Satellite mobile terminal positioning optimization method based on multi-source data analysis

Abstract

The present application relates to satellite navigation and communication technology field, especially to a kind of satellite mobile terminal positioning optimization method based on multi-source data analysis.The present application is by collecting the acceleration data of terminal, determines that terminal is stationary and initiates ranging to other terminals in group, stores the ranging value as rigid baseline set;Get current ranging value, and compare with the corresponding initial value in rigid baseline set, calculate the baseline length change quantity, when baseline change quantity exceeds pre-set threshold, the difference between the acceleration data of two terminals is greater than difference threshold, then record the current ranging value effective;Acceleration difference is not greater than difference threshold and change quantity continues to exceed threshold, then record as invalid and eliminate;Effective ranging value and inertial navigation system calculated position are jointly solved, and the positioning result is output;When the distance value of terminal and other terminals in group is continuously monotone increasing and the increment is all greater than pre-set increment threshold, determine that the terminal is out of group, switch to output azimuth angle information and distance change rate information.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation and communication technology. In particular, it relates to a satellite mobile terminal positioning optimization method based on multi-source data analysis. Background Technology

[0002] Currently, satellite mobile terminals are susceptible to non-line-of-sight interference in scenarios such as urban canyons, vegetation obstruction, field formations, and emergency operations, leading to ranging jumps and positioning drift. Inertial navigation also suffers from error accumulation issues over long periods of calculation. Traditional cooperative positioning schemes struggle to distinguish between normal group formation adjustments and ranging anomalies caused by environmental interference. When a terminal leaves the group and absolute positioning fails, the group cannot continuously acquire the terminal's location information.

[0003] Chinese Patent Application Publication No. CN111273687A discloses a multi-UAV cooperative relative navigation method based on GNSS observations and inter-UAV ranging. This method involves acquiring GNSS observations by collecting and tracking satellite signals using GNSS receivers on each UAV, and obtaining inter-UAV relative distance information through a relative ranging module. The inter-UAV communication module broadcasts and aggregates navigation information from each UAV, using the inter-UAV relative distance information to assist in GNSS relative differential estimation of the baseline between UAVs. Using one UAV as a reference, the relative position vector is used to obtain the position of each UAV relative to the reference, and this is integrated with the GNSS observations to form relative navigation information. Another UAV is selected outside the reference, and the relative navigation information related to that UAV and the reference in the UAV formation is used to solve for the position of that UAV relative to the reference, optimizing the original baseline solution. Using the existing baseline solutions and measurements, the baseline solutions with lower accuracy are optimized sequentially until all baseline solutions in the formation converge, completing the multi-UAV cooperative relative navigation.

[0004] Therefore, the multi-UAV cooperative relative navigation method based on GNSS observations and inter-UAV ranging has the following problems: it lacks consistency judgment of terminal motion state, is prone to misjudging non-line-of-sight ranging as valid measurement, and has no terminal separation recognition and degradation output, resulting in insufficient navigation continuity and reliability. Summary of the Invention

[0005] To address these issues, this invention provides a satellite mobile terminal positioning optimization method based on multi-source data analysis. This method overcomes the problems in existing technologies, such as the lack of consistency in judging the terminal's motion state, the tendency to misjudge non-line-of-sight ranging as valid measurements, the absence of terminal disconnection identification and degraded output, and insufficient navigation continuity and reliability.

[0006] To achieve the above objectives, this invention provides a satellite mobile terminal positioning optimization method based on multi-source data analysis. The method includes: Acceleration data of each terminal in the assembly group is collected in response to the determination that the terminal is stationary, and ranging is initiated to other terminals in the group. The initial ranging values ​​returned by each other terminal are recorded and stored as several rigid baseline values ​​to determine the initial relative spatial relationship between the terminal and other terminals in the group, as well as between the other terminals. During the journey, the current ranging values ​​of the terminal and other terminals in the group are periodically acquired, and the length change of each baseline is determined based on the comparison results between the current ranging values ​​and the rigid baseline values. In response to any of the aforementioned length changes exceeding a preset change threshold, a sudden change in the baseline length is determined. The cause of the sudden change is determined based on the difference in acceleration data between the two corresponding terminals, and the validity of the corresponding current ranging value is determined based on the cause of the sudden change. Based on the time change trend of the effective current ranging value of each terminal, it is determined whether the relationship between each terminal and other terminals in the group is increasing, and based on the increase rate, it is determined whether the terminal has left the group. In response to the terminal not leaving the group, all valid current ranging values ​​are jointly calculated with the position estimated by the inertial navigation system to output the optimized positioning result at the current moment; in response to the terminal leaving the group, the output of absolute position coordinates is stopped, and the output of the azimuth angle information and distance change rate information of the terminal relative to the geometric center of the group is switched to output.

