A method and system for calculating correlation peaks of long-code bidirectional time-frequency comparison signals

Abstract

The application discloses a long-code bidirectional time-frequency comparison signal correlation peak calculation method and system, relates to the field of high-precision time synchronization on the ground, between the ground and the satellite and between the satellites, and aims at solving the problem that the traditional NCO interpolation method cannot determine the correlation peak position of a signal with a code length greater than 32768 and less than 65536 points and cannot capture the signal. The method comprises the following steps: acquiring bidirectional time-frequency comparison signal data and local code template data with a preset length, zero-pads the signal data and the code template data to a target length; performs fast Fourier transform on the zero-padded data, multiplies the transformed data by the conjugate, performs inverse fast Fourier transform on the multiplied result, and obtains result data; according to the position coordinates of two correlation peaks in the result data, divides the result data into two pieces of data containing a large correlation peak and a small correlation peak, zero-pads the two pieces of data to the preset length, and superimposes the two pieces of data to obtain the data correlation peak position and amplitude. The method realizes the determination of the peak value and amplitude of the preset length data signal and has strong practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-precision time synchronization on the ground, between the ground and the satellite, and between the satellites, and particularly relates to a method and system for calculating the correlation peak of a long-code bidirectional time-frequency comparison signal with a code length greater than 32768 points and less than 65536 points. BACKGROUND

[0002] Bidirectional time comparison is currently the internationally recognized highest-precision time comparison method, and is widely used in international high-precision time-frequency value remote comparison. It plays an irreplaceable role in time-frequency value transmission and traceability methods. Bidirectional time comparison uses signal spread spectrum modulation technology to perform high-precision spread spectrum modulation on the timing signal correlation information, transmits the signal through a satellite, microwave, or optical fiber link, and performs fast acquisition, precise tracking, and accurate calculation on the comparison signal at a remote comparison station to obtain the signal propagation time delay. By exchanging the propagation time delay data, the time difference information between the comparison stations can be accurately obtained, and the nanosecond-level time synchronization level can be achieved. Bidirectional method is widely used in satellite navigation, deep space exploration, and unmanned vehicle formation, and many other fields.

[0003] Currently, the bidirectional time-frequency comparison signal uses a periodic code spread spectrum system. The code length of the spread spectrum code determines the size of the signal spread spectrum gain. The longer the code length, the greater the spread spectrum gain, and the stronger the signal anti-interference ability. Therefore, when designing the bidirectional time-frequency comparison signal, a long enough code is used. At the same time, the acquisition of the bidirectional time-frequency comparison signal generally uses FFT fast acquisition by logic devices, and the number of points that can be calculated by the logic device is 2n(n=5-16), that is, the maximum FFT point number is 65536 points. This limits the code length of the spread spectrum code to be less than 65536 points. Once it is greater than 65536 points, a single FFT cannot completely process the code, and complex FFT splicing algorithms involving multiple data disassembly and complex FFT splicing algorithms are required, which has high implementation complexity and is very complex to process. Therefore, the design of the bidirectional time-frequency code length is generally as long as possible and less than 65536 points. For the bidirectional signal with a code length less than 32768 points, the traditional method is to use NCO (numerical controlled oscillator) to interpolate the collected signal and the local template original code, so that the length of the interpolated signal and the local template code is 65536 points, and then the cyclic correlation operation of the signal and the local template code is performed to determine the correlation peak and complete the signal acquisition operation. However, for the signal with a code length greater than 32768 points and less than 65536 points, due to the Nyquist sampling theorem, the traditional NCO interpolation method cannot interpolate the signal with this code length and the local template code to 65536 points, so the subsequent FFT operation cannot be performed, and the correlation peak position cannot be determined, and the signal cannot be captured. SUMMARY

[0004] The application aims to provide a long code bidirectional time-frequency comparison signal correlation peak calculation method and system, which is used to solve the problem that due to the Nyquist sampling theorem, the traditional NCO (numerical control oscillator) interpolation method can no longer interpolate the code length signal and the local template code to 65536 points, and cannot perform subsequent FFT operation, and further cannot determine the correlation peak position, and cannot realize the capture of the signal.

