Vehicle-mounted multi-frequency transmitting and receiving system for short-wave signal

Abstract

This invention relates to the field of signal processing technology, specifically to a vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system. In this invention, a data acquisition module first acquires the reception data corresponding to each frequency point. Then, a propagation fingerprint construction module combines the time sequence of the reception data with the polling order corresponding to a set frequency sequence to construct a multi-frequency time-series correlation propagation fingerprint and determine the time offset relationship. Subsequently, a disturbance correction module extracts synchronization change features, generates common-mode components, and corrects the reception data to obtain corrected multi-frequency reception results. A consistency feature extraction module further extracts path evolution consistency features, and a path determination module determines whether the propagation path corresponding to each frequency point is valid and generates a reliability ranking result. Finally, a result output module determines the target reception frequency point and outputs the propagation state determination result, thereby helping to distinguish between cross-frequency synchronization changes caused by vehicle mobility and the evolution changes of the propagation path itself at each frequency point.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, specifically to a vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system. Background Technology

[0002] Shortwave communication relies on complex propagation environments to achieve long-distance signal transmission, with the propagation link state fluctuating with changes in time, spatial location, and external environment. In vehicle applications, the communication platform is in a continuous state of motion, and the propagation conditions of the transceiver equipment constantly change with the vehicle's position, speed, and attitude. To obtain currently available propagation frequencies, vehicle-mounted shortwave communication systems typically perform transmission and reception tests on multiple designated frequencies and determine whether the propagation path meets the communication requirements based on the reception data at each frequency.

[0003] Because it is difficult for a vehicle-mounted platform to maintain a static propagation environment during maneuvering, the data obtained from multi-frequency reception not only includes information on the changes in the propagation path of each frequency point, but also includes common fluctuation information caused by changes in the platform's motion state. Furthermore, multi-frequency reception is typically performed sequentially according to a set frequency sequence, and the timing of data collection at different frequencies varies, resulting in inconsistencies in the time reference of the received data. When the system directly uses the received data from each frequency point to determine the validity of the propagation path, the time misalignment caused by polling and the common fluctuations generated during maneuvering can affect the identification of the propagation evolution trend of each frequency point, causing short-term anomalies or synchronization disturbances at some frequencies to be included in the path determination criteria.

[0004] Therefore, under the conditions of continuous vehicle operation and multi-frequency sequential reception and testing, how to form correlation information that can reflect the evolution of the propagation state of each frequency point from the multi-frequency reception and testing data, and thereby improve the consistency of the judgment of the effectiveness of the propagation path, has become an issue that needs to be addressed in vehicle-mounted shortwave multi-frequency reception and testing. Summary of the Invention

[0005] The purpose of this invention is to provide a vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system to solve the problems mentioned in the background art. The specific technical problems include how to distinguish between cross-frequency synchronization changes caused by vehicle mobility and the evolution changes of the propagation path of each frequency point based on the time sequence and polling order of each frequency point during multi-frequency polling reception, so as to solve the problem that the determination of the target reception frequency point in vehicle-mounted mobile shortwave multi-frequency reception is easily affected by time misalignment and common disturbances.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system, comprising a reception data acquisition module, a propagation fingerprint construction module, a disturbance correction module, a consistency feature extraction module, a path determination module, and a result output module, wherein: The reception and reception data acquisition module performs multi-frequency transmission and reception tests on the vehicle platform according to a set frequency sequence, acquiring the reception and reception data corresponding to each frequency; specifically including: According to the set frequency sequence, the vehicle-mounted transmitter and the vehicle-mounted receiver switch frequencies in sequence, so that the vehicle-mounted transmitter transmits shortwave test signals at each frequency and the vehicle-mounted receiver collects the propagation response signal in the receiving channel corresponding to each frequency. The vehicle-mounted receiver acquires multiple sampling points within the sampling window corresponding to each frequency point, and performs an average value calculation on the multiple sampling points to obtain the received and measured data for that frequency point; The time synchronization circuit records the corresponding acquisition time when the acquisition is completed at each frequency point, thereby forming the time sequence of the received and measured data. Output the received data for each frequency point, as well as the time sequence corresponding to the received data and the polling order corresponding to the set frequency point sequence; The received data includes the received signal strength, group delay, and multipath spread.

[0007] The receiving and receiving data acquisition module is used to perform multi-frequency transmission and reception tests on the vehicle platform according to a set frequency point sequence. It acquires the received signal strength value, group delay value, and multipath spread value within the sampling window corresponding to each frequency point, and records the acquisition time when each frequency point completes acquisition, thereby forming a correspondence between the receiving and receiving data, time sequence, and polling order. Through this receiving and receiving data acquisition module, subsequent processing can not only utilize the propagation response signal itself of each frequency point, but also retain the time information generated by the frequency point switching sequence during multi-frequency polling reception and testing. This provides a data foundation for subsequent identification of polling time difference, establishment of a unified time reference, and differentiation of cross-frequency point synchronous changes based on time sequence and polling order, thereby helping to reduce the dependence of target receiving and receiving frequency point determination on the original receiving and receiving data at a single moment.

[0008] The propagation fingerprint construction module constructs a multi-frequency time-series correlation propagation fingerprint based on the received and tested data, the corresponding time order of the received and tested data, and the polling order corresponding to the set frequency point sequence, and determines the time offset relationship; the construction process of the multi-frequency time-series correlation propagation fingerprint specifically includes: Arrange the received data at each frequency point in chronological order within a receiving period to generate an ordered receiving sequence; Write the polling position of each frequency point in the set frequency point sequence into the ordered receiving and testing sequence, so that each group of receiving and testing data has frequency point identity and polling position information; The received signal strength, group delay, and multipath spread values ​​at each frequency point are normalized, and a propagation state vector is constructed according to a fixed field order. The propagation state vectors of each frequency point are written into the propagation fingerprint structure in time order and polling order to form a multi-frequency time-series associated propagation fingerprint; Each record of the multi-frequency time-series correlation propagation fingerprint includes a frequency point identifier, a polling location identifier, a collection time identifier, and a propagation state vector.

[0009] The process of determining the time offset relationship specifically includes: Read the acquisition times of each frequency point recorded by the time synchronization circuit; The local time offset between adjacent frequency points is determined based on the acquisition time of adjacent frequency points, and the local time offset between each adjacent frequency point is written into the time offset relationship table in sequence. Using the start time of the current reception and testing cycle as a unified reference time, determine the global offset of each frequency point relative to the unified reference time; Among them, the local time offset is used to describe the local time difference caused by polling switching, and the global offset is used for subsequent time alignment and time compensation.

