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

Abstract

The application provides a phase difference estimation method, device and equipment under low signal-to-noise ratio. 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 are acquired; signal parameter estimation and signal construction are performed according to a main lobe signal received by a preset platform to obtain a constructed signal; the first signal and the second signal are down-converted and filtered according to an 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; cross-correlation operation is performed according to the first processing signal, the second processing signal and the constructed signal to obtain a first cross-correlation accumulation function of the first processing signal and the constructed signal and a second cross-correlation accumulation function of the second processing signal and the constructed signal; and a phase difference estimation value is obtained according to the first cross-correlation accumulation function and the second cross-correlation accumulation function. The application has the beneficial effect of improving phase measurement precision under low signal-to-noise ratio.

Description

TECHNICAL FIELD

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

[0002] Interferometer direction finding is widely used in passive direction finding field due to less number of channels and high direction finding accuracy. Interferometer direction finding is to estimate angle by measuring phase difference between channels, so the measurement accuracy of phase difference between channels is crucial to interferometer direction finding accuracy. Under low signal-to-noise ratio, especially under low signal-to-noise ratio below receiver sensitivity, the phase difference estimation accuracy is greatly reduced, which makes the interferometer direction finding effect poor. SUMMARY

[0003] The present application aims to provide a phase difference estimation method, device and equipment under low signal-to-noise ratio, to solve the problem of greatly reduced phase difference estimation accuracy caused by reduced signal-to-noise ratio.

[0004] In the first aspect, the present application provides a phase difference estimation method under low signal-to-noise ratio, applied to a phase difference estimation system including a signal receiving model of two array antennas, the method comprising:

[0005] Obtaining 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;

[0006] Performing signal parameter estimation and signal construction according to a main lobe signal received by a 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 processing signal corresponding to the first signal and a second processing signal corresponding to the second signal;

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

[0009] Obtaining a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0010] In the present application, the phase difference estimation value is obtained according to the first cross-correlation accumulation function and the second cross-correlation accumulation function, comprising:

[0011] Initializing the arrival time estimation value of the pulse to 0, and performing sliding with half frame length as interval to obtain a plurality of first cross-correlation accumulation function values and a plurality of second cross-correlation accumulation function values respectively;

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

[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 t, 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 based on the main lobe signal received by the preset platform to obtain a constructed signal, including:

[0021] Signal parameters are estimated based on the main lobe signal received by the preset platform to obtain the estimated frequency, estimated pulse width and 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 frequency, 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 application, the first signal and the second signal are down-converted and filtered 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, including:

[0027] The first signal and the second signal are down-converted respectively according to the frequency estimation value 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 input into a digital low-pass filter respectively, and are decimated with K as the order to obtain the first processing signal corresponding to the first signal and the second processing signal corresponding to the second signal.

[0029] In the application, the method further includes:

[0030] The azimuth of arrival estimation value is obtained according to the phase difference estimation value and an interferometer, and the interferometer is used for azimuth of arrival estimation according to the phase difference estimation value.

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

[0032] The signal acquisition module is used for 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.

[0033] The construction signal module is used for signal parameter estimation and signal construction according to a main lobe signal received by a preset platform to obtain a construction signal.

[0034] The signal processing module is used for down-conversion and filtering of 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.

[0035] The construction function module is used for cross-correlation operation of 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.

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

[0037] In the third aspect, the application provides an electronic device, including a memory and a processor.

[0038] The memory stores computer-executable instructions;

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

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

[0041] According to the frequency, the frequency and the pulse width and other parameters measured by the preset platform, the signal is reconstructed, and the frequency conversion and filtering operations are performed, and finally the reconstructed signal is used for sliding cross-correlation accumulation with two channel receiving signals, in a pulse repetition period, the accumulation frame is continuously slid by half the pulse width, and the highest accumulation gain is obtained when the accumulation frame and the pulse are approximately coincident, thereby reducing the gain loss of the noisy pulse train signal, and further 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 DRAWINGS

[0042] Figure 1 The phase difference estimation method flowchart under low signal-to-noise ratio provided for the present embodiment;

[0043] Figure 2 The sliding cross-correlation processing principle diagram provided for the present embodiment;

[0044] Figure 3 The signal phase difference stability diagram under the condition of signal-to-noise ratio-4dB provided for the present embodiment;

[0045] Figure 4 The performance comparison diagram under the signal accumulation time provided for the present embodiment;

[0046] Figure 5 The phase difference estimation device diagram under low signal-to-noise ratio provided for the present embodiment;

[0047] Figure 6 The structure diagram of the electronic device provided by the present application. DETAILED DESCRIPTION

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

[0049] The following detailed description of embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the application as claimed, but merely represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0050] Embodiments

[0051] Figure 1 The flowchart of the phase difference estimation method under low signal-to-noise ratio provided for the present embodiment is shown in FIG. 1, which presents a phase difference estimation method under low signal-to-noise ratio, applied to a phase difference estimation system including a signal receiving model of two array antennas, the method comprising: Figure 1

[0052] S101, obtaining 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.

