High-precision direction finding method and device combining microwave photon and time difference phase difference

Abstract

The application provides a high-precision direction finding method and device combining time difference and phase difference of microwave and photon, and the method comprises the following steps: obtaining a target broadband microwave signal; performing smoothing filtering on each microwave signal respectively to obtain time difference estimation values corresponding to two microwave signals; obtaining phase difference estimation values corresponding to the two microwave signals according to the relationship between the time difference and the phase difference; performing consistency correction on each microwave signal respectively to obtain time-phase calibration coefficients; obtaining time difference measurement values and phase difference measurement values through the time-phase calibration coefficients respectively; performing combined direction finding processing operation according to the time difference measurement values and the phase difference measurement values to obtain a direction finding angle; the improved time difference and phase difference combined direction finding method is innovatively provided by using the advantages of time difference direction finding and phase difference direction finding, the phase difference ambiguity is solved through time difference surface fitting interpolation, high-precision direction finding of distributed single baseline two antennas can be realized, the requirements of equipment volume, power consumption and cost are reduced, and the method has good application value.

Description

Technical Field

[0001] This invention relates to the field of electronic reconnaissance technology, and more specifically, to a high-precision direction finding method and apparatus using microwave photonic combined time-difference phase difference. Background Technology

[0002] Commonly used direction finding methods include amplitude difference method, phase difference method, and time difference method. To obtain high direction finding accuracy, the amplitude difference method requires a narrow beamwidth and a large number of beams; the phase difference method requires multiple baselines to resolve phase ambiguity, and long baselines to achieve high-precision direction finding; the time difference method requires improving the accuracy of small time difference measurements or increasing the baseline length.

[0003] Due to the low accuracy of short-baseline time difference direction finding and the ambiguity problem of long-baseline phase difference direction finding, traditional microwave technology is difficult to meet the requirements of distributed deployment and long-distance transmission of electronic equipment, and cannot achieve the high-precision direction finding requirements of distributed single-baseline two-antenna systems. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision direction finding method and device for microwave photonics combined with time difference and phase difference, which can overcome the influence of time difference and phase difference changes caused by long-distance transmission of microwave signals through optical fibers, perform real-time correction of equipment time difference and phase difference inconsistencies at the system level, and meet the stable transmission of long-distance microwave photonics.

[0005] Leveraging the advantages of time-difference and phase-difference direction finding, this paper innovatively proposes an improved time-difference and phase-difference joint direction finding method. By fitting and interpolating the time-difference surface to resolve phase-difference ambiguity, it can achieve high-precision direction finding with two antennas on a distributed single baseline, reducing the requirements for equipment size, power consumption, and cost, and has great application value.

[0006] The embodiments of the present invention are implemented as follows:

[0007] In a first aspect, embodiments of this application provide a high-precision direction finding method using microwave photonic combined time-difference phase difference, comprising the following steps:

[0008] Acquire at least two microwave signals of analog signal type;

[0009] Convert at least two analog microwave signals into at least two digital microwave signals;

[0010] For each pair of at least two microwave signals of digital signal type, smoothing filtering is performed on the two microwave signals to obtain the estimated time difference between the two microwave signals.

[0011] For each pair of at least two microwave signals of digital signal type, the estimated phase difference between the two microwave signals is determined based on the estimated time difference between the two microwave signals and the pre-defined correspondence between the estimated time difference and the estimated phase difference.

[0012] For each pair of at least two microwave signals of digital signal type, consistency correction is performed on each microwave signal to obtain the phase calibration coefficient between the two microwave signals; the estimated time difference and estimated phase difference of the two microwave signals are corrected by the phase calibration coefficient to obtain the measured time difference and measured phase difference respectively.

[0013] For each pair of at least two microwave signals of digital signal type, the direction finding angle is obtained by performing joint direction finding processing based on the time difference measurement value and phase difference measurement value of the two microwave signals.

