Multi-satellite real-time orbit determination method under one rocket multi-satellite mode

Abstract

The application discloses a multi-satellite real-time orbit determination method in a one-launch-multiple-satellite mode, which comprises the following steps: building a one-launch-multiple-satellite real-time orbit determination system; dividing the multi-satellite orbit determination into different calculation work groups according to the satellite-launcher separation sequence, each calculation work group corresponding to one satellite-launcher separation; distributing each satellite to the corresponding calculation work group according to the satellite-launcher separation process; each satellite corresponding to an independent orbit determination program; the single-satellite orbit determination program in the calculation work group only collects orbit determination data without running the orbit determination calculation process when no satellite-launcher separation signal of the satellite is received; and when the satellite-launcher separation signal of the satellite is received, the orbit determination calculation process is started to obtain the initial orbit of the satellite.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of commercial spaceflight TT&C technology, and relates to a multi-satellite real-time orbit determination method in a one-launch-multiple-satellite mode. BACKGROUND

[0002] In recent years, China's aerospace field has made breakthrough progress in commercial spaceflight. With the rise of commercial spaceflight, the characteristics of commercial satellite launch missions are showing miniaturization, diversification, low-cost development, and high-precision orbiting. In the future, a large number of commercial satellite launch missions will use one-launch-multiple-satellite technology.

[0003] One-launch-multiple-satellite refers to the technology of simultaneously or sequentially launching several satellites into Earth orbit by one launch vehicle. Generally, there are two ways to launch one-launch-multiple-satellite: the first way is to release multiple satellites at the same time and launch them into the same or similar predetermined orbits; the second way is to release satellites in batches, i.e., when the launch vehicle reaches a certain predetermined orbit, the first satellite is released to enter the first type of orbit, then the launch vehicle continues to fly to another predetermined orbit, and the second satellite is released, and so on, until all satellites are launched into their respective predetermined orbits. The current one-launch-multiple-satellite technology combines the use of the above two methods, i.e., in one launch mission, the launch vehicle and the satellites will separate multiple times, and each time the launch vehicle will launch several satellites into their respective predetermined orbits.

[0004] One-launch-multiple-satellite missions are missions in which all satellites are launched into predetermined orbits. An important part of the mission is to quickly calculate the initial orbit of the satellite, calculate the orbiting parameters of the satellite, and then assess whether the satellite has entered the predetermined orbit. In addition, the initial orbit of the satellite is the basis for all subsequent satellite activities (such as calculating tracking time and orbit improvement), and if the initial orbit of the satellite cannot be calculated, subsequent work cannot be carried out. Therefore, quickly calculating the initial orbit of multiple satellites is a very important part of one-launch-multiple-satellite missions. Currently, the time requirement for the rapid notification of the orbit for some important missions is to notify the initial orbit of the satellite within 30 seconds from the moment the satellite and the launch vehicle separate.

[0005] In one-launch-multiple-satellite missions, there are two common methods for real-time orbit determination of multiple satellites: one method is to calculate the initial orbit of each satellite after all satellites and the launch vehicle separate; the other method is to select one satellite as the primary satellite and the others as secondary satellites when each group of satellites and the launch vehicle separate, set the calculation environment for the primary satellite, calculate the initial orbit of the primary satellite, and then estimate the initial orbit of the secondary satellites using some calculation tools software based on the initial orbit of the primary satellite. Both of these two methods for calculating the initial orbit of multiple satellites do not have the ability to notify the initial orbit of the satellite within 30 seconds from the moment the satellite and the launch vehicle separate. SUMMARY

[0006] The application aims to provide a multi-satellite real-time orbit determination method in a one-launch-multiple-satellite mode, and solve the problem of slow orbit determination of multi-satellites in the launch stage in the one-launch-multiple-satellite mode.

