Remote sensing data multichannel downloading control optimization method and system based on orbit recursion

Abstract

The invention provides a remote sensing data multichannel downloading control optimization method and system based on orbit recursion, and the method comprises the steps: obtaining the initial orbit parameter of a local satellite, carrying out the orbit recursion according to the initial orbit parameter of the local satellite, and calculating the position vector parameter of the local satellite and the elevation angle between the local satellite and a DPT station; acquiring a laser receiving satellite, namely an initial orbit value of the opposite satellite, recurring the orbit of the opposite satellite, and acquiring a position vector parameter of the opposite satellite; extracting data transmission and relay microwave link task job table information to obtain a data transmission and relay microwave link job time interval, and maintaining the data transmission and relay microwave link task job table; and respectively carrying out strategy optimization control after arc section overlapping of the DPT link and the data transmission relay microwave link, strategy optimization control after arc section overlapping of the DPT link and the laser inter-satellite link, and strategy optimization control after overlapping of the laser inter-satellite link and the data transmission relay microwave link. The method is used for designing and optimizing a remote sensing data multi-channel downloading control strategy, formulating a priority principle and solving the problem of arc section overlapping conflict.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular, to an optimization method and system for multi-channel downlink control of remote sensing data based on orbit recursion. Background Art

[0002] With the continuous enhancement of the observation capabilities of remote sensing satellites in terms of high temporal resolution, high spatial resolution, and high spectral resolution, the satellites will obtain a vast amount of remote sensing data. Relying solely on the traditional working mode of downlink through the microwave channels of ground stations, restricted by factors such as the coverage range of ground stations, communication duration, and low transmission rate, it is difficult to meet the demand for the complete and timely downlink of the vast amount of remote sensing data.

[0003] It has become a development trend for remote sensing satellites to add data transmission relay channels and inter-satellite laser channels for downlinking remote sensing data. After the addition, the on-board remote sensing data involves multi-channel downlink. How to achieve autonomous optimal control is an urgent problem to be solved. The method and system for calculating the attitude deviation compensation amount of inter-satellite laser communication are used for high-precision pointing and aiming of laser terminals, and solve the problem that laser communication cannot establish a link caused by satellite attitude deviation.

[0004] Patent document CN107257255A discloses a satellite intelligent transmission system and method, including calculating the transmission requirements and data volume according to the transmission requirements on the ground and the satellite overpass time, selecting a matching transmission rate and downloading files, and realizing the transmission of remote sensing data between the satellite and the ground. However, this patent document requires the remote sensing data to be uploaded in advance on the ground and only completes the downlink of part of the data.

[0005] Patent document CN102142189B discloses a multi-channel telemetry transmission system, including: on-board TT&C; on-board computer; on-board data transmission; 1553B bus. By increasing the transmission rate, it alleviates the problem that the medium and low Earth orbit telemetry system cannot solve the problem of global 1:1 recording and transmission of large-capacity telemetry data, and does not involve the orbit recursion autonomous multi-ground station and inter-satellite laser transmission scheme.

[0006] Patent document CN108023636A discloses a method and system for obtaining remote sensing data in a limited area, a server, and an intelligent terminal, including: receiving a data request sent by the intelligent terminal; wherein, the data request is generated according to a selected target area; determining the overpassing satellite in the current target area according to the data request; generating a control instruction according to the data request and sending it; receiving the real-time remote sensing data of the target area collected by the overpassing satellite executing the control instruction; and sending the real-time remote sensing data to the corresponding intelligent terminal for the intelligent terminal to extract the required information. However, this patent document only completes the downlink of remote sensing data in the hot target area and does not involve on-board orbit recursion and ground station selection.

[0007] Patent document CN108988927A discloses a highly reliable data transmission working mode, which is divided into a normal working mode, a derated working mode and a user-defined mode. In this working mode, there are 2 ground data transmission channels on the satellite body. The maximum capacity of each data transmission channel is 300 Mbps. Payload data can be downloaded simultaneously through 2 data transmission channels, and the types of payload data downloaded through the 2 data transmission channels can be independently selected or blocked through uplink commands; the 2 data transmission channels simultaneously support a downlink capacity of 150 Mbps at a reduced code rate. Although this patent document improves the reliability of remote sensing data transmission, it does not solve the problem that not all remote sensing data can be downloaded in time due to its large volume.

[0008] Patent document CN103678515A discloses a space station extensible and massive remote sensing information processing system, including: three types of general remote sensing data interfaces, a large-capacity high-speed data cache DDR2, an image processing control anti-fuse FPGA, an image processing module SRAM-type FPGA, an image processing module SRAM-type FPGA configuration program storage PROM, an image processing module SRAM-type FPGA configuration program storage EEPROM, a compression processing chip, an image processing module operation parameter storage EEPROM, a high-speed backplane, an encoding control anti-fuse FPGA, a system control parameter storage EEPROM, and an encoding processing chip. However, this patent document does not involve inter-satellite laser transmission, and the ground station functions can be used for data downlink and orbit recursion calculation. Summary of the Invention

[0009] Aiming at the defects in the prior art, the purpose of the present invention is to provide an optimization method and system for multi-channel downlink control of remote sensing data based on orbit recursion.