[0014] The beneficial effects of this invention are as follows: By acquiring two analog microwave signals, converting them to digital microwave signals, and then performing smoothing and filtering, the estimated time difference between the two microwave signals is obtained. Based on the relationship between the estimated time difference and the estimated phase difference, the estimated phase difference is obtained. After performing consistency correction on the two microwave signals respectively, the obtained timing calibration coefficient is used to correct the estimated time difference and the estimated phase difference. This overcomes the influence of time difference and phase difference changes caused by long-distance transmission of microwave signals through optical fibers, thus addressing the inconsistency in time difference between devices at the overall equipment level. This invention addresses the issue of real-time correction and stable long-distance microwave photon transmission. It obtains time difference and phase difference measurements, and then performs joint direction finding processing based on these measurements to obtain the direction finding angle, thus achieving the final direction finding objective. The invention leverages the advantages of time difference and phase difference direction finding to innovate an improved time-and-phase difference joint direction finding method. This method performs joint direction finding processing based on the time difference and phase difference measurements corresponding to two microwave signals, achieving high-precision direction finding for a distributed single-baseline two-antenna system. This reduces equipment size, power consumption, and cost, and has high application value.

[0015] Based on the above technical solution, the present invention can be further improved as follows.

[0016] Furthermore, for each pair of at least two microwave signals of the digital signal type, smoothing filtering is performed on the two microwave signals to obtain an estimated time difference between the two microwave signals, including:

[0017] For each pair of at least two microwave signals of digital signal type, the two microwave signals are smoothed and filtered using the first formula to obtain the estimated time difference between the two microwave signals. The first formula is:

[0018]

[0019] Where: τ represents the estimated time difference, P represents the spectral peak of the interval search |F(m)|, i represents the number of interval interpolations of F(m)|, and F(m) represents the discrete Fourier transform operation.

[0020] The beneficial effect of adopting the above-mentioned further scheme is that the time difference estimate of the two microwave signals can be obtained through the first formula.

[0021] Furthermore, for each pair of at least two microwave signals of the digital signal type, the estimated phase difference between the two microwave signals is determined based on the estimated time difference between the two microwave signals and the preset correspondence between the estimated time difference and the estimated phase difference, including the following steps:

[0022] For each pair of at least two microwave signals of digital signal type, perform FFT transformation on the two microwave signals to obtain the transformed two microwave signals:

[0023] For each pair of at least two microwave signals of digital signal type, based on the transformed two microwave signals, the two microwave signals are multiplied by their conjugates in the frequency domain to obtain the result of the conjugate multiplication of the two microwave signals;

[0024] For each pair of at least two microwave signals of digital signal type, the estimated phase difference between the two microwave signals is obtained based on the result of multiplying the conjugates of the two microwave signals.

[0025] The beneficial effect of adopting the above-mentioned further scheme is that, based on the relationship between time difference and phase difference, the estimated value of the phase difference between the two microwave signals can be obtained, providing calculation data for subsequent processing.

[0026] Furthermore, for each pair of at least two microwave signals of the digital signal type, joint direction-finding processing is performed based on the time difference measurement and phase difference measurement values ​​corresponding to the two microwave signals to obtain the direction-finding angle, including the following steps:

[0027] For each pair of at least two microwave signals of digital signal type, based on the time difference measurement values ​​corresponding to the two microwave signals, the time difference measurement values ​​are interpolated using a surface fitting algorithm to obtain multiple difference points. Based on the multiple difference points, an upward-opening quadratic surface is determined, and a group of time difference measurement values ​​is obtained based on the quadratic surface.

[0028] Based on the second formula, a set of phase difference measurements for multiple interpolation points is determined; whereby the second formula is:

[0029]

[0030] In the formula, Δφ is the error between the theoretical value of the phase difference and the measured value of the phase difference, and Δτ is the error between the theoretical value of the time difference and the measured value of the time difference;

[0031] Based on the time difference measurement set and the similarity function, multiple sets of similarity functions are obtained;

[0032] Determine the minimum value of multiple sets of similarity functions, and the target time difference corresponding to the minimum value of multiple sets of similarity functions, where the similarity function is:

[0033]

[0034] Where γ() represents the similarity function, This represents the phase difference measurement value. This represents the theoretical phase difference value corresponding to the i-th interpolation, where i represents the number of interpolations;

[0035] Based on the target time difference and the second formula, the true fuzzy number k is obtained. 真 ;

[0036] Based on the actual fuzzy number and the phase difference angle measurement formula, the direction-finding angle is obtained. The phase difference angle measurement formula is expressed as:

[0037]

[0038] In the formula, θ represents the direction-finding angle value. denoted by , where d represents the phase difference measurement, λ represents the distance between the two distributed antenna elements, λ represents the wavelength of the microwave signal, and arcsin represents the arcsine operation.

