Aircraft trajectory ray tracing data extraction method based on time delay sorting and threshold value screening
By using time delay sorting and threshold filtering, the problem of redundant paths in ray tracing data is solved, and representative paths are efficiently selected, improving the accuracy and computational efficiency of channel modeling. This method is applicable to channel modeling for hypersonic vehicles, reentry vehicles, and near-space communications.
Patent Information
- Application Number
- CN202511848478.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-09
- Publication Date
- 2026-02-13
AI Technical Summary
Existing technologies cannot efficiently select representative paths when dealing with large and complex ray tracing results, resulting in excessive computational burden and inaccurate channel feature extraction. Especially in the electromagnetic propagation environment of hypersonic and near-space vehicles, existing methods lack time-delay domain discrimination, making it difficult to distinguish similar paths, resulting in too many redundant paths and increasing modeling complexity.
A time-delay sorting and threshold filtering method is adopted. By sorting the ray paths by time delay and judging differences, independent paths are selected and redundant paths are eliminated. The physical constraints of ray propagation are used to ensure the compactness and representativeness of the path set.
It significantly reduces redundant paths, improves the accuracy and computational efficiency of channel modeling, forms a clear channel multipath structure, facilitates communication performance analysis and system design, and enhances the reliability and accuracy of engineering design.
Smart Images
Figure CN121522752A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of channel modeling and data extraction, and relates to ray tracing data screening and extraction under a flight trajectory, in particular to a flight vehicle trajectory ray tracing data extraction method based on time delay sorting and threshold screening. BACKGROUND
[0002] In a large and complex ray tracing result, each flight trajectory point will generate hundreds or even thousands of candidate ray paths. Among these paths, there are not only effective paths related to the aircraft receiving area, but also a large number of redundant, repeated or approximately equivalent paths, such as Figure 2 Ray 2-1 and 2-2 shown in FIG. 2, such ray paths are highly similar in geometric space and can be considered as approximately equivalent paths of a certain multipath component. If these data are directly used without screening, not only will the calculation burden of subsequent channel modeling and simulation be significantly increased, but also the channel feature extraction will be inaccurate and difficult to reflect the physical propagation law. To avoid redundant data and improve calculation efficiency, only one representative path needs to be retained.
[0003] Therefore, one of the current technical problems to be solved is to screen an optimal path from multiple similar paths and automatically distinguish mutually independent non-similar paths.
[0004] Currently, existing research mainly determines the effectiveness of a ray by manually judging whether the ray enters the receiving area of the aircraft. However, this method has the following limitations: Low screening efficiency: The manual screening method has low processing efficiency for large-scale simulation data and cannot meet the large batch simulation demand.
[0005] Lack of time delay domain discrimination: It is difficult to distinguish paths that are similar in geometric space but have significant time delay differences, which may lead to the loss of effective multipaths.
[0006] Too many redundant paths: For multiple rays that are highly similar in geometry and have similar time delays, all of them will be retained, resulting in high modeling complexity.
[0007] With the development of hypersonic aircraft, near-space aircraft and re-entry aircraft, the complex electromagnetic propagation environment (ionosphere) in which they fly during flight puts higher requirements on communication systems. Ray tracing (Ray Tracing) is an important tool for analyzing the propagation of electromagnetic waves in the ionosphere and atmospheric environment, which can provide large-scale channel parameter data covering the entire flight area, such as propagation time delay, multipath paths and spatial distribution. These data are of great significance for analyzing the stability of aircraft communication links, channel time delay spread characteristics and anti-interference capability.
[0008] The most common method in the prior art is to determine whether the ray falls into the receiving area of the aircraft based on a geometric receiving window, that is, to manually or rule-determine whether the ray falls into the receiving area of the aircraft.
[0009] However, the problem is that only relying on geometric space determination lacks the constraint of the time delay domain, similar paths are difficult to distinguish, manual screening or simple rule screening is low in efficiency and cannot support batch modeling tasks in large-scale simulation, and redundant paths cannot be merged, resulting in large consumption of computing resources and bloated simulation results. SUMMARY
[0010] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a method for extracting aircraft trajectory ray tracing data based on time delay sorting and threshold screening, which can improve the accuracy of channel modeling: by sorting the ray paths by time delay and distinguishing the differences, it is ensured that independent paths and approximately equivalent paths can be effectively distinguished, and the extraction result is more in line with physical laws. Reduce the complexity of subsequent calculation: with the help of threshold screening mechanism, redundant or highly similar ray paths are merged, invalid data is reduced, and the efficiency of subsequent calculation is improved. Enhance the physical interpretability: keep representative propagation paths, form a simple and clear channel multipath structure, and facilitate subsequent communication performance analysis and system design.
