Transform Domain Filtering Narrowband Interference Suppression Method and Device

Abstract

The present application discloses a transform domain filtering narrowband interference suppression method and apparatus. The method includes: windowing an input signal to obtain a windowed time domain signal; performing a time-frequency transform on the windowed time domain signal to obtain a frequency domain signal; performing interference suppression on the frequency domain signal, and performing an inverse time-frequency transform on the obtained interference suppression result to obtain an output signal; wherein, the interference suppression includes the following steps: determining whether the absolute value of the frequency domain signal reaches a preset detection threshold; if the absolute value of the frequency domain signal reaches the preset detection threshold, setting the value of the frequency domain signal at this point to a preset value. The technical solution provided by the present application can directly set the points where the absolute value of the frequency domain signal reaches the preset detection threshold to the preset value, realizing a chopping operation on the spectrum in the frequency domain and quickly eliminating narrowband interference.

Description

Technical Field

[0001] This application relates to the technical field of signal processing, and in particular, to a transform domain filtering narrowband interference suppression method and apparatus. Background Art

[0002] The global satellite navigation system plays an increasingly irreplaceable and important role in people's daily lives, and has been increasingly applied in fields such as navigation, timing, and surveying and mapping. The global satellite navigation system mainly includes the Global Positioning System of the United States, the Beidou system of China, the Global Navigation Satellite System of Russia, and the Galileo system of Europe.

[0003] When using the satellite navigation system on vehicles such as cars and ships, the satellite sends navigation signals to the signal receiving device. Due to the very weak satellite navigation signals and the limited demodulation and decoding functions on the receiver, narrowband interference exists in the navigation signals received by the navigation receiver. Summary of the Invention

[0004] Embodiments of the present invention provide a transform domain filtering narrowband interference suppression method and apparatus, which solve the technical problem of narrowband interference existing in navigation signals.

[0005] In a first aspect, embodiments of the present invention provide a transform domain filtering narrowband interference suppression method, the method including: windowing an input signal to obtain a windowed time-domain signal; performing a time-frequency transform on the windowed time-domain signal to obtain a frequency-domain signal; performing interference suppression on the frequency-domain signal, and performing an inverse time-frequency transform on the obtained interference suppression result to obtain an output signal; where the interference suppression includes the following steps: determining whether an absolute value of the frequency-domain signal reaches a preset detection threshold; if the absolute value of the frequency-domain signal reaches the preset detection threshold, setting a value of the frequency-domain signal at this point to a preset value.

[0006] In combination with the first aspect, in a possible implementation manner, before performing the determining whether the absolute value of the frequency-domain signal reaches the preset detection threshold, the preset detection threshold is set through the following steps: calculating an average value of the frequency-domain signal; calculating the preset detection threshold through the following formula: T = K·M; where T represents the preset detection threshold, K represents a threshold coefficient, and M represents the average value of the frequency-domain signal.

[0007] In combination with the first aspect, in a possible implementation manner, the method further includes: setting the preset value to ; where, assuming the frequency-domain signal is X(k) = a k + jb k ; a k and b k are respectively a real part and an imaginary part of the frequency-domain signal, and a phase angle of the windowed time-domain signal is

[0008] Combined with the first aspect, in a possible implementation, the interference suppression is iteratively performed on the frequency-domain signal until a preset iteration termination condition is reached, and the frequency-domain signal after the last iterative processing is used as the interference suppression result.

[0009] Combined with the first aspect, in a possible implementation, the preset iteration termination condition includes: the variance of the frequency-domain signal is less than a preset variance value, or the number of iterations reaches the maximum preset number of iterations.

[0010] Combined with the first aspect, in a possible implementation, the threshold coefficient is set to K = ξD; where D represents the variance of the frequency-domain signal, and ξ represents the conversion coefficient.

[0011] Combined with the first aspect, in a possible implementation, the time-frequency transformation includes a fast Fourier transform, and the inverse time-frequency transformation includes an inverse fast Fourier transform.