[0039] The beneficial effects of adopting the above-mentioned further scheme are: by performing joint direction finding processing calculations on the time difference measurement value and the phase difference measurement value, the direction finding angle is obtained; in particular, when performing joint direction finding processing calculations on the time difference measurement value and the phase difference measurement value, the error between the theoretical value of the phase difference and the measured value, the error between the theoretical value of the time difference and the measured value, and the determination of the K value, the direction finding angle is finally obtained according to the phase difference angle measurement formula, thereby improving the accuracy of the direction finding angle.

[0040] In a second aspect, embodiments of this application provide a high-precision direction-finding device for microwave-photon combined time-difference and phase-difference methods, applied to any of the methods in the first aspect, including:

[0041] The receiving module is used to acquire at least two microwave signals of analog signal type;

[0042] A conversion module for converting at least two analog microwave signals into at least two digital microwave signals;

[0043] The processing module is used to perform smoothing filtering on each pair of at least two microwave signals of digital signal type to obtain the estimated time difference between the two microwave signals.

[0044] The calculation module is used to determine the estimated phase difference between two microwave signals for each pair of at least two microwave signals of digital signal type, based on the estimated time difference between the two microwave signals and the pre-defined correspondence between the estimated time difference and the estimated phase difference.

[0045] The calibration module is used to perform consistency calibration on each pair of at least two microwave signals of digital signal type to obtain the phase calibration coefficient between the two microwave signals; and to correct the estimated time difference and phase difference of the two microwave signals through the phase calibration coefficient to obtain the measured time difference and phase difference respectively.

[0046] The direction finding calculation module is used to perform joint direction finding processing calculations on each pair of at least two microwave signals of digital signal type, based on the time difference measurement value and phase difference measurement value corresponding to the two microwave signals, to obtain the direction finding angle.

[0047] Furthermore, the aforementioned calculation module includes:

[0048] The transformation submodule is used to perform FFT transformation on each pair of at least two microwave signals of digital signal type to obtain two transformed microwave signals.

[0049] The conjugate multiplication submodule is used to perform conjugate multiplication on each pair of at least two microwave signals of digital signal type in the frequency domain based on the transformed two microwave signals to obtain the result of the conjugate multiplication of the two microwave signals.

[0050] The determination submodule is used to estimate the phase difference between two microwave signals for each pair of at least two microwave signals of digital signal type, based on the result of multiplying the conjugates of the two microwave signals.

[0051] Furthermore, the aforementioned direction-finding calculation module includes:

[0052] The interpolation submodule is used to perform interpolation on the time difference measurement values ​​of at least two microwave signals of digital signal type for each pair of microwave signals, based on the time difference measurement values ​​corresponding to the two microwave signals, using a surface fitting algorithm to obtain multiple difference points, and determine an upward-opening quadratic surface based on the multiple difference points, and obtain a group of time difference measurement values ​​based on the quadratic surface.

[0053] The second formula calculation submodule is used to determine a set of phase difference measurement values ​​for multiple interpolation points based on the second formula; wherein the second formula is:

[0054]

[0055] In the formula, Δφ is the error between the theoretical value of the phase difference and the measured value of the phase difference, and Δτ is the error between the theoretical value of the time difference and the measured value of the time difference;

[0056] The similarity submodule is used to obtain multiple sets of similarity functions based on the time difference measurement value group and the similarity function;

[0057] The similarity determination submodule is used to determine the minimum value of multiple sets of similarity functions, and the target time difference corresponding to the minimum value of multiple sets of similarity functions, wherein the similarity function is:

[0058]

[0059] Where γ() represents the similarity function, This represents the phase difference measurement value. This represents the theoretical phase difference value corresponding to the i-th interpolation, where i represents the number of interpolations;

[0060] The defuzzy number submodule is used to obtain the true fuzzy number k based on the target time difference and the second formula. 真 ;

[0061] The lateral angle calculation submodule is used to obtain the direction-finding angle based on the actual fuzzy number and the phase difference angle measurement formula. The phase difference angle measurement formula is expressed as:

[0062]

[0063] In the formula, θ represents the direction-finding angle value. denoted by , where d represents the phase difference measurement, λ represents the distance between the two distributed antenna elements, λ represents the wavelength of the microwave signal, and arcsin represents the arcsine operation.

