A side-by-side multi-satellite formation method capable of real-time high-precision relative measurement

Abstract

The application provides a side-by-side multi-satellite formation method capable of real-time high-precision relative measurement, establishes a relative motion model of the formation multi-satellite based on the orbit kinematics theory, obtains a mathematical expression of the relationship between the baseline vector and the six elements of the orbit by deduction and simplification, and establishes a direct corresponding relationship between the baseline requirement of the formation system and the orbit parameters; a constraint relationship of the field of view requirement of the baseline measurement system to the baseline vector is established, the constraint relationship and the baseline expression are applied to the orbit parameter design of the formation satellite, and the orbit real-time adjustment criterion is obtained by applying the constraint relationship and the baseline expression to the orbit maintenance strategy design, so that the inter-satellite measurement can be realized at any time of the formation system. The method constructed by the application can solve the orbit and configuration design of the distributed multi-satellite formation system facing the inter-satellite baseline requirement, simultaneously solve the baseline common-view blocking problem of the formation system in operation, and can realize the on-orbit autonomous task planning and execution in the whole process of the on-orbit operation, so that the efficiency and speed are high, the task is flexible to respond, and the method has practical engineering significance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of real-time high-precision relative measurement side-by-side multi-star formation method, belong to space technology field. BACKGROUND

[0002] The inter-satellite baseline measurement of distributed satellite formation needs to measure multiple baselines formed by two satellites in observation formation simultaneously.The baseline measurement method based on GNSS measurement currently applied in orbit cannot meet the demand of three-dimensional imaging application in terms of accuracy, and the laser / visual measurement method is introduced on this basis, which can greatly improve the measurement accuracy by using the accurate measurement of the position of the line-of-sight target within the field of view of the measurement system. In the face of multi-star formation system with more than two stars, the formation satellites may be arranged in a linear array during flight. Due to the shielding of the middle satellite, the two end satellites are in a common view shielding state, so the laser and visual measurement system cannot complete the baseline measurement of the two far-end satellites. SUMMARY

[0003] The technical problem solved by the present application is to overcome the shortcomings of the prior art and provide a kind of real-time high-precision relative measurement side-by-side multi-star formation method. The inter-satellite baseline mathematical model is established using space relative kinematics model, the corresponding relationship between baseline and orbit six elements is established, and it is used as the basis for formation configuration design and real-time adjustment of formation satellites in orbit, providing a solution to avoid the common view shielding condition during multi-star multi-baseline measurement.

[0004] The technical solution of the present application is: a kind of real-time high-precision relative measurement side-by-side multi-star formation method, comprising:

[0005] The mathematical model of relative motion of multi-star formation is established based on the theory of orbit kinematics, the inter-satellite baseline mathematical model is established by simplifying and deducing relative motion, the mathematical expression of the relationship between baseline vector and orbit six elements is obtained, and the direct correspondence between baseline requirements and orbit parameters of formation system is established;

[0006] The constraint relationship of baseline vector is established based on the field of view requirement of baseline measurement system;

[0007] During formation configuration and orbit design, two satellites in multi-star distributed formation are a group, the relative orbit parameters of any two satellites in distributed formation are obtained according to the baseline requirements using the corresponding relationship, the relative orbit parameters of the two groups of satellites are corrected using the constraint relationship of baseline vector according to the field of view requirement, one satellite is used as the main star to design the initial parameters of the orbit, and then the initial orbit parameters of the remaining satellites of the formation are obtained according to the above relative orbit parameters;

[0008] During in-orbit operation, the orbital parameters are calculated in real time by GNSS, and the spatial baseline formed by any two satellites in the distributed formation is obtained according to mathematical expressions. The constraint relationship of the baseline vector based on the field of view requirement is used to determine whether there is common view occlusion between multiple sets of baselines formed by multiple satellites. If common view occlusion exists, the orbital parameters of one of the formation satellites are adjusted in orbit based on the constraint relationship of the baseline vector based on the field of view requirement so that any two sets of baselines satisfy the constraint relationship, thereby realizing real-time high-precision relative measurement of multi-satellite formations side by side at any time.

