CN115583369B

CN115583369B - Ubiquitous perception observation method for GEO space debris by low-orbit multi-observation platform

Info

Publication number: CN115583369B
Application number: CN202211237133.1A
Authority: CN
Inventors: 冯飞; 李智; 邢飞; 薛莉; 宋翊宁; 陶雪峰; 赵迪
Original assignee: 63921 Troops of PLA
Current assignee: 63921 Troops of PLA
Priority date: 2022-10-11
Filing date: 2022-10-11
Publication date: 2023-04-07
Anticipated expiration: 2042-10-11
Also published as: CN115583369A

Abstract

The invention discloses a ubiquitous sensing observation method for GEO space debris by a low-orbit multi-observation platform, which comprises the following steps of: in the morning and evening sun synchronous orbit height interval, different numbers of evenly distributed spacecrafts which run on the same orbit height are used as observation platforms, the optical axis directions of star sensors on the observation platforms are set to be consistent, so that a scanning circle which takes any point on 90-i declination as a circle center and is constructed based on the optical axis directions of the star sensors and can cover the boundary of the GEO zone as a radius is formed on the GEO zone; the observation platform in the non-morning and evening sun synchronous track height interval adopts a cross observation mode, and the optical axis direction of the star sensor on the inclined track observation platform is not collinear with the vector of the connecting line from the geocenter to the observation platform; the ubiquitous sensing full coverage and the multiple coverage of the GEO space debris in one day are realized. The technical problem that the star sensor cannot realize short-time multi-azimuth observation on the GEO space debris is solved, and the early warning and collision avoidance capacity of the space debris is remarkably enhanced.

Description

Ubiquitous perception observation method for GEO space debris by low-orbit multi-observation platform

Technical Field

The invention belongs to the technical field of space situation perception, and relates to a ubiquitous perception observation method of a low-orbit multi-observation platform for GEO space debris.

Background

Geosynchronous Orbit (GEO) space debris, GEO space debris for short, does not emit light, and the brightness of the space debris mainly depends on the reflection of sunlight, so that the space debris can be captured by a star sensor of an observation platform, as shown in fig. 1. However, due to the change of the high-speed relative position relationship between the space debris and the observation platform in the space, the light incident angle and the light emergent angle of the space debris also present dynamic changes, the observation efficiency is low because the star sensor is fixedly connected with the spacecraft body and cannot follow up and track, the detection capability of the star sensor of the observation platform is limited, the imaging of the dark and weak space debris cannot be realized, the imaging under the strong sunlight interference condition cannot be realized, and the full-time and omnidirectional observation of the space debris cannot be realized. The observation position needs to be designed.

According to statistics of the nervous scientist alliance, as long as 2019, 6 months and 20 days, 179 active LEO spacecrafts in China are obtained, wherein 132 spacecrafts in the sun synchronous orbit reach 74.3 percent. A large number of sun synchronous orbit spacecrafts provide possibility for realizing space debris ubiquitous perception conception based on star sensors. The sun synchronous orbit has the characteristic that the precession angular velocity is equal to the annual motion of the flat sun, so that the sun synchronous orbit is always kept at a favorable position for observing space debris. Compared with the prior art, due to the characteristic that the star sensor is fixedly installed on the satellite body and cannot rotate, the time period for observing activities of the spacecraft running on other orbits every year is relatively limited along with annual motion of the sun. The space debris itself does not emit light, and forms a point image in the sensor by reflection of sunlight. The ubiquitous perception observation configuration is closely related to the space debris photometric calculation process, and the calculation process is as follows:

the bidirectional reflectance distribution function BRDF is a function describing the relationship between incident light and reflected light on the surface of the material. The method is commonly used for constructing scattering characteristic models of different materials and has higher accuracy than diffuse reflection. The BRDF expression is as follows:

wherein l is the incident direction, v is the exit direction, β _l Is the angle of incidence, beta _v To the angle of emergence, dL _v dE is the differential radiance of the reflected light in the outgoing direction _l Is the differential irradiance in the incident direction.

The spectrum of the sun is equivalent to black body radiation at a temperature of 5900k, and visible sunlight is a parallel light source in deep space. Since the brightness of the spacecraft in the penumbra region is negligible, the following analysis only considers the occlusion of the earth's ghost, not the penumbra. For the sun-synchronous orbit, the spatial relationship of the observation platform, the target and the sun is as shown in fig. 2 when viewed from the north pole of the earth. The angle between the sun, the space debris, and the observation platform is called the phase angle.

The luminance calculation of the space debris is carried out in two steps, firstly, the sun is used as a radiation source, and the irradiance and the reflected radiation exitance of the space debris are calculated; and then, calculating the target irradiance received by the star sensor by taking the target as a radiation source. The BRDF from the irradiance of the sun, the target, can be derived as follows:

the radiant flux density is related to the wavelength of the light, and the radiant flux density M of the sun can be expressed as:

wherein, c ₁ ＝3.741844×10 ⁴ (W·cm ² ·μm ⁴ ) Is a first blackbody radiation constant; c. C ₂ =1.438769 (cm · K) is the second blackbody radiation constant, λ is the wavelength (μm), and T is the thermodynamic temperature (K). Let the mean solar radius be R _sun ＝6.9599×10 ⁵ km, average distance of day and earth R _SE ＝1.4959787×10 ⁸ km, irradiance E when sunlight reaches the outer edge of the earth's atmosphere _sun Can be expressed as:

it can be seen that irradiance is inversely proportional to the square of distance, with greater attenuation of irradiance the further away from the source. Since the GEO radius is much smaller than the distance to the sun, the irradiance may be approximately equal to the irradiance of sunlight when it reaches the space debris. The irradiance E of the sun in the visible band is about 0.38 μm to about 0.76 μm _Vsun Comprises the following steps:

let dA be the unit bin of the space debris surface, the radiation intensity of the target can be expressed as:

I _v ＝dL _v dAcosβ _v ＝E _Vsun f _v (l,v)cosβ _l cosβ _v dA

let R _TO Is the distance of the target from the observation platform, S _o Regarding the optical aperture area of the star sensor, and regarding the target as a radiation source, the total radiation flux entering the star sensor is as follows:

by the definition of irradiance, the irradiance of the obtained space debris received by the star sensor is as follows:

the apparent star of the sun is known as m _sun = 26.74, apparent star of space debris, etc. m _T Relative to the sun, with respect to the logarithm of irradiance of the two, the apparent star, etc., which can further be targeted, has the following expression:

wherein, star is used to describe the brightness of celestial body, and the smaller the star value, the brighter the celestial body. All the stars and the like referred to in the present invention are all visual stars and the like.

Wherein [ formula (I) ] _A f _v (l,v)cosθ _l cosθ _v dA is the Optical Cross-sectional area (OCS) of the space debris, and is only related to the material, shape and size of the space debris, and the emergent and incident angles of the rays, but not to the specific parameters of the sun and the star sensor.

OCS＝∫ _A f _v (l,v)cosθ _l cosθ _v dA

Based on the calculation model, the following simulation is carried out:

looking down from the north pole of the earth, as shown in fig. 3, beta is a phase angle, the target runs from a west-side starting point to an east-side end point for 12h, and the sun and the space debris are respectively positioned on two sides of the track surface of the platform, so that the observation platform is always positioned at a favorable observation position for the target.