[0010] The propagation fingerprint construction module is used to construct a multi-frequency time-series associated propagation fingerprint based on the received and measured data, the corresponding time order of the received and measured data, and the polling order corresponding to the set frequency point sequence, and to determine the time offset relationship. This module normalizes the received signal strength value, group delay value, and multipath spread value of each frequency point into a propagation state vector. Simultaneously, it writes the frequency point identifier, polling position identifier, and acquisition time identifier into the same propagation fingerprint structure, so that the propagation state of each frequency point is no longer used as isolated data for judgment, but is associated with its acquisition order and polling position in multi-frequency polling and receiving. By determining the local time offset and global offset, a basis can be provided for subsequent time alignment and time compensation, helping to reduce the impact of state misalignment caused by inconsistent acquisition times of different frequencies on path evolution judgment.

[0011] The perturbation correction module extracts synchronization change features from the multi-frequency time-series correlation propagation fingerprint. The extraction process of synchronization change features specifically includes: Based on the time offset relationship, the propagation state vectors of each frequency point in the multi-frequency time-series correlation propagation fingerprint are time-aligned so that the propagation state values ​​of different frequencies correspond to a unified reference time. Calculate the state change of the propagation state vector for each frequency point in adjacent reception and measurement cycles; Perform directionality and amplitude judgment on state changes at multiple frequency points; When multiple frequency points meet the conditions of unidirectional change and minimum change within the same time period, the common change segment is extracted as a synchronous change feature. Among them, the synchronous change characteristics are recorded in the form of time period, frequency point group and change vector group.

[0012] Common-mode components are generated based on synchronous change characteristics, specifically including: The state change vector in the synchronous change characteristics is aggregated by dimension to obtain the common mode component of the corresponding measurement period; The common-mode component is a three-dimensional vector with the same dimension as the propagation state vector; In each dimension, the multiple frequency point changes are sorted by numerical value, the maximum and minimum values ​​are removed, and the remaining changes are averaged to obtain the common mode change value for that dimension. When there is no frequency point that participates in the calculation of common-mode components, the common-mode components of the corresponding receiving and measuring period are set to zero vectors; The zero vector is a three-dimensional vector with the same dimension as the corresponding state vector.

[0013] The received and measured data are corrected based on the time offset relationship and common-mode components to obtain the corrected multi-frequency received and measured results, which specifically include: Time compensation is performed on the original received and measured data of each frequency point according to the time offset relationship, and the received and measured data of different frequency points are mapped to a unified reference time. After completing time compensation, the common-mode component is subtracted from the propagation state vector of each frequency point to obtain the correction result of each frequency point after disturbance suppression. The corrected propagation state vectors at each frequency point are restored to the corrected received signal strength value, corrected group delay value, and corrected multipath spread value according to the correspondence with the original parameters, thus forming the corrected multi-frequency reception and measurement results; Among them, the corrected multi-frequency reception and measurement results characterize the propagation status of each frequency point after eliminating the polling time difference and the influence of common disturbances.

[0014] The disturbance correction module is used to extract synchronization change features from the multi-frequency time-series correlation propagation fingerprint, generate common-mode components based on the synchronization change features, and correct the received and measured data according to the time offset relationship and the common-mode components to obtain the corrected multi-frequency reception and measurement results. The disturbance correction module first maps the propagation state values ​​of different frequencies to a unified reference time according to the time offset relationship, then calculates the state change amount of the propagation state vector in adjacent reception and measurement cycles, and extracts the common change segment through the same direction judgment and amplitude judgment, thereby forming the synchronization change features used to characterize the cross-frequency synchronous change. Furthermore, by aggregating by dimension to generate common-mode components, and subtracting the common-mode components from the propagation state vectors of each frequency after completing time compensation, it can suppress the common disturbances caused by vehicle movement to a certain extent, so that the corrected multi-frequency reception and measurement results focus more on reflecting the evolution and change of the propagation path of each frequency, thereby providing a more stable input for the determination of the target reception and measurement frequency.

[0015] The consistency feature extraction module adjusts the multi-frequency time-series correlation propagation fingerprint based on the corrected multi-frequency measurement and reception results, and extracts consistency features from the adjusted multi-frequency time-series correlation propagation fingerprint extraction path; specifically including: Read the corrected multi-frequency reception and measurement results, replace the corresponding position data in the original multi-frequency time-series associated propagation fingerprint with the corrected propagation state vector of each frequency point, and update the time-series trajectory in the propagation fingerprint according to a unified time reference. For each frequency point, calculate the length of the continuous hold segment, the deviation between adjacent receiving and receiving cycles, and the trajectory stability of the time-series trajectory. Among them, the continuous holding segment length represents the number of consecutive reception and measurement cycles in which the propagation state of the frequency point maintains the same effective evolution trend, the change deviation between adjacent reception and measurement cycles represents the change amplitude of the propagation state of the frequency point between two adjacent reception and measurement cycles, and the trajectory stability represents the degree of concentration of the time sequence trajectory of the frequency point relative to the central state.

[0016] The consistency feature extraction module replaces the corresponding position data in the original multi-frequency time-series correlation propagation fingerprint with the corrected propagation state vector of each frequency point, and updates the time-series trajectory in the propagation fingerprint according to a unified time reference, so that subsequent analysis is based on the propagation state after time compensation and common-mode component subtraction. By calculating the continuous holding segment length, adjacent reception and measurement cycle variation deviation and trajectory stability for the time-series trajectory corresponding to each frequency point, the evolution and change of the propagation path of each frequency point can be described from the aspects of time continuity, adjacent variation amplitude and state concentration, which helps to distinguish between short-term synchronization disturbances and persistent path evolution characteristics.

[0017] The path determination module determines the validity of the propagation path corresponding to each frequency point based on the consistency characteristics of path evolution, and generates a reliability ranking result; specifically including: Based on the consistency characteristics of path evolution, determine whether the following conditions are met for each frequency point: Condition A: The length of the continuous segment reaches the length threshold; Condition B: The deviation between adjacent measurement cycles does not exceed the deviation threshold; Condition C: The trajectory stability reaches the path stability threshold; If a frequency point simultaneously satisfies conditions A, B, and C, then the propagation path corresponding to that frequency point is determined to be a valid path. If a frequency does not simultaneously meet conditions A, B, and C, then the propagation path corresponding to that frequency is determined to be an invalid path. The length of the continuous holding segment, the deviation of the adjacent receiving and measuring cycles, and the trajectory stability are normalized respectively, and then weighted and summed according to fixed weights to obtain the path validity judgment value of each frequency point. The frequency points are sorted from high to low according to the path validity judgment value to form a credibility ranking result.

