Method and device for determining an evasion threshold, storage medium, electronic device

Abstract

The embodiment of the present disclosure provides a determination method and device for avoiding threshold, a storage medium and an electronic device in the field of aerospace engineering technology, which comprises the following steps: determining a dangerous intersection event set and a collision probability set of all satellites in a constellation and space debris within a preset time, wherein the collision probability set has the collision probability of each dangerous intersection event in the dangerous intersection event set; determining the target survival probability of the constellation after avoidance based on an initial avoidance threshold according to the dangerous intersection event set and the collision probability set; in the case that the target survival probability does not meet a preset condition, adjusting the initial avoidance threshold until the target survival probability of the constellation after avoidance based on the adjusted initial avoidance threshold meets the preset condition, and determining the adjusted initial avoidance threshold as the avoidance threshold of the constellation. The above method changes the avoidance decision from single risk avoidance to cumulative risk avoidance, which can guarantee the long-term safety of the mega constellation.

Description

Technical Field

[0001] This disclosure relates to the field of aerospace engineering technology, specifically to a method and apparatus for determining an avoidance threshold, a storage medium, and an electronic device. Background Technology

[0002] Currently, the low Earth orbit (LEO) space environment is becoming increasingly crowded, with a continuous increase in the amount of space debris, significantly raising the risk of spacecraft collisions. To ensure the safety of spacecraft in orbit, the internationally accepted practice mainly relies on two indicators: the probability of collision (POC) of a single rendezvous event and the closest approach distance (CAD), combined with the spacecraft's structural characteristics and orbital parameters, to set graded warning thresholds. However, with the large number of satellites in mega-constellations in LEO, this method is insufficient to guarantee the long-term safety of these giant constellations.

[0003] There is currently no effective solution to the problem of ensuring the long-term safety of giant constellations in related technologies.

[0004] Therefore, it is necessary to improve the relevant technology to overcome the aforementioned defects. Summary of the Invention

[0005] This disclosure provides a method and apparatus for determining an avoidance threshold, a storage medium, and an electronic device, to at least address the problem that related technologies struggle to ensure the long-term safety of mega-constellations.

[0006] According to one embodiment of this disclosure, a method for determining an avoidance threshold is provided, comprising: determining a set of dangerous encounter events and a set of collision probabilities of all satellites and space debris within a constellation within a preset time period, wherein the collision probability set contains the collision probability of each dangerous encounter event in the dangerous encounter event set; determining a target survival probability of the constellation after avoidance based on an initial avoidance threshold according to the dangerous encounter event set and the collision probability set, wherein the target survival probability is the calculated probability that the constellation will not collide within the preset time period; if the target survival probability does not meet a preset condition, adjusting the initial avoidance threshold until the target survival probability of the constellation after avoidance based on the adjusted initial avoidance threshold meets the preset condition, and determining the adjusted initial avoidance threshold as the avoidance threshold of the constellation.

[0007] In an exemplary embodiment, the method further includes: determining the initial avoidance threshold as the avoidance threshold of the constellation when the target survival probability meets the preset condition.

[0008] In an exemplary embodiment, determining the target survival probability of the constellation after avoidance based on an initial avoidance threshold, according to the set of dangerous encounter events and the set of collision probabilities, includes: determining a target dangerous encounter event set from the set of dangerous encounter events, wherein the dangerous encounter events in the target dangerous encounter event set are events in the set of dangerous encounter events whose collision probability is less than the initial avoidance threshold; and determining the target survival probability based on the collision probability of each dangerous encounter event in the target dangerous encounter event set.

[0009] In an exemplary embodiment, determining the target survival probability based on the collision probability of each dangerous intersection event in the target dangerous intersection event set includes: determining the target survival probability as the product of the non-collision probabilities of each dangerous intersection event in the target dangerous intersection event set, wherein the sum of the non-collision probability and the collision probability of each dangerous intersection event is 1.

[0010] In an exemplary embodiment, the method further includes: determining whether the target survival probability satisfies the preset condition by: determining the expected survival probability and allowable fault tolerance ratio of the constellation within the preset time period; determining an expected survival probability range based on the expected survival probability and the allowable fault tolerance ratio; determining that the target survival probability satisfies the preset condition if the target survival probability is within the expected survival probability range; and determining that the target survival probability does not satisfy the preset condition if the target survival probability is not within the expected survival probability range.

[0011] In an exemplary embodiment, determining the expected survival probability of the constellation within a preset time period includes: determining the expected cumulative collision probability of the constellation within the preset time period, wherein the cumulative collision probability is the total probability that the constellation will collide at least once within the preset time period; and determining the expected survival probability based on the cumulative collision probability, wherein the sum of the cumulative collision probability and the expected survival probability is 1.