[0005] In order to achieve the above-mentioned purpose, the application provides the following technical scheme:

[0006] The application provides a long code bidirectional time-frequency comparison signal correlation peak calculation method, which comprises the following steps:

[0007] Step S10: collecting bidirectional time-frequency comparison signal data of a preset length M, reading a local code template of the preset length M in real time, performing a zero padding operation on the collected signal data and the read code template data, and supplementing 0 data of a length N to a target length;

[0008] Step S20: performing fast Fourier transform on the signal data and the code template data respectively, performing conjugate multiplication on the transformed data, performing inverse fast Fourier transform on the multiplied result, and obtaining result data;

[0009] Step S30: determining the position coordinates of the two correlation peaks in the result data, dividing the result data into two data segments containing large and small correlation peaks respectively according to the position coordinates of the two correlation peaks, zero padding the two divided data segments to the preset length M, the position coordinates of the correlation peaks in the two zero-padded data segments being the same, and superimposing the two data segments to obtain the data correlation peak position and amplitude.

[0010] Among them:

[0011] The preset length is 32768

[0012] Compared with the prior art, the method for calculating the correlation peak of the long-code two-way time-frequency comparison signal provided by the application comprises the following steps: zero-padded operation is performed on the collected signal data and the read code template data, and the signal data and the code template data are supplemented to a length of 65536; fast Fourier transform is performed on the zero-padded signal data and the zero-padded code template data; the conjugate of the transformed signal data is multiplied by the conjugate of the transformed code template data; fast inverse Fourier transform is performed on the multiplication result; the result data is obtained; and the result data is segmented, the zero padding and the correlation peak power superposition are utilized, and the position and the amplitude of the correlation peak of the long-code two-way time-frequency comparison signal are determined without losing the correlation peak power. The method effectively and accurately calculates the position and the amplitude of the correlation peak of the long-code two-way time-frequency comparison signal, realizes the capture of the signal, and has strong applicability.

[0013] The application further provides a system for calculating the correlation peak of a long-code two-way time-frequency comparison signal, comprising:

[0014] a data acquisition device which collects two-way time-frequency comparison signal data of a preset length M, reads a local code template of the preset length M in real time, performs zero-padded operation on the collected signal data and the read code template data, and supplements 0 data of a length N to a target length;

[0015] a data conversion device which respectively performs fast Fourier transform on the signal data and the code template data, performs conjugate multiplication on the transformed data, performs fast inverse Fourier transform on the multiplied result, and obtains result data;

[0016] a data processing device which determines the position coordinates of two correlation peaks in the result data, segments the result data into two pieces of data containing a large correlation peak and a small correlation peak according to the position coordinates of the two correlation peaks, performs zero padding on the two pieces of segmented data to a preset length M, and performs superposition on the two pieces of zero-padded data to obtain the position and the amplitude of the data correlation peak.

[0017] wherein:

[0018] the preset length is 32768 < M < 65536, the target length is 65536, and the supplement length N = 65536 - M.

[0019] Compared with the prior art, the system for calculating the correlation peak of the long-code two-way time-frequency comparison signal provided by the application has the same beneficial effects as the method for calculating the correlation peak of the long-code two-way time-frequency comparison signal, and details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0021] Figure 1 A schematic flow chart of the method for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0022] Figure 2 A schematic structural diagram of the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0023] Figure 3 A zero-filling diagram of the collected signal in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0024] Figure 4 A zero-filling diagram of the local code template in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0025] Figure 5 A diagram of the correlation peak when k≤M / 2 in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0026] Figure 6 A diagram of the splitting and zero-filling operation on the two parts of data in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0027] Figure 7 A diagram of the correlation peak after power superposition when k≤M / 2 in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0028] Figure 8 A diagram of the correlation peak when k≥M / 2 in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0029] Figure 9 A diagram of the splitting and zero-filling operation on the two parts of data in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application;

[0030] Figure 10 A diagram of the correlation peak after power superposition when k≥M / 2 in the system for calculating the correlation peak of the long-code bidirectional time-frequency comparison signal in the embodiment of the application. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, further detailed description of the present application is made below in combination with the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited. The meaning of "several" is one or more, unless otherwise explicitly specified and limited.

