Time difference extraction method and device suitable for medium-high repetition frequency signal positioning

Abstract

The invention discloses a time difference extraction method and device suitable for medium-high repetition frequency signal positioning, and belongs to the field of signal processing, and the method comprises the steps: inputting a maximum frequency measurement error, a maximum pulse width measurement error, a maximum signal repetition period, a minimum signal repetition period, an intra-class minimum pulse number and a minimum class number; inputting GPS pulse per second, Beidou pulse per second or synchronized local pulse per second signals among multiple stations, and performing zero clearing per second on a local clock participating in positioning of each station; carrying out signal detection on each station participating in time difference positioning to form a PDW; each station carries out clustering on the PDW set obtained by signal detection; judging the number of each site cluster and carrying out corresponding processing; otherwise, entering a subsequent step; each station shares the respective classification and the classified PDW to a certain station or a data processing center to complete inter-class pulse pairing and basic time difference measurement; and calculating to obtain a real time difference value. According to the invention, the signal processing performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of signal processing, and more specifically, to a method and device for extracting time difference applicable to medium and high pulse repetition frequency signal positioning. Background Art

[0002] Time difference positioning is a high-precision passive positioning method. The traditional time difference positioning method for radiation source signals mainly adopts the direct measurement method of time difference based on multi-station time synchronization, extracts the arrival signal difference, and calculates the spatial position of the radiation source target. When facing medium and high pulse repetition frequency radiation source signals, due to the distance difference being greater than the signal repetition period, time difference extraction ambiguity or error will occur, resulting in multiple false intersection points, namely "ghost points" or "ambiguous points" in such methods, making it difficult to obtain the accurate radiation source position. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art, provide a method and device for extracting time difference applicable to medium and high pulse repetition frequency signal positioning, solve the technical problem of false intersection points and ambiguity in medium and high pulse repetition frequency signal positioning under traditional time difference positioning, improve the signal processing performance, and accurately obtain the radiation source position.

[0004] The purpose of the present invention is achieved through the following solutions:

[0005] A method for extracting time difference applicable to medium and high pulse repetition frequency signal positioning includes the following steps:

[0006] S1, input the maximum frequency measurement error MaxRF_T, the maximum pulse width measurement error MaxPW_T, the maximum signal repetition period Max_Pri, the minimum signal repetition period Min_Pri, the minimum number of pulses within a class MinPDW_N, and the minimum number of classes MinCPDW_N;

[0007] S2, input the GPS second pulse, the Beidou second pulse, or the locally synchronized second pulse signal among multiple stations, and clear the local clocks of each station participating in the positioning every second;

[0008] S3, each station participating in time difference positioning performs signal detection to form PDW;

[0009] S4, each station performs clustering on the PDW set obtained by signal detection respectively;

[0010] S5, if the number of clusters of each station is less than MinCPDW_N, return to step S3; otherwise, enter step S6;

[0011] S6, each station shares its classified and classified PDW to a certain station or data processing center to complete inter-class pulse pairing and basic time difference measurement;

[0012] S7. Calculate the true time difference.

[0013] Further, in step S3, the PDW includes the frequency RF_ij, the pulse width PW_ij, the modulation mode MOD_ij, and the time of arrival ToA_ij. Denote the PDW set obtained by signal detection at the i-th site as PDW_i.

[0014] Further, in step S4, each site performs clustering on the PDW set obtained by signal detection, specifically including the following sub-steps:

[0015] The specific steps for clustering the PDW set PDW_i of the i-th site to obtain the PDW classes after distance calculation are as follows:

[0016] Step a), initialize the number of classifications CPDW_i_n to 0, the classification set CPDW_i to an empty set, and the PDW set corresponding to the classification set CPDW_i_PDW to an empty set;

[0017] Step b), if the number of pulses in PDW_i is less than MinPDW_N, then exit; otherwise, proceed to c);

[0018] Step c), set the temporary pulse set PDW_TEMP to an empty set and the temporary category to CPDW_TEMP;

[0019] Step d), take out the first pulse pdw_t of PDW_i and delete pdw_t from PDW_i;