[0009] The mathematical model of relative motion of multiple satellites in formation is established based on orbital kinematics theory. Through the simplified derivation of relative motion, an inter-satellite baseline mathematical model is established, yielding a mathematical expression for the relationship between the baseline vector and the six orbital roots. This establishes a direct correspondence between the baseline requirements of the formation system and the orbital parameters, including:

[0010] Establish the RTN coordinate system of the spacecraft's primary satellite; then, the expression for the relative motion of the slave satellite relative to the primary satellite in the RTN coordinate system is:

[0011] Δr R =a a -a c +a c [-(e a cosω a -e c cosω c cosu c -(e a sinω a -e c sinω c )sinu c ]

[0012]

[0013] Δr N =a c [-(Ω a -Ω c )sini c cosu c +(i a -i c )sinu c ]

[0014] Among them, u c It is the mean latitude argument of the primary star, u c =ω c +M c M c It is the angle of approach, Ω c and r c These are the right ascension of the ascending node and the geocentric distance of the primary star, ic is the inclination of the primary star, e c is the eccentricity of the primary star, a c is the semi-major axis of the primary star; a a , e a , u a , M a , Ω a , i a and r a are the orbital variables of the secondary star, with the same physical meaning as the primary star;

[0015] Let a a -a c = 0, u a -u c = 0, take the virtual star O as the primary star, and the primary star as a circular orbit, e c = 0, simplify the relative motion expression of the secondary star relative to the primary star, and obtain

[0016] Δr R = -a c e a cos(u c -ω a )

[0017] Δr T = 2a c e a sin(u c -ω a )

[0018]

[0019] wherein,

[0020] According to the inter-satellite baseline requirements of the formation system, the normal N direction baseline component is not considered, two satellites M1, S2 of each baseline group are at the two ends of the same straight line with the virtual star O, and the distances of the two satellites from the virtual star O are equal. At this time, the eccentricities of the two satellites need to be equal, i.e. e a1 = e a2 , and the perigee amplitudes of the two satellites are 180° apart, i.e. ω a1 = ω a2 -180°; wherein the subscripts 1 and 2 represent the satellites M1 and S2 in the formation, respectively;

[0021] The component expression of the inter-satellite baseline in the R-T plane of the RTN coordinate system is calculated to obtain the baseline length and the baseline inclination.

[0022] The baseline length and the baseline inclination expressions are respectively:

[0023] The radial R direction baseline length Bz :

[0024] B z = 2Δr R = -2a c e a1 cps(u c - ω a1 ),

[0025] flight direction T direction baseline length B x :

[0026] B x = 2Δr T = 4a c e a1 sin(u c - ω a1 )

[0027] baseline inclination angle α:

[0028]

[0029] α = arctan(-0.5cot(u c - ω a1 )).

[0030] The spacecraft master star RTN coordinate system is established, including: the formation flight relative motion coordinate system is defined, the coordinate system origin is the master star spacecraft, the R direction is the direction of the earth center pointing to the master star, the T direction is the motion direction of the master star, and the N direction is the normal direction of the orbit plane determined by the right hand system.

[0031] The constraint relationship of the baseline vector required by the field of view of the baseline measurement system includes:

[0032] The constraint relationship of the baseline vector required by the field of view of the baseline measurement system is established, with the virtual star O as the center, the formation satellites M1, M3… are located on the same side of the center O, and the formation satellites S2, S4… are located on the other side of the center O, wherein M1, S2 form a space baseline MS1, M3, S4 form a space baseline MS2… and so on; wherein, the expression of the baseline inclination angle difference of the baseline MS1 and the baseline MS2 is as follows:

[0033] Δα = arctan(-0.5cot(u c - ω a3 ))-arctan(-0.5cot(u c - ω a1 ))According to the above rule, the change range of the baseline inclination angle difference Δα is where Δω = ω a3 - ω a1Subscripts 1 and 3 represent satellite M1 and satellite M3, respectively;

[0034] Δα≥θ

[0035] Where θ represents the maximum field of view of the baseline measurement system;

[0036] but,

[0037] Δω=ω a3 -ω a1 ≥2θ;

[0038] That is, the perigee amplitude difference between satellite M3 and satellite M1 must be greater than twice the field of view.

