An adaptive and accurate sensing and suppression method for radar jamming pulses

Abstract

The present invention belongs to the technical field of communication equipment, and specifically relates to an adaptive accurate perception and suppression method of radar interference pulses. In modern communications, there is strong radar pulse interference in areas with harsh electromagnetic environments, which affects the normal reception and demodulation of voice signals, brings serious listening pressure to station personnel, and seriously affects business efficiency. The present invention adopts modern digital processing technology to completely solve the defects of the original analog suppression circuit, has a high degree of automation, a wide range of applications, and precise suppression adjustment, so that it can more effectively eliminate the interference of radar pulses on voice signals and achieve the effect of reducing the work fatigue of staff. The present invention includes the following main steps: intermediate frequency signal acquisition, signal conversion cache, radar pulse early warning, pulse parameter measurement, pulse waveform matching, suppression parameter calculation, demodulation suppression output, pulse sample update, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of communication equipment, and in particular relates to a method for adaptively and accurately sensing and suppressing radar interference pulses. Background Art

[0002] When modern communication receiving equipment is used to receive voice signals, there are sudden co-frequency electromagnetic interferences at many receiving frequencies. One of the typical scenarios is the interference of high-intensity radar pulses. This pulse is mixed in the voice signal demodulation output of the receiving equipment, seriously affecting the normal reception and monitoring of voice signals, and sometimes even interrupting the listening service. At the same time, the salesperson is very likely to suffer from auditory fatigue and increase work pressure in a long-term harsh listening environment. Therefore, it is necessary to accurately sense the radar pulses and suppress them accurately before demodulation output to adapt to the deteriorating electromagnetic environment, reduce work fatigue, and improve the efficiency of the listening service.

[0003] Existing modern communication receiving equipment generally does not have radar pulse suppression technology. The few devices that have suppression technology generally use dedicated analog circuits in the RF front end to achieve it. The disadvantage of this technology is that the suppression circuit is fixed and cannot be adjusted. The important characteristic parameters such as the width and pulse intensity of the suppressed radar pulse are fixed, resulting in the following defects:

[0004] 1) The application scope is small and it cannot effectively identify and suppress radar interference pulses of various types;

[0005] 2) The suppression accuracy is poor, the suppression degree cannot be adjusted, and there are residual pulses that cannot be suppressed;

[0006] 3) There is error suppression, resulting in loss of valid voice information.

[0007] In view of the above defects, it is necessary to adopt modern digital processing technology to replace analog processing technology to solve the above defects. Summary of the invention

[0008] The purpose of the present invention is to provide an adaptive and precise sensing and suppression method for radar interference pulses, that is, to adopt modern digital processing technology to solve a number of technical defects such as small applicability range and poor suppression accuracy due to the fixed analog suppression circuit, which can automatically and quickly discover and accurately adjust the suppression parameters of various radar pulse types, and can adapt to the trend of the deteriorating electromagnetic environment, so as to more accurately suppress radar pulses and realize the need to more effectively reduce the work fatigue of staff while further improving business efficiency.

[0009] In order to solve the above technical problems, the present invention provides an adaptive and accurate sensing and suppression method for radar interference pulses, comprising the following steps:

[0010] Step 1: The acquisition module samples the intermediate frequency signal from the RF front end through a high-speed ADC;

[0011] Step 2: Perform orthogonal transformation and primary filtering extraction on the collected digital intermediate frequency signal;

[0012] Step 3: Amplitude and frequency detection, extract instantaneous amplitude and frequency information, and store them in the onboard DDR3 cache queue in real time;

[0013] Step 4: The monitoring module monitors the cache queue, and if a radar pulse signal is detected, it proceeds to step 5; if no radar pulse signal is detected, it proceeds to step 3;

[0014] Step 5: The measurement module accurately measures the characteristic parameters of the current suspected radar pulse;

[0015] Step 6: The recognition module performs sample matching recognition on the pulse parameters. If the match is successful, it will proceed to step 7. If the match fails, it will proceed to step 11.

