Anti-interference method based on double-frequency-point communication mode

Abstract

The invention relates to a communication interference technology, in particular to an anti-interference method based on a double-frequency-point communication mode, which is used for solving the problems of difficulty in interference source judgment, lack of interference source characteristic judgment and positioning and insufficient anti-interference means in a traditional communication system. According to the method, through comprehensive judgment in three aspects of monitoring of related indexes of double-frequency-point communication receiving signal power, frequency stability and bit error rate, whether the receiving signal power fluctuation is caused by equipment faults or external interference is effectively distinguished, the problem source can be more accurately positioned, and by constructing a receiving point at a specific position, the problem can be accurately positioned. The method comprises the following steps: estimating the position of an interference source by using signal receiving time and intensity, adjusting the frequency of a normal signal to a proper position for a periodic interference signal according to the fundamental frequency and integral multiple frequency characteristics of the periodic interference signal, and iteratively updating a filter coefficient according to the error between an input signal and an expected signal by presetting a filter parameter for a non-periodic interference signal. And the filter continuously adapts to an interference environment, so that an input signal is close to an expected signal.

Description

Technical Field

[0001] The present invention relates to a communication interference technology, and in particular to an anti-interference method based on a dual-frequency communication mode. Background Art

[0002] Interference refers to some unstable radio waves that hinder signal reception during radio reception;

[0003] When the received signal power of traditional communication systems fluctuates abnormally, it is difficult to distinguish whether it is caused by a device failure or external interference. As a result, in actual applications, communication equipment frequently experiences unstable transmission, affecting communication quality and efficiency.

[0004] In terms of interference source analysis, the existing technology cannot accurately determine the characteristics of the interference signal in most cases. When determining the location of the interference source, there is a lack of effective positioning methods, making it difficult for the communication system to take targeted measures to avoid interference. This not only causes the performance of the communication system to degrade in an interference environment, but may also cause a waste of resources, such as unnecessary power increase or frequency band switching, and cannot truly solve the interference problem.

[0005] In view of the above technical problems, this application proposes a solution. Summary of the invention

[0006] The purpose of the present invention is to make a comprehensive judgment by monitoring the three aspects of the received signal power, frequency stability and bit error rate related indicators of dual-frequency communication, effectively distinguish whether the received signal power fluctuation is caused by equipment failure or external interference, and locate the root cause of the problem more accurately. By constructing a receiving point at a specific location, the signal reception time and strength are used to estimate the location of the interference source. For periodic interference signals, the normal signal frequency is adjusted to a suitable position according to its baseband and integer multiple frequency characteristics. For non-periodic interference signals, the filter parameters are preset and the filter coefficients are iteratively updated according to the error between the input signal and the expected signal, so that the filter continuously adapts to the interference environment and makes the input signal close to the expected signal. The problems of difficulty in judging the interference source, lack of interference source characteristic judgment and positioning, and insufficient anti-interference means in traditional communication systems are solved, and an anti-interference method based on dual-frequency communication is proposed.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The anti-interference method based on the dual-frequency communication mode includes:

[0009] Interference detection and analysis: Continuously monitor the power of the received signal of dual-frequency communication, and determine whether fluctuations occur by calculating the slope; calculate the frequency stability and bit error rate related indicators, quantify the processing results to obtain the failure rate, and eliminate the interference of equipment failure factors; calculate the signal power of the transmitting end and compare it with the actual power to determine whether there is interference in the transmission and determine the location of the interference source;

[0010] Periodicity judgment of interference signal: Use signal monitoring equipment to record the receiving time to form a time series, calculate the autocorrelation function, and preliminarily judge the interference signal period based on the peak value of the function at the non-zero time delay; compare the signal length with the preliminarily judged period, and extend the signal length to three interference signal periods when the signal length is insufficient, check the peak value of the autocorrelation function at integer multiples of the period, and determine whether the interference signal is periodic and the period value in combination with spectrum analysis;

[0011] Anti-interference strategy: If the interference signal is periodic, adjust the normal signal frequency and detect the interference ratio. If it is still interfered with, change the dual-frequency transmission frequency. If the interference signal is non-periodic, suppress the interference by iteratively updating the filter coefficients. At the same time, set several receiving points to detect the signal strength and merge them. The number of receiving points is set to twice the number of receiving points where the interference signal appears.

[0012] As a preferred embodiment of the present invention, the steps of determining whether the communication signal fluctuates are as follows:

[0013] Step 1: Monitor the received signal power of dual-frequency communication, record the monitoring time and the received signal power, draw coordinate points in the coordinate system with the monitoring time and the received signal power as the x-axis and y-axis, connect adjacent coordinate points, and calculate the slope value XL of each connecting line segment i , i is the number of connecting line segments;

[0014] Step 2: If the preset slope threshold XL max <|XL i |, determine that the received signal power has a value exceeding the preset fluctuation range, mark the slope corresponding to the value exceeding the preset fluctuation range as an abnormal slope, and analyze the cause of the abnormal slope.

