Collision Warning Method for Spacecraft

Abstract

The present invention discloses a method for collision warning of a spacecraft. Among them, this method relates to the field of spacecraft collision warning, and includes: obtaining the first orbit data of the spacecraft and the second orbit data of multiple space targets; performing epoch and perigee-apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets; searching for a target time interval with potential rendezvous risks based on the first orbit data and the second orbit data of the candidate space targets; determining the minimum relative distance between the spacecraft and the candidate space targets within the target time interval, and determining the collision warning result of the spacecraft and the candidate space targets based on the minimum relative distance. The present invention can reduce the computational amount of collision warning and improve the computational efficiency of spacecraft collision warning while ensuring no missed warnings.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft collision warning, and more particularly, to a method for warning of spacecraft collisions. Background Art

[0002] In recent years, the space technology has made a series of great progress, the threshold for entering and using space has been greatly reduced, the number of space launches and space targets has increased sharply, posing a serious threat to the safety of space flight and space activities. The relative speed between a spacecraft and a space target ranges from several kilometers per second to more than ten kilometers per second. A space debris with a diameter of 1 cm may cause catastrophic damage to the spacecraft. For space debris with a diameter greater than 10 cm, the spacecraft must perform an evasive maneuver to ensure its safe operation in orbit. Therefore, it is necessary to use real-time updated orbital data to conduct routine proximity analysis and collision warning for the spacecraft, early warning of high-risk rendezvous events, and providing a decision-making basis for the spacecraft to perform evasive maneuvers.

[0003] Currently, the number of cataloged on-orbit space targets announced has exceeded 29,000. When a spacecraft conducts a collision warning, if the orbital prediction is calculated for each space target at each epoch and then the proximity distance is calculated, the amount of calculation will be extremely large. Therefore, in the work of spacecraft collision warning, in order to improve the calculation efficiency, it is necessary to quickly screen out the space targets that may have a rendezvous risk with the spacecraft from a large number of space targets, and then conduct subsequent proximity distance analysis and collision probability calculation. The commonly used screening methods include three-step screening such as perigee-apogee altitude screening, geocentric distance of the orbital plane intersection line screening, and time of passing through the intersection point screening. This method can effectively screen out a large number of targets that cannot intersect with the spacecraft. However, in order to ensure the reliability of the screening results, it is usually necessary to consider the compensation of orbital perturbation in the above screening methods, resulting in an increase in the amount of calculation and calculation time. Moreover, due to the influence of orbital perturbation factors, using the time of passing through the intersection point as a screening condition may cause missed warnings and reduce the reliability of collision warning. If only perigee-apogee altitude screening and geocentric distance of the orbital plane intersection line screening are used, and then based on the predicted ephemeris of the space target, the relative position and relative distance between the space target and the spacecraft are obtained. Although the risk of false alarms is small, the amount of calculation for orbital prediction and proximity distance is huge and the calculation time is long. That is, for the currently common methods for warning of spacecraft collisions, in order to ensure no missed warnings, most of them have a large amount of calculation, resulting in low efficiency of spacecraft collision warning. Therefore, it is necessary to find a more efficient and reliable method for warning of spacecraft collisions. Summary of the Invention

[0004] The embodiment of the present invention provides a method for warning of spacecraft collisions, which can reduce the amount of calculation for collision warning and improve the calculation efficiency of spacecraft collision warning while ensuring no missed warnings.

[0005] According to one aspect of an embodiment of the present invention, there is provided a method for collision warning of a spacecraft, including: obtaining first orbit data of the spacecraft and second orbit data of multiple space targets; performing epoch and perigee - apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft within a future time period; searching for a target time interval with potential rendezvous risk based on the first orbit data and the second orbit data of the candidate space targets; determining the minimum relative distance between the spacecraft and the candidate space targets within the target time interval, and determining a collision warning result of the spacecraft and the candidate space targets based on the minimum relative distance, where the collision warning result is used to represent whether there is a collision risk between the spacecraft and the candidate space targets within a future time period.

[0006] Optionally, performing epoch and perigee - apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets includes: screening the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, including: screening the multiple space targets based on the epoch moments of the multiple space targets in the second orbit data to obtain at least one initial space target, where the at least one initial space target is used to represent the space targets whose difference between the epoch moment in the TLE data and the current moment is less than a first preset threshold; screening the at least one initial space target based on the perigee and apogee altitude screening conditions of the candidate space targets to obtain candidate space targets, where the perigee altitude and apogee altitude of the candidate space targets satisfy the perigee and apogee altitude screening conditions of the candidate space targets, and the perigee and apogee altitude screening conditions of the candidate space targets are:

[0007] P0 < A s +D & A0 > P s -D;

[0008] where P0 is the perigee altitude of the initial space target, A s is the apogee altitude of the spacecraft, A0 is the apogee altitude of the initial space target, P s is the perigee altitude of the spacecraft, and D is the screening threshold for the perigee and apogee.

[0009] Optionally, based on the first orbit data and the second orbit data of the candidate space target, search for the target time interval with potential rendezvous risks, including: determining multiple warning time nodes based on the first orbit data and the second orbit data of the candidate space target; calculating the first position and the first velocity of the spacecraft corresponding to multiple warning time nodes, and the second position and the second velocity of the candidate space target corresponding to multiple warning time nodes based on the first orbit data and the second orbit data, and determining the relative distance change rate corresponding to multiple warning time nodes, where the relative distance change rate is used to characterize the change rate of the relative distance between the spacecraft and the candidate space target; determining the initial time interval where the relative distance minimum value between the spacecraft and the candidate space target is located based on the relative distance change rate corresponding to multiple warning time nodes; searching for the target time interval within the initial time interval, where the target time interval is used to characterize the time interval during which there may be a collision risk between the spacecraft and the candidate space target within the initial time interval.

[0010] Optionally, determining multiple warning time nodes based on the first orbit data and the second orbit data of the candidate space target includes: determining the minimum value between the first orbit operation period of the spacecraft and the second orbit operation period of the candidate space target based on the first orbit data and the second orbit data of the candidate space target to obtain the target orbit operation period; obtaining the ratio of the target orbit operation period to a preset value to obtain the prediction time interval; obtaining the sum value of the epoch moment of the spacecraft and a preset warning duration to obtain the warning end time; determining the warning time interval based on the epoch moment of the spacecraft and the warning end time; and sampling the warning time interval according to the prediction time interval to obtain multiple warning time nodes.

[0011] Optionally, calculating the first position and the first velocity of the spacecraft corresponding to multiple warning time nodes, and the second position and the second velocity of the candidate space target corresponding to multiple warning time nodes based on the first orbit data and the second orbit data, and determining the relative distance change rate corresponding to multiple warning time nodes includes:

[0012]

[0013] where is the first position corresponding to multiple warning time nodes, is the second position corresponding to multiple warning time nodes, is the relative position corresponding to multiple warning time nodes, is the first velocity corresponding to multiple warning time nodes, is the second velocity corresponding to multiple warning time nodes, is the relative velocity corresponding to multiple warning time nodes, and ρ is the relative distance corresponding to multiple warning time nodes. is the relative distance change rate corresponding to multiple warning time nodes.

[0014] Optionally, based on the relative distance change rate corresponding to multiple warning time nodes, determining the initial time interval where the minimum relative distance between the spacecraft and the candidate space target is located includes: obtaining the first relative distance change rate corresponding to the first time node among the multiple warning time nodes, and the second relative distance change rate corresponding to the second time node, where the first time node and the second time node are two adjacent time nodes among the multiple warning time nodes, and the first time node is earlier than the second time node; in response to the first relative distance change rate being less than the third preset threshold and the second relative distance change rate being greater than the third preset threshold, adding the time interval corresponding to the first time node and the second time node to the initial time interval.

[0015] Optionally, searching for the target time interval within the initial time interval includes: within the initial time interval, iteratively searching for the time interval where the minimum relative distance is located based on the target golden section method until the time range of the searched time interval is less than the preset duration; using the kinematic screening method to determine whether the searched time interval is the target time interval.