[0012] In an exemplary embodiment, if the target survival probability does not meet the preset condition, the initial avoidance threshold is adjusted until the target survival probability of the constellation meets the preset condition after avoidance based on the adjusted initial avoidance threshold, and the adjusted initial avoidance threshold is determined as the avoidance threshold of the constellation. This includes: repeatedly executing the following steps until the avoidance threshold of the constellation is obtained, wherein, in the first instance of performing the following operations, the reference avoidance threshold is the initial avoidance threshold, the target avoidance threshold interval is a preset avoidance threshold interval, and the initial avoidance threshold is located within the preset avoidance threshold interval; re-determining the reference avoidance threshold within the preset avoidance threshold interval; determining the target survival probability of the constellation after avoidance based on the reference avoidance threshold according to the dangerous encounter event set and the collision probability set; and determining the reference avoidance threshold as the avoidance threshold of the constellation if the target survival probability meets the preset condition.

[0013] In an exemplary embodiment, re-determining the reference avoidance threshold within the preset avoidance threshold interval includes: when the target survival probability is less than the minimum value of the expected survival probability interval, updating the maximum value of the target avoidance threshold interval to the reference avoidance threshold; updating the reference avoidance threshold to the median value of the updated target avoidance threshold interval; when the target survival probability is greater than the maximum value of the expected survival probability interval, updating the minimum value of the target avoidance threshold interval to the reference avoidance threshold; and updating the reference avoidance threshold to the median value of the updated target avoidance threshold interval.

[0014] According to another embodiment of this disclosure, an apparatus for determining an avoidance threshold is provided, comprising: a first determining module, configured to determine a set of dangerous encounter events and a set of collision probabilities of all satellites and space debris within a constellation within a preset time period, wherein the collision probability set contains a collision probability for each dangerous encounter event in the set of dangerous encounter events; a second determining module, configured to determine a target survival probability of the constellation after avoidance based on an initial avoidance threshold according to the set of dangerous encounter events and the set of collision probabilities, wherein the target survival probability is a calculated probability that the constellation will not collide within the preset time period; and a third determining module, configured to adjust the initial avoidance threshold if the target survival probability does not meet a preset condition, until the target survival probability of the constellation after avoidance based on the adjusted initial avoidance threshold meets the preset condition, and to determine the adjusted initial avoidance threshold as the avoidance threshold of the constellation.

[0015] According to yet another embodiment of this disclosure, a computer-readable storage medium is also provided, wherein a computer program is stored therein, wherein the computer program is configured to perform the steps in any of the above method embodiments when it is run.

[0016] According to yet another embodiment of this disclosure, an electronic device is also provided, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0017] According to yet another embodiment of this disclosure, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps in any of the above method embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the architecture of a satellite communication system according to an embodiment of the present disclosure;

[0019] Figure 2 This is a flowchart (a) of a method for determining an avoidance threshold according to an embodiment of the present disclosure;

[0020] Figure 3 This is a flowchart (II) of a method for determining an avoidance threshold according to an embodiment of the present disclosure;

[0021] Figure 4 This is a structural block diagram of a threshold determination device according to an embodiment of the present disclosure. Detailed Implementation

[0022] The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings and examples.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] To better understand the method for determining the avoidance threshold disclosed in this disclosure, the satellite communication system to which this disclosure applies will be described first.

[0025] Please see Figure 1 , Figure 1 This is a schematic diagram of the architecture of a satellite communication system according to an embodiment of the present disclosure. The satellite communication system may include a satellite 101, a terminal 102, and a gateway station 103.

[0026] In this disclosure, satellite 101 is an entity used for transmitting or receiving signals. The embodiments of this disclosure do not limit the specific technologies or equipment used in the satellite.

[0027] In this disclosure, terminal 102 refers to a processing device within the satellite coverage beam range for communicating with a satellite. For example, the terminal can be a computer, mobile phone, control device, etc., equipped with satellite communication capabilities. This disclosure does not limit the specific technology or device form used in the terminal. It should be noted that... Figure 1 The example uses two terminal devices 102.

[0028] In one embodiment of this disclosure, gateway station 103 is connected to satellite 101.

[0029] In this embodiment, the gateway station 103 is a ground-based node in a satellite communication system used for transmitting and receiving data. This embodiment does not limit the specific technology or equipment form employed by the gateway station.

[0030] It should be noted that the method for determining the avoidance threshold in this embodiment can be executed by the terminal 102, and then, in the case of determining the avoidance threshold of the constellation, the satellites 101 in the constellation perform avoidance maneuvers according to the avoidance threshold.

[0031] It is understood that the satellite communication system described in this disclosure is for the purpose of more clearly illustrating the technical solutions of this disclosure, and does not constitute a limitation on the technical solutions provided in this disclosure. As those skilled in the art will know, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions provided in this disclosure are also applicable to similar technical problems.