[0007] Furthermore, the process of collecting acceleration data from each terminal within the assembly group, and in response to determining that the terminal is stationary, initiating ranging to other terminals within the group, recording the initial ranging values ​​returned by each of the other terminals, and storing them as several rigid baseline values ​​includes: Collect continuous acceleration data from the terminal within a preset collection time. Determine whether the terminal is stationary based on the continuous acceleration data; In response to determining that the terminal is in a stationary state, the system initiates ranging requests to other terminals in the group and receives the initial ranging values ​​returned by each other terminal. The initial ranging values ​​are established in a one-to-one correspondence with the corresponding terminal identifiers and stored as the rigid baseline values.

[0008] Furthermore, the process of determining the variation in the length of each baseline includes: Obtain the current ranging value between the terminal and other terminals in the group during the current ranging period; Match the rigid baseline value corresponding to each current ranging value; Calculate the distance difference between each current distance measurement value and the corresponding rigid baseline value; The length change of the corresponding baseline is determined based on the distance difference.

[0009] Furthermore, the process of determining the cause of the abrupt change based on the difference in acceleration data between the two corresponding terminals includes: Acquire acceleration data for the corresponding time periods of the two terminals where baseline length abruptly changes; Determine the motion status of the two terminals within the corresponding time period; Determine whether the sudden change in baseline length is caused by relative motion of the terminals based on whether there is a difference between the motion states of the two terminals; If there is no difference in the motion states of the two terminals, it is determined that the sudden change in the baseline length is caused by abnormal ranging.

[0010] Furthermore, the process of determining whether the current ranging value is valid based on the cause of the mutation includes: In response to determining that the baseline length abrupt change is caused by relative motion of the terminal, the corresponding current ranging value is retained; In response to the determination that the baseline length abrupt change is caused by abnormal ranging, the corresponding current ranging value is discarded; The retained current distance value is used as the valid current distance value.

[0011] Furthermore, the process of determining whether there is an increasing change between each terminal and other terminals within the group includes: Obtain the valid current ranging value corresponding to multiple consecutive ranging cycles; Generate the effective ranging change sequence for each terminal respectively; Determine the direction of distance change based on each effective distance measurement change sequence; When the direction of the corresponding distance change continuously points away from the group, it is determined that the distance between the terminal and the group is increasing.

[0012] Furthermore, the process of determining whether a terminal has left the group based on the increment magnitude includes: Determine the corresponding distance increment between the terminal and each other terminal in the group; Count the number of terminals that meet the requirement of continuously increasing distance; When the distance increments are all greater than a preset increment threshold and the number of terminals whose distances are continuously increasing reaches the number of terminals in the group, it is determined that the terminal has left the group.

[0013] Furthermore, the process of jointly calculating the position by combining all valid current ranging values ​​with the position calculated by the inertial navigation system includes: Obtain the current position calculated by the inertial navigation system; Establish spatial distance constraints between terminals based on all valid current ranging values; The current position is corrected using the spatial distance constraint; Output the corrected and optimized positioning results.

[0014] Furthermore, the process of determining the geometric center of the group includes: Obtain location results for users within the group who are still on the device; Determine the geometric center of the group based on the position of each terminal that has not detached from the terminal; The geometric center of the group is used as the relative positioning reference point for the device detached from the terminal.

