Low-to-low multi-satellite observation task planning and designing method

Abstract

The invention discloses a low-to-low multi-satellite observation task planning and designing method, and the method comprises the following specific steps: 1) determining target constellation orbit deployment related parameters in a low-to-low multi-satellite observation task system, the target constellation orbit deployment related parameters specifically comprising a target constellation orbit height H < Tar >, a target constellation orbit inclination angle i < Tar >, a target constellation orbit height i < Tar >, a target constellation orbit inclination angle i < Tar > and a target constellation orbit inclination angle i < Tar >; the target constellation orbital plane number PTar and the target constellation same orbital plane satellite number NSar are calculated; 2) determining the orbit height of the monitoring satellite by referring to the target constellation orbit height distribution characteristics; 3) determining the number of orbital planes needing to be deployed by the monitoring satellite system and the number of monitoring satellites on each plane by combining target constellation orbit deployment related parameters and task time requirements; 4) analyzing task requirements according to given specific tasks, and proposing a task planning strategy of a single satellite to multiple satellites; and 5) completing multi-target simulation analysis of multiple satellites, and giving a low-to-low multi-satellite observation task result. According to the method, two technologies of maneuvering orbital transfer and natural intersection are combined, the problem of narrow imaging window of a single-to-single target different-plane grazing autonomous task planning algorithm in actual engineering use is successfully solved, and low-consumption and high-efficiency multi-target observation is finally realized.

Description

Technical Field

[0001] This patent relates to the technical field of multi-satellite observation mission planning in orbital design, specifically to a low-to-low multi-satellite observation mission planning and design method, involving theoretical analysis, simulation techniques, steps, rationality and other related technologies of constellation configuration design. Background Art

[0002] Low-orbit space is the focus of global aerospace development. With the development of low-orbit satellite constellations, which have obvious advantages in terms of launch costs and global coverage, and have the characteristics of strong anti-destruction, low transmission delay and low power link, low-orbit broadband satellite network systems characterized by low orbit, giant and constellation are booming worldwide, and the mass deployment of low-orbit constellations has entered a peak period. Since large low-orbit constellations can provide all-dimensional, all-weather and all-day reconnaissance and surveillance capabilities with high revisit rate and resolution, they can achieve global coverage, large bandwidth, high-speed military communication services, and have strong anti-destruction capabilities. Therefore, the vigorous development of low-orbit giant constellations will have a significant impact on military security and space resources. In order to obtain and maintain space advantages in a timely manner, it is necessary to use multi-satellite observation mission planning methods to improve the monitoring, early warning and tracking capabilities of single satellites for space targets, and respond to the tasks that these satellites may perform, such as on-orbit mobile reconnaissance interference and ground strikes, at the lowest cost.

[0003] Multi-satellite observation mission planning is a key technology for efficient observation. In the traditional design of the most fuel-efficient multi-target observation mission, multi-target natural rendezvous sequence planning is widely used. However, this method cannot realize orbit change observation of designated key targets, which greatly reduces the effectiveness and flexibility of the mission. Summary of the invention

[0004] In order to realize the most fuel-efficient observation of designated key targets while taking into account the completion of other targets in the target set, the present invention provides a low-to-low multi-satellite observation mission planning and design method, which improves the mission planning of a single satellite for a single target to the mission planning of a single satellite for multiple targets, approaches the key target at a close distance through maneuvering and changing orbits, and after the observation of the key target is completed, other targets in the target group can be observed as much as possible through natural intersection. Based on the single-to-multi-target mission planning strategy analysis and design, the low-orbit monitoring constellation system observes the target constellation, and completes the low-to-low multi-satellite observation mission planning. This method combines the two technologies of maneuvering and changing orbits and natural intersection, successfully solving the problem of narrow imaging window in the actual engineering use of the single-to-single target non-planar flyby autonomous mission planning algorithm, and ultimately achieves low-cost and efficient multi-target observation.

[0005] The technical solution of the present invention is: a low-to-low multi-satellite observation mission planning and design method, the specific steps are as follows:

[0006] Step 1) Determine the orbital deployment parameters of the target constellation in the low-to-low multi-satellite observation mission system. The orbital deployment parameters of the target constellation specifically include: the orbital height H of the target constellation Tar , the target constellation orbit inclination i Tar , the number of orbital planes of the target constellation P Tar The number of satellites N in the same orbital plane as the target constellation Tar value;

[0007] Step 2) determining the orbital altitude of the monitoring satellite with reference to the orbital altitude distribution characteristics of the target constellation;

[0008] Step 3) Determine the number of orbital planes that the monitoring satellite system needs to deploy and the number of monitoring satellites per plane in combination with the target constellation orbit deployment related parameters and mission time requirements;

[0009] Step 4) Analyze the mission requirements and propose a single satellite to multiple satellite mission planning strategy based on the given specific mission;

[0010] Step 5) Complete the simulation analysis of multiple satellites on multiple targets and give the results of the low-to-low multi-satellite observation mission.