[0010] An optimization method for multi-channel downlink control of remote sensing data based on orbit recursion provided by the present invention includes:

[0011] The on-orbit satellite remote sensing data downlink channels include an X-band delay link, i.e., a DPT link, a data transmission relay microwave link, and an inter-satellite laser link;

[0012] The steps of the optimization method include:

[0013] Step S1: Obtain the initial orbit parameters of the satellite itself, and perform orbit recursion according to the initial orbit parameters of the satellite itself to calculate the position vector parameters of the satellite itself and the elevation angle between the satellite itself and the DPT station;

[0014] Step S2: Obtain the initial orbit value of the laser receiving satellite, i.e., the other satellite, and recursively calculate the orbit of the other satellite to obtain the position vector parameters of the other satellite;

[0015] Step S3: Extract the information of the data relay microwave link task operation table, obtain the operation time interval of the data relay microwave link, and maintain the data relay microwave link task operation table;

[0016] Step S4: Based on the elevation angle between the satellite and the DPT site and the operation time interval of the data relay microwave link, perform strategy optimization control after the arc segments of the DPT link and the data relay microwave link overlap;

[0017] Step S5: Calculate the time interval of the laser inter-satellite link arc segment according to the position vector parameters of the other satellite, and perform strategy optimization control after the arc segments of the DPT link and the laser inter-satellite link overlap;

[0018] Step S6: Perform strategy optimization control after the laser inter-satellite link and the data relay microwave link overlap.

[0019] Preferably, the step S1 includes:

[0020] Step S1.1: Calculate the satellite position vector parameters, and the formula is as follows:

[0021]

[0022] In the formula, r x , r y , r z respectively represent the three-axis components of the position vector r in the J2000.0 inertial coordinate system, R z (·), R x (·) represent matrix functions, Ω s represents the right ascension of the ascending node of the orbit, i s represents the orbital inclination, ω s represents the argument of perigee of the orbit, r s represents the distance between the satellite and the geocenter, f s represents the true anomaly of the orbit, M s represents the mean anomaly of the orbit, e s represents the eccentricity of the orbit, a s represents the semi-major axis of the orbit;

[0023] Step S1.2: Calculate the position vector of the DPT site, and the calculation formula is as follows:

[0024] Sλ = S Gt + λ s

[0025]

[0026] In the formula, S λ represents the local sidereal time angle, S Gt is the Greenwich sidereal time, λ s is the geographical longitude, is the geocentric latitude, R cs is the geocentric distance. x sta 、y sta 、z sta respectively represent the position vectors of the DPT site;

[0027] Step S1.3: Calculate the elevation angle between the satellite and the DPT site. The calculation formula is as follows:

[0028]

[0029] a = (r x - x sta) / ρ; b = (r y - y sta ) / ρ; c = (r z - z sta ) / ρ

[0030]

[0031] In the formula, ρ represents the distance between the satellite and the DPT site, a, b, and c represent intermediate variables, h w represents the elevation angle of the satellite relative to the ground station, that is, the elevation angle between the satellite and the DPT site.

[0032] Preferably, the step S2 includes:

[0033] Step S2.1: Obtain the initial value of the orbit of the other satellite;

[0034] Step S2.2: Calculate the position vector of the other satellite. The formula is as follows:

[0035]

[0036] Among them, r x_g 、r y_g 、r z_g respectively represent the three-axis components of the position vector r s_g of the other satellite in the J2000.0 inertial coordinate system. Rz(·) and Rx(·) are matrix functions, a<U+ s_g is the semi-major axis of the orbit of the other satellite, e s_g is the eccentricity of the orbit of the other satellite, M s_g is the mean anomaly of the orbit of the other satellite, Ω s_g is the right ascension of the ascending node of the orbit of the other satellite, i s_g is the inclination of the orbit of the other satellite, ω s_g is the argument of periapsis of the orbit of the other satellite. All are the initial orbit parameters of the other satellite, f s_g is the true anomaly of the orbit of the other satellite, r s_g is the distance between the other satellite and the geocenter.

[0037] Preferably, the formulas of the matrix functions are as follows:

[0038]

[0039] Preferably, the information of the data transmission relay microwave link task operation table includes the start time and end time of the relay task;

[0040] Maintaining the data transmission relay microwave link task operation table includes sorting, updating storage, or deleting.

[0041] Preferably, the step S4 includes:

[0042] Step S4.1: Calculate the communication time interval that satisfies the DPT site. When the elevation angle between the satellite and the DPT site is greater than the default DPT site elevation angle ED, communication with the DPT site is satisfied, and record the start time of the current DPT site communication; when the elevation angle between the satellite and the DPT site is less than the default DPT site elevation angle ED, communication with the DPT site is not satisfied, and record the end time of the current DPT site communication to obtain the communication time interval that satisfies the DPT site;

[0043] Step S4.2: Compare the DPT site communication time interval with the data transmission relay microwave link operation time interval to determine whether there is a repetition in the time intervals between the two. If so, it means that the DPT link and the data transmission relay microwave link overlap. Preferentially use DPT for downlink, delete the duplicate instruction packets in the data transmission relay microwave link task operation table, and set the DPT link and data transmission relay microwave link overlap flag Flag_DZct to 1; if not, it means that the DPT link and the data transmission relay microwave link do not overlap, and set the overlap flag Flag_DZct to 0.