[0012] In a second aspect, an embodiment of the present invention provides a transform-domain filtering narrowband interference suppression device. The transform-domain filtering narrowband interference suppression device includes: a windowing module for windowing an input signal to obtain a windowed time-domain signal; a time-frequency transformation module for performing a time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal; an interference suppression module for performing interference suppression on the frequency-domain signal; and an inverse time-frequency transformation module for performing an inverse time-frequency transformation on the obtained interference suppression result to obtain an output signal. Among them, the interference suppression includes the following steps: determining whether the absolute value of the frequency-domain signal reaches a preset detection threshold; if the absolute value of the frequency-domain signal is greater than the preset detection threshold, setting the value of the frequency-domain signal at this point to a preset value.

[0013] Combined with the second aspect, in a possible implementation, before the interference suppression module executes the determination of whether the absolute value of the frequency-domain signal reaches the preset detection threshold, it is used to set the preset detection threshold through the following steps: calculating the mean value of the frequency-domain signal; calculating the preset detection threshold through the following formula: T = K·M; where T represents the preset detection threshold, K represents the threshold coefficient, and M represents the mean value of the frequency-domain signal.

[0014] Combined with the second aspect, in a possible implementation, the interference suppression module is further used to set the preset value to ; where, assuming the frequency-domain signal is X(k) = a k +jb k ; a k and b k are respectively the real part and the imaginary part of the frequency-domain signal, and the phase angle of the windowed time-domain signal is

[0015] In combination with the second aspect, in a possible implementation manner, the interference suppression module is specifically configured to iteratively perform the interference suppression on the frequency-domain signal until a preset iteration termination condition is reached, and use the frequency-domain signal after the last iterative processing as the interference suppression result.

[0016] In combination with the second aspect, in a possible implementation manner, the preset iteration termination condition includes: the variance of the frequency-domain signal is less than a preset variance value, or the number of iterations reaches the maximum preset number of iterations.

[0017] In combination with the second aspect, in a possible implementation manner, the threshold coefficient is set to K = ξ / D; where D represents the variance of the frequency-domain signal, and ξ represents the conversion coefficient.

[0018] In combination with the second aspect, in a possible implementation manner, the time-frequency transformation includes a fast Fourier transform, and the inverse time-frequency transformation includes an inverse fast Fourier transform.

[0019] In a third aspect, an embodiment of the present invention provides a navigation signal receiving device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the transform domain filtering narrowband interference suppression method according to the first aspect and any possible implementation manner of the first aspect.

[0020] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the transform domain filtering narrowband interference suppression method according to the first aspect and any possible implementation manner of the first aspect.

[0021] The technical solution provided in the embodiment of the present invention has at least the following technical effects or advantages:

[0022] The embodiment of the present invention adopts a transform domain filtering narrowband interference suppression method, which includes: obtaining a windowed time-domain signal after windowing an input signal, performing a time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal, then performing interference suppression on the frequency-domain signal and performing an inverse time-frequency transformation on the obtained interference suppression result to obtain an output signal; where the interference suppression includes the following steps: determining whether the absolute value of the frequency-domain signal reaches a preset detection threshold; if the absolute value of the frequency-domain signal reaches the preset detection threshold, then setting the value of the frequency-domain signal at this point to a preset value. This method directly sets the points where the absolute value of the frequency-domain signal reaches the preset detection threshold to the preset value, realizes the chopping operation on the spectrum in the frequency domain, and quickly eliminates narrowband interference. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments of the present invention or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a flowchart of the transform domain filtering narrowband interference suppression method provided by the embodiment of the present invention;

[0025] Figure 2 It is a flowchart of the interference suppression provided by the embodiment of the present invention;

[0026] Figure 3 It is a flowchart of setting a preset detection threshold provided by the embodiment of the present invention;

[0027] Figure 4 It is a schematic structural diagram of the transform domain filtering narrowband interference suppression device provided by the embodiment of the present invention;

[0028] Figure 5 It is a schematic structural diagram of the navigation signal receiving device provided by the embodiment of the present invention;

[0029] Figure 6A It is a waveform diagram of the windowed time domain signal provided by the embodiment of the present invention;

[0030] Figure 6B It is a waveform diagram of the frequency domain signal provided by the embodiment of the present invention;

[0031] Figure 6C It is a waveform diagram of the power spectral density of the frequency domain signal provided by the embodiment of the present invention;