[0016] Step 7: Mark the radar pulse type and use it as an index to retrieve the sample library to obtain the suppression parameters in the specified format;

[0017] Step 8: Use the demodulation output sampling rate as an index to look up the table to obtain the fixed delay sample length of the demodulation output, and calculate the starting point and sample length of the precise radar pulse sample before the demodulation output;

[0018] Step 9: Obtain the suppression coefficient of each pulse suppression sample point through the proportional relationship between the pulse amplitude peak value and the mean value and the current demodulated signal amplitude mean value, and obtain the pulse sample point comprehensive suppression parameter in combination with step 8;

[0019] Step 10: suppress the corresponding sample points of the voice demodulation signal according to the pulse sample point comprehensive suppression parameter and then output it, and then go to step 3;

[0020] Step 11: Identify whether the suspected radar pulse meets the radar pulse characteristics. If not, proceed to step 1.

[0021] Furthermore, the measured data includes one or more pulse parameters of pulse width, pulse amplitude peak value, pulse amplitude mean value, pulse interval period, and pulse frequency.

[0022] Furthermore, the method further comprises the following steps:

[0023] Step 12: If the suspected radar pulse meets the radar pulse characteristics, the current radar pulse waveform parameters are added as a new type and entered into the sample library in the specified format, and then go to step 8.

[0024] The beneficial effects of the present invention are:

[0025] 1. Use digital signal processing methods to solve the defects of analog suppression circuits. Since the radar interference pulses are accurately sensed by the digital processor and the comprehensive suppression parameters of the radar interference pulses are obtained, the voice demodulation signal containing the radar interference pulses can be accurately suppressed, which completely solves the multiple defects of the analog suppression circuit. Through the comparison and verification of multiple actual signals of business units, the digital suppression technology of the present invention has a substantially improved suppression effect than analog suppression, and the beneficial effect is significant;

[0026] 2. The main performance index requirements for radar pulse suppression of various standards are as follows: a. When the pulse width is 0.5 ms to 10 ms and the pulse peak value / signal average value RATIO is ≥ 20dB, the pulse peak value / signal average value RATIO is ≤ 2dB (typical value); b. When the voice demodulation output is used, the deviation between the start and end sample points of radar pulse suppression is ≤ 2 points; c. Automatically adapt to various radar pulses, accurately identify, and there is no false suppression.

[0027] 3. It completely solves many defects of analog suppression circuits, adaptively and accurately senses radar pulses, and accurately suppresses them before voice demodulation output; it has the ability to adapt to the deteriorating electromagnetic environment and automatically handle new unknown radar types; the present invention greatly reduces work fatigue of staff and effectively improves the business efficiency of equipment.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the main hardware components of the present invention;

[0031] Figure 2 It is a flow chart of the demodulation process of the conventional voice signal of the device signal of the present invention;

[0032] Figure 3 is an overall processing flow chart of the present invention;

[0033] Figure 4 It is a comparative verification diagram of the original analog suppression of the present invention and the digital suppression of the present invention on the same actual received signal;

[0034] Figure 5This is a comparison diagram before and after inhibition of the present invention;

[0035] Figure 6 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example:

[0038] like Figures 1 to 6 As shown, an adaptive accurate sensing and suppression method for radar jamming pulses adopts digital signal processing technology to accurately sense and suppress the output of radar jamming pulses mixed with voice demodulation signals. The main hardware is not limited to a radio frequency front-end module, an ADC analog-to-digital converter, a digital signal processing platform, an onboard DDR3 memory, an onboard FLASH memory, a DAC digital-to-analog converter, and an audio filter amplifier circuit.

[0039] Among them, the digital signal processing platform adopts a universal signal processing carrier board based on the ZYNQ digital processor. The ZYNQ digital processor adopts FPGA+ARM architecture and is divided into PL side (FPGA) and PS side (ARM). The content of the present invention is mainly implemented by the PL side.

[0040] The universal signal processing carrier board has built-in FLASH storage devices and high-speed DDR3 cache chips, which are read and written by the ZYNQ processor. The FLASH memory is used to store known radar pulse sample data when the power is off. It is read in when the device is powered on and initialized. Once a new radar pulse type is sensed to be connected during operation, it is written in real time as a new sample. The high-speed DDR3 cache chip is designed as a cache queue to store the data stream when the pulse sample is matched.

[0041] The RF front end mainly realizes the frequency conversion of the RF signal input by the antenna, and realizes the output of the intermediate frequency signal after filtering, amplification and other related circuit processing, thereby providing the intermediate frequency signal for the digital acquisition ADC.

[0042] The digital voice demodulation signal is converted from digital to analog by the DAC device, and the differential analog signal output by it is filtered and amplified by the differential operational amplifier and then drives the headphones / speakers for monitoring.

