Spacecraft return capsule positioning method and apparatus, terminal, storage medium and program product

Abstract

The application relates to the field of spaceflight measurement and control technology and provides a spaceship return capsule positioning method, a device, a terminal, a storage medium and a computer program product, the method comprising the following steps: marking all the stations in more than three stations as first effective stations; acquiring angle measurement data of each station in the first effective stations to obtain the angle measurement data of the first effective stations; performing two-station non-plane intersection according to the angle measurement data of each two stations in the first effective stations to obtain a first intersection point set; screening out outlier intersection points in the first intersection point set by adopting a sliding window least square operator to obtain a first continuous intersection result; determining the effectiveness of the angle measurement data of each station according to the first continuous intersection result and the angle measurement data of each station to determine second effective stations. The scheme generates an intersection point set based on a two-station non-plane intersection positioning method, uses an adaptive space screening method and a target vector included angle threshold judgment method to determine the effectiveness of each station, and improves the measurement precision.

Description

Technical Field

[0001] This invention relates to the field of aerospace telemetry and control technology, specifically to a spacecraft return capsule positioning method, device, terminal, storage medium, and computer program product, and particularly to a highly robust spacecraft return capsule multi-station optical rendezvous positioning method, device, terminal, storage medium, and computer program product. Background Technology

[0002] Real-time position information of the return capsule during the manned spacecraft's recovery and landing phase is crucial data for space search and rescue operations. After the spacecraft's main parachute deploys, because the return capsule's altitude is below the lower limit of the angular measurement range of the measuring equipment outside the landing site, its real-time positioning relies on the rendezvous and measurement of multiple small landing point imaging devices within the landing site. However, this positioning measurement task faces numerous difficulties that affect measurement accuracy.

[0003] Therefore, there is an urgent need to develop a method, device, terminal, storage medium, and computer program product for positioning spacecraft return capsules. In particular, there is a highly robust method, device, terminal, storage medium, and computer program product for optical rendezvous positioning of spacecraft return capsules at multiple stations. This product should be able to generate a set of rendezvous points based on a two-station non-plane rendezvous positioning method, and automatically determine the validity of the angle measurement data of each station by using an adaptive spatial filtering method based on a sliding window least squares operator and a target vector angle threshold judgment method. This would improve the accuracy of rendezvous positioning measurements and solve the problem of low accuracy in real-time positioning information measurement of return capsules during the recovery and landing phase of manned spacecraft.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a spacecraft return capsule positioning method, device, terminal, storage medium, and computer program product.

[0006] To address the aforementioned technical problems, as one aspect of the present invention, a method for locating a spacecraft return capsule is provided, applied to optical rendezvous and positioning of a spacecraft return capsule using three or more measuring stations. The method includes the following steps: marking all measuring stations among the three or more measuring stations as valid measuring stations, denoted as the first valid measuring station; acquiring the angular measurement data of each measuring station within the first valid measuring station, thereby obtaining the angular measurement data of the first valid measuring station; and performing a two-station skew-plane intersection based on the angular measurement data of every two measuring stations within the first valid measuring station, thereby obtaining the intersection point set of the first valid measuring station, denoted as the first... A set of intersection points is generated. For the first set of intersection points, a sliding window least squares operator is used to generate an adaptive spatial filtering region, which automatically filters out outlier intersection points in the first set of intersection points. After denoising and smoothing, continuous intersection results of the first effective station are obtained, resulting in the first continuous intersection result. Based on the first continuous intersection result and the angle measurement data of each station in the first effective station, the validity of the angle measurement data of each station in the first effective station is determined to identify a new effective station in the first effective station, which is denoted as the second effective station. This initially realizes the positioning of the spacecraft return capsule and the positioning of all effective stations among three or more stations.

[0007] According to an exemplary embodiment of the present invention, the method further includes: after determining a new effective station among the first effective stations, denoted as the second effective station, re-acquiring the angle measurement data of each station among the first effective stations, thereby obtaining the angle measurement data of the first effective station again; for the second effective station and the re-acquired angle measurement data of the first effective station, performing two-station skew intersection based on the angle measurement data of every two stations among the second effective stations, thereby obtaining the intersection point set of the second effective station, denoted as the second intersection point set; and for the second intersection point set, using a sliding window least squares operator to generate an adaptive spatial filtering region. Outlier intersection points in the second intersection point set are automatically filtered out, and after denoising and smoothing, continuous intersection results of the second effective stations are obtained, resulting in the second continuous intersection result. Based on the second continuous intersection result and the angle measurement data of each station in the first effective stations, the validity of the angle measurement data of each station in the first effective stations is determined, so as to redetermine new effective stations in the first effective stations, which are recorded as the third effective stations, to further realize the positioning of the spacecraft return capsule and the positioning of all effective stations among three or more stations. This process is repeated to realize the positioning of the spacecraft return capsule and the positioning of all effective stations among three or more stations.

[0008] According to an exemplary embodiment of the present invention, for a first effective station, a two-station non-planar intersection is performed based on the angle measurement data of every two stations in the first effective station, thereby obtaining a set of intersection points for the first effective station, denoted as the first intersection point set. This includes: for the first effective station, using a two-station non-planar intersection method, taking the angle measurement data of every two stations in the first effective station as one frame of data, and performing a two-station non-planar intersection for every two stations to obtain... There are three intersection points P, where N represents the number of first valid stations and N is a positive integer.

[0009] According to an exemplary embodiment of the present invention, for the first intersection point set, an adaptive spatial filtering region is generated using a sliding window least squares operator to automatically filter out outlier intersection points in the first intersection point set. After denoising and smoothing, continuous intersection results of the first effective stations are obtained, resulting in the first continuous intersection result. This includes: using a sliding window least squares operator to fit the curve of the relative time of intersection points in the first continuous intersection result to obtain the center and radius parameters of the sphere, generating a spherical spatial filtering region; based on the spherical spatial filtering region, outlier intersection points are filtered out from the first intersection point set to obtain a subset of the symbol target range, denoted as the reasonable subset; the average value of the reasonable subset is calculated to update the least squares operator, and the fitting points of the curve of the relative time of intersection points in the first continuous intersection result are recalculated as the multi-station intersection result of the current frame, thus obtaining the first continuous intersection result.