[0032] Figure 7A It is a waveform diagram of the frequency domain signal after interference suppression provided by the embodiment of the present invention:

[0033] Figure 7B It is a waveform diagram of the power spectral density of the frequency domain signal after interference suppression provided by the embodiment of the present invention:

[0034] Figure 7C It is a waveform diagram of the output signal provided by the embodiment of the present invention. Specific embodiments

[0035] When using a satellite navigation system on vehicles such as cars and ships, the satellite sends navigation signals to the signal receiving device. Due to the extremely weak satellite navigation signals and the limited demodulation and decoding functions on the receiver, narrowband interference exists in the navigation signals received by the navigation receiver.

[0036] In view of the above technical problems, the embodiments of the present invention provide a transform domain filtering narrowband interference suppression method and apparatus. Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] The transform domain filtering narrowband interference suppression method provided by the embodiments of the present invention can be applied to navigation signal receiving devices such as satellite receivers, mobile phones, vehicle-mounted navigators, etc. that can receive satellite signals. As Figure 1 shown, the transform domain filtering narrowband interference suppression method provided by the embodiments of the present invention includes steps S101 to S103, taking Figures 6A to 7C as an example.

[0038] Step S101: Window the input signal to obtain a windowed time-domain signal. Figure 6A Shown is an example of the windowed time-domain signal obtained after windowing the input signal.

[0039] Step S102: Perform time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal. Specifically, the time-frequency transformation in step S102 includes the Fast Fourier Transform (abbreviation: FFT). Figure 6B For Figure 6A the windowed time-domain signal in Figure 6B after performing FFT, it can be seen that there are obvious prominent parts in the frequency-domain signal, and these obvious prominent parts are exactly the narrowband interferences existing in the input signal. In addition, Figure 6C also shows Figure 6A the power spectral density of the windowed time-domain signal in

[0040] Step S103: Perform interference suppression on the frequency-domain signal, and perform inverse time-frequency transformation on the obtained interference suppression result to obtain an output signal. Specifically, the inverse time-frequency transformation in step S103 includes the Inverse Fast Fourier Transform (abbreviation: IFFT). After performing interference suppression on Figure 6B the frequency-domain signal in Figure 7A the interference suppression result shown in Figure 7B is obtained. At this time, Figure 7A also shows the power spectral density of the windowed time-domain signal after interference suppression. Then, after performing IFFT on Figure 7C the interference suppression result in

[0041] Among them, the specific execution process of interference suppression in step S103 includes Figure 2 the steps S201 to S203 shown.

[0042] Step S201: Determine whether the absolute value of the frequency-domain signal reaches a preset detection threshold.

[0043] If the absolute value of the frequency-domain signal reaches the preset detection threshold, then execute step S202: Set the value of the frequency-domain signal at this point to a preset value. As Figure 6B shown, there are two prominent parts in the frequency-domain signal. After the chopping operation, that is, setting the value of the frequency-domain signal at this point to the preset value, the two prominent parts are eliminated, thereby quickly eliminating narrowband interference. It should be noted that the absolute value of the frequency-domain signal reaching the preset detection threshold means that the absolute value of the frequency-domain signal is greater than or equal to the preset detection threshold.

[0044] If the absolute value of the frequency-domain signal does not reach the preset detection threshold, then execute step S203: Keep the value of the frequency-domain signal at this point. Continue to refer to Figure 6B shown, except for the two prominent parts of the frequency-domain signal, no chopping operation is performed on other parts, that is, other parts keep the original value of the frequency-domain signal. It should be noted that the absolute value of the frequency-domain signal not reaching the preset detection threshold means that the absolute value of the frequency-domain signal is less than the preset detection threshold.

[0045] The preset detection threshold can be set before executing step S201 through Figure 3 the steps S301 and S302 described.

[0046] Step S301: Calculate the mean value of the frequency-domain signal. Specifically, add the values of each point in the frequency-domain signal, and then divide the obtained sum by the number of points.

[0047] Step S302: Calculate the preset detection threshold through the following formula: T = K·M. Where, T represents the detection threshold, K represents the threshold coefficient, and M represents the mean value of the frequency-domain signal. Specifically, the threshold coefficient K can be determined according to experience. For example, the threshold coefficient K is set to 4.