[0015] Furthermore, the process of outputting the azimuth information and distance change rate information of the terminal relative to the geometric center of the group includes: Determine the relative positional relationship between the detached terminal and the geometric center of the group; Calculate the azimuth information based on the relative positional relationship; The distance change rate information is determined based on the change in the relative positional relationship over multiple consecutive ranging cycles; Output the azimuth information and distance change rate information.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention establishes a rigid baseline value between terminals within a disaster relief team during the assembly phase, making the initial relative spatial relationship within the team a stable reference for subsequent positioning. Subsequently, during the team's movement, it identifies abrupt changes in baseline length by analyzing the relationship between the current ranging value and the rigid baseline value, and further analyzes the causes of these changes by combining the acceleration data differences of the corresponding terminals. This distinguishes between actual distance changes caused by formation adjustments and abnormal ranging changes caused by complex field environments, preventing abnormal ranging from participating in positioning calculations. Furthermore, based on the filtered effective ranging values, it continuously analyzes the distance change trends between terminals within the team, promptly identifies terminals out of the team, and switches positioning output modes for different team states. This allows terminals to obtain more stable and optimized positioning results while maintaining team coordination, and to still output relative azimuth information and distance change rate information with rescue guidance value even after leaving the team. Therefore, this invention fully utilizes the inherent group behavior patterns during the disaster relief team's movement as positioning constraints, effectively reducing the impact of abnormal ranging on positioning results in complex field environments, and improving the positioning reliability and rescue support capabilities of satellite mobile terminals in disaster relief coordination scenarios. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the satellite mobile terminal positioning optimization method based on multi-source data analysis as described in this invention. Figure 2 This is a logic diagram for determining whether the terminal is in a stationary state in this embodiment; Figure 3 This is a logic diagram for determining whether there is an incremental change between each terminal and other terminals in the group in this embodiment; Figure 4 This is a logic diagram for determining whether a terminal has left the group based on the incrementing magnitude in this embodiment. Detailed Implementation

[0018] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0019] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] Please see Figure 1 As shown, this is a flowchart illustrating the satellite mobile terminal positioning optimization method based on multi-source data analysis according to the present invention. The method in this embodiment includes: S10. Collect acceleration data of each terminal in the assembly group, and in response to determining that the terminal is stationary, initiate ranging to other terminals in the group, record the initial ranging values ​​returned by each other terminal and store them as several rigid baseline values, so as to determine the initial relative spatial relationship between the terminal and other terminals in the group and between each other terminal. S20. During the journey, periodically acquire the current ranging values ​​of the terminal and other terminals in the group, and determine the length change of each baseline based on the comparison result between the current ranging value and the rigid baseline value. S30. In response to any of the length changes exceeding a preset change threshold, a sudden change in the baseline length is determined. The cause of the sudden change is determined based on the difference in acceleration data between the two corresponding terminals. Based on the cause of the sudden change, it is determined whether the corresponding current ranging value is valid. The preset change threshold is a benchmark for determining whether the current ranging value has undergone an abnormal change beyond the normal ranging fluctuation range relative to the corresponding rigid baseline value. It is determined based on the ranging fluctuation range measured by the corresponding terminal within multiple consecutive ranging cycles under static conditions at the assembly point, thus defining the allowable distance variation range for the corresponding terminal under normal ranging conditions. The larger the ranging fluctuation range, the larger the preset change threshold; the smaller the ranging fluctuation range, the smaller the preset change threshold. S40. Based on the time change trend of the effective current ranging value of each terminal, determine whether there is an increasing change between each terminal and other terminals in the group, and determine whether the terminal has left the group based on the increase rate. S50. In response to the terminal not leaving the group, all valid current ranging values ​​and the calculated position of the inertial navigation system are jointly calculated to output the optimized positioning result at the current moment; in response to the terminal leaving the group, the output of absolute position coordinates is stopped, and the output of the azimuth angle information and distance change rate information of the terminal relative to the geometric center of the group is switched to output.

[0021] Specifically, this invention establishes a rigid baseline value between terminals within a disaster relief team during the team's assembly phase, using the initial relative spatial relationship within the team as a stable reference for subsequent positioning. Subsequently, during the team's movement, it identifies abrupt changes in baseline length by analyzing the relationship between the current ranging value and the rigid baseline value, and further analyzes the causes of these changes by combining the acceleration data differences of the corresponding terminals. This distinguishes between actual distance changes caused by formation adjustments and abnormal ranging changes caused by complex field environments, preventing abnormal ranging from participating in positioning calculations. Furthermore, based on the filtered effective ranging values, it continuously analyzes the distance change trends between terminals within the team, promptly identifying terminals out of the team and switching positioning output modes according to different team states. This allows terminals to obtain more stable and optimized positioning results while maintaining team coordination, and to still output relative azimuth information and distance change rate information with rescue guidance value even after leaving the team. Therefore, this invention fully utilizes the inherent group behavior patterns during the disaster relief team's movement as positioning constraints, effectively reducing the impact of abnormal ranging on positioning results in complex field environments, and improving the positioning reliability and rescue support capabilities of satellite mobile terminals in disaster relief coordination scenarios.