[0053] wherein the signal received by the reference antenna unit is assumed to be:

[0054]

[0055] wherein A is the amplitude of the signal, f0is the carrier frequency of the signal, T1is the pulse repetition period, and rect((t-nT1) / B) represents a pulse signal with a pulse width of B and a repetition frequency of T1. According to the distance d between the antennas and the signal incidence angle θ, the second antenna unit receives a signal:

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

[0057] The second antenna unit receives a signal s2(t) which can be further expressed as:

[0058] s2(t)=s1(t+Δt);

[0059] wherein Δt=dsin(θ) / c represents the time delay of the signals received by adjacent antennas, 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] The preset platform can refer to other platforms capable of obtaining 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 can refer to a signal received in a main lobe region of an antenna pattern.

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

[0064] The signal construction can refer to reconstruction of a signal based on a result of the signal parameter estimation.

[0065] In some embodiments, the method of obtaining the constructed signal can further include:

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

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

[0068] In some embodiments, since the main lobe signal has a high power, the signal parameter estimation, such as the frequency, the pulse width, and the repetition frequency, is performed using the main lobe signal, so that more accurate signal parameters can be obtained. After the estimated frequency, the estimated pulse width, and the estimated repetition frequency are obtained, an initial constructed signal can be obtained according to the estimated pulse width and the estimated repetition frequency. The initial constructed signal is down-converted and filtered according to the estimated frequency, to obtain the constructed signal.

[0069] Specifically, the constructed signal is obtained according to the estimated frequency, the estimated pulse width, and the estimated repetition frequency, which can include:

[0070] The initial constructed signal is obtained according to the estimated pulse width and the estimated repetition frequency.

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

[0072] The initial constructed signal can be expressed as:

[0073]

[0074] wherein, and are the estimated pulse width and the estimated repetition frequency, respectively.

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

[0076]

[0077] S103, the first signal and the second signal are down-converted and filtered 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 shifting a high frequency signal to baseband (low frequency). By mixing the signal with an estimated frequency of a local oscillator (LO), the frequency spectrum is shifted.

[0079] Filtering operation can refer to retaining valid frequency bands and suppressing out-of-band noise and interference by using filters (such as FIR / IIR).

[0080] In some embodiments, the 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 the first processed signal corresponding to the first signal and the second processed signal corresponding to the second signal can include:

[0081] According to the frequency estimate, the first signal and the second signal are subjected to down-conversion operation respectively to obtain the first down-converted signal and the second down-converted signal;

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

[0083] Specifically, the first signal s1(t) and the second signal s2(t) can be subjected to down-conversion operation according to the frequency estimate

[0084]

[0085]

[0086] S104, according to the first processed signal, the second processed signal and the constructed signal, cross-correlation operation is performed to obtain the first cross-correlation accumulation function of the first processed signal and the constructed signal and the second cross-correlation accumulation function of the second processed signal and the constructed signal.

[0087] Wherein, the cross-correlation operation can refer to a mathematical tool for measuring the similarity of two signals, which is used to analyze the degree of time shift matching of one signal in another signal.

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

[0089] ​​​​​​​​

[0090] wherein, is a first cross-correlation accumulation function, is a second cross-correlation accumulation function, is a first processing signal at a time moment, is a first processing signal at a time moment, is a first processing signal at a time moment, is a constructed signal at a time moment, is a first processing signal at a time moment, is a second processing signal at a time moment, is an estimated value of a time of arrival of a pulse, P is a number of pulses of a pulse train, and N is an accumulation length of each pulse repetition period, N = Bf s / K, f s is a sampling frequency.

[0091] S105, obtaining an estimated value of a phase difference according to the first cross-correlation accumulation function and the second cross-correlation accumulation function.

[0092] Specifically, the estimated value of the time of arrival of the pulse can be initialized as 0, and a plurality of first cross-correlation accumulation function values and a plurality of second cross-correlation accumulation function values can be obtained by sliding at intervals of a half frame length.

