A method for producing a shipborne mobile receiving station remote sensing satellite spot beam data transmission task

Abstract

This invention provides a method for creating a point-beam data transmission mission for a shipborne mobile receiving station to remote sensing satellites. The method includes: using the acquired approximate position and orbital element information of the shipborne receiving station, calculating a set of all approximate visible time windows for the entire day; then using this set to determine the approximate time window for the target data transmission mission; based on the approximate time window, sequentially calculating the ship's geocentric latitude, ship's travel distance, and spherical arc length; determining, based on the spherical arc length, whether the ship's course change exceeds a preset threshold; if so, performing segmented ship position prediction; otherwise, performing direct ship position prediction to obtain a precise predicted ship position; expanding the approximate time window based on the precise predicted ship position to obtain a precise time window; and then using the precise time window and the precise predicted ship position to construct the point-beam data transmission mission. This invention achieves precise planning of the satellite data transmission mission and ensures that the shipborne station antenna points towards the satellite to form a two-way closed link.

Description

Technical Field

[0001] This invention relates to the field of remote sensing satellite spot beam data transmission technology, and in particular to a method for creating a remote sensing satellite spot beam data transmission mission for a shipborne mobile receiving station. Background Technology

[0002] Remote sensing satellites transmit spatial information detected by their payloads back to Earth via data transmission antennas in the data transmission subsystem. Data transmission antennas can be broadly categorized into two types: global beams and spot beams. Global beams have a very wide beamwidth, covering a large area of ​​the Earth, thus having less stringent pointing requirements and being easier to acquire and maintain links; however, they have low gain, dispersed energy, and are susceptible to interference, resulting in lower data transmission rates. Spot beams have a very narrow beamwidth, covering only a small ground area, but their energy is highly concentrated, resulting in extremely high data transmission rates, while requiring extremely precise pointing.

[0003] Earth-to-ground data transmission from remote sensing satellite point-beam data transmission antennas requires real-time calculation of the antenna's pointing direction using the satellite platform's real-time position and the Earth receiving station's position to ensure the antenna is always precisely pointed at the Earth receiving antenna. For fixed Earth receiving stations: their position is constant and pre-stored in the satellite platform; by predicting satellite orbits, the time window for future satellite overpasses can be easily calculated, and data transmission tasks can be planned. For shipborne mobile receiving stations: the precise position of the mobile station needs to be uploaded to the satellite platform before satellite data transmission is activated. Since the ship is constantly in motion, satellite data transmission task planning depends on the position of the shipborne mobile receiving station, while the mobile station's position calculation requires the satellite data transmission task timing; the two are coupled. Therefore, decoupling becomes crucial.

[0004] In summary, existing technologies have the following drawbacks in shipborne mobile station scenarios: 1) Continuously changing station positions: Fixed station algorithms assume a constant station position, and direct application of this leads to deviations between window calculations and target pointing. 2) Task and station position coupling: Task time window calculations require station positions; accurate station position calculations or predictions require specific target times; this prevents the sequential planning of tasks as with fixed stations, creating a coupling problem. 3) Low spot beam tolerance: Narrow spot beams amplify station position or time errors into pointing errors, easily causing acquisition failures, link maintenance difficulties, and decreased throughput. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the purpose of this invention is to provide a method for creating a remote sensing satellite point beam data transmission mission for a shipborne mobile receiving station. This method solves the coupling problem between remote sensing satellite data transmission mission planning and accurate ship position calculation during navigation, completes the accurate planning of the satellite data transmission mission, and enables the shipborne station antenna to point towards the satellite to form a two-way closed link.