[0022] Please see Figure 2 As shown, this is the logic diagram for determining whether the terminal is in a stationary state in this embodiment. In this embodiment, the process of storing the rigid baseline value includes: The system acquires triaxial acceleration data output from the terminal's built-in inertial measurement unit and continuously collects acceleration data corresponding to each sampling moment within a preset acquisition time to collect the continuous acceleration data. The preset acquisition time is the continuous monitoring time that covers the natural static fluctuation process of the terminal. It is determined based on the duration of the influence of the natural swing of the human body on the acceleration change when the terminal is stationary, so that the continuous acceleration data collected within the preset acquisition time can cover the acceleration fluctuations caused by the natural swing of the human body. The longer the duration of the natural swing of the human body, the longer the preset acquisition time is set; the shorter the duration of the natural swing of the human body, the shorter the preset acquisition time is set. The acceleration change between sampling times is determined based on the triaxial acceleration data collected continuously at each sampling time, and it is then determined whether the acceleration change remains within the normal static fluctuation range. If the acceleration change remains within the normal static fluctuation range, the terminal is determined to be in a static state; otherwise, the terminal is determined not to be in a static state. The normal static fluctuation range is the normal variation range of continuous acceleration data formed in a static state within a preset collection time. It is determined based on the acceleration data continuously collected when the terminal is stationary, in order to distinguish between normal acceleration changes caused by natural micro-movements of the human body and acceleration changes caused by actual movement of the terminal. The larger the normal static fluctuation range, the higher the tolerance of the static determination to short-term acceleration fluctuations; the smaller the normal static fluctuation range, the more sensitive the static determination to acceleration changes. In response to determining that the terminal is in a stationary state, the control terminal sends a ranging request to each other terminal in the group through a short-range wireless ranging module. After receiving the ranging request, each other terminal returns the corresponding ranging response information. The terminal obtains the initial ranging value between itself and each other terminal based on the ranging response information. Obtain the terminal identification information corresponding to each other terminal, associate each terminal identification information with the corresponding initial ranging value to form the initial distance relationship between each terminal, and store the rigid baseline value by establishing an index relationship according to the terminal identification information.

[0023] In this embodiment, the process of determining the length change of each baseline includes: obtaining the current ranging value between the terminal and other terminals in the group within the current ranging period; matching the rigid baseline value corresponding to each current ranging value; calculating the distance difference between each current ranging value and the corresponding rigid baseline value; and determining the length change of the corresponding baseline based on the distance difference.

[0024] Specifically, in determining the change in the length of each baseline, this embodiment of the invention sequentially obtains the current ranging values ​​between the terminal and other terminals in the group within the current ranging period, and matches the rigid baseline values ​​corresponding to each current ranging value to correspond the real-time ranging results with the initial relative spatial relationship established in the static state of the assembly point. Based on this, the distance difference between each current ranging value and the corresponding rigid baseline value is calculated, and the length change of the corresponding baseline is determined according to the distance difference to quantify the deviation of the real-time ranging relative to the initial reference into a comparable value. The obtained length change is used as a direct input for subsequent judgment to compare with a preset change threshold to identify whether the baseline length has changed abruptly, thereby supporting the judgment of the validity of the current ranging value and ensuring that the ranging data on which the subsequent positioning calculation is based is true and valid.

[0025] In this embodiment, the process of determining the cause of the abrupt change based on the difference in acceleration data of the two corresponding terminals includes: acquiring acceleration data of the two terminals that experienced the baseline length abrupt change within the corresponding time period; determining the motion state of the two terminals within the corresponding time period; determining whether the baseline length abrupt change is caused by the relative motion of the terminals based on whether there is a difference between the motion states of the two terminals; and determining that the baseline length abrupt change is caused by abnormal ranging in response to the absence of a difference between the motion states of the two terminals.

[0026] Specifically, in this embodiment, the process of determining the cause of the abrupt change based on the difference in acceleration data between the two terminals includes the following steps: First, the acceleration data of the two terminals that experienced the baseline length abrupt change are acquired within the corresponding time period, and the two sets of acceleration data are aligned on the time axis to ensure that the subsequent comparative analysis is based on the same time reference; then, the acceleration signals of the two terminals are filtered and denoised, and the gravity component is separated to extract the linear acceleration that reflects the actual motion of the terminals. Then, statistical quantities such as root mean square and standard deviation of acceleration are extracted from the time domain, and features such as the main frequency energy distribution and fluctuation law are extracted from the frequency domain to quantify the motion intensity and motion pattern of each terminal within the corresponding time period; then, the motion state of each terminal is classified into categories such as stationary, slight movement, regular movement, or violent irregular movement according to the extracted features, and the motion states of the two terminals are compared to see if there are significant differences; if the motion states of the two terminals are consistent or highly similar, it indicates that there is no relative displacement between them, and the baseline length abrupt change is determined to be caused by abnormal ranging rather than relative motion between the terminals; conversely, if there are significant differences in the motion states of the two terminals, it indicates that there is relative displacement between the terminals, and the baseline length abrupt change is determined to be caused by the natural relative motion of the terminals.

