CN-121995311-A - Grid exhaustive search cross-pulse pairing method based on correlation matching

Abstract

The invention discloses a grid exhaustive search cross-pulse pairing method based on correlation matching, and belongs to the technical field of radio signal positioning and detection. Aiming at the problems of large calculation amount and low accuracy of cross pulse signal pairing in a multi-aircraft co-positioning system, the method realizes high-efficiency and accurate cross pulse pairing by establishing a cross pulse boundary model, a symbol matching constraint mechanism and a related matching verification mechanism. The method comprises the steps of determining cross-pulse upper and lower boundaries according to geometric relations, correcting a search range by means of symbol matching, obtaining candidate target solutions by means of grid exhaustive search in a limited interval, and screening unique effective solutions through time and geometric consistency verification. The method can effectively reduce the computational complexity, improve the cross-pulse pairing precision and uniqueness, and is suitable for a passive positioning system under the environment of multiple targets, multiple base stations and low signal to noise ratio. Experiments prove that the invention can shorten the pairing time by about 50 percent while maintaining high positioning precision, and has higher engineering application value.

Inventors

• Xiao Zheyuan
• YANG JIAOQIAN
• GONG XINYUE
• LI JIAXIN

Assignees

• 肖喆元

Dates

Publication Date

20260508

Application Date

20251022

Claims (5)

1. 1. A grid exhaustive search cross-pulse pairing method based on correlation matching is characterized by comprising the following steps: first, a system initialization stage: acquiring two-dimensional coordinate positions of a primary station and at least two secondary stations of a multi-aircraft system Simultaneously acquiring pulse repetition intervals (Pulse Repetition Interval, PRI) of the radiation source signals to be detected, and setting the propagation speed of electromagnetic waves as c; secondly, establishing a geometric propagation model: calculating a theoretical propagation delay difference according to the space distance between each station and the target: (1) Wherein, the For the distance of the target to the i-th station, Distance from the target to the master station; Third, determining across pulse boundary intervals: establishing a cross-pulse number boundary interval according to the inter-station distance difference and the pulse repetition interval PRI: (2) Wherein the method comprises the steps of And (3) with Obtaining a cross-pulse search range for the minimum and maximum distances of the target possible area and the ith auxiliary station respectively ; Fourth, a symbol matching constraint mechanism is established: Determining the arrival sequence and time difference sign of each station signal according to the geometric relation, when Taking a positive sign with 1 less across the upper bound of the pulse traversal, otherwise taking a negative sign with 1 less across the lower bound of the traversal, thereby eliminating physically impossible combinations of the cross pulses; fifth step, grid exhaustive search phase: taking the time of receiving signals of a main station as a reference, performing traversal search on the signal time sequence of each auxiliary station according to a constraint interval, and combining all possible cross pulses Calculating a corresponding time difference positioning equation set: (3) solving candidate target coordinate solution sets through numerical iteration ; Sixth, correlation matching verification phase: Calculating correlation matching factors for the candidate solution sets, wherein the correlation matching factors comprise (1) time consistency factors representing the correlation degree of the receiving time differences of different stations, (2) geometric consistency factors representing the consistency of the sign and geometric relation of the positioning result back calculation distance difference, and judging the combination as effective pairing when the sign and the geometric relation meet a set threshold; Seventh, secondary screening and uniqueness treatment: for the candidate solution which is matched through correlation, calculating the absolute error of the physical propagation distance difference and the theoretical distance difference of the candidate solution: (4) if a plurality of combinations meeting the conditions exist, selecting a result with the largest correlation matching factor as a final pairing; Eighth step, outputting and applying: outputting unique target coordinates (x, y) and corresponding cross-pulse quantity parameters The method can be further used for target positioning, signal identification and collaborative tracking. Through the steps, the method can realize high-precision automatic pairing of the cross pulse signals under the multi-aircraft collaborative observation environment, and obviously improve pairing precision and uniqueness while reducing the complexity of exhaustive search.
2. 2. The method of claim 1, wherein the upper and lower bounds of the cross-pulse boundary model are determined by the following equations, respectively: (5) Wherein the method comprises the steps of And (3) with The maximum value and the minimum value of the distance between the target possible area and the main station are respectively, c is the propagation speed of electromagnetic waves, and PRI is the pulse repetition interval.
3. 3. The method of claim 1, wherein the correlation match verification comprises two metrics: (1) A time consistency index is based on a time difference correlation coefficient between received signals of different stations; (2) And the geometric consistency index is the symbol consistency of the distance difference and the theoretical distance difference obtained based on the positioning solution back calculation.
4. 4. When both indexes meet the threshold condition at the same time, the pairing result is considered to be valid.
5. 5. The method of claim 1, wherein the method is suitable for a passive positioning system in a multi-target, multi-base station and low signal-to-noise environment, and wherein parallel cross-pulse pairing and positioning of multiple radiation source signals can be achieved under a multi-station cooperative observation condition.