[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0035] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] For details Figure 1 The long-code bidirectional time-frequency comparison signal correlation peak calculation method provided by the embodiment of the present application includes the following steps:

[0037] Step S10: Collecting bidirectional time-frequency comparison signal data of a preset length M, reading a local code template of a preset length M in real time, performing a zero padding operation on the collected signal data and the read code template data, and supplementing 0 data of a length N to the target length;

[0038] Step S20: Fast Fourier transform is performed on the signal data and the code template data respectively, the transformed data is multiplied by conjugate, and the multiplied result is inverse fast Fourier transformed to obtain result data;

[0039] Step S30: The position coordinates of the two correlation peaks in the result data are determined, the result data is divided into two data segments containing the large correlation peak and the small correlation peak respectively according to the position coordinates of the two correlation peaks, the two divided data segments are zero-padded to a preset length M, the position coordinates of the correlation peaks in the two zero-padded data segments are the same, and the two data segments are superimposed to obtain the data correlation peak position and amplitude.

[0040] Wherein:

[0041] The preset length is 32768 < M < 65536, the target length is 65536, and the supplement length N = 65536 - M.

[0042] The specific implementation steps are as follows:

[0043] First step: zero padding of the collected signal

[0044] The collected signal is collected by ADC, assuming that the length of the collected signal is M, and 32768 < M < 65536, the data is zero-padded, that is, 0 is added at the end of the collected data with a length of N = 65536 - M, and 65536-point signal data for final FFT operation is obtained. As shown in Figure 3 .

[0045] Second step: zero padding of the local code template

[0046] The local code template stored in the local is read in real time, the length of the read local code template is M, and 32768 < M < 65536, the data is zero-padded, that is, 0 is added at the end of the read code template data with a length of N = 65536 - M, and 65536-point code template data for final FFT operation is obtained. As shown in Figure 4 .

[0047] Third step: FFT and IFFT operation

[0048] The 65536-point FFT operation is performed on the collected signal data zero-padded in the first step using a logic device to obtain 65536-point data a, and the 65536-point FFT operation is performed on the local template code data zero-padded in the second step to obtain 65536-point data b, and then the 65536-point IFFT is performed on the result of the conjugate multiplication of a and b to obtain 65536-point data c.

[0049] Fourth step: correlation peak position and amplitude determination

[0050] Find the position of the maximum value of the correlation peak from the data c obtained in the third step, and set the corresponding data index as k (1≤k≤65536).

[0051] When k≤M / 2, the correlation peak is as shown in Figure 5 , where there is a large and a small correlation peak at coordinates k and k+N, and the amplitude of the correlation peak at coordinate k is p, and the amplitude of the correlation peak at coordinate k+N is q.

[0052] First step: data splitting and zero padding

[0053] The data c is divided into two parts, the first part of data is the data with coordinates 1-k+N-1, and the second part of data is the data with coordinates k+N-65536. The first part of data is padded with M-k-N+1 zeros at the end to a length of M, and the second part is padded with k-1 zeros at the front to a length of M. As shown in Figure 6 .

[0054] Second step: power superposition

[0055] The two groups of zero-padded data in the previous step are superimposed to obtain the final data correlation peak position and amplitude, as shown in Figure 7 . The maximum value of the correlation peak is k, and the maximum peak value is p+q.

[0056] When k>M / 2, the correlation peak is as shown in Figure 8 , where there is a small and a small correlation peak at coordinates k-N and k, and the amplitude of the correlation peak at coordinate k is p, and the amplitude of the correlation peak at coordinate k-N is q.

[0057] First step: data splitting and zero padding

[0058] The data c is divided into two parts, the first part of data is the data with coordinates 1-k-N, and the second part of data is the data with coordinates k-N+1-65536. The first part of data is padded with M-k+N zeros at the end to a length of M, and the second part is padded with k-2N zeros at the front to a length of M. As shown in Figure 9 .