[0007] The technical solution adopted by the application is a multi-satellite real-time orbit determination method in a one-launch-multiple-satellite mode, a one-launch-multiple-satellite real-time orbit determination system is built, the orbit determination of multi-satellites is divided into different calculation work groups according to the order of satellite separation, each calculation work group corresponds to a satellite separation, each satellite is allocated to a respective calculation work group according to the satellite separation process, each satellite corresponds to a set of independent orbit determination program, the single-satellite orbit determination program in the calculation work group only collects orbit determination data without running the orbit determination calculation process when no satellite separation signal of the satellite is received, and starts to run the orbit determination calculation process when the satellite separation signal of the satellite is received, and calculates and outputs the initial orbit of the satellite.

[0008] The orbit determination calculation process includes determining the initial orbit of the satellite with the collected satellite orbit determination data, correcting the initial orbit with separation force, and then weighting and sorting the initial orbits corresponding to the orbit determination data of different data sources of the same satellite, and selecting the one with the minimum metric distance as the initial orbit of the satellite.

[0009] The satellite orbit determination data includes three kinds of data source data, namely, the inertial navigation data of the rocket, the GNSS data, and the feature point data at the moment of separation of the rocket and the satellite.

[0010] The initial orbit of the satellite is determined with the collected satellite orbit determination data, the collected data is preprocessed first, including decoding and quantization processing of each data field, outputting position and velocity parameters, compressing high-frequency data, converting position and velocity parameters in different reference coordinate systems into position and velocity parameters in the earth-fixed coordinate system, checking and processing the data for redundancy, and discarding redundant data, and checking and processing the data for correctness and rationality, and discarding incorrect or unreasonable data.

[0011] The initial orbit of the satellite is determined with the collected satellite orbit determination data, including converting the position and velocity parameters in the earth-fixed coordinate system into position and velocity parameters in the J2000 inertial coordinate system, and then converting the position and velocity parameters into six elements of an elliptical orbit as the initial orbit of the satellite.

[0012] The initial orbit of the satellite is determined with the collected satellite orbit determination data, if the satellite orbit determination data includes N points of data, when N = 1, the six elements of the elliptical orbit are directly calculated with the point data as the initial orbit output; when N = 2, the position average value and the velocity average value are calculated first and Calculate the six elements of elliptical orbit as initial orbit output; when N≥3, calculate the mean value of position and velocity of all points and velocity Then calculate the metric distance of position parameters and velocity parameters with the mean value , eliminate the two data points with the largest metric distance, then the orbit data is N-2 point data, calculate the metric distance of the remaining orbit data with the corresponding position and velocity mean value, and take the point data with the smallest metric distance to calculate the six elements of elliptical orbit as initial orbit output.

[0013] Convert the position parameters and velocity parameters into the six elements of elliptical orbit, which specifically includes the following steps:

[0014] Step 1, convert the position and velocity parameters into semi-major axis a

[0015]

[0016]

[0017] Step 2, calculate the eccentricity e

[0018]

[0019] Step 3, calculate the mean anomaly M

[0020]

[0021] M=E-esinE (5)

[0022] Step 4, calculate the inclination i

[0023]

[0024]

[0025]

[0026]

[0027] i=cos -1 (R z ) (10)

[0028] Step 5, calculate the ascending node longitude Ω

[0029]

[0030] Step 6, calculate the argument of periapsis ω

[0031]

[0032] Calculate the position average of all point data and velocity average where

[0033]

[0034]

[0035] where x ave represents the average of the x coordinate of all point position vectors, y ave represents the average of the y coordinate of all point position vectors, and z ave represents the average of the z coordinate of all point position vectors, represents the average of the x coordinate of all point velocity vectors, represents the average of the y coordinate of all point velocity vectors, represents the average of the z coordinate of all point velocity vectors, i = 1, …, N.

[0036] Calculate the position parameters of all points and velocity parameters and the metric distance d i of the average value where

[0037]

[0038] The initial orbits corresponding to the orbiting data of different data sources of the same satellite are weighted and sorted, specifically including the following steps:

[0039] Step 1, define the position and velocity parameters of the rocket inertial navigation data as the position and velocity parameters of the GNSS data as the position and velocity parameters of the feature point data at the moment of rocket and satellite separation as Let the weights of the three types of data be w I , w G , and w S , and w I +w G +w S = 1, calculate the weighted average of the position and velocity parameters of the three types of data where

[0040]

[0041] Step 2, calculate the metric distance between the position and velocity parameters of the three types of data and the weighted average value

[0042]

[0043] Step 3, sort the three metric distances d I , d G , d S , the smaller value is in front, and the larger value is in back.