Description

Grid exhaustive search cross-pulse pairing method based on correlation matching Technical Field The invention relates to the field of radio signal positioning and detection, in particular to a cross-pulse pairing algorithm applied to a multi-aircraft co-positioning system, and particularly relates to a grid exhaustive search cross-pulse pairing method based on correlation matching, which is used for solving the problems of inaccurate cross-pulse signal pairing and long pairing time caused by smaller Pulse Repetition Interval (PRI) and larger aircraft spacing in multi-station passive positioning. Background In a multi-aircraft moveout positioning system, when the distance between each aircraft is large and the pulse repetition interval (Pulse Repetition Interval, PRI) of the target transmission signal is small, the target pulse signal received by different aircraft may occur to span the pulse period. At this time, if the accurate inter-pulse period pairing is not performed, the propagation time difference between the aircrafts of the target signal cannot be accurately calculated, and thus the TDOA (TIME DIFFERENCE of Arrival) positioning accuracy is affected. Existing multi-station observation cross-period pulse pairing algorithms (e.g., original algorithms) typically include the following steps: 1. establishing a space position model of an observation station and a target, and setting coordinates of a main station and two auxiliary stations as The coordinates of the target are。 2. The distance between the target and each station is: (1) The signal arrival delay is Where c is the propagation velocity of the electromagnetic wave. As shown in FIG. 1 (aircraft vs. target position profile) 3. The observed signal time difference between the main station and the auxiliary station is as follows: (2) 4. when the time difference exceeds the pulse period PRI, a cross-period phenomenon occurs, the number of the cross-pulses is expressed as (3) However, this algorithm has the following drawbacks in practical applications: when the number of aircrafts is large or PRI is small, the number of cross pulse combinations increases exponentially, so that the exhaustive search time is too long; when noise or geometric symmetric distribution exists in the signals, the pairing result is easy to be non-unique or incorrectly paired; the lack of a verification mechanism for the pairing result has lower accuracy. Thus, there is a need for an improved algorithm that significantly shortens the cross-pulse matching time and improves the uniqueness and stability of the pairing while maintaining accuracy. Disclosure of Invention Object of the invention Aiming at the problems of low pairing efficiency, non-unique pairing result, insufficient algorithm robustness and the like of a cross-pulse pairing algorithm in the existing multi-aircraft positioning system, the invention provides a grid exhaustive search cross-pulse pairing method based on related matching. According to the method, a space boundary model of the number of cross pulses among multiple aircrafts is established, symbol constraint is introduced to compress a search range, a correlation matching verification mechanism and a secondary matching screening criterion are adopted on the basis, and the accuracy and the uniqueness of a matching result are obviously improved, so that high-precision target positioning can be realized under the complex environments of high repetition frequency, long-distance distribution and multiple base stations. (II) technical scheme The technical scheme of the invention comprises the following main steps: 1. establishing a cross-pulse mathematical model and searching boundaries Let the space distance between two aircrafts be d, the propagation Time difference of the target signal between two stations be TOA (Time of ARRIVAL DIFFERENCE), then according to the principle that the difference between two sides of triangle in geometric relationship is smaller than the third side, it can be obtained: (4) Where c is the propagation velocity of the electromagnetic wave. As shown in FIG. 2 (schematic drawing of selection across pulse boundaries) As can be seen from equation (4), if the Pulse Repetition Interval (PRI) of the target signal is less than 2d/c, the signal between two stations may span one or more pulse periods, thereby forming a cross-pulse phenomenon. In order to further establish a cross-pulse mathematical relationship, coordinates of the target and each aircraft (the main station and the auxiliary station) are set as follows: the distance between the target and each aircraft is: (5) The corresponding signal propagation time differences are: (6) The number of cross pulses can thus be defined as: (7) equation (7) shows the number of cross pulses with a fixed aircraft geometry Only by inter-aircraft distance differences and PRI, as shown in fig. 3 (cross pulse number simulation schematic): when the difference between the two stations is large or PRI