[0018] The path determination module is used to determine the validity of the propagation path corresponding to each frequency point based on the path evolution consistency characteristics and generate a credibility ranking result. This module comprehensively judges the persistence, stability, and concentration of the propagation path at each frequency point by determining whether the length of the continuous hold segment reaches a length threshold, whether the deviation between adjacent reception cycles is not higher than a deviation threshold, and whether the trajectory stability reaches a path stability threshold. Simultaneously, the length of the continuous hold segment, the deviation between adjacent reception cycles, and the trajectory stability are normalized and weighted according to fixed weights to obtain the path validity judgment value. Through the above processing, the credibility ranking result no longer depends solely on the instantaneous reception strength of a certain frequency point, but rather combines the corrected path evolution consistency characteristics for ranking, which helps to reduce the impact of time misalignment and common disturbances on frequency point priority judgment.

[0019] The results output module determines the target receiving frequency based on the confidence ranking results and outputs the propagation state determination result corresponding to the target receiving frequency, specifically including: Read the credibility ranking results and determine the target receiving frequency points; Obtain the path validity determination results and trajectory stability of the target receiving and receiving frequency points; When the target receiving frequency point is determined to be a valid path and the trajectory stability is higher than the state stability threshold, the available state is output. When the target receiving frequency point is determined to be a valid path and the trajectory stability is not higher than the state stability threshold, the fluctuation usable state is output. When the target receiving frequency point is determined to be an invalid path, an unavailable status is output. Output the target receiving frequency, propagation status determination result, credibility ranking result, and path validity determination value.

[0020] The result output module is used to determine the target receiving frequency based on the credibility ranking result and output the propagation status judgment result corresponding to the target receiving frequency. This result output module reads the credibility ranking result, combines it with the path validity judgment result and trajectory stability of the target receiving frequency, and outputs the available status, fluctuating available status, or unavailable status of the target receiving frequency. It also outputs the target receiving frequency, propagation status judgment result, credibility ranking result, and path validity judgment value simultaneously. By associating the propagation status judgment result with the credibility ranking result and path validity judgment value, the selection process of the target receiving frequency can have a clearer temporal correlation basis and consistency judgment basis, which helps to reduce the misjudgment impact caused by the difference in polling acquisition time and cross-frequency synchronization changes in vehicle-mounted mobile shortwave multi-frequency receiving scenarios.

[0021] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a data acquisition module to perform multi-frequency transmission and reception tests on a vehicle-mounted platform according to a set frequency sequence. While acquiring the reception data for each frequency, it simultaneously generates the time sequence of the reception data and the polling order corresponding to the set frequency sequence. A propagation fingerprint construction module writes the reception data, time sequence, and polling order into a multi-frequency time-series correlation propagation fingerprint and determines the time offset relationship. A perturbation correction module performs time alignment on the propagation state vectors of each frequency based on the time offset relationship, extracts synchronization change features, generates common-mode components, and corrects the reception data to obtain corrected multi-frequency reception results. A consistency feature extraction module adjusts the... The invention extracts the path evolution consistency characteristics of the multi-frequency time-series correlation propagation fingerprint; then the path determination module generates the credibility ranking result, and the result output module determines the target receiving frequency and outputs the propagation state determination result. Thus, the invention can associate the propagation state of each frequency with the time sequence and polling order during multi-frequency polling and receiving, which helps to distinguish between cross-frequency synchronous changes caused by vehicle mobility and the evolution changes of the propagation path of each frequency itself, reduces the impact of inconsistent polling acquisition time and common disturbances on the path validity determination value and credibility ranking result, thereby improving the stability and reference value of target receiving frequency determination in vehicle-mounted shortwave multi-frequency receiving and receiving. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the core process of the overall module of the present invention; Figure 2 This is a schematic diagram of the core process of the data acquisition module of the present invention; Figure 3 This is a schematic diagram of the core process of the fingerprint propagation construction module of the present invention; Figure 4 This is a schematic diagram of the core process of the disturbance correction module of the present invention; Figure 5 This is a schematic diagram of the core process of the consistency feature extraction module of the present invention; Figure 6 This is a schematic diagram of the core process of the path determination module of the present invention; Figure 7 This is a schematic diagram of the core process of the result output module of the present invention.

[0023] In the diagram: 100, Receive / Test Data Acquisition Module; 200, Propagation Fingerprint Construction Module; 300, Disturbance Correction Module; 400, Consistency Feature Extraction Module; 500, Path Determination Module; 600, Result Output Module. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Next, please refer to Figure 1 This invention provides a vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system, deployed in a vehicle-mounted shortwave communication platform. The vehicle-mounted shortwave communication platform includes a vehicle-mounted transmitter, a vehicle-mounted receiver, a frequency control circuit, a time synchronization circuit, and a data processing device. The data processing device includes a data acquisition module 100, a propagation fingerprint construction module 200, a disturbance correction module 300, a consistency feature extraction module 400, a path determination module 500, and a result output module 600. Each module is executed by the processor calling program instructions from memory and completes data transmission according to a fixed data flow sequence. The receiver data acquisition module 100 outputs the receiver data, time sequence, and polling order; the propagation fingerprint construction module 200 calls the receiver data, time sequence, and polling order to generate a multi-frequency time-series correlation propagation fingerprint and outputs the time offset relationship; the disturbance correction module 300 calls the multi-frequency time-series correlation propagation fingerprint and time offset relationship to generate corrected multi-frequency receiver results; the consistency feature extraction module 400 calls the corrected multi-frequency receiver results to extract path evolution consistency features; the path determination module 500 calls the path evolution consistency features to generate a confidence ranking result; and the result output module 600 calls the confidence ranking result to output the target receiver frequency and the corresponding propagation state determination result.

[0026] Please see Figure 2 The receiving and receiving data acquisition module 100 performs multi-frequency transmission and reception tests on the vehicle platform according to a set frequency point sequence, and obtains the receiving and receiving data for each frequency point; wherein the set frequency point sequence is composed of multiple discrete frequency points in a fixed order, including the first frequency point in sequence. Second frequency point Third frequency point and the fourth frequency point The set frequency sequence remains unchanged throughout a complete reception and testing period; the polling order is the arrangement order of each frequency point in the set frequency sequence, with the first frequency point... Corresponding to the first round of query bit, the second frequency point Corresponding to the second round of query bit, the third frequency point Corresponding to the third round of query bit, the fourth frequency point This corresponds to the fourth round of querying.