As the target moves from west to east, the results of the target star, etc. simulation are shown in FIGS. 4a and 4 b. Fig. 4a shows the variation trend of the star and the like in the field of view of the star sensor when the GEO target moves from west to east on the summer solstice, and fig. 4b shows the corresponding result in the spring minute. Firstly, the relative position relationship of the sun, the space debris and the observation platform in the space is considered during the calculation of the OCS, but the earth body shielding is not considered, the time-varying relationship of the star and the like shown in the figures 4a and 4b is drawn, then the shielding of the earth is considered, the section of the earth shielding the sight line between the observation platform and the target is marked by a dotted line, and the section of the earth shielding the sunlight of the target is marked by a dotted line, namely the target enters the earth ghost area.

It can be seen that when the target is located at a position at a phase angle close to 90 degrees (near the start and end positions), the brightness of the target is extremely low, but as the phase angle decreases, the brightness rises quickly and then fluctuates slowly. If 12 stars etc. are used as detectable star threshold value of the star sensor, the detectable arc segment will cover nearly 80% of the simulation period.

On the basis of the space debris star and the like calculation, the inventor provides a ubiquitous sensing observation method of a low-orbit multi-observation platform for GEO space debris.

The stereo perception method highlights the ubiquitous property, namely the ubiquitous property is ubiquitous, so that the application range is expanded, and the threshold is reduced. The ubiquitous sensing observation configuration is not limited to a certain observation platform orbit, but the spacecrafts with different orbits are included in the available observation platform category. For example, a spacecraft operating in 400km altitude, with a 45 ° inclination near-circular orbit, at J ₂ Under the influence of item perturbation, the precession angular velocity of the orbital plane is-5.15 degrees/day (the minus sign indicates that the motion direction is opposite to the apparent motion direction of the sun), then the relative motion angular velocity of the sun and the orbital plane reaches 6.13 degrees/day, namely within a period of about 59 days, at most two observation windows appear on both sides of a rising intersection point and a falling intersection point respectively according to the calculation of luminosityAs a result, each observation window is about 20 days in duration with 12 stars and the like as a limit, but the actual observable time is further reduced in consideration of the earth's body occlusion, as shown in fig. 1. Nevertheless, the spacecraft with the non-sun synchronous orbit is used as the beneficial supplement of space debris observation, and the full-time and omnidirectional observation of the space debris can be realized.

Disclosure of Invention

On one hand, the low-orbit spacecraft for observing the fragments of the GEO space are mostly a few special observation platforms, the orbit type is single, and the low-orbit spacecraft has short capability in the aspects of coverage timeliness, observation revisit degree and the like. On the other hand, the star sensor is widely installed on various spacecraft platforms, is a necessary attitude determination sensor for the spacecraft, and determines the spatial azimuth inertial direction from the shot star map background, thereby providing an attitude measurement reference for the spacecraft. The star sensor also has the observation capability of capturing a space target. However, because the space debris and the observation platform have a relatively fast relative movement speed, and the star sensor is fixedly connected with the spacecraft body, the space debris cannot be tracked in a following way like other special sensors, so that the observation time and the observation angle of the space debris by the star sensor of the observation platform are limited, and the technology of observing the space debris by the star sensor cannot be popularized. Therefore, the invention provides a ubiquitous sensing observation method for GEO space debris by using a low-orbit multi-observation platform, which is a space-based multi-platform natural intersection observation configuration and comprises a scanning circle formed by a plurality of observation platforms running in a morning-evening sun synchronous orbit and a ubiquitous sensing observation method for GEO space debris by using a low-orbit multi-observation platform supplemented by a non-morning-evening sun synchronous orbit observation platform and an inclined orbit observation platform. A certain number of observation platforms on the scanning circle can ensure rapid full coverage of the GEO band in one day, and star sensors of the non-morning and non-evening sun synchronous orbit observation platforms and the inclined orbit observation platforms can point to the boundary area of the scanning circle from a plurality of positions in the space to form space three-dimensional coverage.

In order to achieve the purpose of full-time and omnidirectional observation of space debris, the invention is specifically realized by the following technical scheme:

a ubiquitous perception observation method of a low-rail multi-observation platform for GEO space debris is disclosed, wherein the low rail comprises a morning and evening sun synchronous rail, a non-morning and evening sun synchronous rail and an inclined rail; the method comprises the following steps:

step one, in the morning and evening sun synchronous orbit height interval, different numbers of evenly distributed spacecrafts which run on the same orbit height are used as observation platforms, and the optical axis directions of star sensors on the observation platforms are set to be consistent, so that a scanning circle which takes any point on 90-i declination as a circle center and is constructed based on the optical axis directions of the star sensors and can cover the boundary of the GEO zone as a radius is formed on the GEO zone; scanning tracks of a plurality of spacecrafts on the GEO belt are overlapped, so that ubiquitous perception observation foundation coverage of GEO space fragments is realized; wherein i is the track inclination angle of the morning and evening sun synchronous track where the observation platform is located;

step two, an observation platform in the non-morning-evening sun synchronous track height interval adopts a cross observation mode, so that a star sensor on the observation platform on the non-morning-evening sun synchronous track points to a scanning circle boundary where the track position of the observation platform is opposite, and a non-morning-evening sun synchronous track star sensor view field and a morning-evening sun synchronous track star sensor view field are in an arc section intersected at the scanning circle boundary to form ubiquitous sensing stereo observation and basic coverage supplement for GEO space debris;

setting the optical axis direction of a star sensor on the inclined track observation platform to be not collinear with the vector of a connecting line from the geocenter to the observation platform; and the other supplement for covering the ubiquitous sensing observation foundation of the GEO space debris is formed in an arc section where the field of view of the inclined track star sensor and the field of view of the non-morning-evening sun synchronous track star sensor intersect at the boundary of the scanning circle, and the ubiquitous sensing full coverage and the multiple coverage of the GEO space debris in one day are realized together with the morning-evening sun synchronous track observation platform in the first step and the non-morning-evening sun synchronous track observation platform in the second step.

In the first step, the distance difference of the observation platform where the adjacent star sensors are located is smaller than or equal to a distance threshold. The observation platforms are distributed at equal intervals or approximately at equal intervals.

In the first step, the sun synchronous track in the morning and evening is in a height interval of 300km to 2000km, the variation range of the track inclination angle i is 96.67 degrees to 104.89 degrees, and the value of declination of the center of a scanning circle of a GEO belt is-14.89 degrees to-6.67 degrees; the GEO zone is a spherical annular section which takes the earth center as the sphere center, has the orbit height of 36000km and the declination covered by minus 15 degrees to plus 15 degrees.

In the first step, the optical axis direction of the star sensor on the observation platform comprises an elevation angle and an azimuth angle:

in the observation platform orbit coordinate system O _s X _o Y _o Z _o Optical axis L of middle and star sensor _obs And observation platform orbit sub-coordinate system Z _o O _s Y _o The included angle of the plane is an azimuth angle A _z In the orbital coordinate system Z of the observation platform _o O _s Y _o Projection of plane and Y _o The included angle of the axis negative direction is an elevation angle E _l Near to Z _o The positive direction of the shaft is negative, otherwise, the positive direction is positive;

the star sensor optical axis pointing optimal elevation angle of the observation platform is the elevation angle of the critical value with the shortest full coverage time of the star sensor to the GEO band; the optimal azimuth angle is the azimuth angle of the critical value with the shortest full coverage time of the star sensor to the GEO band.