[0032] To better understand, the collision warning strategies in related technologies are explained below:

[0033] 1) First Collision Warning Strategy: Every 24 hours, a complete intersection risk screening based on high-accuracy catalog data is conducted on all near-Earth and deep-space objects to form a risk concern list. Then, risk intersections on the concern list are screened every 8 hours. Table 1 below defines the basic warning service based on high-accuracy catalog data (HAC), and Table 2 defines the warning criteria for advanced warning services.

[0034] Table 1

[0035]

[0036] Table 2

[0037]

[0038] 2) Second collision warning strategy: A two-level collision warning strategy is adopted.

[0039] Orange alert: Collision probability ≥ (Error ellipsoid 1000m×200m×100m);

[0040] Red Alert: Collision probability ≥ (Error ellipsoid 1000m×200m×100m).

[0041] As can be seen from the above, the first collision warning strategy adopts a hierarchical warning strategy based on high-precision catalog data, setting different Time of Closest Approach (TCA) and distance thresholds for deep space and low Earth orbit, and activating a more stringent 10-second warning system in emergency situations. -4 Collision probability threshold triggers avoidance; the second collision warning strategy also adopts a similar dual-index system, with 3×10 -5 and 1×10 -4 As the basis for determining orange and red alerts.

[0042] However, the above methods only consider the risks brought about by a single dangerous encounter and cannot assess the remaining risks that still exist in long-term on-orbit operation after avoiding certain thresholds. In contrast, the satellites in a large low-orbit constellation are numerous, and the number of dangerous encounters is far greater than that of a single satellite. The cumulative effect of risks is obvious. Even if a single dangerous encounter does not exceed the threshold within a certain period of time, the collision risk of multiple encounters may exceed the threshold. In other words, the above methods are difficult to support long-term, stable on-orbit safe operation and maintenance.

[0043] This embodiment provides a method for determining the avoidance threshold to address the problem of ensuring the long-term safety of giant constellations. Figure 2 This is a flowchart (a) of a method for determining an avoidance threshold according to an embodiment of the present disclosure, as shown below. Figure 2 As shown, the process includes the following steps S202-S206:

[0044] Step S202: Determine the set of dangerous rendezvous events and the set of collision probabilities of all satellites and space debris within the constellation within a preset time period, wherein the collision probability set contains the collision probability of each dangerous rendezvous event in the set of dangerous rendezvous events;

[0045] In this embodiment, methods such as perigee-apogee screening, minimum distance between orbits screening, and time screening can be used to screen hazardous targets within the constellation. After screening hazardous targets, rendezvous calculation is performed, which calculates the closest time between two targets and their positional relationship. The algorithms used for rendezvous calculation include, but are not limited to, Newton's iteration method and the AN algorithm.

[0046] After performing rendezvous calculations, the collision probability between the two targets is calculated. It's important to note that the collision probability is a crucial criterion for assessing the likelihood of a collision during a space target rendezvous and is essential for spacecraft maneuvering and avoidance. In actual rendezvous calculations, errors arise from both observation and orbital extrapolation, resulting in errors in the position data of cataloged objects at any given moment. The actual position of the object is contained within an error ellipsoid. The collision probability is defined as the likelihood that space debris will enter a sphere of radius R centered on the spacecraft during a rendezvous (this sphere is called the safe zone). In other words, the collision probability is the probability that a satellite and debris will collide during a single rendezvous.

[0047] It should be noted that the calculation of the collision probability of space targets is generally based on the following assumptions:

[0048] 1) Given the position and velocity vectors of two targets in the inertial frame at a certain moment during their encounter, both targets in space are equivalent to spheres with known radii;

[0049] 2) During the encounter, both targets move at a constant linear velocity and there is no velocity uncertainty, so the position error ellipsoid remains unchanged during the encounter.

[0050] 3) The position errors of both targets follow a 3-dimensional normal distribution, which can be described by the distribution center and the position error covariance matrix.

[0051] A collision occurs when the distance between two targets is less than the sum of their equivalent radii. Therefore, the collision probability is defined as the probability that the minimum distance between two targets is less than the sum of their equivalent radii.

[0052] Step S204: Determine the target survival probability of the constellation after avoidance based on the set of dangerous encounter events and the set of collision probabilities, wherein the target survival probability is the calculated probability that the constellation does not collide within the preset time.

[0053] It should be noted that the survival probability is a concept introduced in this disclosure to assess the risk status of a constellation over a period of time. It is defined as the probability that, within a given timeframe, all satellites contained within the constellation will not collide with space debris.

[0054] In this embodiment, the target survival probability is a specific value of the survival probability.

[0055] Step S206: If the target survival probability does not meet the preset condition, adjust the initial avoidance threshold until the target survival probability of the constellation meets the preset condition after avoidance according to the adjusted initial avoidance threshold, and determine the adjusted initial avoidance threshold as the avoidance threshold of the constellation.