[0059] Second step: power superposition

[0060] The two groups of zero-padded data in the previous step are superimposed to obtain the final data correlation peak position and amplitude, as shown in Figure 10 . The maximum value of the correlation peak is k-N, and the maximum peak value is p+q.

[0061] The above method is suitable for the case of FFT fast capture using a logic device. Since the logic device calculates the FFT point number as a fixed 2n (n=5-16), the calculation output point number is the same as the input point number, i.e. 2n (n=5-16), and the collected data point number cannot be exactly 2n (n=5-16), the collected point number is related to the system sampling rate and the local template code period, and generally the FFT point number is selected as the minimum 2n point number capable of covering the collected point number, and in this case, the number of zeros to be supplemented is relatively small, thereby reducing the hardware FFT calculation amount and logic resources.

[0062] Compared with the prior art, in the long-code bidirectional time-frequency comparison signal correlation peak calculation method provided by the application, the signal data and the code template data are supplemented to a length of 65536 through zero padding operation on the collected signal data and the read code template data, the conjugate of the transformed signal data and the code template data is multiplied through fast Fourier transform on the zero-padded signal data and the code template data, the result data is obtained through fast Fourier inverse transform on the multiplication result, and the position and amplitude of the correlation peak of the bidirectional time-frequency comparison signal code length greater than 32768 and less than 65536 point period spread spectrum signals are determined through segmentation of the result data and power superposition of the correlation peak without loss of the correlation peak power. The above calculation method effectively and accurately calculates the position and amplitude of the correlation peak of the bidirectional time-frequency comparison signal code length greater than 32768 and less than 65536 point period spread spectrum signals, realizes the capture of the signal, and has strong applicability.

[0063] As an implementation manner, the bidirectional time-frequency comparison signal data of a preset length M is collected, the local code template of the preset length M is read in real time, and zero padding operation is performed on the collected signal data and the read code template data to supplement 0 data of a length N to a target length; the method comprises the following steps:

[0064] The bidirectional time-frequency comparison signal is collected through an analog-to-digital converter, data of a preset length M is collected, zero padding is performed at the end of the collected data, the collected data is zero-padded to a target length, and signal data is obtained;

[0065] The local code template stored locally is read in real time, the local code template data of a preset length M is read, zero padding is performed at the end of the read local code template data, and the read local code template data is supplemented to a target length to obtain code template data.

[0066] Through acquisition of the bidirectional time-frequency comparison signal data and the local code template data of the same preset length M and zero padding operation on the signal data and the local code template data, the consistency of the lengths of the final signal data and the code template data is ensured, accurate data is provided for subsequent fast Fourier transform and a series of operations, and the processing of the bidirectional time-frequency comparison signal with a length less than 65535 is realized.

[0067] As one possible implementation method, the coordinates of the two related peaks (large and small) in the result data are determined. Based on the coordinates of the two related peaks, the result data is divided into two segments. The two segments are padded with zeros to the same length, so that the positions of the related peaks are the same in both segments. The positions and amplitudes of the related peaks are obtained by superimposing the two segments. This includes the following steps:

[0068] Set the data coordinates of the large correlation peak as k, where: 1≤k≤65536;

[0069] When k≤M / 2, the coordinates of the large correlation peak are k, the peak value of the large correlation peak is p, the coordinates of the small correlation peak are k+N, and the peak value of the small correlation peak is q. The result data is divided into two segments containing the large correlation peak and the small correlation peak respectively. Zeros are added after and before the data in the two segments respectively, and the two segments are padded to the preset length M.

[0070] The two data segments after zero padding are superimposed to obtain the data correlation peak position k and amplitude p+q;

[0071] When k>M / 2, the coordinates of the large correlation peak are k, the peak value of the large correlation peak is p, the coordinates of the small correlation peak are kN, and the peak value of the small correlation peak is q. The result data is divided into two segments containing the large correlation peak and the small correlation peak respectively. Zeros are added after and before the data in the two segments respectively, and the two segments are padded to the preset length M.