[0020] Step e), if CPDW_i_n is 0, then add pdw_t to PDW_TEMP (named), and use the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t as the information of the temporary category CPDW_TEMP; otherwise, proceed to f);

[0021] Step f), take out each class in CPDW_i one by one, denote the k-th class as CPDW_i_k, and compare the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t with the frequency RF_i_k, pulse width PW_i_k, and modulation mode Mod_i_k of CPDW_i_k; when the condition in formula (1) is satisfied, add pdw_t to the end of the pulse set CPDW_i_k_PDW of the corresponding class and stop searching for other classes; update the frequency RF_i_k and pulse width PW_i_k parameters of the found class CPDW_i_k, and the values are the average of the frequencies and the average of the pulse widths in CPDW_i_j_PDW respectively;

[0022]

[0023] g), if no class satisfying formula (1) is found, compare the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t with the frequency RF_TEMP, pulse width PW_TEMP, and modulation mode Mod_TEMP of the temporary pulse set CPDW_TEMP; if formula (2) is satisfied, add pdw_t to the end of the elements of the PDW_TEMP set; at the same time, update the frequency RF_TEMP and pulse width PW_TEMP to the average value of the frequencies and the average value of the pulse widths in PDW_TEMP;

[0024]

[0025] h), when the number of pulses in PDW_TEMP is greater than the minimum number of pulses MinPDW_N within a class, add the temporary class CPDW_TEMP and the corresponding PDW set PDW_TEMP as elements to CPDW_i and CPDW_i_PDW respectively;

[0026] i), return to step d) until PDW_i is empty;

[0027] j), sort the PDWs in each class in CPDW_i according to the arrival time, denote the k-th class as CPDW_i_k, use the arrival time of the latter pulse minus the arrival time of the former pulse to obtain the arrival time difference set △ToA; count the number of elements in each interval of △ToA set from Min_Pri to Max_Pri with the maximum pulse width measurement error MaxPW_T as the interval; take the mean value of each element in the interval with the largest number of elements as the repetition period value of the CPDW_i_k class.

[0028] Furthermore, in step S6, each station shares its classified and classified PDWs to a certain station or data processing center to complete inter-class pulse pairing and basic time difference measurement, which specifically includes the following sub-steps:

[0029] Denote the k-th class before classification as CPDW_i_k, and denote the k-th class after classification as CPDW_i_k_PDW;

[0030] Step a), pair class with class, traverse each PDW class of each station, if the frequency difference between two PDW classes of two stations is not greater than the maximum frequency measurement error MaxRF_T, the pulse width difference is not greater than the maximum pulse width measurement error MaxPW_T, and the modulation modes are the same, then the two PDW classes are considered to be the same class;

[0031] Step b), basic time difference measurement. After class-to-class pairing, assume that the k-th class CPDW_i_k of the i-th station and the l-th class CPDW_j_l of the j-th station belong to the same class, and the corresponding pulse sets are CPDW_i_k_PDW and CPDW_j_l_PDW; denote the minimum number of pulses in the pulse sets CPDW_i_k_PDW and CPDW_j_l_PDW as N_i_k, extract the first N_i_k pulses from the two sets, and calculate the arrival time difference sequence △ToA_i_k; use △ToA_i_k to perform modulo operation on the repetition period of CPDW_i_k, and perform average calculation, that is, obtain the basic time difference value △ToA_b_i_k under the repetition periods of CPDW_i_k and CPDW_j_l, and form the following data table a;

[0032] Table a

[0033] Serial number Station i number Station j number Station i class number Station j class number Base time difference value 1 i1 j1 k1 l1 △ToA_b_i_k1 2 i1 j1 k1 l1 △ToA_b_i_k2 …… …… …… …… …… ……

[0034] Further, in step S7, the calculation of the true time difference value specifically includes the following sub-steps: Solve the following formula (3) for the deblurring of the time difference measurement between pulses to obtain the true time difference value △T_F:

[0035]

[0036] In the formula, PRI_i_k and PRI_j_l respectively represent the repetition period values of CPDW_i_k and CPDW_j_l, PRI_ij_kl is the value calculated from PRI_i_k and PRI_j_l, and Δξ is a random error less than 2 times MaxPW_T.

