阅读说明：本技术 一种下行链路最差干扰快速估算方法 (Method for quickly estimating worst interference of downlink ) 是由 赵书阁 贺泉 向开恒 高利春 周洪刚 李小玉 康静 于 2021-05-21 设计创作，主要内容包括：本发明公开了一种下行链路最差干扰快速估算方法,包括：S101：初始化NGSO卫星的纬度幅角；S102：计算NGSO卫星在J2000坐标系的三维位置矢量、赤经和J2000坐标系到轨道坐标系的坐标转换矩阵；S103：初始化GSO卫星的赤经；S104：计算GSO卫星在J2000坐标系的位置矢量；S105：计算GSO卫星到NGSO卫星的延长线在轨道坐标系的单位矢量；S106：判断GSO卫星到NGSO卫星的延长线是否与地球相交；S107：计算与地球交点在J2000坐标系的矢量表达式；S108：计算NGSO卫星空间电台的发射在GSO卫星到NGSO卫星的延长线方向的发射增益；S109：计算与地球交点处GSO地球站的EPFD；S110：存储EPFD、对应NGSO卫星纬度幅角、GSO卫星赤经和地球表面交点的坐标；S111：更新GSO的赤经；S112：更新NGSO的纬度幅角。(The invention discloses a method for quickly estimating worst interference of a downlink, which comprises the following steps: s101: initializing a latitude argument of the NGSO satellite; s102: calculating a three-dimensional position vector of the NGSO satellite in a J2000 coordinate system, the right ascension and a coordinate conversion matrix from the J2000 coordinate system to an orbit coordinate system; s103: initializing the right ascension of the GSO satellite; s104: calculating a position vector of the GSO satellite in a J2000 coordinate system; s105: calculating a unit vector of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system; s106: judging whether an extension line from the GSO satellite to the NGSO satellite intersects with the earth or not; s107: calculating a vector expression of the intersection point of the earth and the earth in a J2000 coordinate system; s108: calculating the emission gain of the emission of the NGSO satellite space radio station in the extension line direction from the GSO satellite to the NGSO satellite; s109: calculating the EPFD of the GSO earth station at the intersection point of the earth and the earth; s110: storing the coordinates of the EPFD, the latitude argument of the corresponding NGSO satellite, the declination of the GSO satellite and the intersection point of the earth surface; s111: renewal of the erythro channels of GSO; s112: and updating the latitude argument of the NGSO.)

1. A method for fast estimating the worst interference of a downlink, comprising the steps of:

s101: initializing a latitude argument of the NGSO satellite;

s102: calculating a three-dimensional position vector of the NGSO satellite in a J2000 coordinate system, the right ascension and a coordinate conversion matrix from the J2000 coordinate system to an orbit coordinate system;

s103: initializing the right ascension of the GSO satellite;

s104: calculating a position vector of the GSO satellite in a J2000 coordinate system;

s105: calculating a unit vector of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system;

s106: judging whether the extension line from the GSO satellite to the NGSO satellite intersects with the earth surface, if so, turning to S107, and turning to S111;

s107: calculating a vector expression of an intersection point of an extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system;

s108: calculating the emission gain of the emission of the NGSO satellite space radio station in the extension line direction from the GSO satellite to the NGSO satellite;

s109: calculating the EPFD of the GSO earth station transmitted by the NGSO satellite space radio station at the intersection of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s110: storing the EPFD and coordinates corresponding to the latitude argument of the NGSO satellite, the ascension of the GSO satellite and the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s111: updating the right ascension of the GSO satellite, and switching to S104 after judgment until all right ascension calculations are completed;

s112: and updating the latitude argument of the NGSO satellite, and turning to S102 after judgment until the calculation of all the latitude arguments is completed.