[0010] According to an exemplary embodiment of the present invention, a sliding window least squares operator is used to fit the curve of the relative time of the intersection points in the first continuous intersection results to obtain the center and radius parameters of the sphere and generate a spherical spatial screening area. This includes: using the sliding window least squares operator LS(P,t), with the intersection points in the first continuous intersection results as sample data, the window data capacity as a constant K, and the data inflow / outflow method as data first-in-first-out, fitting the curve F(t) of the relative time of the intersection points in the first continuous intersection results within a preset window time period, and calculating the curve derivative v = F′(t); for the k-th frame of data, using the fitting points of the curve F(t)... Construct a spherical spatial screening region with center R = D·v·Δt.

[0011] According to an exemplary embodiment of the present invention, based on the first continuous intersection result and the angle measurement data of each station in the first effective stations, the validity of the angle measurement data of each station in the first effective stations is determined to identify new effective stations in the first effective stations, denoted as second effective stations. This includes: calculating the vector of the first continuous intersection result relative to each station in the first effective stations, and calculating the angle between the vector and the actual angle measurement vector corresponding to the angle measurement data of each station in the first effective stations; determining whether the angle corresponding to any station in the first effective stations is less than a preset angle threshold: if so, the angle measurement data of that station is determined to be valid, and it is designated as a new effective station in the first effective stations, and all new effective stations in the first effective stations are denoted as second effective stations; otherwise, the angle measurement data of that station is determined to be invalid, and that station is not added to the second effective stations.

[0012] As a second aspect of the present invention, the present invention provides a spacecraft return capsule positioning device, applied to optical rendezvous positioning of three or more stations on a spacecraft return capsule; the spacecraft return capsule positioning device includes: a control unit configured to mark all stations among the three or more stations as valid stations, denoted as the first valid stations; an acquisition unit configured to acquire angular measurement data of each station among the first valid stations, thereby obtaining angular measurement data of the first valid station; the control unit is further configured to perform two-station non-planar rendezvous based on the angular measurement data of every two stations among the first valid stations, thereby obtaining a set of rendezvous points of the first valid station, denoted as the first rendezvous. The control unit is further configured to, for the first intersection point set, use a sliding window least squares operator to generate an adaptive spatial filtering region, automatically filter out outlier intersection points in the first intersection point set, and perform denoising and smoothing processing to obtain the continuous intersection results of the first effective station, thus obtaining the first continuous intersection result; the control unit is further configured to, based on the first continuous intersection result and the angle measurement data of each station in the first effective station, determine the validity of the angle measurement data of each station in the first effective station, so as to determine a new effective station in the first effective station, denoted as the second effective station, thus initially realizing the positioning of the spacecraft return capsule and the positioning of the effective stations among all three or more stations.

[0013] As a third aspect of the present invention, the present invention provides a terminal, including: the spacecraft return capsule positioning device described above.

[0014] As a fourth aspect of the present invention, the present invention provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the spacecraft return capsule positioning method described above.

[0015] As a fifth aspect of the present invention, the present invention provides a computer program that, when executed by a processor, implements the steps of the spacecraft return capsule positioning method described above.

[0016] The beneficial effects of this invention are:

[0017] The method of this invention generates a set of intersection points based on a two-station non-planar intersection positioning method for multiple stations on the spacecraft's return capsule. It then automatically determines the validity of the angle measurement data from each station using an adaptive spatial filtering method based on a sliding window least squares operator and a target vector angle threshold judgment method. This improves the measurement accuracy of the return capsule's real-time position information during the manned spacecraft's recovery and landing phase, solving the problem of low measurement accuracy of the return capsule's real-time position information during the manned spacecraft's recovery and landing phase. In other words, it improves the accuracy of intersection positioning measurements, addressing the issue of low measurement accuracy of the return capsule's real-time position information during the manned spacecraft's recovery and landing phase. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of the spacecraft return capsule positioning method of the present invention;

[0019] Figure 2 This is a flowchart illustrating an embodiment of the method for cyclically determining valid stations in the present invention;

[0020] Figure 3 This is a flowchart illustrating an embodiment of the method of the present invention for determining a first consecutive intersection result for the first intersection point set;

[0021] Figure 4 This is a flowchart illustrating an embodiment of the method for generating a spherical spatial screening region in the present invention.

[0022] Figure 5 This is a flowchart illustrating an embodiment of the method of the present invention for determining a second effective station among all three or more stations (i.e., the first effective stations);

[0023] Figure 6 This is a schematic diagram of a structure of an embodiment of the spacecraft return capsule positioning device of the present invention;

[0024] Figure 7 This is a coordinate diagram showing the intersection of two stations with different planes among the multiple tracking stations on the spacecraft's return capsule;

[0025] Figure 8 This is a flowchart illustrating the highly robust optical rendezvous and positioning method for multiple stations of a spacecraft return capsule according to the present invention.

[0026] Figure 9This is a schematic diagram of the software interface for the highly robust optical rendezvous and positioning method for multiple stations of the spacecraft return capsule, which is based on the present invention.

[0027] Wherein, 100 is the acquisition unit and 200 is the control unit. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0029] This invention relates to the field of aerospace telemetry and control, particularly to the field of optical external measurement and positioning of manned spacecraft return capsules. It addresses the issue of low measurement accuracy of the return capsule's real-time position information during the manned spacecraft's recovery and landing phase. For example:

[0030] (1) The landing area is more than 1,000 square kilometers. In order to meet the requirements of scene coverage, the landing scene equipment is scattered. The distance between the target and the station and the intersection baseline of the station are both in the range of 10 to 20 kilometers. Factors such as atmospheric refraction, atmospheric disturbance and Earth curvature will lead to target angle measurement error and intersection calculation error.

