CN111800182B - A Design Method for Realizing Flexible Coverage of Global Communication Constellation - Google Patents

Abstract

The invention provides a design method for realizing a flexible coverage global communication constellation, which has a simple structural algorithm and can quickly calculate the number of satellite rings on a satellite constellation and the number of satellites on the satellite ring in an air-ground integrated constellation architecture according to the long radius and the short radius equivalent to an ellipsoid earth, the satellite height and the minimum observation angle; meanwhile, the design method can also design the communication satellite constellation according to the required proportion of the overlapping coverage area of the coverage area, thereby realizing the global flexible coverage of the communication satellite constellation, ensuring the real-time performance and the transmission efficiency of communication, and meeting the requirements of high time sensitivity, multi-task cooperation and other diversity information services.

Description

Design method for realizing flexible coverage of global communication constellation

Technical Field

The invention belongs to the technical field of air-space-ground integrated information network architecture, and particularly relates to a design method for flexibly covering a global communication constellation.

Background

The existing communication constellation design method is generally to use a plurality of satellites to be uniformly distributed on the same orbit to form a satellite ring, and then use a plurality of satellite rings to form a satellite network, i.e. the final required constellation.

When k is large enough, coverage areas of adjacent satellites Si and Si +1 will overlap, as shown in FIG. 1.

The angular distance l between adjacent subsatellite points is as follows: l is 360 °/k.

When the coverage angle d of the satellite>l/2, then the coverage areas of adjacent satellites overlap. The width of the overlapping portion is d_rThen, then

Only when d>180 °/k is significant. With d_rAt least one satellite within the ring can be seen at any time for any point within the wide satellite coverage zone.

In FIG. 2, the crossing point N is the great arc of the vertical satellite orbit, on which P is_LThe point is 90 deg. from the point of intersection. The boundary of the left blind area is P_LIs a center, 90-d_rSmall radius, left blind zone declination range delta_Lmin～δ_LmaxThe following can be obtained:

from the symmetry, the declination range δ of the right blind zone can be obtained from fig. 2_Rmin～δ_RmaxSatisfy the following requirements

If there are P satellite rings, at least P-1 satellites in the net can be seen at any one time at any one location. In order to prevent the blind areas from overlapping, the following design method is adopted.

Requirement that dimension directions do not overlap:

90°-d_r≤i≤d_r

if the satellite is composed of P rings equally spaced, the ring elevation points are 360/P apart. The longitude range occupied by the left (or right) blind area of each ring does not exceed 360 DEG/P, and the blind areas are not overlapped. The condition that the blind areas in the longitudinal direction do not overlap is therefore:

the prior art can only obtain a constellation design method according to the condition that the blind areas are not overlapped. Under the condition that the blind areas are not overlapped, the minimum overlapping coverage proportion of the satellite cannot be obtained.

Disclosure of Invention

In view of this, the present invention provides a design method for flexibly covering a global communication constellation, which simplifies the calculation method and can implement global flexible coverage of a communication satellite constellation.

A design method for realizing flexible coverage of global communication constellations comprises the following steps:

the method comprises the following steps of firstly, calculating the coverage area of each satellite in a constellation, specifically:

if the instantaneous height of the satellite at a certain moment is h, the minimum observation angle of the satellite is recorded as theta, the corresponding coverage angle is recorded as beta, and the radius of the earth is recorded as r, the following results are obtained according to the sine law:

simplifying to obtain:

the radius r' of the bottom surface of the spherical cap of the coverage area is as follows:

r′＝rsinβ

the covered area is:

S＝2πr²(1-cosβ)

secondly, calculating the number of satellites forming a constellation by global seamless coverage, specifically:

the square equivalent coverage angle is η, i.e.:

then, the number of satellites/required for each satellite ring is:

assuming that the earth has a major radius a and a minor radius b, and the constellation adopts polar orbits, the number m of satellites in each satellite ring is:

the number n of satellite rings constituting a satellite constellation is:

step three, calculating the number of satellites of the global flexible coverage constellation, specifically:

assuming that the satellite coverage area overlap on each satellite ring is u%, then the number of satellites m' on each satellite ring is:

assuming that the coverage area overlap of each satellite ring on the constellation is w%, the number n' of satellite rings constituting the satellite constellation is:

the invention has the following beneficial effects:

the invention provides a design method for realizing a flexible coverage global communication constellation, which has simple structural algorithm and can quickly calculate the number of satellite rings on a satellite constellation and the number of satellites on the satellite ring in an air-ground integrated constellation framework according to the long radius and the short radius of an equivalent ellipsoid earth, the satellite height and the minimum observation angle; meanwhile, the design method can also design the communication satellite constellation according to the required proportion of the overlapping coverage area of the coverage area, thereby realizing the global flexible coverage of the communication satellite constellation, ensuring the real-time performance and the transmission efficiency of communication, and meeting the requirements of high time sensitivity, multi-task cooperation and other diversity information services.

