Asteroid Bias Impact Accuracy Assessment Method and System

Abstract

This invention provides a method and system for evaluating the accuracy of asteroid offset impacts, comprising: Step 1: conducting an offset impact during the first rendezvous in an asteroid impact mission; Step 2: evaluating the lateral impact accuracy using a ranging sensor on the impactor; Step 3: evaluating the longitudinal impact accuracy using an optical image inversion method via an optical navigation sensor on the impactor; Step 4: comprehensively evaluating the offset impact accuracy based on the lateral and longitudinal impact accuracies. This invention can meet the needs of future asteroid defense missions, providing a good technical means for evaluating offset impact accuracy and possessing engineering application value. To ensure successful target impact, high-speed impact flight drills can be conducted via offset impacts before the rendezvous and impact of the target, allowing for on-orbit assessment of impact accuracy and adjustment of guidance and control parameters, thereby ensuring successful target impact and guaranteeing impact accuracy.

Description

Technical Field

[0001] This invention relates to the field of spacecraft technology, and more specifically, to a method and system for assessing the accuracy of asteroid offset impacts. Background Technology

[0002] Near-Earth objects (NEOs) are celestial bodies near Earth's orbit, including NEOs, comets, meteoroids, and artificial objects. They are "fossils" from the formation and early evolution of the solar system. Their orbital distribution and physicochemical properties reflect the early state of matter in the solar system and the very early stages of planetary formation. They also contribute to shaping Earth's geological features and habitable conditions through impacts, making them a key, hot, and cutting-edge research subject in astronomy and planetary science, and a widely watched target in deep space exploration. NEOs may collide with Earth; they are dim, widely distributed, and difficult to detect. Their orbits are easily altered by the gravitational pull of larger planets, and their impacts on Earth are often sudden. NEO impacts on Earth are a matter of human survival and safety, representing a long-term common threat to all humanity.

[0003] Patent document CN106428654A discloses a small, split-type survivable deep space impactor, which includes a front body and a rear body connected by a connecting cable. The front body and the rear body are connected as one unit before impact and separate after impact, which satisfies the requirement of penetrating into the interior of the target and surviving. However, this method is a deep space impactor design method and does not involve impact accuracy assessment.

[0004] Patent document CN106709138A discloses a method for designing impactor buffers based on mission constraints. It combines four-level buffering methods—shape, airbag, crushing, and potting—to meet the overload resistance requirements of components in the electronics compartment at the tail of the impactor. However, this method is a deep-space impactor buffer design method.

[0005] Patent document CN106394942A discloses a deep space impact buffer airbag constructed from a connecting device, an inflation device, a deployment device, an airbag, and a flexible solar cell, but this method is a method for constructing a deep space impact buffer airbag.

[0006] The paper, "Study on Penetration Test of a Deep Space Impactor," simulated the penetration process of a deep space impactor into a celestial body through ground-based experiments, obtaining data on the penetration depth, damage, and overload of the impactor at different velocities. However, this paper describes a ground-based deep space impact test.

[0007] The paper "Design and Analysis of Terminal Guidance Laws for Deep Space Impact Detection" designs several terminal guidance laws that meet the requirements of accuracy and fuel consumption, taking into account the characteristics of small celestial body impacts. It analyzes the influence of various error sources on the guidance accuracy of the guidance law. However, this paper is a study on terminal guidance laws for deep space impacts and does not involve impact accuracy assessment. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for evaluating the accuracy of asteroid offset impacts.

[0009] The asteroid offset impact accuracy assessment method provided by the present invention includes:

[0010] Step 1: Utilize the opportunity of the first encounter in an asteroid impact mission to conduct an offset impact;

[0011] Step 2: Evaluate the lateral impact accuracy using the range sensor on the impactor;

[0012] Step 3: Evaluate the longitudinal impact accuracy using optical image inversion via the optical navigation sensor on the impactor;

[0013] Step 4: Evaluate the offset impact accuracy based on the lateral impact accuracy and the longitudinal impact accuracy.

[0014] Preferably, the asteroid impact mission adopts a two-rendezvous-one-impact scheme, using the opportunity of the first rendezvous to conduct high-speed impact flight drills, assess impact accuracy in orbit and adjust guidance and control parameters, thereby ensuring the successful impact of the target during the second rendezvous;

[0015] A range sensor is installed on the impactor to measure the relative distance to the asteroid and to invert the lateral accuracy when passing through the virtual impact point.

[0016] An optical navigation sensor is installed on the impactor. The navigation sensor is calibrated before the biased impact. Based on the asteroid's optical image, the longitudinal accuracy when passing through the virtual impact point is inverted.