[0048] The threshold coefficient is set to K = ξ / D; where, D represents the variance of the frequency-domain signal, and ξ represents the conversion coefficient. The above formula gives a specific reference for the threshold coefficient, avoiding blindness in determining the threshold coefficient. Among them, the variance can reflect the degree of deviation between the value of each point in the frequency-domain signal and the mean value. When the conversion coefficient remains unchanged, the larger the variance, the greater the degree of deviation. At this time, the threshold coefficient is smaller, which can reduce the influence of excessive and large deviations on the detection threshold.

[0049] When the absolute value of the frequency-domain signal reaches a preset detection threshold, step S202 is executed, and the preset value in step S202 can be determined in the following manner.

[0050] The method provided by the embodiment of the present invention further includes: setting the preset value to . Wherein, let the frequency-domain signal be X(k) = a k + jb k ; a k and b k are respectively the real part and the imaginary part of the frequency-domain signal, and the phase angle of the windowed time-domain signal is

[0051] Of course, the preset value is not limited to the above determination method, and other methods can also be used to determine it. For example, let the preset value be the mean value of the frequency-domain signal.

[0052] In addition, in the transform-domain filtering narrowband interference suppression method provided by the embodiment of the present invention, the frequency-domain signal is iteratively subjected to interference suppression until the iteration termination condition is reached, and the frequency-domain signal after the last iterative processing is used as the interference suppression result. Iterative interference suppression has a more obvious suppression effect compared with performing interference suppression once, and the error between the final output signal and the true signal is smaller.

[0053] Among them, the iteration termination conditions include: the variance of the frequency-domain signal is less than a preset variance value; or the number of iterations reaches the maximum preset number of iterations. For example, the maximum preset number of iterations is set to 5. When the number of times of iterative interference suppression reaches 5, the iteration is terminated, and the frequency-domain signal after the 5th iterative processing is used as the interference suppression result.

[0054] The following takes 2 iterations of interference suppression as an example to illustrate the transform-domain filtering narrowband interference suppression method provided by the embodiment of the present invention.

[0055] First, window the input signal and perform N-point FFT to obtain the frequency-domain signal; let the frequency-domain signal be X(k) = a k + jb k , a k and b k are respectively the real part and the imaginary part of the frequency-domain signal, and the phase angle of the windowed time-domain signal is

[0056] Secondly, perform the first iteration. Calculate the mean value of the frequency-domain signal X(k) as Among them, N is the number of numerical points in the frequency-domain signal; and set the preset detection threshold to T 1 = K·M 1 , where the threshold coefficient can be set to 4. Then, perform interference decision and suppression on the frequency-domain signal X(k), as shown in the following formula:

[0057]

[0058] Use the signal X after the first iteration of interference suppression 1 (k) to perform a second iteration and calculate the frequency-domain signal X 1 (k), the mean value of which is And set the preset detection threshold to T 2 = K·M 2 , where the threshold coefficient can be set to 4. Then, perform interference decision and suppression on the frequency-domain signal X 1 (k) as shown in the following formula:

[0059]

[0060] Finally, perform time-frequency inverse transformation on the obtained result of the second iteration of interference suppression X 2 (k) to obtain the output signal.

[0061] The transform-domain filtering narrowband interference suppression method provided by the embodiments of the present invention directly sets the points where the absolute value of the frequency-domain signal reaches the preset detection threshold to the preset value, realizing the chopping operation on the spectrum in the frequency domain and quickly eliminating narrowband interference.

[0062] Although the present application provides method operation steps such as in the embodiments or flowcharts, based on routine or non-creative labor, there may be more or fewer operation steps. The step sequence listed in this embodiment is only one way among many step execution sequences and does not represent the only execution sequence. When the actual device or client product executes, it can be executed in the order of the method shown in this embodiment or the drawings or executed in parallel (for example, in an environment of parallel processors or multi-threaded processing).

[0063] As Figure 4 shown, the embodiments of the present invention also provide a transform-domain filtering narrowband interference suppression device 400. The device includes a windowing module 401, a time-frequency transformation module 402, an interference suppression module 403, and a time-frequency inverse transformation module 404. The functions that each module can achieve are described in detail as follows.