[0039] The process involves obtaining the relative orbital parameters of any two satellites in the distributed formation based on baseline requirements and corresponding relationships. Simultaneously, the relative orbital parameters of the two sets of satellites are corrected using the constraint relationship of the baseline vector based on field-of-view requirements. One satellite is used as the primary satellite to design initial orbital parameters. Based on these relative orbital parameters, the initial orbital parameters of the remaining satellites in the formation are then obtained, including:

[0040] Based on the regression characteristics of remote sensing satellites and the requirements for observation efficiency, the semi-major axis a c The size is given through mission calculations, as are the orbital inclination and right ascension of the ascending node; for any pair of satellites forming the baseline, the maximum baseline length B in the radial R direction is given according to mission requirements. z That is, to obtain the eccentricity of the two satellites. e a1 and e a2 This represents the eccentricity of satellites M1 and S2; similarly, the eccentricity e of satellites M3 and S4 can be obtained. a3 and e a4 ;

[0041] The task requirements specify a baseline for multiple stars arranged side-by-side, achieving a maximum length B. z The corresponding u c The value u0 is used to obtain the latitude argument ω of satellite M1. a1 =u0, the latitudinal argument of satellite S2 satisfies ω a2 =ω a1 +180°;

[0042] Based on the field-of-view constraints of the measurement system, the baseline tilt difference Δα between the two pairs of satellites, MS1 and MS2, is constrained to be Δα ≥ 2θ, where θ is given by the mission requirements. Therefore, Δω ≥ 2θ. Since a smaller baseline angle Δα results in better observation, Δω = 2θ. a3 =ω a1 +2θ,ω a4 =ω a3 -180°; via condition ua - u c = 0, the initial argument of perigee M of each satellite is obtained a = u a - ω a ; thus the initial orbit parameters of the formation satellites are obtained.

[0043] If there is a common view blockage, the orbit parameters of one group of formation satellites are adjusted in orbit by using the constraint relationship of the baseline vector with the field of view requirement so that any two groups of baselines satisfy the constraint relationship, including: real-time measurement of the inter-satellite baselines MS1 and MS2 is realized by GNSS navigation, the difference Δα of the baseline directions of MS1 and MS2 is obtained, the constraint relationship criterion of the baseline vector with the field of view requirement of the baseline measurement system is used, and the argument of perigee ω a1 , ω a2 , ω a3 , ω a4 of the four satellites are specifically adjusted, so that the on-board autonomous avoidance of the common view blockage of the formation system is realized.

[0044] The argument of perigee ω a1 , ω a2 , ω a3 , ω a4 of the four satellites are specifically adjusted, including: taking the argument of latitude ω a1 of the satellite M1 as a reference, the argument of latitude of the satellite S2 satisfies ω a2 = ω a1 + 180°; by using the relationship Δω = 2θ, ω a3 = ω a1 + 2θ, ω a4 = ω a3 - 180°.

[0045] Compared with the prior art, the present application has the following advantages:

[0046] (1) The present application establishes a mathematical relationship model of the inter-satellite baseline and the orbit parameters of the distributed formation satellite system, and provides a theoretical method for the orbit parameter design of the formation system for a three-dimensional imaging observation task.

[0047] (2) The present application establishes a constraint relationship of the inter-satellite baseline vector with the field of view requirement of the baseline measurement system, and is applied to the theoretical design of the orbit parameters of the distributed formation satellite and the real-time orbit adjustment in orbit.

[0048] (3) In actual in-orbit operation, the present application judges whether there is a common view blockage by using the orbit parameters solved in real time by GNSS information, so as to complete the adjustment of the orbit parameters and meet the requirement of the real-time measurement of the inter-satellite baseline.

[0049] (4) The method constructed by the application can solve the baseline design problem of the distributed multi-satellite system formation configuration, and solve the baseline co-visibility occlusion problem in real time, and the whole process of on-orbit operation can be autonomously planned and executed on the satellite, which is high in efficiency and speed, helps flexible response to tasks, and has practical engineering significance. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a distributed side-by-side multi-satellite formation system and configuration schematic diagram;

[0051] Figure 2 It is a baseline measurement system field of view and inter-satellite baseline schematic diagram;

[0052] Figure 3 It is a satellite formation configuration diagram;

[0053] Figure 4 It is a satellite baseline distribution. DETAILED DESCRIPTION

[0054] The application will be further explained and described below in combination with the drawings of the specification and the specific embodiments.