[0027] Specifically, through the objective comparative analysis of acceleration data from both terminals, the embodiments of the present invention achieve accurate attribution of the cause of sudden changes in baseline length, effectively distinguish between equipment ranging anomalies and environmental motion factors, avoid misjudging baseline changes caused by the terminal's own motion as equipment failure, and significantly improve the accuracy and robustness of ranging anomaly determination.

[0028] Based on the above embodiments, the process of determining whether the current ranging value is valid based on the cause of the mutation includes: in response to determining that the baseline length mutation is caused by the relative motion of the terminal, retaining the corresponding current ranging value; In response to the determination that the baseline length abrupt change is caused by abnormal ranging, the corresponding current ranging value is discarded; the retained current ranging value is taken as the valid current ranging value.

[0029] Specifically, in this embodiment, the process of determining the validity of the current ranging value based on the cause of the mutation is as follows: First, the determination result of the cause of the baseline length mutation is obtained to distinguish whether the mutation is caused by the relative motion between the two terminals or by the abnormal ranging of the ranging device itself; then, the validity of the ranging value is judged according to the determination result. If the baseline length mutation is determined to be caused by the relative motion of the terminals, it indicates that the ranging value reflects the actual physical distance change between the terminals, so the corresponding current ranging value is retained and used as a valid current ranging value. If the baseline length mutation is determined to be caused by abnormal ranging, it indicates that the ranging value is not caused by the actual position change between the terminals but by the error of the ranging system itself, so the corresponding current ranging value is invalid data and is removed; finally, the current ranging value retained after the above screening is output as a valid current ranging value for subsequent positioning or distance monitoring.

[0030] Specifically, the embodiments of the present invention achieve real-time identification and elimination of abnormal ranging values ​​by filtering the ranging values ​​based on the determination of the cause of mutation. At the same time, the true ranging changes caused by the actual movement of the terminal are retained. This not only avoids the pollution of positioning accuracy and distance monitoring reliability by abnormal data, but also ensures the complete retention of effective ranging information, which significantly improves the data quality and robustness of the ranging system in dynamic environments.

[0031] Please see Figure 3 As shown, this is a logic diagram for determining whether there is an increasing change between each terminal and other terminals in the group in this embodiment. In this embodiment, the process of determining whether there is an increasing change between each terminal and other terminals in the group includes: Obtain valid current ranging values ​​corresponding to multiple consecutive ranging cycles; wherein, the valid current ranging values ​​are the ranging data retained after determining the cause of the mutation and filtering the validity, representing the real distance information between each terminal and other terminals in the group.

[0032] Each terminal generates a valid ranging change sequence; the direction of distance change is determined based on each valid ranging change sequence; when the direction of distance change continuously points away from the group, it is determined that the distance between the terminal and the group is increasing. Each valid ranging change sequence is formed by arranging the valid ranging values ​​between the same terminal and other terminals in the group in chronological order over multiple consecutive ranging periods, representing the trend of distance change between the terminal and the group over time.

[0033] In this embodiment of the invention, the process of determining whether there is an increasing change in distance between each terminal and other terminals in the group is as follows: First, obtain the valid current distance measurement value corresponding to multiple consecutive distance measurement cycles. Then, generate the valid distance change sequence corresponding to each terminal. Next, determine the corresponding distance change direction based on each valid distance change sequence. That is, by analyzing the change law of distance value increasing or decreasing with distance measurement cycle in the valid distance change sequence, determine whether each terminal is approaching or moving away from the group. Finally, when the corresponding distance change direction points away from the group for multiple consecutive distance measurement cycles, it is determined that there is an increasing change between the terminal and the group.

[0034] Specifically, the embodiments of the present invention construct a continuous multi-period effective ranging change sequence and determine the trend of its change direction, thereby achieving accurate identification of the distance change direction between the terminal and the group. This avoids interference from single ranging anomalies or occasional fluctuations on the determination results, ensures the continuity and reliability of incremental change determination, and provides stable and accurate data support for subsequent decision-making based on the group distance change trend.