[0056] It should be noted that if the collision probability of a dangerous rendezvous event is greater than the avoidance threshold of the constellation, the satellite corresponding to the dangerous rendezvous event will perform an avoidance maneuver.

[0057] In an exemplary embodiment, if the target survival probability meets a preset condition, the initial avoidance threshold is determined as the avoidance threshold of the constellation.

[0058] Optionally, the preset conditions can be that the target survival probability is greater than a preset threshold or that the target survival probability is within a preset threshold range.

[0059] Optionally, if the target survival probability does not meet the preset conditions, the initial avoidance threshold can be adjusted iteratively using a bisection method. The survival probability is recalculated after each adjustment until convergence, and the avoidance threshold at the time of convergence is determined as the avoidance threshold of the constellation.

[0060] It should be noted that when the probability of a collision in any dangerous encounter exceeds the constellation's avoidance threshold, the corresponding satellite will be automatically triggered to perform avoidance maneuvers, thereby significantly improving the long-term survivability of the giant constellation.

[0061] The above steps determine the avoidance threshold of a constellation based on the probability that no collision occurs within the preset time. This upgrades the risk assessment of a single encounter to a cumulative risk assessment. By iteratively adjusting the avoidance threshold, it ensures that the target survival probability of the constellation meets the preset conditions after avoidance based on the avoidance threshold. This transforms the avoidance decision from single risk avoidance to cumulative risk avoidance, which can guarantee the long-term safety of giant constellations. This solves the problem that existing early warning methods ignore cumulative risks and are unable to guarantee the long-term safety of giant constellations.

[0062] In an exemplary embodiment, determining the target survival probability of the constellation after avoidance based on an initial avoidance threshold, according to the set of dangerous encounter events and the set of collision probabilities, includes: determining a target dangerous encounter event set from the set of dangerous encounter events, wherein the dangerous encounter events in the target dangerous encounter event set are events in the set of dangerous encounter events whose collision probability is less than the initial avoidance threshold; and determining the target survival probability based on the collision probability of each dangerous encounter event in the target dangerous encounter event set.

[0063] It should be noted that in this embodiment, since the satellites corresponding to events with a collision probability higher than the initial avoidance threshold are subjected to avoidance maneuvers and become risk-free, in order to accurately determine the target survival probability of the constellation after avoidance, it is necessary to select events with a collision probability lower than the initial avoidance threshold from the set of dangerous rendezvous events to form a target dangerous rendezvous event set, and then determine the target survival probability based on the target dangerous rendezvous event set.

[0064] In an exemplary embodiment, determining the target survival probability based on the collision probability of each dangerous intersection event in the target dangerous intersection event set includes: determining the target survival probability as the product of the non-collision probabilities of each dangerous intersection event in the target dangerous intersection event set, wherein the sum of the non-collision probability and the collision probability of each dangerous intersection event is 1.

[0065] In other words, the survival probability of the target can be calculated using the following formula: ;in, Let n be the survival probability of the target, and n be the number of dangerous intersection events in the set of dangerous intersection events of the target. Let be the collision probability of the i-th dangerous intersection event in the set of target dangerous intersection events.

[0066] It should be noted that the above formula is based on the assumption of statistical independence between events, treating each encounter that does not trigger avoidance as a low-probability, collision-free trial, and determining the survival probability of the constellation within a preset time by multiplying and accumulating the results.

[0067] In an exemplary embodiment, the method further includes: determining whether the target survival probability satisfies the preset condition through the following steps S11-S14:

[0068] Step S11: Determine the expected survival probability and allowable fault tolerance ratio of the constellation within the preset time period;

[0069] It should be noted that the expected survival probability is the minimum expected survival probability within a preset time period. For example, the minimum acceptable survival probability for a constellation within a preset period (such as 10 years) is 99%. Optionally, the allowable fault tolerance ratio is a preset value, which can be determined based on the ratio of the difference between the survival probability after avoidance and the expected survival probability to the expected survival probability.

[0070] Step S12: Determine the expected survival probability range based on the expected survival probability and the allowable fault tolerance ratio;

[0071] For example, with an expected survival probability of 99% and an allowable fault tolerance ratio of 0.01, the expected survival probability range is [0.9-0.9]. 0.01, 0.9 + 0.9 [0.01], which is [0.891, 0.909].

[0072] Step S13: If the target survival probability is within the expected survival probability range, determine that the target survival probability satisfies the preset condition;

[0073] Step S14: If the target survival probability is not within the expected survival probability range, determine that the target survival probability does not meet the preset condition.

[0074] It should be noted that if the calculated target survival probability falls within the expected survival probability range, it indicates that the current avoidance threshold can effectively control the accumulated risk. If the target survival probability is not within the expected survival probability range, it means that the collision risk is too high or too low, and the avoidance threshold needs to be readjusted and reassessed.