[0055] As shown in the drawings, Figure 1 In the design of the formation satellite orbit parameters, the required formation multi-satellite coplanar flight and the virtual center O are symmetrically distributed, and each pair of satellites is defined as a group (M1, S2) (M3, S4) to fly forward together, and the space connecting line of the main star and the auxiliary star is called the space baseline MS1, MS2. When the baseline angle Δα is less than the field of view angle, the remote baseline between the two stars cannot be measured due to the field of view occlusion. In the design of the formation system, it is necessary to avoid the case that the baseline angle Δα is less than the field of view angle, and in the on-orbit operation of the formation system, it is necessary to adjust the orbit parameters on-orbit to make the baseline angle Δα less than the field of view angle. Through the design of the formation satellite orbit and the adjustment of the orbit parameters, the multi-satellite co-visibility occlusion problem of the formation satellite system can be avoided.

[0056] A side-by-side multi-satellite formation design capable of real-time high-precision relative measurement includes the following steps:

[0057] Step 1, based on the theory of orbit kinematics, a mathematical model of the relative motion of the formation multi-satellite is established, and a mathematical model of the inter-satellite baseline is established by simplifying the relative motion, and a mathematical expression of the relationship between the baseline vector and the six elements of the orbit is obtained, and a direct correspondence between the baseline requirements of the formation system and the orbit parameters is established.

[0058] Further, the specific steps of step 1 are:

[0059] Step 1.1: Establish the coordinates of the slave star relative to the master star in the RTN coordinate system, and simplify them to obtain the expression for the relative motion of the slave star relative to the master star:

[0060] Δr R =a a -a c +a c [-(e a cosω a -e c cosω c cosu c -(e a sinω a -e c sinω c )sinu c (1)

[0061]

[0062] Δr N =a c [-(Ω a -Ω c )sini c cosu c +(i a -i c )sinu c (3)

[0063] Where u c It is the mean latitude argument of the primary star, u c =ω c +M c M c It is the angle of approach, Ω c (h c ) and r c These are the right ascension of the ascending node and the geocentric distance of the primary star, i c It is the inclination of the primary star, e c It is the eccentricity of the primary star, a c It is the semi-major axis of the primary star. a e a u a M a Ω a i a and r a The physical meaning of the orbital variables of a star is the same as described above.

[0064] Step 1.2: Simplify the formula in Step 1.1, let a a -a c =0, u a -u c= 0, with virtual star O as the primary star, the primary star is a circular orbit, e c = 0, simplifying the above formula, we get,

[0065] Δr R = -a c e a cos(u c - ω a ) (4)

[0066] Δr T = 2a c e a sin(u c - ω a ) (5)

[0067]

[0068] where, the remaining variables are the same as the above formula.

[0069] As Figure 2 shown, according to the baseline requirements between the stars of the formation system, the normal N direction baseline component is not considered here, each group of baseline satellites at both ends and the virtual star O are on the same straight line, and the distance between the two satellites and the virtual star O is equal, at this time the eccentricity of the two satellites needs to be equal, i.e. e a1 = e a2 , at the same time the two satellites' argument of perigee is 180°, i.e. ω a1 = ω a2 -180°.

[0070] Step 1.3, according to the formula in step 1.2, the expression of the baseline between the stars in the R-T plane is 2 times the relative motion of a single satellite, i.e.

[0071] The radial R direction baseline length B z :

[0072] B z = 2Δr R = -2a c e a1 cos(u c - ω a1 ), (7)

[0073] The flight direction T direction baseline length B x :

[0074] B x = 2Δr T = 4a c e a1 sin(u c - ω a1 ) (8)

[0075] Baseline tilt angle α:

[0076]

[0077] α=arctan(-0.5cot(u c -ω a1 (10)

[0078] Step 2, as follows Figure 1 and Figure 2 As shown, the constraint relationship between the field of view requirements of the baseline measurement system and the baseline vector is established. With virtual star O as the center, the two satellites of each baseline are located on both sides of the center O. Taking the figure as an example, M1 and S2 are one group, and M3 and S4 are another group. The expression for the baseline inclination difference between the two groups of satellites is as follows:

[0079] Δα=arctan(-0.5cot(u c -ω a3 ))-arctan(-0.5cot(u c -ω a1 (11)

[0080] Based on the above formula, the range of variation for Δα is: Δω=ω a3 -ω a1 This constraint relationship is applied as the basis for the theoretical design of orbital parameters and real-time on-orbit orbit adjustment.