[0016] Optionally, iteratively searching for the time interval where the relative distance minimum value is located based on the target golden section method, including: based on the minimum time node, maximum time node, starting time node, golden section time node of the initial time interval, the first relative distance corresponding to the starting time node, and the second relative distance corresponding to the golden section time node, iteratively determining the search time interval within the initial time interval until the duration of the search time interval is less than the preset duration, where the starting time node is a node between the minimum time node and the maximum time node, selecting the starting time node as the midpoint of the initial time interval for the first iteration, and selecting the golden section time node as the golden section point of the initial time interval; in response to the starting time node being less than the golden section time node and the first relative distance being less than the second relative distance, determining the time interval formed by the minimum time node and the golden section time node as the search time interval, and determining the starting time node as the starting time node for the next time search; in response to the starting time node being less than the golden section time node and the first relative distance being greater than the second relative distance, determining the time interval formed by the starting time node and the maximum time node as the search time interval, and determining the golden section time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being less than the second relative distance, determining the time interval formed by the golden section time node and the maximum time node as the search time interval, and determining the starting time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being greater than the second relative distance, determining the time interval formed by the minimum time node and the starting time node as the search time interval, and determining the golden section time node as the starting time node for the next time search.

[0017] Optionally, using the kinematic screening method to determine whether the search time interval is the target time interval, including: based on the duration of the search time interval, using the kinematic screening method to determine the relative distance threshold; based on the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node in the search time interval, determining the smaller value between the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node, obtaining the relatively small distance value, comparing the relatively small distance value with the relative distance threshold, and in response to the relatively small distance value being greater than the relative distance threshold, no longer solving for the relative distance minimum value within the initial time interval, and repeating the steps of determining the target time interval in the next time interval of the initial time interval; in response to the relatively small distance value being less than or equal to the relative distance threshold, determining the search time interval as the target time interval.

[0018] Optionally, determine the minimum relative distance between the spacecraft and the candidate space target within the target time interval, and based on the minimum relative distance, determine the collision warning result between the spacecraft and the candidate space target, including: within the target time interval, use the target golden section method to continue iteratively searching for the time interval where the minimum relative distance is located until the time interval between the time nodes sampled by the golden section method twice in succession is less than the set threshold, and determine that the corresponding relative distance at this time is the minimum relative distance; compare the minimum relative distance with the collision warning threshold; in response to the minimum relative distance being greater than the collision warning threshold, determine that the collision warning result is that there is no collision risk between the spacecraft and the candidate space target in the future time period; in response to the minimum relative distance being less than the collision warning threshold, determine that the collision warning result is that there is a collision risk between the spacecraft and the candidate space target in the future time period, convert the minimum relative distance to the UNW coordinate system of the spacecraft to obtain multiple direction components; match the multiple direction components with the pre-determined warning level threshold to obtain the collision warning level; based on the collision warning level, determine whether to send a warning message.

[0019] According to another aspect of the embodiments of the present invention, there is also provided a collision warning device for a spacecraft, including: an acquisition module, configured to acquire first orbit data of the spacecraft and second orbit data of multiple space targets; a screening module, configured to perform epoch and perigee-apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft in the future time period; a search module, configured to search for a target time interval with a potential rendezvous risk based on the first orbit data and the second orbit data of the candidate space targets; a determination module, configured to determine the minimum relative distance between the spacecraft and the candidate space target within the target time interval, and based on the minimum relative distance, determine the collision warning result between the spacecraft and the candidate space target, where the collision warning result is used to represent whether there is a collision risk between the spacecraft and the candidate space target in the future time period.

[0020] According to another aspect of the embodiments of the present invention, there is also provided an electronic device, including: a memory, storing an executable program; a processor, configured to run the program, where when the program runs, it executes the methods in the various embodiments of the present invention.

[0021] According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium, where the computer-readable storage medium includes a stored executable program, and when the executable program runs, it controls the device where the computer-readable storage medium is located to execute the methods in the various embodiments of the present invention.

[0022] According to another aspect of the embodiments of the present invention, there is also provided a computer program product, including a computer program which, when executed by a processor, implements the methods in the various embodiments of the present invention.

[0023] According to another aspect of the embodiments of the present invention, there is also provided a computer program product, including a non-volatile computer-readable storage medium storing a computer program which, when executed by a processor, implements the methods in the various embodiments of the present invention.

[0024] According to another aspect of the embodiments of the present invention, there is also provided a computer program which, when executed by a processor, implements the methods in the various embodiments of the present invention.

[0025] In the embodiments of the present invention, first orbit data of a spacecraft and second orbit data of a plurality of space targets are acquired; epoch and perigee-apogee altitude screening are performed on the plurality of space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the plurality of space targets that may collide with the spacecraft within a future time period; a target time interval with potential rendezvous risks is searched based on the first orbit data and the second orbit data of the candidate space targets; a minimum relative distance between the spacecraft and the candidate space targets is determined within the target time interval, and a collision warning result between the spacecraft and the candidate space targets is determined based on the minimum relative distance. It is easy to notice that screening the space targets through the first orbit data and the second orbit data can reduce the calculation amount while accurately obtaining the candidate space targets. Secondly, large-step warning time nodes are set based on the first orbit data and the second orbit data to search for the target time intervals that may have collision risks, reducing the calculation amount of collision warning while ensuring no missed warnings, and further improving the calculation efficiency of collision warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0027] Figure 1 is a flowchart of a method for collision warning of a spacecraft according to an embodiment of the present invention;

[0028] Figure 2 is a flowchart of an optional method for quickly searching for the minimum relative distance according to an embodiment of the present invention;

[0029] Figure 3 is a flowchart of an optional method for screening candidate space targets and collision warning of a spacecraft according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the change in the relative distance between an optional candidate space target 43791 and a spacecraft 25544 according to an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of the change in the relative distance between an optional candidate space target 53708 and a spacecraft 25544 according to an embodiment of the present invention;

[0032] Figure 6 It is a schematic diagram of a collision warning device for a spacecraft according to an embodiment of the present invention. Detailed implementation manners

[0033] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] Embodiment 1

[0036] According to an embodiment of the present invention, an embodiment of a collision warning method for a spacecraft is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from that here.

[0037] Figure 1 It is a flowchart of a collision warning method for a spacecraft according to an embodiment of the present invention, as Figure 1 shown, the method includes the following steps:

[0038] Step S102: Obtain the first orbit data of the spacecraft and the second orbit data of multiple space targets.

[0039] The above-mentioned first orbit data may include but are not limited to: the number of the spacecraft, the epoch time, and the number of orbits around the Earth per day. The above-mentioned space targets may be other spacecrafts, satellites, space debris, etc. except the current spacecraft, but are not limited thereto. The above-mentioned second orbit data may include but are not limited to: the numbers of multiple space targets, the epoch time, and the number of orbits around the Earth per day.

[0040] It should be noted that the above-mentioned first orbit data and second orbit data are both Two-Line Element (TLE) data. TLE data is data released by the North American Aerospace Defense Command (NORAD) to describe the orbital information of artificial celestial bodies. When using TLE data for orbit prediction, it is necessary to combine with the SGP4 model. Among them, the SGP4 model is a space object orbit prediction model that takes into account the influence of disturbing forces such as the non-spherical gravity of the Earth, the gravitational forces of the sun and the moon, solar radiation pressure, and atmospheric drag, and has relatively high orbit prediction accuracy, and can solve the position and velocity of space objects at any time.

[0041] In an alternative embodiment, when it is necessary to determine the collision risk between the spacecraft and multiple space targets, first, the first orbit data of the spacecraft and the second orbit data of multiple space targets can be obtained.

[0042] Step S104: Perform epoch and perigee-apogee altitude screening on multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft in the future time period.

[0043] In an alternative embodiment, after obtaining the first orbit data and the second orbit data, in order to reduce the computational amount and accurately obtain the space targets that may collide with the spacecraft in the future time period, at this time, epoch and perigee-apogee altitude screening can be performed on multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets. For example, first, epoch screening can be performed on multiple space targets based on a first preset threshold to obtain at least one initial space target, and then perigee-apogee altitude screening can be performed on at least one initial space target based on the first orbit data and the second orbit data to obtain candidate space targets.

[0044] Step S106: Search for the target time interval with potential rendezvous risk based on the first orbit data and the second orbit data of the candidate space targets.