[0043] like Figure 2The figure shows a conventional voice signal demodulation processing flow chart of the device signal, wherein the digital signal processing platform uses a general signal processing carrier board based on the ZYNQ digital processor to construct a general software radio hardware processing platform. The PL end (FPGA) of the ZYNQ digital processor receives one (or more) intermediate frequency signals collected by the ADC for digital down-conversion and then demodulates and outputs the signals. The digital down-conversion is to sample the digital intermediate frequency signal of the ADC, generate two orthogonal baseband signals I and Q through digital mixing, and enter the multi-stage filtering extraction cascade to reduce the data flow for narrowband digital filtering processing, generate two orthogonal I and Q narrowband baseband signals of low data flow, and demodulate I and Q to obtain the voice signal output.

[0044] The multi-stage filter decimation cascade uses the primary "CIC decimation filter" and the post-stage "polyphase FIR decimation filter cascade" to downsample the data stream to match the output sampling rate of the narrowband voice signal. The decimation factor of the entire data stream is 1600, of which the CIC decimation filter decimation factor is 25, the data output sampling rate is 2.048MHz, the polyphase FIR decimation filter cascade decimation factor is 64--128, and the data output sampling rate is 32KHz--16KHz, that is, the final voice signal output sampling rate is reduced to 32KHz--16KHz.

[0045] like Figure 3 As shown, the overall processing flow chart of the present invention is as follows Figure 3 As shown, the following steps are included:

[0046] Step 1: The acquisition module samples the intermediate frequency signal from the RF front end through a high-speed ADC with a sampling rate of 51.2MHz;

[0047] Step 2: Perform orthogonal transformation and primary CIC filtering extraction on the collected digital intermediate frequency signal. The I and Q data stream rate of this stage of baseband orthogonal signals is 2.048MHz.

[0048] Step 3: Amplitude and frequency detection: perform amplitude and frequency detection on the I and Q signals, extract the instantaneous amplitude information and frequency information, and store the instantaneous amplitude information as time domain waveform samples in real time into the onboard DDR3 cache queue. The data stream rate write rate is 2.048MHz. The onboard DDR3 cache capacity of a single channel is set to 80M bytes, which can continuously store 10 milliseconds of time domain waveform samples, which can contain at least two consecutive radar pulse cycles.

[0049] Step 4: The monitoring module monitors the cache queue. Once the amplitude value of the time domain waveform sample point exceeds the set threshold, the suspected radar pulse signal is marked as out of the connection and the process goes to step 5. Otherwise, the process goes to step 1.

[0050] Step 5: The measurement module accurately measures the characteristic parameters of the current suspected radar pulse, including pulse width, pulse amplitude peak value, pulse amplitude mean value, pulse frequency and other pulse parameters, and then proceeds to step 6;

[0051] Step 6: The recognition module continuously uses correlation operations to perform sample matching and recognition on the continuous pulse waveforms and sample waveforms before and after the cache queue. Each waveform sample stores a complete sample point of the normalized amplitude of a single pulse time domain waveform of a known radar type. According to the correlation results of pulse width, pulse amplitude and pulse interval period, once the match is successful, it will proceed to step 7, otherwise it will proceed to step 11; the storage format of the waveform sample is shown in Table 1, and it is read into the internal memory of the processor by the onboard FLASH memory when the device is powered on and initialized;

[0052] Table 1. Sample library of known radar pulse type waveforms

[0053]

[0054] Step 7: Mark the radar pulse type and the starting subscript and sample length of the radar pulse sample point;

[0055] Step 8: Use the radar pulse type and demodulation output sampling rate as the index to look up the table to obtain the fixed delay sample length of the demodulation output, and calculate the starting subscript and sample length of the precise radar pulse sample of the demodulation output; the storage format of the table is shown in Table 2, and is read into the internal memory of the processor by the onboard FLASH memory when the device is powered on and initialized;

[0056] Table 2. Table of known radar pulse type suppression parameters

[0057]

[0058] Step 9: Calculate the suppression coefficient of the current pulse suppression sample point through the proportional relationship between the pulse amplitude peak value and the mean value and the current demodulated signal amplitude mean value, and calculate the pulse sample point comprehensive suppression parameters in combination with step 8, including: the subscript and suppression value of the pulse sample point in the demodulated output data stream that the voice demodulation signal needs to suppress;

[0059] Step 10: Suppress the corresponding samples of the speech demodulation signal according to the pulse sample comprehensive suppression parameters and then output them, and then go to step 1.