[0075] In an exemplary embodiment, determining the expected survival probability of the constellation within a preset time period includes: determining the expected cumulative collision probability of the constellation within the preset time period, wherein the cumulative collision probability is the total probability that the constellation will collide at least once within the preset time period; and determining the expected survival probability based on the cumulative collision probability, wherein the sum of the cumulative collision probability and the expected survival probability is 1.

[0076] It should be noted that cumulative collision probability is another concept introduced in this disclosure, referring to the total collision threat a constellation faces within a certain period of time. The cumulative collision probability can be calculated from the constellation's survival probability, using the following formula: ;in, To accumulate collision probability, The survival probability of a constellation.

[0077] In an exemplary embodiment, if the target survival probability does not meet the preset condition, the initial avoidance threshold is adjusted until the target survival probability of the constellation meets the preset condition after avoidance based on the adjusted initial avoidance threshold, and the adjusted initial avoidance threshold is determined as the avoidance threshold of the constellation. This includes: repeatedly executing the following steps S21-S23 until the avoidance threshold of the constellation is obtained, wherein, when performing the following operation for the first time, the reference avoidance threshold is the initial avoidance threshold, the target avoidance threshold interval is a preset avoidance threshold interval, and the initial avoidance threshold is located within the preset avoidance threshold interval.

[0078] Step S21: Re-determine the reference avoidance threshold within the preset avoidance threshold range;

[0079] Optionally, a value can be randomly selected from the preset avoidance threshold range as the reference avoidance threshold, or a binary search method can be used to redetermine the reference avoidance threshold from the preset avoidance threshold range.

[0080] In an exemplary embodiment, step S21 can be implemented as follows: if the target survival probability is less than the minimum value of the expected survival probability interval, update the maximum value of the target avoidance threshold interval to a reference avoidance threshold; update the reference avoidance threshold to the median value of the updated target avoidance threshold interval; if the target survival probability is greater than the maximum value of the expected survival probability interval, update the minimum value of the target avoidance threshold interval to a reference avoidance threshold; update the reference avoidance threshold to the median value of the updated target avoidance threshold interval.

[0081] For example, taking the expected survival probability range of 10 years [98.5%, 99.5%] as an example, the initial avoidance threshold range is set to [0, The initial reference avoidance threshold is taken as the median value of 5 × If the calculated survival probability of the target is 98.0% (lower than 98.5%), it indicates a high risk, and the threshold needs to be lowered to increase the number of avoidance attempts and reduce the cumulative collision probability; thus, the upper limit of the interval should be increased from... Updated to 5× The updated target avoidance threshold range is [0, 5×]. ], and use the value in the middle as the new reference avoidance threshold.

[0082] If the target survival probability is 99.8% (higher than 99.5%), it indicates that the threshold is too strict, leading to excessive avoidance. In this case, the lower limit of the interval is updated to the current reference value, and the updated target avoidance threshold interval is [5× , The midpoint of the interval is used as the new reference avoidance threshold.

[0083] Using the above dichotomy method, the reference avoidance threshold gradually converges to the optimal value that makes the target's survival probability fall into [98.5%, 99.5%].

[0084] Step S22: Determine the target survival probability of the constellation after avoidance based on the reference avoidance threshold according to the set of dangerous encounter events and the set of collision probabilities;

[0085] It should be noted that the method for determining the target survival probability of the constellation after avoidance based on the reference avoidance threshold is the same as the method for determining the target survival probability of the constellation after avoidance based on the initial avoidance threshold, and will not be repeated here.

[0086] Step S23: If the target survival probability meets the preset condition, the reference avoidance threshold is determined as the avoidance threshold of the constellation.

[0087] It should be noted that, if the target survival probability meets the preset conditions, the above steps S21-S23 are executed again until the avoidance threshold of the constellation is determined.

[0088] It should be noted that in this embodiment, the avoidance threshold is dynamically converged by the binary search method, which accurately balances security and resource consumption. Under the premise of ensuring that the survival probability of the constellation within the preset time is controllable, excessive avoidance is avoided, and the threshold is adaptively optimized.

[0089] To better understand, the following example is provided:

[0090] The selection of the early warning and avoidance threshold (i.e., the avoidance threshold for the aforementioned constellations) depends on the cumulative collision probability of the desired low-Earth orbit mega-constellations. To ensure the continuous and long-term safety of the constellations in orbit, the cumulative collision probability of the mega-constellations needs to be controlled within a reasonable range. The calculation process for the early warning and avoidance threshold is as follows: Figure 3 As shown.

[0091] Step 1: Input the expected cumulative collision probability of the constellation over a period of time.

[0092] Step 2: Calculate the expected survival probability of the constellation. For example: Assuming that the expected cumulative collision probability of the constellation over 10 years is no higher than 1%, then the survival probability of the constellation over 10 years is no less than 99%. If the warning period is 3 days, the survival probability over 3 days can be calculated to be no less than 99.999174%.