2. The method of claim 1, wherein initializing the latitudinal argument of the NGSO satellite comprises:

s1011: taking the latitude argument of the NGSO satellite as u ═ u₀Wherein u is₀As initial latitude argument u of NGSO satellite₀＝0°。

3. The method of claim 2, wherein the calculating of the position vector of the NGSO satellite in the J2000 coordinate system, the right ascension and the coordinate transformation matrix from the J2000 coordinate system to the orbital coordinate system comprises:

s1021: calculating a true anomaly angle according to the latitude argument u and the anomaly argument omega:

θ＝u-ω

s1022: and calculating the radius of the NGSO satellite orbit according to the true near point angle as follows:

wherein, a is the semi-major axis of the NGSO satellite, and e is the eccentricity of the NGSO satellite;

s1023: the position vector of the NGSO satellite in the J2000 coordinate system is:

wherein the content of the first and second substances,as a unit vector, the calculation formula is:

wherein, omega is the right ascension of the NGSO satellite, and i is the inclination of the NGSO satellite orbit;

s1024: the three-dimensional component of the position vector of the NGSO satellite in the J2000 coordinate system is recorded as x_N、y_NAnd z_NThe right ascension of the NGSO satellite in the J2000 coordinate system is:

s1025: the coordinate transformation matrix from the J2000 coordinate system to the orbit coordinate system is:

wherein M is_x()、M_y() And M_z() The coordinate transformation matrix around the X, Y and Z axes, respectively, is calculated as:

4. the method of claim 3, wherein initializing the right ascension of the GSO satellite comprises:

s1031: initializing the red channels of the GSO satellite:

L_G＝L_N-ΔL_G

wherein, Δ L_GIs half of the width of the red channel interval of the GSO satellite.

5. The method of claim 4, wherein calculating the position vector of the GSO satellite in the J2000 coordinate system comprises:

s1041: GSO satellite in J2000 coordinate systemPosition vector r of_GComprises the following steps:

wherein R is_eIs the mean radius of the earth, B_GDeclination of GSO satellite H_GHeight of GSO satellites.

6. The method of claim 5, wherein calculating the unit vector of the orbital coordinate system of the extension lines of the GSO satellite to the NGSO satellite comprises:

s1051: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the J2000 coordinate system is as follows:

s1052: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the orbital coordinate system is as follows:

7. the method of claim 6, wherein determining whether the extension from the GSO satellite to the NGSO satellite intersects the surface of the earth comprises:

s1061: the included angle between the tangent line from the NGSO satellite to the earth and the direction of the + Z axis of the orbital coordinate system is as follows:

s1062: the included angle between the extension line from the GSO satellite to the NGSO satellite and the direction of the + Z axis of the orbital coordinate system is as follows:

wherein zo is a third-dimensional component of a unit vector do of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system;

s1063: when in useWhen the earth surface is in contact with the extension line, the extension line intersects with the earth surface; otherwise, the extension does not intersect the surface of the earth.

8. The method of claim 7, wherein said calculating a vector representation of an intersection point of an extension of a GSO satellite to a NGSO satellite and the earth's surface in a J2000 coordinate system comprises:

s1071: the vector expression of the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system is as follows:

r_d＝r_N+kd_i

wherein, the coefficient k is calculated by the formula:

9. the method of claim 8, wherein said calculating the EPFD of the GSO earth station at the intersection of the GSO satellite to NGSO satellite extension and the earth's surface of the launch of the NGSO satellite space radio comprises:

s1091: the EPFD of the GSO earth station at the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface is transmitted by the NGSO satellite space radio station as follows:

EPFD＝P_t+G_t-10log₁₀(4πd²)+G_r-G_rmax

wherein, P_tIs the transmit power, G, of an NGSO satellite space radio station_tFor launching of NGSO satellite space stations in the direction of extension from GSO satellite to NGSO satellite, G_rIs the reception gain, G, of the GSO earth station_rmaxIs the maximum receiving gain of the GSO earth station, and G is the maximum receiving gain of the GSO earth station when the GSO earth station is in the extension line direction of the GSO satellite and the NGSO satellite_r＝G_rmaxD is the distance between the NGSO satellite space station and the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface, namely d ═ r_d-r_N|。

10. The method of claim 9, wherein updating the right ascension of the GSO satellite, after determining, going to S104 until all right ascension calculations are completed comprises:

s1111: updating the red channels of the GSO satellite:

first calculate L_G1：

L_G1＝L_G+L_s

Updating L_G：

L_G＝L_G1

Wherein L is_sThe update step length of the GSO satellite right ascension;

s1112: judgment of L_G≤L_N+ΔL_GIf so, go to S104, otherwise go to S112.