In the first step, the star sensor is pointed to the middle elevation angle E of the optical axis _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And azimuth angle A _z Calculated radius of the scan circle R _s Comprises the following steps:

wherein,

for the elevation angle E in the optical axis direction of the star sensor _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And orientationAngle A _z The radius of the calculated scanning circle;

Indicating GEO band on E ₂ Point to D ₂ The distance of the points; wherein D is ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system, E ₂ For the optical axis of the star sensor at XO _E The intersection point of the projection on the Y plane and the equator; o is _E Is the earth's centroid; r _s1 Is the azimuth angle A in the optical axis direction of the star sensor _z Angle of elevation E when =0 ° _l The radius of the calculated scanning circle; alpha is alpha _s A long semi-axis of a track of an observation platform; alpha is alpha _t The GEO is provided with a long half shaft.

In the first step, the azimuth angle A in the optical axis direction of the star sensor _z Angle of elevation E when =0 DEG _l Calculated radius of the scan circle R _s1 Comprises the following steps:

wherein < A > ₁ O _E C ₁ Is the azimuth angle A in the optical axis direction of the star sensor _z Angle of elevation E when =0 DEG _l The radius of the calculated scanning circle; alpha (alpha) ("alpha") _s A long semi-axis of a track of an observation platform; alpha is alpha _t A GEO with a long half shaft; ejection method of small arc A ₁ O _E B ₁ Expressed in terms of the earth's centroid O _E Is a vertex, A ₁ O _E And O _E B ₁ Angle of (A) ₁ Is the intersection point of the star sensor optical axis and the GEO band, B ₁ Is O _s Y _o The intersection of the reverse extension line and the GEO band.

In the first step, the star sensor is pointed to the middle elevation angle E of the optical axis _l When =0 °, measured by azimuth angle a _z Calculated radius of the scan circle R _s2 Comprises the following steps:

wherein,

elevation angle E for pointing of optical axis of star sensor _l Angle of orientation A when = 0% _z The radius of the calculated scanning circle;

Indicating GEO band at E ₂ Point to D ₂ The distance of the points;

Indicating GEO band on E ₂ Point to C ₂ The distance of the points; d ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system; e ₂ For the optical axis of the star sensor at XO _E The intersection point of the projection on the Y plane and the equator; o is _E Is the earth's centroid; c ₂ Is elevation angle E _l When the angle is 0 degrees, the optical axis of the star sensor points to the intersection point of the GEO band; alpha is alpha _t A long half shaft is provided for GEO; alpha is alpha _s The long half shaft of the orbit of the observation platform.

In the first step, when the number of observation platforms on the scan circle is even, the minimum number of observation platforms ensuring full coverage of GEO space debris in one day is:

wherein,

when the number of observation platforms on the scanning circle is even, the minimum number of observation platforms for ensuring the full coverage of GEO space debris in one day is ensured; n' represents the number of the rotating fields on the scanning circle in the process that GEO space debris runs from west to east; omega _t Is the GEO space debris angular velocity; r is _s Is the radius of the scanning circle; the size of the field of view of the star sensor is n multiplied by n, n is an arbitrary numerical value taking an angle as a unit, the field of view of different star sensors is different in size and is determined by the design of an optical system;

when the number of observation platforms on the scanning circle is odd, the minimum number of observation platforms ensuring that the GEO space debris is fully covered in one day is as follows:

wherein,

when the number of observation platforms on the scanning circle is odd, ensuring the minimum number of observation platforms for ensuring the full coverage of GEO space debris in one day; n' represents the number of the rotating fields on the scanning circle in the process that GEO space debris runs from west to east; omega _t Is the GEO space debris angular velocity; r _s Is the radius of the scanning circle; omega _s The angular velocity of the observation platform; the size of the view field of the star sensor is n multiplied by n, n is an arbitrary numerical value taking an angle as a unit, the view fields of different star sensors are different in size, and the view field is determined by the design of an optical system. />

Preferably, in a 2 ° × 2 ° field of view, when the number of uniformly distributed platforms of the sun synchronization orbit is 5 in the morning and evening, the coverage of the GEO-belt in one day is 99.9%, and the requirement of full coverage is approximately met.

In the first step, the track swept by the star sensor in the GEO spherical annular section is spiral.

The sun synchronous orbit is an orbit in which the precession angular velocity of an orbit surface is equal to the annual apparent motion velocity of the average sun under the shooting condition of the spacecraft. Including morning and evening sun synchronous tracks and non-morning and evening sun synchronous tracks. The morning and evening sun synchronous orbit is an orbit of which the sun synchronous orbit is positioned on the earth morning and evening line.

The cross observation mode in the second step comprises the following steps: the optical axis of the star sensor of the observation platform on the west side track of the non-morning and evening sun synchronous track points to the east side area of the scanning circle, the optical axis of the star sensor of the observation platform on the east side track of the non-morning and evening sun synchronous track points to the west side area of the scanning circle, and the optical axis of the star sensor on the observation platform of the non-morning and evening sun synchronous track points to the boundary of the scanning circle in the direction opposite to the direction of the observation platform of the non-morning and evening sun synchronous track.

In the second step, the pointing direction of the optical axis of the star sensor on the observation platform in the non-morning and non-evening sun synchronous orbit height interval is specifically as follows:

wherein beta is _s Is the pointing angle of the star sensor, a _t With the half-axis of length, θ, for GEO _E For observing the track surface and O of the platform _E Angle of X axis, O _E Is the earth's centroid; r _s For the radius of the scanning circle when neither the elevation nor the azimuth is 0,

the long half shaft of the orbit of the observation platform.

In the third step, the track inclination angle of the inclined track is between 0 and 90 degrees; the installation direction limit range of the star sensor is 30-80 degrees.

The invention has the beneficial effects that:

the invention discloses a ubiquitous sensing observation method of a low-orbit multi-observation platform for GEO space debris, which is used for constructing a ubiquitous sensing observation configuration mainly comprising a morning-and-evening sun synchronous orbit observation platform and supplementing a non-morning-and-evening sun synchronous orbit observation platform and an inclined orbit observation platform aiming at an observation scene of a low-orbit different orbit type spacecraft platform for high-orbit GEO space debris;

in the morning and evening sun synchronous orbit height interval, different numbers of evenly distributed spacecrafts which run on the same orbit height are used as observation platforms, the optical axis directions of star sensors on the observation platforms are set to be consistent, so that a scanning circle which takes any point on 90-i declination as a circle center and is constructed based on the optical axis directions of the star sensors and can cover the boundary of the GEO zone as a radius is formed on the GEO zone; scanning tracks of a plurality of spacecrafts on the GEO belt are overlapped, so that ubiquitous perception observation foundation coverage of GEO space debris is realized; wherein i is the track inclination angle of the synchronous track of the morning and evening sun where the observation platform is;

the observation platform in the non-morning-evening sun synchronous track height interval adopts a cross observation mode, so that the star sensor on the observation platform on the non-morning-evening sun synchronous track points to the reverse scanning circle boundary of the track position where the observation platform is located, and the view field of the non-morning-evening sun synchronous track star sensor and the view field of the morning-evening sun synchronous track star sensor are in an arc section intersected at the scanning circle boundary to form ubiquitous sensing three-dimensional observation and basic coverage supplement for GEO space debris;

setting the optical axis direction of a star sensor on an inclined track observation platform to be not collinear with the vector of a connecting line from the geocenter to the observation platform; the oblique orbit star sensor field of view and the arc section of the non-morning and evening sun synchronous orbit star sensor field of view intersected at the scanning circle boundary, and the oblique orbit star sensor field of view, the non-morning and evening sun synchronous orbit star sensor field of view and the arc section of the morning and evening sun synchronous orbit star sensor field of view intersected at the scanning circle boundary form another supplement for covering the ubiquitous sensing observation foundation of the GEO space debris, and the ubiquitous sensing full coverage and the multiple coverage of the GEO space debris in one day are realized together with the morning and evening sun synchronous orbit observation platform and the non-morning and evening sun synchronous orbit observation platform.