[0035] Please see Figure 4 The diagram shown illustrates the logic for determining whether a terminal has left the group based on the incrementing distance in this embodiment. In this embodiment, the process of determining whether a terminal has left the group based on the incrementing distance includes: determining the distance increment between the terminal and other terminals in the group; counting the number of terminals that satisfy the condition of continuously increasing distance; and determining that the terminal has left the group when all distance increments are greater than a preset increment threshold and the number of terminals satisfying the condition of continuously increasing distance reaches the group's terminal count. The preset incremental threshold is a benchmark value used to determine whether the distance between the terminal and any other terminal in the group has effectively increased. It is determined based on the range of distance change fluctuations measured by the corresponding terminal in a relatively static or stable formation state within multiple consecutive ranging cycles, in order to eliminate the interference of minor distance fluctuations caused by ranging noise, signal jitter, or environmental interference on the departure determination. The preset incremental threshold is set to be greater than the upper limit of the above fluctuation range. The larger the range of distance change fluctuations, the larger the preset incremental threshold is set; the smaller the range of distance change fluctuations, the smaller the preset incremental threshold is set.

[0036] Specifically, in this embodiment of the invention, the process of determining whether a terminal has left the group based on the incremental increase is as follows: First, based on the determination that the distance between the terminal and the group is increasing, the effective current distance measurement value between the terminal and each other terminal in the group is obtained within multiple consecutive distance measurement periods, and the distance increment corresponding to each other terminal is calculated. The distance increment quantifies the specific magnitude of the increase in distance between the terminal and each other terminal within the corresponding time interval. Then, for each other terminal in the group, it is determined whether the distance corresponding to it is continuously increasing within multiple consecutive distance measurement periods, and the number of terminals that meet the condition of continuous distance increase is counted. Then, each distance increment is compared with a preset increment threshold, and it is determined whether the number of terminals that meet the condition of continuous distance increase reaches the total number of terminals in the group. When the distance increments are all greater than the preset increment threshold and the number of terminals that meet the condition of continuous distance increase reaches the total number of terminals in the group, it indicates that the distance between the terminal and all other terminals in the group has increased significantly and continuously, and the terminal is determined to have left the group.

[0037] Specifically, in determining whether a terminal has left the group, this embodiment of the invention first determines the distance increment between the terminal and other terminals in the group. This quantifies the deviation of the effective ranging value from the rigid baseline value into a comparable value, providing a data basis for the departure determination. Then, it counts the number of terminals that meet the condition of continuously increasing distance, introducing a global perspective of the group to avoid misjudgments caused by changes in distance between a single terminal, ensuring that the determination is based on a comprehensive analysis of the trends of changes in each baseline. Finally, when the distance increments are all greater than a preset increment threshold and the number of terminals that meet the condition of continuously increasing distance reaches the number of terminals in the group, the terminal is determined to have left the group. At the same time, this embodiment of the invention achieves accurate identification and highly robust determination of departure behavior by requiring a significant increase in distance and a continuous increase in distance from all terminals. This provides a reliable trigger basis for timely switching of the subsequent positioning output mode, thereby ensuring that the positioning optimization strategy can effectively adapt and operate in different group states.

[0038] In this embodiment, the process of jointly solving all valid current ranging values ​​and the position calculated by the inertial navigation system includes: obtaining the current position calculated by the inertial navigation system; establishing spatial distance constraints between terminals based on all valid current ranging values; correcting the current position using the spatial distance constraints; and outputting the corrected optimized positioning result.

[0039] Specifically, in this embodiment of the invention, the process of jointly solving all valid current ranging values ​​and the position calculated by the inertial navigation system is as follows: First, the current position of the current terminal calculated by the inertial navigation system is obtained. The current position is an estimated value recursively obtained by the inertial navigation system based on the position and motion sensor data of the previous moment, which has accumulated errors as the running time increases. Then, spatial distance constraints between terminals are established based on all valid current ranging values. That is, using each valid ranging value retained after the determination of the cause of mutation and the validity screening, a geometric distance equation between the current terminal and each other terminal in the group is constructed as a rigid measure of the relative spatial relationship between terminals. Then, the current position is corrected using the spatial distance constraints. That is, the real distance information represented by the above valid ranging values ​​is used as the observation value to correct the position estimate calculated by the inertial navigation system. Finally, the corrected optimized positioning result is output.