[0011] In order to achieve the above purpose, the technical scheme adopted by the present application is: The method for extracting aircraft trajectory ray tracing data based on time delay sorting and threshold screening comprises the following steps: Step 1, initialization: For each aircraft trajectory point, an empty effective path set is established; Step 2, data determination: If the trajectory point has no ray path data, skip to the next flight trajectory point; Step 3, time delay sorting: If the flight trajectory point has ray path data, sort all ray paths received by the flight trajectory point in ascending order of propagation time delay; Step 4, threshold screening: When the time delay difference between the adjacent two ray paths of the flight trajectory point is greater than the set threshold, the previous path is determined as an effective path; when the time delay difference is less than the threshold, the path with the shortest distance from the ray endpoint to the trajectory point is selected and replaced; Step 5, final path check: For the last ray path, if the time delay difference between the last ray path and the previous effective ray path is greater than the threshold , the last ray path is added to the effective path set, and the effective path set constitutes the aircraft trajectory ray tracing data.
[0012] The step 1 is specifically: initializing the effective path set: For each i ∈{1,2,…, N r}, j ∈{1,2,…, M i}initialization:
[0013] That is, each flight trajectory point i Initialize an empty set of valid paths; j: the first... j Index of the rays; M i : No. i The total number of ray paths that fall within the geometric region of the aircraft at each flight trajectory point; F i The selected first i The set of effective ray paths under each flight trajectory point.
[0014] Step 2 specifically involves: Determine if ray path data exists. Skip the current trajectory point to the next spacecraft trajectory point; otherwise continue, C i : No. i The set of all received ray paths under each flight trajectory point; like C i No data, empty ( If the ray data is not present, then no ray data exists; otherwise, it exists.
[0015] Step 3 specifically involves: Will C i All ray paths in the middle are arranged according to propagation time delay τ i,j Sort in ascending order.
[0016] Step 4 specifically involves: Selecting an effective path based on latency threshold and nearest distance: Set counter k =1, start traversing from the path j=2. C i : like
[0017] The current path is considered to have a significantly different latency from the previous path, and is thus regarded as a different path; the previous path is then considered... As a valid path:
[0018] τ i,j : No. i The flight trajectory point and the first j Time delay under a single ray; τ i,j-1 : No. i The flight trajectory point and the first j- Time delay under one ray; The latency threshold is a key criterion for determining whether there is an approximate equivalence. Its value can be set in conjunction with the latency resolution of the communication system. For the first i The first flight trajectory point k Channel data for each effective ray path; r i,j-1 : No. i The flight trajectory point and the first j- Channel data under one ray; k : No. k One effective ray path.
[0019] Otherwise, if the time delay difference between the current path and the previous path is small, they are considered similar paths; in this case, the path whose endpoint is closest to the trajectory point is selected and replaced: if but r i,j = r i,j ,otherwise r i,j = r i,j-1 .
[0020] Step 5 specifically involves: checking and adding the last path. like M i >1 and the propagation delay of the last path satisfies the delay difference condition with the selected last path:
[0021] Then the last path Added as a valid path: ; τ i,Mi : No. i The flight trajectory point and the first M i Time delay under a single ray; || Absolute value symbol; τi,k-1 : No. i The flight trajectory point and the first k Time delay under -1 effective ray path; For the first i The first flight trajectory point k Channel data for each effective ray path; r i,Mi : No. i The flight trajectory point and the first M i Channel data under each ray.
[0022] The entire ray-tracing data of the aircraft trajectory is N r The set of all received ray paths for each flight trajectory point C After filtering and extraction, the set of valid paths F under the aircraft trajectory is obtained. N r The set of all received valid ray paths for each flight trajectory point.
[0023] The path set obtained by the method serves as a high-quality input for subsequent multipath analysis, channel modeling, and communication link evaluation.
[0024] The ray path set obtained by the method is used for shortwave channel modeling of hypersonic vehicles, reentry vehicles, and near-space communications.
[0025] The beneficial effects of this invention are: This invention first sorts the multipath paths obtained from ray tracing according to their propagation delay. The principle is based on the fundamental law of electromagnetic wave propagation: path length and propagation delay are strictly positively correlated. By utilizing this physical constraint, the originally disordered multipath data is rearranged into a path sequence with a clear sequential relationship, accurately representing the propagation hierarchy between different paths. This step avoids paths belonging to the same reflection mechanism from being intertwined and mixed in the data structure, improving the resolvability of multipath data from the source and providing a reliable physical basis for subsequent screening and judgment.