[0064] Thirdly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the methods in the first aspect.

[0065] Fourthly, embodiments of this application provide a non-transitory computer-readable storage medium that stores computer instructions that cause a computer to perform any of the methods in the first aspect. Attached Figure Description

[0066] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 This is a block diagram illustrating the principle of high-precision direction finding using combined time difference and phase difference in this embodiment of the invention.

[0068] Figure 2 This is a flowchart of the high-precision direction finding method using combined time difference and phase difference in an embodiment of the present invention;

[0069] Figure 3 This is a flowchart of the high-precision direction finding method in an embodiment of the present invention;

[0070] Figure 4 This is a connection diagram of the high-precision direction finding device in an embodiment of the present invention;

[0071] Figure 5 This is a schematic diagram of the connection of an electronic device in an embodiment of the present invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0073] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0074] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0075] Example

[0076] In a first aspect, embodiments of this application provide a high-precision direction finding method using microwave photonic combined time-difference phase difference, comprising the following steps:

[0077] S1. Acquire at least two microwave signals of analog signal type;

[0078] In acquiring microwave signals of the target bandwidth, distributed antenna array elements can be used. It should be noted that two distributed antenna array elements can be used to acquire two microwave signals of two target bandwidths.

[0079] S2. Convert at least two analog microwave signals into at least two digital microwave signals;

[0080] The conversion of two analog microwave signals into digital microwave signals can be achieved through microwave photonic transmission links. The two distributed antenna elements used to acquire the analog microwave signals are connected to the two microwave photonic transmission links. Each microwave photonic transmission link may include an optical transmitter, a composite optical cable, an optical receiver, and a high-speed ADC (analog-to-digital converter). The optical transmitter transmits the microwave photons from each channel to the composite optical cable, which then transmits them to the optical receiver. The optical receiver transmits the microwave photons from each channel to the high-speed ADC to convert each analog microwave signal into a digital microwave signal. The microwave photonic transmission link may also include an adjustable optical delay line, a photodetector, and a phase stabilization control module, which respectively control the delay of the microwave signal, convert the microwave photonics of the optical signal into microwave photonics of the electrical signal, and stabilize the microwave photonics of the electrical signal. After receiving the microwave signal output from the distributed antenna array element, it is processed by active amplification and an optical transmitter, and then sent to an optical receiver for reception and processing through a composite optical cable. Then, through phase control means such as the adjustable optical delay line, photodetector, and phase stabilization control module, the microwave signal maintains signal delay and phase stability after long-distance optical fiber transmission. Finally, the analog microwave signal is converted into a digital microwave signal through a high-speed ADC (analog-to-digital converter).

[0081] S3. For each pair of at least two microwave signals of digital signal type, perform smoothing filtering on the two microwave signals to obtain the estimated time difference between the two microwave signals.

[0082] In smoothing filtering, the generalized cross-correlation method can be used to apply a frequency domain weighting function to the signal. The generalized correlation method addresses the shortcomings of the basic correlation method, reducing and eliminating the impact of noise on correlation delay estimation. It involves first calculating the cross-power spectral density of the two signals and then performing weighting. This pre-processing of the signal, based on the basic correlation method, aims to improve the signal-to-noise ratio (SNR). Increased SNR effectively improves the accuracy of delay estimation. The steps are: processing the signal to improve the SNR, then calculating the cross-correlation function of the two signals; the peak value of the cross-correlation function represents the delay value.