11. The method of claim 10, wherein updating the latitudinal argument of the NGSO satellite, after determining, transitions to S102 until all latitudinal arguments are calculated comprises:

s1121: updating the latitude argument of the NGSO satellite:

first calculate u₁：

u₁＝u+u_s

Updating u:

u＝u₁

wherein u is_sUpdating step length of latitude argument of NGSO satellite;

s1122: and judging u is less than or equal to 360 degrees, if so, turning to S102, and otherwise, ending.

Technical Field

The present invention relates to the field of fast estimation of the worst interference of the downlink. And more particularly, to a method for quickly estimating worst interference of a downlink.

Background

Internet access anytime and anywhere is the most important feature of the current information age, and in recent years, many domestic and foreign enterprises propose a non-geostationary satellite orbit (NGSO) satellite system and plan to provide internet access service anywhere and anytime for the world. The main frequencies used by the NGSO satellite system include Ku band, Ka band, etc., according to radio regulations, the Equivalent Power Flux Density (EPFD) generated at any point on the earth's surface visible to the Geostationary Satellite Orbit (GSO) according to the transmissions of the space station of the NGSO satellite system must not exceed a given limit for a given percentage of time, and the earth station reference antenna and reference bandwidth corresponding to the EPFD limit are given.

For the reference frequency band of 17.8-18.6GHz, the reference antenna diameter of the earth station reference antenna is 1m, the reference radiation pattern is ITU-R s.1428-1 recommendation, the reference bandwidth is 40kHz, and the limits that the EPFD transmitted by the NGSO satellite system should not exceed are shown in table 1, it can be seen that the second column of table 1 gives several "limit points", the third column gives the corresponding percentage of time that cannot be exceeded for each "limit point", and a schematic diagram of the relationship between the percentage of time that the EPFD transmitted by a certain NGSO satellite system exceeds the corresponding value and the limit points of table 1 is shown in fig. 1. The EPFD limit of the last row of the second column is "-164", corresponding to a percentage of time not exceeded of "100%", i.e. the limit "-164" cannot be exceeded at all. The format of the limits that the EPFD transmitted by the NGSO satellite system must not exceed for other different frequency bands, earth station reference antenna diameters or reference radiation patterns is similar to the format of the limits of table 1, i.e. there is a limit that cannot be exceeded at all.

Because the EPFD limit is given in the form of time percentage, the limit checking and calculating are usually completed by adopting a time slicing method, namely, a certain total simulation duration and a certain simulation step length are set, EPFD at different simulation moments is respectively calculated, and the time percentage of the EPFD exceeding the corresponding value is counted. In order to obtain a simulation result with high reliability, the total simulation time length should be as long as possible, and the simulation step length should be as short as possible, which brings about the problem that the simulation calculation time consumption is long, and whether the interference between systems meets the requirements cannot be quickly determined, thereby affecting the design progress of the system scheme.

Disclosure of Invention

One objective of the present invention is to provide a method for quickly estimating the worst downlink interference, which is used to quickly determine the worst downlink interference of an NGSO satellite system to a GSO satellite system, so as to quickly determine whether the downlink interference of the NGSO satellite system to the GSO satellite system meets the requirement of a limit.

