Phase difference estimation method, device and equipment under low signal-to-noise ratio

Abstract

The invention provides a phase difference estimation method, device and equipment under a low signal-to-noise ratio. Acquiring a first signal received by a reference antenna unit and a second signal received by a second antenna unit in the phase difference estimation system; performing signal parameter estimation and signal construction according to a main lobe signal received by a preset platform to obtain a construction signal; performing down-conversion and filtering operation on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processing signal corresponding to the first signal and a second processing signal corresponding to the second signal; performing cross-correlation operation according to the first processing signal, the second processing signal and the construction signal to obtain a first cross-correlation accumulation function of the first processing signal and the construction signal and a second cross-correlation accumulation function of the second processing signal and the construction signal; and obtaining a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function. The method has the beneficial effect of improving the phase measurement precision in a low signal-to-noise ratio environment.

Description

Technical Field

[0001] The present invention relates to the field of signal processing technology, and in particular to a phase difference estimation method, device and equipment under low signal-to-noise ratio. Background Art

[0002] Interferometer direction finding is widely used in the field of passive direction finding due to its small number of channels and high direction finding accuracy. Interferometer direction finding estimates the angle by measuring the phase difference between channels. Therefore, the measurement accuracy of the phase difference between channels is crucial to the accuracy of interferometer direction finding. Under low signal-to-noise ratio conditions, especially under low signal-to-noise ratio conditions below the receiver sensitivity, the phase difference estimation accuracy is greatly reduced, resulting in poor interferometer direction finding effect. Summary of the invention

[0003] The present invention aims to provide a phase difference estimation method, device and equipment under low signal-to-noise ratio, so as to solve the problem that the phase difference estimation accuracy is greatly reduced due to the reduction of signal-to-noise ratio.

[0004] In a first aspect, the present invention provides a phase difference estimation method under low signal-to-noise ratio, which is applied to a phase difference estimation system, wherein the phase difference estimation system includes a signal receiving model of two array antennas, and the method includes:

[0005] Acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in a phase difference estimation system;

[0006] Signal parameter estimation and signal construction are performed according to the main lobe signal received by the preset platform to obtain a constructed signal;

[0007] Performing down-conversion and filtering operations on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal;

[0008] Perform a cross-correlation operation on the first processed signal, the second processed signal and the constructed signal to obtain a first cross-correlation accumulation function of the first processed signal and the constructed signal and a second cross-correlation accumulation function of the second processed signal and the constructed signal;

[0009] A phase difference estimation value is obtained according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0010] In the present invention, obtaining a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function includes:

[0011] The estimated value of the arrival time of the initialization pulse is 0, and sliding is performed at intervals of half a frame length to obtain a plurality of first mutual correlation accumulation function values ​​and a plurality of second mutual correlation accumulation function values;

[0012] A phase difference estimation value is obtained according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power, and the accumulation gain.

[0013] In the present invention, a phase difference estimation value is obtained according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power and the accumulation gain, including:

[0014] Obtaining a first phase corresponding to the first mutual correlation accumulation function value with the largest power according to the first mutual correlation accumulation function value with the largest power and the accumulation gain;

[0015] According to the second mutual correlation accumulation function value with the largest power and the accumulation gain, a second phase corresponding to the second mutual correlation accumulation function value with the largest power is obtained;

[0016] A phase difference estimation value is obtained according to the difference between the first phase and the second phase.

[0017] In the present invention, the first cross-correlation accumulation function and the second cross-correlation accumulation function are respectively:

[0018]

[0019] in, is the first cross-correlation accumulation function, is the second cross-correlation accumulation function, For the The first processed signal at time, for The structural signal of the moment, For the The second processed signal at time instant, is the estimated value of the pulse arrival time, P is the number of pulses in the pulse train, and N is the accumulated length of each pulse repetition period.

[0020] In the present invention, signal parameter estimation and signal construction are performed according to the main lobe signal received by the preset platform to obtain a constructed signal, including:

[0021] Signal parameter estimation is performed based on the main lobe signal received by the preset platform to obtain an estimated frequency, an estimated pulse width and an estimated repetition rate;

[0022] A constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate.