[0072] The two data segments after zero padding are superimposed to obtain the data correlation peak position kN and amplitude p+q.

[0073] By setting the data coordinates of the large correlation peak as k and comparing k with M / 2, the two different cases of large and small correlation peaks were distinguished. By dividing the result data into two segments containing both large and small correlation peaks and padding the two segments with zeros, it was ensured that the lengths of the two segments were the same after padding, and that the coordinate positions of the large and small correlation peaks were the same in both segments. When the two segments were superimposed, the amplitudes of the correlation peaks were superimposed, and the positions of the data correlation peaks were determined.

[0074] As one possible implementation, when k ≤ M / 2, the result data is divided into two segments containing a large correlation peak and a small correlation peak, respectively. Zeros are then padded after and before the data in each segment to a preset length M. This includes the following steps:

[0075] The result data is divided into a first data set containing large correlation peaks with a length of 1 to k+N-1, and a second data set containing small correlation peaks with a length of k+N to 65536.

[0076] Zero padding is performed behind the first data to supplement 0 data of the length of M-k-N+1 to the preset length M, and zero padding is performed in front of the second data to supplement 0 data of the length of k-1 to the preset length M.

[0077] When k>M / 2, the segmentation of the result data according to the above data length ensures that the large correlation peak and the small correlation peak are in different data respectively, and then the zero padding is performed behind the data containing the large correlation peak and in front of the data containing the small correlation peak, so that the lengths of the two pieces of data are the same, and the position coordinates of the large correlation peak and the small correlation peak are the same, and the determination of the position k and the amplitude p+q of the correlation peak is realized through the superposition operation of the two pieces of data.

[0078] As an implementable manner, when k>M / 2, the result data is segmented into two pieces of data containing the large correlation peak and the small correlation peak respectively, and zero padding is performed behind the data and in front of the data of the two pieces of data respectively, and the two pieces of data are supplemented to the preset length M; the method comprises the following steps:

[0079] The result data is segmented into third data containing the small correlation peak and having the length of 1-k-N, and fourth data containing the large correlation peak and having the length of k-N+1-65536;

[0080] Zero padding is performed behind the third data to supplement 0 data of the length of M-k+N to the preset length M, and zero padding is performed in front of the fourth data to supplement 0 data of the length of k-2N to the preset length M.

[0081] When k>M / 2, the segmentation of the result data according to the above data length ensures that the large correlation peak and the small correlation peak are in different data respectively, and then the zero padding is performed behind the data containing the large correlation peak and in front of the data containing the small correlation peak, so that the lengths of the two pieces of data are the same, and the position coordinates of the large correlation peak and the small correlation peak are the same, and the determination of the position k-N and the amplitude p+q of the correlation peak is realized through the superposition operation of the two pieces of data.

[0082] For details Figures 2 to 10 As shown in the figure, the application further provides a long-code bidirectional time-frequency comparison signal correlation peak calculation system, comprising:

[0083] A data acquisition device acquires bidirectional time-frequency comparison signal data of a preset length M, reads a local code template of the preset length M in real time, and performs zero padding operation on the acquired signal data and the read code template data to supplement 0 data of the length of N to a target length.

[0084] A data conversion device respectively performs fast Fourier transform on the signal data and the code template data, performs conjugate multiplication on the transformed data, and performs fast inverse Fourier transform on the multiplied result to obtain result data.

[0085] The data processing device determines the position coordinates of the two correlation peaks in the result data, divides the result data into two data segments containing the large correlation peak and the small correlation peak respectively according to the position coordinates of the two correlation peaks, pads the two divided data segments to a preset length M, makes the position coordinates of the correlation peaks in the two padded data segments the same, and superimposes the two data segments to obtain the position and amplitude of the data correlation peak.

[0086] Wherein:

[0087] The preset length is 32768 < M < 65536, the target length is 65536, and the padding length N = 65536-M.