[0006] To achieve the above objectives, the present invention provides the following solution: a method for creating a remote sensing satellite point beam data transmission mission for a shipborne mobile receiving station, comprising: Using the obtained rough location and orbital element information of the shipborne receiving station, calculate the set of all rough visible time windows for the whole day, and then use the set of rough visible time windows to determine the rough time window of the target data transmission task; Based on the aforementioned coarse time window, the ship's geocentric latitude, the ship's sailing distance, and the spherical arc length are calculated sequentially. Based on the spherical arc length, it is determined whether the change in the ship's course exceeds a preset threshold for the number of changes. If so, the ship's position is predicted in segments; otherwise, the ship's position is predicted directly to obtain an accurate predicted position. Based on the accurately predicted ship position, the coarse time window is expanded to obtain an accurate time window. Then, using the accurate time window and the accurately predicted ship position, a point beam data transmission task is constructed.

[0007] Optionally, using the acquired approximate location and orbital element information of the shipborne receiving station, a set of all approximate visible time windows for the entire day is calculated, and then the approximate time window for the target data transmission task is determined using the set of approximate visible time windows, including: Based on the navigation plan of the ship where the shipborne mobile receiving station is located, select a certain time on the date of the data transmission mission to obtain the approximate location of the shipborne receiving station. Based on the approximate location of the shipborne receiving station and the instantaneous root count or two-line root count information of the satellite, calculate the set of all approximate visible time windows of the shipborne receiving station to the satellite for the entire day of the date at the given moment; Based on the detection requirements, the approximate time window for the target data transmission task of the shipborne receiving station is determined using the aforementioned set of approximate visible time windows.

[0008] Optionally, based on the coarse time window, the ship's geocentric latitude, the ship's sailing distance, and the spherical arc length are calculated sequentially, including: The ship's geodetic longitude and geodetic latitude are obtained using the shipborne global positioning system to obtain the ship's current position coordinates, and the geodetic latitude of the ship's current position coordinates is converted into geocentric latitude. The time interval from the current moment to the middle of the approximate time window is set as the sailing time, and the sailing distance traveled by the ship from the current position is calculated using the sailing time and sailing speed. Obtain the geocentric distance of the current ship position, and calculate the spherical arc length using the geocentric distance and the sailing distance.

[0009] Optionally, based on the spherical arc length, it is determined whether the change in the ship's course exceeds a preset threshold for the number of changes. If so, segmented prediction of the ship's position is performed; otherwise, direct prediction of the ship's position is performed to obtain an accurate predicted position, including: Based on the spherical arc length, determine whether the change in the ship's course exceeds a preset threshold for the number of changes. If so, divide the sailing time into multiple time intervals according to the time of course change in the ship's sailing plan. The ship's predicted position is calculated within each time interval, and the current ship's predicted position is used as the starting position of the next time interval to calculate the predicted position for all time intervals. The ship's predicted position in the last time interval is used as the accurate predicted position of the shipborne mobile receiving station at the middle of the coarse time window. Determine whether the ship's course change exceeds a preset threshold number of changes. If not, use the relevant features of a spherical triangle to calculate the geodetic latitude and longitude of the predicted ship position and output the accurate predicted ship position.

[0010] Optionally, based on the accurately predicted ship position, the coarse time window is expanded to obtain an accurate time window. Then, using the accurate time window and the accurately predicted ship position, a point-beam data transmission task is constructed, including: The start and end times of the data transmission task's rough window are each extended by 10 minutes to obtain an extended time window. The orbital position within the extended time window is obtained by using the latest instantaneous roots or two rows of roots from the remote sensing satellite and the satellite orbit prediction algorithm. Using the precise prediction of ship position and satellite time window calculation method, the precise time window for data transmission mission is obtained. Then, using the precise time window for data transmission mission and the precise prediction of ship position, satellite commands are generated, and the satellite commands are sent to the telemetry and control department and uploaded to the satellite platform. According to the satellite command, determine whether the satellite has flown into the precise time window of the data transmission mission. If so, activate the satellite data transmission system, use the data transmission antenna to rotate in real time to point to the precisely predicted ship position of the shipborne mobile receiving station, and point the shipborne mobile receiving station antenna to the satellite to establish a satellite-to-ground link, receive remote sensing satellite data, and complete the construction of the spot beam data transmission mission.