[0023] In the present invention, a constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate, including:

[0024] According to the estimated pulse width and the estimated repetition rate, an initial construction signal is obtained;

[0025] The initial construction signal is down-converted and filtered according to the estimated frequency to obtain a construction signal.

[0026] In the present invention, down-conversion and filtering operations are performed on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal, including:

[0027] According to the frequency estimation value, down-converting operations are performed on the first signal and the second signal respectively to obtain a first down-converted signal and a second down-converted signal;

[0028] The first down-converted signal and the second down-converted signal are respectively input into a digital low-pass filter and extracted with K as the order to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

[0029] In the present invention, the method further comprises:

[0030] An estimated value of the azimuth of arrival is obtained according to the phase difference estimation value and the interferometer, and the interferometer is used to estimate the azimuth of arrival according to the phase difference estimation value.

[0031] In a second aspect, the present invention provides an interferometer phase difference estimation device under low signal-to-noise ratio, which is applied to a phase difference estimation system. The phase difference estimation system includes a signal receiving model of two array antennas, and the device includes:

[0032] A signal acquisition module, used to acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in a phase difference estimation system;

[0033] A signal construction module is used to estimate signal parameters and construct signals according to the main lobe signal received by the preset platform to obtain a constructed signal;

[0034] A signal processing module, used for performing down-conversion and filtering operations on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal;

[0035] A constructor module, used for performing a cross-correlation operation on the first processed signal, the second processed signal and the constructed signal to obtain a first cross-correlation accumulation function of the first processed signal and the constructed signal and a second cross-correlation accumulation function of the second processed signal and the constructed signal;

[0036] The phase difference estimation module is used to obtain a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0037] In a third aspect, the present invention provides an electronic device, comprising: a memory, a processor;

[0038] Memory stores computer-executable instructions;

[0039] The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method of the first aspect.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] The signal is reconstructed according to the parameters such as frequency, repetition rate and pulse width measured by the preset platform, and down-conversion and filtering are performed. Finally, the reconstructed signal is used to perform sliding cross-correlation accumulation with the received signals of the two channels. Within a pulse repetition period, the accumulated frame is continuously slid at half the pulse width length. When the accumulated frame and the pulse are close to coincidence, the highest accumulated gain is obtained, thereby reducing the gain loss of the noisy pulse train signal, thereby improving the phase measurement accuracy in a low signal-to-noise ratio environment, thereby improving the direction finding accuracy of the interferometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a phase difference estimation method under low signal-to-noise ratio provided in this embodiment;

[0043] Figure 2 A schematic diagram of the sliding cross-correlation processing principle provided for this embodiment;

[0044] Figure 3 A schematic diagram of the signal phase difference stability under the condition of a signal-to-noise ratio of -4dB provided in this embodiment;

[0045] Figure 4 A schematic diagram of performance comparison under signal accumulation duration provided in this embodiment;

[0046] Figure 5 A schematic diagram of a phase difference estimation device under low signal-to-noise ratio provided in this embodiment;

[0047] Figure 6 This is a schematic structural diagram of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example

[0051] Figure 1 The following is a flow chart of the phase difference estimation method under low signal-to-noise ratio provided in this embodiment. Figure 1 As shown, this embodiment proposes a phase difference estimation method under low signal-to-noise ratio, which is applied to a phase difference estimation system. The phase difference estimation system includes a signal receiving model of two array antennas. The method includes:

[0052] S101. Acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in a phase difference estimation system.

[0053] It is assumed that the signal received by the reference antenna unit is:

[0054]

[0055] Where A is the amplitude of the signal, f0 is the carrier frequency of the signal, T1 is the pulse repetition period, and rect((t-nT1) / B) represents a pulse signal with a pulse width of B and a repetition rate of T1. According to the distance d between the antennas and the signal incident angle θ, the received signal of the second antenna unit can be obtained as:

[0056] s2(t)=Arect((t+dsin(θ) / c)-nT1) / B)cos(2πf0(t+dsin(θ) / c)),

[0057] The signal s2(t) received by the second antenna unit can be further expressed as:

[0058] s2(t)=s1(t+Δt);

[0059] Where Δt = dsin(θ) / c represents the delay of adjacent antennas receiving signals, and the speed of light c = 3×10 8 .