[0064] The windowing module 401 is used to window the input signal to obtain a windowed time-domain signal. Figure 6A Shown is an example of the windowed time-domain signal obtained by windowing the input signal by the windowing module 401.

[0065] The time-frequency transformation module 402 is used to perform time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal. Specifically, the time-frequency transformation performed by the time-frequency transformation module 402 includes a fast Fourier transform. Figure 6B For Figure 6AThe frequency-domain signal obtained after performing FFT on the windowed time-domain signal in [[]] by the time-frequency transformation module 402 is from Figure 6B It can be seen that there are obvious prominent parts in the frequency-domain signal, and these obvious prominent parts are exactly the narrowband interferences existing in the input signal. In addition, Figure 6C It also shows in [[]] Figure 6A The power spectral density of the windowed time-domain signal in [[]].

[0066] The interference suppression module 403 is used to suppress the interference of the frequency-domain signal. After the interference suppression module 403 suppresses the interference of the Figure 6B frequency-domain signal in [[]], the interference suppression result shown in Figure 7A is obtained. The Figure 7B in the embodiment of the present invention also shows the power spectral density of the windowed time-domain signal after interference suppression.

[0067] The time-frequency inverse transformation module 404 is used to perform time-frequency inverse transformation on the obtained interference suppression result to obtain the output signal. Specifically, the time-frequency inverse transformation in the time-frequency inverse transformation module 404 includes inverse fast Fourier transform. After the time-frequency inverse transformation module 404 performs IFFT on the Figure 7A interference suppression result in [[]], the output signal shown in Figure 7C can be obtained.

[0068] The interference suppression module 403 is specifically used to perform interference suppression through the following steps.

[0069] Judge whether the absolute value of the frequency-domain signal reaches a preset detection threshold.

[0070] If the absolute value of the frequency-domain signal reaches the preset detection threshold, then set the value of the frequency-domain signal at this point to a preset value. As Figure 6B shown, there are two prominent parts in the frequency-domain signal. After the chopping operation, that is, setting the value of the frequency-domain signal at this point to a preset value, the two prominent parts are eliminated, and thus the narrowband interference is quickly eliminated. It should be noted that the absolute value of the frequency-domain signal reaching the preset detection threshold means that the absolute value of the frequency-domain signal is greater than or equal to the preset detection threshold.

[0071] If the absolute value of the frequency-domain signal does not reach the preset detection threshold, then keep the value of the frequency-domain signal at this point. Continuing to refer to Figure 6B shown, except for the two prominent parts of the frequency-domain signal, no chopping operation is performed on other parts, that is, other parts keep the original value of the frequency-domain signal. It should be noted that the absolute value of the frequency-domain signal not reaching the preset detection threshold means that the absolute value of the frequency-domain signal is less than the preset detection threshold.

[0072] Before the interference suppression module 403 executes the judgment on whether the absolute value of the frequency-domain signal reaches the preset detection threshold, it is specifically used to set the preset detection threshold through the following steps.

[0073] Calculate the mean value of the frequency-domain signal. Specifically, add the values of each point in the frequency-domain signal, and then divide the obtained sum by the number of points.

[0074] Calculate the preset detection threshold through the following formula: T = K·M. Where, T represents the detection threshold, K represents the threshold coefficient, and M represents the mean value of the frequency-domain signal. Specifically, the threshold coefficient K can be determined according to experience. For example, the threshold coefficient K is set to 4.

[0075] The threshold coefficient is set to K = ξ / D; where, D represents the variance of the frequency-domain signal, and ξ represents the conversion coefficient. The above formula gives a specific reference for the threshold coefficient, avoiding blindness in determining the threshold coefficient. Among them, the variance can reflect the degree of deviation between the value of each point in the frequency-domain signal and the mean value. When the conversion coefficient remains unchanged, the larger the variance, the greater the degree of deviation. At this time, the threshold coefficient is smaller, which can reduce the influence of excessive and large deviations on the detection threshold.

[0076] Of course, the determination of the preset detection threshold is not limited by the specific execution process of the interference suppression module 403 described above, and can also be determined by means such as manual setting according to experience in advance.