[0011] Further, the step 2) is specifically as follows:

[0012] Combined with the orbital deployment parameters of the target constellation, according to the theory of flyby rendezvous and the characteristics of space orbit, the premise of whether the monitoring satellite can conduct a limited-time flyby rendezvous with the target satellite includes two items:

[0013] (1) Does the relative angular velocity meet the following conditions:

[0014] If the cross-plane rendezvous time is required to be less than K days, then in, To monitor the orbital angular velocity difference between the satellite and the target star;

[0015] (2) Whether the radial difference at the intersection point meets the fuel constraint:

[0016] The greater the relative orbital angular velocity, the shorter the time required for out-of-plane rendezvous; the smaller the difference in radial vectors at the intersection point, the less fuel required;

[0017] When the orbital eccentricity of the target constellation is e Tar Equal to 0, the target constellation orbit height is H Tar , requiring the time of cross-plane rendezvous to be less than K days, then The monitoring satellite orbit height H Sat Need to meet:

[0018]

[0019] Where a is the semi-major axis of the satellite orbit, as and a t are the semi-major axes of the monitoring satellite and target satellite orbits respectively; n is the angular velocity of the satellite orbit, To monitor the angular velocity of the satellite, is the angular velocity of the target star; the radius of the earth R e =6378.137km, Earth's gravitational parameter μ = 398600.4415km3 / s2;

[0020] According to formula (3), the orbital height H of the monitoring satellite that meets the specified mission duration is calculated sat .

[0021] Further, the step 3) is specifically as follows:

[0022] Considering that a target constellation orbital plane needs to perform at least one close-range observation mission, the total velocity increment ΔV is required. st for:

[0023]

[0024] Among them, T s To monitor the satellite orbit period, Δr j and Δv j is the rendezvous radius difference and required velocity increment of a single monitoring satellite to a single target star on the jth plane;

[0025] When the velocity increment provided by the fuel carried by the monitoring satellite is ΔV m / s, at least the number of monitoring satellites required to be deployed is Date Sat for:

[0026] Date Sat =ceil(ΔV st / ΔV) (5)

[0027] In order to effectively reduce fuel consumption and launch costs, Date Sat The monitoring satellites are deployed equally at 360° of the ascending node longitude; therefore, the monitoring satellite constellation consists of one satellite per orbital plane. Sat The orbital surface is composed of

[0028] Furthermore, the step 4) is as follows: It is known that the orbital parameters of a single monitoring satellite are E s , the target constellation orbit parameter set is [E T0 ,E T1 ,E T2 ,...E TN], where the 0th target constellation is the key target; the goal of autonomous mission planning is to design an orbit change strategy for the 0th target to perform close-range rendezvous imaging, and after the imaging of the key target is completed, natural rendezvous imaging of other targets in the target set is performed as much as possible; the specific planning process is as follows: a) Determine the rendezvous orbit parameter set that satisfies the close-range observation of the key target based on the payload observation constraint; b) Determine the control strategy that meets the rendezvous parameter requirements based on the Lambert principle and measurement and control resource constraints; c) Determine the post-control orbit based on the control strategy and calculate the natural rendezvous opportunities of the remaining target stars on the same orbital plane; d) Optimize and select the final control strategy with "shortest rendezvous distance with the key target" and "more natural rendezvous opportunities on the post-control orbit" as indicators; finally, the control strategy with the best indicators is used as the mission planning strategy for a single satellite to multiple satellites.

[0029] Further, the step 5) is specifically as follows:

[0030] Clearly define the key targets for each monitoring satellite's orbit change observation and the natural flyby observation order of other targets in the same orbital plane; uniformly deploy N satellites on each orbital plane of the target constellation. Tar target stars, then this N Tar The phase difference between the target stars is (360 / N Tar )°, when the monitoring satellite runs m circles after the out-of-plane flyby, there is a phase difference of about m*(360 / N Tar )°, m=1,2,3…N, m is a positive integer, then it can intersect with a satellite on the orbital plane; therefore, a monitoring satellite completes all observations of the remaining target stars on the same orbital plane after a non-plane flyby, and the fastest time required is Time extra :

[0031]

[0032] Among them, T sci and n extrai are the orbital period and angular velocity of the monitoring satellite in the i-th circle after the out-of-plane flyby; f is the phase difference between two satellites in the coplanar uniformly distributed target constellation; ΔAnglei is the phase difference between the monitoring satellite and the initial key target at the i-th circle to the intersection point after the monitoring satellite in the out-of-plane flyby; Time extra To monitor the time required to complete the natural rendezvous with all remaining targets after the satellite flyby is completed;

[0033] When the monitoring satellite completes the key target orbit change observation, the time required is Time Ctrl , then the shortest time required for the monitoring constellation to complete the observation of the target constellation is:

[0034]

[0035] According to formula (7), the time required for a single monitoring satellite to complete an observation of a target orbital plane is (Time Ctrl +Time allextra ), so each monitoring satellite is responsible for completing (P Tar / Data Sat ) target orbital plane observations, the time required for the monitoring satellite constellation to complete all target observations is the shortest.