[0037] A time difference extraction device applicable to the positioning of medium and high PRF signals includes a processor and a memory. A computer program is stored in the memory, and when the computer program is loaded by the processor, it executes the method described in any one of the above.

[0038] The beneficial effects of the present invention include:

[0039] The method of the present invention overcomes the technical problem of ambiguity in time difference extraction for medium and high PRF signals in traditional time difference positioning, and can be widely applied to the optimization and improvement of various signal processing devices. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 Schematic diagram of the collaborative time difference positioning scenario of the typical medium and high pulse repetition frequency signals constructed for the solution of the embodiment of the present invention. Detailed implementation manners

[0042] All features disclosed in all embodiments in this specification, or all steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or extended and replaced in any manner.

[0043] The specific implementation process of the present invention is as follows:

[0044] In a preferred embodiment, it particularly relates to the signal processing application under the networked operation of equipment. Aiming at the problem of false intersection points in the positioning of medium and high pulse repetition frequency signals under traditional time difference positioning, a method for extracting time difference suitable for medium and high pulse repetition frequency signals is proposed to make up for the deficiencies of traditional methods. Specifically, the method of the embodiment of the present invention includes the following steps:

[0045] Step 1: Input the maximum frequency measurement error MaxRF_T, the maximum pulse width measurement error MaxPW_T, the maximum signal repetition period Max_Pri, the minimum signal repetition period Min_Pri, the minimum number of pulses within a class MinPDW_N, and the minimum number of classes MinCPDW_N;

[0046] Step 2: Input the GPS second pulse, the Beidou second pulse, or the locally synchronized second pulse signals among multiple stations, and clear the local clocks of each station participating in the positioning every second;

[0047] Step 3: Each station participating in the time difference positioning performs signal detection to form PDWs. Denote the PDW set obtained by signal detection at the i-th station as PDW_i, and the j-th PDW collected at the i-th station as PDW_i(j), which includes several dimensional information such as frequency RF_ij, pulse width PW_ij, modulation mode MOD_ij, and time of arrival ToA_ij;

[0048] Step 4: Each station performs clustering on the PDW sets obtained by signal detection respectively. Taking the PDW set PDW_i of the i-th station as an example, the specific steps for clustering to obtain the PDW classes after distance are as follows:

[0049] a) Initialize the number of classifications CPDW_i_n to 0, the classification set CPDW_i to an empty set, and the PDW set corresponding to the classification set CPDW_i (denoted as CPDW_i_PDW) to an empty set;

[0050] b) If the number of pulses in PDW_i is less than MinPDW_N, then exit; otherwise, proceed to c);

[0051] c) Set the temporary pulse set PDW_TEMP to be empty, and the temporary category to CPDW_TEMP;

[0052] d) Take out the first pulse of PDW_i as pdw_t, and delete pdw_t from PDW_i;

[0053] e) If CPDW_i_n is 0, then add pdw_t to PDW_TEMP, and use the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t as the information of the temporary category CPDW_TEMP; otherwise, go to f);

[0054] f) Take out the categories in CPDW_i one by one (denote the k-th category as CPDW_i_k), and compare the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t with the frequency RF_i_k, pulse width PW_i_k, and modulation mode Mod_i_k of CPDW_i_k. When the (*) formula is satisfied, add pdw_t to the end of the pulse set CPDW_i_k_PDW of the corresponding category CPDW_i_k, and stop searching for other categories. Update the frequency RF_i_k and pulse width PW_i_k parameters of the found category CPDW_i_k, and the values are the average of the frequencies and the average of the pulse widths in CPDW_i_j_PDW respectively;

[0055]

[0056] g) If no category satisfying (1) is found, compare the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t with the frequency RF_TEMP, pulse width PW_TEMP, and modulation mode Mod_TEMP of the temporary pulse set CPDW_TEMP. If the following formula is satisfied, add pdw_t to the end of the elements of the PDW_TEMP set. At the same time, update the frequency RF_TEMP and pulse width PW_TEMP to be the average of the frequencies and the average of the pulse widths in PDW_TEMP respectively;

[0057]

[0058] h) When the number of pulses in PDW_TEMP is greater than the minimum number of pulses MinPDW_N within a category, add the temporary category CPDW_TEMP and the corresponding PDW set PDW_TEMP as elements to CPDW_i and CPDW_i_PDW respectively;

[0059] i) Return to step d) until PDW_i is empty.