[0026] After completing the time delay sorting, this invention further introduces a spatial threshold screening mechanism. This mechanism is based on the principle of spatial continuity of ray propagation: paths with the same propagation mechanism (such as a single reflection or refraction) should maintain similar spatial geometric characteristics and avoid abrupt shifts. Therefore, this invention sets a discrimination threshold based on the time delay difference between adjacent paths: if the time delay difference between two adjacent paths is greater than a preset threshold, they are considered to belong to different propagation clusters and should be retained simultaneously; if the time delay difference is less than the threshold, they are determined to belong to the same propagation cluster, and within that cluster, the closest path is selected as the representative path based on the spatial distance between the path and the geometric center of the spacecraft. Through this "cluster-based selection" method, redundant paths can be effectively eliminated, retaining the path that best reflects the true propagation structure.
[0027] By combining delay sorting and spatial filtering, this invention significantly reduces the probability of redundant paths being added to the effective path set. Redundant paths typically exhibit structures similar to the main propagation path, but their physical meaning is weak, and their delay or spatial location is unstable. Directly retaining them would increase the computational burden of channel modeling and simulation, and may introduce erroneous multipath characteristics, affecting the accuracy of channel analysis results. This method uses dual criteria to accurately eliminate these abnormal paths that do not conform to the propagation mechanism.
[0028] More importantly, this invention can stably and reliably preserve representative propagation paths. In the technical context of this invention, a "representative path" refers to an actual effective path that accurately reflects the physical mechanism of ray propagation. The primary characteristic of such paths is typically that their propagation mechanism is clear, for example, they can correspond to transmission modes with a clear physical source, such as direct paths, primary reflection paths, and secondary reflection paths.
[0029] In summary, this invention, based on a dual mechanism of "time-delay sorting + threshold filtering," fully utilizes the two types of physical constraints in ray propagation to perform structured extraction and physical consistency filtering of complex ray tracing data. This method effectively avoids the erroneous addition of redundant paths and stably retains the most representative set of valid paths, thereby significantly improving the accuracy, stability, and usability of ray data in engineering analysis.
[0030] The path set obtained using this invention exhibits higher compactness, consistency, and physical reliability, serving as a high-quality input for subsequent multipath analysis, channel modeling, and communication link evaluation. This improves the reliability and accuracy of channel characteristic research and engineering design, reduces invalid path involvement, and lowers the computational load for modeling and simulation. It can be applied to shortwave channel modeling for hypersonic vehicles, reentry vehicles, and near-space communications. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the process of the present invention.
[0032] Figure 2 This is a geometric diagram illustrating the technical background.
[0033] Figure 3 This is a schematic diagram of the results before the extraction algorithm of this invention is used.
[0034] Figure 4 This is a schematic diagram of the results after using the extraction algorithm of this invention. Detailed Implementation
[0035] The present invention will now be described in further detail with reference to the accompanying drawings.
[0036] like Figure 1 As shown in the figure, the present invention proposes a method for extracting ray tracing data of aircraft trajectories based on time delay sorting and threshold filtering, as follows: enter: : The set of all received ray paths at the i-th flight trajectory point, where each ray path Includes the location of the ray point closest to the aircraft. and propagation delay Channel data, i Let i be the index of the i-th flight trajectory point. j For the first j Index of the rays; The aircraft at the trajectory point i The geometric center coordinates at time; The latency threshold is a key criterion for determining whether there is an approximate equivalence. Its value can be set in conjunction with the latency resolution of the communication system. N r Total number of spacecraft trajectory points; M i The total number of ray paths falling within the geometric region of the aircraft.
[0037] Output: The selected first i The set of effective ray paths for each trajectory point, among which For the first i The first flight trajectory point k Channel data under valid paths ， This is the extracted valid path index. K i The total number of valid paths after ray data extraction.
[0038] The specific steps of the algorithm are as follows: Step 1: Initialize the set of valid paths: For each i ∈{1,2,…, N r}, j ∈{1,2,…, M i}initialization:
[0039] That is, each flight trajectory point i Initialize an empty set of valid paths.
[0040] Objective: By establishing an independent set of effective paths for each aircraft trajectory point, we can ensure that subsequent screening and processing have strict consistency and controllability in the trajectory dimension, laying the foundation for independent multipath structure analysis of different trajectory points.