[0036] The beneficial effects of the present invention are as follows: based on the orbital deployment of the target constellation, a theoretical analysis is given to clarify the orbital altitude of the monitoring satellite; the number of monitoring satellite orbital planes and the number of monitoring satellites per plane are determined according to constraints such as the orbital characteristics of the target constellation, fuel consumption and mission duration; in combination with actual mission requirements, a single-satellite-to-multiple-satellite mission planning strategy is proposed and a multi-satellite-to-multi-target simulation analysis is performed, and the low-to-low multi-satellite observation mission results are given according to the simulation analysis results.

[0037] This method improves the mission planning of a single satellite for a single target to a single satellite for multiple targets. It approaches the key target at a close distance through maneuvering and changing orbits, and after the observation of the key target is completed, it can observe other targets in the target group as much as possible through natural rendezvous. Based on the single-to-multi-target mission planning strategy analysis and design, the low-orbit surveillance constellation system observes the target constellation and completes the low-to-low multi-satellite observation mission planning. This method combines the two technologies of maneuvering and changing orbits and natural rendezvous, successfully solving the problem of narrow imaging window in the actual engineering use of the single-to-single target out-of-plane flyby autonomous mission planning algorithm, and finally realizes low-cost and efficient multi-target observation.

[0038] The present invention solves the problem of narrow imaging window of traditional single satellite single target flyby mission by proposing a low-to-low multi-satellite observation mission planning and design method. When the observation opportunity is missed, the monitoring satellite can continue to perform natural rendezvous observation missions on other targets, effectively improving the observation efficiency of monitoring satellite orbit change. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a process flow of a low-to-low multi-satellite observation mission planning and design method provided by the present invention;

[0040] Figure 2 A simulation result diagram of the change of the intersection point radius vector difference with the ascending node right ascension difference provided by the present invention;

[0041] Figure 3 The present invention provides a rendezvous observation opportunity between a single surveillance satellite and an orbital plane in the Starlink shell 1. DETAILED DESCRIPTION

[0042] In order to illustrate the above invention, a low-to-low multi-satellite observation mission planning and design method of this patent adopts the following technical solution:

[0043] 1) Clarify the orbital deployment parameters of the target constellation in the low-to-low multi-satellite observation mission system. The orbital deployment parameters of the target constellation specifically include: the orbital height H of the target constellation; Tar , the target constellation orbit inclination i Tar , the number of orbital planes of the target constellation P Tar The number of satellites N in the same orbital plane as the target constellation Tar value;

[0044] 2) Determine the orbital altitude of the monitoring satellite based on the orbital altitude distribution characteristics of the target constellation;

[0045] 3) Determine the number of orbital planes that the monitoring satellite system needs to deploy and the number of monitoring satellites per plane based on the orbital deployment parameters of the target constellation and the mission time requirements;

[0046] 4) Based on the given specific mission, analyze the mission requirements and propose a mission planning strategy for a single satellite to multiple satellites;

[0047] 5) Complete the simulation analysis of multiple satellites on multiple targets and provide the results of low-to-low multi-satellite observation mission.

[0048] Furthermore, the step 2) specifically includes: combining the orbital deployment parameters of the target constellation, according to the theory of flyby rendezvous and the characteristics of space orbit operation, the premise of whether the monitoring satellite can conduct a limited time flyby rendezvous with the target satellite includes two conditions: 1. whether the relative angular velocity meets the conditions, and 2. whether the intersection point radial difference meets the fuel constraint. These two conditions are theoretical analyses under an ideal space environment. When actually designing the flyby maneuver strategy, the measurement and control resource constraints, high-precision orbit extrapolation model, illumination constraints and other conditions will be fully considered.

[0049] (1) Relationship between relative angular velocity and time required for cross-plane rendezvous

[0050] When the latitude angle values ​​of the monitoring satellite and the target satellite are u s0 and u t0 , then the latitude angle difference between the monitoring satellite and the target satellite can be expressed as Δu st =u t0 -u s0 ; The angular velocities of the monitoring satellite and the target satellite are and The orbital angular velocity difference between the monitoring satellite and the target satellite is Then the time required for the monitoring satellite to intersect the target star in the satellite orbit is:

[0051]

[0052] Taking the out-of-plane rendezvous time of less than 1 day as an example, the requirements for calculating the relative angular velocity are as follows.

