss, a method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas is proposed based on the Earth's reference ellipsoid. Summary of the Invention

[0013] To overcome the shortcomings of the prior art, the present invention provides a method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas, and calculates the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas.

[0014] The specific steps of the technical solution adopted by this invention to solve its technical problem are as follows:

[0015] Step 1. Construct the geometric relationship of the tropospheric scattering path;

[0016] Step 2. Calculate the spherical distance between the transmitting antenna and the receiving antenna;

[0017] Step 3. Calculate the radii of curvature of the Earth's reference ellipsoid at the latitudes of the transmitting and receiving antennas;

[0018] Step 4. Calculate the straight-line distance between the transmitter and receiver. ;

[0019] Step 5. Calculate the height of the line connecting the lowest scattering point in the troposphere to the receiving antenna and the transmitting antenna.

[0020] In the tropospheric scattering path geometry in step 1, O represents the Earth's center. The location of the transmitting antenna is B, and the latitude of the transmitting antenna is B. t The longitude of the transmitting antenna is L. t The altitude of the transmitting antenna is h. t ;

[0021] The location of the receiving antenna is B, and the latitude of the receiving antenna is B. r The longitude of the receiving antenna is L. r The altitude of the receiving antenna is h.r ;

[0022] The highest obstacle to the transmitting antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas;

[0023] The highest obstacle to the receiving antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas;

[0024] This is the lowest scattering point in the troposphere; The lowest scattering point The foot of the perpendicular from the line connecting the transmitting antenna and the receiving antenna;

[0025] The angle between the line connecting the transmitting and receiving antennas and the line of sight at the transmitting end; The angle between the line connecting the transmitting and receiving antennas and the horizon line of the receiving end; The angle between the transmitting horizon and the receiving horizon is the minimum tropospheric scattering angle.

[0026] In step 2, the spherical distance d between the transmitting antenna and the receiving antenna is calculated according to formula (2):

[0027] (2).

[0028] The latitude of the transmitting antenna The radius of curvature of the angular circle is: ;

[0029] latitude of the receiving antenna The radius of curvature of the angular circle is: ;

[0030] in: For the first eccentricity, ; The major radius of the Earth's ellipsoid. .

[0031] The straight-line distance between the transmitter and receiver in step 4 for:

[0032] (3)

[0033] in: The altitude of the transmitting antenna. Altitude of the receiving antenna; This represents the spherical distance between the transmitting antenna and the receiving antenna.

[0034] In step 5, the height of the line connecting the lowest tropospheric scattering point to the receiving and transmitting antennas is... The calculation formula is as follows:

[0035] (4)

[0036] in: The angle between the line connecting the transmitting and receiving antennas and the transmitting line of sight; The angle between the line connecting the transmitting and receiving antennas and the receiving line of sight; This is the straight-line distance between the transmitting antenna and the receiving antenna.

[0037] An electronic device includes: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs are configured to perform the methods described above.

[0038] A computer-readable storage medium storing program code that can be invoked by a processor to perform the method described above.

[0039] The beneficial effect of this invention is that it provides a method for calculating the height of the line connecting the lowest tropospheric scattering point to the transmitting and receiving antennas. By constructing the geometric relationship of the tropospheric scattering path, and based on the distance between the transmitting and receiving antennas and the angle between the horizon lines, a mathematical model for the height of the line connecting the lowest tropospheric scattering point to the transmitting and receiving antennas is proposed. Compared with the method in ITU-RP617 Recommendation, this method is more in line with the requirements of tropospheric scattering transmission. In the prediction of tropospheric scattering loss, it can improve the calculation accuracy of parameters such as the scatterer dependence coefficient, elevation offset loss, and antenna low-mount loss. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the geometric relationship of the tropospheric scattering path in this invention.

[0041] Figure 2 The angle between the line connecting the transmitting and receiving antennas and the transmitting line of sight. The contour map, in mrad.

[0042] Figure 3 The angle between the line connecting the transmitting and receiving antennas and the receiving line of sight. The contour map, in mrad.