[0041] Effect: Ensures structured management of path selection, avoids data mismatch caused by mixing multiple trajectory points and paths, and provides necessary data isolation for subsequent path sorting and filtering.
[0042] Step 2: Determine if ray path data exists. If the current trajectory point is skipped, proceed to the next spacecraft trajectory point; otherwise, continue.
[0043] Objective: To avoid redundant processing when there is no data or the data is abnormal, and to improve the overall algorithm execution efficiency.
[0044] Effect: Reduces invalid calculations and ensures that the algorithm remains stable even when the path is lost, without affecting the overall trajectory processing flow.
[0045] Step 3: Put C i All ray paths in the middle are arranged according to propagation time delay τ i,j Sort in ascending order.
[0046] Objective: The propagation delay is strictly positively correlated with the geometric length of the ray path. By arranging the delays in ascending order, the propagation hierarchy of the ray in physical space can be restored, and the physical order of the path from near to far and from direct to higher-order reflection can be reconstructed.
[0047] Effect: Eliminates the problem of disordered order in the original ray data, giving the subsequent discrimination mechanism based on "difference between adjacent paths" a clear physical basis, and improving the accuracy of path classification and cluster division.
[0048] Step 4: Select the effective path based on latency threshold and nearest distance: Set counter k =1, start traversing from the path j=2.C i : like
[0049] If the current path has a significantly different latency from the previous path, it is considered a different path. The previous path... As a valid path:
[0050] Otherwise, if the time delay difference between the current path and the previous path is small, they are considered similar paths. In this case, the path whose endpoint is closest to the trajectory point is selected and replaced. if but r i,j = r i,j ,otherwise r i,j = r i,j-1 .
[0051] Objective: Within the same physical cluster, different paths may have slight geometrical drift. By selecting the path whose endpoint is closer to the spacecraft's location, the "most realistic and representative" path within the cluster can be chosen.
[0052] Effect: Redundancy removal and optimal retention of paths within the same cluster are achieved, eliminating noisy paths with unstable spatial locations and weak physical meaning, ensuring that the final output path set is more compact and representative.
[0053] Step 5: Check and add the last path. like M i >1 and the propagation delay of the last path satisfies the delay difference condition with the selected last path:
[0054] Then the last path Added as a valid path: .
[0055] Objective: To ensure that no independent path clusters at the end of the path list are missed due to the termination of traversal, and to achieve complete identification of the full path structure.
[0056] Effect: Prevents the last type of propagation mechanism from being missed, further improving the completeness and physical consistency of path extraction results.
[0057] Appendix Figure 3The figure shows the set of all ray paths received when the aircraft trajectory point is located at a certain position without the processing method of this invention. As can be seen from the figure, a total of 6 ray paths are received at this position, some of which have significant spatial overlap with other paths and are considered redundant paths with weak physical significance.
[0058] Appendix Figure 4 The diagram shows the path set obtained after applying the ray tracing data extraction method based on time delay sorting and threshold filtering described in this invention. It can be seen that invalid or redundant paths have been automatically removed after processing, retaining only four representative effective paths with clear propagation mechanisms. This results in a clearer, more stable path structure that conforms to the laws of electromagnetic propagation. A comparison diagram before and after ray tracing data extraction is provided.
[0059] The "delay sorting + delay threshold + spatial distance" joint discrimination system formed by the steps of this invention can achieve the following technical effects: (1) Restore the physical order: Delay sorting re-establishes the physical hierarchy of multipath paths, making multipath data parseable instead of unordered.
[0060] (2) Accurate cluster-level differentiation: The time delay threshold effectively distinguishes different propagation mechanisms, ensuring that path clustering conforms to the physics of electromagnetic wave propagation.
[0061] (3) Redundancy removal within the same cluster: The selection mechanism based on geometric distance ensures that only the most representative path is retained in each cluster.
[0062] (4) Avoid adding redundant paths by mistake: It can eliminate interference paths that have drifted reflection points, unstable end space, or weak physical meaning.
[0063] (5) Obtain a compact, stable, and reliable high-quality path set: The final path set is more physically consistent, stable, and engineering-applicable, significantly improving the reliability of channel analysis, communication simulation, and engineering design.
[0064] This invention solves the problem that manual screening is inefficient in processing large-scale simulation data and cannot meet the needs of large-scale simulation. This invention addresses the problem of losing effective multipath paths due to the inability to distinguish between geometrically similar paths with significant time delay differences. This invention addresses the problem that multiple rays that are geometrically similar and have similar time delays are still all retained, leading to excessive complexity in subsequent modeling.