In order to achieve the purpose, the invention adopts the following technical scheme:

a downlink worst interference fast estimation method comprises the following steps:

s101: initializing a latitude argument of the NGSO satellite;

s102: calculating a three-dimensional position vector of the NGSO satellite in a J2000 coordinate system, the right ascension and a coordinate conversion matrix from the J2000 coordinate system to an orbit coordinate system;

s103: initializing the right ascension of the GSO satellite;

s104: calculating a position vector of the GSO satellite in a J2000 coordinate system;

s105: calculating a unit vector of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system;

s106: judging whether the extension line from the GSO satellite to the NGSO satellite intersects with the earth surface, if so, turning to S107, and turning to S111;

s107: calculating a vector expression of an intersection point of an extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system;

s108: calculating the emission gain of the emission of the NGSO satellite space radio station in the extension line direction from the GSO satellite to the NGSO satellite;

s109: calculating the EPFD of the GSO earth station transmitted by the NGSO satellite space radio station at the intersection of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s110: storing the EPFD and coordinates corresponding to the latitude argument of the NGSO satellite, the ascension of the GSO satellite and the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s111: updating the right ascension of the GSO satellite, and switching to S104 after judgment until all right ascension calculations are completed;

s112: and updating the latitude argument of the NGSO satellite, and turning to S102 after judgment until the calculation of all the latitude arguments is completed.

In one specific example, the initializing the latitudinal argument of the NGSO satellite includes:

s1011: taking the latitude argument of the NGSO satellite as u ═ u₀Wherein u is₀As initial latitude argument u of NGSO satellite₀＝0°。

In one specific example, the calculating of the position vector of the NGSO satellite in the J2000 coordinate system, the right ascension, and the coordinate transformation matrix of the J2000 coordinate system to the orbit coordinate system includes:

s1021: calculating a true anomaly angle according to the latitude argument u and the anomaly argument omega:

θ＝u-ω

s1022: and calculating the radius of the NGSO satellite orbit according to the true near point angle as follows:

wherein, a is the semi-major axis of the NGSO satellite, and e is the eccentricity of the NGSO satellite;

s1023: the position vector of the NGSO satellite in the J2000 coordinate system is:

wherein the content of the first and second substances,as a unit vector, the calculation formula is:

wherein, omega is the right ascension of the NGSO satellite, and i is the inclination of the NGSO satellite orbit;

s1024: the three-dimensional component of the position vector of the NGSO satellite in the J2000 coordinate system is recorded as x_N、y_NAnd z_NThe right ascension of the NGSO satellite in the J2000 coordinate system is:

s1025: the coordinate transformation matrix from the J2000 coordinate system to the orbit coordinate system is:

wherein M is_x()、M_y() And M_z() The coordinate transformation matrix around the X, Y and Z axes, respectively, is calculated as:

in one specific example, the initializing the right ascension of the GSO satellite includes:

s1031: initializing the red channels of the GSO satellite:

L_G＝L_N-ΔL_G

wherein, Δ L_GIs half of the width of the red channel interval of the GSO satellite.

In one specific example, the calculating the position vector of the GSO satellite in the J2000 coordinate system includes:

s1041: position vector r of GSO satellite in J2000 coordinate system_GComprises the following steps:

wherein R is_eIs the mean radius of the earth, B_GDeclination of GSO satellite H_GHeight of GSO satellites.

In one specific example, the calculating the unit vector of the extension line of the GSO satellite to the NGSO satellite in the orbital coordinate system comprises:

s1051: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the J2000 coordinate system is as follows:

s1052: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the orbital coordinate system is as follows:

in one specific example, the determining whether the extension line from the GSO satellite to the NGSO satellite intersects the surface of the earth comprises:

s1061: the included angle between the tangent line from the NGSO satellite to the earth and the direction of the + Z axis of the orbital coordinate system is as follows:

s1062: the included angle between the extension line from the GSO satellite to the NGSO satellite and the direction of the + Z axis of the orbital coordinate system is as follows:

wherein zo is a third-dimensional component of a unit vector do of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system;

s1063: when in useWhen the earth surface is in contact with the extension line, the extension line intersects with the earth surface; otherwise, the extension does not intersect the surface of the earth.