[0077] The interference suppression module 403 is also used to set the preset value to ; where, let the frequency-domain signal be X(k) = a k +jb k ; a k and b k are the real part and the imaginary part of the frequency-domain signal respectively, and the phase angle of the windowed time-domain signal is

[0078] Of course, the preset value is not limited by the above determination method, and can also be determined by other methods. For example, let the preset value be the mean value of the frequency-domain signal.

[0079] The interference suppression module 403 is specifically used to iteratively perform interference suppression on the frequency-domain signal until the preset iteration termination condition is reached, and use the frequency-domain signal after the last iterative processing as the interference suppression result. Iteratively performing interference suppression has a more obvious suppression effect compared to performing interference suppression once, and the error between the final output signal and the true signal is smaller.

[0080] Among them, the preset iteration termination conditions include: the variance of the frequency-domain signal is less than the preset variance value, or the number of iterations reaches the maximum preset number of iterations. For example, the maximum preset number of iterations is set to 5. When the number of times of iteratively performing interference suppression reaches 5, the iteration is terminated, and the frequency-domain signal after the 5th iterative processing is used as the interference suppression result.

[0081] The following takes the interference suppression with 2 iterations as an example to illustrate the transform domain filtering narrowband interference suppression device provided by the embodiments of the present invention.

[0082] First, the windowing module 401 windows the input signal, and the time-frequency transformation module 402 performs an N-point FFT to obtain a frequency-domain signal; assume the frequency-domain signal is X(k) = a k +jb k , where a k and b k are the real and imaginary parts of the frequency-domain signal respectively, and the phase angle of the windowed time-domain signal is

[0083] Secondly, the interference suppression module 403 performs the first iteration. Calculate the mean value of the frequency-domain signal X(k) as , where N is the number of numerical points in the frequency-domain signal; and set the preset detection threshold as T 1 =K·M 1 , where the threshold coefficient can be set to 4. Then, perform interference decision and suppression on the frequency-domain signal X(k) as shown in the following formula:

[0084]

[0085] The interference suppression module 403 uses the signal X 1 (k) after the first iteration of interference suppression to perform the second iteration, and calculate the mean value of the frequency-domain signal X 1 (k) as ; and set the preset detection threshold as T 2 =K·M 2 , where the threshold coefficient can be set to 4. Then, perform interference decision and suppression on the frequency-domain signal X 1 (k) as shown in the following formula:

[0086]

[0087] Finally, the interference suppression module 403 performs an inverse time-frequency transformation on the obtained result X 2 (k) of the second iteration of interference suppression to obtain the output signal.

[0088] The transform domain filtering narrowband interference suppression device 400 provided by the embodiments of the present invention can directly set the points where the absolute value of the frequency-domain signal reaches the preset detection threshold to the preset value, realizing the chopping operation on the spectrum in the frequency domain and quickly eliminating the narrowband interference.

[0089] The devices or modules illustrated in the above embodiments may be specifically implemented by computer chips or entities, or by products with certain functions. For the convenience of description, when describing the above devices, they are divided into various modules according to functions and described separately. When implementing the present application, the functions of each module may be implemented in one or more software and / or hardware. Of course, the module implementing a certain function may also be implemented by combining multiple sub-modules or sub-units.

[0090] Some modules in the device of the present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media including storage devices.

[0091] As Figure 5 shown, an embodiment of the present invention provides a navigation signal receiving device 500, which includes a memory 502 and a processor 501 connected by a bus, and a computer program stored in the memory 502 and executable on the processor; when the processor 501 executes the computer program, it implements the transform domain filtering narrowband interference suppression method provided by the embodiment of the present invention.

[0092] An embodiment of the present invention also provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, it implements the transform domain filtering narrowband interference suppression method provided by the embodiment of the present invention.

[0093] The above storage medium includes but is not limited to random access memory (English: Random Access Memory; abbreviation: RAM), read-only memory (English: Read-Only Memory; abbreviation: ROM), cache (English: Cache), hard disk (English: Hard Disk Drive; abbreviation: HDD) or memory card (English: Memory Card). The memory may be used to store computer program instructions.