[0060] S102: performing signal parameter estimation and signal construction according to the main lobe signal received by the preset platform to obtain a constructed signal.

[0061] Among them, the preset platform may refer to other platforms that can obtain the main lobe signal of the signal, such as a satellite communication platform, a radar system, a ground base station network, etc.

[0062] The main lobe signal may refer to a signal received in a main lobe region in an antenna pattern.

[0063] Signal parameter estimation can refer to the measurement of parameters such as frequency, pulse width and repetition rate.

[0064] Signal construction may refer to reconstructing a signal based on signal parameter estimation results.

[0065] In some implementations, the method for obtaining the constructed signal may further include:

[0066] Signal parameter estimation is performed based on the main lobe signal received by the preset platform to obtain an estimated frequency, an estimated pulse width and an estimated repetition rate;

[0067] A constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate.

[0068] Among them, since the main lobe power of the signal is relatively high, the main lobe signal is used to estimate signal parameters such as frequency, pulse width and repetition rate, so that more accurate signal parameters can be obtained. After obtaining the estimated frequency, estimated pulse width and estimated repetition rate, the initial constructed signal can be obtained based on the estimated pulse width and the estimated repetition rate; the initial constructed signal is down-converted and filtered according to the estimated frequency to obtain the constructed signal.

[0069] Specifically, obtaining the constructed signal according to the estimated frequency, the estimated pulse width and the estimated repetition rate may include:

[0070] According to the estimated pulse width and the estimated repetition rate, an initial construction signal is obtained;

[0071] The initial construction signal is down-converted and filtered according to the estimated frequency to obtain a construction signal.

[0072] Among them, the initial construction signal can be expressed as:

[0073]

[0074] in, and They are the estimated pulse width and estimated repetition rate respectively.

[0075] Then, s3(t) is down-converted and filtered by the estimated frequency to obtain the constructed signal

[0076]

[0077] S103 . Down-convert and filter the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

[0078] Down-conversion can refer to the process of moving a high-frequency signal to baseband (low frequency). Spectrum shifting is achieved by mixing the signal with an estimated frequency of the local oscillator (LO).

[0079] The filtering operation may refer to the use of filters (such as FIR / IIR) to retain the effective frequency band and suppress out-of-band noise and interference.

[0080] In some implementations, down-converting and filtering the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal may include:

[0081] According to the frequency estimation value, down-converting operations are performed on the first signal and the second signal respectively to obtain a first down-converted signal and a second down-converted signal;

[0082] The first down-converted signal and the second down-converted signal are respectively input into a digital low-pass filter and extracted with K as the order to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

[0083] Specifically, the frequency estimate can be Down-convert s1(t) and s2(t) to obtain first down-converted signals and the second down-converted signal

[0084]

[0085] Will and Input the digital low-pass filter respectively and extract with K as the order to get Corresponding and with Corresponding

[0086] S104, performing a cross-correlation operation on the first processed signal, the second processed signal, and the constructed signal to obtain a first cross-correlation accumulation function of the first processed signal and the constructed signal and a second cross-correlation accumulation function of the second processed signal and the constructed signal.

[0087] Among them, the cross-correlation operation can refer to a mathematical tool that measures the similarity of two signals and is used to analyze the degree of time shift matching of one signal in another signal.

[0088] Specifically, the first mutual correlation accumulation function and the second mutual correlation accumulation function can be expressed as:

[0089]

[0090] in, is the first cross-correlation accumulation function, is the second cross-correlation accumulation function, For the The first processed signal at time, for The structural signal of the moment, For the The second processed signal at time instant, is the estimated value of the pulse arrival time, P is the number of pulses in the pulse train, N is the accumulated length of each pulse repetition period, N = Bf s / K,f s is the sampling frequency.

[0091] S105 . Obtain a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0092] Specifically, the estimated value of the arrival time of the pulse may be initialized to 0, and the pulse may be slid at intervals of half a frame length to obtain a plurality of first mutual correlation accumulation function values ​​and a plurality of second mutual correlation accumulation function values;

[0093] A phase difference estimation value is obtained according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power, and the accumulation gain.