[0093] An estimated value of a phase difference can be obtained according to the first cross-correlation accumulation function value with the largest power, the second cross-correlation accumulation function value with the largest power, and an accumulation gain.

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

[0095] Further, a first phase corresponding to the first cross-correlation accumulation function value with the largest power can be obtained according to the first cross-correlation accumulation function value with the largest power and the accumulation gain.

[0096] A second phase corresponding to the second cross-correlation accumulation function value with the largest power can be obtained according to the second cross-correlation accumulation function value with the largest power and the accumulation gain.

[0097] An estimated value of a phase difference can be obtained according to a difference between the first phase and the second phase.

[0098] Specifically, the estimated value of the time of arrival of the pulse can be initialized as 0, and a plurality of first cross-correlation accumulation function values and a plurality of second cross-correlation accumulation function values can be obtained by sliding at intervals of a half frame length. and a corresponding f2are obtained; f 1,max with the largest power and f 2,max are selected, and an accumulation gain is 10log(N) according to a theory of cross-correlation processing; phases are calculated to obtain and and an estimated value of a phase difference is output as .

[0099] ​After the phase difference estimate is obtained, an arrival azimuth estimate can 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] For example, when the method disclosed in this embodiment is used to perform phase measurement, corresponding parameters can be set according to actual conditions. Phase estimation according to the method disclosed in this embodiment includes the following steps:

[0101] Step 1: Build a signal reception model for two array antennas to measure the phase of a pulse train signal. The signal frequency is 4.1 GHz, the sampling frequency is 2 GHz, the pulse repetition period is 10 μs, the pulse width is 1 μs, and the duty cycle is 10%. The signal is incident at a 45° azimuth angle, and the arrival time of the pulse train is unknown, but it is uniformly distributed between [0.5 μs and 9 μs].

[0102] In 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: Based on 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 in this embodiment is as follows: Figure 2 As shown in Figure 1, during sliding coherent integration, 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 at the center of two sliding windows.

[0105] Step 5: Output The performance of the algorithm is evaluated by the phase stability of the two channels, which 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 a signal-to-noise ratio of -4dB 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 duration provided in this embodiment. Figure 4It can be seen that, in the case of a signal accumulation time length of 5 ms, the gain of the embodiment is increased by about 4 dB compared with blind accumulation; meanwhile, with the continuous increase of the accumulation time length, the gain is increased by 0.1 dB under the simulation conditions of 9 ms and 10 ms, which conforms to the theoretical derivation.

[0108] The phase difference estimation method under low signal-to-noise ratio provided by the application reconstructs signals according to parameters such as frequency, repetition frequency and pulse width measured by a preset platform, and performs operations such as frequency down conversion and filtering, and finally uses the reconstructed signals to perform sliding cross-correlation accumulation with two-channel received signals, respectively, in one pulse repetition period, the accumulation frames are continuously slid by half the pulse width length, and the highest accumulation gain is obtained when the accumulation frame and the pulse are approximately coincident, thereby reducing the gain loss of the noisy pulse train signal, and further improving the phase measurement accuracy under low signal-to-noise ratio.

[0109] Figure 5 The low signal-to-noise ratio phase difference estimation device provided by the embodiment is shown in FIG. 1, which comprises: Figure 5

[0110] The signal acquisition module 501 is 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] The signal construction module 502 is configured to perform signal parameter estimation and signal construction on a main lobe signal received by a preset platform to obtain a constructed signal;

[0112] The signal processing module 503 is configured to perform frequency 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] The constructor module 504 is configured to perform cross-correlation operations 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 configured 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 embodiments, the phase difference estimation module 505 is further configured to:

[0116] Initialize the arrival time estimation value of the pulse to 0, and slide at intervals of half frame length to obtain a plurality of first cross-correlation accumulation function values and a plurality of second cross-correlation accumulation function values, respectively;

[0117] ​According to the first cross-correlation accumulation function value with the maximum power, the second cross-correlation accumulation function value with the maximum power and the accumulation gain, a phase difference estimation value is obtained.

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

[0119] According to the first cross-correlation accumulation function value with the maximum power and the accumulation gain, a first phase corresponding to the first cross-correlation accumulation function value with the maximum power is obtained.

[0120] According to the second cross-correlation accumulation function value with the maximum power and the accumulation gain, a second phase corresponding to the second cross-correlation accumulation function value with the maximum power is obtained.

[0121] According to the difference between the first phase and the second phase, a phase difference estimation value is obtained.