[0053] if but If Δu st =u t0 -u s0 <0, then for any orbit, the maximum latitude argument difference is |Δu st |=360, If Δu st =u t0 -u s0 > 0, then for any orbit, the maximum latitude argument difference is Δu st =360,

[0054] if but If Δu st =u t0 -u s0 <0, then for any orbit, the maximum latitude argument difference is Δu st =-360, the minimum is 0, If Δu st =u t0 -u s0 > 0, then for any orbit, the maximum latitude argument difference is Δu st =360,

[0055] In summary, if the cross-plane rendezvous time is required to be less than 1 day, then Similarly, if the time required for the cross-plane rendezvous is less than K days, then

[0056] (2) Relationship between the radial difference at the intersection point and the required fuel

[0057] When designing the maneuvering strategy for out-of-plane flying, the minimum fuel consumption that meets the mission load constraints is generally considered, that is, the intersection points with smaller radius vector differences are considered as the points for out-of-plane flying.

[0058] Assume that the radial differences between the monitoring satellite and the target satellite at the two intersection points are Δr A and Δr B , and Δr A <Δr B , if point A satisfies the mission load constraint, then point A is selected as the point of the out-of-plane flyby, and the difference in the star arrow radius with the target during the flyby is 0, and the required velocity increment is calculated as follows.

[0059]

[0060] Among them, a S To monitor the semi-major axis of the satellite orbit, the unit is km; Earth gravity parameter μ = 398600.4415 km 3 / s 2 ; T s is the satellite orbit period, in seconds; Δr A is the radial difference, in m, then the transfer Δr A The radial difference requires a velocity increment of Δv A .

[0061] According to formula (2), the greater the relative orbital angular velocity, the shorter the time required for out-of-plane rendezvous; the smaller the radius vector difference at the intersection point, the less fuel required.

[0062] When the target star orbit eccentricity e Tar is equal to 0, and the target star orbit height is H Tar , requiring the time of cross-plane rendezvous to be less than K days, then The monitoring satellite orbit height H Sat Need to meet:

[0063]

[0064] Where a represents the semi-major axis of the satellite orbit, a s and a t are the semi-major axes of the monitoring satellite and target satellite orbits respectively; n is the angular velocity of the satellite orbit, To monitor the angular velocity of the satellite, is the angular velocity of the target star. The radius of the Earth is R e =6378.137km, Earth's gravitational parameter μ = 398600.4415km 3 / s 2 According to formula (3), the orbital height H of the monitoring satellite that meets the specified mission duration is calculated. sat .

[0065] Further, the step 3) specifically includes: the orbital inclination of the target constellation i is known Tar , the number of orbital planes of the target constellation P Tar The number of satellites N in the same orbital plane as the target constellation Tar The right ascension of each orbital node is Ω Tar =360 / P Tar . When the semi-major axis, eccentricity and orbital inclination of the monitoring satellite are determined, the smaller the right ascension difference between the ascending node of the monitoring satellite and the target star, the smaller the vector radius difference of the intersection line, that is, the smaller the orbital plane angle, the smaller the vector radius difference of the intersection line, and the lower the fuel consumption. Therefore, the more orbital planes the monitoring satellite has, the lower the fuel consumption of the out-of-plane flyby. Assuming that the maximum vector radius difference between the monitoring satellite and the target star is Δr max , the minimum radial difference is Δrmin Considering that a target constellation orbital plane must perform at least one close-range observation mission, a total velocity increment ΔV is required. st for:

[0066]

[0067] Among them, T s is the satellite orbit period, Δr j and Δv j It is the rendezvous radius difference and required velocity increment of a single monitoring satellite for a single target star on the jth plane.

[0068] When the velocity increment provided by the fuel carried by the monitoring satellite is ΔVm / s, at least the number of monitoring satellites required to be deployed is Date Sat for:

[0069] Date Sat =ceil(ΔV st / ΔV) (5)

[0070] In order to effectively reduce fuel consumption and launch costs, Date Sat The monitoring satellites are deployed equally at 360° of the ascending node longitude. Therefore, the monitoring satellite constellation consists of a Date satellite in each orbital plane. Sat The orbital surface is composed of

[0071] Furthermore, the step 4) specifically includes: the orbital parameters of a single monitoring satellite are known to be E s , the target constellation orbit parameter set is [E T0 ,E T1 ,E T2 ,...E TN ], where the 0th target constellation is the key target. The goal of autonomous mission planning is to design an orbit change strategy for the 0th target to perform close-range rendezvous imaging, and after the imaging of the key target is completed, natural rendezvous imaging of other targets in the target set is performed as much as possible. The specific planning process is as follows: a) Determine the rendezvous orbit parameter set that satisfies the close-range observation of the key target based on the payload observation constraints; b) Determine the control strategy that meets the rendezvous parameter requirements based on the Lambert principle and measurement and control resource constraints; c) Determine the post-control orbit based on the control strategy and calculate the natural rendezvous opportunities of the remaining target stars on the same orbital plane; d) Optimize and select the final control strategy based on the indicators of "shortest rendezvous distance with the key target" and "more natural rendezvous opportunities on the post-control orbit". Finally, the control strategy with the best indicators is used as the mission planning strategy for a single satellite to multiple satellites.