[0088] Compared with the prior art, in the calculation method of the code bidirectional time-frequency comparison signal correlation peak provided by the application, the signal data and the code template data are padded to a length of 65536 through zero padding operation, the conjugate of the transformed signal data and the code template data is multiplied, the inverse fast Fourier transform of the multiplication result is performed, the result data is obtained, the result data is divided, the zero padding and the correlation peak power superposition are used, and the position and amplitude of the correlation peak of the bidirectional time-frequency comparison signal code length greater than 32768 and less than 65536 point period spread spectrum signal are determined without losing the correlation peak power. The above calculation method effectively and accurately calculates the position and amplitude of the correlation peak of the bidirectional time-frequency comparison signal code length greater than 32768 and less than 65536 point period spread spectrum signal, realizes the capture of the signal, and has strong applicability.

[0089] As an implementable manner, the data acquisition device comprises a data acquisition device and a data reading device:

[0090] The data acquisition device is used for acquiring the bidirectional time-frequency comparison signal through an analog-to-digital converter, acquiring data of a preset length M, padding the acquired data at the end of the acquired data, padding the acquired data to a target length, and obtaining signal data;

[0091] The data reading device is used for reading the code template stored locally in real time, reading local code template data of a preset length M, padding the read local code template data at the end of the read local code template data, padding the read local code template data to a target length, and obtaining code template data.

[0092] By acquiring the bi-directional time-frequency comparison signal data and the local code template data of the same preset length M and performing zero padding on the signal data and the local code template data, the consistency of the lengths of the final signal data and the code template data is ensured, accurate data is provided for subsequent fast Fourier transform and a series of operations, and the processing of the length less than 65535 bi-directional time-frequency comparison signal is realized.

[0093] As an implementable manner, the data processing apparatus is further configured to set the data coordinate of the large correlation peak as k, where 1≤k≤65536.

[0094] When k≤M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k+N, and the small correlation peak peak value is q; the result data is divided into two data segments containing the large correlation peak and the small correlation peak respectively, zero padding is performed at the back of the two data segments and the front of the two data segments respectively, and the two data segments are supplemented to the preset length M.

[0095] The two zero-padded data segments are superimposed to obtain the data correlation peak position k and the amplitude p+q.

[0096] When k>M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k-N, and the small correlation peak peak value is q; the result data is divided into two data segments containing the large correlation peak and the small correlation peak respectively, zero padding is performed at the back of the two data segments and the front of the two data segments respectively, and the two data segments are supplemented to the preset length M.

[0097] The two zero-padded data segments are superimposed to obtain the data correlation peak position k-N and the amplitude p+q.

[0098] By setting the data coordinate of the large correlation peak as k and comparing k with M / 2, the two different cases of the large correlation peak and the small correlation peak are distinguished; by dividing the result data into two data segments containing the large correlation peak and the small correlation peak, performing zero padding on the two divided data segments, the lengths of the two zero-padded data segments are ensured to be the same, and the coordinate positions of the large correlation peak and the small correlation peak in the two data segments are the same; when the two data segments are superimposed, the superposition of the correlation peak amplitude is realized, and the determination of the data correlation peak position is also realized.

[0099] As an implementable manner, when k≤M / 2, the data processing apparatus is configured to divide the result data into first data containing the large correlation peak and having a length of 0~k+N-1, and second data containing the small correlation peak and having a length of k+N~65536.

[0100] Zero padding is performed at the back of the first data, 0 data of a length of M-k-N+1 is supplemented to the preset length M, and zero padding is performed at the front of the second data, 0 data of a length of k-1 is supplemented to the preset length M.

[0101] When k>M / 2, by dividing the result data according to the above data length, the large correlation peak and the small correlation peak are ensured to be in different data respectively, and then by zero-padding after the data containing the large correlation peak and zero-padding in front of the data containing the small correlation peak, the lengths of the two pieces of data are ensured to be the same, and the position coordinates of the large correlation peak and the small correlation peak are ensured to be the same, and by superimposing the two pieces of data, the determination of the position k and the amplitude p+q of the correlation peak is realized.