[0027] The process of acquiring the test data specifically includes: The frequency control circuit controls the frequency switching of the vehicle-mounted transmitter and receiver according to the set frequency sequence, so that the vehicle-mounted transmitter is on the first frequency. Transmit a shortwave test signal and set the vehicle-mounted receiver to the first frequency. Acquire the propagation response signal within the corresponding receiving channel; complete the first frequency point acquisition. After receiving the signal, the frequency control circuit switches to the second frequency after a frequency switching interval. And perform the same transmit and receive actions; then sequentially for the third frequency point. and the fourth frequency point The same process is performed until all frequency points within a single reception cycle are received and tested; the frequency switching interval is used to ensure that frequency switching and hardware channel switching are completed. Each frequency point corresponds to a sampling window. The vehicle-mounted receiver acquires multiple sampling points within this window and calculates the average value of these points to obtain the received data for that frequency point. The time synchronization circuit records the corresponding acquisition time when acquisition is completed at each frequency point, thus forming the time sequence of the received data. The received data for each frequency point includes the received signal strength value, group delay value, and multipath spread value. The received signal strength value reflects the signal fading level, the group delay value reflects the overall propagation delay of the propagation path, and the multipath spread value reflects the dispersion of multipath propagation. Therefore, the received data acquisition module 100 outputs the received data for each frequency point, along with the corresponding time sequence and the polling order of the set frequency point sequence.

[0028] Please see Figure 3 The propagation fingerprint construction module 200 constructs a multi-frequency temporal correlation propagation fingerprint based on the received and tested data, the time sequence corresponding to the received and tested data, and the polling order corresponding to the set frequency point sequence, and determines the time offset relationship. The multi-frequency temporal correlation propagation fingerprint is used to describe the propagation characteristic correlation changes of different frequency points in a continuous receiving and testing cycle. Each record includes a frequency point identifier, a polling position identifier, an acquisition time identifier, and a propagation state vector. The frequency point identifier is used to distinguish different frequency point sources, the polling position identifier is used to characterize the execution order of the current frequency point in this receiving and testing cycle, the acquisition time identifier is used to characterize the absolute acquisition time of the data corresponding to the current frequency point, and the propagation state vector is used to characterize the propagation state of the current frequency point at the current acquisition time.

[0029] The construction process of multi-frequency temporal correlation propagation fingerprints specifically includes: First, the received data at each frequency point within a receiving period are arranged in chronological order to generate an ordered receiving sequence; Then, the polling position of each frequency point in the set frequency point sequence is written into the ordered receiving and testing sequence, so that each group of receiving and testing data has a clear frequency point identity and polling position information; Subsequently, a propagation state vector is constructed for the received signal strength value, group delay value, and multipath spread value of each frequency point, and the propagation state vectors of each frequency point are written into the propagation fingerprint structure in time order and polling order, thereby forming a multi-frequency time-series associated propagation fingerprint. The multi-frequency temporal correlation propagation fingerprint gradually expands over multiple consecutive reception and testing cycles, forming a temporal correlation data structure with the reception and testing cycle as the horizontal dimension and the frequency point as the vertical dimension. For any frequency point in any reception and testing cycle, a propagation state vector is generated separately and bound and stored with the frequency point identifier, polling position identifier, and acquisition time identifier of that frequency point.

[0030] The construction process of the propagation state vector specifically includes: First, normalizing the received signal strength value, group delay value, and multipath spread value to unify their dimensions. Since the three have different physical meanings and different numerical ranges, the propagation fingerprint construction module 200 reads the reference lower limit and reference upper limit of each parameter and performs normalization transformations accordingly. Let the received signal strength value, group delay value, and multipath spread value be respectively... , and The corresponding lower reference limits are respectively , and The corresponding reference upper limits are respectively , and The normalization results are as follows: , and The normalization formula is: , in Indicates the parameter sequence number; This indicates the lower limit of the received signal strength reference. This represents the lower limit of the group delay reference. Indicates the lower bound of the multipath extension reference; Indicates the upper limit of the reference for received signal strength. Indicates the upper limit of group latency reference. Indicates the upper limit of the multipath extension reference; This represents the normalized received signal strength value. This represents the normalized group delay value. Represents the normalized multipath expansion value; when the denominator The absolute value is less than the normalized denominator protection threshold. When, the normalized result of this parameter Set to 0; where This represents the normalized denominator protection threshold, and To avoid outliers causing the normalization result to go out of bounds, when At that time, Set to 0; when At that time, Set to 1; when a parameter is missing in the current sampling window, the corresponding parameter value of the previous reception cycle at the same frequency point is called as the replacement value; when the corresponding parameter value of the previous reception cycle is also missing, the average value of the corresponding parameter in the first complete reception cycle after the system starts is called as the replacement value.

[0031] After normalization, the propagation fingerprint construction module 200 arranges the three normalized values ​​according to a fixed field order to form the propagation state vector of the current frequency point; let the propagation state vector be... The propagation state vector is then expressed as: Propagation state vector It is fixed as a three-dimensional ordered vector, with the first dimension corresponding to the received signal strength parameter, the second dimension corresponding to the group delay parameter, and the third dimension corresponding to the multipath spread parameter. By fixing the dimensions and field order, the propagation state vectors of different frequencies and different reception and measurement periods can be directly compared.

[0032] To improve the ability of the propagation state vector to represent the propagation state, weights are added to the three normalized parameters. Let the weighted propagation state vector be... The parameter weights are respectively , and Then we have: ,in Indicates the weight of the received signal strength parameter; Indicates the weight of the group delay parameter; This represents the multipath expansion parameter weights; the parameter weights satisfy: The parameter weights are written to the configuration file during system installation and remain unchanged during task execution. When using weighted propagation state vectors, subsequent time alignment, state change calculation, common mode component generation, and trajectory analysis are all performed based on weighted propagation state vectors.

[0033] The time offset relationship is used to characterize the inconsistency in acquisition times at different frequencies caused by polling and receiving. The time offset relationship includes the local time offset between adjacent frequencies and the global offset of each frequency relative to a unified reference time. The process of determining the time offset relationship specifically includes: Read the acquisition times of each frequency point recorded by the time synchronization circuit, and let the number of acquisition times within the current measurement cycle be... frequency points The collection time is The local time offset between adjacent frequency points is denoted as The calculation formula is as follows: ,in Indicates the first frequency points The time of data collection; Indicates the first frequency points The time of data collection; Indicates the first frequency points With the frequency points The time difference between them; Indicates the frequency point number.

[0034] The propagation fingerprint construction module 200 sequentially writes the time difference between each adjacent frequency point into the time offset relationship table; simultaneously, it uses the start time of the current reception and testing cycle... As a unified reference time, the global offset of each frequency point relative to the unified reference time is calculated. The calculation formula is: ,in Indicates the first frequency points The global offset relative to the unified reference time; Indicates the first frequency points The time of data collection; This indicates the start time of the current reception and testing cycle; the local time offset between adjacent frequency points is used to describe the local time difference caused by polling switching, and the global offset of each frequency point relative to the unified reference time is used for subsequent time alignment and time compensation.