In one specific example, the calculating the vector expression of the intersection point of the extension line of the GSO satellite to the NGSO satellite and the earth surface in the J2000 coordinate system comprises:

s1071: the vector expression of the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system is as follows:

r_d＝r_N+kd_i

wherein, the coefficient k is calculated by the formula:

in one specific example, said calculating the EPFD of the GSO earth station at the intersection of the GSO satellite to NGSO satellite extension and the earth's surface of the launch of the NGSO satellite space station comprises:

s1091: the EPFD of the GSO earth station at the intersection point of the extension line from the GSO satellite to the NGSO satellite and the ground is transmitted by the NGSO satellite space radio station as follows:

EPFD＝P_t+G_t-10log₁₀(4πd²)+G_r-G_rmax

wherein, P_tIs the transmit power, G, of an NGSO satellite space radio station_tExtension line method from GSO satellite to NGSO satellite for transmitting NGSO satellite space radio stationGain of transmission, G_rIs the reception gain, G, of the GSO earth station_rmaxIs the maximum receiving gain of the GSO earth station, and G is the maximum receiving gain of the GSO earth station when the GSO earth station is in the extension line direction of the GSO satellite and the NGSO satellite_r＝G_rmaxD is the distance between the NGSO satellite space station and the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface, namely d ═ r_d-r_N|。

In a specific example, the method for updating the right ascension of the GSO satellite, and after judging, the method goes to S104 until all right ascension calculations are completed includes:

s1111: updating the red channels of the GSO satellite:

first calculate L_G1：

L_G1＝L_G+L_s

Updating L_G：

L_G＝L_G1

Wherein L is_sThe update step length of the GSO satellite right ascension;

s1112: judgment of L_G≤L_N+ΔL_GIf so, go to S104, otherwise go to S112.

In a specific example, the updating of the latitudinal argument of the NGSO satellite is judged and then goes to S102 until the calculation of all latitudinal arguments is completed includes:

s1121: updating the latitude argument of the NGSO satellite:

first calculate u₁：

u₁＝u+u_s

Updating u:

u＝u₁

wherein u is_sUpdating step length of latitude argument of NGSO satellite;

s1122: and judging u is less than or equal to 360 degrees, if so, turning to S102, and otherwise, ending.

The invention has the following beneficial effects:

the method for quickly estimating the worst downlink interference can be used for quickly determining the worst downlink interference of an NGSO satellite system to a GSO satellite system, so that whether the downlink interference of the NGSO satellite system to the GSO satellite system meets the requirement of a limit value can be quickly judged.

The positions of the satellite and the earth station of the worst scene obtained by the method for quickly estimating the worst interference of the downlink can be used as the initial value of time slice simulation analysis, so that a basis can be provided for selecting the initial simulation value of the time slice simulation analysis.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of the percentage of time that an EPFD transmitted by an NGSO satellite system exceeds a corresponding value versus a limit point;

FIG. 2 is a schematic diagram of a spatial geometry relationship of a GSO satellite, an NGSO satellite and an earth station corresponding to a worst interference scenario;

FIG. 3 is a flowchart of a method for fast estimating the worst interference of a downlink according to an embodiment of the present invention;

FIG. 4 is a diagram showing the variation of EPFD with latitude argument without interference avoidance measures in the worst scenario (i.e., when the NGSO satellite is on the connection line between the GSO satellite and the GSO earth station);

fig. 5 shows the change of the EPFD with the latitude argument in the worst scenario (i.e., the NGSO satellite is on the line connecting the GSO satellite and the GSO earth station) when the interference avoidance measure is taken.

Detailed Description

In order to make the technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The motion trail of the NGSO satellite can be defined by six free variables, namely a semimajor axis a, an eccentricity e, an orbit inclination angle i, a rising intersection declination omega, a near place argument omega and a latitude argument u, wherein the first five variables are invariables or slow variables, and the last variable latitude argument is a fast variable, so that the change of the position of the NGSO satellite mainly depends on the latitude argument; meanwhile, the position of the GSO satellite can be described in terms of fixed point longitude.