[0040] Specifically, this embodiment of the invention introduces the effective distance information between terminals within a group obtained by the ranging system as an external constraint into the inertial navigation calculation process. It makes full use of the high-precision absolute distance characteristics of the ranging value and the continuous calculation capability of the inertial navigation system, effectively suppressing the problem of the positioning accuracy of the inertial navigation system decreasing over time due to integral drift and cumulative error. This significantly improves the positioning accuracy and robustness of the terminal in complex dynamic environments, providing reliable and stable technical support for terminal positioning based on group cooperation.

[0041] In this embodiment, the process of determining the geometric center of the group includes: obtaining the positioning results of those within the group who have not left the terminal; determining the geometric center of the group based on the position of each of those who have not left the terminal; and using the geometric center of the group as a relative positioning reference point for those who have left the terminal.

[0042] Specifically, in this embodiment of the invention, the process of determining the geometric center of the group is as follows: First, the positioning results of the terminals that have not yet left the group are obtained. These terminals are those confirmed to still belong to the group after incremental increment determination. Their positioning results can be obtained through inertial navigation joint calculation or satellite positioning, serving as effective reference points for determining the overall spatial distribution of the group. Then, the geometric center of the group is determined based on the positions of each terminal that has not yet left the group. That is, the arithmetic mean or weighted average position of the spatial coordinates of all terminals that have not yet left the group is used to characterize the overall center position of the group. Finally, the geometric center of the group is used as a relative positioning reference point for terminals that have left the group. When a terminal leaves the group, this geometric center replaces the original group reference benchmark, providing a new relative positioning benchmark for the departing terminal. This invention dynamically calculates the geometric center of the group using the reliable positioning results of terminals that have not yet left the group and uses it as a relative positioning reference point for departing terminals. This achieves adaptive updating of the reference benchmark when some terminals leave the group, avoiding positioning failure caused by the loss of effective reference within the group due to departing terminals. It ensures that departing terminals can still obtain effective relative positioning benchmarks after leaving the group, significantly improving the adaptability and continuity of the group positioning system in dynamically changing scenarios.

[0043] Specifically, in determining the geometric center of a group, this embodiment of the invention first obtains the positioning results of the terminals that have not yet left the group to obtain the spatial location information of the effective terminals in the current group; then, it determines the geometric center of the group based on the position of each terminal that has not yet left the group, so as to recalculate the center position of the group after removing the terminals that have left the group; on this basis, the geometric center of the group is used as the relative positioning reference point of the terminals that have left the group to replace the original absolute coordinate output, so as to provide the terminals that have left the group with information on the change in orientation and distance relative to the group, so as to provide effective rescue guidance even when they have left the group.

[0044] In this embodiment, the process of outputting the azimuth information and distance change rate information of the terminal relative to the geometric center of the group includes: determining the relative positional relationship between the detached terminal and the geometric center of the group; calculating the azimuth information based on the relative positional relationship; determining the distance change rate information based on the change of the relative positional relationship within multiple consecutive ranging cycles; and outputting the azimuth information and distance change rate information.

[0045] Specifically, in this embodiment of the invention, when outputting azimuth and distance change rate information, the relative positional relationship between the detached terminal and the geometric center of the group is first determined to obtain spatial difference data between the two at the current moment; then, azimuth information is calculated based on the relative positional relationship to convert the spatial difference into guidance relative to the group direction; simultaneously, distance change rate information is determined based on the change of the relative positional relationship over multiple consecutive ranging cycles to reflect the movement trend of the detached terminal relative to the group; finally, the azimuth and distance change rate information are output, thereby providing the terminal with orientation and dynamic change information relative to the group in the detached state, ensuring the continuous effectiveness of rescue guidance.

[0046] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A satellite mobile terminal positioning optimization method based on multi-source data analysis, characterized in that, include: Acceleration data of each terminal in the assembly group is collected in response to the determination that the terminal is stationary, and ranging is initiated to other terminals in the group. The initial ranging values ​​returned by each other terminal are recorded and stored as several rigid baseline values ​​to determine the initial relative spatial relationship between the terminal and other terminals in the group, as well as between the other terminals. During the journey, the current ranging values ​​of the terminal and other terminals in the group are periodically acquired, and the length change of each baseline is determined based on the comparison results between the current ranging values ​​and the rigid baseline values. In response to any of the aforementioned length changes exceeding a preset change threshold, a sudden change in the baseline length is determined. The cause of the sudden change is determined based on the difference in acceleration data between the two corresponding terminals, and the validity of the corresponding current ranging value is determined based on the cause of the sudden change. Based on the time change trend of the effective current ranging value of each terminal, it is determined whether the relationship between each terminal and other terminals in the group is increasing, and based on the increase rate, it is determined whether the terminal has left the group. In response to the terminal not leaving the group, all valid current ranging values ​​are jointly calculated with the position estimated by the inertial navigation system to output the optimized positioning result at the current moment; in response to the terminal leaving the group, the output of absolute position coordinates is stopped, and the output of the azimuth angle information and distance change rate information of the terminal relative to the geometric center of the group is switched to output.