[0045] In an alternative embodiment, first, a plurality of early warning time nodes T can be determined based on the first orbit data and the second orbit data i , second, based on the first orbit data and the second orbit data, the SGP4 model can be used to calculate the first position and the first velocity of the spacecraft corresponding to the plurality of early warning time nodes, and the second position and the second velocity of the candidate space target corresponding to the plurality of early warning time nodes, and the relative distance change rate corresponding to the plurality of early warning time nodes can be determined Determine the initial time interval where the relative distance minimum value between the spacecraft and the candidate space target is located, then use the target golden section method to further search for the time interval where the relative distance minimum value is located, and finally use the kinematic screening method to determine the target time interval with potential collision risk

[0046] Step S108, determine the relative distance minimum value between the spacecraft and the candidate space target within the target time interval, and based on the relative distance minimum value, determine the collision early warning result between the spacecraft and the candidate space target, where the collision early warning result is used to characterize whether there is a collision risk between the spacecraft and the candidate space target in the future time period

[0047] The above-mentioned future time period can be a time period after the current time node, and the specific time duration is not limited in this embodiment and can be set according to actual early warning requirements. The above-mentioned relative distance minimum value can be the minimum value of the relative distance between the spacecraft and the candidate space target between adjacent early warning time nodes. It should be noted that the early warning time nodes can be calculated based on the number of orbits of the spacecraft around the earth per day in the first orbit data and the number of orbits of the space target around the earth per day in the second orbit data

[0048] In an alternative embodiment, first, the relative distance minimum value between the spacecraft and the candidate space target can be determined within the target time interval, and second, the relative distance minimum value ρ min and the collision early warning threshold D thBy making a comparison, a collision warning result is obtained. For example, the minimum relative distance can be compared with the collision warning threshold. When the minimum relative distance is greater than the collision warning threshold, it can be determined that the collision warning result is that there is no collision risk between the spacecraft and the candidate space target in the future time period, and at this time, no warning message needs to be sent; when the minimum relative distance is less than or equal to the collision warning threshold, it can be determined that the collision warning result is that there is a collision risk between the spacecraft and the candidate space target in the future time period. At this time, in order to more accurately determine the collision risk between the spacecraft and the candidate space target in the future time period, first, the minimum relative distance can be converted to the UNW coordinate system of the spacecraft to obtain three direction components, and based on the magnitudes of the three direction components, the collision warning level between the spacecraft and the candidate space target is determined, and whether to send a warning message is determined based on the collision warning level. For example, when it is determined that the collision warning level is a red warning, it can be determined that the collision risk between the spacecraft and the candidate space target in the future time period is extremely high, and at this time, it can be determined to send a warning message; when it is determined that the collision warning level is a yellow warning, it can be determined that the collision risk between the spacecraft and the candidate space target in the future time period is relatively high, and at this time, it can be determined to send a warning message; in the case where it is determined that the collision warning level is neither a red warning nor a yellow warning, it can be determined that the collision risk between the spacecraft and the candidate space target in the future time period is extremely low, and at this time, it can be determined not to send a warning message.

[0049] It should be noted that the warning message is used to alert the monitoring personnel that the collision risk between the spacecraft and the candidate space target in the future time period is relatively high or extremely high, so as to perform spacecraft collision avoidance in a timely manner. It should be noted that the above-mentioned collision warning level can indicate the magnitude of the collision risk between the spacecraft and the candidate space target in the future time period.

[0050] In an embodiment of the present invention, first orbit data of a spacecraft and second orbit data of multiple space targets are obtained; epoch and perigee - apogee altitude screening is performed on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft within a future time period; based on the first orbit data and the second orbit data of the candidate space targets, a target time interval with potential rendezvous risks is searched; the minimum relative distance between the spacecraft and the candidate space targets is determined within the target time interval, and based on the minimum relative distance, a collision warning result between the spacecraft and the candidate space targets is determined. It is easy to notice that screening the space targets through the first orbit data and the second orbit data can reduce the calculation amount while accurately obtaining the candidate space targets. Secondly, by setting large - step warning time nodes based on the first orbit data and the second orbit data, the target time interval with possible collision risks is searched. Without missing any warnings, the calculation amount of collision warning is reduced, and the calculation efficiency of collision warning is further improved.

[0051] Optionally, performing epoch and perigee - apogee altitude screening on multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets includes: screening the multiple space targets based on the epoch moments of the multiple space targets in the second orbit data to obtain at least one initial space target, where the at least one initial space target is used to represent the space targets whose difference between the epoch moment in the TLE data and the current moment is less than a first preset threshold; screening the at least one initial space target based on the perigee and apogee altitude screening conditions of the candidate space targets to obtain candidate space targets, where the perigee altitude and apogee altitude of the candidate space targets satisfy the perigee and apogee altitude screening conditions of the candidate space targets, and the perigee and apogee altitude screening conditions of the candidate space targets are:

[0052] P0 < A s +D & A0 > P s -D;

[0053] where P0 is the perigee altitude of the initial space target, A s is the apogee altitude of the spacecraft, A0 is the apogee altitude of the initial space target, P s is the perigee altitude of the spacecraft, D is the screening threshold for the perigee and apogee, and in this embodiment, D can be 50 km, but is not limited thereto.

[0054] The above - mentioned epoch moment refers to the epoch moment in the TLE data of the multiple space targets.

[0055] In an alternative embodiment, epoch screening can first be performed on multiple space objects. According to the epoch time in the TLE data of the space object, space objects with no updated TLE data within 7 days are screened out, and the screening condition is:

[0056] T b -T epoch >7 days;

[0057] where T b is the start time of the spacecraft collision warning time interval, T epoch is the epoch time of the TLE data of the space object, and 7 days is the first preset threshold. From the above formula, it can be seen that when the data update time of any one of the multiple space objects is greater than 7 days, that any one space object can be deleted, that is, at least one initial space object can be obtained. It should be noted that the specific value of the first preset threshold is not limited in this embodiment, and the user can set it according to actual needs. For example, it can also be 5 days, 2 weeks, etc.

[0058] In an alternative embodiment, candidate space objects can be determined by the following formula:

[0059] P0 < A s + D & A0 > P s - D;

[0060] where P0 is the perigee altitude of the initial space object, A s is the apogee altitude of the spacecraft, A0 is the apogee altitude of the initial space object, P s is the perigee altitude of the spacecraft, and D is the screening threshold for the perigee and apogee, which is set to 50 km in this embodiment.

[0061] Optionally, based on the first orbit data and the second orbit data of the candidate space object, search for the target time interval with potential rendezvous risks, including: based on the first orbit data and the second orbit data of the candidate space object, determine multiple warning time nodes; based on the first orbit data and the second orbit data, use the SGP4 model to calculate the first position and first velocity of the spacecraft corresponding to the multiple warning time nodes, and the second position and second velocity of the candidate space object corresponding to the multiple warning time nodes, and determine the relative distance change rate corresponding to the multiple warning time nodes, where the relative distance change rate is used to characterize the change rate of the relative distance between the spacecraft and the candidate space object; based on the relative distance change rate corresponding to the multiple warning time nodes, determine the initial time interval where the relative distance minimum value between the spacecraft and the candidate space object is located; search for the target time interval within the initial time interval, where the target time interval is used to characterize the time interval during which there may be a collision risk between the spacecraft and the candidate space object within the initial time interval.

[0062] In an alternative embodiment, the target orbit operation period can be obtained based on the first orbit data and the second orbit data. Secondly, the prediction time interval can be obtained based on the target orbit operation period. Then, the warning end time can be obtained based on the epoch time of the spacecraft, and the warning time interval can be obtained based on the warning end time and the epoch time of the spacecraft. Finally, the warning time interval can be sampled based on the prediction time interval to obtain a plurality of warning time nodes.

[0063] In another alternative embodiment, the relative distance change rate corresponding to a plurality of warning time nodes can be calculated based on the warning time nodes, the first position, the first velocity, the second position, and the second velocity.

[0064] In another alternative embodiment, the initial time interval can be calculated based on the relative distance change rate corresponding to a plurality of warning time nodes, and the target time interval between the spacecraft and the candidate space target can be determined within the initial time interval.

[0065] Optionally, determining a plurality of warning time nodes based on the first orbit data and the second orbit data of the candidate space target includes: determining the minimum value between the first orbit operation period of the spacecraft and the second orbit operation period of the candidate space target based on the first orbit data and the second orbit data of the candidate space target to obtain the target orbit operation period; obtaining the ratio of the target orbit operation period to a preset value to obtain the prediction time interval; obtaining the sum of the epoch time of the spacecraft and a preset warning duration to obtain the warning end time; determining the warning time interval based on the epoch time of the spacecraft and the warning end time; and sampling the warning time interval according to the prediction time interval to obtain a plurality of warning time nodes.

