A new GNSS fast sweeping frequency jamming suppression method

Abstract

The application relates to a new GNSS fast sweep frequency interference suppression method. The method comprises the following steps: acquiring a sampling data sequence of a satellite navigation receiving device, adopting a pre-set low-pass filter to perform low-pass filtering on the sampling data sequence to obtain output data; adopting a conjugate operation mode to acquire an envelope value of the output data to obtain pulse envelope data; according to a characteristic value in the pulse envelope data, an interference detection threshold is calculated; according to the interference detection threshold and a pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data to obtain interference suppression data. The method has low operation complexity.

Description

Technical Field

[0001] This application relates to the field of satellite navigation technology, and in particular to a novel method for suppressing GNSS fast frequency sweep interference. Background Technology

[0002] Electromagnetic interference detection and elimination has always been a hot and crucial issue in the application of Global Navigation Satellite Systems (GNSS). From the perspective of its source, electromagnetic interference can be divided into unintentional interference and malicious interference. The most frequently mentioned type of malicious interference is a device called PPDs (Personal Privacy Devices), a small and inexpensive jammer that can suppress GNSS signals across the entire frequency band by emitting rapid frequency sweep jamming signals. In numerous GNSS interference incidents both domestically and internationally, it has been found that many were caused by truck drivers installing and activating PPD jamming devices on their vehicle's cigarette lighter sockets to evade company monitoring.

[0003] Interference emitted by devices such as PPDs sweeps frequencies very quickly, covering tens of megabits of bandwidth within tens of microseconds, exhibiting characteristics of non-stationary interference. Conventional interference suppression methods model interference as a stationary random process, which proves ineffective against non-stationary interference like fast-sweeping interference. Time-frequency analysis-based anti-interference methods project interference into a two-dimensional time-frequency space and utilize the sparsity of fast-sweeping interference in this space for detection and suppression. This method has been shown to have good suppression effects on fast-sweeping interference, but its implementation is complex. Summary of the Invention

[0004] Therefore, it is necessary to provide a new method for suppressing GNSS fast frequency sweep interference to address the aforementioned technical problems.

[0005] A novel GNSS fast frequency sweep interference suppression method, the method comprising:

[0006] The sampling data sequence of the satellite navigation receiving device is obtained, and the sampling data sequence is low-pass filtered using a pre-set low-pass filter to obtain the output data.

[0007] The envelope value of the output data is obtained by using a conjugate operation method to obtain pulse envelope data;

[0008] The interference detection threshold is calculated based on the feature values ​​in the pulse envelope data;

[0009] Based on the interference detection threshold and the pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data to obtain interference suppression data.

[0010] In one embodiment, the method further includes: applying a pre-set low-pass filter to the sampled data sequence to obtain output data as follows:

[0011]

[0012] Where y(n) is the output data of the low-pass filter, h(k), k=1,2,…,L is the tap coefficient of the digital low-pass filter, L is the length of the digital low-pass filter, x(n) represents the sampled data sequence, and N represents the length of the sampled data sequence.

[0013] In one embodiment, the method further includes: obtaining the envelope value of the output data using a conjugate operation to obtain pulse envelope data as follows:

[0014] z(n) = [y(n) * conj(y(n))] 1 / 2 n = 1, 2, ..., N

[0015] Where z(n) represents the pulse envelope data, and conj(·) represents the conjugate operation.

[0016] In one embodiment, the method further includes: calculating an interference detection threshold based on feature values ​​in the pulse envelope data, including:

[0017] Based on the feature values ​​in the pulse envelope data, the interference detection threshold is calculated as follows:

[0018] z th =z min +0.05(z max -z min )

[0019] In one embodiment, the method further includes: constructing a decision algorithm based on the interference detection threshold and the pulse detection zeroing scheme as follows:

[0020]

[0021] A novel GNSS fast frequency sweep interference suppression device, the device comprising:

[0022] The low-pass filter module is used to acquire the sampled data sequence of the satellite navigation receiver and perform low-pass filtering on the sampled data sequence using a pre-set low-pass filter to obtain output data.

[0023] An envelope calculation module is used to obtain the envelope value of the output data using a conjugate operation method to obtain pulse envelope data.

[0024] The threshold construction module is used to calculate the interference detection threshold based on the feature values ​​in the pulse envelope data;

[0025] The suppression module is used to suppress interference in the pulse envelope data according to the interference detection threshold and the pulse detection zeroing scheme, so as to obtain interference suppression data.