[0044] Preferably, the step S5 includes:

[0045] Step S5.1: Calculate the included angle β between the geocenter-satellite-opposite satellite vector, and the formula is as follows:

[0046] β = acos(AO × AB / |AO| * |AB|)

[0047] AB = OB - AO = [r x_g -r x ; r y_g -r y ; r z_g -r z

[0048] In the formula, AO represents the satellite geocenter vector, AB represents the vector between the satellite and the opposite satellite, and OB represents the opposite satellite geocenter vector;

[0049] Step S5.2: Calculate the minimum included angle α of laser link visibility, and the calculation formula is as follows:

[0050] ​α = asin[(R 地 + ΔR) / |AO|]

[0051] where R 地 is the radius of the Earth, and ΔR represents the height of the Earth's atmosphere;

[0052] Step S5.3: Calculate the time interval of the laser inter-satellite link arc segment. When β > α, the laser link establishment condition is satisfied, and record the start time of the laser inter-satellite link arc segment. When β < α, the laser link establishment condition is not satisfied, and record the end time of the laser inter-satellite link arc segment;

[0053] Step S5.4: Compare the communication time interval of the DPT site with the time interval of the laser inter-satellite link arc segment, and determine whether there is a repetition in their time intervals. If so, it means that the DPT link and the laser inter-satellite link overlap. Preferentially use the DPT downlink, and set the DPT link and laser inter-satellite link overlap flag Flag_DGct to 1. If not, it means that the DPT link and the laser inter-satellite link do not overlap, and set the overlap flag Flag_DGct to 0.

[0054] Preferably, the said Step S6 includes: Compare the time interval of the laser inter-satellite link arc segment with the operation time interval of the data relay microwave link, and determine whether there is a repetition in the time interval of the laser inter-satellite link arc segment and the operation time interval of the data relay microwave link. If so, the laser inter-satellite link and the data relay microwave link overlap. Preferentially use the data relay microwave link, and set the data relay microwave link and laser inter-satellite link overlap flag Flag_ZGct to 1. If not, set the overlap flag Flag_ZGct to 0.

[0055] Preferably, if the on-orbit satellite remote sensing data downlink channels satisfy the remote sensing data downlink conditions at a certain moment, control is carried out according to the on-board priority control strategy principle. The said priority control strategy includes: DPT link > data relay microwave link > inter-satellite laser link, DPT link > inter-satellite laser link > data relay microwave link, data relay microwave link > DPT link > inter-satellite laser link, data relay microwave link > inter-satellite laser link > DPT link, inter-satellite laser link > DPT link > data relay microwave link, inter-satellite laser link > data relay microwave link > DPT link, and the corresponding priority order identifiers are 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6 respectively;

[0056] where the initial default on-board priority control strategy is DPT link > data relay microwave link > inter-satellite laser link;

[0057] The downlink working progress identifiers of the corresponding channels include the DPT link identifier 0XAB, the data relay microwave link identifier 0XAC, and the inter-satellite laser link identifier 0XAD.

[0058] A remote sensing data multi-channel downlink control optimization system based on orbit recursion provided by the present invention includes: The on-orbit satellite remote sensing data downlink channels include an X-band delay link, i.e., a DPT link, a data relay microwave link, and an inter-satellite laser link;

[0059] The optimization system module includes:

[0060] Module M1: Obtain the initial orbit parameters of the satellite itself, perform orbit recursion according to the initial orbit parameters of the satellite itself, calculate the position vector parameters of the satellite itself and the elevation angle between the satellite itself and the DPT site;

[0061] Module M2: Obtain the initial orbit value of the laser receiving satellite, i.e., the other satellite, recursively calculate the orbit of the other satellite, and obtain the position vector parameters of the other satellite;

[0062] Module M3: Extract the information of the data relay microwave link task operation table, obtain the operation time interval of the data relay microwave link, and maintain the data relay microwave link task operation table;

[0063] Module M4: Through the elevation angle between the satellite itself and the DPT site and the operation time interval of the data relay microwave link, perform strategy optimization control after the overlap of the DPT link and the data relay microwave link arc segments;

[0064] Module M5: Calculate the time interval of the laser inter-satellite link arc segment according to the position vector parameters of the other satellite, and perform strategy optimization control after the overlap of the DPT link and the laser inter-satellite link arc segments;

[0065] Module M6: Perform strategy optimization control after the overlap of the laser inter-satellite link and the data relay microwave link.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] 1. The remote sensing data autonomous control downlink strategy optimization method based on orbit recursion provided by the present invention can independently judge the link establishment conditions and independently select channels for remote sensing data downlink.

[0068] 2. The present invention formulates a priority control strategy for overlapping arc segments and independently completes shielding and downlink. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more apparent:

[0070] Figure 1 It is a schematic flow chart of the working method of the present invention;

[0071] Figure 2 It is a schematic main flow chart of link establishment in the present invention. Detailed Embodiment

[0072] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0073] The downlink channel of on-orbit satellite remote sensing data in the present invention includes an X-band delay link, that is, a DPT link, a data transmission relay microwave link, and an inter-satellite laser link.

[0074] Embodiment 1

[0075] According to an optimization method for multi-channel downlink control of remote sensing data based on orbit recursion provided by the present invention, as Figure 1 shown, it includes:

[0076] Step S1: Obtain the initial orbit parameters of the satellite itself, and perform orbit recursion based on the initial orbit parameters of the satellite itself to calculate the position vector parameters of the satellite itself and the elevation angle between the satellite itself and the DPT site. The initial orbit parameters of the satellite itself include the true anomaly of the orbit, the mean anomaly of the orbit, the eccentricity of the orbit, the semi-major axis of the orbit, the right ascension of the ascending node of the orbit, the inclination of the orbit, and the argument of perigee of the orbit. The step S1 includes:

[0077] Step S1.1: Calculate the position vector parameters of the satellite, and the formula is as follows:

[0078]

[0079] In the formula, r x , r y , r z respectively represent the three-axis components of the position vector r in the J2000.0 inertial coordinate system, R z (·), R x (·) represent matrix functions, Ω s represents the right ascension of the ascending node of the orbit, i s represents the inclination of the orbit, ω s represents the argument of perigee of the orbit, r s represents the distance between the satellite itself and the earth's center, f s represents the true anomaly of the orbit, M s represents the mean anomaly of the orbit, e s represents the eccentricity of the orbit, a s represents the semi-major axis of the orbit. Among them, the formulas of the matrix functions are as follows:

[0080]

[0081] Step S1.2: Calculate the position vector of the DPT station. The calculation formula is as follows:

[0082] Sλ = S Gt + λ s

[0083]

[0084] In the formula, S λ represents the local sidereal hour angle, S Gt is the Greenwich sidereal time, λ s is the geographical longitude, is the geocentric latitude, R cs is the geocentric distance. x sta , y sta , z sta respectively represent the position vector of the DPT station.