[0011] This invention discloses the following technical effects by providing a method for creating remote sensing satellite spot beam data transmission missions for shipborne mobile receiving stations: 1. Clear decoupling effect: By using the link of "coarse window, intermediate time, precise ship position, and precise window", the coupling of task formulation depending on ship position and ship position calculation depending on task time is decomposed into a problem that can be solved sequentially, forming an implementable process.

[0012] 2. Adapting to high point beam directivity requirements: Point beams are narrow, have high gain, and require high alignment. This method improves alignment and timing matching by using precise station prediction and precise window recalculation, thus supporting high-speed data transmission.

[0013] 3. Comply with engineering operation rules: Maintain the operation mode of setting tasks one day or several days in advance, while taking into account the segmented calculation of course changes, and closely resembling the actual navigation of the ship.

[0014] 4. Does not affect navigation: It enables precise planning and transmission without affecting the normal navigation of the ship, making it suitable for research vessels or ocean-going missions.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the method flow provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the predicted location calculation for a shipborne mobile receiving station provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the accurate location prediction process for a shipborne mobile receiving station provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 like Figure 1 As shown, this invention provides a method for creating a remote sensing satellite spot beam data transmission mission for a shipborne mobile receiving station, comprising: Step 1: Using the acquired approximate location and orbital element information of the shipborne receiving station, calculate the set of all approximate visible time windows for the entire day, and then use the set of approximate visible time windows to determine the approximate time window for the target data transmission task; Step 1 includes: Based on the navigation plan of the ship where the shipborne mobile receiving station is located, a certain moment on the date of the proposed data transmission mission is selected to obtain the approximate location of the shipborne receiving station; based on the approximate location of the shipborne receiving station and the satellite instantaneous root count or two-line root count information, the set of all approximate visible time windows of the shipborne receiving station on the date of the specified moment is calculated; based on the detection requirements, the approximate time window of the target data transmission mission of the shipborne receiving station is determined using the set of approximate visible time windows.

[0021] Step 1 in detail: Satellite approximate time window calculation: Based on the navigation plan of the ship where the shipborne mobile receiving station is located, the department that formulates a satellite data transmission mission selects a specific time on the date when the data transmission mission is to be completed. The approximate location of the shipborne receiving station. Based on the approximate location of the shipborne receiving station and information such as the instantaneous root count or two-line root count of the satellite, the following is calculated: The shipborne receiving station's approximate time windows visible to the satellite throughout the day of the given date.

[0022] The approximate time window for data transmission tasks was determined as follows: Taking into account the user's detection needs, the department responsible for developing a satellite data transmission task determined the approximate time window for the shipborne receiving station's data transmission tasks as (…). , ).

[0023] in, This is the start time of a rough time window. This is the end time of a rough time window.

[0024] Step 2, as follows Figure 3 As shown, based on the coarse time window, the ship's geocentric latitude, the ship's sailing distance, and the spherical arc length are calculated sequentially; step 2 includes: The ship's geodetic longitude and latitude are obtained using the ship's onboard global positioning system to obtain the ship's current position coordinates, and the geodetic latitude of the current position coordinates is converted into geocentric latitude; the time interval from the current time to the middle of a coarse time window is set as the sailing time, and the sailing distance traveled by the ship from the current position is calculated using the sailing time and sailing speed; the geocentric distance of the current ship position is obtained, and the spherical arc length is calculated using the geocentric distance and the sailing distance.

[0025] Step 2 in detail: Ship position geocentric latitude calculation: The ship's position coordinates, obtained using an onboard global positioning system (such as BeiDou and GPS), are generally geodetic longitude and latitude. Local calculations on the Earth's surface can approximate the standard ellipsoid as a standard sphere. Let's assume the current time... The ship's position coordinates are ( , ), the geodetic latitude of the ship's position coordinates Convert to geocentric latitude .

[0026] Ship distance calculation: Calculating ship distance requires knowing the ship's speed and calculating the travel time. The ship starts from the current time... Sailing to the middle of a rough time window time interval This refers to the sailing time. The sailing speed can be obtained from the bridge. Using these two parameters, the ship's speed from its current position can be calculated. Sailing to a future location Distance at time .