[0035] Please see Figure 4 The disturbance correction module 300 extracts synchronization change features from the multi-frequency time-series correlation propagation fingerprint, generates common-mode components based on the synchronization change features, and corrects the received and measured data based on the time offset relationship and the common-mode components to obtain the corrected multi-frequency received and measured results. The synchronization change features are used to represent the change trend of multiple frequency points in a continuous received and measured period, and the common-mode components are used to represent the common disturbance components caused by the vehicle platform's maneuvering behavior.

[0036] The process of extracting synchronous change features specifically includes: First, the propagation state vectors of each frequency point in the multi-frequency time-series correlation propagation fingerprint are time-aligned according to the time offset relationship, so that the propagation state values ​​of different frequencies correspond to a unified reference time. Then, calculate the state change of the propagation state vector for each frequency point in adjacent receiving and measuring cycles; Then, the state changes of multiple frequency points are judged for unidirectionality and amplitude. When multiple frequency points meet the unidirectional change condition and minimum change condition in the same time period, the common change segment is extracted as a synchronous change feature. Synchronous change characteristics are recorded in the form of time period, frequency point group, and change vector group. The time period identifies the measurement period interval in which the synchronous change occurs, the frequency point group identifies multiple frequency points participating in the synchronous change, and the change vector group records the state change vector of each frequency point within that time period. Specifically, the process of calculating the state change amount from the propagation state vector includes: Let the first The frequency point at the first The propagation state vector for each reception cycle is: In the The propagation state vector for each reception cycle is: Then the first The frequency point at the first State change vector corresponding to each monitoring cycle Represented as: ,in Indicates the measurement period number; if ,but ,in: , ,in Indicates the vector dimension index; Indicates the first The frequency point at the first The first of the 1st monitoring period Dimensional parameter values; Indicates the first The frequency point at the first The first of the 1st monitoring period Dimensional parameter values; Indicates the first The frequency point at the first The first of the 1st monitoring period The amount of change in the dimensional parameter.

[0037] The process of determining the directionality specifically includes: For multiple frequency points in the same reception period, determine whether their signs are consistent by analyzing the state change vectors along their respective dimensions; let the number of frequency points participating in the directionality assessment be... For any dimension ,when If all values ​​are positive or all values ​​are negative, then the dimension is determined to meet the condition of changing in the same direction within the measurement period. When at least two of the three dimensions satisfy the condition of changing in the same direction, and the absolute value of each dimension satisfying the condition of changing in the same direction is not less than the minimum change threshold of that dimension. At the same time, it is determined whether multiple frequency points exhibit synchronous change characteristics within the current reception and measurement period; at least two dimensions in the same direction are used for determination to avoid misjudgment caused by occasional fluctuations in a single dimension; among which... to Indicates different frequency points at the 1st The first of the 1st monitoring period The change in dimensional parameters; Indicates the first The minimum change threshold corresponding to the dimension parameter.

[0038] The process of generating common-mode components specifically includes: First, the state change vector in the synchronous change characteristics is aggregated according to its dimension to obtain the common-mode component for the corresponding reception period; the common-mode component is a three-dimensional vector with the same dimension as the propagation state vector; let the number of frequency points participating in the common-mode component calculation in a certain reception period be... The state change vectors at each frequency point are respectively , … Then the first Common-mode components of each monitoring cycle The calculation formula is: ,in Indicates the first The frequency point participating in the common-mode component calculation is at the 1st The state change vector for each measurement cycle; when At that time, the first Common-mode components of each monitoring cycle Set it to the zero vector; the zero vector is a three-dimensional vector with the same dimensions as the corresponding state vector, denoted as . To reduce the impact of abnormal frequency points on common-mode components, the changes in multiple frequency points are first sorted by numerical value in each dimension, the maximum and minimum values ​​are deleted, and then the remaining changes are averaged to obtain the common-mode change value for that dimension.

[0039] The process of generating multi-frequency reception and testing results specifically includes: First, time compensation is performed on the original received data of each frequency point according to the time offset relationship, and the received data of different frequency points is mapped to a unified reference time. After completing time compensation, common mode subtraction is performed. By subtracting the common mode component from the propagation state vector of each frequency point, the correction result of each frequency point after disturbance suppression is obtained. Subsequently, the corrected propagation state vectors of each frequency point are restored to the corrected received signal strength value, corrected group delay value, and corrected multipath spread value according to the correspondence with the original parameters, forming the corrected multi-frequency reception and measurement results. The corrected multi-frequency reception and measurement results characterize the propagation state of each frequency point after eliminating the effects of polling time difference and common disturbances. The time compensation process specifically includes: To unify reference time For the target time, based on the global offset of each frequency point relative to a unified reference time. Perform interpolation mapping on the received data at each frequency point; let the first... Each frequency point at time and time The values ​​of one dimension parameter are respectively and And satisfy Then the target time Corresponding compensation value Calculated using linear interpolation: ,in Indicates a known sampling time that is earlier than the unified reference time; Indicates a known sampling time that is later than the unified reference time; Indicates time The corresponding parameter values; Indicates time The corresponding parameter value; when the denominator The absolute value is less than the interpolation denominator protection threshold. At that time, the compensation value will be directly applied. Set as ;in This represents the interpolation denominator protection threshold, and When the target time is outside the current measurement point, the known parameter value closest to the target time is directly used as the compensation value.

[0040] The common-mode deduction process specifically includes: Let the first The frequency point at the first The propagation state vector after time compensation for each acquisition cycle is: , No. The common-mode components for each reception cycle are Then the first The frequency point at the first Corrected propagation state vector for each measurement cycle Represented as: ; where the corrected propagation state vector After obtaining these values, the corrected received signal strength, corrected group delay, and corrected multipath spread are then restored based on the normalization inverse transform relationship.

[0041] Please see Figure 5 The consistency feature extraction module 400 adjusts the multi-frequency time-series correlation propagation fingerprint based on the corrected multi-frequency reception and measurement results, and extracts path evolution consistency features from the adjusted multi-frequency time-series correlation propagation fingerprint.

[0042] The specific process of writing back the corrected multi-frequency reception and measurement results includes: Read the corrected multi-frequency reception and measurement results, replace the corresponding position data in the original multi-frequency time-series correlation propagation fingerprint with the corrected propagation state vector of each frequency point, and update the time-series trajectory in the propagation fingerprint according to a unified time reference; after the update, the adjusted multi-frequency time-series correlation propagation fingerprint reflects the evolution of the propagation path itself and weakens the common changes caused by vehicle mobility.