2. The optimization method according to claim 1, characterized in that, The process of collecting acceleration data from each terminal within the assembly group, and in response to determining that a terminal is stationary, initiating ranging to other terminals within the group, recording the initial ranging values ​​returned by each of the other terminals, and storing them as several rigid baseline values ​​includes: Collect continuous acceleration data from the terminal within a preset collection time. Determine whether the terminal is stationary based on the continuous acceleration data; In response to determining that the terminal is in a stationary state, the system initiates ranging requests to other terminals in the group and receives the initial ranging values ​​returned by each other terminal. The initial ranging values ​​are established in a one-to-one correspondence with the corresponding terminal identifiers and stored as the rigid baseline values.

3. The optimization method according to claim 1, characterized in that, The process of determining the change in length of each baseline includes: Obtain the current ranging value between the terminal and other terminals in the group during the current ranging period; Match the rigid baseline value corresponding to each current ranging value; Calculate the distance difference between each current distance measurement value and the corresponding rigid baseline value; The length change of the corresponding baseline is determined based on the distance difference.

4. The optimization method according to claim 1, characterized in that, The process of determining the cause of the sudden change based on the difference in acceleration data between the two corresponding terminals includes: Acquire acceleration data for the corresponding time periods of the two terminals where baseline length abruptly changes; Determine the motion status of the two terminals within the corresponding time period; Determine whether the sudden change in baseline length is caused by relative motion of the terminals based on whether there is a difference between the motion states of the two terminals; If there is no difference in the motion states of the two terminals, it is determined that the sudden change in the baseline length is caused by abnormal ranging.

5. The optimization method according to claim 4, characterized in that, The process of determining whether the current ranging value is valid based on the cause of the mutation includes: In response to determining that the baseline length abrupt change is caused by relative motion of the terminal, the corresponding current ranging value is retained; In response to the determination that the baseline length abrupt change is caused by abnormal ranging, the corresponding current ranging value is discarded; The retained current distance value is used as the valid current distance value.

6. The optimization method according to claim 1, characterized in that, The process of determining whether there is an increasing change between each terminal and other terminals in the group includes: Obtain the valid current ranging value corresponding to multiple consecutive ranging cycles; Generate the effective ranging change sequence for each terminal respectively; Determine the direction of distance change based on each effective distance measurement change sequence; When the direction of the corresponding distance change continuously points away from the group, it is determined that the distance between the terminal and the group is increasing.

7. The optimization method according to claim 6, characterized in that, The process of determining whether a terminal has left the group based on the increment magnitude includes: Determine the corresponding distance increment between the terminal and each other terminal in the group; Count the number of terminals that meet the condition of continuously increasing distance; When the distance increments are all greater than a preset increment threshold and the number of terminals whose distances are continuously increasing reaches the number of terminals in the group, it is determined that the terminal has left the group.

8. The optimization method according to claim 1, characterized in that, The process of jointly calculating the position by combining all valid current ranging values ​​with the position calculated by the inertial navigation system includes: Obtain the current position calculated by the inertial navigation system; Establish spatial distance constraints between terminals based on all valid current ranging values; The current position is corrected using the spatial distance constraint; Output the corrected and optimized positioning results.

9. The optimization method according to claim 1, characterized in that, The process of determining the geometric center of the group includes: Obtain location results for users within the group who are still on the device; Determine the geometric center of the group based on the position of each terminal that has not detached from the terminal; The geometric center of the group is used as the relative positioning reference point for the device detached from the terminal.

10. The optimization method according to claim 1, characterized in that, The process of outputting the azimuth information and distance change rate information of the terminal relative to the geometric center of the group includes: Determine the relative positional relationship between the detached terminal and the geometric center of the group; Calculate the azimuth information based on the relative positional relationship; The distance change rate information is determined based on the changes in the relative positional relationship over multiple consecutive ranging cycles; Output the azimuth information and distance change rate information.

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