[0085] Step S1.3: Calculate the elevation angle between the satellite and the DPT station. The calculation formula is as follows:

[0086]

[0087] a = (r x - x sta) / ρ; b = (r y - y sta ) / ρ; c = (r z - z sta ) / ρ

[0088]

[0089] In the formula, ρ represents the distance between the satellite and the DPT station, a, b, and c represent intermediate variables, h w represents the elevation angle of the satellite relative to the ground station, that is, the elevation angle between the satellite and the DPT station.

[0090] Step S2: Obtain the initial orbit of the laser receiving satellite, that is, the other satellite, and recursively calculate the orbit of the other satellite to obtain the position vector parameters of the other satellite. The step S2 includes:

[0091] Step S2.1: Obtain the initial orbit of the other satellite. The method of obtaining the initial orbit of the other satellite includes sending it to the navigation subsystem through the Beidou short message forward link, and the navigation subsystem sends it to the on-board computer, or obtaining it by the ground measurement and control station through the method of uploading command parameters.

[0092] Step S2.2: Calculate the position vector of the other satellite. The formula is as follows:

[0093]

[0094] Among them, r x_g , ry_g , r z_g respectively represent the three-axis components of the target satellite position vector r s_g in the J2000.0 inertial coordinate system. Rz(·) and Rx(·) are matrix functions, and a s_g is the semi-major axis of the target satellite orbit, and e s_g is the eccentricity of the target satellite orbit, and M s_g is the mean anomaly of the target satellite orbit, and Ω s_g is the right ascension of the ascending node of the target satellite orbit, and i s_g is the inclination of the target satellite orbit, and ω s_g is the argument of perigee of the target satellite orbit. All of them are the initial orbit parameters of the target satellite. f s_g is the true anomaly of the target satellite orbit, and r s_g is the distance between the target satellite and the geocenter.

[0095] Step S3: Extract the information of the data relay microwave link task work sheet and maintain the data relay microwave link task work sheet. The information of the data relay microwave link task work sheet includes the start time and end time of the relay task. The start time of the relay task is 6 bytes (length), the power-on duration is 2 bytes (length), and the end time is the sum of the task start time and the power-on duration, which is 6 bytes (length). The data relay microwave link task work sheet is sorted according to the task start time, and new work tasks are inserted or tasks are deleted. The maintenance of the data relay microwave link task work sheet includes sorting, updating storage, or deleting. The data relay microwave link task work sheet supports at most 40 planned task execution instructions for service instruction packets. The cumulative number of unexecuted planned tasks uploaded is not more than 40, and they can be uploaded at any time during the satellite communication arc segment. The upload time of the service instruction packets shall not conflict, that is, the start time of the next service instruction shall be more than 5 minutes later than the end time of the previous service instruction packet. If the instruction to delete all service packet upload counts is sent, all uploaded service packet instructions shall be cleared. The service packet instructions are sorted according to the start time sequence. Whenever a new uploaded service packet instruction appears, the task work is sorted and updated.

[0096] Step S4: Perform strategy optimization control after the overlap of the DPT link and the data relay microwave link arc segment through the elevation angle between this satellite and the DPT site and the information of the data relay microwave link work sheet. The steps of S4 include:

[0097] Step S4.1: Calculate the communication time interval that meets the DPT site. When the elevation angle between the satellite and the DPT site is greater than the default DPT site elevation angle ED, DPT site communication is satisfied, and record the start time of the current DPT site communication; when the elevation angle between the satellite and the DPT site is less than the default DPT site elevation angle ED, DPT site communication is not satisfied, and record the end time of the current DPT site communication to obtain the communication time interval that meets the DPT site. For example, the default DPT site elevation angle ED is 6°. When the elevation angle h w > 6°, DPT site communication is satisfied, and record the start time of DPT site communication; when the elevation angle h w < 6°, DPT site communication is not satisfied, and record the end time of DPT site communication.

[0098] Step S4.2: Compare the DPT site communication time with the information in the data transmission relay microwave link operation table to determine whether there is a duplicate time interval between the two. If so, it means that there is an overlap between the DPT link and the data transmission relay microwave link. Prefer to use DPT for downlink, delete the duplicate instruction packets in the data transmission relay microwave link task operation table, and set the DPT link and data transmission relay microwave link overlap flag Flag_DZct = "1"; if not, it means that there is no overlap between the DPT link and the data transmission relay microwave link, and set the overlap flag Flag_DZct = "0".