[0043] The extraction process of path evolution consistency features specifically includes: For each frequency point, the continuous hold length, the deviation between adjacent receiving / measuring cycles, and the trajectory stability are calculated for the corresponding time-series trajectory. The continuous hold length represents the number of consecutive receiving / measuring cycles in which the propagation state at that frequency point maintains the same effective evolution trend. The deviation between adjacent receiving / measuring cycles represents the magnitude of change in the propagation state at that frequency point between two adjacent receiving / measuring cycles. The trajectory stability represents the degree of concentration of the time-series trajectory at that frequency point relative to the central state. The calculation process for the continuous hold length specifically includes: The direction of change of the corrected propagation state vector at a certain frequency point in multiple consecutive measurement cycles is determined cycle by cycle. When the direction of change of at least two dimensions is consistent in several adjacent measurement cycles, and the corresponding absolute values ​​of change are all within the effective change interval, the continuous segment is defined as a continuous holding segment; the number of measurement cycles covered by the continuous holding segment is the length of the continuous holding segment. The effective change interval is jointly defined by the minimum effective change threshold and the maximum permissible change threshold, and is used to exclude extremely small fluctuations and abnormally severe fluctuations.

[0044] The calculation process for the variation deviation between adjacent measurement cycles specifically includes: Let the first The frequency point at the first The first and second testing period The corrected propagation state vectors for each measurement cycle are as follows: and Then the first The frequency point at the first The first monitoring period is relative to the first Deviation between adjacent monitoring periods in a monitoring period Calculated using Euclidean distance: ,in This represents the Euclidean norm.

[0045] The calculation process for trajectory stability specifically includes: Let the first Each frequency point in continuous The corrected propagation state vectors for each measurement period are as follows: Its central state vector is denoted as Then we have: ,in This indicates the measurement cycle count sequence number in the trajectory stability statistics. When... At that time, the central state vector Set it to the zero vector; further, let the first... The mean dispersion of the trajectory at each frequency point is ,but: ,in, Indicates the first The frequency point at the first The corrected propagation state vector for each reception cycle; when At that time, the first Mean of trajectory dispersion at each frequency point Set to 0; trajectory stability is denoted as and adopt the same as the first Mean of trajectory dispersion at each frequency point The negative correlation is determined in the following ways: ,because Therefore, the denominator When the first Mean of trajectory dispersion at each frequency point When negative values ​​appear in the abnormal data, Set it to 0, and then perform trajectory stability calculation.

[0046] Please see Figure 6 The path determination module 500 determines the validity of the propagation path corresponding to each frequency point based on the consistency characteristics of path evolution, and generates a reliability ranking result; the determination of the validity of the propagation path is based on the following conditions: Condition A: The length of the continuous segment reaches the length threshold; Condition B: The deviation between adjacent measurement cycles does not exceed the deviation threshold; Condition C: The trajectory stability reaches the path stability threshold; The three thresholds are written into the configuration file during system installation and remain unchanged during task execution. The above judgment is performed on each frequency point. If the frequency point meets conditions A, B and C at the same time, the propagation path corresponding to the frequency point is judged as a valid path. If the frequency point does not meet conditions A, B and C at the same time, the propagation path corresponding to the frequency point is judged as an invalid path.

[0047] The process of generating the credibility ranking results specifically includes: First, the length of the continuous holding segment, the deviation of the change between adjacent receiving and receiving cycles, and the trajectory stability are normalized respectively. Then, they are weighted and summed according to fixed weights to obtain the path validity judgment value of each frequency point. Finally, the frequency points are sorted from high to low according to the path validity judgment value to form a credibility ranking result.

[0048] Let the first The length of the continuous hold segment corresponding to each frequency point is The statistical value of the variation deviation between adjacent measurement periods is The trajectory stability is Among them, the statistical value of the variation deviation between adjacent measurement cycles The variation deviation of this frequency point in each adjacent receiving and measuring cycle within the statistical window. The average value is calculated using the following formula: ,in Indicates the first The number of variation deviations between adjacent receiving and measuring cycles for each frequency point; This indicates the count sequence number in the statistical analysis of deviations between adjacent measurement cycles; when At that time, Set to 0.

[0049] Let the minimum and maximum values ​​of the continuous segment length among all frequency points involved in the sorting be respectively... and The minimum and maximum values ​​of the statistical values ​​of the variation deviation between adjacent measurement periods are respectively and The minimum and maximum values ​​of trajectory stability are respectively and Then the first Normalized value of the continuous hold segment length of each frequency point Normalized value of variation deviation between adjacent measurement periods and trajectory stability normalized value Calculate using the following formulas respectively: , , The length of the continuous holding segment is positively normalized; the larger the length of the continuous holding segment, the higher the corresponding normalized value of the continuous holding segment length. The larger the value, the greater the variation deviation between adjacent measurement periods. Inverse normalization is used for the variation deviation between adjacent measurement periods. The smaller the value, the higher the normalized value of the variation deviation between adjacent measurement periods. The larger the value, the greater the trajectory stability; the trajectory stability is obtained by positive normalization. The larger the value, the higher the corresponding trajectory stability normalized value. The larger.

[0050] To prevent the normalization result from being abnormal due to an excessively small denominator, when At that time, the normalized value of the continuous hold length at each frequency point is... Set to 1 uniformly; when At that time, the normalized value of the variation deviation between adjacent receiving and measuring cycles at each frequency point is calculated. Set to 1 uniformly; when At that time, the normalized value of the trajectory stability at each frequency point is... All are set to 1. This represents the sorted normalized denominator protection threshold, and .

[0051] To avoid outliers causing the normalization result to go out of bounds, when At that time, Set to 0, when At that time, Set to 1; when At that time, Set to 0, when At that time, Set to 1; when At that time, Set to 0, when At that time, Set to 1.

[0052] After normalization, let the first... The normalized values ​​of the continuous hold length, the normalized values ​​of the deviation between adjacent reception and measurement cycles, and the normalized values ​​of the trajectory stability for each frequency point are as follows: , and The corresponding weights are respectively , and Then the first Path validity judgment value for each frequency point The calculation formula is: ,in This indicates the scoring weight corresponding to the length of the continuous segment; This indicates the scoring weight corresponding to the variation deviation between adjacent measurement periods; This represents the scoring weight corresponding to trajectory stability; each scoring weight satisfies: .

[0053] If the path validity judgment values ​​of two frequency points are the same, the frequency point with greater trajectory stability is selected first; if the trajectory stability is also the same, the frequency point with a higher polling position in the set frequency point sequence is selected first.

[0054] Please see Figure 7 The result output module 600 determines the target receiving frequency point based on the credibility ranking result and outputs the propagation status judgment result corresponding to the target receiving frequency point; the target receiving frequency point is the frequency point ranked first in the credibility ranking result; the propagation status judgment result is the status identifier corresponding to the target receiving frequency point, and the status identifier includes available status, fluctuating available status and unavailable status.