[0072] Furthermore, the step 5) specifically includes: clarifying the key targets for each monitoring satellite to observe during orbit change and the natural flyby observation sequence of other targets in the same orbital plane. Tar target stars, then this N Tar The phase difference between the target stars is (360 / N Tar )°, when the monitoring satellite runs m circles after the out-of-plane flyby, there is a phase difference of about m*(360 / N Tar )°, m=1,2,3…N (m is a positive integer), then it can intersect with a satellite on the orbital plane. Therefore, a monitoring satellite completes all observations of the remaining target stars on the same orbital plane after a non-plane flyby. The fastest time required is Time extra :

[0073]

[0074] Among them, T sci and n extrai are the orbital period and angular velocity of the monitoring satellite in the i-th circle after the out-of-plane flyby; f is the phase difference between two satellites in the coplanar uniformly distributed target constellation; ΔAnglei is the phase difference between the monitoring satellite and the initial key target at the i-th circle to the intersection point after the monitoring satellite in the out-of-plane flyby; Time extra To monitor the time required to complete the natural rendezvous with all remaining targets after the satellite's flyby is completed.

[0075] When the monitoring satellite completes the key target orbit change observation, the time required is Time Ctrl , then the shortest time required for the monitoring constellation to complete the observation of the target constellation is:

[0076]

[0077] According to formula (7), the time required for a single monitoring satellite to complete an observation of a target orbital plane is (Time Ctrl +Time allextra ), so each monitoring satellite is responsible for completing (P Tar / Data Sat ) target orbital plane observations, the time required for the monitoring satellite constellation to complete all target observations is the shortest.

[0078] In order to make the physical laws and effects described in the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0079] Reference Figure 1 As shown, a low-to-low multi-satellite observation mission planning and design method of the present invention comprises the following steps:

[0080] S10: Determine the orbital deployment parameters of the target constellation in the low-to-low multi-satellite observation mission system. The orbital deployment parameters of the target constellation specifically include: the orbital height H of the target constellation Tar , the target constellation orbit inclination i Tar , the number of orbital planes of the target constellation P Tar The number of satellites N in the same orbital plane as the target constellation Tar value;

[0081] Specifically, the target constellation is a satellite of Starlink with an orbital height of 550 km and an orbital inclination of 53°. The target constellation belongs to the first shell of Starlink, and is evenly distributed in 72 orbital planes with ascending node right ascension, and each orbital plane has 22 satellites. Therefore, in this example, the orbital height of the target constellation H Tar =550km, orbital inclination i Tar =53°, orbital plane number P Tar =72, the number of satellites in the same orbital plane N Tar =22.

[0082] S20: Determine the orbital altitude of the monitoring satellite with reference to the orbital altitude distribution characteristics of the target constellation;

[0083] Combined with the orbital deployment parameters of the target constellation, according to the theory of flyby rendezvous and the characteristics of space orbit operation, the monitoring satellite must meet the following two conditions for a limited-time flyby rendezvous with the target satellite:

[0084] (1) Relationship between relative angular velocity and time required for cross-plane rendezvous

[0085] When the latitude angle values ​​of the monitoring satellite and the target satellite are u s0 and u t0 , then the latitude angle difference between the monitoring satellite and the target satellite can be expressed as Δu st =u t0 -u s0 ; The angular velocities of the monitoring satellite and the target satellite are and The orbital angular velocity difference between the monitoring satellite and the target satellite is Then the time required for the monitoring satellite to intersect the target star in the monitoring satellite orbit is:

[0086]

[0087] Taking the out-of-plane rendezvous time of less than 3 days as an example, the requirements for calculating the relative angular velocity are as follows.

[0088] if but If Δu st =u t0 -us0 <0, then for any orbit, the maximum latitude argument difference is |Δu st |=360, If Δu st =u t0 -u s0 > 0, then for any orbit, the maximum latitude argument difference is Δu st =360,

[0089] if but If Δu st =u t0 -u s0 <0, then for any orbit, the maximum latitude argument difference is Δu st =-360, the minimum is 0, If Δu st =u t0 -u s0 > 0, then for any orbit, the maximum latitude argument difference is Δu st =360,

[0090] In summary, if the cross-plane rendezvous time is required to be less than 3 days, then Therefore, the orbital angular velocity of the monitoring satellite meets the following conditions:

[0091]

[0092] Among them, a t is the semi-major axis of the target orbit, a t =R e +H Sat , Earth radius R e =6378.137km, Earth's gravitational parameter μ = 398600.4415km 3 / s 2 .