Claims
1. A method for extracting ray tracing data of aircraft trajectories based on time delay sorting and threshold filtering, characterized in that, Includes the following steps; Step 1: For each aircraft trajectory point, establish an empty set of valid paths; Step 2: If there is no ray path data for the trajectory point, skip to the next flight trajectory point; Step 3: If the flight trajectory point has ray path data, sort all the ray paths received by the flight trajectory point; Step 4: When the time delay difference between two adjacent ray paths of the flight trajectory point is greater than the set threshold, the former path is identified as a valid path; when the time delay difference is less than the threshold, the ray path whose endpoint is closest to the flight trajectory point is selected and replaced. Step 5: For the last ray path, if the difference between its delay and the previous valid ray path is greater than the threshold... If the path is found, it is added to the set of valid paths, and the set of valid paths constitutes the ray tracing data of the aircraft trajectory.
2. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 1, characterized in that, Step 1 specifically involves: initializing the set of valid paths. For each i ∈{1,2,…, N r }, j ∈{1,2,…, M i }initialization: That is, each flight trajectory point i Initialize an empty set of valid paths; j: the first... j Index of the rays; M i : No. i The total number of ray paths that fall within the geometric region of the aircraft at each flight trajectory point; F i The selected first i The set of effective ray paths under each flight trajectory point.
3. The method for extracting aircraft trajectory ray tracing data based on time delay sorting and threshold filtering according to claim 2, characterized in that, Step 2 specifically involves: Determine if ray path data exists: If Skip the current trajectory point to the next flight trajectory point; otherwise continue. C i : No. i The set of all received ray paths under each flight trajectory point; like C i No data, empty ( If the ray data is not present, then no ray data exists; otherwise, it exists.
4. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 3, characterized in that, Step 3 specifically involves: Will C i All ray paths in the middle are arranged according to propagation time delay τ i,j Sort in ascending order from smallest to largest.
5. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 4, characterized in that, Step 4 specifically involves: Selecting an effective path based on latency threshold and nearest distance: Set counter k =1, start traversing from the path j=2. C i : like ; The current path is considered to have a significantly different latency from the previous path, and is thus regarded as a different path; the previous path is then considered... As a valid path: τ i,j : No. i The flight trajectory point and the first j Time delay under a single ray; τ i,j-1 : No. i The flight trajectory point and the first j- Time delay under one ray; The latency threshold is a key criterion for determining whether there is an approximate equivalence. Its value can be set in conjunction with the latency resolution of the communication system. For the first i The first flight trajectory point k Channel data for each effective ray path; r i,j-1 : No. i The flight trajectory point and the first j- Channel data under one ray; k : No. k One effective ray path.
6. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 5, characterized in that, If the delay difference between the current path and the previous path is small, they are considered similar paths. In this case, select the path whose endpoint is closest to the trajectory point and replace it: if but r i,j = r i,j ,otherwise r i,j = r i,j-1 .
7. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 6, characterized in that, Step 5 specifically involves: Check and add the last path: like M i >1 and the propagation delay of the last path satisfies the delay difference condition with the selected last path: Then the last path Added as a valid path: ； τ i,Mi : No. i The flight trajectory point and the first M i Time delay under a single ray; || Absolute value symbol; τ i,k-1 : No. i The flight trajectory point and the first k Time delay under -1 effective ray path; For the first i The first flight trajectory point k Channel data for each effective ray path; r i,Mi : No. i The flight trajectory point and the first M i Channel data under each ray.
8. The method for extracting ray tracing data of aircraft trajectory based on time delay sorting and threshold filtering according to claim 7, characterized in that, The ray tracing data of the aircraft trajectory is all N r The set of all received ray paths for each flight trajectory point C After filtering and extraction, the set of valid paths F under the aircraft trajectory is obtained. N r The set of all received valid ray paths for each flight trajectory point.
9. An application of the aircraft trajectory ray tracing data extraction method based on time delay sorting and threshold filtering as described in any one of claims 1-8, characterized in that, The path set obtained by the method serves as a high-quality input for subsequent multipath analysis, channel modeling, and communication link evaluation.
10. An application of the aircraft trajectory ray tracing data extraction method based on time delay sorting and threshold filtering as described in any one of claims 1-8, characterized in that, The method obtains path sets for shortwave channel modeling of hypersonic vehicles, reentry vehicles, and near-space communications.