TOA abnormal value filtering method based on TC-OFDM positioning system

Abstract

The invention provides a TOA abnormal value filtering method based on a TC-OFDM positioning system, and relates to the field of positioning navigation. According to the method, signals are radiated through multiple base stations, and a terminal receives multiple paths of signals; recording the time of arrival TOA of the signals received from each base station, and counting the number N of the signals; checking the number of signals, sequentially calculating the time difference with the TOA values of other base stations according to the TOA value of each base station, and adding one to the error code Ei of the base station when the absolute value of the time difference is greater than a threshold value T; if the error code Ei of the current base station is equal to N minus one, abandoning the current base station and the TOA value of the current base station, and subtracting one from N; after TOA abnormal values are filtered out, if the number of the remaining effective TOA values is still larger than or equal to M, positioning calculation is conducted according to the time difference TDOA between the base stations. The problem of false capturing caused by shielding, interference or different signal quality of each base station is solved. According to the method, the abnormal TOA value caused by environmental factors is effectively identified and eliminated, and the positioning precision is improved.

Description

Technical Field

[0001] This document relates to the field of positioning and navigation, and in particular to a TOA outlier filtering method based on a TC-OFDM positioning system. Background Art

[0002] The ranging positioning of the TC-OFDM positioning system is based on the TDOA (Time Difference Of Arrival) method, that is, the positioning method is based on the difference in distance between each base station (hereinafter referred to as Anchor) and the receiver object (hereinafter referred to as Tag) to infer the relative position of the object to be positioned relative to each reference base station by solving a group of nonlinear hyperbolic equations. Therefore, it is only necessary to measure the arrival time difference (TDOA) of the signal sent by each Anchor to the Tag to obtain the corresponding distance difference. In the TC-OFDM positioning system, the arrival time of each Anchor at the Tag is TOA (Time of Arrival), and the difference in TOA between the two Anchors arriving at the Tag is TDOA. The TOA unit adopts the pseudo code phase measurement method, that is, the TOA value range is between 0 and 10230.

[0003] In actual applications, due to obstruction, interference or different signal quality of each base station, there may be false capture. The calculated TOA value of a certain route is abnormal, which leads to abnormal positioning.

[0004] Therefore, there is an urgent need for an outlier processing method to solve the problem of false capture caused by obstruction, interference or different signal qualities of each base station. Summary of the invention

[0005] This specification provides a TOA outlier filtering method based on a TC-OFDM positioning system, which is used to solve the problem of false capture caused by obstruction, interference or different signal qualities of each base station.

[0006] In a first aspect, this specification provides a TOA outlier filtering based on a TC-OFDM positioning system, including:

[0007] Multiple base stations radiate signals, and the terminal receives multiple signals;

[0008] Record the arrival time TOA of the signals received from each base station, and count the number of received signals N and the base station identifier corresponding to the signal;

[0009] Check the number of signals to determine whether the number of signals N is greater than or equal to the specified number M;

[0010] According to the TOA value of each base station, the time difference with the TOA value of other base stations is calculated in turn. When the absolute value of the time difference is greater than the threshold T, the error code E of the base station isi plus one;

[0011] If the error code of the current base station is E i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one;

[0012] After filtering out TOA outliers, if the number of remaining valid TOA values ​​is still greater than or equal to M, the final positioning calculation is performed based on the time difference TDOA between each base station.

[0013] In the second aspect, this specification provides a TOA outlier filtering device based on a TC-OFDM positioning system, including: a multi-base station signal sending and receiving module, a received signal recording module, a signal quantity checking module, an error detection module, an outlier identification and exclusion module, and a positioning calculation module, wherein:

[0014] The multi-base station signal sending and receiving module is used for multiple base stations to radiate signals and the terminal to receive multi-path signals;

[0015] The received signal recording module is used to record the arrival time TOA of the signal received from each base station, and count the number N of received signals and the base station identifier corresponding to the signal;

[0016] The signal quantity checking module is used to check the signal quantity and determine whether the signal quantity N is greater than or equal to the specified quantity M;

[0017] The error detection module is used to calculate the time difference between the TOA value of each base station and the TOA value of other base stations in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i plus one;

[0018] The abnormal value identification and elimination module is used to identify and eliminate the error code E of the current base station. i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one;

[0019] The positioning calculation module is used to perform a final positioning calculation based on the time difference TDOA between each base station if the number of remaining valid TOA values ​​is still greater than or equal to M after filtering out TOA abnormal values.