[0017] Preferably, based on multiple distance measurements from the ranging sensor before and after the rendezvous, , Let n be the total number of intersections, and satisfy the following theoretical function: ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function: ;in, This refers to the collision time between the impactors; This is the collision distance between the impactors;

[0018] Based on this, the closest encounter distance of the impactor can be estimated. Therefore, the lateral impact accuracy is: ,in, This represents the lateral distance from the theoretical aiming point.

[0019] Preferably, based on multiple imaging information from the optical navigation sensor before and after rendezvous, the asteroid image is processed using the gray-scale centroid method to calculate the centroid position of the asteroid image. The expression is:

[0020] ,

[0021] In the formula: represents the brightness value of the corresponding pixel; m and n are the number of pixels in the navigation sensor; ;

[0022] The imaging data of all navigation sensors were collected within the time period. The position of the asteroid centroid in the image was extracted. The long-period variation law of the asteroid centroid in the image was fitted to obtain the long-period variation law between the navigation sensor and the star sensor.

[0023] The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is:

[0024]

[0025] In the formula: Focal length of the navigation sensor; This represents the components of the relative position vector in the camera imaging coordinate system.

[0026] Preferably, the overall offset impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is:

[0027] .

[0028] The asteroid bias impact accuracy assessment system provided by the present invention includes:

[0029] Module M1: To conduct an offset impact during the first rendezvous in an asteroid impact mission;

[0030] Module M2: Evaluates lateral impact accuracy using a range sensor on the impactor;

[0031] Module M3: Uses optical image inversion to evaluate longitudinal impact accuracy via an optical navigation sensor on the impactor;

[0032] Module M4: Evaluates offset impact accuracy based on both lateral and longitudinal impact accuracy.

[0033] Preferably, the asteroid impact mission adopts a two-rendezvous-one-impact scheme, using the opportunity of the first rendezvous to conduct high-speed impact flight drills, assess impact accuracy in orbit and adjust guidance and control parameters, thereby ensuring the successful impact of the target during the second rendezvous;

[0034] A range sensor is installed on the impactor to measure the relative distance to the asteroid and to invert the lateral accuracy when passing through the virtual impact point.

[0035] An optical navigation sensor is installed on the impactor. The navigation sensor is calibrated before the biased impact. Based on the asteroid's optical image, the longitudinal accuracy when passing through the virtual impact point is inverted.

[0036] Preferably, based on multiple distance measurements from the ranging sensor before and after the rendezvous, , Let n be the total number of intersections, and satisfy the following theoretical function: ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function: ;in, This refers to the collision time between the impactors; This is the collision distance between the impactors;

[0037] Based on this, the closest encounter distance of the impactor can be estimated. Therefore, the lateral impact accuracy is: ,in, This represents the lateral distance from the theoretical aiming point.

[0038] Preferably, based on multiple imaging information from the optical navigation sensor before and after rendezvous, the asteroid image is processed using the gray-scale centroid method to calculate the centroid position of the asteroid image. The expression is:

[0039] ,

[0040] In the formula: represents the brightness value of the corresponding pixel; m and n are the number of pixels in the navigation sensor; ;

[0041] The imaging data of all navigation sensors were collected within the time period. The position of the asteroid centroid in the image was extracted. The long-period variation law of the asteroid centroid in the image was fitted to obtain the long-period variation law between the navigation sensor and the star sensor.

[0042] The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is:

[0043]

[0044] In the formula: Focal length of the navigation sensor; This represents the components of the relative position vector in the camera imaging coordinate system.

[0045] Preferably, the overall offset impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is:

[0046] .

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] This invention provides a method for evaluating the accuracy of asteroid offset impacts, which can meet the needs of future asteroid defense missions. It provides a good technical means for evaluating the accuracy of offset impacts and has engineering application value. In order to ensure successful impact on the target, high-speed impact flight drills can be conducted through offset impacts before rendezvous and impacting the target. The impact accuracy can be evaluated in orbit and the guidance and control parameters can be adjusted to ensure successful impact on the target and guarantee the impact accuracy. Attached Figure Description

[0049] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0050] Figure 1 This is a schematic diagram of the lateral impact accuracy evaluation of the present invention;

[0051] Figure 2 This is a schematic diagram of the longitudinal impact accuracy evaluation of the present invention;

[0052] Figure 3 This is a flowchart of the asteroid bias impact accuracy assessment method of the present invention. Detailed Implementation

[0053] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0054] Example 1

[0055] like Figure 3This invention provides a method for evaluating the accuracy of asteroid offset impacts, and the algorithm is illustrated as follows: Figure 1 , Figure 2 As shown, the specific steps include:

[0056] Step 1: The asteroid impact mission will take advantage of the first encounter to conduct an offset impact;

[0057] Step 2: The impactor assesses the lateral impact accuracy using a range sensor;

[0058] Step 3: The impactor uses an optical navigation sensor to evaluate the longitudinal impact accuracy by optical image inversion. The navigation sensor needs to be calibrated before the offset impact.