[0083] Optionally, for each pair of at least two microwave signals of digital signal type, smoothing filtering is performed on the two microwave signals to obtain an estimated time difference between the two microwave signals, including:

[0084] For each pair of at least two microwave signals of digital signal type, the two microwave signals are smoothed and filtered using the first formula to obtain the estimated time difference between the two microwave signals. The first formula is:

[0085]

[0086] Where: τ represents the estimated time difference, P represents the spectral peak of the interval search |F(m)|, i represents the number of interval interpolations of |F(m)|, and F(m) represents the discrete Fourier transform operation.

[0087] S4. For each pair of at least two microwave signals of digital signal type, determine the estimated phase difference value of the two microwave signals based on the estimated time difference value of the two microwave signals and the pre-defined correspondence between the estimated time difference value and the estimated phase difference value.

[0088] Among them, the phase difference estimation value can be obtained based on the relationship between time difference and phase difference. The phase difference estimation value can be obtained by digital phase detection method. The digital phase detection method is based on the phase difference of the same signal at different sampling times to make the estimation.

[0089] Optionally, for each pair of at least two microwave signals of digital signal type, determining the estimated phase difference between the two microwave signals based on the estimated time difference between the two microwave signals and the preset correspondence between the estimated time difference and the estimated phase difference can include the following steps:

[0090] For each pair of at least two microwave signals of digital signal type, perform FFT transformation on the two microwave signals to obtain the transformed two microwave signals:

[0091] For each pair of at least two microwave signals of digital signal type, based on the transformed two microwave signals, the two microwave signals are multiplied by their conjugates in the frequency domain to obtain the result of the conjugate multiplication of the two microwave signals;

[0092] For each pair of at least two microwave signals of digital signal type, the estimated phase difference between the two microwave signals is obtained based on the result of multiplying the conjugates of the two microwave signals.

[0093] The expressions for the two microwave signals can be:

[0094]

[0095] In the formula, x1(t) and x2(t) represent two microwave signals, f represents the signal carrier frequency, and τ represents the time difference between the two signals;

[0096] Specifically, FFT transformation is performed on the two microwave signals to obtain the transformed two microwave signals:

[0097]

[0098] In the formula, X1(f) and X2(f) represent the two microwave signals after FFT transformation, f represents the signal carrier frequency, and τ represents the time difference between the two microwave signals;

[0099] Specifically, based on the transformed two microwave signals, the two microwave signals are multiplied by their conjugate in the frequency domain to obtain the result of the conjugate multiplication of the two microwave signals:

[0100] Y(f) = X1(f)·X2(f) * =X1(f)·[e -j2πfτ X1(f)] * =e j2πfτ ·[X1(f)] 2 ;

[0101] In the formula, · represents multiplication, and * represents conjugate operation;

[0102] The phase difference φ between the two microwave signals is obtained by multiplying the two signals by their conjugates.

[0103]

[0104] Where * represents the conjugate operation, Re represents the real part operation, Im represents the imaginary part operation, arctan represents the arctangent operation, f represents the signal carrier frequency, and f0 represents the signal carrier frequency value.

[0105] S5. For each pair of at least two microwave signals of digital signal type, perform consistency correction on each microwave signal to obtain the phase calibration coefficient between the two microwave signals; use the phase calibration coefficient to correct the estimated time difference and estimated phase difference of the two microwave signals to obtain the measured time difference and measured phase difference respectively.

[0106] Because microwave photonic transmission links are easily affected by external environmental factors and the performance of optical transmitters and receivers during long-distance transmission, the time difference and phase difference of microwave signals change after long-distance transmission. Therefore, each microwave signal needs to undergo consistency correction. One method for correction is using a built-in correction source. The microwave signal to be corrected is fed into the microwave photonic transmission link from the optical power divider network, sampled, encoded, and interpolated using I / Q to obtain the corrected signal. The inter-channel timing calibration coefficients are calculated and stored as samples. The estimated time difference τ and phase difference φ are corrected using the timing calibration coefficients to obtain the measured time difference τ and phase difference φ, respectively. Alternatively, manual correction can be used. This can involve: first, monitoring changes in environmental conditions in real time, measuring the inconsistencies in time difference and phase difference between each receiving channel and the reference channel (i.e., the differences between them), and then compensating for these inconsistencies through manual or automatic control of environmental conditions.