[0060] Step 11: Determine whether the suspected radar pulse meets the radar pulse characteristics. The judgment criteria are pulse parameters such as pulse width, pulse amplitude peak value, pulse amplitude mean, pulse frequency, and pulse interval period. If it meets the requirements, proceed to step 12. If it does not meet the requirements, proceed to step 1.

[0061] Step 12: Add the current radar pulse waveform parameters as a new type to Table 1, and write Table 1 into the onboard FLASH memory. At the same time, write the radar pulse waveform sample library into the onboard FLASH memory according to the specified format of Table 2, and go to step 8. Add the radar pulse waveform parameters as a new type to Table 1.

[0062] like Figure 4 As shown, the upper signal in the figure adopts the digital suppression of the present invention, and the suppression effect is obvious and accurate, while the lower signal adopts the original analog suppression, and there are obviously residual pulses that cannot be completely suppressed.

[0063] like Figure 5 As shown in the figure, it is the continuous signal actually received by the business unit. The first half of the figure is the demodulated output waveform with the radar pulse suppression function turned off, and there is obviously strong radar pulse interference. The second half is the demodulated output waveform with the radar pulse suppression function turned on. It can be seen that the strong radar pulse interference is accurately suppressed, meeting the requirements of the main performance indicators.

[0064] In summary: digital signal processing methods are used to solve the defects of analog suppression circuits, and radar interference pulses are accurately sensed through digital processors to obtain comprehensive suppression parameters of radar interference pulses, and voice demodulation signals containing radar interference pulses are accurately suppressed. When testing radars of various standards, the pulse width is 0.5 milliseconds to 10 milliseconds, and the pulse peak value / signal mean value RATIO is ≥ 20dB. The pulse peak value / signal mean value RATIO ≤ 2dB (typical value), and the pulse suppression start and end sample point deviation is ≤ 2 points during voice demodulation output, and the radar pulse is accurately identified without erroneous suppression. The present invention thoroughly solves many defects of analog suppression circuits and effectively improves the business efficiency of equipment.

[0065] The various devices selected in this application are all universal standard parts or parts known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0066] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0068] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An adaptive and accurate sensing and suppression method for radar jamming pulses, characterized in that: The steps include: Step 1: The acquisition module samples the intermediate frequency signal from the RF front end through a high-speed ADC; Step 2: Perform orthogonal transformation and primary filtering extraction on the collected digital intermediate frequency signal; Step 3: Amplitude and frequency detection, extract instantaneous amplitude and frequency information, and store them in the onboard DDR3 cache queue in real time; Step 4: The monitoring module monitors the cache queue, and proceeds to step 5 if a radar pulse signal is detected, and proceeds to step 3 if no radar pulse signal is detected; Step 5: The measurement module accurately measures the characteristic parameters of the current suspected radar pulse; Step 6: The recognition module performs sample matching recognition on the pulse parameters. If the match is successful, it will proceed to step 7. If the match fails, it will proceed to step 11. Step 7: Mark the radar pulse type and use it as an index to retrieve the sample library to obtain the suppression parameters in the specified format; Step 8: Use radar pulse type and demodulation output sampling rate as index to look up the table to obtain the fixed delay sample length of the demodulation output, and calculate the starting subscript and sample length of the precise radar pulse sample of the demodulation output Step 9: Calculate the suppression coefficient of the current pulse suppression sample point by the proportional relationship between the pulse amplitude peak value and mean value and the current demodulated signal amplitude peak value and mean value, and obtain the pulse sample point comprehensive suppression parameter by combining step 8; Step 10: suppress the corresponding sample points of the voice demodulation signal according to the pulse sample point comprehensive suppression parameter and then output it, and then go to step 1; Step 11: Determine whether the suspected radar pulse meets the radar pulse characteristics. If it meets the characteristics, proceed to step 12; if it does not meet the characteristics, proceed to step 1; Step 12: Enter the current radar pulse waveform parameters as a new type into the sample library in the specified format and go to step 8.

2. The method for adaptively accurately sensing and suppressing radar jamming pulses according to claim 1, characterized in that: In step 5, the measured data includes one or more pulse parameters of pulse width, pulse amplitude peak value, pulse amplitude mean value, pulse interval period, and pulse frequency.

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