[0059] Step 4: Evaluate the offset impact accuracy based on the lateral impact accuracy and the longitudinal impact accuracy.

[0060] The asteroid impact mission employs a two-rendezvous-one-impact strategy. The first rendezvous will be used for high-speed impact flight simulation, allowing for on-orbit assessment of impact accuracy and adjustment of guidance and control parameters to ensure a successful impact during the second rendezvous. To assess the accuracy of the impact simulation, the impactor needs to be equipped with a range sensor to measure the relative distance to the asteroid, facilitating the inversion of lateral accuracy at the virtual impact point. Similarly, an optical navigation sensor, based on optical images of the asteroid, will be used to invert longitudinal accuracy at the virtual impact point.

[0061] Based on multiple distance measurements from the distance sensor before and after the rendezvous point and satisfy the following theoretical functions ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function, which is expressed as: Based on this, the closest rendezvous distance of the impactor can be estimated. Assuming the lateral distance of the theoretical aiming point is Therefore, the lateral impact accuracy can be obtained as: .

[0062] Based on multiple imaging data from the optical navigation sensor before and after rendezvous, the centroid position of the asteroid image was calculated using the gray-scale centroid method. The expression is:

[0063] ,

[0064] In the formula: is the brightness value of the corresponding pixel; m and n are the number of pixels of the navigation sensor.

[0065] Considering the impactor's exposure to complex thermal environments and structural deformations in orbit, the navigation sensor and star sensor exhibit long-period deformation. By acquiring imaging data from all navigation sensors within a given timeframe, extracting the asteroid's centroid position from the images, and fitting the long-period variation pattern of the asteroid's centroid in the images, the long-period variation pattern between the navigation sensor and the star sensor can be obtained.

[0066] The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is: In the formula: f is the focal length of the navigation sensor; L is the component of the relative position vector in the camera imaging coordinate system.

[0067] Overall bias impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is: .

[0068] Example 2

[0069] The present invention also provides an asteroid bias impact accuracy assessment system, which can be implemented by executing the process steps of the asteroid bias impact accuracy assessment method. That is, those skilled in the art can understand the asteroid bias impact accuracy assessment method as a preferred embodiment of the asteroid bias impact accuracy assessment system.

[0070] The asteroid offset impact accuracy evaluation system provided by the present invention includes: module M1: performing offset impact during the first rendezvous in an asteroid impact mission; module M2: evaluating lateral impact accuracy using a ranging sensor on the impactor; module M3: evaluating longitudinal impact accuracy using an optical image inversion method via an optical navigation sensor on the impactor; and module M4: comprehensively evaluating offset impact accuracy based on both lateral and longitudinal impact accuracy.

[0071] The asteroid impact mission adopts a two-rendezvous-one-impact approach. The first rendezvous is used to conduct high-speed impact flight drills, assess impact accuracy in orbit, and adjust guidance and control parameters to ensure a successful impact on the target during the second rendezvous.

[0072] A range sensor is installed on the impactor to measure the relative distance to the asteroid and to invert the lateral accuracy when passing through the virtual impact point.

[0073] An optical navigation sensor is installed on the impactor. The navigation sensor is calibrated before the biased impact. Based on the asteroid's optical image, the longitudinal accuracy when passing through the virtual impact point is inverted.

[0074] Based on multiple distance measurements from the distance sensor before and after the rendezvous point , Let n be the total number of intersections, and satisfy the following theoretical function: ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function: ;in, This refers to the collision time between the impactors; This is the collision distance between the impactors;

[0075] Based on this, the closest encounter distance of the impactor can be estimated. Therefore, the lateral impact accuracy is: ,in, This represents the lateral distance from the theoretical aiming point.

[0076] Based on multiple imaging data from the optical navigation sensor before and after rendezvous, the centroid position of the asteroid image was calculated using the gray-scale centroid method. The expression is:

[0077] ,

[0078] In the formula: represents the brightness value of the corresponding pixel; m and n are the number of pixels in the navigation sensor; ;

[0079] The imaging data of all navigation sensors were collected within the time period. The position of the asteroid centroid in the image was extracted. The long-period variation law of the asteroid centroid in the image was fitted to obtain the long-period variation law between the navigation sensor and the star sensor.

[0080] The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is:

[0081]

[0082] In the formula: Focal length of the navigation sensor; This represents the components of the relative position vector in the camera imaging coordinate system.

[0083] Overall bias impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is:

[0084] .

