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CN-122015762-A - Method for calculating ground clearance height of lowest scattering point of troposphere

CN122015762ACN 122015762 ACN122015762 ACN 122015762ACN-122015762-A

Abstract

The invention provides a method for calculating the ground clearance of a lowest scattering point of a troposphere, which constructs a geometric relationship based on a scattering path of the troposphere through a transmitting antenna, a receiving electric wave ray and a ground coordinate of the highest obstacle encountered by the transmitting electric wave ray, and provides a calculation flow and a method for the ground clearance of the lowest scattering point of the troposphere. The invention well reflects the shape of the earth, can accurately measure the distance between the earth surfaces, and is more in line with the signal transmission loss requirement of a troposphere scattering system compared with the method provided by the ITU-R.P.617 recommendation, and can improve the calculation accuracy of parameters such as a scattering body dependence coefficient, a loss probability conversion factor and the like in the troposphere scattering loss prediction.

Inventors

  • ZHANG JIANMING
  • LI LIN

Assignees

  • 中国电子科技集团公司第二十研究所

Dates

Publication Date
20260512
Application Date
20251217

Claims (6)

  1. 1. The method for calculating the ground clearance of the lowest scattering point of the troposphere is characterized by comprising the following steps: Step 1, constructing a troposphere scattering path geometric relationship; Wherein: a transmitting antenna geodetic coordinate; the earth coordinates of the receiving antenna; the earth coordinates of the highest obstacle encountered for the emission of the radio wave rays; The earth coordinates of the highest obstacle encountered for receiving the radio wave rays; Is the lowest scattering point; is the lowest scattering point And the center of the sphere of the earth An intersection of the line with the earth's surface; the distance between the highest obstacle and the transmitting antenna is met for transmitting the radio wave rays; the highest obstacle is encountered for receiving the radio wave rays and the distance between the receiving antenna is the same; Is the minimum scattering angle; The included angle between the connecting line of the transmitting antenna and the receiving antenna and the transmitting visual line is set; the included angle between the connecting line of the transmitting antenna and the receiving visual line is set; Step 2, calculating the transmitting antenna And receiving antenna Straight line distance between ; Step 3, calculating the distance between the highest obstacle encountered by the emitted radio wave rays and the emitting antenna ; Step4, calculating the included angle between the connection line of the transmitting antenna and the receiving antenna and the transmitting visual flat line : (7) Wherein: Is the earth radius; the distance between the highest obstacle and the transmitting antenna is met for transmitting the radio wave rays; Step 5, calculating the distance between the highest obstacle encountered by the received radio wave rays and the receiving antenna ; Step 6, calculating the included angle between the connection line of the transmitting antenna and the receiving visual line ; (10) Wherein: Is the earth radius; the highest obstacle is encountered for receiving the radio wave rays and the distance between the receiving antenna is the same; Step 7, calculating the distance between the transmitting antenna and the sphere center of the earth ; (11) Step 8, calculating the distance between the receiving antenna and the sphere center of the earth ; (12) Step 9, calculating the connection line between the transmitting antenna and the receiving antenna Connecting with transmitting antenna-sphere center Included angle of (2) : (13) Step 10, calculating the connection line of the transmitting antenna and the receiving antenna Connecting with receiving antenna-sphere center Included angle of (2) : (14) Step 11, calculating the length of the large circular arcs of the transmitting antenna and the receiving antenna : (15) Step 12, calculating the ground clearance of the lowest scattering point of the troposphere ; The length of the (2) is the ground clearance height of the lowest scattering point of the troposphere; Setting: ; ; ; ; ; ; Let variable (16); The lowest scattering point of the troposphere is at a height from ground of: (17); Is the ground level of the lowest scattering point of the flow layer.
  2. 2. The method for calculating the minimum scattering point ground clearance of the troposphere according to claim 1, wherein: said step 2 calculates the transmitting antenna And receiving antenna Straight line distance between The specific steps of (a) are as follows: Step 2.1, converting the position of a transmitting antenna and a receiving antenna into a WGS-84 geocentric earth fixed rectangular coordinate; The ground-centered and fixed rectangular coordinates of the transmitting antenna WGS-84 are as follows: (2) Wherein: for the transmit antenna longitude to be, For the transmit antenna latitude, In order to transmit the altitude of the antenna, For the first degree of eccentricity the disc drive, , Is a long half shaft of the earth ellipsoid, ; The ground-centered and fixed rectangular coordinates of the receiving antenna WGS-84 are as follows: (3) Wherein: longitude for the receiving antenna; latitude for receiving antenna; Altitude for the receiving antenna; for the first degree of eccentricity the disc drive, ; A long radius that is an earth reference ellipsoid; ; Step 2.2, calculating the linear distance between the transmitting antenna and the receiving antenna: (4)。
  3. 3. The method for calculating the minimum scattering point ground clearance of the troposphere according to claim 1, wherein: The specific step of calculating the distance between the highest obstacle encountered by the emission electric wave ray and the emission antenna in the step 3 is as follows: The position of the highest obstacle encountered by the emitted radio wave rays is converted into the WGS-84 geocentric and geocentric rectangular coordinates: (5) Wherein: encountering the highest obstacle longitude for transmitting the radio wave rays; the highest obstacle latitude is encountered for transmitting the radio wave rays; the highest obstacle altitude is encountered for the emission of radio waves; Calculating the distance between the highest obstacle encountered by the emitted radio wave rays and the emitting antenna: (6)。
  4. 4. the method for calculating the minimum scattering point ground clearance of the troposphere according to claim 1, wherein: step 5 of calculating the distance between the receiving antenna and the highest obstacle encountered by the received radio wave rays The specific steps of (a) are as follows: The received radio wave rays meet the highest obstacle and are converted into WGS-84 geocentric earth rectangular coordinates (8) Wherein: encountering the highest obstacle longitude for receiving the radio wave rays; The highest obstacle latitude is encountered for receiving the radio wave rays; the highest obstacle altitude is encountered for receiving the radio wave rays; Calculating the distance between the highest obstacle encountered by the received radio wave rays and the receiving antenna (9)。
  5. 5. An electronic device, comprising: one or more processors; a 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 configured to perform the method of any of claims 1-4.
  6. 6. A computer readable storage medium storing program code which is callable by a processor to perform the method according to any one of claims 1-4.