[0026] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0027] The sampling data sequence of the satellite navigation receiving device is obtained, and the sampling data sequence is low-pass filtered using a pre-set low-pass filter to obtain the output data.

[0028] The envelope value of the output data is obtained by using a conjugate operation method to obtain pulse envelope data;

[0029] The interference detection threshold is calculated based on the feature values ​​in the pulse envelope data;

[0030] Based on the interference detection threshold and the pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data to obtain interference suppression data.

[0031] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0032] The sampling data sequence of the satellite navigation receiving device is obtained, and the sampling data sequence is low-pass filtered using a pre-set low-pass filter to obtain the output data.

[0033] The envelope value of the output data is obtained by using a conjugate operation method to obtain pulse envelope data;

[0034] The interference detection threshold is calculated based on the feature values ​​in the pulse envelope data;

[0035] Based on the interference detection threshold and the pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data to obtain interference suppression data.

[0036] The aforementioned novel GNSS fast frequency sweep interference suppression method, apparatus, computer equipment, and storage medium acquire a sampled data sequence from a satellite navigation receiver. A pre-set low-pass filter is used to low-pass filter the sampled data sequence to obtain output data. A conjugate operation is used to obtain the envelope value of the output data, yielding pulse envelope data. An interference detection threshold is calculated based on the characteristic values ​​in the pulse envelope data. Interference is suppressed on the pulse envelope data according to the interference detection threshold and a pulse detection nulling scheme, resulting in suppressed interference data. By suppressing fast frequency sweep interference through low-pass filtering and pulse detection nulling, the high implementation complexity or poor suppression effect of existing technologies are overcome, and this method can be used to provide frequency sweep interference protection capabilities for satellite navigation receivers. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating a novel GNSS fast frequency sweep interference suppression method in one embodiment;

[0038] Figure 2 This is a temporal envelope diagram of the data before low-pass filtering in one embodiment;

[0039] Figure 3 This is a time-domain envelope diagram of the data after low-pass filtering in one embodiment;

[0040] Figure 4 This is a two-dimensional time-frequency distribution diagram of data before fast frequency sweep interference suppression in one embodiment;

[0041] Figure 5 This is a two-dimensional time-frequency distribution diagram of data after fast frequency sweep interference suppression in one embodiment;

[0042] Figure 6 This is a structural block diagram of a novel GNSS fast frequency sweep interference suppression device in one embodiment;

[0043] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0045] In one embodiment, such as Figure 1 As shown, a novel GNSS fast frequency sweep interference suppression method is provided, including the following steps:

[0046] Step 102: Obtain the sampling data sequence of the satellite navigation receiving device, and perform low-pass filtering on the sampling data sequence using a pre-set low-pass filter to obtain the output data.

[0047] In this step, the sampling data sequence of the satellite navigation receiver is x(1), x(2), ..., x(N), where N is the data length. A digital low-pass filter can be used to implement the low-pass filter. Specifically, if the RF front-end bandwidth of the satellite navigation receiver is B... f The sampling rate of AD sampling is f s Therefore, the passband cutoff frequency of the digital low-pass filter is 0.4B. f The stopband cutoff frequency is 0.4 GHz. f +0.1f s The passband amplitude fluctuation is 1dB, and the stopband attenuation is 40dB. Based on these four parameters, the filter tap coefficients and filter length can be designed. Digital low-pass filter design is common knowledge in the field of digital signal processing, and will not be elaborated here.

[0048] Step 104: Obtain the envelope value of the output data using the conjugate operation method to obtain the pulse envelope data.

[0049] Step 106: Calculate the interference detection threshold based on the feature values ​​in the pulse envelope data.

[0050] Step 108: Based on the interference detection threshold and the pulse detection zeroing scheme, the pulse envelope data is subjected to interference suppression to obtain interference suppression data.

[0051] The novel GNSS fast frequency sweep interference suppression method described above acquires the sampled data sequence from the satellite navigation receiver, applies a pre-set low-pass filter to the sampled data sequence to obtain output data, and uses a conjugate operation to obtain the envelope value of the output data, thus obtaining pulse envelope data. Based on the characteristic values ​​in the pulse envelope data, an interference detection threshold is calculated. According to the interference detection threshold and a pulse detection nulling scheme, interference is suppressed on the pulse envelope data to obtain suppressed interference data. By suppressing fast frequency sweep interference through low-pass filtering and pulse detection nulling, this method overcomes the problems of high implementation complexity or poor suppression effect in existing technologies and can be used to provide frequency sweep interference protection capabilities for satellite navigation receivers.