Based on the method, when the worst interference is searched, the latitude argument of the NGSO satellite and the longitude of the GSO satellite are used as variables to respectively determine the position of the NGSO satellite and the position of the GSO satellite, and according to worst scene analysis, the GSO earth station is positioned at the intersection point of the extension lines of the GSO satellite and the NGSO satellite and the earth surface, so that the position of the GSO earth station is determined. After the position of the GSO earth station is determined, the distance between the NGSO satellite and the GSO earth station and the transmitting gain of the transmitting antenna of the NGSO satellite in the direction from the NGSO satellite to the GSO earth station can be determined, and the EPFD generated by the NGSO satellite at the NGSO earth station on the earth surface can be calculated. Meanwhile, the NGSO satellite position, the GSO satellite position and the GSO earth station position obtained by the worst interference fast estimation method can be used as initial values of further time slice simulation analysis, so that basis can be provided for initial value selection of the time slice simulation analysis.

The invention discloses a method for quickly estimating worst interference of a downlink, which relates to a method for quickly estimating the worst interference of a non-geostationary satellite orbit satellite system (NGSO) to a global system for mobile communications (GSO) satellite system, and the method firstly analyzes and determines the worst interference scene according to the characteristics of a calculation formula of an EPFD; and then establishing an EPFD calculation method when the latitude argument of the NGSO and the longitude of the GSO satellite take different values in the worst interference scene, and further determining the maximum value of the EPFD.

According to the EPFD limit format, there is a limit for each scene that "100%" cannot exceed, i.e., a value that cannot be exceeded at all. As shown in fig. 1 and table 1, when the maximum value of the EPFD transmitted by the NGSO satellite system exceeds the limit value corresponding to the time percentage of "100%", the EPFD transmitted by the NGSO satellite system does not meet the requirement, so that it is not necessary to further determine whether other limit values are met, and a quick preliminary determination can be implemented, so that a quick calculation of worst interference of a downlink has an important meaning.

TABLE 1

According to the calculation formula of the EPFD, the EPFD is mainly determined by the transmission power, the transmission antenna gain, the reception antenna gain, and the propagation distance. The transmission power is a design parameter of the satellite system, and is usually a fixed value or a small variation range, and the change amount of the EPFD caused by the propagation distance and the change of the gain of the transmitting antenna caused by the transmission off-angle are small relative to the change of the receiving gain caused by the receiving off-angle, as shown in fig. 2, so that the worst interference of the downlink usually occurs when the NGSO satellite is located on the connection line between the GSO satellite and the GSO earth station.

One embodiment of the present invention provides a method for quickly estimating the worst interference of a downlink, as shown in fig. 3, including the following steps:

s101: initializing a latitude argument of the NGSO satellite;

s102: calculating a three-dimensional position vector of the NGSO satellite in a J2000 coordinate system, the right ascension and a coordinate conversion matrix from the J2000 coordinate system to an orbit coordinate system;

s103: initializing the right ascension of the GSO satellite;

s104: calculating a position vector of the GSO satellite in a J2000 coordinate system;

s105: calculating a unit vector of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system;

s106: judging whether the extension line from the GSO satellite to the NGSO satellite intersects with the earth surface, if so, turning to S107, and turning to S111;

s107: calculating a vector expression of an intersection point of an extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system;

s108: calculating the emission gain of the emission of the NGSO satellite space radio station in the extension line direction from the GSO satellite to the NGSO satellite;

s109: calculating the EPFD of the GSO earth station transmitted by the NGSO satellite space radio station at the intersection of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s110: storing the EPFD and coordinates corresponding to the latitude argument of the NGSO satellite, the ascension of the GSO satellite and the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface;

s111: updating the right ascension of the GSO satellite, and switching to S104 after judgment until all right ascension calculations are completed;

s112: and updating the latitude argument of the NGSO satellite, and turning to S102 after judgment until the calculation of all the latitude arguments is completed.