[0085] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0086] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for evaluating the accuracy of asteroid offset impacts, characterized in that, include: Step 1: Utilize the opportunity of the first encounter in an asteroid impact mission to conduct an offset impact; Step 2: Evaluate the lateral impact accuracy using the range sensor on the impactor; Step 3: Evaluate the longitudinal impact accuracy using optical image inversion via the optical navigation sensor on the impactor; Step 4: Evaluate the offset impact accuracy based on both lateral and longitudinal impact accuracy. Based on multiple distance measurements from the distance sensor before and after the rendezvous point , Let n be the total number of intersections, and satisfy the following theoretical function: ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function: ;in, This refers to the collision time between the impactors; This is the collision distance between the impactors; Based on this, the closest encounter distance of the impactor can be estimated. Therefore, the lateral impact accuracy is: ,in, The lateral distance from the theoretical aiming point; Based on multiple imaging data from the optical navigation sensor before and after rendezvous, the centroid position of the asteroid image was calculated using the gray-scale centroid method. The expression is: ， In the formula: represents the brightness value of the corresponding pixel; m and n are the number of pixels in the navigation sensor; ; The imaging data of all navigation sensors were collected within the time period. The position of the asteroid centroid in the image was extracted. The long-period variation law of the asteroid centroid in the image was fitted to obtain the long-period variation law between the navigation sensor and the star sensor. The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is: In the formula: Focal length of the navigation sensor; This represents the components of the relative position vector in the camera imaging coordinate system.

2. The asteroid offset impact accuracy assessment method according to claim 1, characterized in that, The asteroid impact mission adopts a two-rendezvous-one-impact approach. The first rendezvous is used to conduct high-speed impact flight drills, assess impact accuracy in orbit, and adjust guidance and control parameters to ensure a successful impact on the target during the second rendezvous. A range sensor is installed on the impactor to measure the relative distance to the asteroid and to invert the lateral accuracy when passing through the virtual impact point. An optical navigation sensor is installed on the impactor. The navigation sensor is calibrated before the biased impact. Based on the asteroid's optical image, the longitudinal accuracy when passing through the virtual impact point is inverted.

3. The asteroid offset impact accuracy assessment method according to claim 1, characterized in that, Overall bias impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is: 。 4. A system for assessing the accuracy of asteroid offset impacts, characterized in that, include: Module M1: To conduct an offset impact during the first rendezvous in an asteroid impact mission; Module M2: Evaluates lateral impact accuracy using a range sensor on the impactor; Module M3: Uses optical image inversion to evaluate longitudinal impact accuracy via an optical navigation sensor on the impactor; Module M4: Evaluates offset impact accuracy based on both lateral and longitudinal impact accuracy. Based on multiple distance measurements from the distance sensor before and after the rendezvous point , Let n be the total number of intersections, and satisfy the following theoretical function: ,in For the parameters to be determined, the least squares fitting method is used to optimize the objective function: ;in, This refers to the collision time between the impactors; This is the collision distance between the impactors; Based on this, the closest encounter distance of the impactor can be estimated. Therefore, the lateral impact accuracy is: ,in, The lateral distance from the theoretical aiming point; Based on multiple imaging data from the optical navigation sensor before and after rendezvous, the centroid position of the asteroid image was calculated using the gray-scale centroid method. The expression is: ， In the formula: represents the brightness value of the corresponding pixel; m and n are the number of pixels in the navigation sensor; ; The imaging data of all navigation sensors were collected within the time period. The position of the asteroid centroid in the image was extracted. The long-period variation law of the asteroid centroid in the image was fitted to obtain the long-period variation law between the navigation sensor and the star sensor. The position of the asteroid's centroid in the image is corrected based on the changing pattern to eliminate the long-period motion of the asteroid's centroid across multiple frames. The deviation between the fitted position and the theoretical position on the two-dimensional focal plane of the navigation sensor is also considered. The longitudinal deviation is calculated in reverse, and the expression is: In the formula: Focal length of the navigation sensor; This represents the components of the relative position vector in the camera imaging coordinate system.

5. The asteroid offset impact accuracy assessment system according to claim 4, characterized in that, The asteroid impact mission adopts a two-rendezvous-one-impact approach. The first rendezvous is used to conduct high-speed impact flight drills, assess impact accuracy in orbit, and adjust guidance and control parameters to ensure a successful impact on the target during the second rendezvous. A range sensor is installed on the impactor to measure the relative distance to the asteroid and to invert the lateral accuracy when passing through the virtual impact point. An optical navigation sensor is installed on the impactor. The navigation sensor is calibrated before the biased impact. Based on the asteroid's optical image, the longitudinal accuracy when passing through the virtual impact point is inverted.

6. The asteroid offset impact accuracy assessment system according to claim 4, characterized in that, Overall bias impact accuracy Based on lateral impact accuracy and longitudinal impact accuracy The expression is: 。

Images