[0044] The beneficial effects of the present application are that the problem of rapid orbit determination of multiple satellites in commercial satellite launch mission is solved, by designing independent orbit determination programs for each satellite, collecting orbit determination data in advance, after receiving the satellite-rocket separation signal, immediately starting orbit determination calculation, optimization sorting and outputting the orbit; each satellite-rocket separation calculates and outputs the initial orbit of the separated satellites in this batch, which meets the requirement of rapid reporting of the initial orbit of the satellite after the satellite-rocket separation from the system architecture. The present application defines a metric distance for the same kind of data source and different time data, selects the optimal orbit determination data source by the metric distance; for different kinds of data sources and satellite-rocket separation time orbits, the method of combining weighted sorting and metric distance is used for optimization, which ensures the authenticity and objectivity of the satellite orbit data source, and at the same time ensures the simplicity and efficiency of the orbit optimization calculation method, which meets the requirement of rapid reporting of the initial orbit of the satellite after the satellite-rocket separation from the orbit determination calculation. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is the topological structure diagram of the orbit determination calculation work group and the satellite in the embodiment of the present application. DETAILED DESCRIPTION

[0046] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0047] The multi-satellite real-time orbit determination method in the one-rocket-multiple-satellite mode of the present application comprises building a one-rocket-multiple-satellite real-time orbit determination system, dividing the multi-satellite orbit determination into different calculation work groups according to the satellite-rocket separation sequence, each calculation work group corresponding to one satellite-rocket separation, for example, one rocket 8 satellites in a certain task, the rocket releases the satellites in 3 times, the first time releases 3 satellites, the second time releases 3 satellites, and the third time releases 2 satellites, then including three calculation work groups, and the topological structure is as shown in Figure 1 .

[0048] According to the satellite-rocket separation process, each satellite is allocated to the respective calculation work group, that is, satellite 1, satellite 2 and satellite 3 belong to the first calculation work group, satellite 4, satellite 5 and satellite 6 belong to the second calculation work group, and satellite 7 and satellite 8 belong to the third calculation work group, each satellite corresponds to a set of independent orbit determination program, and the single-satellite orbit determination program in the calculation work group only collects orbit determination data without running the orbit determination calculation process when the satellite-rocket separation signal of the satellite is not received, and starts to run the orbit determination calculation process to obtain the initial orbit of the satellite when the satellite-rocket separation signal of the satellite is received.

[0049] The orbit determination calculation process specifically includes the following steps:

[0050] Step 1: Determine the initial orbit of the satellite using the collected satellite orbit determination data.

[0051] (1) Preprocess the collected data from the three data sources, including decoding and quantizing each data field, outputting position and velocity parameters, compressing high-frequency data, converting position and velocity parameters under different reference coordinate systems into position and velocity parameters under the Earth-fixed coordinate system, performing data duplication checks, discarding redundant duplicate data, and performing data correctness and rationality checks, discarding incorrect or unreasonable data.

[0052] The three data sources are rocket inertial navigation data, GNSS data, and feature point data at the moment of rocket-satellite separation.

[0053] (2) Convert the position and velocity parameters in the Earth-fixed coordinate system to the position and velocity parameters in the J2000 inertial coordinate system, and then convert the position parameters... and speed parameters Converting the satellite into an elliptical orbit using the six-element number as its initial orbit involves the following steps:

[0054] (2.1) Convert the position and velocity parameters into semi-major axis a

[0055]

[0056]

[0057] (2.2) Calculate the eccentricity e

[0058]

[0059] (2.3) Calculate the angle M of the mean anterior point

[0060]

[0061] M = E - esinE (5)

[0062] (2.4) Calculate the tilt angle i

[0063]

[0064]

[0065]

[0066]

[0067] i = cos-1 (R z (10)

[0068] (2.5) Calculate the right ascension Ω of the ascending node

[0069]

[0070] (2.6) Calculate the argument ω of perigee

[0071]

[0072] (3) If the satellite orbit determination data includes N-point data

[0073] When N=1, the data at that point is used to calculate the six elements of the elliptical orbit and output them as the initial orbit.