In engineering, a spacecraft with a similar orbit position as that in the step one can be selected as an observation platform to form a scanning circle observation configuration formed by a morning and evening sun synchronous orbit observation platform, even if the observation platform is possibly distributed on the morning and evening sun synchronous orbit in an unequal phase and uniform manner, the neutral position caused by unequal phase can be filled by using the quantity advantage and a larger star sensor view angle, and the requirement of full coverage of GEO space debris within 24 hours is approximately met. And then, adding an observation platform with a non-morning-evening sun synchronous track and an inclined track as auxiliary according to the second step and the third step. Wherein, morning and evening sun synchronous orbit's observation platform is used for realizing quick multiple full coverage to the GEO area, is the basis of whole ubiquitous perception observation configuration. The observation platform of the non-morning and evening sun synchronous track and the inclined track can make the star sensor field of view of the non-morning and evening sun synchronous track and the star sensor field of view of the morning and evening sun synchronous track intersect in an arc section, so that space debris three-dimensional observation is formed at two sides of the east-west boundary of the scanning circle, the revisit degree of observation is increased, and good observation data are provided for subsequent track determination. The observation platform on the non-morning-evening sun synchronous track provided by the step two inherits the good shooting motion characteristic of the sun synchronous track, namely the shooting precession angular speed of the track surface is equal to the annual motion of the sun, so that the observation platform has a good illumination condition advantage, can always keep a favorable observation position in the space, and is a basic configuration for forming space debris three-dimensional observation. The inclined track provided by the step three does not have the shooting motion advantage of the sun synchronous track, so that the stable spatial relative position relation cannot be kept all the time, and the inclined track observation platform mainly plays a role in supplementary observation. The method comprises the following specific steps:

and in the second step, the phase distribution of the observation platforms on the non-morning-evening sun synchronous track in the space is relatively random and may not be uniformly distributed, and as the observation platforms on the non-morning-evening sun synchronous track move along with the track of the observation platforms, after the field of view of the star sensor of the current observation platform slides across the east-west boundary of the scanning circle, the next observation platform does not move in place, so that the star sensor of the current observation platform cannot be constantly kept at the two sides of the east-west boundary of the scanning circle to form three-dimensional observation on space debris. The observation platform on the inclined track thus functions as: firstly, the neutral position of the observation configuration in the first step and the second step is filled as much as possible, so that the stereoscopic observation opportunity is increased; and secondly, the number of platforms and observation revisit degree of a stereo observation arc section are increased, and data support is provided for space debris synchronous positioning based on multi-platform observation data.

In conclusion, a ubiquitous perception observation configuration of the GEO space debris by the low rail mainly comprising the morning and evening sun synchronous rail observation platform and supplemented by the non-morning and evening sun synchronous rail and the inclined rail can be constructed.

In the operation process, each platform can download observation data (right ascension, declination and observation time of the space debris) to a ground data processing center through an inter-satellite link and an inter-satellite link, and can also perform independent analysis and processing on the satellite to complete the track determination and cataloguing work of the space debris, so that the observation capability of the space debris is greatly improved.

The Ubiquitous word is originated from Latin 'Ubiquitous' and means 'Ubiquitous', the star sensor is used as a posture sensor which is necessary for most spacecrafts, if the star sensor is used as a 'dual-purpose' space posture sensing sensor, the advantage of large resource quantity of the on-orbit spacecrafts in China can be fully exerted in the invention, the mounting angle of the star sensor is adjusted on the basis of a disclosed model, the observation configuration of a sun synchronous orbit to a GEO orbit is constructed, the residual value of a large number of on-orbit spacecrafts in China can be further excavated, particularly, a large number of low-orbit spacecrafts are provided, as many spacecrafts with the star sensor as possible are used as observation platforms, the advantage of a space-based observation system is further expanded, a special spacecraft does not need to be additionally launched, the space posture sensing capability of China is greatly improved, the space debris early warning and collision avoidance capability is remarkably enhanced, and suggestions with operability and compatibility are provided for the design of space mission planning in the future.

Drawings

The invention is explained in more detail below with reference to the figures and examples.

FIG. 1 is a schematic view of a non-sun-synchronous orbit observable window.

Fig. 2 is a schematic view of the spatial viewing geometry (north pole top view).

Fig. 3 is a schematic diagram of a simulation scenario (north pole top view).

FIG. 4a is a graph showing the time-varying curves of the GEO target stars and the like on the summer solstice.

FIG. 4b is a graph showing the GEO target star etc. in spring minutes and days as a function of time.

FIG. 5 is a schematic view of the optical axis orientation of the star sensor on the observation platform.

Fig. 6 is a schematic view of the geometry of the scan circle in combination with elevation and azimuth.

Fig. 7 is a schematic view of the geometry of the scanning circle for elevation-only correspondence.

Fig. 8 is a schematic view of the geometry of the scan circle for only azimuth correspondence.

Fig. 9 is an oblique view of a scan circle viewing configuration.

FIG. 10 is a schematic diagram of the relative motion of the target and the scan circle.

FIG. 11 is a schematic diagram of the relative motion trajectory of the star sensor and the GEO strip.

FIG. 12 is a top view of a north pole of a non-morning-and-evening sun-synchronous orbit observation configuration.

Fig. 13 is a schematic diagram of the installation orientation of the sun synchronous orbit star sensor in the non-morning and non-evening.

FIG. 14 is a schematic view of 12 observation platforms located at different inclination angles of inclined tracks.

FIG. 15 is a schematic diagram of a ubiquitous sensing observation configuration for GEO zones, which is composed of low-orbit multi-observation platforms.

FIG. 16 is a time of coverage of different latitudes of the GEO zone over a day for ubiquitous perception of observation configurations.

FIG. 17 is a time of coverage of GEO bands with different longitudes over a day with ubiquitous awareness of observation configurations.

FIG. 18 is a multiple coverage of GEO bands at different latitudes throughout a day sensing observation configuration.

FIG. 19 is a multiple coverage of GEO bands with different longitudes over a day with ubiquitous perception of the viewing configuration.

FIG. 20 is the cumulative coverage of GEO bands over a day of ubiquitous perception of observation configuration.