[0094] The accumulation gain can be obtained according to the theory of cross-correlation processing.

[0095] Furthermore, the first phase corresponding to the first mutual correlation accumulation function value with the largest power can be obtained according to the first mutual correlation accumulation function value with the largest power and the accumulation gain;

[0096] According to the second mutual correlation accumulation function value with the largest power and the accumulation gain, a second phase corresponding to the second mutual correlation accumulation function value with the largest power is obtained;

[0097] A phase difference estimation value is obtained according to the difference between the first phase and the second phase.

[0098] For example, initialization is 0, and slides at intervals of half a frame length, and we get and the corresponding f2; select the f with the largest power 1,max and f 2,max According to the theory of cross-correlation processing, the cumulative gain is 10log(N); the phases are calculated separately to obtain and And output as an estimated value of the phase difference.

[0099] After the phase difference estimate is obtained, an arrival azimuth estimate may be obtained based on the phase difference estimate and an interferometer, wherein the interferometer is used to estimate the arrival azimuth based on the phase difference estimate.

[0100] Exemplarily, when the method disclosed in this embodiment is specifically applied to perform phase measurement, corresponding parameters can be set according to actual conditions. Performing phase estimation in the manner disclosed in this embodiment includes the following steps:

[0101] Step 1: Establish a signal receiving model of two array antennas to measure the phase of the pulse train signal. The signal frequency is 4.1 GHz, the sampling frequency is 2 GHz, the pulse repetition period is 10 us, the pulse width is 1 us, and the duty cycle is 10%. The signal is incident at an azimuth angle of 45°, and the arrival time of the pulse train is unknown, which conforms to a uniform distribution between [0.5 us, 9 us].

[0102] Step 2: Since the main lobe power of the signal is relatively high, the main lobe signal obtained from other platforms is used to estimate signal parameters such as frequency, pulse width, and repetition rate.

[0103] Step 3: Down-convert and filter according to the measured signal frequency, the decimation order is 5, the frequency estimation error is a Gaussian distribution with a variance of 1 MHz, the filter bandwidth is 10 MHz, and the data rate is 20 MHz.

[0104] Step 4: According to the measured pulse width and repetition rate parameters, construct the signal s3(t) and perform sliding cross-correlation processing. Figure 2 The sliding cross-correlation processing principle diagram provided for this embodiment is as follows: Figure 2 As shown in FIG. 1 , during sliding coherent accumulation, the length of the accumulation frame is the same as the pulse width, i.e., 1 us. The sliding window length is half the pulse width, i.e., 0.5 us, which avoids the situation where the pulse is located in the center of two sliding windows.

[0105] Step 5: Output As the phase difference estimate, the algorithm performance is evaluated by the phase stability of the two channels, and the phase stability is obtained by the standard deviation of 200 Monte-Carol experiments.

[0106] Figure 3 This is a schematic diagram of the signal phase difference stability under the condition of -4dB signal-to-noise ratio provided in this embodiment. The antenna spacing is 20mm, and the signal is incident on the direction-finding antenna at an angle of 45°. The phase difference between the two channels is 205.3438°. Figure 3 The standard deviation is 14.0783°.

[0107] Figure 4 This is a schematic diagram of performance comparison under the signal accumulation time provided in this embodiment. Figure 4It can be obtained that when the signal accumulation time is 5ms, the gain of this embodiment is improved by about 4dB compared with the blind accumulation; at the same time, with the continuous increase of the accumulation time, the gain under the simulation conditions of 9ms and 10ms is increased by 0.1dB, which is consistent with the theoretical derivation.

[0108] The phase difference estimation method under low signal-to-noise ratio provided by the present invention reconstructs the signal according to parameters such as frequency, repetition rate and pulse width measured by a preset platform, and performs operations such as down-conversion and filtering. Finally, the reconstructed signal is used to perform sliding cross-correlation accumulation with the received signals of two channels respectively. Within a pulse repetition period, the accumulated frame is continuously slid with half the pulse width length. When the accumulated frame and the pulse are close to overlapping, the highest accumulated gain is obtained, thereby reducing the gain loss of the noisy pulse train signal, and further improving the phase measurement accuracy under low signal-to-noise ratio environment.