[0074] When N=2, first calculate the average position of the two data points. and average speed Then use and Calculate the six elements of the elliptical orbit and output them as the initial orbit.

[0075] When N≥3, the processing steps are as follows:

[0076] (3.1) Calculate the average location value of all point data. and average speed in

[0077]

[0078]

[0079] In the formula, x ave The x-coordinate represents the average of the x-coordinates in the position vectors of all points, and the y-coordinate represents the average of the x-coordinates. ave The z-coordinate represents the average of the y-coordinates in the vector of all point positions. ave This represents the average z-coordinate of the position vectors of all points. This represents the average x-coordinate of the velocity vectors at all points. This represents the average y-coordinate of the velocity vectors at all points. Let z represent the average z-coordinate of the velocity vectors of all points, i = 1, ..., N;

[0080] (3.2) Calculate the location parameters of all points and speed parameters Compared with the average metric distance d i ,in

[0081]

[0082] (3.3) Remove the two largest data points in the metric distance, and the orbit data is N-2 point data. Calculate the metric distance between the remaining orbit data and the corresponding position and velocity average value, and take the point data with the smallest metric distance to calculate the six elements of the elliptical orbit as the initial orbit output.

[0083] Step two, separate force correction is carried out on the initial orbit, and the specific steps are as follows:

[0084] (1) The separation force of the satellite-rocket separation time is decomposed into three coordinate axes of the J2000 inertial coordinate system, which becomes

[0085] (2) Add to the velocity parameter , and the velocity parameter after separation force correction is

[0086] (3) Convert the position parameter and the velocity parameter into elliptical six elements (a, e, i, Ω, ω, M), and output the initial orbit after correction of the separation force.

[0087] Step three, the modified initial orbit corresponding to the orbiting data of different data sources of the same satellite is weighted and sorted, and the one with the smallest metric distance is selected as the initial orbit of the satellite.

[0088] Specifically, the following steps are included:

[0089] Step 1, define the inertial navigation data position and velocity parameters of the rocket as The GNSS data position and velocity parameters are The position and velocity parameters of the characteristic point data at the rocket-satellite separation time are Let the weights of the three types of data be w I , w G , w S , and w I +w G +w S =1, and calculate the weighted average of the position and velocity parameters of the three types of data where

[0090]

[0091] Step 2, calculate the metric distance between the position and velocity parameters of the three types of data and the weighted average value

[0092]

[0093] Step 3, calculate the three metric distances d I ​、d G 、d S The sorting is performed with the smaller values placed in front and the larger values placed in back.

Claims

1. A multi-satellite real-time orbit determination method in a multiple launch vehicle multiple satellite (MLVMS) mode, characterized in that, A real-time orbit determination system for multiple satellites launched by one rocket is built, and orbit determination of multiple satellites is divided into different calculation groups according to the sequence of satellite-rocket separation, each calculation group corresponds to one satellite-rocket separation, each satellite is allocated to the corresponding calculation group according to the satellite-rocket separation process, each satellite corresponds to an independent orbit determination program, and the single-satellite orbit determination program in the calculation group only collects orbit determination data without running the orbit determination calculation process when the satellite-rocket separation signal of the satellite is not received, and starts to run the orbit determination calculation process when the satellite-rocket separation signal of the satellite is received, and obtains the initial orbit of the satellite; The orbit determination calculation process includes determining the initial orbit of the satellite by using the collected satellite orbit determination data, correcting the initial orbit by using the separation force, and then weighting and sorting the initial orbits corresponding to the orbit determination data of different data sources of the same satellite, and selecting the initial orbit with the minimum metric distance as the initial orbit of the satellite; the satellite orbit determination data includes three kinds of data source data, which are the inertial navigation data of the rocket, the GNSS data, and the feature point data at the moment of separation of the rocket and the satellite, the initial orbit of the satellite is determined by using the collected satellite orbit determination data, the collected data is preprocessed first, including decoding and quantization processing of each data field, outputting position and velocity parameters, compressing high-frequency data, converting position and velocity parameters in different reference coordinate systems into position and velocity parameters in the earth-fixed coordinate system, checking and processing the data for repeatability, discarding redundant repeated data, and checking and processing the data for correctness and rationality, and discarding incorrect or unreasonable data; The initial orbit of the satellite is determined by using the collected satellite orbit determination data, including converting the position and velocity parameters in the earth-fixed coordinate system into the position and velocity parameters in the J2000 inertial coordinate system, and then converting the position and velocity parameters into six elements of an elliptical orbit as the initial orbit of the satellite.