[0020] The beneficial effects of the present invention are as follows:

[0021] This specification provides a TOA outlier filtering method based on a TC-OFDM positioning system. The method radiates signals through multiple base stations, and a terminal receives multiple signals; records the arrival time TOA of the signals received from each base station, and counts the number of received signals N; checks the number of signals, and calculates the time difference with the TOA values ​​of other base stations in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than a threshold value T, the error code E of the base station is i Add one; if the error code of the current base station is E i If it is equal to N minus one, the current base station and the TOA value of the current base station are discarded, and N is reduced by one; after filtering out the TOA abnormal values, if the number of remaining valid TOA values ​​is still greater than or equal to M, the positioning calculation is performed based on the time difference TDOA between each base station. This solves the problem of false capture caused by obstruction, interference or different signal quality of each base station. This method can effectively identify and eliminate abnormal TOA values ​​caused by environmental factors, thereby improving positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of this specification and constitute a part of this specification. The illustrative embodiments and descriptions of this specification are used to explain this specification and do not constitute an improper limitation on this specification. In the drawings:

[0023] Figure 1 It is a schematic diagram of a TOA outlier filtering method based on a TC-OFDM positioning system provided in an embodiment of this specification;

[0024] Figure 2 is a schematic diagram of a TC-OFDM positioning system provided in an embodiment of this specification;

[0025] Figure 3 It is a schematic diagram of a TOA outlier filtering device based on a TC-OFDM positioning system provided in an embodiment of this specification. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and their corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this document.

[0027] The technical solutions provided by the embodiments of this specification are described in detail below in conjunction with the accompanying drawings. Specific embodiment one:

[0029] This embodiment provides a TOA outlier filtering method based on a TC-OFDM positioning system. Figure 1 ,include:

[0030] Step 102: Multiple base stations radiate signals, and the terminal receives multiple signals;

[0031] The number of base stations radiating signals is N, where N is a positive integer and N is greater than or equal to M.

[0032] See also Figure 2 , this embodiment provides a priority scheme M=3;

[0033] At least three base stations (Anchors) send out signals, and the terminal (Tag) receives these multiple signals simultaneously.

[0034] Step 104: Record the arrival time TOA of the signal received from each base station, and count the number N of received signals and the base station identifier corresponding to the signal;

[0035] The arrival times of the signals received from the respective base stations are TOA1, TOA2, ... TOAN.

[0036] Step 106, check the number of signals to determine whether the number of signals N is greater than or equal to the specified number M;

[0037] If N is greater than or equal to M, then continue to execute step 108;

[0038] If N is less than M, it returns to continue receiving signals and records the arrival time TOA of the signals received from each base station.

[0039] Based on this, the situation where insufficient signals are received and positioning cannot be solved is ruled out.

[0040] Step 108: According to the TOA value of each base station, the time difference with the TOA value of other base stations is calculated in turn. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i plus one;

[0041] Among them, the error code of the base station is E i It is expressed as:

[0042] in, is an indicator function;

[0043] When|TOA i -TOA j When |>T is established, the error code Ei takes the value of 1, otherwise it takes the value of 0.

[0044] Based on this, in order to determine whether the TOA value is abnormal compared with other TOA values.

[0045] Step 110: If the error code of the current base station is E i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one;

[0046] Further, the error code E of each base station is determined in turn. i Whether it is equal to the number of received signals N minus one, until the absolute value of the difference between the TOA value of the remaining valid base station and the TOA value of other base stations does not exceed the threshold T.