[0107] S6. For each pair of at least two microwave signals of digital signal type, perform joint direction finding processing based on the time difference measurement value and phase difference measurement value corresponding to the two microwave signals to obtain the direction finding angle.

[0108] Since the measurement results of time difference and phase difference always contain a certain degree of error—that is, the measured value of time difference τ and the measured value of phase difference φ have certain errors—an improved method of resolving phase difference ambiguity by fitting and interpolating the time difference surface can achieve high-precision joint time difference and phase difference direction finding with two antennas on a single baseline. (See also...) Figure 2 The distributed antenna receives the signal, i.e., acquires the microwave signal, transmits it to the microwave photonic transmission and receiving channel, and performs ADC sampling and processing. This involves converting two analog microwave signals into digital microwave signals via the microwave photonic transmission link. Time difference and phase difference measurements are then performed separately, and time difference and phase difference consistency corrections are applied to obtain the time difference measurement value τ and phase difference measurement value φ. Finally, direction finding is achieved through joint time difference and phase difference measurements, and the resulting angle, i.e., the direction-finding angle θ, is the angle between the source direction of the microwave signal and the normal. See [link to documentation]. Figure 1The direction finding angle θ is the angle between the source direction of the microwave signal and the normal. Through electro-optic conversion, it can be transmitted through a composite cable. After photoelectric conversion, it is transmitted to the receiving channel. The receiving channel processes the photoelectric converted signal and the microwave signal through the microwave photonic transmission link. Finally, after time difference measurement, phase difference measurement and angle conversion, the time difference and phase difference joint direction finding is performed, thereby outputting the direction finding angle θ.

[0109] Optionally, for each pair of at least two microwave signals of the digital signal type, the direction-finding angle is obtained by performing joint direction-finding processing based on the time difference measurement and phase difference measurement values ​​corresponding to the two microwave signals, including the following steps:

[0110] For each pair of at least two microwave signals of digital signal type, based on the time difference measurement values ​​corresponding to the two microwave signals, the time difference measurement values ​​are interpolated using a surface fitting algorithm to obtain multiple difference points. Based on the multiple difference points, an upward-opening quadratic surface is determined, and a group of time difference measurement values ​​is obtained based on the quadratic surface.

[0111] Among them, the theoretical value of phase difference The error between the measured phase difference value φ and the theoretical time difference value can be Δφ; The error between the measured time difference value τ and the actual time difference value τ can be Δτ;

[0112] Then, based on the second formula, a set of phase difference measurements for multiple interpolation points is determined. The second formula represents the relationship between phase difference and time difference; specifically:

[0113]

[0114] In the formula, Δφ is the error between the theoretical value of the phase difference and the measured value of the phase difference, and Δτ is the error between the theoretical value of the time difference and the measured value of the time difference;

[0115] Specifically, based on the time difference measurement value τ, a surface fitting algorithm is used to analyze the time difference measurement value. Interpolation is performed, and an upward-opening quadratic surface is fitted at 8 points to obtain the time difference measurement set:

[0116]

[0117] According to the second formula, the corresponding interpolated phase difference measurement values ​​are obtained as follows: The specific calculation formula is as follows:

[0118]

[0119] In the formula, mod() represents the modulo operation;

[0120] Based on the time difference measurement set and the similarity function, multiple sets of similarity functions are obtained;

[0121] Determine the minimum value of multiple sets of similarity functions, and the target time difference corresponding to the minimum value of multiple sets of similarity functions. That is, obtain multiple sets of similarity functions γ based on the time difference measurement set and the similarity function. i Find multiple sets of similarity functions γ i The minimum value, and multiple sets of similar functions γ i The minimum value corresponds to the target time difference. The similarity function is:

[0122]

[0123] Where γ() represents the similarity function, This represents the phase difference measurement value. This represents the theoretical phase difference value corresponding to the i-th interpolation, where i represents the number of interpolations;

[0124] Based on the target time difference and the second formula, we obtain k. 真 k 真 The true fuzzy number k value;

[0125] Based on the actual fuzzy number and the phase difference angle measurement formula, the direction-finding angle is obtained. The phase difference angle measurement formula is expressed as:

[0126]

[0127] In the formula, θ represents the direction-finding angle value. denoted by , where d represents the phase difference measurement, λ represents the distance between the two distributed antenna elements, λ represents the wavelength of the microwave signal, and arcsin represents the arcsine operation.