2. The method according to claim 1, wherein, Determine the initial orbit of satellite with collected satellite orbit determination data, if the satellite orbit determination data includes N point data, when N=1, directly calculate the six parameters of elliptical orbit with the point data as initial orbit output; when N=2, first calculate the position average value and the speed average value of the two point data, then calculate the six parameters of elliptical orbit with and as initial orbit output; when N≥3, calculate the position average value and the speed average value of all point data, then calculate the measure distance of all point position parameters and speed parameters with the average value , , eliminate the two data points with the largest measure distance, then the orbit determination data is N-2 point data, calculate the measure distance of the remaining orbit determination data with the corresponding position and speed average value, take the point data with the smallest measure distance to calculate the six parameters of elliptical orbit as initial orbit output.

3. The method according to claim 2, wherein, converting the position parameters and the velocity parameters into elliptical orbit elements, comprising the steps of: Step 1, converting position, velocity parameters to semi-major axis a （1） （2） Step 2, calculate eccentricity e （3） Step 3, Calculate the plane's mean anomaly M （4） （5） Step 4, calculating the tilt angle i （6） （7） （8） （9） （10） Step 5, calculate the ascending node right ascension Ω （11） Step 6, Calculate Argument of Perigee Calculate the metric distance, the specific steps are as follows: （12）。 4. The method of claim 2, wherein, Correct the initial orbit by using the separation force, the specific steps are as follows: Step 1, calculate the position mean of all point data and velocity mean where （13） （14） wherein denotes the average of the x-coordinates of all point position vectors, denotes the average of the y-coordinates of all point position vectors, denotes the average of the z-coordinates of all point position vectors, denotes the average of the x-coordinates of all point velocity vectors, denotes the average of the y-coordinates of all point velocity vectors, denotes the average of the z-coordinates of all point velocity vectors, i = 1,..., N; Step 2, calculate all point position parameters and velocity parameters from the mean , measure distance , （15）。 5. The method of claim 2, wherein, Weighting and sorting the initial orbits corresponding to the orbit determination data of different data sources of the same satellite, specifically including the following steps: (1) Separation force at the moment of separation of the satellite and the missile Decomposed into three coordinate axes of the J2000 inertial coordinate system, it becomes ; (2) the velocity parameter is accumulated to the velocity parameter ;​​ (3) Convert the position parameters , velocity parameters into elliptic elements, output the initial orbit after correction of the perturbation forces.

6. The multi-satellite real-time orbit determination method in the multi-satellite launch mode according to claim 4, characterized in that, Step 2, calculate the metric distance between the position and velocity parameters of the three types of data and the weighted average value Step 1, define the inertial navigation data position, velocity parameters of the rocket respectively as , , the GNSS data position, velocity parameters respectively as , , the feature point data position, velocity parameters at the moment of the rocket and satellite separation respectively as , , set the weights of the three types of data respectively as , , , and , calculate the weighted average value of the three types of data position, velocity parameters , , wherein （16） ​ （17） Step 3. Sort the three metric distances , , with the smallest value first and the largest value last.

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