[0102] As an implementable manner, when k>M / 2, the data processing device is used for dividing the result data into third data containing the small correlation peak and having a length of 1~k-N, and fourth data containing the large correlation peak and having a length of k-N+1~65536.

[0103] Zero-padding is performed after the third data, and 0 data of a length of M-k+N is supplemented to the preset length M, and zero-padding is performed in front of the fourth data, and 0 data of a length of k-2N is supplemented to the preset length M.

[0104] When k>M / 2, by dividing the result data according to the above data length, the large correlation peak and the small correlation peak are ensured to be in different data respectively, and then by zero-padding after the data containing the large correlation peak and zero-padding in front of the data containing the small correlation peak, the lengths of the two pieces of data are ensured to be the same, and the position coordinates of the large correlation peak and the small correlation peak are ensured to be the same, and by superimposing the two pieces of data, the determination of the position k-N and the amplitude p+q of the correlation peak is realized.

[0105] In the description of the above embodiments, the specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0106] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for calculating correlation peaks of a long code bi-directional time-frequency comparison signal, characterized in that, The method comprises the following steps: Step S10: Collecting bidirectional time-frequency comparison signal data of a preset length M, reading a local code template of the preset length M in real time, performing zero padding operation on the collected signal data and the read code template data, and supplementing 0 data of a length N to a target length; Step S20: Performing fast Fourier transform on the signal data and the code template data respectively, performing conjugate multiplication on the transformed data, and performing fast inverse Fourier transform on the multiplied result to obtain result data; Step S30: Determining the position coordinates of two correlation peaks in the result data, dividing the result data into two segments containing large and small correlation peaks respectively according to the position coordinates of the two correlation peaks, performing zero padding on the two divided segments to the preset length M, and superimposing the two zero-padded segments to obtain the data correlation peak position and amplitude; Wherein: The preset length is 32768 < M < 65536, the target length is 65536, and the supplement length N = 65536-M; The determination of the position coordinates of the two correlation peaks in the result data, the division of the result data into two segments according to the position coordinates of the two correlation peaks, the zero padding of the two divided segments to the same data length, and the superimposition of the two zero-padded segments to obtain the data correlation peak position and amplitude comprise the following steps: The data coordinate is set as k, wherein: 1 ≤ k ≤ 65536; When k ≤ M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k+N, the small correlation peak peak value is q, the result data is divided into two segments containing large and small correlation peaks respectively, and zero padding is performed at the data after and the data before the two segments respectively, and the two segments are supplemented to the preset length M; Superimpose the two zero-padded segments to obtain the data correlation peak position k and the amplitude p+q; When k > M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k-N, the small correlation peak peak value is q, the result data is divided into two segments containing large and small correlation peaks respectively, and zero padding is performed at the data after and the data before the two segments respectively, and the two segments are supplemented to the preset length M; Superimpose the two zero-padded segments to obtain the data correlation peak position k-N and the amplitude p+q.

2. The method of claim 1, wherein, The collection of bidirectional time-frequency comparison signal data of a preset length M, the reading of a local code template of the preset length M in real time, the zero padding operation on the collected signal data and the read code template data, and the supplement of 0 data of a length N to a target length comprise the following steps: Collecting bidirectional time-frequency comparison signal data through an analog-to-digital converter, collecting data of a preset length M, performing zero padding at the end of the collected data, and supplementing the collected data to a target length to obtain the signal data; The code template data stored locally is read in real time, code template data of a preset length M is read, zeros are added at the end of the read code template data, the read code template data is supplemented to a target length, and the code template data is obtained.

3. The method of claim 1, wherein, When k≤M / 2, the result data is divided into two pieces of data containing large and small correlation peaks respectively, zeros are added at the back and front of the two pieces of data respectively, and the two pieces of data are supplemented to a preset length M; The method comprises the following steps: The result data is divided into first data containing large correlation peaks and having a length of 1-k+N-1, and second data containing small correlation peaks and having a length of k+N-65536; Zeros are added after the first data, 0 data of a length of M-k-N+1 is supplemented to a preset length M, and zeros are added before the second data, 0 data of a length of k-1 is supplemented to a preset length M.