[0047] Specific example:

[0048] Set the threshold T = 100:

[0049] TOA1 TOA2 TOA3 TOA4 Pseudocode value 5352.3 5352.8 8205.1 5352.9

[0050] After pairwise subtraction, it is found that the difference between TOA3 and other TOA values ​​is greater than the threshold T. In this case, TOA3 is considered an abnormal value and does not participate in the positioning calculation.

[0051] Based on this, the TOA outliers can be effectively eliminated and will not participate in the positioning solution, thus improving the positioning accuracy.

[0052] Step 112: After filtering out TOA abnormal values, if the number of remaining valid TOA values ​​is still greater than or equal to M, the final positioning calculation is performed according to the time difference TDOA between each base station.

[0053] The calculation method of the time difference TDOA value between each base station is:

[0054] TDOAn=TOAn-TOA1;

[0055] Wherein, n=1, 2, 3, ..., N1, N1 represents the number of valid base stations, and TOAn represents the arrival time of the signal received from the nth base station.

[0056] In summary, in this embodiment, multiple base stations radiate signals, and the terminal receives multiple signals; the arrival time TOA of the signals received from each base station is recorded, and the number of received signals N is counted; the number of signals is checked, and the time difference with the TOA value of other base stations is calculated in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i Add one; if the error code of the current base station is E iIf it is equal to N minus one, the current base station and the TOA value of the current base station are discarded, and N is reduced by one; after filtering out the TOA abnormal values, if the number of remaining valid TOA values ​​is still greater than or equal to M, the positioning calculation is performed based on the time difference TDOA between each base station. This solves the problem of false capture caused by obstruction, interference or different signal quality of each base station. This method can effectively identify and eliminate abnormal TOA values ​​caused by environmental factors, thereby improving positioning accuracy. Specific embodiment 2:

[0058] This embodiment provides a solution for filtering TOA outliers based on the TC-OFDM positioning system, aiming to solve the problem of false capture caused by obstruction, interference or different signal quality of each base station in practical applications. Specifically, when the calculated TOA value of a certain path is abnormal, inaccurate positioning will result. The specific implementation steps of this method are as follows:

[0059] 1. Multi-base station signal transmission: At least three base stations (Anchors) send signals, and the terminal (Tag) receives these multiple signals simultaneously.

[0060] 2. Received signal record: record the arrival time (TOA) of the signal received from each base station, namely: TOA1, TOA2, TOA3, TOA4,…

[0061] 3. Signal identification: record the number of received signals N and the corresponding base station identification.

[0062] 4. Check the number of signals: Determine whether the number of signals N is greater than or equal to three; if it is less than three, no further processing is performed.

[0063] 5. Error detection: For each base station's TOA value, subtract it from the TOA values ​​of other base stations in turn. When the absolute value of the difference is greater than the threshold T, the error code Ei of the base station is increased by 1. That is:

[0064] in, is an indicator function, when |TOA i -TOA j The value is 1 when |>T holds, otherwise it is 0.

[0065] 6. Identification and elimination of outliers: If the error code Ei of a base station is equal to the number of received signals N minus one, it is considered that the absolute value of the difference between the TOA value of this base station and the TOA values ​​of all other base stations is greater than the threshold T. At this time, the base station should be discarded, its TOA value will not be involved in the positioning calculation, and the number of received signals N will be reduced by one.

[0066] 7. Positioning calculation: After filtering out the outliers, if the number of remaining valid TOA values ​​is still greater than or equal to three, the final positioning calculation is performed based on the time difference (TDOA) between each base station.

[0067] For example, setting the threshold T = 100:

[0068] TOA1 TOA2 TOA3 TOA4 Pseudocode value 5352.3 5352.8 8205.1 5352.9

[0069] After pairwise subtraction, it is found that the difference between TOA3 and other TOA values ​​is greater than the threshold T. In this case, TOA3 is considered an abnormal value and does not participate in the positioning calculation.