[0093] Step 3: Calculate the risk of rendezvous for all satellites in the constellation during this time period; for details on the calculation method, please refer to step S202 above.

[0094] Step 4: Set the initial value and range of the avoidance threshold. Generally, the avoidance threshold should not exceed 10. -4 Therefore, the avoidance threshold range can be set to 0 to 10. -4 The initial value is 5×10 -5 .

[0095] Step 5: Calculate the survival probability of the constellation after avoiding the current threshold:

[0096] Step Six: Determine if the survival probability meets the requirements (this can be determined by calculating whether the ratio of the difference between the survival probability after avoidance and the expected survival probability to the desired survival probability is lower than the set threshold). If the requirements are not met, adjust the collision probability threshold using the bisection method, go to Step Five, and iterate until the survival probability meets the requirements.

[0097] For example: Assuming the expected survival probability is 0.9, the ratio of the difference between the survival probability after avoidance and the expected survival probability to the expected survival probability, then the acceptable range for the survival probability after avoidance is [0.9-0.9]. 0.01, 0.9 + 0.9 [0.01], which is [0.891, 0.909].

[0098] When the survival probability after avoidance is less than 0.891, it indicates that the current avoidance threshold is too high. The maximum value of the avoidance threshold range is adjusted to the current threshold, the minimum value remains unchanged, and the avoidance threshold is adjusted to the median value of the changed range.

[0099] When the survival probability after avoidance is greater than 0.909, it indicates that the current avoidance threshold is too low. The minimum value of the avoidance threshold range is adjusted to the current threshold, while the maximum value remains unchanged. The avoidance threshold is then adjusted to the median of the changed range. Then, proceed to step five to continue iterating until the survival probability after avoidance falls into a range that meets the requirements.

[0100] It should be noted that this disclosure establishes an assessment method to ensure the long-term safe operation of constellation satellites. This method integrates traditional risk rendezvous calculation methods and, through iterative solutions, determines the collision avoidance threshold for the long-term safe operation of the constellation.

[0101] To better understand, the following explanation is provided in conjunction with specific embodiments:

[0102] The TLE elements of on-orbit space debris at a certain time (December 6, 2025) were selected as the background target. A low-Earth orbit giant constellation with an orbital altitude of about 500km, an orbital inclination of 55°, and containing 3600 stars was selected as the evaluation target. The dangerous encounters between the constellation and the background debris within 3 days were simulated and calculated.

[0103] For different forecast errors, the rendezvous situations (within 10km) are shown in Table 3 below:

[0104] Table 3

[0105]

[0106] The risk results over 10 years, derived from the above results, are shown in Table 4 below.

[0107] Table 4

[0108]

[0109] As shown above, for low-Earth orbit giant constellations, to ensure a survival probability of over 97% within 10 years, it is necessary to avoid prediction errors on the order of hundreds of meters, while the avoidance threshold should be ≤10. -6 .

[0110] Currently, the number of Starlink satellites at an orbital altitude of 550 kilometers is similar to the simulation example above, and their avoidance criteria are: when the probability of collision is greater than... 10 -7 When the probability of a collision is 0.03%, the satellite will perform an evasive maneuver, which matches the simulation results of this method.

[0111] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0112] This embodiment also provides a threshold determination device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0113] Figure 4 This is a structural block diagram of an avoidance threshold determination device according to an embodiment of the present disclosure, such as... Figure 4 As shown, the device includes:

[0114] The first determining module 402 is used to determine the set of dangerous rendezvous events and the set of collision probabilities of all satellites and space debris in the constellation within a preset time period, wherein the set of collision probabilities contains the collision probability of each dangerous rendezvous event in the set of dangerous rendezvous events;

[0115] The second determining module 404 is used to determine the target survival probability of the constellation after avoidance based on the set of dangerous encounter events and the set of collision probabilities, wherein the target survival probability is the calculated probability that the constellation does not collide within the preset time.

[0116] The third determining module 406 is used to adjust the initial avoidance threshold when the target survival probability does not meet the preset condition, until the target survival probability of the constellation meets the preset condition after avoidance according to the adjusted initial avoidance threshold, and to determine the adjusted initial avoidance threshold as the avoidance threshold of the constellation.

[0117] The aforementioned device determines the avoidance threshold of a constellation based on the probability that no collision occurs within the preset time. It upgrades the risk assessment of a single encounter to a cumulative risk assessment. By iteratively adjusting the avoidance threshold, it ensures that the target survival probability of the constellation meets the preset conditions after avoidance based on the avoidance threshold. This transforms the avoidance decision from single risk avoidance to cumulative risk avoidance, which can guarantee the long-term safety of giant constellations. This solves the problem that existing early warning methods ignore cumulative risks and are unable to guarantee the long-term safety of giant constellations.