[0060] j) Sort the PDWs in each class in CPDW_i (denote the k-th class as CPDW_i_k) according to the arrival time. Subtract the arrival time of the previous pulse from the arrival time of the next pulse to obtain the arrival time difference set △ToA. Count the number of elements in each interval of △ToA set from Min_Pri to Max_Pri at an interval of the maximum pulse width measurement error MaxPW_T. Take the mean value of each element in the interval with the largest number of elements as the repetition period value of the CPDW_i_k class.

[0061] Step 5, if the number of clusters at each site is less than MinCPDW_N, then return to Step (3); otherwise, proceed to Step (6);

[0062] Step 6, each site shares its respective classification (denote the k-th class as CPDW_i_k) and the classified PDWs (denote the k-th class as CPDW_i_k_PDW) to a certain site or data processing center to complete inter-class pulse pairing and basic time difference measurement. The steps are as follows:

[0063] a) Class pairing

[0064] Traverse each PDW class of each site. If the frequency difference between two PDW classes of two sites is not greater than the maximum frequency measurement error MaxRF_T, the pulse width difference is not greater than the maximum pulse width measurement error MaxPW_T, and the modulation methods are the same, then the two PDW classes are considered to be the same class.

[0065] b) Basic time difference measurement

[0066] Assume that after class pairing, the k-th class CPDW_i_k of the i-th site and the l-th class CPDW_j_l of the j-th site belong to the same class, and the corresponding pulse sets are CPDW_i_k_PDW and CPDW_j_l_PDW.

[0067] Denote the minimum number of pulses in the pulse sets CPDW_i_k_PDW and CPDW_j_l_PDW as N_i_k. Take the first N_i_k pulses from the two sets and calculate the arrival time difference sequence △ToA_i_k (the calculation method is to subtract the arrival time of the pulse in CPDW_i_k_PDW from the arrival time of the pulse in CPDW_j_l_PDW at the same order one by one). Use △ToA_i_k to perform modulo operation on the repetition period of CPDW_i_k and perform average calculation, that is, obtain the basic time difference value △ToA_b_i_k under the repetition periods of CPDW_i_k and CPDW_j_l, and form the following data table a.

[0068] Table a

[0069] Serial number Station i number Station j number Station i class number Station j class number Base time difference value 1 i1 j1 k1 l1 △ToA_b_i_k1 2 i1 j1 k1 l1 △ToA_b_i_k2 …… …… …… …… …… ……

[0070] Step 7: Based on Step 5, solve the following formula (3) for the unambiguous solution of the time difference between pulses to obtain the true time difference value ΔT_F. In the formula, PRI_i_k and PRI_j_l respectively represent the repetition period values of CPDW_i_k and CPDW_j_l. Δξ is a random error less than 2 times MaxPW_T.

[0071]

[0072] In other embodiments of the present invention, the specific implementation steps are as follows:

[0073] (1) Construct a collaborative time difference positioning scenario for typical medium and high PRF signals, as Figure 1 shown. The positioning stations are respectively Slave Station 1, Slave Station 2, and Slave Station 3. The two-dimensional coordinates of the three stations are (0, 0), (-30, 10), and (30, 20) in sequence. Set the two-dimensional coordinates of the positioning target to (-10, 100), and the coordinate unit is km;

[0074] (2) Input the maximum frequency measurement error MaxRF_T, the maximum pulse width measurement error MaxPW_T, the maximum signal repetition period Max_Pri, the minimum signal repetition period Min_Pri, the minimum number of pulses within a class MinPDW_N, and the minimum number of classes MinCPDW_N, as shown in Table 2;

[0075] (3) The three stations perform signal detection to form PDW data, as shown in Table 3;

[0076] (4) The three stations respectively cluster the PDW formed by detection, and calculate the frequency, pulse width, modulation method, repetition period, etc. of each class to obtain Table 4;

[0077] (5) Station 2 and Station 3 share the clustering results to Station 1, and Station 1 performs inter-class pairing and basic time difference measurement, and the results are shown in Table 4;

[0078] (6) Based on the basic time difference values, solve for the unambiguous true time difference values. The time difference between Station 1 and Station 2 is 27681.78 ns, and the time difference between Station 1 and Station 3 is 36859.78 ns.