Description

Method for calculating ground clearance height of lowest scattering point of troposphere Technical Field The invention relates to the field of troposphere calculation, in particular to a height calculation method. Background According to the troposphere scattering transmission loss prediction method provided by Zhang Minggao institutions, the international telecommunication union in 1992 releases the propagation prediction technology and data required by the design of beyond visual range radio relay system, the formulas such as a climate zone map, probability loss fitting and the like are improved, the formulas are upgraded to the ITU-R.P.617-2, 2013, the average median transmission loss distribution prediction of the worst month with the time percentage exceeding 50% is revised, the formulas are upgraded to the ITU-R.P.617-3, 2017, the average loss median calculation formula of the troposphere scattering transmission year is further revised, the weather factor calculation formulas, the global average sea level refractive index and refractive index gradient distribution map are increased, the formulas of minimum scattering point elevation are given in the years of "(Propagation Prediction Techniques and Data Required for the Design of Trans-Horizon Radio-Relay Systems);2012, and the formulas are upgraded to the ITU-R.P.617-5. The minimum scattering point ground clearance of the troposphere is an important parameter for calculating the dependence coefficient of the troposphere scattering body and the median value of the annual average loss of the troposphere scattering transmission. ITU-R.P.617-1, ITU-R.P.617-2, ITU-R.P.617-3, ITU-R.P.617-4 recommendations, the given tropospheric minimum scattering point elevation calculation formula is as follows: (km) (1) Wherein: Is the scattering angle (mrad); Is an equivalent earth radius factor; Is the earth radius. After the ITU-R.P.617-5 recommendation modifies the ITU-R.P.617-1/2/3/4 equation, the given tropospheric minimum scattering point elevation calculation equation is as follows: (2) Wherein: 、 the altitude of the receiving antenna and the transmitting antenna are respectively; the path length of the receiving and transmitting antenna; is a scattering angle; 、 the elevation angles of the viewing lines of the transmitting antenna and the receiving antenna respectively. The formula for calculating the minimum scattering point elevation of the troposphere is based on the following assumptions, ITU-R.P.617-1, ITU-R.P.617-2, ITU-R.P.617-3, and ITU-R.P.617-4 recommendations. 1) Altitude of transmitting antennaAltitude of receiving antenna; 2) The emitted electric wave rays meet the highest obstacle altitudeThe received radio wave rays meet the highest obstacle altitude; 3) The linear distance between the transmitting antenna and the receiving antenna is equal to the length of the large arc; 4) With equivalent length of earth radius ) The earth is approximated as a standard sphere. The ITU-r.p.617-5 recommendation, although revised in computing methods, is still based on equivalent spherical radii. Due to various assumption conditions, deviation is caused to the calculation of the minimum scattering point of the troposphere. In order to accurately predict the tropospheric loss, a method for calculating the minimum scattering point ground clearance of the tropospheric is provided based on a transmitting antenna, a receiving antenna and the ground coordinates of the highest obstacle. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a method for calculating the ground clearance of the lowest scattering point of a troposphere. The technical scheme adopted for solving the technical problems is as follows: the invention adopts the following method and steps to calculate the ground clearance of the lowest scattering point of the troposphere. Step 1, constructing a troposphere scattering path geometric relationship; the tropospheric scatter path geometry is shown in figure 1. Wherein: a transmitting antenna geodetic coordinate; the earth coordinates of the receiving antenna; the earth coordinates of the highest obstacle encountered for the emission of the radio wave rays; The earth coordinates of the highest obstacle encountered for receiving the radio wave rays; Is the lowest scattering point; is the lowest scattering point And the center of the sphere of the earthAn intersection of the line with the earth's surface; the distance between the highest obstacle and the transmitting antenna is met for transmitting the radio wave rays; the highest obstacle is encountered for receiving the radio wave rays and the distance between the receiving antenna is the same; Is the minimum scattering angle; The included angle between the connecting line of the transmitting antenna and the receiving antenna and the transmitting visual line is set; the included angle between the connecting line of the transmitting antenna and the rece