[0109] Figure 5 A schematic diagram of a phase difference estimation device under low signal-to-noise ratio provided in this embodiment is shown in FIG. Figure 5 As shown, the device 50 comprises:

[0110] A signal acquisition module 501, configured to acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in a phase difference estimation system;

[0111] A signal construction module 502 is used to estimate signal parameters and construct signals according to the main lobe signal received by the preset platform to obtain a constructed signal;

[0112] A signal processing module 503, configured to perform down-conversion and filtering operations on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal;

[0113] A constructor module 504, configured to perform a cross-correlation operation on the first processed signal, the second processed signal and the constructed signal to obtain a first cross-correlation accumulation function of the first processed signal and the constructed signal and a second cross-correlation accumulation function of the second processed signal and the constructed signal;

[0114] The phase difference estimation module 505 is used to obtain a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0115] In some implementations, the phase difference estimation module 505 is further used to:

[0116] The estimated value of the arrival time of the initialization pulse is 0, and sliding is performed at intervals of half a frame length to obtain a plurality of first mutual correlation accumulation function values ​​and a plurality of second mutual correlation accumulation function values;

[0117] A phase difference estimation value is obtained according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power, and the accumulation gain.

[0118] In some implementations, the phase difference estimation module 505 is further used to:

[0119] According to the first mutual correlation accumulation function value with the largest power and the accumulation gain, a first phase corresponding to the first mutual correlation accumulation function value with the largest power is obtained;

[0120] According to the second mutual correlation accumulation function value with the largest power and the accumulation gain, a second phase corresponding to the second mutual correlation accumulation function value with the largest power is obtained;

[0121] A phase difference estimation value is obtained according to the difference between the first phase and the second phase.

[0122] In some implementations, the signal construction module 502 is further used to:

[0123] Signal parameter estimation is performed based on the main lobe signal received by the preset platform to obtain an estimated frequency, an estimated pulse width and an estimated repetition rate;

[0124] A constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate.

[0125] In some implementations, the signal construction module 502 is further used to:

[0126] According to the estimated pulse width and the estimated repetition rate, an initial construction signal is obtained;

[0127] The initial construction signal is down-converted and filtered according to the estimated frequency to obtain a construction signal.

[0128] In some implementations, the signal processing module 503 is further used to:

[0129] According to the frequency estimation value, down-converting operations are performed on the first signal and the second signal respectively to obtain a first down-converted signal and a second down-converted signal;

[0130] The first down-converted signal and the second down-converted signal are respectively input into a digital low-pass filter and extracted with K as the order to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

[0131] The phase difference estimation device under low signal-to-noise ratio provided in this embodiment can execute the method provided in the above method embodiment, and its implementation principle and technical effect are similar, which will not be described in detail in this embodiment.

[0132] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention. Figure 6As shown, the electronic device 60 provided in this embodiment includes: at least one processor 601 and a memory 602. Optionally, the device 60 also includes a communication component 603. The processor 601, the memory 602 and the communication component 603 are connected via a bus 604.

[0133] In a specific implementation process, at least one processor 601 executes the computer execution instructions stored in the memory 602, so that at least one processor 601 executes the above method.

[0134] The specific implementation process of the processor 601 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0135] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The steps of the method disclosed in the invention may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0136] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (Non-volatile Memory, NVM), such as at least one disk memory.

[0137] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present invention is not limited to only one bus or one type of bus.

[0138] The present invention also provides a computer program product, comprising a computer program, and the computer program implements the above method when executed by a processor.

[0139] The present invention also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0140] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0141] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0142] The division of units is only a logical function division, and there may be other divisions in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0143] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0144] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0145] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0146] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0147] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A phase difference estimation method under low signal-to-noise ratio, characterized in that: Applied to a phase difference estimation system, the phase difference estimation system includes a signal receiving model of two array antennas, and the method includes: Acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in the phase difference estimation system; Signal parameter estimation and signal construction are performed according to the main lobe signal received by the preset platform to obtain a constructed signal; Performing down-conversion and filtering operations on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal; Perform a cross-correlation operation on the first processed signal, the second processed signal and the constructed signal to obtain a first cross-correlation accumulation function between the first processed signal and the constructed signal and a second cross-correlation accumulation function between the second processed signal and the constructed signal; A phase difference estimation value is obtained according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

2. The phase difference estimation method under low signal-to-noise ratio according to claim 1, characterized in that: Obtaining a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function, comprising: The estimated value of the arrival time of the initialization pulse is 0, and sliding is performed at intervals of half a frame length to obtain a plurality of first mutual correlation accumulation function values ​​and a plurality of second mutual correlation accumulation function values; A phase difference estimation value is obtained according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power, and the accumulation gain.