[0066] The above-mentioned first orbit operation period can be the period corresponding to the number of circles around the Earth per day in the TLE data of the spacecraft. The above-mentioned second orbit operation period can be the period corresponding to the number of circles around the Earth per day in the TLE data of the candidate space target. By obtaining the maximum value of the number of circles around the Earth per day in the TLE data of the spacecraft and the space target, the minimum value of the operation periods of the spacecraft and the candidate space target can be determined. The above-mentioned preset warning duration can be set in advance, and the specific value is not limited in this embodiment, and the user can set it according to actual needs.

[0067] In an alternative embodiment, first, the minimum value between the first orbit operation period and the second orbit operation period can be determined to obtain the target orbit operation period T min .

[0068] In another alternative embodiment, the prediction time interval ΔT can be obtained through the following formula:

[0069]

[0070] Among them, 5 is a preset value.

[0071] In another alternative embodiment, the early warning end time T can be obtained through the following formula e :

[0072] T e = T b + T;

[0073] Among them, T b is the epoch time of the spacecraft, and T is the preset early warning duration.

[0074] In another alternative embodiment, the epoch time of the spacecraft and the early warning end time can be used as the two endpoints of the early warning time interval respectively, that is, the early warning time interval can be obtained as T e = T b + T.

[0075] In another alternative embodiment, multiple early warning time nodes T can be obtained through the following formula i :

[0076] T i = T b + ΔT * (i - 1), i ≥ 1;

[0077] Among them, it can be seen from the above formula that by sampling the early warning time interval at a preset time interval, multiple early warning time nodes T can be obtained i .

[0078] Optionally, based on the first orbit data and the second orbit data, the SGP4 model is used to calculate the first position and the first velocity of the spacecraft corresponding to multiple early warning time nodes, as well as the second position and the second velocity of the candidate space target corresponding to multiple early warning time nodes, and determine the relative distance change rate corresponding to multiple early warning time nodes, including:

[0079]

[0080] Among them, is the first position corresponding to multiple early warning time nodes, is the second position corresponding to multiple early warning time nodes, is the relative position corresponding to multiple early warning time nodes, is the first velocity corresponding to multiple early warning time nodes, is the second velocity corresponding to multiple early warning time nodes, is the relative velocity corresponding to multiple early warning time nodes, ρ is the relative distance corresponding to multiple early warning time nodes, is the relative distance change rate corresponding to multiple early warning time nodes.

[0081] In an alternative embodiment, the relative positions of multiple warning time nodes can be obtained through the following formula first

[0082]

[0083] where is the first position corresponding to multiple warning time nodes is the second position corresponding to multiple warning time nodes

[0084] In another alternative embodiment, the relative speed corresponding to multiple warning time nodes can be obtained through the following formula

[0085]

[0086] where is the first speed corresponding to multiple warning time nodes is the second speed corresponding to multiple warning time nodes

[0087] In another alternative embodiment, the relative distance ρ corresponding to multiple warning time nodes can be obtained through the following formula

[0088]

[0089] where, as can be seen from the above formula, taking the absolute value of can obtain the relative distance

[0090] In another alternative embodiment, the relative distance change rate corresponding to multiple warning time nodes can be obtained through the following formula

[0091]

[0092] Optionally, based on the relative distance change rate corresponding to multiple warning time nodes, determining the initial time interval where the minimum relative distance between the spacecraft and the candidate space target is located includes: obtaining the first relative distance change rate corresponding to the first time node among multiple warning time nodes, and the second relative distance change rate corresponding to the second time node, where the first time node and the second time node are two adjacent time nodes among multiple warning time nodes, and the first time node is earlier than the second time node; when the first relative distance change rate is less than the third preset threshold and the second relative distance change rate is greater than the third preset threshold, adding the time interval corresponding to the first time node and the second time node to the initial time interval

[0093] The above-mentioned third preset threshold is 0

[0094] In an alternative embodiment, first, according to the rate of change of the relative distance between the spacecraft and the candidate space target at time T i (i.e., the first time node) and time T i+1 (i.e., the second time node), (i.e., the first rate of change of relative distance) and (i.e., the second rate of change of relative distance), judge the time interval where the relative distance minimum value is located. If and then it can be determined that the time interval with the first time node and the second time node as endpoints is the initial time interval [T i , T i+1 , that is, there is a relative distance minimum value within [T i , T i+1 ; otherwise, there is no relative distance minimum value within the time interval [T i , T i+1 , and continue to judge whether there is a relative distance minimum value within the next time interval [T i+1 , T i+2 .

[0095] Optionally, searching for the target time interval within the initial time interval includes: within the initial time interval, iteratively searching for the time interval where the relative distance minimum value is located based on the target golden section method until the time range of the searched time interval is less than the preset duration; using the kinematic screening method to judge whether the searched time interval is the target time interval.

[0096] The above-mentioned target golden section method is: first compare the time magnitudes and relative distance magnitudes of the 2 time nodes in the initial time interval [T i , T i+1 , and then delete the left-end time node T i (i.e., the minimum time node) or the right-end time node T i+1 (i.e., the maximum time node) according to the comparison result to narrow the search time interval of the relative distance minimum value, and then solve the time interval where the relative distance minimum value is located through iteration. The above-mentioned preset duration can be set according to actual needs and is not limited in this embodiment.

[0097] It should be noted that the improved golden section method requires 3 time nodes as the starting point. In the first iteration process, in addition to the time nodes T i and T i+1 , determine the middle time T i of the initial time interval [T i+1 , T c = (T i + T i+1) / 2 is the 3rd starting point (i.e., the starting time node), and the positions of the space target and the spacecraft at time T are obtained respectively using the SGP4 model, and then the relative position and relative distance between the two (i.e., the first relative distance) are calculated. c It should be noted that within the target time interval screened by kinematics, the minimum relative distance between the spacecraft and the candidate space target is determined. Within the target time interval, the golden section method of the target is used to continue searching for the time interval where the minimum relative distance is located until the interval between the starting time node and the golden section time node is less than the set threshold, and the corresponding relative distance at this time is the minimum relative distance.

[0098] In an alternative embodiment, first, within the initial time interval, the time interval where the minimum relative distance is located can be iteratively searched based on the golden section method of the target until the time range of the search time interval is less than the preset duration. Second, the kinematic screening method can be used to determine whether the search time interval is the target time interval. In the case where it is determined that the search time interval is the target time interval, the minimum relative distance between the spacecraft and the candidate space target can be determined within the target time interval.

[0099]

[0100] ​Optionally, iteratively search for the time interval where the relative distance minimum value is located based on the golden section method, including: based on the minimum time node, maximum time node, starting time node, golden section time node, the first relative distance corresponding to the starting time node, and the second relative distance corresponding to the golden section time node of the initial time interval, iteratively determine the search time interval within the initial time interval until the duration of the search time interval is less than the preset duration, where the starting time node is a node between the minimum time node and the maximum time node, when performing the first iteration, select the starting time node as the midpoint of the initial time interval, and select the golden section time node as the golden section point of the initial time interval; in response to the starting time node being less than the golden section time node and the first relative distance being less than the second relative distance, determine the time interval formed by the minimum time node and the golden section time node as the search time interval, and determine the starting time node as the starting time node for the next time search; in response to the starting time node being less than the golden section time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the starting time node and the maximum time node as the search time interval, and determine the golden section time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being less than the second relative distance, determine the time interval formed by the golden section time node and the maximum time node as the search time interval, and determine the starting time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the minimum time node and the starting time node as the search time interval, and determine the golden section time node as the starting time node for the next time search.

[0101] The above-mentioned first relative distance is ρ c , and the second relative distance is ρ g .

[0102] In an alternative embodiment, first, the minimum time node, maximum time node, starting time node, and golden section time node of the initial time interval can be determined. Secondly, the first relative distance corresponding to the starting time node and the second relative distance corresponding to the golden section time node can be determined. Then, the search time interval within the initial time interval can be iteratively determined until the duration of the search time interval is less than the preset duration. It should be noted that when performing the first iteration, the starting time node can be selected as the midpoint of the initial time interval, and the golden section time node can be selected as the golden section point of the initial time interval.

[0103] In another alternative embodiment, the golden section method can be used to obtain the 4th time node T g = T i + 0.618×(Ti+1 -T i )(i.e., the golden section time node), and use the SGP4 model to obtain the positions of the space target and the spacecraft at time T g respectively, and then calculate the relative position and relative distance between the two (i.e., the second relative distance);

[0104] In another alternative embodiment, the relative distance values of the space target and the spacecraft at time T c (i.e., the starting time node) and time T g (i.e., the golden section time node) can be compared. If T c <T g , and ρ c <ρ g , then delete the time node T i+1 . It is possible to determine that the search time interval is [T i , T g . Continue to find the minimum value of the relative distance within the search time interval [T i , T g ; and the starting time node is the starting time node for the next time search.