[0093] Considering the eccentricity e of the first shell orbit of Starlink Tar is 0, the orbit height H Tar =550km, when the flyby rendezvous time is less than 3 days, the orbital height of the monitoring satellite H is calculated according to formula (9): sat The following conditions are met:

[0094]

[0095] When the monitoring satellite orbit height H Sat =945.863km, then the angular velocity difference between it and the target orbit is as follows:

[0096]

[0097] The semi-major axis a of the monitoring satellite orbit is calculated by formula (11): s =7324km, its relative angular velocity with the target satellite meets the requirement that the out-of-plane rendezvous time is less than 3 days.

[0098] (2) Relationship between the radial difference at the intersection point and the required fuel

[0099] When designing the maneuvering strategy for out-of-plane flying, the minimum fuel consumption that meets the mission load constraints is generally considered, that is, the intersection points with smaller radius vector differences are considered as the points for out-of-plane flying.

[0100] Assume that the radial differences between the monitoring satellite and the target constellation at the two intersection points are Δr A and Δr B , and Δr A <Δr B , if point A satisfies the mission load constraint, then point A is selected as the point for the out-of-plane flyby, and the radial vector difference with the target during the flyby is 0, and the required velocity increment is calculated as follows.

[0101]

[0102] Among them, a s To monitor the semi-major axis of the satellite orbit, the unit is km; Earth gravity parameter μ = 398600.4415 km 3 / s 2 ; T s is the satellite orbit period, in seconds; Δr A is the radial difference, in m, then the transfer Δr A The radial difference requires a velocity increment of Δv A .

[0103] According to formula (12), the greater the relative orbital angular velocity, the shorter the time required for out-of-plane rendezvous; the smaller the radius vector difference at the intersection point, the less fuel required.

[0104] S30: Determine the number of orbital planes that the monitoring satellite system needs to deploy and the number of monitoring satellites per plane in combination with the orbital deployment-related parameters of the target constellation and the mission time requirements;

[0105] Taking the Starlink Shell 1 constellation as the target orbit, Starlink Shell 1 is deployed on an orbit of 550km and 53° inclination, with a total of 72 orbital planes. The right ascension of the ascending node is evenly distributed at intervals of 5°. The radial vector difference (radial vector difference determines fuel consumption) of the intersection point with the monitoring satellite is analyzed as follows: Figure 2As shown in the figure, when the semi-major axis, eccentricity and orbital inclination are determined, the smaller the right ascension difference between the ascending node of the surveillance satellite and the target, the smaller the radial vector difference at the intersection point, that is, the smaller the orbital plane angle, the smaller the radial vector difference at the intersection point, and the less fuel consumption is required.

[0106] The vector radius difference at the intersection point determines the minimum fuel consumption of the out-of-plane flyby mission. Figure 2 It can be seen that for the target of the "Starlink" shell 1, the minimum radial difference is 30km (fuel consumption is 7.5545m / s), and the maximum radial difference is 255km (fuel consumption is 64.213534m / s). Considering that an orbital plane performs at least one close-range observation mission, the required velocity increment can be calculated as ΔV according to formula (13): st =7050m / s:

[0107]

[0108] Among them, Δr j and Δv j It is the rendezvous radius vector difference and required velocity increment of a single monitoring satellite for a single target on the jth surface.

[0109] When the velocity increment provided by the fuel carried by the monitoring satellite is ΔV = 1200m / s, at least Date needs to be deployed Sat =6 Number of monitored satellites:

[0110] Date Sat =ceil(ΔV st / ΔV)=ceil(7050 / 1200) (14)

[0111] In order to effectively reduce fuel consumption and launch costs, the six monitoring satellites are deployed at 360° of ascending node right ascension. Therefore, the monitoring satellite constellation consists of six orbital planes, each containing one satellite.

[0112] S40: Analyze the mission requirements and propose a mission planning strategy for a single satellite to multiple satellites based on the specific mission given;

[0113] The orbital parameters E of a single surveillance satellite are known. s and target focus focus target track E T0 The parameters are shown in Table 1 below:

[0114] Table 1 Orbital parameters of single surveillance satellites and key targets of Starlink Shell 1

[0115] parameter Surveillance Satellite Starlink Shell 1 Key Targets Semi-major axis (m) 7324000 6928137 Eccentricity 0.0278624000000000 0 Orbital inclination (°) 99.2116000000000 53 Ascending node right ascension (°) 0 0 Argument of perigee (°) 0 0 True anomaly (°) 0 0

[0116] The goal of autonomous mission planning is to design an orbit change strategy for the zeroth target to perform close-range rendezvous imaging, and after imaging the key target, perform natural rendezvous imaging on other targets in the target set as much as possible. The control strategy planning of the surveillance satellite for a single key target is completed by referring to the following optimization indicators: a) Determine the rendezvous orbit parameter set that satisfies the close-range observation of the key target based on the payload observation constraint; b) Determine the control strategy that meets the rendezvous parameter requirements based on the Lambert principle and measurement and control resource constraints; c) Determine the post-control orbit based on the control strategy and calculate the natural rendezvous opportunities of the remaining target stars on the same orbital plane; d) Based on "the closest rendezvous distance to the key target" and "more natural rendezvous opportunities on the post-control orbit". Through the out-of-plane flyby mission planning algorithm, the control sequence of the surveillance satellite for the "Starlink" shell layer 1 key target is as shown in the following table.