[0031] (2) Due to the miniaturization requirements, the angle measurement accuracy of the landing point imaging equipment is relatively low;

[0032] (3) The landing point image equipment does not have target detection and tracking functions and miss distance information, which leads to an uncertain deviation between the equipment's angle measurement data and the return capsule's actual azimuth and pitch values ​​relative to the equipment within a half field of view.

[0033] (4) Due to the limitations of the landing site's mobile deployment conditions, the orientation and leveling errors of the landing site's visual equipment are relatively large;

[0034] (5) The deployment and takeoff of components such as the guide parachute, deceleration parachute, main parachute, and heat shield of the return capsule affect the tracking stability of the equipment operator, resulting in deviations and fluctuations in the angle measurement data;

[0035] (6) According to the mission flow, some equipment switched from tracking the main target of the return capsule to tracking secondary targets such as the flying-off components. After the tracking was completed, it switched back to tracking the main target. This puts extremely high demands on the adaptability of the rendezvous and positioning method.

[0036] Multiple factors make real-time positioning of the return capsule during the spacecraft's recovery and landing phase extremely difficult, and the relevant solutions are insufficient to meet the intersection calculation requirements of more than 10 landing point imaging devices under the aforementioned conditions.

[0037] For example, the least squares method proposed by Yan Shoufeng[1] and the multi-faceted least squares method proposed by Wu Nengwei[2] are estimations between multiple two-station intersection points, not fitting of the relative time change of the comprehensive result of multi-station positioning points. The method does not consider the information of the relative time change of intersection points.

[0038] Zhang Lingxia[3] adopted the method of calculating the inverse variance of each pair of intersection results and weighted summation to integrate multiple intersection results. This method has good adaptability to the angle measurement data error of the equipment. However, when the angle measurement data error of the equipment is generally large, the effect is close to taking the average directly. It is also not suitable for the situation where some landing point scene equipment turns to secondary targets during the recovery and landing phase of the manned spacecraft.

[0039] The method of cross-section measurement proposed by Hou Honglu [4] is consistent with the two-station cross-section method used in this invention, but it does not provide a method for dealing with various angle measurement error interferences.

[0040] Yu Guodong [5] adopted a robust estimation method to deal with the interference of angle measurement data deviation and outlier values ​​on the intersection results. The method is to improve the intersection accuracy by continuously adjusting the observation value weight matrix. Similar to article [1], it does not consider the change information of the intersection point relative to time, and is not suitable for the continuous change of the target position.

[0041] Liang Jiahui [6] proposed a fusion fault-tolerant positioning method based on minimum distance sum. This method is comprehensive and highly feasible. However, the fusion positioning process for the target position cannot adapt to the change in the number of stations. Its adaptive fault-tolerant algorithm uses azimuth and elevation angle as the criterion for outlier removal, which will lead to misjudgment due to the large azimuth angle caused by secant compensation at high elevation angle.

[0042] The above-mentioned solutions are from:

[0043] [1] Yan Shoufeng, Lü Fenghai, Liu Zhongkan. Algorithm for intersection measurement of cinema theodolite based on least squares estimation [J]. Journal of Beijing University of Aeronautics and Astronautics, 1998, No. 5, 588-592.

[0044] [2] Wu Nengwei, Chen Tao. Multi-station intersection method based on least squares estimation [J]. Opto-Electronic Engineering, 2008, 35(12):1-4.

[0045] [3] Zhang Lingxia, Ma Caiwen, Chen Ming, Cao Xiaoqing. A method for processing data of multiple intersection measurements of photoelectric theodolites at a target range [J]. Acta Geodaetica et Cartographica Sinica, 2003, Vol. 2, 139-142.

[0046] [4] Hou Honglu, Zhou Deyun. Optical intersection measurement and network layout optimization design of photoelectric theodolite[J]. Acta Photonica Sinica, 2008, 37(5):1023-1028.

[0047] [5] Yu Guodong, Wang Chunyang. Robust estimation algorithm for multi-station intersection of optical theodolites [J]. Liquid Crystals and Displays, 2018, Vol. 33, No. 4, 299-305.

[0048] [6] Liang Jiahui, Li Jian, Hu Shaolin. Fault-tolerant minimum distance sum of squares positioning based on joint tracking of multiple optical theodolites [J]. Optics and Precision Engineering, 2020, 28, No. 12, 2596-2604.

[0049] Therefore, the present invention proposes a spacecraft reentry capsule positioning method, device, terminal, storage medium, and computer program product. Specifically, it is a highly robust optical rendezvous positioning method, device, terminal, storage medium, and computer program product for multiple stations of a spacecraft reentry capsule. When determining the real-time position of the reentry capsule during the manned spacecraft recovery and landing phase, it generates a set of rendezvous points based on a two-station non-plane rendezvous positioning method. It achieves high robustness by utilizing an adaptive spatial filtering method based on a sliding window least squares operator and a target vector angle threshold judgment method, thereby improving the measurement accuracy of the real-time position information of the reentry capsule during the manned spacecraft recovery and landing phase.

[0050] As a first embodiment of the present invention, a method for locating a spacecraft return capsule is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. This spacecraft return capsule positioning method is applied to optical rendezvous positioning of the spacecraft return capsule at three or more tracking stations; the spacecraft return capsule positioning method includes steps S110 to S150.

[0051] In step S110, all stations out of the three or more stations are marked as valid stations, and are referred to as the first valid station.

[0052] In step S120, for the first effective station, the angle measurement data of each station in the first effective station is obtained, thereby obtaining the angle measurement data of the first effective station.

[0053] In step S130, for the first effective station, based on the angle measurement data of every two stations in the first effective station, a two-station skew intersection is performed to obtain the intersection point set of the first effective station, denoted as the first intersection point set, such as the intersection point set {P}.

[0054] In step S140, for the first intersection point set, an adaptive spatial filtering region is generated using a sliding window least squares operator to automatically filter out outlier intersection points in the first intersection point set. After denoising and smoothing, the continuous intersection results of the first effective station are obtained, thus obtaining the first continuous intersection result.