[0105] In another alternative embodiment, if T c <T g , and ρ c >ρ g , then delete the time node T i . It is possible to determine that the search time interval is [T c , T i+1 . Continue to find the minimum value of the relative distance within the search time interval [T c , T i+1 , and determine the golden section time node as the starting time node for the next time search.

[0106] In another alternative embodiment, if T c >T g , and ρ c <ρ g , it is possible to determine that the search time interval is [T g , T i+1 , and determine the starting time node as the starting time node for the next time search.

[0107] In yet another alternative embodiment, T c >T g , and ρ c >ρ g , it is possible to determine that the search time interval is [T i , T c , and determine the golden section time node as the starting time node for the next time search.

[0108] Optionally, a kinematic screening method is used to determine whether the search time interval is the target time interval, including: based on the duration of the search time interval, determining the relative distance threshold by using the kinematic screening method; based on the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node in the search time interval, determining the smaller value between the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node, obtaining the smaller relative distance value, comparing the smaller relative distance value with the relative distance threshold, and in response to the smaller relative distance value being greater than the relative distance threshold, no longer solving for the minimum relative distance value in the subsequent initial time interval, and in the next time interval of the initial time interval, repeating the steps of determining the target time interval; in response to the smaller relative distance value being less than or equal to the relative distance threshold, determining that the search time interval is the target time interval.

[0109] In an alternative embodiment, based on the duration of the search time interval, a kinematic screening method is used to determine the relative distance threshold. Since the relative distance between the candidate space target and the spacecraft first decreases monotonically and then increases monotonically within the search time interval [T m ,T n , the candidate space target first enters the space range with a radius of ρ min around the spacecraft within Δt time and then leaves this space range. Therefore, if the difference between the relative distance ρ min between the candidate space target and the spacecraft at time T min and the collision warning threshold is greater than V esc ·Δt, the space target cannot enter the collision warning threshold of the spacecraft within Δt time. Given that the known collision warning threshold between the space target and the spacecraft is D th , the relative distance threshold R th can be obtained through the following formula:

[0110]

[0111] where is a constant, d esc is the maximum relative distance change, V esc is the escape velocity, and D th is the collision warning threshold.

[0112] In another alternative embodiment, the maximum relative distance change d esc can be obtained through the following formula:

[0113] d esc = 2·V esc ·Δt;

[0114] where 2 is a constant value.

[0115] It should be noted that the relative velocity between the candidate space target and the spacecraft will not exceed 2 times the escape velocity V esc , and the magnitude of the escape velocity is 7.9 km / s. The change in the relative distance between the two within Δt will not exceed d esc .

[0116] In another alternative embodiment, the relatively small value ρ of the relative distance can be obtained through the following formula min :

[0117] ρ min = min(ρ m , ρ n );

[0118] Among them, ρ m is the relative distance corresponding to the minimum time node in the search time interval, and ρ n is the relative distance corresponding to the maximum time node in the search time interval. The time endpoint corresponding to the relatively small value of the relative distance is denoted as T min , T min = T m , or T min = T n .

[0119] In another alternative embodiment, after obtaining the relatively small value of the relative distance, the relatively small value of the relative distance can be compared with the relative distance threshold R th . In the case where the relatively small value of the relative distance is greater than the relative distance threshold, it is not necessary to solve the minimum value of the relative distance in the subsequent initial time interval, and in the next time interval of the initial time interval, the steps of determining the target time interval are repeated; when the relatively small value of the relative distance is less than or equal to the relative distance threshold, the search time interval is determined as the target time interval.

[0120] In another alternative embodiment, if the relative distance ρ between the space target and the spacecraft at time T min is greater than the relative distance threshold R min , then the minimum value of the relative distance between the space target and the spacecraft within the search time interval [T th , T m must be greater than the spacecraft collision warning threshold D n , it is considered that there is no collision risk between the space target and the spacecraft, so the solution of the minimum value of the relative distance is no longer carried out in the subsequent search time interval [T th , T m , and continue to judge whether there is a minimum value of the relative distance in the next time interval [T n ; if the relative distance ρ between the space target and the spacecraft at time T i+1 is greater than the relative distance threshold R i+2 , then the minimum value of the relative distance between the space target and the spacecraft within the search time interval [T min must be greater than the spacecraft collision warning threshold Dmin less than the relative distance threshold R th , then the minimum relative distance between the space target and the spacecraft within the search time interval [T m , T n may be less than the spacecraft collision warning threshold D th , and it is considered that there may be a collision risk between the space target and the spacecraft. Define the search time interval [T m , T n with possible rendezvous risk as the potential rendezvous risk interval. At this time, the search time interval [T m , T n can be determined as the target time interval, and the minimum relative distance is solved within the target time interval.

[0121] It should be noted that in this application, Δt th is selected to be 120 s. If the iteration process stops and the search time interval where the minimum relative distance is located is [T m , T n , then there is:

[0122] Δt = |T m - T n | < Δt th .

[0123] where Δt th is the preset duration.

[0124] At this time, the search time interval can be determined as the target time interval.

[0125] Optionally, within the target time interval, determine the minimum relative distance between the spacecraft and the candidate space target, and based on the minimum relative distance, determine the collision warning result between the spacecraft and the candidate space target, including: within the target time interval, use the target golden section method to continue iterative search for the time interval where the minimum relative distance is located until the time interval between the time nodes of two adjacent golden section method samplings is less than the set threshold, and determine the corresponding relative distance at this time as the minimum relative distance; compare the minimum relative distance with the collision warning threshold; in response to the minimum relative distance being greater than the collision warning threshold, determine that the collision warning result is that there is no collision risk between the spacecraft and the candidate space target in the future time period; in response to the minimum relative distance being less than the collision warning threshold, determine that the collision warning result is that there is a collision risk between the spacecraft and the candidate space target in the future time period, convert the minimum relative distance to the UNW coordinate system of the spacecraft to obtain multiple direction components; match the multiple direction components with the pre-determined warning level threshold to obtain the collision warning level; based on the collision warning level, determine whether to issue a warning message.

[0126] The above-mentioned pre-determined warning level thresholds have a corresponding relationship with the collision warning levels, including multiple warning level thresholds. Based on specific warning level thresholds, specific collision warning levels can be determined. The origin of the above-mentioned UNW coordinate system is at the center of mass of the spacecraft. The U direction is the direction of the spacecraft's velocity vector. The N direction is perpendicular to the U direction within the orbital plane and points to the orbital normal direction. The W direction forms a right-handed system with the U and N directions and can be used to describe the relative position between the space target and the spacecraft.

[0127] Among them, the number and specific values of the specific warning level thresholds can be set according to actual warning requirements and are not limited in this embodiment. In this embodiment, the number of warning level thresholds is taken as an example of 2 for illustration, but it is not limited thereto. It can also be 1, 3, etc. Among them, when the number of warning level thresholds is 2, the values of the first warning level threshold in the three directions of U, N, and W can be 4 km × 0.5 km × 4 km, and the corresponding collision warning level of this first warning level threshold is a red warning. The values of the second warning level threshold in the three directions of U, N, and W can be 25 km × 2 km × 25 km, and the corresponding collision warning level of this second warning level threshold is a yellow warning.

[0128] Among them, the warning threshold values in the three directions of U, N, and W are respectively the trace direction (U), radial direction (N), and transverse direction (W) distance criteria of the candidate space target and the spacecraft in the spacecraft's UNW coordinate system.

[0129] The above specific values are only examples in this embodiment and can also be other values not shown.

[0130] In an alternative embodiment, within the target time interval [T m , T n , the minimum value of the relative distance between the space target and the spacecraft is accurately solved. Within the target time interval [T m , T n , the golden section method of the target is used to continue iteratively searching for the time interval where the minimum value of the relative distance is located until the time interval between the time nodes sampled by the golden section method twice in succession is less than 1 ms, then the iteration stops, and the approaching time T a and the corresponding distance ρ a can be determined. That is, the minimum value of the relative distance can be determined as ρ a .