4. The method of claim 1, wherein, When k>M / 2, the result data is divided into two pieces of data containing large and small correlation peaks respectively, zeros are added at the back and front of the two pieces of data respectively, and the two pieces of data are supplemented to a preset length M; The method comprises the following steps: The result data is divided into third data containing small correlation peaks and having a length of 1-k-N, and fourth data containing large correlation peaks and having a length of k-N+1-65536; Zeros are added after the third data, 0 data of a length of M-k+N is supplemented to a preset length M, and zeros are added before the fourth data, 0 data of a length of k-2N is supplemented to a preset length M.

5. A system for computing long code bi-directional time-frequency aligned signal correlation peaks, the system comprising: The method comprises the following steps: The data acquisition device collects bidirectional time-frequency comparison signal data of a preset length M, reads a local code template of a preset length M in real time, and performs a zero padding operation on the collected signal data and the read code template data, and supplements 0 data of a length of N to a target length; The data conversion device respectively performs a fast Fourier transform on the signal data and the code template data, performs a conjugate multiplication on the transformed data, and performs a fast inverse Fourier transform on the multiplied result to obtain result data; The data processing device determines position coordinates of two correlation peaks in the result data, divides the result data into two pieces of data containing large and small correlation peaks respectively according to the position coordinates of the two correlation peaks, supplements the two pieces of data to a preset length M after zero padding, and obtains data correlation peak position and amplitude by superimposing the two pieces of data after zero padding, wherein the position coordinates of the correlation peaks in the two pieces of data are the same. The preset length is 32768 The position coordinates of the data are set as k, wherein 1≤k≤65536. ​ ​ When k≤M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k+N, the small correlation peak peak value is q, the result data is divided into two data containing the large correlation peak and the small correlation peak respectively, zero padding is performed at the data back and the data front of the two data respectively, and the two data are supplemented to the preset length M; The two zero-padded data are superimposed to obtain the data correlation peak position k and the amplitude p+q; When k>M / 2, the large correlation peak position coordinate is k, the large correlation peak peak value is p, the small correlation peak position coordinate is k-N, the small correlation peak peak value is q, the result data is divided into two data containing the large correlation peak and the small correlation peak respectively, zero padding is performed at the data back and the data front of the two data respectively, and the two data are supplemented to the preset length M; The two zero-padded data are superimposed to obtain the data correlation peak position k-N and the amplitude p+q.

6. The system for calculating long code bi-directional time-frequency aligned signal correlation peaks according to claim 5, wherein, The data acquisition device comprises a data acquisition device and a data reading device: The data acquisition device is used for collecting the bidirectional time-frequency comparison signal through an analog-digital converter, collecting data of a preset length M, zero padding at the end of the collected data, zero padding the collected data to a target length, and obtaining the signal data; The data reading device is used for reading a code template stored locally in real time, reading the local code template data of a preset length M, zero padding at the end of the read local code template data, and supplementing the read local code template data to a target length to obtain the code template data.

7. The system for calculating long code bi-directional time-frequency aligned signal correlation peaks according to claim 5, wherein, When k≤M / 2, the data processing device is used for dividing the result data into first data containing a large correlation peak and having a length of 1-k+N-1, and second data containing a small correlation peak and having a length of k+N-65536; Zero padding is performed behind the first data, 0 data of a length of M-k-N+1 is supplemented to the preset length M, and zero padding is performed in front of the second data, 0 data of a length of k-1 is supplemented to the preset length M.

8. The system for calculating long code bi-directional time-frequency aligned signal correlation peaks according to claim 5, wherein, When k>M / 2, the data processing device is used for The result data is divided into third data containing a small correlation peak and having a length of 1-k-N, and fourth data containing a large correlation peak and having a length of k-N+1-65536; Zero padding is performed behind the third data, 0 data of a length of M-k+N is supplemented to the preset length M, and zero padding is performed in front of the fourth data, 0 data of a length of k-2N is supplemented to the preset length M.

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