[0081] Δα≥θ (12)

[0082] That is,

[0083] Δω=ω a3 -ω a1 ≥2θ (13)

[0084] Step 3, the formation configuration design step, is based on the formulas and constraints derived in Steps 1 and 2, and the formation configuration can be designed according to specific baseline constraints.

[0085] Furthermore, the specific steps of step 3 are as follows:

[0086] Step 3.1, based on the remote sensing satellite regression characteristics and observation performance requirements, the semi-major axis a c The size is given through mission calculations, as are the orbital inclination and right ascension of the ascending node; for any pair of satellites forming the baseline, the maximum baseline length B in the radial R direction is given according to mission requirements. z That is, to obtain the eccentricity of the two satellites. e a1 and e a2denotes eccentricity of satellite M1, satellite S2; similarly, eccentricity e of satellite M3, satellite S4 can be obtained a3 and e a4 ;

[0087] Step 3.2, the baseline of the side-by-side multiple satellites is given the maximum length B by task requirement z corresponding u c value u0, and then the latitude amplitude ω of satellite M1 is obtained a1 = u0, the latitude amplitude ω of satellite S2 satisfies ω a2 = ω a1 + 180°;

[0088] Step 3.3, according to the field of view constraint relationship of the measurement system, the baseline inclination angle difference Δα of the baselines MS1 and MS2 formed by the two pairs of satellites is constrained, that is, Δα ≥ θ, θ is given by the task requirement, and Δω ≥ 2θ can be determined, since the smaller the included angle Δα of the double baseline is, the better the observation effect is, then Δω = 2θ, ω a3 = ω a1 + 2θ, ω a4 = ω a3 - 180°; by the condition u a - u c = 0, the initial perigee angle M of each satellite is obtained a = u a - ω a . Thus, the initial orbit parameters of the formation satellites are obtained.

[0089] Step 4, as Figure 1 in the specification, real-time measurement of the inter-satellite baselines MS1 and MS2 is realized by GNSS navigation, the difference Δα of the baseline directions of MS1 and MS2 is obtained, and the perigee amplitudes ω a1 , ω a2 , ω a3 , ω a4 of the four stars are specifically adjusted by using the criterion of step 2. The on-board autonomous avoidance of the multi-satellite common view occlusion of the formation system is realized.

[0090] The effects of the present application will be briefly introduced and described in combination with specific examples.

[0091] The task requirement designs a four-satellite formation with a semi-major axis of 6873.68km, and the four satellites are approximately uniformly distributed side by side, wherein the maximum value of the long baseline is 1km, the maximum value of the short baseline is 0.33km, and the latitude amplitude u c The baseline length reaches the maximum near the equator, and the included angle of the baseline directions of the two groups of inter-satellite baselines MS1 and MS2 needs to be not less than 3°, and the overall formation parameters can be obtained by the following process:

[0092] 1, eccentricity of outer circle satellites M1, S2 Eccentricity of inner circle stars M3 and S4

[0093] 2. The baseline reaches its maximum near the equator, i.e., u0 = 0, ω a1 =0, and ω a2 =ω a1 -180° = 180°.

[0094] 3. The angle between the baseline directions of the two inter-satellite baselines MS1 and MS2 is Δα ≥ 3°, θ = 3°, Δω = 2θ = 6°, ω a3 =ω a1 -2θ=6°,ω a4 =ω a3 +180° = 186°. When the baseline design in the normal N direction is not considered, the right ascension Ω of the ascending node of all slave stars and the virtual primary star can be kept consistent. The following formation design parameters can then be obtained:

[0095]

[0096] Using simulation software to simulate the above-mentioned formation design, the following results can be obtained: Figure 3 The satellite formation configuration diagram shown illustrates the spatial baseline distribution under this design configuration. Figure 4 As shown.

[0097] 4. When the satellite formation is in orbit, if the inter-satellite baselines MS1 and MS2 measured by GNSS navigation are obstructed, the perigee argument ω of the four satellites will be adjusted. a1 ω a2 ω a3 ω a4 This satisfies the on-board autonomous mission avoidance requirement when the formation system has common-view blockage in orbit.

[0098] The design method for the side-by-side multi-satellite distributed formation proposed in this invention can solve the problem of common line-of-sight occlusion between multiple satellites from both theoretical design and actual on-orbit operation, and can achieve high-precision measurement of inter-satellite baselines at any time.