[0079] Meanwhile, according to the true target position and the site positions in step (1), the theoretical time differences between site 1 and site 2, and between site 1 and site 3 are 27677.71 ns and 36853.46 ns respectively. Using the traditional time difference calculation method, the time differences between site 1 and site 2, and between site 1 and site 3 obtained are the basic time differences in Table 4, resulting in time difference ambiguity and unable to support positioning measurement. However, after adopting the present invention, the time differences between site 1 and site 2, and between site 1 and site 3 can be calculated, and they are basically consistent with the theoretical time differences (the difference is less than 10 ns), which can meet the positioning requirements.

[0080] Table 1

[0081] MaxRF_T MaxPW_T Max_Pri Min_Pri MinPDW_N MinCPDW_N 0.5MHz 0.01us 10ms 0.01ms 5 2

[0082] Table 2

[0083]

[0084]

[0085] Table 3

[0086]

[0087]

[0088] Table 4

[0089]

[0090] Table 5

[0091]

[0092] The units involved in the embodiments of the present invention can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not constitute a limitation to the unit itself in some cases.

[0093] According to one aspect of the embodiments of the present invention, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the above various optional implementation manners.

[0094] As another aspect, an embodiment of the present invention further provides a computer-readable medium, which may be included in the electronic device described in the above embodiments; or may exist alone without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the one or more programs are executed by an electronic device, the electronic device implements the method described in the above embodiments.

Claims

1. A time difference extraction method suitable for positioning of medium and high repetition frequency signals, characterized in that: The following steps are involved: S1, input the maximum frequency measurement error MaxRF_T, the maximum pulse width measurement error MaxPW_T, the maximum signal repetition period Max_Pri, the minimum signal repetition period Min_Pri, the minimum number of pulses within the class MinPDW_N, and the minimum number of classes MinCPDW_N; S2, input GPS second pulse, Beidou second pulse or local second pulse signal synchronized between multiple stations, and reset the local clock of each station involved in positioning every second; S3, each station participating in the time difference positioning performs signal detection to form PDW; S4, each site clusters the PDW set obtained by signal detection; S5, if the number of each site cluster is less than MinCPDW_N, return to step S3; otherwise, go to step S6; S6, each site shares its own classification and classified PDW to a certain site or data processing center to complete inter-class pulse pairing and basic time difference measurement; S7, calculating the real time difference value.

2. The time difference extraction method suitable for positioning of medium and high repetition rate signals according to claim 1, characterized in that: In step S3, the PDW includes frequency RF_ij, pulse width PW_ij, modulation mode MOD_ij and arrival time ToA_ij, and the PDW set obtained by the signal detection of the i-th site is denoted as PDW_i.