[0052] In one embodiment, a pre-set low-pass filter is used to perform low-pass filtering on the sampled data sequence to obtain the output data as follows:

[0053]

[0054] Where y(n) is the output data of the low-pass filter, h(k), k=1,2,…,L is the tap coefficient of the digital low-pass filter, L is the length of the digital low-pass filter, x(n) represents the sampled data sequence, and N represents the length of the sampled data sequence.

[0055] Furthermore, the envelope value of the output data is obtained by using a conjugate operation, resulting in the pulse envelope data as follows:

[0056] z(n) = [y(n) * conj(y(n))] 1 / 2 n = 1, 2, ..., N

[0057] Where z(n) represents the pulse envelope data, and conj(·) represents the conjugate operation.

[0058] In one embodiment, the maximum and minimum values ​​of the data network z(n) are first determined by comparison.

[0059] They are defined as follows:

[0060] z max =max[z(n)], n = 1, 2, ..., N

[0061] z min =min[z(n)], n=1,2,...,N

[0062] The function max(·) represents the maximum value, and the function min(·) represents the minimum value.

[0063] Then, the interference detection threshold is calculated using the following formula:

[0064] z th =z min +0.05(z max -z min )

[0065] Furthermore, during interference detection, for each low-pass filter output data y(n), the data envelopment value is checked to see if it exceeds the interference detection threshold. If it exceeds the threshold, the data is set to zero; otherwise, it remains unchanged. This process can be described by the following formula:

[0066]

[0067] In the formula, That is, the data after interference suppression according to the method of the present invention is output to the backend capture and tracking module for further processing.

[0068] As can be seen from the above steps, the most computationally intensive part of the fast frequency sweep interference suppression process is the general low-pass filtering process. The computational complexity of the entire process is very small, about an order of magnitude lower than that of traditional methods.

[0069] Specifically, Figure 2 and Figure 3 This is the time-domain envelope diagram of the data before and after low-pass filtering obtained by the method of this invention. In this embodiment, the RF front-end bandwidth of the navigation receiver is 20MHz, the AD sampling adopts an orthogonal sampling method, the sampling rate is 20.48MHz, and the sampled data includes satellite navigation signals, receiver thermal noise, and fast frequency sweep interference. The fast frequency sweep interference is a periodic linear frequency sweep interference with a sweep bandwidth of 20MHz in one period, a sweep rate of 0.4MHz / us, and an interference power 60dB greater than the satellite signal power. (Comparison) Figure 2 and Figure 3 As can be seen, before low-pass filtering, due to the continuous temporal presence of fast frequency sweep interference, the data envelope remains within a relatively large value range. After low-pass filtering, the data envelope exhibits a pulsed pattern. Furthermore, Figure 4 and Figure 5 This is a two-dimensional time-frequency distribution diagram of the data before and after fast sweep frequency interference suppression obtained by the method of the present invention. It can be seen that after processing with the method of the present invention, fast sweep frequency interference is effectively eliminated.

[0070] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0071] In one embodiment, such as Figure 6 As shown, a novel GNSS fast frequency sweep interference suppression device is provided, comprising: a low-pass filter module 202, an envelope calculation module 204, a threshold construction module 206, and a suppression module 208, wherein:

[0072] Low-pass filtering module 202 is used to acquire the sampling data sequence of the satellite navigation receiving device, and to perform low-pass filtering on the sampling data sequence using a pre-set low-pass filter to obtain output data;

[0073] Envelope calculation module 204 is used to obtain the envelope value of the output data by using a conjugate operation method to obtain pulse envelope data;

[0074] The threshold construction module 206 is used to calculate the interference detection threshold based on the feature values ​​in the pulse envelope data;

[0075] The suppression module 208 is used to suppress interference in the pulse envelope data according to the interference detection threshold and the pulse detection zeroing scheme to obtain interference suppression data.

[0076] In one embodiment, the low-pass filtering module 202 is further configured to perform low-pass filtering on the sampled data sequence using a pre-set low-pass filter, to obtain the output data as follows:

[0077]

[0078] Where y(n) is the output data of the low-pass filter, h(k), k=1,2,…,L is the tap coefficient of the digital low-pass filter, L is the length of the digital low-pass filter, x(n) represents the sampled data sequence, and N represents the length of the sampled data sequence.