[0099] Step S5: Calculate the time interval of the laser inter-satellite link arc segment according to the position vector parameters of the other satellite, and optimize the control of the strategy after the overlap of the DPT link and the laser inter-satellite link arc segment. The step S5 includes:

[0100] Step S5.1: Calculate the included angle β between the geocenter-satellite-other satellite vector, and the formula is as follows:

[0101] O is the geocenter, OA represents the geocenter vector of the satellite, then OA = [r x ; r y ; r z ;

[0102] OB represents the geocenter vector of the other satellite, then OB = [r x_g ; r y_g ; r z_g ;

[0103] AB represents the vector between the satellite and the other satellite, AB = OB - OA, that is, [r x_g - r x 8]; r y_g - r y ; r z_g - r z ;

[0104] The vector included angle β between the geocenter, this satellite and the other satellite is β = acos(AO × AB / |AO| * |AB|).

[0105] Step S5.2: Calculate the minimum included angle α for laser link establishment visibility. The calculation formula is as follows:

[0106] α = asin[(R 地 + ΔR) / |AO|]

[0107] where R 地 is the radius of the Earth, and ΔR represents the height of the Earth's atmosphere. When β is greater than α, the laser link establishment condition is satisfied. When β is less than α, the two satellites are invisible and the laser link establishment condition is not satisfied. The threshold range of ΔR is taken as [0 - 100] km.

[0108] Step S5.3: Calculate the time interval of the laser inter-satellite link arc segment. When β > α, the laser link establishment condition is satisfied, and record the start time of the laser inter-satellite link arc segment. When β < α, the laser link establishment condition is not satisfied, and record the end time of the laser inter-satellite link arc segment.

[0109] Step S5.4: Compare the communication time interval of the DPT site with the time interval of the laser inter-satellite link arc segment, and judge whether there is a repetition in their time intervals. If so, it means that the DPT link and the laser inter-satellite link overlap. Prefer to use DPT for downlink, and set the overlap flag Flag_DGct of the DPT link and the laser inter-satellite link to "1". If not, it means that the DPT link and the laser inter-satellite link do not overlap, and set the overlap flag Flag_DGct to "0".

[0110] Step S6: Strategy optimization control after the laser inter-satellite link and the data transmission relay microwave link overlap. The said Step S6 includes: comparing the time interval of the laser inter-satellite link with the time interval of the data transmission relay microwave link. Judge whether there is a repetition between the time interval of the laser inter-satellite link arc segment and the operation table time interval of the data transmission relay microwave link. If so, the laser inter-satellite link and the data transmission relay microwave link overlap. Prefer to use the data transmission relay microwave link, and set the overlap flag Flag_ZGct of the data transmission relay microwave link and the laser inter-satellite link to "1". If not, set the overlap flag Flag_ZGct to "0".

[0111] If the downlink channels of on-orbit satellite remote sensing data meet the downlink conditions of remote sensing data at a certain moment, the initial default priority control strategy on the satellite is: DPT link > data relay microwave link > inter-satellite laser link. That is to say, after the satellite is initially launched into orbit or after software reset, restart, and software initialization operations, the default control strategy priority order from high to low is the DPT link, the data relay microwave link, and the inter-satellite laser link. When the satellite is on orbit, the priority control strategy is adjusted according to needs. Specifically, the priority control strategy and the corresponding control strategy priority identifiers are shown in Table 1. The priority order identifier set by the on-board software and the identifier during the downlink operation of the corresponding channel data include the DPT link identifier 0XAB, the data relay microwave link identifier 0XAC, and the inter-satellite laser link identifier 0XAD. The identifier during the downlink operation of the channel data is shown in Table 2:

[0112] Table 1

[0113]

[0114] Table 2

[0115]

[0116] The present invention is used for the design and optimization of the multi-channel downlink control strategy of remote sensing data, formulating priority principles, and aiming to solve the problem of arc segment overlap conflict.

[0117] Embodiment 2

[0118] The present invention also provides a multi-channel downlink control optimization system for remote sensing data based on orbit recursion. The multi-channel downlink control optimization system for remote sensing data based on orbit recursion can be implemented by executing the process steps of the multi-channel downlink control optimization method based on orbit recursion. That is, those skilled in the art can understand the multi-channel downlink control optimization method based on orbit recursion as the preferred implementation manner of the multi-channel downlink control optimization system for remote sensing data based on orbit recursion.

[0119] According to a multi-channel downlink control optimization system for remote sensing data based on orbit recursion provided by the present invention, it includes:

[0120] The downlink channels of on-orbit satellite remote sensing data include the X-band delay link, that is, the DPT link, the data relay microwave link, and the inter-satellite laser link.

[0121] The optimization system module includes:

[0122] Module M1: Obtain the initial orbit parameters of the satellite itself, and perform orbit recursion according to the initial orbit parameters of the satellite itself to calculate the position vector parameters of the satellite itself and the elevation angle between the satellite itself and the DPT station. The module M1 includes: Module M1.1: Calculate the position vector parameters of the satellite, and the formula is as follows:

[0123]

[0124] Where r x 、r y 、r z They represent the three-axis components of the position vector r in the J2000.0 inertial coordinate system, R z (·), R x (·) represents the matrix function, Ω s represents the right ascension of the orbital ascending node, i s represents the orbital inclination, ω s represents the orbital perigee argument, r s represents the distance between the planet and the center of the Earth, f s Indicates the true anomaly of the orbit, M s represents the mean anomaly of the orbit, e s represents the orbital eccentricity, a s Indicates the semi-major axis of the orbit. Module M1.2: Calculate the DPT station position vector. The calculation formula is as follows:

[0125] Sλ=S Gt +λ s

[0126]

[0127] Where S λ represents the local sidereal hour angle, S Gt is Greenwich sidereal time, λ s is the geographical longitude, is the geocentric latitude, R cs is the distance from the center of the Earth. sta 、y sta 、z sta Respectively represent the DPT station position vector. Module M1.3: Calculate the elevation angle between the satellite and the DPT station. The calculation formula is as follows:

[0128]

[0129] a=(r x -x sta) / ρ. b=(r y -y sta ) / ρ. c=(r z -z sta ) / ρ

[0130]

[0131] Where ρ represents the distance between the satellite and the DPT site, a, b, and c represent intermediate variables, and h w Indicates the elevation angle of the satellite relative to the ground station, that is, the elevation angle between the satellite and the DPT site.