[0070] This solution can effectively identify and eliminate abnormal TOA values ​​caused by environmental factors, thereby improving positioning accuracy.

[0071] In summary, in this embodiment, multiple base stations radiate signals, and the terminal receives multiple signals; the arrival time TOA of the signals received from each base station is recorded, and the number of received signals N is counted; the number of signals is checked, and the time difference with the TOA value of other base stations is calculated in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i Add one; if the error code of the current base station is E i If it is equal to N minus one, the current base station and the TOA value of the current base station are discarded, and N is reduced by one; after filtering out the TOA abnormal values, if the number of remaining valid TOA values ​​is still greater than or equal to M, the positioning calculation is performed based on the time difference TDOA between each base station. This solves the problem of false capture caused by obstruction, interference or different signal quality of each base station. This method can effectively identify and eliminate abnormal TOA values ​​caused by environmental factors, thereby improving positioning accuracy. Specific embodiment three:

[0073] This embodiment is a TOA outlier filtering device based on a TC-OFDM positioning system. Figure 3 , including: a multi-base station signal sending and receiving module 301, a received signal recording module 302, a signal quantity checking module 303, an error detection module 304, an abnormal value identification and elimination module 305, and a positioning calculation module 306, wherein:

[0074] The multi-base station signal sending and receiving module 301 is used for multiple base stations to radiate signals and the terminal to receive multiple signals;

[0075] The received signal recording module 302 is used to record the arrival time TOA of the signal received from each base station, and count the number N of received signals and the base station identifier corresponding to the signal;

[0076] The signal quantity checking module 303 is used to check the signal quantity and determine whether the signal quantity N is greater than or equal to the specified quantity M;

[0077] The error detection module 304 is used to calculate the time difference between each base station and the TOA value of other base stations in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i plus one;

[0078] The abnormal value identification and elimination module 305 is used to identify and eliminate the abnormal value of the current base station. i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one;

[0079] The positioning calculation module 306 is used to perform a final positioning calculation according to the time difference TDOA between each base station if the number of remaining valid TOA values ​​is still greater than or equal to M after filtering out TOA abnormal values.

[0080] Optionally, the number of base stations radiating signals is N, where N is a positive integer and N is greater than or equal to a specified number M.

[0081] Optionally, the device further comprises: a signal quantity insufficient module, wherein the signal quantity insufficient module is used to:

[0082] If N is less than M, it returns to continue receiving signals and records the arrival time TOA of the signals received from each base station.

[0083] Optional, error code E of the base station i It is expressed as:

[0084] in, is an indicator function;

[0085] When|TOA i -TOA j |>When T is established, error code E i The value is 1, otherwise it is 0.

[0086] Optionally, the device further includes: a valid base station error code determination module, wherein the valid base station error code determination module is used to:

[0087] Determine the error code E of each base station in turn i Whether it is equal to the number of received signals N minus one, until the absolute value of the difference between the TOA value of the remaining valid base station and the TOA value of other base stations does not exceed the threshold T.

[0088] Optionally, the time difference TDOA value between each base station is calculated as follows:

[0089] TDOAn=TOAn-TOA1;

[0090] Wherein, n=1, 2, 3, ..., N1, N1 represents the number of valid base stations, and TOAn represents the arrival time of the signal received from the nth base station.

[0091] Optionally, M=3.

[0092] In summary, in this embodiment, multiple base stations radiate signals, and the terminal receives multiple signals; the arrival time TOA of the signals received from each base station is recorded, and the number of received signals N is counted; the number of signals is checked, and the time difference with the TOA value of other base stations is calculated in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i Add one; if the error code of the current base station is E i If it is equal to N minus one, the current base station and the TOA value of the current base station are discarded, and N is reduced by one; after filtering out the TOA abnormal values, if the number of remaining valid TOA values ​​is still greater than or equal to M, the positioning calculation is performed based on the time difference TDOA between each base station. This solves the problem of false capture caused by obstruction, interference or different signal quality of each base station. This method can effectively identify and eliminate abnormal TOA values ​​caused by environmental factors, thereby improving positioning accuracy.