Detailed Description

The embodiment of the invention discloses a ubiquitous sensing observation method of a low-orbit multi-observation platform for GEO space debris, wherein a star sensor is arranged on the observation platform; the low rail comprises a morning and evening sun synchronous rail, a non-morning and evening sun synchronous rail and an inclined rail; the method comprises the following steps:

step one, in the morning and evening sun synchronous orbit height interval, different numbers of evenly distributed spacecrafts which run on the same orbit height are used as observation platforms, and the optical axis directions of star sensors on the observation platforms are set to be consistent, so that a scanning circle which takes any point on 90-i declination as a circle center and is constructed based on the optical axis directions of the star sensors and can cover the boundary of the GEO zone as a radius is formed on the GEO zone; scanning tracks of a plurality of spacecrafts on the GEO belt are overlapped, so that ubiquitous perception observation foundation coverage of GEO space fragments is realized; wherein i is the track inclination angle of the synchronous track of the morning and evening sun where the observation platform is;

secondly, an observation platform in the non-morning and evening sun synchronous track height interval adopts a cross observation mode, so that a star sensor on the observation platform on the non-morning and evening sun synchronous track points to the reverse scanning circle boundary of the track position of the observation platform, and the field of view of the non-morning and evening sun synchronous track star sensor and the field of view of the morning and evening sun synchronous track star sensor are in an arc section intersected at the scanning circle boundary to form ubiquitous sensing stereo observation and basic coverage supplement for GEO space debris;

setting the optical axis direction of the star sensor on the inclined track observation platform to be not collinear with the vector of a connecting line from the geocenter to the observation platform; the method is characterized in that the arc section of the oblique track star sensor field of view and the arc section of the non-morning and evening sun synchronous track star sensor field of view, which intersect at the scanning circle boundary, of the oblique track star sensor field of view and the arc section of the non-morning and evening sun synchronous track star sensor field of view and the arc section of view and the arc section of the oblique track star sensor field of view and the arc section of view, which intersect at the scanning circle boundary, of the oblique track star sensor field of view, the non-morning and evening sun synchronous track star sensor field of view and the arc section of view of the scanning circle boundary form another supplement for covering the ubiquitous sensing observation foundation of GEO space fragments, and the ubiquitous sensing full coverage and the multiple coverage of the GEO space fragments in one day are realized together with the non-morning and evening sun synchronous track observation platform in the step one and the step two.

According to the technical scheme, for the same number of observation platforms, the observation platforms which are uniformly distributed can enable the whole scanning circle to observe space debris uniformly, and the non-uniform distribution can cause a gap between two certain observation platforms to be larger and certain debris to be missed.

In the scheme, the distance difference of the observation platforms where the adjacent star sensors are located is smaller than or equal to the distance threshold, so that the technical scheme can be implemented when the plurality of observation platforms which are uniformly distributed are distributed at equal intervals or approximately at equal intervals.

In engineering, a spacecraft with a similar rail position as that in the step one can be selected as an observation platform to form a scanning circle observation configuration formed by a morning and evening sun synchronous orbit observation platform, even if the observation platform is possibly distributed uniformly in an unequal phase on the morning and evening sun synchronous orbit, the neutral position caused by unequal phase intervals can be filled by using the quantity advantage and a larger star sensor field angle, and the requirement of full coverage of GEO space fragments within 24 hours is approximately met. And then, adding a non-morning-and-evening sun synchronous rail and an inclined rail as auxiliary observation platforms according to the second step and the third step respectively. Wherein, morning and evening sun synchronous orbit's observation platform is used for realizing quick multiple full coverage to the GEO area, is the basis of whole ubiquitous perception observation configuration. The observation platform of the non-morning and evening sun synchronous track and the inclined track can make the star sensor field of view of the non-morning and evening sun synchronous track and the star sensor field of view of the morning and evening sun synchronous track intersect in an arc section, so that space debris three-dimensional observation is formed at two sides of the east-west boundary of the scanning circle, the revisit degree of observation is increased, and good observation data are provided for subsequent track determination. The observation platform on the non-morning-evening sun synchronous track provided by the step two inherits the good shooting motion characteristic of the sun synchronous track, namely the shooting precession angular speed of the track surface is equal to the annual motion of the sun, so that the observation platform has a good illumination condition advantage, can always keep a favorable observation position in the space, and is a basic configuration for forming space debris three-dimensional observation. The inclined track provided by the step three does not have the shooting motion advantage of the sun synchronous track, so that the stable spatial relative position relation cannot be kept all the time, and the inclined track observation platform mainly plays a role in supplementary observation. The method specifically comprises the following steps:

and in the second step, the phase distribution of the observation platforms on the non-morning-evening sun synchronous track in the space is relatively random and may not be uniformly distributed, and with the orbital motion of the observation platforms on the non-morning-evening sun synchronous track, after the field of view of the star sensor of the current observation platform slides across the east-west boundary of the scanning circle, the next observation platform does not move in place, so that the observation platforms cannot be constantly kept at the two sides of the east-west boundary of the scanning circle to form three-dimensional observation on space debris. The observation platform on the inclined track thus functions as: firstly, the neutral position of the observation configuration in the first step and the second step is filled as much as possible, so that the stereoscopic observation opportunity is increased; and secondly, the number of platforms and observation revisit degree of a stereo observation arc section are increased, and data support is provided for space debris synchronous positioning based on multi-platform observation data.

And in conclusion, a ubiquitous perception observation configuration of the GEO space debris by the low rail, which is mainly based on the morning and evening sun synchronous rail observation platform and supplemented by the non-morning and evening sun synchronous rail and the inclined rail, can be constructed.

As shown in fig. 5, in the first step, the optical axis of the star sensor on the observation platform points to include an elevation angle and an azimuth angle;

in the observation platform orbit coordinate system O _s X _o Y _o Z _o Optical axis L of middle and star sensor _obs And observation platform orbit sub-coordinate system Z _o O _s Y _o The included angle of the plane is an azimuth angle A _z In the orbital coordinate system Z of the observation platform _o O _s Y _o Projection of plane and Y _o The included angle of the axis negative direction is an elevation angle E _l Near to Z _o The positive axis is negative and the opposite is positive.

The optimal elevation angle is the elevation angle of the critical value with the shortest full coverage time of the star sensor to the GEO band; and the optimal azimuth angle is the azimuth angle of the critical value with the shortest full coverage time of the star sensor to the GEO band.

In step one, as shown in figure 6,

correspond to FIG. 7Is/are>

Is triangular on the spherical surface>

And &>

Middle and elevation angle E _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And azimuth angle A _z Calculated radius of the scan circle R _s Comprises the following steps:

wherein,

is elevation angle E _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And azimuth angle A _z The calculated radius of the scanning circle;

For GEO with E ₂ Point to D ₂ Distance of points, wherein D ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system, E ₂ For the optical axis of the star sensor at XO _E The intersection point of the projection on the Y plane and the equator; o is _E Is the earth's centroid; r is _s1 Is an azimuth angle A _z Angle of elevation E when =0 DEG _l The calculated radius of the scanning circle; alpha is alpha _s A long semi-axis of a track of an observation platform; alpha (alpha) ("alpha") _t The GEO is provided with a long half shaft.