In one specific example, the initializing the latitudinal argument of the NGSO satellite includes:

s1011: taking the latitude argument of the NGSO satellite as u ═ u₀Wherein u is₀As initial latitude argument u of NGSO satellite₀＝0°。

In one specific example, the calculating of the position vector of the NGSO satellite in the J2000 coordinate system, the right ascension, and the coordinate transformation matrix of the J2000 coordinate system to the orbit coordinate system includes:

s1021: calculating a true anomaly angle according to the latitude argument u and the anomaly argument omega:

θ＝u-ω

s1022: and calculating the radius of the NGSO satellite orbit according to the true near point angle as follows:

wherein, a is the semi-major axis of the NGSO satellite, and e is the eccentricity of the NGSO satellite;

s1023: the position vector of the NGSO satellite in the J2000 coordinate system is:

wherein the content of the first and second substances,as a unit vector, the calculation formula is:

wherein, omega is the right ascension of the NGSO satellite, and i is the inclination of the NGSO satellite orbit;

s1024: the three-dimensional component of the position vector of the NGSO satellite in the J2000 coordinate system is recorded as x_N、y_NAnd z_NThe right ascension of the NGSO satellite in the J2000 coordinate system is:

s1025: the coordinate transformation matrix from the J2000 coordinate system to the orbit coordinate system is:

wherein M is_x()、M_y() And M_z() The coordinate transformation matrix around the X, Y and Z axes, respectively, is calculated as:

in one specific example, the initializing the right ascension of the GSO satellite includes:

s1031: initializing the red channels of the GSO satellite:

L_G＝L_N-ΔL_G

wherein, Δ L_GIs half of the width of the red channel interval of the GSO satellite.

In one specific example, the calculating the position vector of the GSO satellite in the J2000 coordinate system includes:

s1041: position vector r of GSO satellite in J2000 coordinate system_GComprises the following steps:

wherein R is_eIs the mean radius of the earth, B_GDeclination of GSO satellite H_GHeight of GSO satellites.

In one specific example, the calculating the unit vector of the extension line of the GSO satellite to the NGSO satellite in the orbital coordinate system comprises:

s1051: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the J2000 coordinate system is as follows:

s1052: the unit vector of the extension line from the GSO satellite to the NGSO satellite in the orbital coordinate system is as follows:

in one specific example, the determining whether the extension line from the GSO satellite to the NGSO satellite intersects the earth includes:

s1061: the included angle between the tangent line from the NGSO satellite to the earth and the direction of the + Z axis of the orbital coordinate system is as follows:

s1062: the included angle between the extension line from the GSO satellite to the NGSO satellite and the direction of the + Z axis of the orbital coordinate system is as follows:

wherein zo is a third-dimensional component of a unit vector do of an extension line from the GSO satellite to the NGSO satellite in an orbital coordinate system, namely a component on a Z axis;

s1063: when in useWhen the earth surface is in contact with the extension line, the extension line intersects with the earth surface; otherwise, the extension does not intersect the surface of the earth.

In one specific example, the calculating the vector expression of the intersection point of the extension line of the GSO satellite to the NGSO satellite and the earth surface in the J2000 coordinate system comprises:

s1071: the vector expression of the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface in a J2000 coordinate system is as follows:

r_d＝r_N+kd_i

wherein, the coefficient k is calculated by the formula:

in a specific embodiment, said calculating the transmission gain of the NGSO satellite space radio station in the extension direction from the GSO satellite to the NGSO satellite comprises:

s1081: the antenna directional diagram function of the transmitting antenna of the NGSO satellite space radio station can be generally given in an orbital coordinate system, and the transmitting gain G of the transmitting antenna of the NGSO satellite space radio station in the extension line direction from the GSO satellite to the NGSO satellite can be determined according to the unit vector do of the extension line from the GSO satellite to the NGSO satellite given by S1052 in the orbital coordinate system_t。

In one specific example, said calculating the EPFD of the GSO earth station at the intersection of the GSO satellite to NGSO satellite extension and the earth's surface of the launch of the NGSO satellite space station comprises:

s1091: the EPFD of the GSO earth station at the intersection point of the extension line from the GSO satellite to the NGSO satellite and the earth surface is transmitted by the NGSO satellite space radio station as follows:

EPFD＝P_t+G_t-10log₁₀(4πd²)+G_r-G_rmax

wherein, P_tIs the transmit power of the NGSO satellite space radio, usually a given fixed value, G_tFor launching of NGSO satellite space stations in the direction of extension from GSO satellite to NGSO satellite, G_rIs the reception gain, G, of the GSO earth station_rmaxThe maximum reception gain of the GSO earth station is determined by the characteristics of the antenna, and G is determined when the GSO earth station is in the extension line direction of the GSO satellite and the NGSO satellite_r＝G_rmaxD is the intersection point distance between the extension line from the NGSO satellite space station to the NGSO satellite from the GSO satellite and the earth surface, namely d ═ r_d-r_N|。

In a specific example, the step of switching to S104 after the determination of the right ascension of the updated GSO satellite until all right ascension calculations are completed includes:

s1111: updating the red channels of the GSO satellite:

first calculate L_G1：

L_G1＝L_G+L_s

Updating L_G：

L_G＝L_G1

Wherein L is_sThe update step length of the GSO satellite right ascension;

s1112: judgment of L_G≤L_N+ΔL_GIf so, go to S104, otherwise go to S112.

In a specific example, the updating of the latitudinal argument of the NGSO satellite is judged and then goes to S102 until the calculation of all latitudinal arguments is completed includes:

s1121: updating the latitude argument of the NGSO satellite:

first calculate u₁：

u₁＝u+u_s

Updating u:

u＝u₁

wherein u is_sUpdating step length of latitude argument of NGSO satellite;

s1122: and judging u is less than or equal to 360 degrees, if so, turning to S102, and otherwise, ending.

The updating step length of the GSO satellite right ascension and the updating step length of the NGSO satellite latitude argument are custom values in simulation, and are taken to be about 1 second for example.

The invention provides a specific embodiment that the height of the orbit of the NGSO satellite system is 1200km, the inclination angle of the orbit is 87 degrees, and the eccentricity of the orbit is 0; the opening angle of the NGSO satellite beam in the X-axis direction of the orbital coordinate system is +/-24 degrees.

And under the condition of not taking interference avoidance measures, calculating the EPFD transmitted by a certain NGSO satellite system when the NGSO satellite is at different latitude argument and the GSO satellite is at different longitude by adopting the steps. The difference between the longitude of the GSO satellite and the longitude of the NGSO satellite is 0 °, the EPFD transmitted by the NGSO satellite varies with the amplitude of latitude, and the variation of the maximum EPFD transmitted by the NGSO satellite with the amplitude of latitude when the longitude of the GSO satellite takes different values is shown in fig. 4, which shows that: the maximum EPFD emitted by a single NGSO satellite is-137.5 dB (W/m2)/40kHz and exceeds-164 dB (W/m2)/40kHz, and the EPFD emitted by the NGSO satellite system can be determined to exceed the EPFD limit value without further simulation by adopting a time slicing method.

And under the condition of adopting interference avoidance measures, calculating EPFD transmitted by a certain NGSO satellite system when the NGSO satellite is at different latitude argument and the GSO satellite is at different longitude by adopting the steps. The difference between the longitude of the GSO satellite and the longitude of the NGSO satellite is 0 °, the EPFD transmitted by the NGSO satellite varies with the amplitude of latitude, and the variation of the maximum EPFD transmitted by the NGSO satellite with the amplitude of latitude when the longitude of the GSO satellite takes different values is shown in fig. 5, which shows that: the maximum EPFD emitted by a single NGSO satellite is-165.84 dB (W/m2)/40kHz, and does not exceed-164 dB (W/m2)/40kHz, so that the EPFD emitted by the NGSO satellite system meets the EPFD limit value under the condition of preliminarily judging the interference avoidance measures, and the effectiveness of the interference avoidance measures can be quickly judged.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.