[0131] In another alternative embodiment, if the minimum value ρ a of the relative distance between the candidate space target and the spacecraft is greater than the spacecraft collision warning threshold D th , it is considered that there is no collision risk between the spacecraft and the candidate space target in the future time period; if the minimum value ρa Less than the spacecraft collision warning threshold D th , it is considered that there is a collision risk between the spacecraft and the candidate space target in the future time period. At this time, the relative distance minimum value can be converted to the spacecraft UNW coordinate system, and the components in the three directions of the trace direction (U), radial direction (N), and transverse direction (W) in the spacecraft UNW coordinate system can be calculated, and the components in the three directions are compared with the three components of the pre-determined warning level threshold to obtain the collision warning level of the candidate space target and the spacecraft, and based on the collision warning level, it is determined whether to send a warning message.

[0132] For example, after obtaining the components in the three directions of U, N, and W of the relative distance minimum value, the three components can be respectively compared with the corresponding 4 (U-direction distance threshold), 0.5 (N-direction distance threshold), and 4 (W-direction distance threshold) in the first warning level threshold of 4 km × 0.5 km × 4 km. When all three components are less than or equal to the first warning level threshold, it can be determined that the collision warning level between the spacecraft and the candidate space target is a red warning, that is, the collision risk between the spacecraft and the candidate space target in the future time period is extremely high. At this time, it can be determined to send a warning message.

[0133] And when it is determined that any one of the three components is greater than the first warning level threshold, at this time, the three components can be respectively compared with 25, 2, and 25 in the second warning level threshold of 25 km × 2 km × 25 km. When all three components are less than or equal to the second warning level threshold, it can be determined that the collision warning level between the spacecraft and the candidate space target is a yellow warning, that is, the collision risk between the spacecraft and the candidate space target in the future time period is relatively high. At this time, it can be determined to send a warning message.

[0134] And when it is determined that any one of the three components is greater than the second warning level threshold, it indicates that the collision risk between the spacecraft and the candidate space target in the future time period is extremely low. At this time, it can be determined not to send a warning message.

[0135] Figure 2 is a flowchart of an optional method for quickly searching for the relative distance minimum value according to an embodiment of the present invention. As Figure 2 shown, the method includes:

[0136] Step S21, set the spacecraft collision warning threshold and warning duration;

[0137] Step S22, obtain the orbital data of the spacecraft and the space target;

[0138] Step S23, candidate space target screening, screen the space target according to the epoch time and the perigee-apogee altitude, and select the candidate space target that may have a collision risk with the spacecraft;

[0139] Step S24: Traverse the candidate space targets that pass the screening, calculate the relative distance change rate between the spacecraft and the candidate space targets at each moment (i.e., the above warning time nodes), and preliminarily determine the time interval where the relative distance minimum value is located.

[0140] Step S25: Within the time interval where the relative distance minimum value is located, preliminarily judge the rendezvous risk between the candidate space target and the spacecraft based on the kinematic screening method, and find the time interval where the rendezvous risk may exist.

[0141] Step S26: Judge whether the kinematic screening conditions are met. If so, enter Step S27; if not, enter Step S24.

[0142] Step S27: In the potential rendezvous risk interval that passes the kinematic screening, accurately solve the relative distance minimum value between the candidate space target and the spacecraft, and conduct a collision risk analysis according to the collision warning threshold.

[0143] The method of the present invention can reduce the computational amount of spacecraft collision warning and improve the collision warning efficiency.

[0144] Figure 3 It is a flowchart of an optional method for screening candidate space targets and warning of spacecraft collision according to an embodiment of the present invention. As Figure 3 shown, the method includes the following steps:

[0145] Step S31: Set the collision warning threshold D th and the warning duration T of the spacecraft.

[0146] Step S32: Obtain the NORAD number of the spacecraft and the orbital data of the spacecraft and all space targets. The orbital data of the spacecraft and the space targets are TLE data.

[0147] Step S33: Epoch time screening.

[0148] Step S34: Perigee - apogee altitude screening.

[0149] Step S35: Set the orbital prediction time interval between the spacecraft and the candidate space target.

[0150] Step S36: Traverse the candidate space targets and enter Step S37.

[0151] Step S37: Within the warning period, traverse each warning time node, and calculate the relative distance change rate between the spacecraft and the candidate space target at adjacent nodes in turn.

[0152] Step S38: Judge whether there is a relative distance minimum value. If so, enter Step S39; if not, return to Step S37.

[0153] Step S39, kinematic screening to preliminarily judge the rendezvous risk;

[0154] Step S310, judge whether the kinematic screening conditions are met. If so, enter Step S311; if not, return to Step S37.

[0155] Step S311, accurately solve the minimum relative distance.

[0156] Step S312, judge whether all candidate space targets have been analyzed. If so, enter Step S313; if not, return to Step S36.

[0157] Step S313, output the collision warning result.

[0158] The technology implemented by the design of the present invention has the following advantages:

[0159] (1) The orbit prediction and proximity analysis of the spacecraft and candidate space targets are both carried out in the TEME coordinate system. Compared with the prior art which usually calculates in the J2000 coordinate system, the conversion process from the TEME coordinate system to the J2000 coordinate system is omitted, resulting in less calculation amount and higher efficiency.

[0160] (2) The present method proposes to perform orbit prediction and collision risk analysis at intervals of 1 / 5 of the shortest orbit operation period of the spacecraft and candidate space targets, ensuring that there is at most one minimum relative distance value between adjacent time nodes. It can improve the collision warning efficiency while avoiding missed warnings and is applicable to all spacecraft.

[0161] (3) In the process of solving the minimum relative distance value, the present method adopts an improved minimum value search method. The prior art usually uses the bisection method to perform iterative search for the minimum value by judging the sign of the relative distance change rate of an intermediate node. The present method uses the improved golden section method to search for the minimum value by comparing the numerical sizes of the relative distances of two intermediate nodes, without the need to solve the relative distance change rate, simplifying the solution steps and further reducing the calculation amount.

[0162] (4) The present method uses a kinematic screening method to find the time interval where a rendezvous risk may exist, excluding the time intervals where collision events are impossible to occur, thereby reducing the calculation amount of solving the minimum relative distance value.

[0163] Figure 4 It is a schematic diagram of the relative distance change between an optional candidate space target 43791 and a spacecraft 25544 according to an embodiment of the present invention. Figure 5It is a schematic diagram of the relative distance change between an optional candidate space target 53708 and a spacecraft 25544 according to an embodiment of the present invention. Taking the collision warning analysis of the spacecraft with NORAD number 25544 as an example to introduce the advantages of the present invention. Using the TLE data of the spacecraft and the candidate space target on December 17, 2022, a collision warning analysis with a warning duration of 3 days is carried out on the spacecraft. The collision warning threshold of the spacecraft is set to 50 km, and the warning time period is from 0:00 on December 17, 2022 to 0:00 on December 20, 2022. Two candidate space targets selected through epoch screening and perigee-apogee altitude screening, with NORAD numbers 43791 and 53708 respectively. The relative distances between the two candidate space targets and the spacecraft during the warning period are plotted, as shown respectively in Figure 4 , Figure 5 . Among them, the horizontal line in the figure is the maximum relative distance threshold R max_th :

[0164] R max_th =V esc ·Δt th +D th =7.9×120 + 50≈1000.

[0165] After the conventional collision warning method initially determines the time interval range of the relative distance minimum through the sign of the relative distance change rate, it is necessary to search all time intervals with relative distance minima. However, this method sets the relative distance threshold through the kinematic screening method, which can quickly exclude time intervals without rendezvous risks and narrow the time search range of the relative distance minimum. In this case, from Figure 4 and Figure 5 , it can be seen that there are 93 relative distance minima between the candidate space target 43791 and the spacecraft 25544 during the 3-day warning period. This method initially judges the collision risk through the kinematic screening method, and at most only needs to solve the 16 relative distance minima located below the horizontal line in Figure 4 ; for the candidate space target 53708, only the kinematic screening method is needed to initially judge its collision risk with the spacecraft, and there is no need to accurately solve the relative distance minimum, which greatly reduces the computational amount of iterative solution of the minimum value.

[0166] Embodiment 2

[0167] According to another aspect of the embodiments of the present invention, a collision warning device for a spacecraft is further provided. This device can execute the collision warning method for a spacecraft provided in the above Embodiment 1. The specific implementation manner and preferred application scenario are the same as those in the above Embodiment 1, and will not be elaborated here.