As shown in fig. 7, the azimuth angle a _z Angle of elevation E when =0 DEG _l Calculated radius of the scan circle R _s1 Comprises the following steps:

then at Δ A ₁ O _s O _E In the middle, easy to obtain:

in a similar manner, at Δ B ₁ O _s O _E In the specification, the following are:

combined upper to obtain a radius R _s1 Comprises the following steps:

wherein, angle A ₁ O _E C ₁ Is an azimuth angle A _z Angle of elevation E when =0 DEG _l The calculated radius of the scanning circle; alpha is alpha _s A long semi-axis of a track of an observation platform; alpha (alpha) ("alpha") _t A GEO with a long half shaft; angle A ₁ O _E B ₁ Expressed in terms of the earth's centroid O _E Is a vertex, A ₁ O _E And O _E B ₁ Angle of (A) ₁ Is the intersection point of the optical axis of the star sensor and the GEO band; b is ₁ Is O _s Y _o The intersection point of the reverse extension line and the GEO band; o is _E Is the center of mass of the earth, O _s Is the center of mass of the observation platform;

is a GEO band; o is _s A ₁ Pointing to the optical axis of the star sensor. />

As shown in FIG. 8, O _s C ₂ For the optical axis direction of the star sensor, Z _o O _s Y _o Is a plane in the orbital coordinate system and,

for scanning the radius of the circle, the triangle Δ C on the sphere ₂ E ₂ D ₂ Performing the following steps; elevation angle E _l Angle of orientation A when = 0% _z Calculated radius of the scan circle R _s2 Comprises the following steps:

wherein,

is the radius of the scanning circle;

Indicating GEO band on E ₂ Point to D ₂ The distance of the points;

Indicating GEO band on E ₂ Point to C ₂ The distance of the points; d ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system; e ₂ For the optical axis of the star sensor at XO _E The intersection point of the projection on the Y plane and the equator; c ₂ Is E _l When the angle is not less than 0 degree, the optical axis of the star sensor points to the intersection point of the GEO band; alpha is alpha _t A GEO with a long half shaft; alpha is alpha _s The long half shaft of the orbit of the observation platform.

As shown in fig. 9, taking 12 observation platforms with equal phase difference distribution on the scanning circle as an example, the phase difference between the observation platforms is distributed at equal intervals of 30 °, and the number of the rest tracks is the same except that the true proximal angles of the observation platforms are distributed at equal intervals. The method is an ideal assumed condition, can be customized according to task requirements in engineering practice, and does not require that observation platforms are uniformly distributed at equal intervals. The annular strip is a GEO strip formed within the declination range of +/-15 degrees.

Space debris on the GEO zone naturally moves around the earth from west to east, and in order to enable the space debris to be observed by sensors distributed on a scanning circle at equal intervals at least once in one orbit period, the mathematical problem of a minimum number of observation platforms exists. The following modeling calculations were made:

assuming that a plurality of observation platforms running on the same orbit height are distributed at equal intervals, and the star sensors on each platform have consistent optical axis directions, the scanning tracks of the star sensors on the GEO band are overlapped. The more the number of the observation platforms is, the faster the observation platforms cover the GEO zone is, and the shorter the revisit time is. If the GEO zone is to realize full coverage in one day, the minimum value of the number of observation platforms is set as

The method is not only related to the orbit characteristic of an observation platform, but also related to the field size of the star sensor and the radius of a scanning circle.

Let the view field size of the star sensor be nxn and the angular velocity of the observation platform be omega _s The GEO target angular velocity is omega _t The star sensor has a pointing elevation angle E _l Azimuth angle is A _z Radius of the scanning circle being R _s (angular separation). The following analyses were performed: the GEO target crosses the scan circle twice a day from west to east as shown by the dashed middle line in fig. 10, the critical condition being that the target has a field of view N in fig. 10 ₁ The next time after the passage and in the field of view N ₂ The gap that has not yet arrived enters the scan circle, at which point the field of view N ₂ Angular distance beta from target ₂ . Classification discussion, when the number of observation platforms is even, N exists at the moment ₂ Symmetrical field of view N _j When the target runs to the east boundary of the circle, the corresponding field of view N _k And N _k+1 ，β _k 、β _k+1 Is the angular separation of the two. To ensure that an object is detected, the following relationship exists:

at the west side of the scan circle, the angular separation β ₂ Can be expressed as:

the target is from west to east, and the operation process from entering the scanning circle to entering the east side scanning visual field satisfies the following relation:

where N' represents the number of fields of view that the scan circle has rotated during the west-to-east operation of the target. On the east side of the scan circle, the following relationship holds:

wherein the inequality constrains the target to enter N _k+1 Angular distance beta to be satisfied by field of view _k+1 The upper bound of (c). In summary, it can be determined that when the number of observation platforms on the scan circle is even, the minimum number of observation platforms that ensure full coverage of GEO space debris during a day is:

wherein,

when the number of observation platforms on the scanning circle is even, the minimum number of observation platforms ensuring that the GEO space debris is fully covered in one day is; n' represents the number of the rotating view fields on the scanning circle in the process of running the GEO space target from west to east; omega _t Is the GEO space target angular velocity; r _s Is the radius of the scanning circle; omega _s The angular velocity of the observation platform; the size of the field of view of the star sensor is n multiplied by n, n is an arbitrary numerical value taking an angle as a unit, the field of view of different star sensors is different in size and is determined by the design of an optical system;

when the number of the observation platforms is odd, the observation platforms and the field of view N ₂ Symmetric is the field of view N _i And N _i+1 The equation (2-51) becomes:

wherein,

when the number of observation platforms on the scanning circle is odd, the minimum number of observation platforms ensuring that the GEO space debris is fully covered in one day is; n' represents the number of the rotating view fields on the scanning circle in the process of running the GEO space target from west to east; omega _t Is the GEO space target angular velocity; r is _s Is the radius of the scanning circle; omega _s To observe the angular velocity of the platform; the size of the view field of the star sensor is n multiplied by n, n is an arbitrary numerical value taking an angle as a unit, the view fields of different star sensors are different in size, and the view field is determined by the design of an optical system.

The above model determines the minimum number of observation platforms on a scan circle that will allow a GEO-strip to achieve full coverage in a day. The above formula provides theoretical values for reference, the modeling process is based on certain assumptions, namely the heights of the tracks of the observation platforms are consistent and have the same phase difference, in the engineering, the tracks of the observation platforms are determined according to the task requirements of the observation platforms and cannot be completely consistent, but in the common track height range, the track inclination angle change of the sun synchronous track is very small, namely the circle center of the scanning circle does not have large fluctuation.

The track swept by the star sensor in the GEO spherical annular tangent plane is spiral.

In practice, as shown in fig. 11, the trajectory swept by the star sensor in the plane of the GEO zone is helical, due to the relative movement between the GEO zone itself and the plane of the observation trajectory. The coverage of the field of view of the star sensor on the GEO zone is realized through the spiral relative motion relationship, the orbit height of the observation platform and the installation direction of the star sensor can be reasonably designed, and the spiral scans of a plurality of circles are not repeatedly superposed with each other as far as possible, so that the quick full coverage of space fragments of the GEO zone is realized in a short time.

In the past, the space-based sensing system mostly adopts a follow-up tracking observation mode, namely, a sensor is controlled to observe along with a target through a two-dimensional turntable, the observation arc section is long, and the efficiency is high; however, the star sensor is used as a 'dual-purpose' sensor, the possibility of follow-up tracking does not exist, and the general scanning of the GEO band can be performed only in a natural intersection mode. At the moment, the platform of which tracks is selected to be used as an observation platform, and how to obtain good observation efficiency by adjusting the installation direction under the condition of not influencing the normal work of the star sensor is very important. The scanning circle observation model designed by the scheme can fully utilize good illumination observation conditions, forms a spiral observation form along with the movement of the GEO zone, and establishes the corresponding relation between the star sensor installation direction, the observation platform track height and the observation coverage percentage.

In the second step, in order to ensure that the space observation geometry has a longer baseline, which is beneficial to the application of the subsequent observation data in the track determination field, on the basis of not affecting the imaging of the star sensor on the starry sky background, the observation platform on the non-morning-evening sun synchronous track is particularly set to adopt a cross observation mode, as shown in fig. 12, that is, the star sensor of the observation platform on the west side track points to the east region of the scanning circle, while the star sensor of the observation platform on the east side points to the west region of the scanning circle, so that the optical axis of the star sensor on the observation platform on the non-morning-evening sun synchronous track points to the boundary of the scanning circle in the direction opposite to that of the observation platform on the non-morning-evening sun synchronous track.