[0118] In an exemplary embodiment, the third determining module 406 is further configured to determine the initial avoidance threshold as the avoidance threshold of the constellation if the target survival probability satisfies the preset condition.

[0119] In an exemplary embodiment, the second determining module 404 is further configured to determine a target dangerous intersection event set from the dangerous intersection event set, wherein the dangerous intersection events in the target dangerous intersection event set are events in the dangerous intersection event set whose collision probability is less than the initial avoidance threshold; and to determine the target survival probability based on the collision probability of each dangerous intersection event in the target dangerous intersection event set.

[0120] In an exemplary embodiment, the second determining module 404 is further configured to determine the target survival probability as the product of the non-collision probabilities of each dangerous intersection event in the target dangerous intersection event set, wherein the sum of the non-collision probability of each dangerous intersection event and the collision probability of each dangerous intersection event is 1.

[0121] In an exemplary embodiment, the third determining module 406 is further configured to determine whether the target survival probability satisfies the preset condition by: determining the expected survival probability and the allowable fault tolerance ratio of the constellation within the preset time period; determining the expected survival probability range based on the expected survival probability and the allowable fault tolerance ratio; determining that the target survival probability satisfies the preset condition if the target survival probability is within the expected survival probability range; and determining that the target survival probability does not satisfy the preset condition if the target survival probability is not within the expected survival probability range.

[0122] In an exemplary embodiment, the third determining module 406 is further configured to determine the expected cumulative collision probability of the constellation within the preset time period, wherein the cumulative collision probability is the total probability that the constellation will collide at least once within the preset time period; and to determine the expected survival probability based on the cumulative collision probability, wherein the sum of the cumulative collision probability and the expected survival probability is 1.

[0123] In an exemplary embodiment, the third determining module 406 is further configured to repeatedly execute the following steps until the avoidance threshold of the constellation is obtained, wherein, when performing the following operations for the first time, the reference avoidance threshold is the initial avoidance threshold, the target avoidance threshold interval is a preset avoidance threshold interval, and the initial avoidance threshold is located within the preset avoidance threshold interval: re-determine the reference avoidance threshold within the preset avoidance threshold interval; determine the target survival probability of the constellation after avoidance based on the reference avoidance threshold according to the dangerous encounter event set and the collision probability set; and determine the reference avoidance threshold as the avoidance threshold of the constellation if the target survival probability meets the preset condition.

[0124] In an exemplary embodiment, the third determining module 406 is further configured to: update the maximum value of the target avoidance threshold interval to a reference avoidance threshold when the target survival probability is less than the minimum value of the expected survival probability interval; update the reference avoidance threshold to the median value of the updated target avoidance threshold interval; update the minimum value of the target avoidance threshold interval to a reference avoidance threshold when the target survival probability is greater than the maximum value of the expected survival probability interval; and update the reference avoidance threshold to the median value of the updated target avoidance threshold interval.

[0125] Embodiments of this disclosure also provide a computer-readable storage medium storing a computer program configured to perform the steps in any of the above method embodiments when executed.

[0126] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk.

[0127] Embodiments of this disclosure also provide an electronic device including a memory and a processor, the memory storing a computer program and the processor being configured to run the computer program to perform the steps in any of the above method embodiments.

[0128] In one exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0129] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0130] Embodiments of this disclosure also provide a computer program product, which includes a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0131] Embodiments of this disclosure also provide another computer program product, including a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0132] The embodiments described herein also provide a computer program that includes computer instructions stored in a computer-readable storage medium; a processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps in any of the above method embodiments.

[0133] It is obvious to those skilled in the art that the modules or steps of this disclosure described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this disclosure is not limited to any particular combination of hardware and software.

[0134] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for determining an avoidance threshold, characterized in that, include: Determine the set of dangerous encounter events and the set of collision probabilities of all satellites and space debris within a constellation within a preset time period, wherein the set of collision probabilities contains the collision probability of each dangerous encounter event in the set of dangerous encounter events; The target survival probability of the constellation after avoidance based on the set of dangerous encounter events and the set of collision probabilities is determined, wherein the target survival probability is the calculated probability that the constellation does not collide within the preset time. If the target survival probability does not meet the preset conditions, the initial avoidance threshold is adjusted until the target survival probability of the constellation meets the preset conditions after avoidance based on the adjusted initial avoidance threshold, and the adjusted initial avoidance threshold is determined as the avoidance threshold of the constellation. The method further includes: determining whether the target survival probability meets the preset condition by: determining the expected survival probability and allowable fault tolerance ratio of the constellation within the preset time period; determining the expected survival probability range based on the expected survival probability and the allowable fault tolerance ratio; determining that the target survival probability meets the preset condition if the target survival probability is within the expected survival probability range; and determining that the target survival probability does not meet the preset condition if the target survival probability is not within the expected survival probability range. Where the target survival probability does not meet the preset condition, the initial avoidance threshold is adjusted until the target survival probability of the constellation meets the preset condition after avoidance based on the adjusted initial avoidance threshold, and the adjusted initial avoidance threshold is determined as the avoidance threshold of the constellation. This includes: repeatedly executing the following steps until the avoidance threshold of the constellation is obtained, wherein, when performing the following operations for the first time, the reference avoidance threshold is the initial avoidance threshold, the target avoidance threshold interval is a preset avoidance threshold interval, and the initial avoidance threshold is located within the preset avoidance threshold interval: re-determining the reference avoidance threshold within the preset avoidance threshold interval; determining the target survival probability of the constellation after avoidance based on the reference avoidance threshold according to the dangerous encounter event set and the collision probability set; and determining the reference avoidance threshold as the avoidance threshold of the constellation when the target survival probability meets the preset condition.