[0168] Figure 6 It is a schematic diagram of a collision warning device for a spacecraft according to an embodiment of the present invention, asFigure 6 As shown in the figure, the device includes: an acquisition module 62 for acquiring the first orbital data of the spacecraft and the second orbital data of multiple space targets; a screening module 64 for screening the multiple space targets based on the first orbital data and the second orbital data in terms of epoch and perigee-apogee altitude to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft within a future time period; a search module 66 for searching for a target time interval with potential rendezvous risks based on the first orbital data and the second orbital data of the candidate space targets; and a determination module 68 for determining the minimum relative distance between the spacecraft and the candidate space targets within the target time interval and, based on the minimum relative distance, determining a collision warning result between the spacecraft and the candidate space targets, where the collision warning result is used to represent whether there is a collision risk between the spacecraft and the candidate space targets within a future time period.

[0169] Optionally, the screening module includes: a first screening unit for screening the multiple space targets based on the epoch moments of the multiple space targets in the second orbital data to obtain at least one initial space target, where the at least one initial space target is used to represent the space targets whose difference between the epoch moment in the TLE data and the current moment is less than a first preset threshold; and a second screening unit for screening the at least one initial space target based on the perigee and apogee altitude screening conditions of the candidate space targets to obtain candidate space targets, where the perigee altitude and apogee altitude of the candidate space targets satisfy the perigee and apogee altitude screening conditions of the candidate space targets, and the perigee and apogee altitude screening conditions of the candidate space targets are:

[0170] P0 < A s + D & A0 > P s - D;

[0171] where P0 is the perigee altitude of the initial space target, A s is the apogee altitude of the spacecraft, A0 is the apogee altitude of the initial space target, P s is the perigee altitude of the spacecraft, and D is the screening threshold for the perigee and apogee.

[0172] Optionally, the search module includes: a first determination unit configured to determine multiple warning time nodes based on the first orbit data and the second orbit data of the candidate space target; a second determination unit configured to calculate, based on the first orbit data and the second orbit data, the first position and the first velocity of the spacecraft corresponding to the multiple warning time nodes, and the second position and the second velocity of the candidate space target corresponding to the multiple warning time nodes by using the SGP4 model, and determine the relative distance change rate corresponding to the multiple warning time nodes, where the relative distance change rate is used to characterize the change rate of the relative distance between the spacecraft and the candidate space target; a third determination unit configured to determine the initial time interval where the relative distance minimum value between the spacecraft and the candidate space target is located based on the relative distance change rate corresponding to the multiple warning time nodes; a first search unit configured to search for the target time interval within the initial time interval, where the target time interval is used to characterize the time interval during which there may be a collision risk between the spacecraft and the candidate space target within the initial time interval.

[0173] Optionally, the first determination unit includes: a first acquisition subunit configured to determine the minimum value between the first orbit operation period of the spacecraft and the second orbit operation period of the candidate space target based on the first orbit data and the second orbit data of the candidate space target, and obtain the target orbit operation period; a second acquisition subunit configured to obtain the ratio of the target orbit operation period to a preset value to obtain the prediction time interval; a third acquisition subunit configured to obtain the sum value of the epoch moment of the spacecraft and the preset warning duration to obtain the warning end time; a first determination subunit configured to determine the warning time interval based on the epoch moment of the spacecraft and the warning end time; a sampling subunit configured to sample the warning time interval according to the prediction time interval to obtain multiple warning time nodes.

[0174] Optionally, the second determination unit is configured to:

[0175]

[0176] Where is the first position corresponding to the multiple warning time nodes, is the second position corresponding to the multiple warning time nodes, is the relative position corresponding to the multiple warning time nodes, is the first velocity corresponding to the multiple warning time nodes, is the second velocity corresponding to the multiple warning time nodes, is the relative velocity corresponding to the multiple warning time nodes, ρ is the relative distance corresponding to the multiple warning time nodes, is the relative distance change rate corresponding to the multiple warning time nodes.

[0177] Optionally, the third determination unit includes: a fourth acquisition subunit, configured to acquire a first relative distance change rate corresponding to a first time node and a second relative distance change rate corresponding to a second time node among a plurality of warning time nodes, where the first time node and the second time node are two adjacent time nodes among the plurality of warning time nodes, and the first time node is earlier than the second time node; an addition subunit, configured to, in response to the first relative distance change rate being less than a third preset threshold and the second relative distance change rate being greater than the third preset threshold, add the time interval corresponding to the first time node and the second time node to the initial time interval.

[0178] Optionally, the first search unit includes: a search subunit, configured to iteratively search for the time interval where the relative distance minimum value is located within the initial time interval based on the target golden section method until the time range of the search time interval is less than a preset duration; a judgment subunit, configured to use a kinematic screening method to judge whether the search time interval is the target time interval.

[0179] Optionally, the search subunit is further configured to: iteratively determine the search time interval within the initial time interval based on the minimum time node, the maximum time node, the starting time node, the golden section time node, the first relative distance corresponding to the starting time node, and the second relative distance corresponding to the golden section time node of the initial time interval until the duration of the search time interval is less than a preset duration, where the starting time node is a node between the minimum time node and the maximum time node, the starting time node is selected as the midpoint of the initial time interval for the first iteration, and the golden section time node is selected as the golden section point of the initial time interval; in response to the starting time node being less than the golden section time node and the first relative distance being less than the second relative distance, determine the time interval formed by the minimum time node and the golden section time node as the search time interval, and determine the starting time node as the starting time node for the next time search; in response to the starting time node being less than the golden section time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the starting time node and the maximum time node as the search time interval, and determine the golden section time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being less than the second relative distance, determine the time interval formed by the golden section time node and the maximum time node as the search time interval, and determine the starting time node as the starting time node for the next time search; in response to the starting time node being greater than the golden section time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the minimum time node and the starting time node as the search time interval, and determine the golden section time node as the starting time node for the next time search.

[0180] Optionally, the determination subunit is further configured to: determine a relative distance threshold using a kinematic screening method based on the duration of the search time interval; determine the smaller value between the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node in the search time interval, to obtain a smaller relative distance value, compare the smaller relative distance value with the relative distance threshold, and in response to the smaller relative distance value being greater than the relative distance threshold, it is not necessary to solve for the minimum relative distance in the subsequent initial time interval, and in the next time interval of the initial time interval, repeat the step of determining the target time interval; in response to the smaller relative distance value being less than or equal to the relative distance threshold, determine the search time interval as the target time interval.

[0181] Optionally, the determination module includes: a second search unit, configured to continue iteratively searching for the time interval where the minimum relative distance is located within the target time interval using the target golden section method until the time interval between the time nodes sampled by the golden section method twice in succession is less than a set threshold, and determine the corresponding relative distance at this time as the minimum relative distance; a comparison unit, configured to compare the minimum relative distance with the collision warning threshold; a fourth determination unit, configured to, in response to the minimum relative distance being greater than the collision warning threshold, determine that the collision warning result is whether there is a collision risk between the spacecraft and the candidate space target in the future time period; a fifth determination unit, configured to, in response to the minimum relative distance being less than the collision warning threshold, determine that the collision warning result is that there is a collision risk between the spacecraft and the candidate space target in the future time period, convert the minimum relative distance to the UNW coordinate system of the spacecraft to obtain multiple direction components; a matching unit, configured to match the multiple direction components with the pre-determined warning level threshold to obtain the collision warning level; a sixth determination unit, configured to determine whether to send a warning message based on the collision warning level.

[0182] Embodiment 3

[0183] An embodiment of the present application further provides an electronic device, including: a memory storing an executable program; a processor configured to run the program, where when the program runs, it executes the methods in the various embodiments of the present invention.

[0184] Embodiment 4

[0185] An embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium includes a stored executable program, and when the executable program runs, it controls the device where the computer-readable storage medium is located to execute the methods in the various embodiments of the present invention.

[0186] Embodiment 5

[0187] An embodiment of the present application also provides a computer program product, including a computer program which, when executed by a processor, implements the methods in various embodiments of the present invention.

[0188] Embodiment 6

[0189] An embodiment of the present application also provides a computer program product, including a non-volatile computer-readable storage medium for storing a computer program which, when executed by a processor, implements the methods in various embodiments of the present invention.

[0190] Embodiment 7

[0191] An embodiment of the present application also provides a computer program which, when executed by a processor, implements the methods in various embodiments of the above-mentioned present invention.

[0192] The serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.

[0193] In the above-mentioned embodiments of the present invention, the descriptions of the various embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0194] In the several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the units or modules can be in electrical or other forms.