[0117] Table 2. Control sequence of a single surveillance satellite flying over a key target in the Starlink shell 1

[0118]

[0119] Finally, the control strategy with the best performance of the above indicators is used as the mission planning strategy for a single satellite to multiple satellites.

[0120] S50: Complete the simulation analysis of multiple satellites on multiple targets and give the results of low-to-low multi-satellite observation mission.

[0121] The key targets of each monitoring satellite’s orbit change observation and the natural flyby observation order of other targets in the same orbital plane are clarified. Combined with the control strategy in step S40, the orbital period of the monitoring satellite after the orbit change control of the key target is 5999s. After the out-of-plane flyby, the phase difference between the intersection point and the key target of the “Starlink” shell layer 1 is about 16.3°. When each target orbital plane is evenly deployed with N Tar =22 satellites, then the phase difference of these 22 satellites is 16.36°, so the monitoring satellite runs m circles after the out-of-plane flyby, and there is a phase difference of about m*16.36° with the key target of the orbit change observation at the intersection point, m=1,2,3…N (m is a positive integer), then it can intersect with a satellite on the orbital plane. For example, if m=1, the monitoring satellite will perform an out-of-plane flyby on the key target at the intersection point and then run 1 circle and return to the intersection point again. At this time, there is a phase difference of about 16.3° between the monitoring satellite and the key target. The monitoring satellite has visibility with the target stars adjacent to the key target (phase difference of 16.3°). Therefore, it takes at least time Time for a monitoring satellite to complete all observations of the remaining target set on the same plane after an out-of-plane flyby. extra :

[0122]

[0123] Among them, T sci and nextrai are the orbital period and angular velocity of the monitoring satellite in the i-th circle after the out-of-plane flyby; f is the phase difference between two satellites in the coplanar uniformly distributed target constellation; ΔAnglei is the phase difference between the monitoring satellite and the initial key target at the i-th circle to the intersection point after the monitoring satellite in the out-of-plane flyby; Time extra To monitor the time required to complete the natural rendezvous with all remaining targets after the satellite's flyby is completed.

[0124] When the monitoring satellite runs 13.8 orbits per day, there are about 13 imaging opportunities per day, and 22 targets can be imaged in Time. extra = 2 days to complete all observations. Assume that the time required for the satellite to complete the orbit change observation of key targets is Time Ctrl =3, then the shortest time required for the monitoring satellite constellation to complete the observation of the target constellation is:

[0125]

[0126] According to formula (16), the time required for a single surveillance satellite to complete a target orbital plane observation is (Time Ctrl +Time allextra )=(3+2)=5 days. The specific time for natural conjunction observation is as follows: Figure 3 ,As can be seen from the figure, different satellites in the orbital plane can be observed in each circle.

[0127] There are 72 orbital planes in the Starlink shell 1, and each monitoring satellite is responsible for completing (P Tar / Data Sat ) = 12 orbital planes, and one orbital plane requires 5 days to complete the maneuvering and imaging, so it takes about 60 days to complete the 100% full-domain observation of the Starlink shell 1.

[0128] From the above examples, it can be seen that the present invention solves the problem of narrow imaging window of traditional single satellite single target flyby mission by proposing a low-to-low multi-satellite observation mission planning and design method. When the observation opportunity is missed, the monitoring satellite can continue to perform natural rendezvous observation missions on other targets, effectively improving the observation efficiency of monitoring satellite orbit change.

[0129] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-to-low multi-satellite observation mission planning and design method, characterized in that: The specific steps are as follows: Step 1) Determine the orbital deployment parameters of the target constellation in the low-to-low multi-satellite observation mission system. The orbital deployment parameters of the target constellation specifically include: the orbital height H of the target constellation Tar , the target constellation orbit inclination i Tar , the number of orbital planes of the target constellation P Tar The number of satellites N in the same orbital plane as the target constellation Tar value; Step 2) determining the orbital altitude of the monitoring satellite with reference to the orbital altitude distribution characteristics of the target constellation; Step 3) Determine the number of orbital planes that the monitoring satellite system needs to deploy and the number of monitoring satellites per plane in combination with the target constellation orbit deployment related parameters and mission time requirements; Step 4) Analyze the mission requirements and propose a single satellite to multiple satellite mission planning strategy based on the given specific mission; Step 5) Complete the simulation analysis of multiple satellites on multiple targets and give the results of the low-to-low multi-satellite observation mission.