[0027] Spherical arc length calculation: To facilitate subsequent spherical calculations, the travel distance needs to be converted into a spherical arc length. First, the radius of the great circle containing the traveled spherical arc length needs to be calculated, and then the spherical arc length is calculated. The distance from the Earth's center to the current ship's location is approximated as the radius of the great circle, using the Earth's semi-major axis. Earth's minor axis And ship position latitude Calculate the current position Earth's distance Using sailing distance and the radius of the great circle of the sphere (i.e., the distance from the Earth's center) The spherical arc length corresponding to the ship's sailing distance can be calculated. .

[0028] Step 3, as follows Figure 2 , Figure 3 As shown, based on the spherical arc length, it is determined whether the ship's course change exceeds a preset threshold number of changes. If so, segmented ship position prediction is performed; otherwise, direct ship position prediction is performed to obtain an accurate predicted ship position. Step 3 includes: Based on the spherical arc length, it is determined whether the ship's course change exceeds a preset threshold for the number of changes. If so, the voyage time is divided into multiple time intervals according to the course change time in the ship's voyage plan. Within each time interval, the predicted ship position is calculated, and the current predicted ship position is used as the starting position for the next time interval. The predicted ship position for all time intervals is then calculated, and the predicted ship position for the last time interval is used as the precise predicted ship position for the shipborne mobile receiving station at the midpoint of the approximate time window. Specifically: If the shipborne mobile receiving station arrives from the current time Sailing to the middle of a rough time window During the process, the course changed Next, it is necessary to adjust the course according to the time of course change in the ship's navigation plan. , ) divided into +1 time intervals, with the predicted fixed position calculated in each time interval serving as the starting position for the next time interval. Depending on the heading angle, follow the above process... Once all calculations for the +1 time interval are completed, the predicted point for the last time interval will be the precise location of the shipborne mobile receiving station at the midpoint of the approximate time window. The system determines whether the ship's course change exceeds a preset threshold. If not, it calculates the geodetic latitude and longitude of the predicted ship position using the relevant features of a spherical triangle, outputting the accurate predicted ship position. Specifically: Geodetic latitude calculation of predicted location: To obtain the predicted points The latitude of the earth needs to be determined using spherical triangles. This is achieved through the relevant characteristics. (Known) edge , The angle between the two sides The predicted point can be obtained using the cosine formula for a spherical triangle. geocentric latitude Then, the geocentric latitude of the predicted point is determined. Converted to Earth Latitude .

[0029] Calculation of geodetic longitude of budget points: Given a spherical triangle of and edge , The current position is calculated using the sine formula for a spherical triangle. and predicted points Longitude difference Combined with the ship's heading angle To calculate the geodetic longitude of the predicted location .

[0030] Step 4: Based on the accurately predicted ship position, expand the coarse time window to obtain a precise time window, and then use the precise time window and the accurately predicted ship position to construct a spot beam data transmission task. Step 4 includes: The data transmission task rough window ( , The start and end times of the window are each extended by 10 minutes to obtain the extended time window. -10, +10), and using the latest instantaneous roots or two-row roots of remote sensing satellites and satellite orbit prediction algorithms, the orbit position within the extended time window is obtained.

[0031] Using the aforementioned method for accurately predicting ship position and calculating satellite time windows, the precise time window for the data transmission mission is obtained. , Then, using the precise time window of the data transmission task and the precise predicted ship position, satellite commands are generated, and the satellite commands are sent to the telemetry and control department and uploaded to the satellite platform.

[0032] According to the satellite command, determine whether the satellite has flown into the precise time window of the data transmission mission. If so, activate the satellite data transmission system, use the data transmission antenna to rotate in real time to point to the precisely predicted ship position of the shipborne mobile receiving station, and point the shipborne mobile receiving station antenna to the satellite to establish a satellite-to-ground link, receive remote sensing satellite data, and complete the construction of the spot beam data transmission mission.