[0055] In step S150, based on the first continuous rendezvous results and the angle measurement data of each station in the first effective station, the validity of the angle measurement data of each station in the first effective station is determined, so as to identify a new effective station in the first effective station, which is recorded as the second effective station, thus initially realizing the positioning of the spacecraft return capsule and the positioning of the effective stations among all three or more stations.

[0056] This invention provides a robust optical rendezvous and positioning method for a spacecraft reentry capsule using multiple stations. This method is used to determine the real-time position of the reentry capsule during the manned spacecraft recovery and landing phase, solving the difficulties in rendezvous and positioning caused by factors such as large angular measurement errors of landing site imaging equipment, some equipment tracking secondary targets, and various limiting conditions within the landing site. The method generates a set of rendezvous points based on a two-station non-plane rendezvous and positioning method. It then utilizes an adaptive spatial filtering method based on a sliding window least squares operator and a target vector angle threshold judgment method to achieve robust real-time target fusion positioning, improving the measurement accuracy of the reentry capsule's real-time position information during the manned spacecraft recovery and landing phase.

[0057] In some embodiments, the spacecraft return capsule positioning method of the present invention further includes: a process of cyclically determining valid tracking stations.

[0058] The following is combined Figure 2 The flowchart of an embodiment of the method of the present invention for cyclically determining valid stations is shown below. The specific process of cyclically determining valid stations is further explained, including steps S210 to S250.

[0059] Step S210: After determining the new effective station in the first effective station and recording it as the second effective station, re-acquire the angle measurement data of each station in the first effective station for the first effective station, thereby obtaining the angle measurement data of the first effective station again.

[0060] Step S220: For the angle measurement data of the second effective station and the re-obtained first effective station, perform two-station skew intersection based on the angle measurement data of every two stations in the second effective station, thereby obtaining the intersection point set of the second effective station, denoted as the second intersection point set.

[0061] Step S230: For the second intersection point set, the sliding window least squares operator is used to generate an adaptive spatial filtering region, automatically filtering out outlier intersection points in the second intersection point set, and after denoising and smoothing, the continuous intersection results of the second effective station are obtained, thus obtaining the second continuous intersection results.

[0062] Step S240: Based on the second continuous rendezvous result and the angle measurement data of each station in the first effective station, determine the validity of the angle measurement data of each station in the first effective station, so as to re-determine a new effective station in the first effective station, which is recorded as the third effective station, and further realize the positioning of the spacecraft return capsule and the positioning of the effective stations among all three or more stations.

[0063] Step S250 is repeated in this way to achieve the positioning of the spacecraft return capsule and the positioning of the valid stations among all three or more stations.

[0064] In other words, because valid and invalid stations can transform into each other due to changes in the actual situation, each cycle involves acquiring angle measurement data from all stations (i.e., the first valid stations) out of the three or more stations, and combining this with the current continuous intersection results and the angle measurement data from each station (i.e., the first valid stations) to determine the next round of valid stations from all stations (i.e., the first valid stations) out of the three or more stations.

[0065] The solution of this invention can solve the problem of positioning the return capsule due to various conditions in the landing site, even when the angle measurement error of the imaging equipment at each landing point is large and some equipment switches to tracking secondary targets at irregular intervals. It can achieve real-time positioning of the return capsule during the recovery and landing phase of the manned spacecraft, and the positioning accuracy can meet the needs of aerospace search and rescue work. It also has broad application prospects in other spacecraft return and landing scenarios.

[0066] In some implementations, step S130 involves performing a two-station non-planar intersection based on the angular measurement data of every two stations in the first effective station, thereby obtaining a set of intersection points for the first effective station, denoted as the first intersection point set. This includes: for the first effective station, using a two-station non-planar intersection method, taking the angular measurement data of every two stations in the first effective station as one frame of data, and performing a two-station non-planar intersection for every two stations to obtain... There are three intersection points P, where N represents the number of first valid stations and N is a positive integer.

[0067] Figure 7 This is a coordinate diagram showing the intersection of two stations with different planes among the multiple tracking stations on the spacecraft's return capsule. For example... Figure 7As shown, given the station locations O1(x1,y1,z1) and O2(x2,y2,z2) in the Earth-centered Earth-fixed coordinate system, and considering that both stations simultaneously measure the azimuth and elevation angles (a1,e1) and (a2,e2) of the target in their respective station coordinate systems, and considering the two angular straight lines L1 and L2 from the stations to the return capsule, the theoretical position of the return capsule should be the intersection of the spatial lines L1 and L2. However, in practice, due to various systematic and random errors, lines L1 and L2 usually do not intersect at a single point. Therefore, the common perpendicular segment of lines L1 and L2 is used instead. If the midpoint P is taken as the position of the return capsule, then the calculation steps for the optical intersection point P of the two stations are as follows:

[0068] Step S11: Add any non-zero radius r to the two angle measurement data as auxiliary points, namely auxiliary points (r,a1,e1) and (r,a2,e2), and convert them into points (x1′,y1′,z1′) and (x2′,y2′,z2′) in the geocentric geofixed coordinate system. The conversion calculation process can refer to the relevant conversion calculation process in this field.

[0069] Step S12: Calculate the vector using auxiliary points and station locations. and vector The formula is:

[0070]

[0071] Step S13: Calculate the common perpendicular segment vector

[0072] Step S14: Solve the following equation to obtain the common perpendicular segment. The foot of the perpendicular M(x) M ,y M ,z M ) and the foot of the perpendicular N(x) N ,y N ,z N ):

[0073]

[0074] Step S15: Find the midpoints of points M and N, i.e., the intersection points.