[0195] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0196] In addition, the functional units in various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0197] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), mobile hard disks, magnetic disks, or optical discs.

[0198] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A collision warning method for a spacecraft, characterized in that, Including: Obtaining first orbit data of a spacecraft and second orbit data of multiple space targets; Performing epoch and perigee - apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, where the candidate space targets are used to represent the space targets among the multiple space targets that may collide with the spacecraft within a future time period; Searching for a target time interval with potential rendezvous risks based on the first orbit data and the second orbit data of the candidate space targets; Determining a minimum relative distance between the spacecraft and the candidate space targets within the target time interval, and determining a collision warning result between the spacecraft and the candidate space targets based on the minimum relative distance, where the collision warning result is used to represent whether there is a collision risk between the spacecraft and the candidate space targets within the future time period; Searching for a target time interval with potential rendezvous risks based on the first orbit data and the second orbit data of the candidate space targets, including: Determining a minimum value between the first orbit operation period of the spacecraft and the second orbit operation period of the candidate space targets based on the first orbit data and the second orbit data of the candidate space targets to obtain a target orbit operation period; Obtaining a ratio of the target orbit operation period to a preset value to obtain a prediction time interval; Obtaining a sum value of the epoch moment of the spacecraft and a preset warning duration to obtain a warning end time; Determining a warning time interval based on the epoch moment of the spacecraft and the warning end time; Sampling the warning time interval according to the prediction time interval to obtain a plurality of warning time nodes; Determining relative distance change rates corresponding to the plurality of warning time nodes based on the first orbit data and the second orbit data; Determining an initial time interval where the minimum relative distance between the spacecraft and the candidate space targets is located based on the relative distance change rates corresponding to the plurality of warning time nodes; Searching for a time interval where the minimum relative distance is located within the initial time interval until a time range of the search time interval is less than a preset duration; Judging whether the search time interval is the target time interval by using a kinematic screening method, where the target time interval is used to represent a time interval within the initial time interval where there may be a collision risk between the spacecraft and the candidate space targets.

2. The method according to claim 1, wherein Performing epoch and perigee - apogee altitude screening on the multiple space targets based on the first orbit data and the second orbit data to obtain candidate space targets, including: Screening the multiple space targets based on the epoch moments of the multiple space targets in the second orbit data to obtain at least one initial space target, where the at least one initial space target is used to represent a space target whose difference between the epoch moment in the TLE data and the current moment is less than a first preset threshold; Based on the perigee and apogee altitude screening conditions of the candidate space target, screen the at least one initial space target to obtain the candidate space target, where the perigee altitude and apogee altitude of the candidate space target satisfy the perigee and apogee altitude screening conditions of the candidate space target, and the perigee and apogee altitude screening conditions of the candidate space target are as follows: P0<A s +D&A0>P s -D; Wherein, P0 is the perigee altitude of the initial space target, and A s is the apogee altitude of the spacecraft, A0 is the apogee altitude of the initial space target, and P s is the perigee altitude of the spacecraft, and D is the screening threshold between the perigee and the apogee.

3. The method according to claim 1, wherein Based on the first orbit data and the second orbit data, determine the relative distance change rates corresponding to the multiple warning time nodes, including: Based on the first orbit data and the second orbit data, use the SGP4 model to calculate the first position and first velocity of the spacecraft corresponding to the multiple warning time nodes, and the second position and second velocity of the candidate space target corresponding to the multiple warning time nodes, and determine the relative distance change rates corresponding to the multiple warning time nodes, where the relative distance change rate is used to characterize the change rate of the relative distance between the spacecraft and the candidate space target.

4. The method according to claim 3, wherein Based on the first orbit data and the second orbit data, use the SGP4 model to calculate the first position and first velocity of the spacecraft corresponding to the multiple warning time nodes, and the second position and second velocity of the candidate space target corresponding to the multiple warning time nodes, and determine the relative distance change rates corresponding to the multiple warning time nodes, including: Among them, the is the first position corresponding to the multiple warning time nodes, the is the second position corresponding to the multiple warning time nodes, the is the relative position corresponding to the multiple warning time nodes, the is the first speed corresponding to the multiple warning time nodes, the is the second speed corresponding to the multiple warning time nodes, the is the relative speed corresponding to the multiple warning time nodes, ρ is the relative distance corresponding to the multiple warning time nodes, and the is the relative distance change rate corresponding to the multiple warning time nodes.

5. The method according to claim 1, wherein Based on the relative distance change rates corresponding to the multiple warning time nodes, determine the initial time interval where the relative distance minimum value between the spacecraft and the candidate space target is located, including: Obtain the first relative distance change rate corresponding to the first time node and the second relative distance change rate corresponding to the second time node among the multiple warning time nodes, where the first time node and the second time node are two adjacent time nodes among the multiple warning time nodes, and the first time node is earlier than the second time node; In response to the first relative distance change rate being less than the third preset threshold and the second relative distance change rate being greater than the third preset threshold, add the time interval corresponding to the first time node and the second time node to the initial time interval.

6. The method according to claim 1, wherein Within the initial time interval, search for the time interval where the relative distance minimum value is located until the time range of the search time interval is less than the preset duration, including: Within the initial time interval, iteratively search for the time interval where the relative distance minimum value is located based on the target golden section method until the time range of the search time interval is less than the preset duration.

7. The method according to claim 6, wherein Iteratively search for the time interval where the relative distance minimum value is located based on the target golden section method, including: Iteratively determine the search time interval within the initial time interval based on the minimum time node, maximum time node, starting time node, golden ratio time node, the first relative distance corresponding to the starting time node, and the second relative distance corresponding to the golden ratio time node until the duration of the search time interval is less than a preset duration. Herein, the starting time node is a node between the minimum time node and the maximum time node. At the first iteration, the starting time node is selected as the midpoint of the initial time interval, and the golden ratio time node is selected as the golden ratio point of the initial time interval; In response to the starting time node being less than the golden ratio time node and the first relative distance being less than the second relative distance, determine the time interval formed by the minimum time node and the golden ratio time node as the search time interval, and determine the starting time node as the starting time node for the next time search; In response to the starting time node being less than the golden ratio time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the starting time node and the maximum time node as the search time interval, and determine the golden ratio time node as the starting time node for the next time search; In response to the starting time node being greater than the golden ratio time node and the first relative distance being less than the second relative distance, determine the time interval formed by the golden ratio time node and the maximum time node as the search time interval, and determine the starting time node as the starting time node for the next time search; In response to the starting time node being greater than the golden ratio time node and the first relative distance being greater than the second relative distance, determine the time interval formed by the minimum time node and the starting time node as the search time interval, and determine the golden ratio time node as the starting time node for the next time search.

8. The method according to claim 1, wherein Use the kinematic screening method to determine whether the search time interval is the target time interval, including: Based on the duration of the search time interval, use the kinematic screening method to determine the relative distance threshold; Based on the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node in the search time interval, determine the smaller value between the relative distance corresponding to the minimum time node and the relative distance corresponding to the maximum time node to obtain the smaller relative distance value. Compare the smaller relative distance value with the relative distance threshold. In response to the smaller relative distance value being greater than the relative distance threshold, it is not necessary to solve for the minimum relative distance in the subsequent initial time interval. In the next time interval of the initial time interval, repeat the steps of determining the target time interval. In response to the smaller relative distance value being less than or equal to the relative distance threshold, determine the search time interval as the target time interval.

9. The method according to claim 1, characterized in that, Determine the minimum relative distance between the spacecraft and the candidate space target within the target time interval, and based on the minimum relative distance, determine the collision warning result between the spacecraft and the candidate space target, including: Within the target time interval, use the target golden section method to continue iteratively searching for the time interval where the minimum relative distance is located until the time interval between the time nodes of two adjacent golden section method samplings is less than the set threshold, and determine that the corresponding relative distance at this time is the minimum relative distance; Compare the minimum relative distance with the collision warning threshold; In response to the minimum relative distance being greater than the collision warning threshold, determine that the collision warning result is that there is no collision risk between the spacecraft and the candidate space target within the future time period; In response to the minimum relative distance being less than the collision warning threshold, determine that the collision warning result is that there is a collision risk between the spacecraft and the candidate space target within the future time period, and convert the minimum relative distance to the UNW coordinate system of the spacecraft to obtain multiple direction components; Match the multiple direction components with the pre-determined warning level threshold to obtain the collision warning level; Based on the collision warning level, determine whether to issue a warning message.

Images