[0093] The above description is only a preferred embodiment of this specification and is not intended to limit this specification. For those skilled in the art, this specification may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the protection scope of this specification.

Claims

1. A TOA outlier filtering method based on TC-OFDM positioning system, characterized in that: include: Multiple base stations radiate signals, and the terminal receives multiple signals; Record the arrival time TOA of the signals received from each base station, and count the number of received signals N and the base station identifier corresponding to the signal; Check the number of signals to determine whether the number of signals N is greater than or equal to the specified number M; According to the TOA value of each base station, the time difference with the TOA value of other base stations is calculated in turn. When the absolute value of the time difference is greater than the threshold T, the error code E of the base station is i plus one; If the error code of the current base station is E i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one; After filtering out TOA outliers, if the number of remaining valid TOA values ​​is still greater than or equal to M, the final positioning calculation is performed based on the time difference TDOA between each base station.

2. The method according to claim 1, characterized in that The number of base stations radiating signals is N, where N is a positive integer and is greater than or equal to a specified number M.

3. The method according to claim 2, characterized in that After checking the number of signals and determining whether the number of signals N is greater than or equal to the specified number M, the method further includes: If N is less than M, it returns to continue receiving signals and records the arrival time TOA of the signals received from each base station.

4. The method according to claim 3, characterized in that Error code E of the base station i It is expressed as: in, is an indicator function; When|TOA i -TOA j |>When T is established, error code E i The value is 1, otherwise it is 0.

5. The method according to claim 1, characterized in that If the error code E of the current base station i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one, the method further includes: Determine the error code E of each base station in turn i Whether it is equal to the number of received signals N minus one, until the absolute value of the difference between the TOA value of the remaining valid base station and the TOA value of other base stations does not exceed the threshold T.

6. The method according to claim 1, characterized in that The calculation method of the time difference TDOA value between each base station is: TDOAn=TOAn-TOA1; Wherein, n=1, 2, 3, ..., N1, N1 represents the number of valid base stations, and TOAn represents the arrival time of the signal received from the nth base station.

7. The method according to claim 1 or 2, characterized in that: M＝3。 8. A TOA outlier filtering device based on a TC-OFDM positioning system, used to implement the method according to any one of claims 1 to 7, characterized in that: include: Multi-base station signal sending and receiving module, received signal recording module, signal quantity checking module, error detection module, abnormal value identification and elimination module, positioning calculation module, among which: The multi-base station signal sending and receiving module is used for multiple base stations to radiate signals and the terminal to receive multi-path signals; The received signal recording module is used to record the arrival time TOA of the signal received from each base station, and count the number N of received signals and the base station identifier corresponding to the signal; The signal quantity checking module is used to check the signal quantity and determine whether the signal quantity N is greater than or equal to the specified quantity M; The error detection module is used to calculate the time difference between the TOA value of each base station and the TOA value of other base stations in turn according to the TOA value of each base station. When the absolute value of the time difference is greater than the threshold value T, the error code E of the base station is i plus one; The abnormal value identification and elimination module is used to identify and eliminate the error code E of the current base station. i is equal to the number of received signals N minus one, then it is determined that the absolute value of the difference between the TOA value of the current base station and the TOA value of other base stations is greater than the threshold T, the current base station and the TOA value of the current base station are discarded, and the number of received signals N is reduced by one; The positioning calculation module is used to perform a final positioning calculation based on the time difference TDOA between each base station if the number of remaining valid TOA values ​​is still greater than or equal to M after filtering out TOA abnormal values.

9. The device according to claim 8, characterized in that The outlier identification and elimination module is also used for: It is determined in turn whether the error code Ei of each base station is equal to the number of received signals N minus one, until the absolute value of the difference between the TOA value of the remaining valid base station and the TOA values ​​of other base stations does not exceed the threshold T.

10. The device according to claim 8, characterized in that M＝3。

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