[0075] Figure 8 This is a flowchart illustrating the highly robust optical rendezvous and positioning method for a spacecraft return capsule using multiple stations, as proposed in this invention. The method mainly includes two-station non-planar rendezvous, sliding window least squares (LS) operator, adaptive spherical space filtering of outlier rendezvous points, and target vector angle threshold judgment. The positioning process is as follows: Figure 8As shown. Figure 8 As shown, the present invention proposes a highly robust optical rendezvous and positioning method for multiple stations on a spacecraft return capsule, the specific steps of which include:

[0076] Step S21: Use the two-station non-plane intersection method to traverse and calculate the angle measurement data of the current frame to obtain the intersection point set {P}. For example: Use the two-station non-plane intersection method to traverse and calculate the effective station angle measurement data of the k-th frame to obtain the intersection point set {P}.

[0077] Specifically, the two-station non-planar intersection method is used to traverse and calculate the effective station angle measurement data of the k-th frame, obtaining the intersection point set {P}, including: initializing and marking all N stations as effective stations, acquiring the angle measurement data of all stations to the target as 1 frame of data, and performing two-station non-planar intersection for every two stations to obtain... There are several intersection points P, where N is a positive integer. Then, proceed to step 22.

[0078] Here, "every two stations" refers to every two stations out of all N valid stations. The method for obtaining the number of intersection points is a combination formula. In addition, the total number of all stations is N. At the beginning of the algorithm, all stations are marked as valid stations. Therefore, the number of first valid stations is also N. That is, for all stations (i.e., the first valid stations) among two or more stations, the second valid stations, the third valid stations, etc. are determined.

[0079] The present invention proposes a highly robust optical rendezvous and positioning scheme for multiple stations on a spacecraft reentry capsule. This scheme utilizes a two-station, non-planar rendezvous and positioning method to traverse effective angle measurement data to form a set of rendezvous points. It then uses a sliding window least squares operator based on multiple frames of rendezvous results to generate an adaptive spatial filtering region, automatically removing outlier rendezvous points and generating denoised and smoothed continuous rendezvous results. Finally, it uses an angle threshold between the rendezvous result vector and the actual angle measurement vector to automatically determine the validity of the angle measurement data from each station, achieving highly robust real-time target fusion positioning and improving the measurement accuracy of the reentry capsule's real-time position information during the manned spacecraft's recovery and landing phase.

[0080] In some implementations, in step S140, for the first intersection point set, a sliding window least squares operator is used to generate an adaptive spatial filtering region, automatically filtering out outlier intersection points in the first intersection point set, and after denoising and smoothing, the continuous intersection results of the first effective station are obtained. For the specific process of obtaining the first continuous intersection results, please refer to the following exemplary description.

[0081] The following is combined Figure 3The flowchart shown is an embodiment of the method of the present invention for determining the first continuous intersection result for the first intersection point set. The specific process of determining the first continuous intersection result for the first intersection point set in step S140 is further explained, including steps S310 to S330.

[0082] Step S310: Using the least squares operator of the sliding window, fit the curve of the intersection point relative to time in the first continuous intersection result to obtain the center and radius parameters of the sphere and generate the spherical space screening area.

[0083] Step S320: Based on the spherical space screening area, outlier intersection points are screened out from the first intersection point set to obtain a subset of the symbol target range, denoted as the reasonable subset.

[0084] Step S330: Calculate the average value of the reasonable subset to update the least squares operator, recalculate the fitting point of the curve of the intersection point relative to time in the first continuous intersection result, and use it as the multi-station intersection result of the current frame to obtain the first continuous intersection result.

[0085] like Figure 8 As shown, the present invention proposes a highly robust optical rendezvous and positioning method for multiple stations on a spacecraft return capsule, the specific steps of which include:

[0086] Step S22: Fit the curve of the intersection point relative to time using the sliding window least squares operator to obtain the center and radius parameters of the sphere, generate a spherical space screening area, filter out outlier intersection points from the point set {P} to obtain a reasonable subset, calculate the average value of the subset to update the least squares operator, and recalculate the curve fitting points as the multi-station intersection results of the current frame.

[0087] In the solution of this invention, the curve of multi-station intersection positioning results versus time is fitted by the least squares operator, outlier intersection points caused by large angle measurement deviations are automatically screened out by the adaptive spherical screening algorithm, and stations tracking secondary targets are automatically excluded and included by the angle threshold between the target vector and the actual angle measurement vector. The process is clear and the required functions can be implemented through program design.

[0088] In some implementations, step S310 uses a sliding window least squares operator to fit the curve of the intersection point relative to time in the first continuous intersection result to obtain the center and radius parameters of the sphere, and the specific process of generating the spherical spatial screening area is described in the following exemplary description.

[0089] The following is combined Figure 4 The schematic diagram shown is a flowchart of an embodiment of the method of the present invention for generating a spherical spatial screening area. It further illustrates the specific process of generating the spherical spatial screening area in step S310, including steps S410 to S420.

[0090] Step S410: Using the least squares operator LS(P,t) of the sliding window, with the intersection points in the first continuous intersection results as sample data, the window data capacity as a constant K, and the data entry and exit method as data first-in-first-out, the curve F(t) of the intersection points relative to the time in the first continuous intersection results within the preset window time period is fitted, and the curve derivative v = F′(t) is calculated.

[0091] Step S420: For the k-th frame of data, use the fitting points of the curve F(t) Construct a spherical spatial screening region with center R = D·v·Δt.

[0092] Specifically, in step 22, the method of using the sliding window least squares operator to filter intersection points and obtain multi-station intersection results includes the following specific steps:

[0093] Step S221: Using the sliding window least squares operator LS(P,t), the sample data type is the intersection point P, the window data capacity is a constant K, and the data is first-in-first-out, the curve F(t) of the intersection point relative to the time within the window time period is fitted, and the curve derivative v=F′(t) is calculated.

[0094] In step S221, a sliding window least squares operator LS(P,t) is designed. The sample data type is the intersection point P, the window data capacity is a constant K, and the data is first-in-first-out. The operator can fit the curve F(t) of the intersection point relative to time within the window time period to smooth the intersection result. The curve derivative v=F′(t) is the target flight speed used to calculate the radius of the spherical screening area.

[0095] Step S222: For the k-th frame of data, use the curve fitting points... Construct a spherical spatial screening region with center R = D·v·Δt.