[0132] Module M2: Obtain the initial orbit value of the laser receiving satellite, i.e., the other satellite, recursively calculate the orbit of the other satellite, and obtain the position vector parameters of the other satellite. The module M2 includes: Module M2.1: Obtain the initial orbit value of the other satellite. Module M2.2: Calculate the position vector of the other satellite, and the formula is as follows:

[0133]

[0134] where r x_g 、r y_g 、r z_g respectively represent the three-axis components of the position vector r s_g of the other satellite in the J2000.0 inertial coordinate system, Rz(·), Rx(·) are matrix functions, a s_g is the semi-major axis of the orbit of the other satellite, e s_g is the eccentricity of the orbit of the other satellite, M s_g is the mean anomaly of the orbit of the other satellite, Ω s_g is the right ascension of the ascending node of the orbit of the other satellite, i s_g is the inclination of the orbit of the other satellite, ω s_g is the argument of periapsis of the orbit of the other satellite, all of which are the initial orbit parameters of the other satellite, f s_g is the true anomaly of the orbit of the other satellite, r s_g is the distance between the other satellite and the geocenter. The formulas of the matrix functions are as follows:

[0135]

[0136] Module M3: Extract the information of the data relay microwave link task operation table, obtain the operation time interval of the data relay microwave link, and maintain the data relay microwave link task operation table. The information of the data relay microwave link task operation table includes the start time and end time of the relay task. The maintenance of the data relay microwave link task operation table includes sorting, updating storage or deletion.

[0137] Module M4: Based on the elevation angle between the satellite and the DPT site and the operating time interval of the data transmission relay microwave link, optimize the control strategy after the DPT link and the data transmission relay microwave link arc overlap. Module M4 includes: Module M4.1: Calculate the communication time interval that meets the DPT site. When the elevation angle between the satellite and the DPT site is greater than the default DPT site elevation angle ED, the DPT site communication is satisfied, and record the start time of the current DPT site communication. When the elevation angle between the satellite and the DPT site is less than the default DPT site elevation angle ED, the DPT site communication is not satisfied, and record the end time of the current DPT site communication to obtain the communication time interval that meets the DPT site. Module M4.2: Compare the DPT site communication time interval with the operating time interval of the data transmission relay microwave link to determine whether there is a repetition between the two time intervals. If so, it means that the DPT link and the data transmission relay microwave link overlap. Preferentially use DPT for downlink, delete the duplicate instruction packets in the data transmission relay microwave link task operation table, and set the DPT link and data transmission relay microwave link overlap flag Flag_DZct to 1. If not, it means that the DPT link and the data transmission relay microwave link do not overlap, and set the overlap flag Flag_DZct to 0.

[0138] Module M5: Calculate the time interval of the laser inter-satellite link arc according to the position vector parameters of the other satellite, and optimize the control strategy after the DPT link and the laser inter-satellite link arc overlap. The module M5 includes: Module M5.1: Calculate the included angle β between the geocenter-satellite-other satellite vectors, and the formula is as follows:

[0139] β = acos(AO × AB / |AO| * |AB|)

[0140] AB = OB - AO = [r x_g -r x ; r y_g -r y ; r z_g -r z

[0141] In the formula, AO represents the satellite geocenter vector, AB represents the vector between the satellite and the other satellite, and OB represents the other satellite geocenter vector. Module M5.2: Calculate the minimum included angle α for laser link visibility, and the calculation formula is as follows:

[0142] α = asin[(R 地 +ΔR) / |AO|]

[0143] Where, R 地$R$ is the radius of the Earth, and $\Delta R$ represents the height of the Earth's atmosphere. Module M5.3: Calculate the time interval of the laser inter-satellite link arc segment. When $\beta \gt \alpha$, the laser link establishment condition is satisfied, and the start time of the laser inter-satellite link arc segment is recorded. When $\beta \lt \alpha$, the laser link establishment condition is not satisfied, and the end time of the laser inter-satellite link arc segment is recorded. Module M5.4: Compare the communication time interval of the DPT site with the time interval of the laser inter-satellite link arc segment, and determine whether there is a repetition in the time intervals of the two. If so, it means that the DPT link and the laser inter-satellite link overlap. Prefer to download via DPT, and set the DPT link and laser inter-satellite link overlap flag Flag_DGct to 1. If not, it means that the DPT link and the laser inter-satellite link do not overlap, and set the overlap flag Flag_DGct to 0.

[0144] Module M6: Strategy optimization control after the laser inter-satellite link and the data relay microwave link overlap. The module M6 includes: comparing the time interval of the laser inter-satellite link arc segment with the operation time interval of the data relay microwave link, and determining whether there is a repetition in the time interval of the laser inter-satellite link arc segment and the operation time interval of the data relay microwave link. If so, the laser inter-satellite link and the data relay microwave link overlap. Prefer to use the data relay microwave link, and set the data relay microwave link and laser inter-satellite link overlap flag Flag_ZGct to 1. If not, set the overlap flag Flag_ZGct to 0.