[0094] The methods, devices or modules in this application can be implemented in the form of computer-readable program code. The controller can be implemented in any appropriate manner. For example, the controller can take the form of a microprocessor or a processor, a computer-readable medium storing computer-readable program code (such as software or firmware) executable by the (micro)processor, logic gates, switches, application specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that, in addition to implementing the controller in the form of pure computer-readable program code, the same function can be achieved by logically programming the method steps to make the controller in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be regarded as a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as either software modules for implementing the method or the structures within the hardware component.

[0095] From the description of the above embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary hardware. Based on such an understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product or can also be reflected in the implementation process of data migration. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disks, optical discs, etc., and includes several instructions for causing a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the methods of various embodiments or some parts of the embodiments of this application.

[0096] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. All or part of this application can be used in many general-purpose or special-purpose computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on.

[0097] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A transform domain filtering narrowband interference suppression method, characterized in that, it includes: Window the input signal to obtain a windowed time-domain signal; Perform time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal; Suppress interference on the frequency-domain signal, and perform inverse time-frequency transformation on the obtained interference suppression result to obtain an output signal; wherein, the interference suppression includes the following steps: Judge whether the absolute value of the frequency-domain signal reaches a preset detection threshold; If the absolute value of the frequency-domain signal reaches the preset detection threshold, set the value of the frequency-domain signal at this point to a preset value; Before performing the judgment on whether the absolute value of the frequency-domain signal reaches the preset detection threshold, set the preset detection threshold through the following steps: Calculate the mean value of the frequency-domain signal; Calculate the preset detection threshold through the following formula: T = K·M; where, T represents the preset detection threshold, K represents the threshold coefficient, and M represents the mean value of the frequency-domain signal; Further comprising: setting the preset value to wherein, let the frequency-domain signal be X(k) = a k + jb k ; a k and b k are respectively the real part and the imaginary part of the frequency-domain signal, and the phase angle of the windowed time-domain signal is 2. The transform domain filtering narrowband interference suppression method according to claim 1, characterized in that, Iteratively perform the interference suppression on the frequency-domain signal until a preset iteration termination condition is reached, and use the frequency-domain signal after the last iterative processing as the interference suppression result.

3. The method according to claim 2, characterized in that, The preset iteration termination condition includes: the variance of the frequency-domain signal is less than a preset variance value, or the number of iterations reaches the maximum preset number of iterations.

4. The transform domain filtering narrowband interference suppression method according to claim 1, characterized in that, The threshold coefficient is set to K = ξ / D; where, D represents the variance of the frequency-domain signal, and ξ represents the conversion coefficient.

5. The transform domain filtering narrowband interference suppression method according to claim 1, characterized in that, The time-frequency transformation includes fast Fourier transform, and the inverse time-frequency transformation includes inverse fast Fourier transform.

6. A transform domain filtering narrowband interference suppression device, characterized in that, it includes: A windowing module for windowing the input signal to obtain a windowed time-domain signal; A time-frequency transformation module for performing time-frequency transformation on the windowed time-domain signal to obtain a frequency-domain signal; An interference suppression module for suppressing interference on the frequency-domain signal; An inverse time-frequency transformation module for performing inverse time-frequency transformation on the obtained interference suppression result to obtain an output signal; wherein, the interference suppression includes the following steps: Judge whether the absolute value of the frequency-domain signal is greater than or equal to a preset detection threshold; If the absolute value of the frequency-domain signal is greater than the preset detection threshold, set the value of the frequency-domain signal at this point to a preset value; Before performing the judgment on whether the absolute value of the frequency-domain signal reaches the preset detection threshold, set the preset detection threshold through the following steps: Calculate the mean value of the frequency-domain signal; Calculate the preset detection threshold through the following formula: T = K·M; where, T represents the preset detection threshold, K represents the threshold coefficient, and M represents the mean value of the frequency-domain signal; Further comprising: setting the preset value to wherein, let the frequency-domain signal be X(k) = a k + jb k ; a k and b k are respectively the real part and the imaginary part of the frequency-domain signal, and the phase angle of the windowed time-domain signal is 7. A navigation signal receiving device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the transform domain filtering narrowband interference suppression method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the transform domain filtering narrowband interference suppression method according to any one of claims 1 to 5.

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