[0096] In step S222, the average value of the intersection point set {P} of one frame of data is calculated and used as the sample data for the operator LS(P,t). K frames of data are continuously calculated to make the operator have the fitting conditions and serve as the starting state of the loop process. The K in "continuously calculate K frames of data" is consistent with "the window data capacity is a constant K".

[0097] Then, new k-th frame data is obtained, and the operator is used to fit the points. A spherical spatial screening region is drawn with R = D·v·Δt as the center. Where Δt is the data frame interval time, and D is a constant.

[0098] Step S223: Select a subset from the point set {P} And calculate its average value.

[0099] Specifically, calculate the set of intersection points {P} of all valid stations in the k-th frame of data, and filter out those points that fall within the intersection points. A subset within, i.e. And calculate its average value.

[0100] In the scheme of this invention, the method of taking effective stations, performing intersections between two stations, and then averaging the results ensures the algorithm's universality for different numbers of stations and its adaptability to real-time changes in the number of effective stations. The purpose of the screening process is to eliminate outlier intersection points caused by large angle measurement errors.

[0101] Step S224: Use the average value Update the least squares operator LS(P,t) curve and recalculate the fitted points. This serves as the result of multi-station intersection of the data in the k-th frame.

[0102] Specifically, using subset average Update the sample data for the least squares operator LS(P,t) and recalculate the operator fit points. This serves as the result of multi-station intersection of the data in the k-th frame.

[0103] In the solution of this invention, a threshold angle ∠Th is set; if ∠U i >∠Th, then station O i The angle measurement data is invalid and is marked as an invalid station. If ∠U i If the value is less than 0.9·∠Th, then mark station O. i For a valid station, if there are fewer than 3 valid stations, then ∠U i Sort by size from smallest to largest, and then sort by ∠U i The three smallest number of devices are marked as valid stations; proceed to step S222 for iterative calculation. "Valid stations" and "invalid stations" refer to whether the station's angle measurement data effectively tracks the main target. In this invention, limiting the minimum number of valid stations ensures sufficient valid intersection points in step S223, preventing the iterative calculation from failing.

[0104] In some implementations, the specific process of determining the validity of the angle measurement data of each station in the first effective station based on the first continuous intersection result and the angle measurement data of each station in the first effective station in step S150, so as to determine a new effective station in the first effective station, denoted as the second effective station, is described in the following exemplary description.

[0105] The following is combined Figure 5Schematic diagram of an embodiment for determining the second valid station for all stations (i.e., the first valid stations) among more than three stations in the method of the present invention, further illustrating the specific process of determining the second valid station for all stations (i.e., the first valid stations) among more than three stations in step S150, including: steps S510 to S520.

[0106] Step S510, calculate the vector of the first consecutive intersection result with respect to each station among the first valid stations, and calculate the included angle between this vector and the actual angle measurement vector corresponding to the angle measurement data of each station among the first valid stations.

[0107] Step S520, determine whether the included angle corresponding to any station among the first valid stations is less than a preset included angle threshold: if so, determine that the angle measurement data of this any station is valid, and use it as a new valid station among the first valid stations, and record all the new valid stations among the first valid stations as the second valid stations; otherwise, determine that the angle measurement data of this any station is invalid, and do not add this any station to the second valid stations. That is, for any station among all stations among more than three stations, determine whether the included angle between the vectors corresponding to this any station is less than a preset included angle threshold: if so, determine that the angle measurement data of this any station is valid, and use it as a new valid station among the first valid stations, and record all the new valid stations among the first valid stations as the second valid stations; otherwise, determine that the angle measurement data of this any station is invalid, and do not add this any station to the second valid stations.

[0108] As Figure 8 shown, a method for optical intersection positioning of multiple stations of a spacecraft return capsule with high robustness proposed by the solution of the present invention further includes the following specific steps:

[0109] Step S23, traverse all stations, calculate the vector of the multi-station intersection result with respect to the station, and the included angle between this vector and the actual angle measurement vector of each station. If this included angle is greater than a certain threshold, the angle measurement data of this station is marked as invalid and will not be used for the off-plane intersection in step 1 later; if this included angle is less than a certain threshold, it is marked as valid and will continue to be used for the off-plane intersection later.

[0110] Specifically, the method for judging the validity of angle measurement data by using the target vector included angle threshold includes the following specific steps:

[0111] Step S231, traverse station O i , 0 < i ≤ N, calculate the vector of the intersection result with respect to the station and calculate the included angle ∠U between and the actual angle measurement vector i .

[0112] Step S232: Set the included angle threshold ∠Th, if ∠U i >∠Th, then station O i The angle measurement data is invalid and is marked as an invalid station. If ∠U i If the value is less than 0.9·∠Th, then mark station O. i This establishes a valid measurement station; then, the next frame of data is looped. Based on actual usage, in step S222, constants K = 10 and D = 3 are used; in step S232, ∠Th = 1°. The value of ∠Th can be manually modified in real-time within the program.

[0113] In the scheme of this invention, the validity of station data is determined by using a target vector angle threshold. The purpose is to automatically exclude the angle measurement data of individual stations when they switch to tracking secondary targets, and automatically include the angle measurement data when they switch back to tracking primary targets. Setting 0.1·∠Th as a hysteresis buffer can prevent the validity of data from fluctuating around the threshold. The validity status of station data takes effect in step S223 when looping to the next frame of data. Using a vector angle threshold instead of the azimuth and elevation angle measurement deviation threshold of the station to the intersection result can avoid the waste of effective data due to false outliers in the azimuth angle caused by secant compensation when the target elevation angle is too high.

[0114] The software was developed using the Qt 5.12 / C++ environment. The software interface was designed, data transmission and display functions were developed, and the aforementioned multi-station intersection positioning method and steps were implemented. The software interface is shown below. Figure 9 As shown. Figure 9 This is a schematic diagram of the software interface for the highly robust optical rendezvous and positioning method for multiple stations of the spacecraft return capsule, which is based on the present invention.