3. The time difference extraction method suitable for positioning of medium and high repetition rate signals according to claim 1, characterized in that: In step S4, each station clusters the PDW sets obtained by signal detection, which specifically includes sub-steps: Assume that for the PDW set PDW_i of the i-th site, the specific steps of clustering the PDW class after the distance is as follows: Step a), initializing the number of categories CPDW_i_n to 0, the category set CPDW_i to an empty set, and the PDW set CPDW_i_PDW corresponding to the category set CPDW_i to an empty set; Step b), if the number of pulses in PDW_i is less than MinPDW_N, exit; otherwise, enter c); Step c), setting the temporary pulse set PDW_TEMP to empty and the temporary category to CPDW_TEMP; Step d), taking out the first pulse pdw_t of PDW_i, and deleting pdw_t from PDW_i; Step e), if CPDW_i_n is 0, pdw_t is added to PDW_TEMP, and the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t are used as the information of the temporary category CPDW_TEMP; otherwise, go to f); Step f), take out the classes in CPDW_i one by one, record the kth class as CPDW_i_k, compare the frequency rf_t, pulse width pw_t, modulation mode Mod_t of pdw_t with the frequency RF_i_k, pulse width PW_i_k, modulation mode Mod_i_k of CPDW_i_k; when formula (1) is satisfied, add pdw_t to the end of the pulse set CPDW_i_k_PDW of the corresponding class CPDW_i_k, and stop searching for other classes; update the frequency RF_i_k and pulse width PW_i_k parameters of the found class CPDW_i_k, and take the values ​​as the average value of the frequency and the average value of the pulse width in CPDW_i_j_PDW respectively; g), if no class satisfying formula (1) is found, the frequency rf_t, pulse width pw_t, and modulation mode Mod_t of pdw_t are compared with the frequency RF_TEMP, pulse width PW_TEMP, and modulation mode Mod_TEMP of the temporary pulse set CPDW_TEMP; if formula (2) is satisfied, pdw_t is added to the end of the PDW_TEMP set element; at the same time, the frequency RF_TEMP and pulse width PW_TEMP are updated to the average value of the frequency and the average value of the pulse width in PDW_TEMP; h), when the number of pulses in PDW_TEMP is greater than the minimum number of pulses in the class MinPDW_N, the temporary class CPDW_TEMP and the corresponding PDW set PDW_TEMP are added as elements to CPDW_i and CPDW_i_PDW respectively; i), return to step d), until PDW_i is empty; j), sort the PDWs in each class in CPDW_i according to the arrival time, record the kth class as CPDW_i_k, and subtract the arrival time of the previous pulse from the arrival time of the next pulse to obtain the arrival time difference set △ToA; count the number of elements in each interval of the △ToA set from Min_Pri to Max_Pri, with the maximum pulse width measurement error MaxPW_T as the interval; the mean of each element in the interval with the largest number of elements is the repetition period value of the CPDW_i_k class.

4. The time difference extraction method suitable for positioning of medium and high repetition rate signals according to claim 3, characterized in that: In step S6, each site shares its own classification and the classified PDW to a certain site or data processing center to complete the inter-class pulse pairing and basic time difference measurement, which specifically includes the following sub-steps: The k-th class before classification is recorded as CPDW_i_k, and the k-th class after classification is recorded as CPDW_i_k_PDW; Step a), pairing classes with classes, traversing each PDW class of each site, if the difference between the frequencies of the two PDW classes of the two sites is not greater than the maximum frequency measurement error MaxRF_T, the difference in pulse width is not greater than the maximum pulse width measurement error MaxPW_T, and the modulation modes are the same, then the two PDW classes are considered to be the same class; Step b), basic time difference measurement, assuming that after class pairing, the k-th class CPDW_i_k of the ith site and the l-th class CPDW_j_l of the j-th site belong to the same class, and the corresponding pulse sets are CPDW_i_k_PDW and CPDW_j_l_PDW; the minimum number of pulses of the pulse sets CPDW_i_k_PDW and CPDW_j_l_PDW is recorded as N_i_k, and the first N_i_k pulses in the two sets are taken out to calculate the arrival time difference sequence △ToA_i_k; △ToA_i_k is used to perform a remainder calculation on the repetition period of CPDW_i_k, and an average calculation is performed to obtain the basic time difference value △ToA_b_i_k under the repetition period of CPDW_i_k and CPDW_j_l, that is, the following data table a is formed; Table a 。 5. The time difference extraction method suitable for positioning of medium and high repetition rate signals according to claim 4, characterized in that: In step S7, the calculation of the real time difference value specifically includes the following sub-steps: solving the following equation (3) to defuzzify the pulse-to-pulse time difference measurement and obtain the real time difference value △T_F: Where PRI_i_k and PRI_j_l represent the repetition period values ​​of CPDW_i_k and CPDW_j_l respectively, PRI_ij_kl is the value calculated by PRI_i_k and PRI_j_l, and Δξ is the random error less than 2 times MaxPW_T.

6. A time difference extraction device suitable for positioning of medium and high repetition frequency signals, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is loaded by the processor, the method according to any one of claims 1 to 5 is executed.

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