[0055] The specific process of outputting the propagation state determination result includes: Read the credibility ranking results and determine the target receiving frequency points; Then, obtain the path validity determination result and trajectory stability of the target receiving frequency point; When the target receiving frequency point is determined to be a valid path and the trajectory stability is higher than the state stability threshold, the usable state is output. When the target receiving frequency point is determined to be a valid path and the trajectory stability is not higher than the state stability threshold, the fluctuation usable state is output. When the target receiving frequency point is determined to be an invalid path, an unavailable status is output.

[0056] The result output module 600 synchronously outputs the target receiving frequency, propagation status determination result, credibility ranking result, and path validity determination value for use by the upper-layer shortwave communication strategy module.

[0057] In this embodiment, the normalized denominator protection threshold Interpolation denominator protection threshold And sorting normalized denominator protection threshold All values ​​are positive (greater than 0) to avoid calculation errors caused by excessively small denominators. Their values ​​are determined based on frequency switching accuracy, sampling time resolution, parameter quantization accuracy, and processor numerical computation accuracy; minimum change threshold. The length threshold, deviation threshold, path stability threshold, state stability threshold, minimum effective change threshold, and maximum permissible change threshold are all preset thresholds not less than 0. Specifically, the length threshold is determined based on the requirement for continuous maintenance of the target propagation path; the deviation threshold is determined based on the permissible fluctuation range of the deviation between adjacent measurement cycles; the path stability threshold is determined based on the requirement for determining the effectiveness of the propagation path; the state stability threshold is determined based on the requirement for distinguishing between usable states and fluctuating usable states under an effective path; the minimum effective change threshold is determined based on the requirement for suppressing minor noise disturbances; and the maximum permissible change threshold is determined based on the requirement for excluding abnormally severe fluctuations. The weights of the received signal strength parameters are determined based on the effective variation amplitude of each parameter—received signal strength, group delay, and multipath spread—under maneuvering scenarios. Group delay parameter weights and multipath expansion parameter weights The range of values ​​is And satisfy The scoring weight corresponding to the length of the continuous segment is maintained. The scoring weights corresponding to the deviations between adjacent measurement periods The scoring weights corresponding to trajectory stability The range of values ​​is And satisfy Among them, the weight of the received signal strength parameter Group delay parameter weights and multipath expansion parameter weights The scoring weights corresponding to the length of the continuous hold segment are determined based on the contribution of different parameters to the ability to represent the propagation state. The scoring weights corresponding to the deviations between adjacent measurement periods The scoring weights corresponding to trajectory stability The value of the path validity is determined based on the influence of the continuous holding segment length, the deviation of adjacent measurement cycles, and the trajectory stability. The above thresholds and coefficients are preferably determined by combining the statistical analysis of historical measurement data, the test results of typical maneuver scenarios, and the parameter calibration results during system installation, and remain unchanged during mission execution.

[0058] The overall operation process of this embodiment is as follows: In the process of vehicle-mounted mobile shortwave signal multi-frequency transmission and reception test system, the receiving and receiving data acquisition module 100 first transmits and receives each frequency point in sequence according to a set frequency point sequence, acquires the received signal strength value, group delay value and multipath spread value corresponding to each frequency point, and synchronously records the acquisition time when each frequency point completes acquisition, thereby forming a correspondence between the receiving and receiving data, time sequence and polling order; Subsequently, the propagation fingerprint construction module 200 constructs a multi-frequency time-series associated propagation fingerprint based on the received and tested data, time sequence, and polling order, and determines the local time offset between adjacent frequency points and the global offset of each frequency point relative to a unified reference time. Based on this, the disturbance correction module 300 performs time alignment of the propagation state of each frequency point according to the time offset relationship, extracts the synchronous change characteristics of multiple frequency points in the continuous reception and measurement cycle, generates common mode components that characterize the common disturbance of vehicle-mounted motor, and corrects the reception and measurement data of each frequency point in combination with time compensation to obtain the corrected multi-frequency reception and measurement results. Then, the consistency feature extraction module 400 writes the corrected propagation state back into the multi-frequency time-series associated propagation fingerprint and extracts path evolution consistency features such as the length of the continuous holding segment, the deviation of changes in adjacent receiving and measuring cycles, and the trajectory stability corresponding to each frequency point. Next, the path determination module 500 determines whether the propagation path of each frequency point is effective based on the path evolution consistency characteristics, and generates the path effectiveness determination value and credibility ranking result of each frequency point through normalization and weighted summation. Finally, the result output module 600 determines the target receiving frequency point based on the credibility ranking result, and outputs the corresponding propagation state judgment result by combining the path validity judgment result and trajectory stability of the target receiving frequency point.

[0059] As can be seen from the above description, the vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system provided in this embodiment has the following technical effects: This invention simultaneously retains the reception data, time sequence, and polling order of each frequency point during multi-frequency polling reception and testing, and uniformly writes them into a multi-frequency time-series correlation propagation fingerprint, enabling the propagation state of each frequency point to be analyzed based on time-series correlation. Furthermore, it achieves unified time reference alignment of the propagation states of different frequencies through time offset relationships, and utilizes synchronous change feature extraction and common-mode component subtraction mechanisms to suppress cross-frequency common disturbances caused by vehicle-mounted mobility, thus making the corrected multi-frequency reception and testing results more reflective of the evolution and changes of the propagation path of each frequency point. Based on this, it combines path evolution consistency features such as continuous hold segment length, adjacent reception cycle variation deviation, and trajectory stability to determine the validity and reliability of each frequency point. Therefore, it can reduce the impact of inconsistent polling acquisition times and common disturbances on the determination of target reception frequencies, improving the stability, accuracy, and reference value of target reception frequency selection in vehicle-mounted mobile shortwave multi-frequency reception and testing scenarios.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system, characterized in that, It includes a data acquisition module, a propagation fingerprint construction module, a perturbation correction module, a consistency feature extraction module, a path determination module, and a result output module, among which: The receiving and receiving data acquisition module performs multi-frequency transmission and reception tests on the vehicle platform according to a set frequency point sequence, and acquires the receiving and receiving data corresponding to each frequency point; The propagation fingerprint construction module constructs a multi-frequency time-series associated propagation fingerprint based on the received and tested data, the time sequence corresponding to the received and tested data, and the polling order corresponding to the set frequency point sequence, and determines the time offset relationship. The disturbance correction module extracts synchronization change features from the multi-frequency time-series correlation propagation fingerprint, generates common-mode components based on the synchronization change features, and corrects the received and measured data based on the time offset relationship and the common-mode components to obtain the corrected multi-frequency received and measured results. The consistency feature extraction module adjusts the multi-frequency time-series correlation propagation fingerprint based on the corrected multi-frequency reception and measurement results, and extracts consistency features from the adjusted multi-frequency time-series correlation propagation fingerprint extraction path. The path determination module determines whether the propagation path corresponding to each frequency point is valid based on the path evolution consistency characteristics, and generates a credibility ranking result. The result output module determines the target receiving frequency point based on the credibility ranking result and outputs the propagation state judgment result corresponding to the target receiving frequency point.

2. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The process of acquiring the received data specifically includes: According to the set frequency sequence, the vehicle-mounted transmitter and the vehicle-mounted receiver are controlled to switch frequencies sequentially, so that the vehicle-mounted transmitter transmits shortwave test signals at each frequency and the vehicle-mounted receiver collects propagation response signals in the receiving channel corresponding to each frequency. The vehicle-mounted receiver acquires multiple sampling points within the sampling window corresponding to each frequency point, and performs an average value calculation on the multiple sampling points to obtain the received and measured data for that frequency point; The time synchronization circuit records the corresponding acquisition time when the acquisition is completed at each frequency point, thereby forming the time sequence of the received and measured data. Output the received data for each frequency point, as well as the time sequence corresponding to the received data and the polling order corresponding to the set frequency point sequence; The received data includes received signal strength, group delay, and multipath spread.

3. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The construction process of the multi-frequency temporal correlation propagation fingerprint specifically includes: Arrange the received data at each frequency point within a receiving and testing period according to the time sequence to generate an ordered receiving and testing sequence; Write the polling position of each frequency point in the set frequency point sequence into the ordered receiving and testing sequence, so that each group of receiving and testing data has frequency point identity and polling position information; The received signal strength, group delay, and multipath spread values ​​at each frequency point are normalized, and a propagation state vector is constructed according to a fixed field order. The propagation state vectors of each frequency point are written into the propagation fingerprint structure according to the time order and the polling order to form the multi-frequency time-series associated propagation fingerprint. Each record of the multi-frequency time-series associated propagation fingerprint includes a frequency point identifier, a polling location identifier, a collection time identifier, and a propagation state vector.

4. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The process of determining the time offset relationship specifically includes: Read the acquisition times of each frequency point recorded by the time synchronization circuit; The local time offset between adjacent frequency points is determined based on the acquisition time of adjacent frequency points, and the local time offset between each adjacent frequency point is written into the time offset relationship table in sequence. Using the start time of the current reception and testing cycle as a unified reference time, determine the global offset of each frequency point relative to the unified reference time; The local time offset is used to describe the local time difference caused by polling switching, and the global offset is used for subsequent time alignment and time compensation.

5. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The extraction process of the synchronous change features specifically includes: Based on the time offset relationship, the propagation state vectors of each frequency point in the multi-frequency time-series associated propagation fingerprint are time-aligned so that the propagation state values ​​of different frequency points correspond to a unified reference time. Calculate the state change of the propagation state vector for each frequency point in adjacent reception and measurement cycles; Perform directionality and amplitude judgment on the state changes at multiple frequency points; When multiple frequency points meet the same direction change condition and minimum change condition within the same time period, the common change segment is extracted as the synchronous change feature. The synchronous change characteristics are recorded in the form of time period, frequency point group, and change vector group.

6. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 5, characterized in that, The process of generating the common-mode component specifically includes: The state change vector in the synchronous change feature is aggregated according to its dimension to obtain the common mode component of the corresponding measurement period; The common mode component is a three-dimensional vector with the same dimension as the propagation state vector. In each dimension, the multiple frequency point changes are sorted by numerical value, the maximum and minimum values ​​are removed, and the remaining changes are averaged to obtain the common mode change value for that dimension. When there is no frequency point that participates in the calculation of common-mode components, the common-mode components of the corresponding receiving and measuring period are set to zero vectors; The zero vector is a three-dimensional vector with the same dimension as the corresponding state vector.

7. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The process of generating the multi-frequency reception and measurement results specifically includes: Based on the time offset relationship, time compensation is performed on the original received and measured data of each frequency point, and the received and measured data of different frequency points are mapped to a unified reference time. After completing time compensation, the common-mode component is subtracted from the propagation state vector of each frequency point to obtain the correction result of each frequency point after disturbance suppression. The corrected propagation state vectors at each frequency point are restored to the corrected received signal strength value, corrected group delay value, and corrected multipath spread value according to the correspondence with the original parameters, forming the corrected multi-frequency reception and measurement results; The corrected multi-frequency reception and measurement results characterize the propagation status of each frequency point after eliminating polling time difference and common disturbance effects.

8. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 1, characterized in that, The extraction process of the path evolution consistency feature specifically includes: Read the corrected multi-frequency reception and measurement results, replace the corresponding position data in the original multi-frequency time-series associated propagation fingerprint with the corrected propagation state vector of each frequency point, and update the time-series trajectory in the propagation fingerprint according to a unified time reference. For each frequency point, calculate the length of the continuous hold segment, the deviation between adjacent receiving and receiving cycles, and the trajectory stability of the time-series trajectory. Wherein, the continuous holding segment length represents the number of consecutive reception and measurement cycles in which the propagation state of the frequency point maintains the same effective evolution trend, the adjacent reception and measurement cycle variation deviation represents the variation amplitude of the propagation state of the frequency point between two adjacent reception and measurement cycles, and the trajectory stability represents the degree of concentration of the time sequence trajectory of the frequency point relative to the central state.

9. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 8, characterized in that, The process of generating the credibility ranking results specifically includes: Based on the path evolution consistency characteristics, determine whether the following conditions are met for each frequency point: Condition A: The length of the continuous segment reaches the length threshold; Condition B: The deviation between adjacent measurement cycles does not exceed the deviation threshold; Condition C: The trajectory stability reaches the path stability threshold; If a frequency point simultaneously satisfies conditions A, B, and C, then the propagation path corresponding to that frequency point is determined to be a valid path. If a frequency point does not simultaneously meet conditions A, B, and C, then the propagation path corresponding to that frequency point is determined to be an invalid path. The length of the continuous holding segment, the deviation of the adjacent receiving and measuring cycles, and the trajectory stability are normalized respectively, and then weighted and summed according to fixed weights to obtain the path validity judgment value of each frequency point. The frequency points are sorted from high to low according to the path validity judgment value to form the credibility ranking result.

10. The vehicle-mounted mobile shortwave signal multi-frequency transmission and reception system according to claim 9, characterized in that, The specific process for outputting the propagation state determination result includes: Read the credibility ranking results and determine the target receiving frequency point; Obtain the path validity determination result and trajectory stability of the target receiving and receiving frequency point; When the target receiving frequency point is determined to be a valid path and the trajectory stability is higher than the state stability threshold, the available state is output. When the target receiving frequency point is determined to be a valid path and the trajectory stability is not higher than the state stability threshold, the fluctuation usable state is output. When the target receiving frequency point is determined to be an invalid path, an unavailable status is output. Output the target receiving frequency, the propagation status determination result, the credibility ranking result, and the path validity determination value.

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