And in the second step, the rising intersection point right ascension of the non-morning and non-evening sun synchronous track is not restricted, and the optical axis direction of the star sensor on the observation platform is adjusted only before emission.

Fig. 13 is a top view of the earth's north celestial pole, which is the same in the opposite direction, for example, the east observation platform star sensor points to scan the boundary region of the west circle. The pointing direction of the optical axis of the star sensor on the observation platform in the non-morning-and-evening sun synchronous track height interval is specifically as follows:

wherein beta is _s Is the pointing angle of the star sensor, a _t With the half-axis of length, θ, for GEO _E For observing the track surface of the platformO _E Angle of X axis, O _E Is the earth's centroid; r _s Is the radius of the scanning circle when neither the elevation nor the azimuth is 0,

in order to observe the long half shaft of the platform track,

for the mass center of the observation platform spacecraft which is not in the morning and evening and is on the sun synchronous orbit>

The central field of view point of the west boundary of the circle is scanned for the GEO zone.

In step three, the so-called inclined orbit is an orbit with the inclination angle of the orbit between 0 and 90 degrees, and the spacecraft running on the orbit is distributed in the near-earth space. The invention has no special requirements on the number of the track such as the track inclination angle, the track height, the ascension point right ascension, the argument of the near place and the like of the inclined track, and only limits the installation direction of the star sensor to a certain degree, namely the direction of the optical axis of the star sensor of the inclined track is not collinear (generally 30-80 degrees) with the connecting line vector of the geocentric and the observation platform. Fig. 14 shows 12 cases of observation platforms located at different tilt angles of the inclined orbit.

In conclusion, a ubiquitous sensing observation configuration of the low rail to the GEO space debris, which is mainly based on the morning and evening sun synchronous rail observation platform and supplemented by the non-morning and evening sun synchronous rail and the inclined rail, can be constructed, as shown in fig. 15.

Simulation analysis of the embodiment:

setting simulation starting time to be 2024, 3 month and 21 days, selecting 12 morning and evening sun synchronous tracks, 12 common sun synchronous tracks and 12 inclined track observation platforms (track inclination angles are respectively 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 65 degrees, 70 degrees and 75 degrees), and forming the space debris ubiquitous sensing observation configuration based on the star sensor natural intersection mode. Wherein, the heights of the sun synchronous orbits in the morning and evening are respectively 500 km-700 km, and the ascent points of the other sun synchronous orbits are randomly distributed. For the observation configuration, the observation efficiency is evaluated from two aspects, namely the coverage time and the full coverage time of the observation configuration on different latitude and longitude day domains of the GEO band, and the multiple coverage degree of the observation configuration on different latitude and longitude day domains of the GEO band.

The simulation results are as follows: see fig. 16, 17, 18, 19 and 20.

Fig. 16 and 17 show the maximum, minimum and average coverage time lengths of different latitude and longitude areas of the GEO band by the ubiquitous sensing observation configuration, respectively. As can be seen, the average observation time of 24 hours in different latitude zones is about 1 to 1.5 hours, and the maximum observation time exceeds 3 hours; the average observation time of 24 hours of different longitude zones is about 1.5 hours, and the maximum observation time is also more than 3 hours.

Fig. 18, 19 show the maximum, minimum and average coverage of different latitude, longitude regions on the GEO-band by ubiquitous perceptual observation configurations. Therefore, the average coverage of different latitudes is about 2, and 5 star sensors can cover the latitude at the same time. Coverage for different longitudes is similar, with the difference that the longitude bands with maximum coverage of 5 and 4 range more narrowly, and the average coverage fluctuates more strongly with the abscissa.

Fig. 20 shows the percentage of GEO-strip covered in 24 hours, showing that the early-stage percentage of coverage increased faster, and that the percentage of coverage approached 100% after about 20 hours, which is a ubiquitous perceptual observation configuration that achieves full coverage of GEO-strip in one day.

In conclusion, the simulation result is used for displaying the response time of the observation configuration to the full coverage of the GEO band during coverage, and the multiple coverage is used for displaying the condition that the same area is captured by a plurality of star sensors at the same time, which is one of the important characteristics that the star sensors sense different from other space-based observation systems, and the advantage of the number of observation platforms is fully exerted, so that the single target can be stereoscopically observed by a plurality of platforms.

It should be noted that all the above analyses are established on the basis of the number of observation platforms stated initially in the simulation, and only for evaluating the observation efficiency and effectiveness of the natural intersection observation configuration of the space-based multi-platform solar synchronous orbit provided by the invention, the method of the invention is not limited to the number of platforms described herein, but can be continuously expanded. In engineering, by combining the actual observation platform track and the star sensor direction, the observation efficiency may have slight difference. Considering that the number of star sensors installed on most spacecrafts is more than one, the observation efficiency is further improved if more star sensors and spacecrafts which are possibly launched in the future are brought into the observation configuration.

The embodiment of the invention has the beneficial effects that:

the embodiment of the invention discloses a ubiquitous sensing observation method of a low-orbit multi-observation platform for GEO space debris, which is used for constructing a ubiquitous sensing observation configuration mainly comprising a morning and evening sun synchronous orbit observation platform and supplementing a non-morning and evening sun synchronous orbit observation platform and an inclined orbit observation platform aiming at an observation scene of a low-orbit different orbit type spacecraft platform for high-orbit GEO space debris;

in the morning and evening sun synchronous orbit height interval, different numbers of evenly distributed spacecrafts which run on the same orbit height are used as observation platforms, the optical axis directions of star sensors on the observation platforms are set to be consistent, so that a scanning circle which takes any point on 90-i declination as a circle center and is constructed based on the optical axis directions of the star sensors and can cover the boundary of the GEO zone as a radius is formed on the GEO zone; scanning tracks of a plurality of spacecrafts on the GEO belt are overlapped, so that ubiquitous perception observation foundation coverage of GEO space fragments is realized; wherein i is the track inclination angle of the morning and evening sun synchronous track where the observation platform is located;

the observation platform in the non-morning-evening sun synchronous track height interval adopts a cross observation mode, so that the star sensor on the observation platform on the non-morning-evening sun synchronous track points to the reverse scanning circle boundary of the track position where the observation platform is located, and the view field of the non-morning-evening sun synchronous track star sensor and the view field of the morning-evening sun synchronous track star sensor are in an arc section intersected at the scanning circle boundary to form ubiquitous sensing three-dimensional observation and basic supplement for GEO space fragments;