[0128] In a second aspect, embodiments of this application provide a high-precision direction-finding device for microwave-photon combined time-difference and phase-difference methods, applied to any of the methods in the first aspect, including:

[0129] The receiving module is used to acquire at least two microwave signals of analog signal type;

[0130] A conversion module for converting at least two analog microwave signals into at least two digital microwave signals;

[0131] The processing module is used to perform smoothing filtering on each pair of at least two microwave signals of digital signal type to obtain the estimated time difference between the two microwave signals.

[0132] The calculation module is used to determine the estimated phase difference between two microwave signals for each pair of at least two microwave signals of digital signal type, based on the estimated time difference between the two microwave signals and the pre-defined correspondence between the estimated time difference and the estimated phase difference.

[0133] The calibration module is used to perform consistency calibration on each pair of at least two microwave signals of digital signal type to obtain the phase calibration coefficient between the two microwave signals; and to correct the estimated time difference and phase difference of the two microwave signals through the phase calibration coefficient to obtain the measured time difference and phase difference respectively.

[0134] The direction finding calculation module is used to perform joint direction finding processing calculations on each pair of at least two microwave signals of digital signal type, based on the time difference measurement value and phase difference measurement value corresponding to the two microwave signals, to obtain the direction finding angle.

[0135] Optionally, the above calculation module includes:

[0136] The transformation submodule is used to perform FFT transformation on each pair of at least two microwave signals of digital signal type to obtain two transformed microwave signals.

[0137] The conjugate multiplication submodule is used to perform conjugate multiplication on each pair of at least two microwave signals of digital signal type in the frequency domain based on the transformed two microwave signals to obtain the result of the conjugate multiplication of the two microwave signals.

[0138] The determination submodule is used to estimate the phase difference between two microwave signals for each pair of at least two microwave signals of digital signal type, based on the result of multiplying the conjugates of the two microwave signals.

[0139] Optionally, the direction finding calculation module mentioned above includes:

[0140] The interpolation submodule is used to perform interpolation on the time difference measurement values ​​of at least two microwave signals of digital signal type for each pair of microwave signals, based on the time difference measurement values ​​corresponding to the two microwave signals, using a surface fitting algorithm to obtain multiple difference points, and determine an upward-opening quadratic surface based on the multiple difference points, and obtain a group of time difference measurement values ​​based on the quadratic surface.

[0141] The second formula calculation submodule is used to determine a set of phase difference measurement values ​​for multiple interpolation points based on the second formula; wherein the second formula is:

[0142]

[0143] In the formula, Δφ is the error between the theoretical value of the phase difference and the measured value of the phase difference, and Δτ is the error between the theoretical value of the time difference and the measured value of the time difference;

[0144] The similarity submodule is used to obtain multiple sets of similarity functions based on the time difference measurement value group and the similarity function;

[0145] The similarity determination submodule is used to determine the minimum value of multiple sets of similarity functions, and the target time difference corresponding to the minimum value of multiple sets of similarity functions, wherein the similarity function is:

[0146]

[0147] Where γ() represents the similarity function, This represents the phase difference measurement value. This represents the theoretical phase difference value corresponding to the i-th interpolation, where i represents the number of interpolations;

[0148] The defuzzy number submodule is used to obtain k based on the target time difference and the second formula. 真 k 真 The true fuzzy number k value;

[0149] The lateral angle calculation submodule is used to obtain the direction-finding angle based on the actual fuzzy number and the phase difference angle measurement formula. The phase difference angle measurement formula is expressed as:

[0150]

[0151] In the formula, θ represents the direction-finding angle value. denoted by , where d represents the phase difference measurement, λ represents the distance between the two distributed antenna elements, λ represents the wavelength of the microwave signal, and arcsin represents the arcsine operation.