[0145] If the on-orbit satellite remote sensing data downlink channel satisfies the remote sensing data downlink conditions at a certain moment, it is controlled according to the on-board priority control strategy principle. The priority control strategy includes: DPT link > data relay microwave link > inter-satellite laser link, DPT link > inter-satellite laser link > data relay microwave link, data relay microwave link > DPT link > inter-satellite laser link, data relay microwave link > inter-satellite laser link > DPT link, inter-satellite laser link > DPT link > data relay microwave link, inter-satellite laser link > data relay microwave link > DPT link. The corresponding priority order identifiers are 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6 respectively. Among them, the initial default on-board priority control strategy is DPT link > data relay microwave link > inter-satellite laser link. The identifiers for the downlink work of the corresponding channel data include the DPT link identifier 0XAB, the data relay microwave link identifier 0XAC, and the inter-satellite laser link identifier 0XAD.

[0146] Those skilled in the art know that in addition to implementing the system and its various devices, modules, and units provided by the present invention in the form of pure computer-readable program code, the method steps can be logically programmed to enable the system and its various devices, modules, and units provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc. to achieve the same functions. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a kind of hardware component, and the devices, modules, and units included therein for implementing various functions can also be regarded as the structures within the hardware component. The devices, modules, and units for implementing various functions can also be regarded as either software modules for implementing the method or structures within the hardware component.

[0147] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An optimization method for multi-channel downlink control of remote sensing data based on orbit recursion, characterized in that Including: The on-orbit satellite remote sensing data downlink channel includes an X-band delay link, namely a DPT link, a data transmission relay microwave link, and an inter-satellite laser link; The optimization method steps include: Step S1: Obtain the initial orbital parameters of the satellite itself, and perform orbital recursion according to the initial orbital parameters of the satellite itself to calculate the position vector parameters of the satellite itself and the elevation angle between the satellite itself and the DPT station; Step S2: Obtain the initial orbital value of the laser receiving satellite, that is, the other satellite, and recursively calculate the orbit of the other satellite to obtain the position vector parameters of the other satellite; Step S3: Extract the information of the data transmission relay microwave link task operation table, obtain the operation time interval of the data transmission relay microwave link, and maintain the data transmission relay microwave link task operation table; Step S4: Through the elevation angle between the satellite itself and the DPT station and the operation time interval of the data transmission relay microwave link, perform strategy optimization control after the arc segments of the DPT link and the data transmission relay microwave link overlap; Step S5: Calculate the time interval of the laser inter-satellite link arc segment according to the position vector parameters of the other satellite, and perform strategy optimization control after the arc segments of the DPT link and the laser inter-satellite link overlap; Step S6: Perform strategy optimization control after the laser inter-satellite link and the data transmission relay microwave link overlap.

2. The optimized method for multi-channel downlink control of remote sensing data based on orbit recursion according to claim 1, wherein The said Step S1 includes: Step S1.1: Calculate the satellite position vector parameters, and the formula is as follows: where r x , r y , r z respectively represent the three-axis components of the position vector r in the J2000.0 inertial coordinate system, R z (·), R x (·) represent matrix functions, Ω s represents the right ascension of the ascending node of the orbit, i s represents the orbital inclination, ω s represents the argument of perigee of the orbit, r s represents the distance between the satellite and the geocenter, f s represents the true anomaly of the orbit, M s represents the mean anomaly of the orbit, e s represents the eccentricity of the orbit, a s represents the semi-major axis of the orbit; Step S1.2: Calculate the position vector of the DPT station, and the calculation formula is as follows: Sλ = S Gt + λ s Where, S λ represents the local sidereal hour angle, S Gt is the Greenwich sidereal time, λ s is the geographical longitude, is the geocentric latitude, R cs is the geocentric distance. x sta , y sta , z sta respectively represent the position vectors of the DPT site; Step S1.3: Calculate the elevation angle between the satellite itself and the DPT station, and the calculation formula is as follows: a = (r x - x sta) ) / ρ; b = (r y - y sta ) / ρ; c = (r z - z sta ) / ρ Where ρ represents the distance between the satellite and the DPT station, a, b, and c represent intermediate variables, and h w represents the elevation angle of the satellite relative to the ground station, i.e., the elevation angle between the satellite and the DPT station.

3. The optimized method for multi-channel downlink control of remote sensing data based on orbit recurrence according to claim 1, wherein The said Step S2 includes: Step S2.1: Obtain the initial orbital value of the other satellite; Step S2.2: Calculate the position vector of the other satellite, and the formula is as follows: where r x_g , r y_g , r z_g represent the three-axis components of the position vector r s_g of the target star in the J2000.0 inertial coordinate system respectively, Rz(·) and Rx(·) are matrix functions, a s_g is the semi-major axis of the target star's orbit, e s_g is the eccentricity of the target star's orbit, M s_g is the mean anomaly of the target star's orbit, Ω s_g is the right ascension of the ascending node of the target star's orbit, i s_g is the inclination of the target star's orbit, ω s_g is the argument of periapsis of the target star's orbit, all of which are the initial orbit parameters of the target star, f s_g is the true anomaly of the target star's orbit, and r s_g is the distance between the target star and the geocenter.

4. The multi-channel downlink control optimization method for remote sensing data based on orbit recursion according to claim 2 or 3, characterized in that The formulas of the matrix functions are as follows respectively:

5. The optimized method for downlink control of multi-channel remote sensing data based on orbit recursion according to claim 1, wherein The information of the data transmission relay microwave link task operation table includes the start time and end time of the relay task; The maintenance of the data transmission relay microwave link task operation table includes sorting, updating storage or deletion.