In engineering, a spacecraft with a similar orbit position as that in the step one can be selected as an observation platform to form a scanning circle observation configuration formed by a morning and evening sun synchronous orbit observation platform, even if the observation platform is possibly distributed on the morning and evening sun synchronous orbit in an unequal phase and uniform manner, the neutral position caused by unequal phase can be filled by using the quantity advantage and a larger star sensor view angle, and the requirement of full coverage of GEO space debris within 24 hours is approximately met. And then, adding an observation platform with a non-morning-evening sun synchronous track and an inclined track as auxiliary according to the second step and the third step. Wherein, morning and evening sun synchronous orbit's observation platform is used for realizing fast multiple full coverage to the GEO area, is the basis of whole ubiquitous perception observation configuration. The observation platform of the non-morning and evening sun synchronous track and the inclined track can make the star sensor field of view of the non-morning and evening sun synchronous track and the star sensor field of view of the morning and evening sun synchronous track intersect in an arc section, so that space debris three-dimensional observation is formed at two sides of the east-west boundary of the scanning circle, the revisit degree of observation is increased, and good observation data are provided for subsequent track determination. The observation platform on the non-morning-evening sun synchronous track provided by the step two inherits the good shooting motion characteristic of the sun synchronous track, namely the shooting precession angular speed of the track surface is equal to the annual motion of the sun, so that the observation platform has a good illumination condition advantage, can always keep a favorable observation position in the space, and is a basic configuration for forming space debris three-dimensional observation. The inclined track provided by the step three does not have the shooting motion advantage of the sun synchronous track, so that the stable spatial relative position relation cannot be kept all the time, and the inclined track observation platform mainly plays a role in supplementary observation. The method specifically comprises the following steps:

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A ubiquitous sensing observation method of a low-rail multi-observation platform for GEO space debris is disclosed, wherein the low rail comprises a morning and evening sun synchronous rail, a non-morning and evening sun synchronous rail and an inclined rail; the method is characterized by comprising the following steps:

setting the optical axis direction of a star sensor on the inclined track observation platform to be not collinear with the vector of a connecting line from the geocenter to the observation platform; the method is characterized in that the arc section of the oblique track star sensor field of view and the arc section of the non-morning and evening sun synchronous track star sensor field of view, which intersect at the scanning circle boundary, of the oblique track star sensor field of view and the arc section of the non-morning and evening sun synchronous track star sensor field of view and the arc section of view and the arc section of the oblique track star sensor field of view and the arc section of view, which intersect at the scanning circle boundary, of the oblique track star sensor field of view, the non-morning and evening sun synchronous track star sensor field of view and the arc section of view of the scanning circle boundary form another supplement for covering the ubiquitous sensing observation foundation of GEO space fragments, and the ubiquitous sensing full coverage and the multiple coverage of the GEO space fragments in one day are realized together with the non-morning and evening sun synchronous track observation platform in the step one and the step two.

2. The method of claim 1, wherein in the first step, the distance difference between the observation platforms of the adjacent star sensors is less than or equal to a distance threshold.

3. The method as claimed in claim 1, wherein in the first step, the sun-synchronous orbit in the morning and evening is in the range of 300km to 2000km in height, the inclination angle i of the orbit ranges from 96.67 ° to 104.89 °, and the declination of the center of the scanning circle of the GEO zone ranges from-14.89 ° to-6.67 °; the GEO zone is a spherical annular section which takes the earth center as the sphere center, has the orbit height of 36000km and the declination covered by minus 15 degrees to plus 15 degrees.

4. The method of claim 1, wherein in the first step, the optical axis of the star sensor on the observation platform is directed to include an elevation angle and an azimuth angle:

5. The method of claim 4, wherein in the first step, the star sensor has an optical axis pointing at an elevation angle E _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And azimuth angle A _z Calculated radius of the scan circle R _s Comprises the following steps:

wherein,

for the elevation angle E in the optical axis direction of the star sensor _l And azimuth angle A _z All are not 0 degree, from elevation angle E _l And azimuth angle A _z The radius of the scanning circle is calculated;

Indicating GEO band on E ₂ Point to D ₂ The distance of the points; wherein D is ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system, E ₂ For the star sensor optical axis at XO _E The intersection point of the projection on the Y plane and the equator; o is _E Is the earth's centroid; r is _s1 Is the azimuth angle A in the optical axis direction of the star sensor _z Angle of elevation E when =0 ° _l The radius of the calculated scanning circle; alpha is alpha _s A long semi-axis of a track of an observation platform; alpha is alpha _t The GEO is provided with a long half shaft.

6. The method of claim 4, wherein in the first step, the star sensor has an azimuth angle A in the optical axis direction _z Angle of elevation E when =0 ° _l Calculated radius of the scan circle R _s1 Comprises the following steps:

wherein, angle A ₁ O _E C ₁ Is the azimuth angle A in the optical axis direction of the star sensor _z Angle of elevation E when =0 ° _l The radius of the scanning circle is calculated; alpha (alpha) ("alpha") _s A long semi-axis of a track of an observation platform; alpha is alpha _t A GEO with a long half shaft; angle A ₁ O _E B ₁ Expressed in terms of the earth's centroid O _E Is a vertex, A ₁ O _E And O _E B ₁ Angle of (A) ₁ Is the intersection point of the star sensor optical axis and the GEO band, B ₁ Is O _s Y _o The intersection of the reverse extension line and the GEO band.

7. The method of claim 4, wherein in the first step, the star sensor has an optical axis pointing at an elevation angle E _l Angle of orientation A when = 0% _z Calculated radius of the scan circle R _s2 Comprises the following steps:

wherein,

for the elevation angle E in the optical axis direction of the star sensor _l Angle of orientation A when = 0% _z The radius of the calculated scanning circle;

indicating GEO band on E ₂ Point to D ₂ The distance of the points;

Indicating GEO band on E ₂ Point to C ₂ The distance of the points; d ₂ Is the intersection point of the X axis and the equator in the celestial coordinate system; e ₂ For the star sensor optical axis at XO _E Intersection point of projection on Y plane and sky equator; o is _E Is the earth's centroid; c ₂ Is elevation angle E _l When the angle is not less than 0 degree, the optical axis of the star sensor points to the intersection point of the GEO band; alpha (alpha) ("alpha") _t A GEO with a long half shaft; alpha (alpha) ("alpha") _s For observing the long half shaft of the platform track.

8. The method of claim 1, wherein in the first step, when the number of observation platforms on the scan circle is even, the minimum number of observation platforms that ensure full coverage of GEO space debris during a day is:

wherein,

wherein,

when the number of observation platforms on the scanning circle is odd, ensuring the minimum number of observation platforms for ensuring the full coverage of GEO space debris in one day; n' represents the number of the view fields rotated on the scanning circle in the process that GEO space debris runs from west to east; omega _t The angular velocity of the GEO space debris; r is _s Is the radius of the scanning circle; omega _s The angular velocity of the observation platform; the size of the view field of the star sensor is n multiplied by n, n is an arbitrary numerical value taking an angle as a unit, the view fields of different star sensors are different in size, and the view field is determined by the design of an optical system.

9. The method of claim 1, wherein the cross observation mode in step two comprises: the optical axis of the star sensor of the observation platform on the west-side track of the non-morning-and-evening sun synchronous track points to the east-side area of the scanning circle, and the optical axis of the star sensor of the observation platform on the east-side track of the non-morning-and-evening sun synchronous track points to the west-side area of the scanning circle, so that the optical axis of the star sensor on the observation platform of the non-morning-and-evening sun synchronous track points to the boundary of the scanning circle in the direction opposite to the direction of the observation platform of the non-morning-and-evening sun synchronous track.

10. The method according to claim 1 or 9, wherein in the second step, the optical axis of the star sensor on the observation platform in the non-morning and non-evening sun synchronous orbit height interval is pointed specifically as follows:

wherein, beta _s Is the pointing angle of the star sensor, a _t With the half-axis of length, θ, for GEO _E For observing the track surface and O of the platform _E Angle of X axis, O _E Is the earth's centroid; r _s For the radius of the scanning circle when neither the elevation nor the azimuth is 0,

the long half shaft of the orbit of the observation platform. />