3. The phase difference estimation method under low signal-to-noise ratio according to claim 2, characterized in that: The step of obtaining a phase difference estimation value according to the first mutual correlation accumulation function value with the largest power, the second mutual correlation accumulation function value with the largest power and the accumulation gain comprises: Obtaining a first phase corresponding to the first mutual correlation accumulation function value with the maximum power according to the first mutual correlation accumulation function value with the maximum power and the accumulation gain; Obtaining a second phase corresponding to the second mutual correlation accumulation function value with the maximum power according to the second mutual correlation accumulation function value with the maximum power and the accumulation gain; A phase difference estimation value is obtained according to a difference between the first phase and the second phase.

4. The phase difference estimation method under low signal-to-noise ratio according to any one of claims 1 to 3, characterized in that: The first cross-correlation accumulation function and the second cross-correlation accumulation function are respectively: in, is the first cross-correlation accumulation function, is the second cross-correlation accumulation function, For the The first processed signal at time, for The structural signal of the moment, For the The second processed signal at time instant, is the estimated value of the pulse arrival time, P is the number of pulses in the pulse train, and N is the accumulated length of each pulse repetition period.

5. The phase difference estimation method under low signal-to-noise ratio according to any one of claims 1 to 3, characterized in that: The signal parameter estimation and signal construction are performed according to the main lobe signal received by the preset platform to obtain the constructed signal, including: Signal parameter estimation is performed based on the main lobe signal received by the preset platform to obtain an estimated frequency, an estimated pulse width and an estimated repetition rate; A constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate.

6. The phase difference estimation method under low signal-to-noise ratio according to claim 5, characterized in that: The step of obtaining a constructed signal according to the estimated frequency, the estimated pulse width and the estimated repetition rate comprises: Obtaining an initial construction signal according to the estimated pulse width and the estimated repetition rate; Down-converting and filtering operations are performed on the initial construction signal according to the estimated frequency to obtain a construction signal.

7. The phase difference estimation method under low signal-to-noise ratio according to any one of claims 1 to 3, characterized in that: The down-converting and filtering operations are performed on the first signal and the second signal according to the estimated frequency of the main lobe signal to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal, comprising: According to the frequency estimation value, down-converting the first signal and the second signal respectively to obtain a first down-converted signal and a second down-converted signal; The first down-converted signal and the second down-converted signal are respectively input into a digital low-pass filter and extracted with K as an order to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

8. The phase difference estimation method under low signal-to-noise ratio according to claim 1, characterized in that: The method further comprises: An estimated value of an azimuth of arrival is obtained according to the phase difference estimated value and an interferometer, and the interferometer is used to estimate the azimuth of arrival according to the phase difference estimated value.

9. A phase difference estimation device under low signal-to-noise ratio, characterized in that: Applied to a phase difference estimation system, the phase difference estimation system includes a signal receiving model of two array antennas, and the device includes: A signal acquisition module, used to acquire a first signal received by a reference antenna unit and a second signal received by a second antenna unit in the phase difference estimation system; A signal construction module is used to estimate signal parameters and construct signals according to the main lobe signal received by the preset platform to obtain a constructed signal; a signal processing module, configured to perform down-conversion and filtering operations on the first signal and the second signal according to the estimated frequency of the main lobe signal, so as to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal; A constructor module, configured to perform a cross-correlation operation on the first processed signal, the second processed signal and the constructed signal to obtain a first cross-correlation accumulation function between the first processed signal and the constructed signal and a second cross-correlation accumulation function between the second processed signal and the constructed signal; A phase difference estimation module is used to obtain a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

10. An electronic device, characterized in that: include: Memory, processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

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