Drawings

FIG. 1 is a satellite ring cover band diagram;

FIG. 2 is a range diagram of a satellite ring shadow zone;

FIG. 3 is a schematic diagram of satellite coverage area calculation;

FIG. 4 is a schematic diagram of an equivalent square of a satellite footprint;

fig. 5 is a schematic diagram of an equivalent coverage angle of satellite coverage.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

The first step is to calculate the coverage area of each satellite in the constellation.

As shown in FIG. 3, let the instantaneous altitude of a satellite S at a certain time be h, and the corresponding intersatellite point be G, P₁And P₂Are points on the geometric ground plane. Coverage bandwidth of satellite S is P₁-G-P₂The arc distance of (d) covers an angle δ. The satellite has a center angle gamma to the ground.

In a remote area in the maximum coverage area, the satellite communication effect is poor due to the influence of ground shelters, so that a minimum observation angle theta exists, the corresponding coverage angle is recorded as beta, the central angle of the satellite to the ground is alpha, and the radius of the earth is r.

From the sine law it is known that:

simplifying to obtain:

the radius r' of the bottom surface of the spherical cap of the coverage area is as follows:

r′＝rsinβ

the covered area is:

S＝2πr²(1-cosβ)

and secondly, calculating the number of satellites forming the constellation by the global seamless coverage.

If the area of the spherical crown of the satellite coverage area is directly used for calculating the number of satellite rings and satellites, the calculation difficulty is greatly increased due to the satellite overlapping coverage and the satellite blind area. The computing process is optimized by adopting a computing method of an equivalent square. Since the design of the satellite is facilitated and the difficulty of the orbit control is reduced, the design of a circular orbit constellation is adopted.

As shown in fig. 4, due to Q₁Q₂The distance between the two sides is 2 r', the equivalent square side length is obtained

Namely, it is

As shown in FIG. 5, the equivalent coverage angle of the square is η, i.e.

Then, the number of satellites required for each satellite ring (the number of satellite rings required for the constellation), l, is:

the earth is an ellipsoid, the long radius is a, the short radius is b, the height of the satellite is h, and the polar orbit is selected as the constellation. Then, the number m of satellites on each satellite ring is:

the number n of satellite rings constituting a satellite constellation is:

and thirdly, calculating the number of satellites of the global flexible coverage constellation.

The proposed constellation of global flexible coverage can require the overlapping area of the coverage area according to the actual situation.

The satellite coverage area overlap on each satellite ring is u%, then the number m' of satellites on each satellite ring is:

the coverage area overlap of each satellite ring on the constellation is w%, then the number n' of satellite rings constituting the satellite constellation is:

in summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (1)

1. A design method for realizing flexible coverage of global communication constellations is characterized by comprising the following steps:

the method comprises the following steps of firstly, calculating the coverage area of each satellite in a constellation, specifically:

if the instantaneous height of the satellite at a certain moment is h, the minimum observation angle of the satellite is recorded as theta, the corresponding coverage angle is recorded as beta, and the radius of the earth is recorded as r, the following results are obtained according to the sine law:

simplifying to obtain:

the radius r' of the bottom surface of the spherical cap of the coverage area is as follows:

r′＝rsinβ

the covered area is:

S＝2πr²(1-cosβ)

secondly, calculating the number of satellites forming a constellation by global seamless coverage, specifically:

the square equivalent coverage angle is η, i.e.:

then, the number of satellites/required for each satellite ring is:

assuming that the earth has a major radius a and a minor radius b, and the constellation adopts polar orbits, the number m of satellites in each satellite ring is:

the number n of satellite rings constituting a satellite constellation is:

step three, calculating the number of satellites of the global flexible coverage constellation, specifically:

assuming that the satellite coverage area overlap on each satellite ring is u%, then the number of satellites m' on each satellite ring is:

assuming that the coverage area overlap of each satellite ring on the constellation is w%, the number n' of satellite rings constituting the satellite constellation is:

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