[0099] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A side-by-side multi-satellite formation method capable of real-time high-precision relative measurement, characterized in that, The application relates to a method for realizing real-time high-precision relative measurement of a multi-satellite formation. The method comprises the following steps: A mathematical model of relative motion of the multi-satellite formation is established based on orbit kinematics theory, an intersatellite baseline mathematical model is established through relative motion deduction and simplification, a mathematical expression of the relationship between a baseline vector and six orbit parameters is obtained, and a direct correspondence between baseline requirements of the formation system and the orbit parameters is established; A constraint relationship of a baseline measurement system field of view requirement to the baseline vector is established; When the formation configuration and the orbit are designed, two satellites in the multi-satellite distributed formation are taken as a group, the relative orbit parameters of any two satellites in the distributed formation are obtained according to the baseline requirements and the correspondence, the constraint relationship of the field of view requirement to the baseline vector is used to correct the relative orbit parameters of the two groups of satellites, an initial orbit parameter of a satellite is designed as a master star, and then initial orbit parameters of the rest of the satellites in the formation are obtained according to the above relative orbit parameters; 2. The side-by-side multi-satellite formation method of claim 1, wherein, During on-orbit operation, orbit parameters are solved in real time through GNSS, a spatial baseline formed by any two satellites in the distributed formation is obtained according to the mathematical expression, the constraint relationship of the field of view requirement to the baseline vector is used to judge whether multiple groups of baselines formed by multiple satellites exist in common view shielding, if the common view shielding exists, the orbit parameters of one group of formation satellites are adjusted on orbit according to the constraint relationship of the field of view requirement to the baseline vector so that any two groups of baselines satisfy the constraint relationship, and thus real-time high-precision relative measurement of the side-by-side multi-satellite formation at any moment is realized. The method comprises the following steps: Δr R = a a - a c + a c [- (e a cos ω a - e c cos ω c ) cos u c - (e a sin ω a - e c sin ω c ) sin u c ] Δr N = a c [-(Ω a -Ω c )sini c cosu c +(i a -i c )sinu c ] wherein u c is the amplitude of the latitude of the primary star, u c = ω c + M c , M c is the mean anomaly, Ω c and r c are the right ascension of the ascending node and the geocentric distance of the primary star, i c is the inclination of the primary star, e c is the eccentricity of the primary star, a c is the semi-major axis of the primary star; a a , e a , u a , M a , Ω a , i a and r a are the orbital variables of the satellite, the physical meanings of which correspond to the above-mentioned primary star; Let a a - a c = 0, u a - u c = 0, with the virtual star O as the primary star, the primary star as a circular orbit, e c = 0, the relative motion expression of the secondary star relative to the primary star is simplified, and the following equation is obtained Δr R = -a c e a cos(u c -ω a ) Δr T = 2a c e a sin(u c -ω a ) wherein According to the inter-satellite baseline requirement of the formation system, the baseline component in the normal direction N is not considered, two satellites M1 and S2 in each group of baseline are at the two ends of the same straight line with the virtual star O, and the distance between the two satellites and the virtual star O is equal, at this time the eccentricity of the two satellites is equal, i.e. e a1 = e a2 , and the argument of perigee of the two satellites is 180°, i.e. ω a1 = ω a2 -180°; wherein the subscripts 1 and 2 represent the satellites M1 and S2 in the formation respectively. An RTN coordinate system of a spacecraft master star is established, and then a relative motion expression of a slave star relative to the master star in the RTN coordinate system is obtained; 3. The side-by-side multi-satellite formation method of claim 2, wherein, An R-T plane component expression of an intersatellite baseline in the RTN coordinate system is obtained, and a baseline length and a baseline inclination are obtained. Radial R direction baseline length B z : B z = 2Δr R = -2a c e a1 cos(u c - ω a1 ), Flight direction T Baseline length B x : B x = 2Δr T = 4a c e a1 sin(u c -ω a1 ) The baseline length and the baseline inclination expressions are respectively as follows: a = arctan(-0.5 cot(u c - ω a1 )).