[0033] Example 2 Assume the current location of the shipborne mobile receiving station: Assume the current time is 02:09:00 on November 26, XXXX, the ship's longitude is 120.9600°, and the ship's latitude is the approximate latitude value of the shipborne mobile receiving station -61.1106°.

[0034] 1. Calculation of satellite coarse time window: Using the known number of two rows of roots from a certain remote sensing satellite and the approximate location of the shipborne mobile receiving station, calculate the approximate time window for November 25th, XXXX. The approximate time window is shown in Table 1 below.

[0035] Table 1. Approximate Time Window Table for a Certain Satellite

[0036] 2. Determining the approximate time window for data transmission tasks Taking into account the business needs of relevant users, the data transmission task formulation department determined the satellite orbit number for the shipborne mobile receiving station data transmission task to be 21129, the approximate start time of the time window to be XXXX / 11 / 27T19:52:03, the end time to be XXXX / 11 / 27T20:02:21, and the window duration to be 618.120 seconds.

[0037] 3. Precise location prediction of shipborne mobile receiving stations a) Calculation of ship's geocentric latitude The ship's position at 02:09:00 on November 26, XXXX is 120.9600° longitude, -61.1106° latitude, 10.2 knots speed, and 267 degrees heading. The calculated geocentric latitude of the ship is -60.9475°.

[0038] b) Calculation of sailing distance Based on the current time T02:09:00 on November 26, XXXX and the midpoint of the approximate time window, 19:57:12 on November 27, XXXX, the time required for the shipborne mobile receiving station to travel to the midpoint of the approximate time window is calculated to be 41.8033 hours.

[0039] Based on a speed of 10.2 knots and a sailing time of 41.8033 hours, the sailing distance of the shipborne mobile receiving station is 789.6817 kilometers.

[0040] c) Calculation of spherical arc length Based on the geodetic latitude of the ship's current position, the radius of the great circle can be calculated to be 6361.7758 km. Based on this radius and the sailing distance, the arc length of the sphere can be calculated to be 7.1121°.

[0041] d) Calculation of geodetic latitude of predicted location Based on the current ship position's geocentric latitude and heading angle, the geocentric latitude of the predicted point is calculated to be -60.5280°, and the geodetic latitude of the predicted point is calculated to be -60.6925°.

[0042] e) Calculation of geodetic longitude of the predicted location Based on the heading angle, the geocentric latitude of the predicted point, and the spherical arc length, the geodetic latitude of the predicted point is calculated to be 106.4054°.

[0043] 4. Precise time window calculation for data transmission tasks The start and end times of the previously calculated coarse time window for a satellite are each extended by 10 minutes; this is called the extended time window. The precise time window for the data transmission mission is then calculated within the extended time window using the satellite's latest orbital elements and predicted geostationary position. A comparison of the various time windows is shown in Table 2 below. As can be seen from the table, the precise time window is shifted forward overall compared to the coarse time window.

[0044] Table 2 Comparison of Time Windows for a Certain Satellite

[0045] 5. Upload information related to data transmission tasks The precise time window for data transmission and the accurate prediction of the shipborne mobile receiving station's location are used to generate satellite commands, which are then uploaded to the satellite platform by the satellite telemetry and control department.

[0046] Therefore, this invention provides a method for creating a remote sensing satellite point beam data transmission mission for a shipborne mobile receiving station, which solves the coupling problem between remote sensing satellite data transmission mission planning and accurate ship position calculation during navigation. It completes the accurate planning of the satellite data transmission mission and enables the shipborne station antenna to point towards the satellite to form a two-way closed link.