2. The method according to claim 1, characterized in that, The method further includes: If the target survival probability meets the preset condition, the initial avoidance threshold is determined as the avoidance threshold of the constellation.

3. The method according to claim 1, characterized in that, Based on the set of dangerous encounter events and the set of collision probabilities, the target survival probability of the constellation after avoidance based on the initial avoidance threshold is determined, including: A target set of dangerous encounter events is determined from the set of dangerous encounter events, wherein the dangerous encounter events in the target set of dangerous encounter events are those with a collision probability less than the initial avoidance threshold. The survival probability of the target is determined based on the collision probability of each dangerous encounter event in the set of dangerous encounter events.

4. The method according to claim 3, characterized in that, Determining the survival probability of the target based on the collision probability of each dangerous encounter event in the set of dangerous encounter events includes: The target survival probability is determined by multiplying the non-collision probability of each dangerous intersection event in the set of target dangerous intersection events, wherein the sum of the non-collision probability and the collision probability of each dangerous intersection event is 1.

5. The method according to claim 1, characterized in that, Determining the expected survival probability of the constellation within the preset time period includes: Determine the expected cumulative collision probability of the constellation within the preset time period, wherein the cumulative collision probability is the total probability that the constellation will collide at least once within the preset time period; The expected survival probability is determined based on the cumulative collision probability, wherein the sum of the cumulative collision probability and the expected survival probability is 1.

6. The method according to claim 1, characterized in that, Redetermine the reference avoidance threshold within the preset avoidance threshold range, including: If the target survival probability is less than the minimum value of the expected survival probability interval, the maximum value of the target avoidance threshold interval is updated to the reference avoidance threshold; the reference avoidance threshold is updated to the median value of the updated target avoidance threshold interval. If the target survival probability is greater than the maximum value of the expected survival probability interval, the minimum value of the target avoidance threshold interval is updated to the reference avoidance threshold; the reference avoidance threshold is updated to the median value of the updated target avoidance threshold interval.

7. A device for determining an avoidance threshold, characterized in that, include: The first determining module is used to determine the set of dangerous rendezvous events and the set of collision probabilities of all satellites and space debris within the constellation within a preset time period, wherein the set of collision probabilities contains the collision probability of each dangerous rendezvous event in the set of dangerous rendezvous events; The second determining module is used to determine the target survival probability of the constellation after avoidance based on the set of dangerous encounter events and the set of collision probabilities, wherein the target survival probability is the calculated probability that the constellation does not collide within the preset time. The third determining module is used to adjust the initial avoidance threshold when the target survival probability does not meet the preset conditions, until the target survival probability of the constellation meets the preset conditions after avoidance according to the adjusted initial avoidance threshold, and to determine the adjusted initial avoidance threshold as the avoidance threshold of the constellation. The third determining module is further configured to determine whether the target survival probability meets the preset condition by: determining the expected survival probability and allowable fault tolerance ratio of the constellation within the preset time period; determining the expected survival probability range based on the expected survival probability and the allowable fault tolerance ratio; determining that the target survival probability meets the preset condition if the target survival probability is within the expected survival probability range; and determining that the target survival probability does not meet the preset condition if the target survival probability is not within the expected survival probability range. The third determining module is further configured to repeatedly execute the following steps until the avoidance threshold of the constellation is obtained. Specifically, when performing the following operations for the first time, the reference avoidance threshold is the initial avoidance threshold, and the target avoidance threshold range is a preset avoidance threshold range. The initial avoidance threshold is located within the preset avoidance threshold range: a reference avoidance threshold is redefined within the preset avoidance threshold range; the target survival probability of the constellation after avoidance based on the reference avoidance threshold is determined according to the dangerous encounter event set and the collision probability set; and if the target survival probability satisfies the preset condition, the reference avoidance threshold is determined as the avoidance threshold of the constellation.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the method described in any one of claims 1 to 6.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in any one of claims 1 to 6.

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