[0079] In one embodiment, the envelope calculation module 204 is further configured to obtain the envelope value of the output data using a conjugate operation method, resulting in pulse envelope data as follows:

[0080] z(n) = [y(n) * conj(y(n))] 1 / 2 n = 1, 2, ..., N

[0081] Where z(n) represents the pulse envelope data, and conj(·) represents the conjugate operation.

[0082] In one embodiment, the feature values ​​are the maximum and minimum values; the threshold construction module 206 is further configured to calculate the interference detection threshold based on the feature values ​​in the pulse envelope data:

[0083] z th =z min +0.05(z max -z min )

[0084] In one embodiment, the suppression module 208 is further configured to construct a decision algorithm based on the interference detection threshold and the pulse detection zeroing scheme:

[0085]

[0086] Specific limitations regarding the new GNSS fast frequency sweep interference suppression device can be found in the limitations of the new GNSS fast frequency sweep interference suppression method described above, and will not be repeated here. Each module in the aforementioned new GNSS fast frequency sweep interference suppression device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0087] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a novel GNSS fast sweep frequency interference suppression method. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0088] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0089] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method described above.

[0090] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0091] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0092] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A novel GNSS fast frequency sweep interference suppression method, characterized in that, The method includes: The sampling data sequence of the satellite navigation receiving device is obtained, and the sampling data sequence is low-pass filtered using a pre-set low-pass filter to obtain the output data. The envelope value of the output data is obtained by using a conjugate operation method to obtain pulse envelope data; The interference detection threshold is calculated based on the feature values ​​in the pulse envelope data; Based on the interference detection threshold and the pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data to obtain interference suppression data; The step of obtaining the pulse envelope data by using a conjugate operation method includes: The envelope value of the output data is obtained by using a conjugate operation, resulting in the pulse envelope data as follows: in, Represents pulse envelope data. This indicates the conjugate operation. The output data is the low-pass filtered data, and N represents the length of the sampled data sequence.

2. The method according to claim 1, characterized in that, The step of applying a pre-set low-pass filter to the sampled data sequence to obtain output data includes: The sampled data sequence is low-pass filtered using a pre-set low-pass filter to obtain the following output data: in, , k =1,2,…, L , where is the tap coefficient of the digital low-pass filter. L The length of the digital low-pass filter. This represents the sequence of sampled data.

3. The method according to claim 1, characterized in that, The characteristic values ​​are the maximum and minimum values; Based on the feature values ​​in the pulse envelope data, the interference detection threshold is calculated, including: Based on the feature values ​​in the pulse envelope data, the interference detection threshold is calculated as follows: in, This represents the maximum value of the pulse envelope data. This represents the minimum value of the pulse envelope data. This indicates the interference detection threshold.

4. The method according to claim 3, characterized in that, Based on the interference detection threshold and the pulse detection zeroing scheme, interference suppression is performed on the pulse envelope data, including: Based on the interference detection threshold and the pulse detection zeroing scheme, the decision algorithm is constructed as follows: This represents the data after line interference suppression.

5. A novel GNSS fast frequency sweep interference suppression device, characterized in that, The device includes: The low-pass filter module is used to acquire the sampled data sequence of the satellite navigation receiver and perform low-pass filtering on the sampled data sequence using a pre-set low-pass filter to obtain output data. An envelope calculation module is used to obtain the envelope value of the output data using a conjugate operation method to obtain pulse envelope data. The threshold construction module is used to calculate the interference detection threshold based on the feature values ​​in the pulse envelope data; The suppression module is used to suppress interference in the pulse envelope data according to the interference detection threshold and the pulse detection zeroing scheme to obtain interference suppressed data. The envelope calculation module is also used to obtain the envelope value of the output data using a conjugate operation method, resulting in pulse envelope data as follows: in, Represents pulse envelope data. This indicates the conjugate operation. The output data is the low-pass filtered data, and N represents the length of the sampled data sequence.

6. The apparatus according to claim 5, characterized in that, The low-pass filtering module is also used to perform low-pass filtering on the sampled data sequence using a pre-set low-pass filter, to obtain the output data as follows: in, , k =1,2,…, L , where is the tap coefficient of the digital low-pass filter. L The length of the digital low-pass filter. This represents the sequence of sampled data.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

Images