[0115] The solution and software of this invention have been used multiple times in the real-time position measurement of the return capsule during the recovery and landing phase of the Shenzhou spacecraft. Using 10 landing point imaging devices, real-time positioning is achieved within a 1,000 square kilometer landing site, with a positioning error of no more than 50 meters, which can meet the needs of aerospace search and rescue work.

[0116] The present invention employs a two-station non-planar intersection method as the basic intersection method, which can adapt to intersection calculations under conditions of large station angular measurement errors. It uses a sliding window least squares operator to fit the intersection point trajectory curve within a window time period, which can filter data noise, smooth the intersection results, and serve as the parameter basis for the adaptive spherical space screening area. The spherical space screening of outlier intersection points can suppress the influence of large deviations in angular measurement data, improving the accuracy of the intersection positioning results. Using a vector threshold to determine the validity of angular measurement data can automatically exclude the angular measurement data of individual stations when they switch to tracking secondary targets, and automatically include the angular measurement data when they switch back to tracking the primary target. This reduces the influence of outlier data and allows for timely utilization of effective data. Compared with the azimuth and elevation angular measurement deviation threshold, it avoids wasting effective data due to false outliers in azimuth angle caused by secant compensation. The present invention can automatically adapt to changes in the number of stations, has a very wide tolerance for station angular measurement errors, and its positioning accuracy meets the requirements of aerospace search and rescue operations. It also has broad application prospects in other spacecraft return and landing scenarios.

[0117] The technical solution of this embodiment generates a set of intersection points based on the two-station non-plane intersection positioning method for multiple stations on the spacecraft return capsule. It then uses an adaptive spatial filtering method based on the sliding window least squares operator and a target vector angle threshold judgment method to automatically determine the validity of the angle measurement data of each station, thereby improving the accuracy of intersection positioning measurement and solving the problem of low accuracy of real-time positioning information measurement of the return capsule during the recovery and landing phase of the manned spacecraft.

[0118] According to a second embodiment of the present invention, a spacecraft return capsule positioning device corresponding to the spacecraft return capsule positioning method is also provided. See also Figure 6 The diagram shows a structural schematic of an embodiment of the device of the present invention. This spacecraft return capsule positioning device is used for optical rendezvous positioning of the spacecraft return capsule at three or more tracking stations; the spacecraft return capsule positioning device includes: an acquisition unit 100 and a control unit 200.

[0119] The control unit 200 is configured to mark all three or more stations as valid stations, designated as the first valid station. The specific functions and processing of this control unit 200 are described in step S110.

[0120] The acquisition unit 100 is configured to acquire angle measurement data of each station in the first effective station, thereby obtaining the angle measurement data of the first effective station. The specific functions and processing of the acquisition unit 100 are described in step S120.

[0121] The control unit 200 is further configured to perform eccentric intersection of two stations based on the angular measurement data of every two stations in the first effective station, thereby obtaining the intersection point set of the first effective station, denoted as the first intersection point set, such as intersection point set {P}. The specific functions and processing of this control unit 200 are further described in step S130.

[0122] The control unit 200 is further configured to use a sliding window least squares operator to generate an adaptive spatial filtering region for the first intersection point set, automatically filter out outlier intersection points in the first intersection point set, and perform denoising and smoothing processing to obtain the continuous intersection results of the first effective station, thus obtaining the first continuous intersection result. The specific functions and processing of this control unit 200 are further described in step S140.

[0123] The control unit 200 is further configured to determine the validity of the angle measurement data of each station in the first effective station based on the first continuous rendezvous result and the angle measurement data of each station in the first effective station, so as to identify a new effective station in the first effective station, which is denoted as the second effective station, thus initially realizing the positioning of the spacecraft return capsule and the positioning of all effective stations among three or more stations. The specific functions and processing of this control unit 200 are further described in step S150.

[0124] This invention provides a solution for determining the real-time position of the return capsule during the landing phase of a manned spacecraft, addressing the difficulties in rendezvous and positioning caused by factors such as large angular measurement errors of landing site imaging equipment, some equipment tracking secondary targets, and various constraints within the landing site. The invention presents a highly robust optical rendezvous and positioning method for the spacecraft return capsule using multiple stations. It generates a set of rendezvous points based on a two-station non-plane rendezvous and positioning method, and utilizes an adaptive spatial filtering method based on a sliding window least squares operator and a target vector angle threshold judgment method to achieve highly robust real-time target fusion positioning, thereby improving the measurement accuracy of the return capsule's real-time position information during the manned spacecraft's landing phase.

[0125] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0126] According to a third embodiment of the present invention, a terminal corresponding to a spacecraft return capsule positioning device is provided, comprising: the spacecraft return capsule positioning device described above.

[0127] Since the processing and functions implemented by the terminal in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0128] According to a fourth embodiment of the present invention, a storage medium corresponding to a spacecraft return capsule positioning method is provided. The storage medium includes a stored program, wherein the program controls the device where the storage medium is located to execute the spacecraft return capsule positioning method described above when it is running.

[0129] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0130] According to a fifth embodiment of the present invention, a computer program product corresponding to the spacecraft return capsule positioning method is provided, comprising a computer program that, when executed by a processor, implements the steps of the spacecraft return capsule positioning method described above.

[0131] Since the processing and functions implemented by the computer program product in this embodiment are basically corresponding to the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0132] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0133] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for locating a spacecraft return capsule, characterized in that, This method is applied to optical rendezvous and positioning of the spacecraft's return capsule from three or more stations; the spacecraft return capsule positioning method includes: Mark all stations out of three or more stations as valid stations, and denote it as the first valid station; For the first effective station, obtain the angle measurement data of each station in the first effective station, and thus obtain the angle measurement data of the first effective station; For the first effective station, based on the angle measurement data of every two stations in the first effective station, perform two-station skew intersection to obtain the intersection point set of the first effective station, which is denoted as the first intersection point set; For the first set of intersection points, a sliding window least squares operator is used to generate an adaptive spatial filtering region, which automatically filters out outlier intersection points in the first set of intersection points. After denoising and smoothing, the continuous intersection results of the first effective station are obtained, and the first continuous intersection results are obtained. Based on the first continuous rendezvous results and the angle measurement data of each station in the first effective station, the validity of the angle measurement data of each station in the first effective station is determined, so as to identify a new effective station in the first effective station, which is recorded as the second effective station, thus initially realizing the positioning of the spacecraft return capsule and the positioning of all effective stations among three or more stations.