[0043] Figure 4 This is a contour map showing the height H of the line connecting the lowest tropospheric scattering point to the transmitting and receiving antennas, in km.

[0044] Figure 5 The height difference between the ITU-RP617 method and the present invention The contour map, in meters. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Step 1. Construct the geometric relationship of the tropospheric scattering path, as shown in the figure below. Figure 1 As shown.

[0047] O represents the Earth's center. The location of the transmitting antenna is B, and the latitude of the transmitting antenna is B. t The longitude of the transmitting antenna is L. t The altitude of the transmitting antenna is h. t ;

[0048] The location of the receiving antenna is B, and the latitude of the receiving antenna is B. r The longitude of the receiving antenna is L. r The altitude of the receiving antenna is h. r ;

[0049] The highest obstacle to the transmitting antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas;

[0050] The highest obstacle to the receiving antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas;

[0051] This is the lowest scattering point in the troposphere; The lowest scattering point The foot of the perpendicular from the line connecting the transmitting antenna and the receiving antenna;

[0052] The angle between the line connecting the transmitting and receiving antennas and the line of sight at the transmitting end; The angle between the line connecting the transmitting and receiving antennas and the horizon line of the receiving end; The angle between the transmitting horizon and the receiving horizon is the minimum tropospheric scattering angle.

[0053] Step 2. Calculate the spherical distance between the transmitting antenna and the receiving antenna;

[0054] The spherical distance d between the transmitting antenna and the receiving antenna is calculated according to formula (2):

[0055] (2)

[0056] Step 3. Calculate the radii of curvature of the Earth's reference ellipsoid at the latitudes of the transmitting and receiving antennas;

[0057] The latitude of the transmitting antenna The radius of curvature of the angular circle is:

[0058] latitude of the receiving antenna The radius of curvature of the angular circle is:

[0059] in: For the first eccentricity, ; The major radius of the Earth's ellipsoid. ;

[0060] Step 4. Calculate the straight-line distance between the transmitter and receiver. ;

[0061] (3)

[0062] in: The altitude of the transmitting antenna. Altitude of the receiving antenna; This is the spherical distance between the transmitting antenna and the receiving antenna;

[0063] Step 5. Calculate the height of the line connecting the lowest tropospheric scattering point to the receiving and transmitting antennas;

[0064] Depend on Figure 1 It can be seen that, The length is the height of the line connecting the lowest scattering point in the troposphere to the receiving antenna and the transmitting antenna. The calculation formula is as follows:

[0065] (4)

[0066] in: The angle between the line connecting the transmitting and receiving antennas and the transmitting line of sight; The angle between the line connecting the transmitting and receiving antennas and the receiving line of sight; This is the straight-line distance between the transmitting antenna and the receiving antenna.

[0067] The following is an example:

[0068] (1) Location of transmitting antenna:

[0069] longitude ,latitude ;

[0070] (2) Calculation of beyond-line-of-sight distance;

[0071] When the altitude of both the transmitting and receiving antennas is 1km, the over-line-of-sight distance calculated using equation (5) is 260.6km;

[0072] (5)

[0073] (3) Scope of analysis

[0074] The distance between the receiving and transmitting antennas is greater than 260.6 km, in the area between 28° and 40° north latitude and 100° and 118° east longitude.

[0075] (4) Analysis results

[0076] Angle between the line connecting the transmitting and receiving antennas and the transmitting line of sight like Figure 2 The angle between the line connecting the transmitting and receiving antennas and the receiving line of sight. like Figure 3 The present invention is used to measure the height of the line connecting the lowest tropospheric scattering point to the receiving antenna and the transmitting antenna. Analysis results as follows Figure 4 .

[0077] The height of the line connecting the lowest tropospheric scattering point to the receiving and transmitting antennas, calculated according to formula (1) in ITU-RP617 Recommendation, is as follows: , Figure 5 To apply the formulas in ITU-RP617 Recommendation and this invention, the difference in height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas is calculated. .