4. The side-by-side multi-satellite formation method of claim 2, wherein, The baseline inclination alpha is as follows:

5. The side-by-side multi-satellite formation method of claim 4, wherein, The RTN coordinate system of the spacecraft master star is established, and the relative motion coordinate system of the formation flight is defined as the coordinate system, the coordinate system origin is the master star spacecraft, the R direction is a direction of the earth center pointing to the master star, the T direction is a motion direction of the master star, and the N direction is a normal direction of an orbit plane determined by a right-hand system. The constraint relationship of the baseline measurement system field of view requirement to the baseline vector is established, the virtual star O is taken as a center, the formation satellites M1, M3 and M3 are located on the same side of the center O, the formation satellites S2, S4 and S4 are located on the other side of the center O, the satellites M1 and S2 form a spatial baseline MS1, the satellites M3 and S4 form a spatial baseline MS2, and so on; and the baseline inclination difference expression of the baseline MS1 and the baseline MS2 is as follows: Δα = arctan(-0.5 cot(u c - ω a3 )) - arctan(-0.5 cot(u c - ω a1 )) According to the above rule, the range of the baseline inclination difference Δα is where Δω = ω a3 -ω a1 The subscripts 1 and 3 represent the satellite M1 and the satellite M3, respectively. Delta alpha is greater than or equal to theta Wherein, theta represents a maximum field of view angle of the baseline measurement system; Therefore, Δω = ω a3 - ω a1 ≥ 2θ; That is, the perigee amplitude difference requirement of the satellite M3 and the satellite M1 is greater than 2 times the field of view angle.

6. The side-by-side multi-satellite formation method of claim 5, wherein, The relative orbit parameters of any two satellites in the distributed formation satellite are obtained according to the baseline requirements by using the correspondence, and the relative orbit parameters of the two groups of satellites are corrected by using the constraint relationship of the baseline vector according to the field of view requirements, an orbit initial parameter of a satellite is designed as a main star, and thus the initial orbit parameters of the remaining several satellites in the formation are obtained according to the relative orbit parameters, including: Based on the regression characteristics of remote sensing satellites and the requirements for observation efficiency, the semi-major axis a c The size is given through mission calculations, as are the orbital inclination and right ascension of the ascending node; for any pair of satellites forming the baseline, the maximum baseline length B in the radial R direction is given according to mission requirements. z That is, to obtain the eccentricity of the two satellites. e a1 and e a2 This represents the eccentricity of satellites M1 and S2; similarly, the eccentricity e of satellites M3 and S4 can be obtained. a3 and e a4 ; The baseline of side-by-side multiple stars is given by the task requirement to reach the maximum length B z The value u0 of the corresponding u c , and then the argument of perigee ω of the satellite M1 α1 = u0, the argument of perigee of the satellite S2 satisfies ω a2 = ω a1 + 180°; According to the field of view constraint relationship of the measurement system, the baseline inclination angle difference Δα of the baselines MS1 and MS2 formed by the two pairs of satellites is constrained, that is, Δα≥θ, θ is given by the task requirement, which can determine Δω≥2θ, since the smaller the double baseline included angle Δα is, the better the observation effect is, then Δω=2θ, ω a3 =ω a1 +2θ, ω a4 =ω a3 -180°; by the condition u a -u c =0, the initial mean anomaly M a =u a -ω a of each satellite is obtained; thus, the initial orbit parameters of the formation satellites are obtained.

7. The side-by-side multi-satellite formation method of claim 5, wherein, If there is a common view block, the constraint relationship of the baseline vector by the field of view requirement is used to adjust the formation satellite orbit parameters of one group on orbit so that any two groups of baselines satisfy the constraint relationship, including: realizing real-time measurement of inter-satellite baselines MS1 and MS2 through GNSS navigation, obtaining the difference Δα of the baseline directions of MS1 and MS2, and specifically adjusting the four stars' argument of perigee ω a1 、ω a2 、ω a3 、ω a4 , so as to realize on-orbit autonomous avoidance of common view block of the formation system multi-satellite.

8. The side-by-side multi-satellite formation method of claim 7, wherein, The specific adjustment of the argument of perigee ω a1 of the four satellites a2 , ω a3 , ω a4 includes: taking the argument of perigee ω a1 of satellite M1 as a reference, the argument of perigee of satellite S2 satisfies ω a2 = ω a1 + 180°; using the relationship Δω = 2θ, adjusting ω a3 = ω a1 + 2θ, ω a4 = ω a3 - 180°.

Images