2. The method for planning and designing a low-to-low multi-satellite observation mission according to claim 1, characterized in that: The step 2) is specifically as follows: Combined with the orbital deployment parameters of the target constellation, according to the theory of flyby rendezvous and the characteristics of space orbit, the premise of whether the monitoring satellite can conduct a limited-time flyby rendezvous with the target satellite includes two items: (1) Does the relative angular velocity meet the following conditions: If the cross-plane rendezvous time is required to be less than K days, then in, To monitor the orbital angular velocity difference between the satellite and the target star; (2) Whether the radial difference at the intersection point meets the fuel constraint: The greater the relative orbital angular velocity, the shorter the time required for out-of-plane rendezvous; the smaller the difference in radial vectors at the intersection point, the less fuel required; When the orbital eccentricity of the target constellation is e Tar Equal to 0, the target constellation orbit height is H Tar , requiring the time of cross-plane rendezvous to be less than K days, then The monitoring satellite orbit height H Sat Need to meet: Where a is the semi-major axis of the satellite orbit, a s and a t are the semi-major axes of the monitoring satellite and target satellite orbits respectively; n is the angular velocity of the satellite orbit, To monitor the angular velocity of the satellite, is the angular velocity of the target star; the radius of the earth R e =6378.137km, Earth's gravitational parameter μ = 398600.4415km 3 / s 2 ; According to formula (3), the orbital height H of the monitoring satellite that meets the specified mission duration is calculated sat .

3. The method for planning and designing a low-to-low multi-satellite observation mission according to claim 2, characterized in that: The step 3) is as follows: Considering that a target constellation orbital plane needs to perform at least one close-range observation mission, the total velocity increment ΔV is required. st for: Among them, T s To monitor the satellite orbit period, Δr j and Δv j is the rendezvous radius difference and required velocity increment of a single monitoring satellite to a single target star on the jth plane; When the velocity increment provided by the fuel carried by the monitoring satellite is ΔV m / s, at least the number of monitoring satellites required to be deployed is Date Sat for: Date Sat =ceil(ΔV st / ΔV) (5) In order to effectively reduce fuel consumption and launch costs, Date Sat The monitoring satellites are deployed equally at 360° of the ascending node longitude; therefore, the monitoring satellite constellation consists of one satellite per orbital plane. Sat The orbital surface is composed of 4. The method for planning and designing a low-to-low multi-satellite observation mission according to claim 3, characterized in that: The specific steps of step 4) are as follows: The orbital parameters of a single monitoring satellite are known to be E s , the target constellation orbit parameter set is [E T0 ,E T1 ,E T2 ,...E TN ], where the 0th target constellation is the key target; the goal of autonomous mission planning is to design a trajectory change strategy for the 0th target to perform close-range rendezvous imaging, and after imaging the key target, perform natural rendezvous imaging on other targets in the target set as much as possible; The specific planning process is as follows: a) Determine the rendezvous orbit parameter set that satisfies the close-range observation of key targets based on the payload observation constraints; b) Determine the control strategy that meets the rendezvous parameter requirements based on the Lambert principle and the measurement and control resource constraints; c) Determine the post-control orbit based on the control strategy and calculate the natural rendezvous opportunities of the remaining target stars on the same orbital plane; d) Optimize and select the final control strategy based on the indicators of "shortest rendezvous distance with key targets" and "more natural rendezvous opportunities on the post-control orbit"; finally, the control strategy with the best indicators is used as the mission planning strategy for a single satellite to multiple satellites.

5. The method for planning and designing a low-to-low multi-satellite observation mission according to claim 4, characterized in that: The step 5) is specifically as follows: Clearly define the key targets for each monitoring satellite's orbit change observation and the natural flyby observation order of other targets in the same orbital plane; uniformly deploy N satellites on each orbital plane of the target constellation. Tar target stars, then this N Tar The phase difference between the target stars is (360 / N Tar )°, when the monitoring satellite runs m circles after the out-of-plane flyby, there is a phase difference of about m*(360 / N Tar )°, m=1,2,3…N, m is a positive integer, then it can intersect with a satellite on the orbital plane; therefore, a monitoring satellite completes all observations of the remaining target stars on the same orbital plane after a non-plane flyby, and the fastest time required is Time extra : Among them, T sci and n extrai are the orbital period and angular velocity of the monitoring satellite in the i-th circle after the out-of-plane flyby; f is the phase difference between two satellites in the coplanar uniformly distributed target constellation; ΔAnglei is the phase difference between the monitoring satellite and the initial key target at the i-th circle to the intersection point after the monitoring satellite in the out-of-plane flyby; Time extra To monitor the time required to complete the natural rendezvous with all remaining targets after the satellite flyby is completed; When the monitoring satellite completes the key target orbit change observation, the time required is Time Ctrl , then the shortest time required for the monitoring constellation to complete the observation of the target constellation is: According to formula (7), the time required for a single monitoring satellite to complete an observation of a target orbital plane is (Time C trl+Timeallextra), so each monitoring satellite is responsible for completing (P Tar / Data Sat ) target orbital plane observations, the time required for the monitoring satellite constellation to complete all target observations is the shortest.

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