6. The optimized method for downlink control of multi-channel remote sensing data based on orbit recurrence according to claim 1, wherein The said Step S4 includes: Step S4.1: Calculate the communication time interval that meets the DPT station. When the elevation angle between the satellite itself and the DPT station is greater than the default elevation angle ED of the DPT station, the communication with the DPT station is satisfied, and record the current start time of the DPT station communication; when the elevation angle between the satellite itself and the DPT station is less than the default elevation angle ED of the DPT station, the communication with the DPT station is not satisfied, and record the current end time of the DPT station communication to obtain the communication time interval that meets the DPT station; Step S4.2: Compare the communication time interval of the DPT station with the operation time interval of the data transmission relay microwave link to judge whether there is a repetition between the two time intervals. If so, it means that there is an overlap between the DPT link and the data transmission relay microwave link. Prefer to use DPT for downlink, delete the duplicate instruction packets in the data transmission relay microwave link task operation table, and set the overlap flag Flag_DZct between the DPT link and the data transmission relay microwave link to 1; if not, it means that there is no overlap between the DPT link and the data transmission relay microwave link, and set the overlap flag Flag_DZct to 0.

7. The optimized method for multi-channel downlink control of remote sensing data based on orbit recursion according to claim 1, characterized in that The said Step S5 includes: Step S5.1: Calculate the vector included angle β between the geocenter-satellite itself-the other satellite, and the formula is as follows: β = acos(AO × AB / |AO| * |AB|) AB = OB - AO = [r x_g -r x ; r y_g -r y ; r z_g -r z ​ Wherein, AO represents the geocentric vector of the local satellite, AB represents the vector between the local satellite and the other satellite, and OB represents the geocentric vector of the other satellite; Step S5.2: Calculate the minimum angle α of laser link establishment visibility, and the calculation formula is as follows: α = asin[(R 地 + ΔR) / |AO|] where R 地 is the radius of the Earth, and ΔR represents the height of the Earth's atmosphere; Step S5.3: Calculate the time interval of the laser inter-satellite link arc segment. When β > α, the laser link establishment condition is met, and record the start time of the laser inter-satellite link arc segment. When β < α, the laser link establishment condition is not met, and record the end time of the laser inter-satellite link arc segment; Step S5.4: Compare the communication time interval of the DPT site with the time interval of the laser inter-satellite link arc segment, and determine whether there is a repetition between the two time intervals. If so, it means that the DPT link and the laser inter-satellite link overlap, and give priority to DPT downlink, and set the overlap flag Flag_DGct of the DPT link and the laser inter-satellite link to 1; if not, it means that the DPT link and the laser inter-satellite link do not overlap, and set the overlap flag Flag_DGct to 0.

8. The optimized method for downlink control of multi-channel remote sensing data based on orbit recurrence according to claim 1, wherein The said step S6 includes: comparing the time interval of the laser inter-satellite link arc segment with the operation time interval of the data relay microwave link, and determining whether there is a repetition between the time interval of the laser inter-satellite link arc segment and the operation time interval of the data relay microwave link. If so, the laser inter-satellite link and the data relay microwave link overlap, and give priority to the data relay microwave link, and set the overlap flag Flag_ZGct of the data relay microwave link and the laser inter-satellite link to 1; if not, set the overlap flag Flag_ZGct to 0.

9. The optimized method for multi-channel downlink control of remote sensing data based on orbital recursion according to claim 1, wherein, If the remote sensing data downlink channels of the on-orbit satellite meet the remote sensing data downlink conditions at a certain moment, control is carried out in accordance with the on-board priority control strategy principle. The said priority control strategy includes: DPT link > data relay microwave link > inter-satellite laser link, DPT link > inter-satellite laser link > data relay microwave link, data relay microwave link > DPT link > inter-satellite laser link, data relay microwave link > inter-satellite laser link > DPT link, inter-satellite laser link > DPT link > data relay microwave link, inter-satellite laser link > data relay microwave link > DPT link, and the corresponding priority order identifiers are 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6 respectively; Among them, the initial default on-board priority control strategy is DPT link > data relay microwave link > inter-satellite laser link; The identification of the corresponding channel data downlink operation includes the DPT link identification 0XAB, the data relay microwave link identification 0XAC, and the inter-satellite laser link identification 0XAD.

10. A multi-channel downlink control optimization system for remote sensing data based on orbit recurrence, characterized in that, Including: The remote sensing data downlink channels of the on-orbit satellite include the X-band delay link, that is, the DPT link, the data relay microwave link, and the inter-satellite laser link; The optimization system module includes: Module M1: Obtain the initial orbit parameters of the local satellite, and perform orbit recursion according to the initial orbit parameters of the local satellite, and calculate the position vector parameters of the local satellite and the elevation angle between the local satellite and the DPT site; Module M2: Obtain the initial orbit value of the laser receiving satellite, that is, the other satellite, and recursively calculate the orbit of the other satellite to obtain the position vector parameters of the other satellite; Module M3: Extract the information of the data transmission relay microwave link task operation table, obtain the operation time interval of the data transmission relay microwave link, and maintain the data transmission relay microwave link task operation table; Module M4: Through the elevation angle between the satellite and the DPT site and the operation time interval of the data transmission relay microwave link, perform the strategy optimization control after the DPT link and the data transmission relay microwave link arc segments overlap; Module M5: Calculate the time interval of the laser inter-satellite link arc segment according to the position vector parameters of the other satellite, and perform the strategy optimization control after the DPT link and the laser inter-satellite link arc segments overlap; Module M6: Strategy optimization control after the laser inter-satellite link and the data transmission relay microwave link overlap.

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