[0122] In some embodiments, the signal construction module 502 is further configured to:

[0123] According to the main lobe signal received by the preset platform, signal parameter estimation is performed to obtain an estimated frequency, an estimated pulse width and an estimated repetition frequency.

[0124] According to the estimated frequency, the estimated pulse width and the estimated repetition frequency, a constructed signal is obtained.

[0125] In some embodiments, the signal construction module 502 is further configured to:

[0126] According to the estimated pulse width and the estimated repetition frequency, an initial constructed signal is obtained.

[0127] According to the estimated frequency, the initial constructed signal is subjected to a frequency down-conversion and filtering operation to obtain the constructed signal.

[0128] In some embodiments, the signal processing module 503 is further configured to:

[0129] According to the frequency estimation value, the first signal and the second signal are subjected to a frequency down-conversion operation respectively to obtain a first frequency down-converted signal and a second frequency down-converted signal.

[0130] The first frequency down-converted signal and the second frequency down-converted signal are input into a digital low-pass filter respectively, and are decimated 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 the embodiment can execute the method provided in the method embodiment, and has similar implementation principles and technical effects, which will not be described here.

[0132] Figure 6 The structure schematic diagram of the electronic device provided in the embodiment is shown in FIG. 1. Figure 6As shown, the electronic device 60 provided by the embodiment includes at least one processor 601 and a memory 602. Optionally, the device 60 further includes a communication component 603. The processor 601, the memory 602 and the communication component 603 are connected through a bus 604.

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

[0134] The specific implementation process of the processor 601 can refer to the above-mentioned method embodiment, which has similar implementation principles and technical effects, and will not be described here in detail.

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

[0136] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), for example, at least one disk memory.

[0137] The bus can be an industry standard architecture (ISA) bus, a peripheral component (PCI) bus or an extended industry standard architecture (EISA) bus and the like. The bus can be divided into an address bus, a data bus, a control bus and the like. For the convenience of representation, the bus in the drawings of the application does not limit to only one bus or one type of bus.

[0138] The application further provides a computer program product, including a computer program, which is executed by the processor to realize the above-mentioned method.

[0139] The application further provides a computer readable storage medium, and the computer readable storage medium stores computer execution instructions.

[0140] The readable storage medium can be implemented by any type of volatile or nonvolatile storage devices 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 storage, 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 the 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 an integral part 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 as discrete components in the device.

[0142] The division of units is only a logical function division, and in actual implementation, there can be another division mode, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

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

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

[0145] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0146] Those of ordinary skill in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction-related hardware. 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 a ROM, a RAM, a magnetic disk or an optical disk, and various media that can store program codes.

[0147] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A phase difference estimation method under low signal-to-noise ratio, characterized in that: The method comprises: 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; Signal parameter estimation and signal construction are performed based on 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; 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 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; Obtaining a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function; Obtaining a phase difference estimate value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function, comprising: The arrival time estimation value 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; 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; Obtaining the 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 includes: 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.

2. The phase difference estimation method under low signal-to-noise ratio according to claim 1, 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 t, is the estimated arrival time of the pulse, P is the number of pulses in the pulse train, is the accumulation length of each pulse repetition period, To estimate the repetition frequency.

3. The phase difference estimation method under low signal-to-noise ratio according to claim 1, 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 parameters are estimated based on the main lobe signal received by the preset platform to obtain the estimated frequency, estimated pulse width and estimated repetition rate; A constructed signal is obtained according to the estimated frequency, the estimated pulse width and the estimated repetition rate.

4. The phase difference estimation method under low signal-to-noise ratio according to claim 3, characterized in that: The step of obtaining a constructed signal according to the estimated frequency, the estimated pulse width, and the estimated repetition rate includes: 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.

5. The phase difference estimation method under low signal-to-noise ratio according to claim 1, 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: performing down-conversion operations on the first signal and the second signal respectively according to the frequency estimation value 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 K The order is extracted to obtain a first processed signal corresponding to the first signal and a second processed signal corresponding to the second signal.

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

7. A phase difference estimation device under low signal-to-noise ratio, characterized in that: The device comprises: A signal acquisition module, 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; A signal construction module is used to estimate signal parameters and construct signals based on 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 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, configured to obtain a phase difference estimation value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function; Obtaining a phase difference estimate value according to the first cross-correlation accumulation function and the second cross-correlation accumulation function, comprising: The arrival time estimation value 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; 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; Obtaining the 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 includes: 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.

8. 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 6.

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