[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0048] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for producing a point beam data transmission task of a remote sensing satellite by a mobile receiving station on a ship, characterized in that, The application relates to a method for determining a target satellite data transmission task based on a rough position of a shipborne receiving station and orbit root number information, comprising the following steps: calculating a rough visible time window set of all day by using the acquired rough position of the shipborne receiving station and the orbit root number information, and then determining a rough time window of the target data transmission task by using the rough visible time window set; calculating a ship position geocentric latitude, a ship sailing distance and a spherical arc length based on the rough time window; judging whether the ship course change is greater than a preset change frequency threshold based on the spherical arc length, and if yes, performing ship position segmented prediction, and if no, performing ship position direct prediction to obtain an accurate predicted ship position; expanding the rough time window to obtain an accurate time window by using the accurate predicted ship position, and then constructing a point-beam data transmission task by using the accurate time window and the accurate predicted ship position.

2. The method according to claim 1, wherein the method is characterized in that, The application relates to a method for determining a target satellite data transmission task based on a rough position of a shipborne receiving station and orbit root number information, comprising the following steps: selecting a certain moment of a date on which a data transmission task is to be made according to a sailing plan of a ship on which the shipborne mobile receiving station is located to obtain a rough position of the shipborne receiving station; calculating a rough visible time window set of all day of the date on which the certain moment is located according to the rough position of the shipborne receiving station and satellite instantaneous root number or two-line root number information; determining a rough time window of the target data transmission task of the shipborne receiving station by using the rough visible time window set according to detection requirements.

3. The method according to claim 2, wherein, The application relates to a method for determining a target satellite data transmission task based on a rough position of a shipborne receiving station and orbit root number information, comprising the following steps: obtaining a current ship position coordinate by using a shipborne global positioning system to acquire a geodetic longitude and a geodetic latitude of a ship during sailing, and converting the geodetic latitude of the current ship position coordinate into a geocentric latitude; setting a time interval from the current moment to a middle moment of the rough time window as a sailing time, and calculating a sailing distance of the ship from the current position by using the sailing time and a sailing speed; obtaining a geocentric distance of the current ship position, and calculating a spherical arc length by using the geocentric distance and the sailing distance.

4. The method according to claim 3, wherein, The application relates to a method for determining a target satellite data transmission task based on a rough position of a shipborne receiving station and orbit root number information, comprising the following steps: judging whether the ship course change is greater than a preset change frequency threshold based on the spherical arc length, and if yes, performing ship position segmented prediction, and if no, performing ship position direct prediction to obtain an accurate predicted ship position; judging whether the ship course change is greater than a preset change frequency threshold based on the spherical arc length, and if yes, dividing the sailing time into a plurality of time intervals according to a course changing moment in the sailing plan; calculating a ship predicted point position in each time interval, taking the current ship predicted point position as a starting position of the next time interval to calculate all the time interval predicted point positions, and taking the ship predicted point position of the last time interval as an accurate predicted ship position of the shipborne mobile receiving station at the middle moment of the rough time window; judging whether the ship course change is greater than a preset change frequencythreshold, and if no, calculating a ship predicted point position geodetic latitude and a predicted point position geodetic longitude by using the related features of a spherical triangle, and outputting the accurate predicted ship position.

5. The method according to claim 4, wherein, According to the accurate predicted ship position, the rough time window is extended to obtain an accurate time window, and then the accurate time window and the accurate predicted ship position are used to construct a point beam data transmission task, comprising: The start time and the end time of the data transmission task rough window are each extended by 10 minutes to obtain an extended time window, and the latest instantaneous root number or two-row root number of the remote sensing satellite and a satellite orbit prediction algorithm are used to obtain the orbit position in the extended time window; The data transmission task accurate time window is obtained by using the accurate predicted ship position and a satellite time window calculation method, and then the data transmission task accurate time window and the accurate predicted ship position are used to make satellite instructions, the satellite instructions are sent to a measurement and control department and uploaded to a satellite platform; According to the satellite instructions, it is judged whether the satellite flies to the data transmission task accurate time window, if yes, the satellite data transmission system is started, the data transmission antenna is used to rotate and point to the accurate predicted ship position of the ship-borne mobile receiving station in real time, and the ship-borne mobile receiving station antenna is pointed to the satellite to establish a satellite-ground link, receive remote sensing satellite data, and complete the construction of the point beam data transmission task.

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