[0152] Thirdly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the methods in the first aspect.

[0153] Fourthly, embodiments of this application provide a non-transitory computer-readable storage medium that stores computer instructions that cause a computer to perform any of the methods in the first aspect.

[0154] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-precision direction finding method using microwave photonic combined time-difference and phase-difference methods, characterized in that, Includes the following steps: Acquire at least two microwave signals of analog signal type; Convert at least two microwave signals of the analog signal type into at least two microwave signals of the digital signal type; For each pair of at least two microwave signals of the digital signal type, the two microwave signals are smoothed and filtered to obtain the estimated time difference between the two microwave signals. For each pair of at least two microwave signals of the digital signal type, the estimated phase difference value of the two microwave signals is determined based on the estimated time difference value of the two microwave signals and the correspondence between the preset estimated time difference value and the estimated phase difference value. For each pair of at least two microwave signals of the digital signal type, consistency correction is performed on each microwave signal to obtain a phase calibration coefficient between the two microwave signals; the estimated time difference and estimated phase difference of the two microwave signals are corrected by the phase calibration coefficient to obtain the measured time difference and measured phase difference, respectively. For each pair of at least two microwave signals of the digital signal type, a joint direction finding operation is performed based on the time difference measurement value and phase difference measurement value corresponding to the two microwave signals to obtain the direction finding angle.

2. The high-precision direction finding method based on microwave photon combined time-difference phase difference according to claim 1, characterized in that, For each pair of at least two microwave signals of the digital signal type, determining the estimated phase difference between the two microwave signals based on the estimated time difference between the two microwave signals and the preset correspondence between the estimated time difference and the estimated phase difference includes the following steps: For each pair of at least two microwave signals of the digital signal type, perform an FFT transform on the two microwave signals to obtain the transformed two microwave signals: For each pair of at least two microwave signals of the digital signal type, based on the transformed two microwave signals, the two microwave signals are multiplied by their conjugates in the frequency domain to obtain the result of the multiplication of the two microwave signals by their conjugates. For each pair of at least two microwave signals of the digital signal type, the estimated phase difference between the two microwave signals is obtained based on the result of multiplying the conjugates of the two microwave signals.

3. A high-precision direction finding device combining microwave photonic time-difference and phase difference, applied to the method according to any one of claims 1-2, characterized in that, include: The receiving module is used to acquire at least two microwave signals of analog signal type; A conversion module is used to convert at least two microwave signals of the analog signal type into at least two microwave signals of the digital signal type; The processing module is used to perform smoothing filtering on each pair of at least two microwave signals of the digital signal type to obtain an estimated time difference value corresponding to the two microwave signals. The calculation module is used to determine the estimated phase difference value of each pair of microwave signals in at least two microwave signals of the digital signal type, based on the estimated time difference value of the two microwave signals and the correspondence between the preset estimated time difference value and the estimated phase difference value. The calibration module is used to perform consistency calibration on each pair of at least two microwave signals of the digital signal type to obtain a phase calibration coefficient between the two microwave signals; and to correct the estimated time difference and estimated phase difference of the two microwave signals using the phase calibration coefficient to obtain the measured time difference and measured phase difference, respectively. The direction finding calculation module is used to perform joint direction finding processing calculations on each pair of at least two microwave signals of the digital signal type, based on the time difference measurement value and phase difference measurement value corresponding to the two microwave signals, to obtain the direction finding angle.

4. A high-precision direction finding device for microwave photonic combined time-difference and phase-difference as described in claim 3, characterized in that, The computing module includes: The transformation submodule is used to perform FFT transformation on each pair of at least two microwave signals of the digital signal type to obtain the transformed two microwave signals. The conjugate multiplication submodule is used to perform conjugate multiplication on each pair of at least two microwave signals of the digital signal type in the frequency domain based on the transformed two microwave signals to obtain the result of the conjugate multiplication of the two microwave signals. The determination submodule is used to determine the estimated phase difference between two microwave signals for each pair of at least two microwave signals of the digital signal type, based on the result of multiplying the conjugates of the two microwave signals.

5. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method of any one of claims 1-2.

6. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the method described in any one of claims 1-2.

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