2. The spacecraft return capsule positioning method according to claim 1, characterized in that, Also includes: After identifying a new effective station in the first effective station and designating it as the second effective station, the angle measurement data of each station in the first effective station are re-acquired for the first effective station, thereby obtaining the angle measurement data of the first effective station again. For the angle measurement data of the second effective station and the re-obtained first effective station, perform two-station skew intersection based on the angle measurement data of every two stations in the second effective station. In this way, the intersection point set of the second effective station is obtained, which is denoted as the second intersection point set. For the second intersection point set, a sliding window least squares operator is used to generate an adaptive spatial filtering region, which automatically filters out outlier intersection points in the second intersection point set. After denoising and smoothing, the continuous intersection results of the second effective station are obtained, thus obtaining the second continuous intersection results. Based on the second continuous rendezvous results and the angle measurement data of each station in the first effective station, the validity of the angle measurement data of each station in the first effective station is determined, so as to re-determine the new effective station in the first effective station, which is recorded as the third effective station, and further realize the positioning of the spacecraft return capsule and the positioning of the effective stations in all three or more stations; This process is repeated to achieve the positioning of the spacecraft's return capsule and the positioning of all valid stations among three or more tracking stations.

3. The spacecraft return capsule positioning method according to claim 1 or 2, characterized in that, For the first effective station, based on the angular measurement data of every two stations within the first effective station, perform skew intersection between the two stations. This yields the intersection point set of the first effective station, denoted as the first intersection point set, which includes: For the first effective station, a two-station non-plane intersection method is adopted. The angle measurement data from every two stations in the first effective station are used as one frame of data. A two-station non-plane intersection is performed between every two stations to obtain... There are three intersection points P, where N represents the number of first valid stations and N is a positive integer.

4. The spacecraft return capsule positioning method according to claim 1 or 2, characterized in that, For the first set of intersection points, a sliding window least squares operator is used to generate an adaptive spatial filtering region, automatically filtering out outlier intersection points in the first set of intersection points. After denoising and smoothing, the continuous intersection results of the first effective station are obtained, including: Using the least squares operator with a sliding window, the curve of the intersection point relative to time in the first continuous intersection result is fitted to obtain the center and radius parameters of the sphere, and a spherical spatial screening area is generated. Based on the spherical space screening region, outlier intersection points are screened out from the first intersection point set to obtain a subset of the symbol target range, which is denoted as the reasonable subset; The average value of the reasonable subset is calculated to update the least squares operator. The fitting point of the curve of the intersection point relative to time in the first continuous intersection result is recalculated as the multi-station intersection result of the current frame, and the first continuous intersection result is obtained.

5. The spacecraft return capsule positioning method according to claim 4, characterized in that, Using a sliding window least squares operator, the curve of the intersection point relative to time in the first continuous intersection result is fitted to obtain the sphere center and radius parameters, generating a spherical spatial screening region, including: Using the least squares operator LS(P,t) with a sliding window, the intersection points in the first continuous intersection results are used as sample data, the window data capacity is constant K, and the data entry and exit method is data first-in-first-out. The curve F(t) of the intersection points relative to the time in the first continuous intersection results within a preset window time period is fitted, and the curve derivative v=F′(t) is calculated. For the k-th frame of data, the fitting point of the curve F(t) is... Construct a spherical spatial screening region with center R = D·v·Δt.

6. The spacecraft return capsule positioning method according to claim 1 or 2, characterized in that, Based on the first continuous intersection results and the angle measurement data of each station in the first effective station, the validity of the angle measurement data of each station in the first effective station is determined to identify new effective stations in the first effective station, denoted as the second effective station, including: Calculate the vector of the first continuous intersection result relative to each of the first effective stations, and calculate the angle between the vector and the actual angle vector corresponding to the angle measurement data of each of the first effective stations; Determine whether the angle corresponding to any station in the first valid stations is less than a preset angle threshold: if so, determine that the angle measurement data of any station is valid and it is added as a new valid station in the first valid stations, and record all new valid stations in the first valid stations as second valid stations; otherwise, determine that the angle measurement data of any station is invalid and do not add any station to the second valid stations.

7. A spacecraft return capsule positioning device, characterized in that, An optical rendezvous and positioning device for three or more stations on a spacecraft return capsule; the spacecraft return capsule positioning device includes: The control unit is configured to mark all three or more stations as valid stations, and designate them as the first valid station. The acquisition unit is configured to acquire angle measurement data of each station in the first effective station, thereby obtaining the angle measurement data of the first effective station; The control unit is further configured to perform two-station skew intersection based on the angle measurement data of every two stations in the first effective station, thereby obtaining the intersection point set of the first effective station, denoted as the first intersection point set; The control unit is further configured to use a sliding window least squares operator to generate an adaptive spatial filtering region for the first intersection point set, automatically filter out outlier intersection points in the first intersection point set, and perform denoising and smoothing processing to obtain the continuous intersection results of the first effective station, thus obtaining the first continuous intersection result. The control unit is further configured to determine the validity of the angle measurement data of each station in the first effective station based on the first continuous rendezvous result and the angle measurement data of each station in the first effective station, so as to determine a new effective station in the first effective station, which is denoted as the second effective station, and to initially realize the positioning of the spacecraft return capsule and the positioning of the effective stations among all three or more stations.

8. A terminal, characterized in that, include: The spacecraft return capsule positioning device as described in claim 7.

9. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the spacecraft return capsule positioning method according to any one of claims 1 to 6.

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

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