[0078] Simulation analysis shows that:

[0079] (1) The algorithm proposed in this invention can effectively analyze the height of the line connecting the lowest scattering point in the troposphere to the receiving antenna and the transmitting antenna;

[0080] (2) Applying the formula of ITU-RP617 Recommendation and the present invention to calculate the height of the line connecting the lowest tropospheric scattering point to the receiving antenna and the transmitting antenna, the difference changes from positive deviation to negative deviation as the distance between the transmitting and receiving antennas increases;

[0081] (3) After the location of the transmitting antenna is determined, the latitude of the receiving antenna will affect the calculation results;

[0082] (4) When the altitude of the transmitting antenna and the receiving antenna changes, the calculation results of this invention and the method provided in ITU-RP617 will also be different.

[0083] The main reason for the difference between the two algorithms is that the mathematical model in the ITU-RP617 recommendation is based on a number of assumptions, while the present invention does not have too many assumptions. Based on the mathematical model of the Earth's reference ellipsoid, it can improve the accuracy of the calculation of the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas.

Claims

1. A method for calculating the height of the line connecting the lowest tropospheric scattering point to the transceiver antenna, characterized in that... Includes the following steps: Step 1. Construct the geometric relationship of the tropospheric scattering path; Step 2. Calculate the spherical distance between the transmitting antenna and the receiving antenna; Step 3. Calculate the radii of curvature of the Earth's reference ellipsoid at the latitudes of the transmitting and receiving antennas; Step 4. Calculate the straight-line distance between the transmitter and receiver. ; Step 5. Calculate the height of the line connecting the lowest scattering point in the troposphere to the receiving antenna and the transmitting antenna.

2. The method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas according to claim 1, characterized in that: In the tropospheric scattering path geometry in step 1, O represents the Earth's center. The location of the transmitting antenna is B, and the latitude of the transmitting antenna is B. t The longitude of the transmitting antenna is L. t The altitude of the transmitting antenna is h. t ; The location of the receiving antenna is B, and the latitude of the receiving antenna is B. r The longitude of the receiving antenna is L. r The altitude of the receiving antenna is h. r ; The highest obstacle to the transmitting antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas; The highest obstacle to the receiving antenna on the line connecting the great circle arc of the Earth's surface between the transmitting and receiving antennas; This is the lowest scattering point in the troposphere; The lowest scattering point The foot of the perpendicular from the line connecting the transmitting antenna and the receiving antenna; The angle between the line connecting the transmitting and receiving antennas and the line of sight at the transmitting end; The angle between the line connecting the transmitting and receiving antennas and the horizon line of the receiving end; The angle between the transmitting horizon and the receiving horizon is the minimum tropospheric scattering angle.

3. The method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas according to claim 1, characterized in that: In step 2, the spherical distance d between the transmitting antenna and the receiving antenna is calculated according to formula (2): （2）。 4. The method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas according to claim 1, characterized in that: The latitude of the transmitting antenna The radius of curvature of the angular circle is: ; latitude of the receiving antenna The radius of curvature of the angular circle is: ; in: For the first eccentricity, ; The major radius of the Earth's ellipsoid. .

5. The method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas according to claim 1, characterized in that: The straight-line distance between the transmitter and receiver in step 4 for: （3） in: The altitude of the transmitting antenna. Altitude of the receiving antenna; This represents the spherical distance between the transmitting antenna and the receiving antenna.

6. The method for calculating the height from the lowest tropospheric scattering point to the line connecting the transmitting and receiving antennas according to claim 1, characterized in that: In step 5, the height of the line connecting the lowest tropospheric scattering point to the receiving and transmitting antennas is... The calculation formula is as follows: （4） in: The angle between the line connecting the transmitting and receiving antennas and the transmitting line of sight; The angle between the line connecting the transmitting and receiving antennas and the receiving line of sight; This is the straight-line distance between the transmitting antenna and the receiving antenna.

7. An electronic device, characterized in that, include: One or more processors; Memory; One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs being configured to perform the method as described in any one of claims 1-6.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program code that can be invoked by a processor to execute the method as described in any one of claims 1-6.

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