[0015] As a preferred embodiment of the present invention, the cause of the abnormal slope is determined by the following steps:

[0016] Step 1: randomly select a set of abnormal slopes, take the frequency data of any two time points in the time period corresponding to the abnormal slope, calculate the difference between the frequency data of the two time points, and divide the absolute value of the calculated difference by the nominal frequency to obtain the frequency stability data of the two time points in the corresponding time period. If the specified frequency stability index is less than the frequency stability data, it is determined that the communication equipment may have a fault;

[0017] Step 2: Obtain the theoretical bit error rate, denoted as BER LL , if β2 * BER LL < BER SJ < β1 * BER LL , BER SJ is the actual bit error rate, and both β1 and β2 are preset bit error rate comparison ratios. Then, it is determined that the communication device may have a fault, and BER SJ and β1 * BER LL and β2 * BER LL are calculated for their differences; if the calculated difference is positive, the calculated difference data is taken, denoted as WMC. If the calculated difference is negative, the absolute value data of the calculated difference is taken, denoted as WMC;

[0018] Step 3: Comprehensively evaluate the result data calculated in Step 1 and Step 2 to obtain the failure rate of the communication device ρ1 and ρ2 are weight coefficients, and σ f and σ B are the frequency stability data at two time points within the corresponding time period respectively; if the preset fault threshold GZ max < GZ, it is determined that the communication device has a fault; otherwise, it is determined that the fluctuation of the received signal power is not caused by a communication device fault.

[0019] As a preferred embodiment of the present invention, calculate the signal power at the transmitting end and compare it with the actual value to determine whether there is interference during transmission. The specific analysis steps are as follows:

[0020] Step 1: Obtain the transmitted power data of the interference signal and the normal signal power data without interference at the receiving end, and calculate the interference ratio of the interference signal to the normal signal. The interference ratio of the interference signal to the normal signal is equal to the transmitted power of the interference signal divided by the normal signal power without interference at the receiving end. If the preset signal interference rate threshold is less than the interference ratio of the interference signal to the normal signal, it is determined that the interference signal causes interference to the normal signal, and the position of the interference source is determined; otherwise, it is determined that the interference signal does not cause interference to the normal signal;

[0021] Step 2: With the communication signal receiving end as the center, construct three receiving points at a set distance from the communication signal receiving end with an included angle of 120°, denoted as receiving point A, receiving point B, and receiving point C. Record the time and intensity of the signals received at the three receiving points, and determine that the receiving point that receives the signal earliest and has the strongest signal reception intensity is the closest to the interference source. The propagation speed of the signal is V GR , then the distances between the estimated interference source and the three receiving points are respectively D Agr = V GR * t A , D Bgr = VGR *t B and D Cgr =V GR *t C , t A ,t B and t C The time when the signal is received at the three receiving points A, B, and C respectively. The three receiving points are the centers of the circles, and the radii are D Agr , D Bgr and D Cgr Draw circles, and mark the point where the three circles intersect as the location of the interference source.

[0022] As a preferred implementation of the present invention, the steps for determining the periodicity of the interference signal are as follows:

[0023] Step 1: Connect a signal monitoring device with a timestamp function to the receiving end of the communication system, record the receiving time while receiving the signal through the signal monitoring device, sort the received signal according to the receiving time to form a time series, assume that the interference signal data sequence is x(n), and calculate the correlation of the data sequence with a signal length of N at time n and time n+m through the autocorrelation function; if the autocorrelation function has a peak at a non-zero time delay m, it is determined that the interference period of the interference signal is m;

[0024] Step 2: Compare the signal length N with the period m. If N>3m, it is determined that the signal length allows for periodicity determination; otherwise, the signal length N is extended to three interference periods; the values ​​of the autocorrelation function at 2m and 3m are determined. If the autocorrelation function also has peaks at 2m and 3m, it is determined that the interference period of the interference signal is m; otherwise, it is determined that the interference signal does not have periodicity;

[0025] Step 3: Perform Fourier transform on the interference signal through a spectrum analyzer to obtain a spectrum that displays the signal in a graphical manner. Mark the discrete spectral lines of the spectrum in the graphical spectrum, record the minimum value in each group of marks as the fundamental frequency f0, and then compare the other marks with the fundamental frequency. If the spectrum data of other marks are all integer multiples of the fundamental frequency data, then the spectrum marked as the fundamental frequency is determined to be the fundamental frequency, and the period of the interference signal is determined.

[0026] Step 4: If the autocorrelation function also has peaks at 2m and 3m, and the spectrum data of other markers are integer multiples of the baseband data, it is determined that the interference signal has periodicity.

[0027] As a preferred embodiment of the present invention, the anti-interference strategy of the periodic interference signal is as follows:

[0028] Step 1: If the interference signal is periodic and the fundamental frequency of the interference signal is f0, adjust the frequency of the normal signal to the intermediate value of the frequencies of the two interference signals. After the adjustment is completed, detect the interference ratio IR1 of the interference signal to the normal signal. If the preset signal interference rate threshold IR max > IR1, it means that the interference signal does not interfere with the normal signal; if the preset signal interference rate threshold IR max < IR1, it is determined that the interference signal still interferes with the normal signal, and the interference of the interference signal is avoided;

[0029] Step 2: Randomly set g1 signal receiving points identical to the communication signal receiving point near the communication signal receiving point. Set the frequencies of the set signal receiving points within the frequency band permitted by the communication system and at frequency points with an interval from the interference signal frequency. Then, use a spectrum scanner to detect the signal strength of the signal receiving points. Arrange the later-set g1 signal receiving points in ascending order of signal strength, and select the last g2 signal receiving points for signal strength merging. The selected quantity g2 is twice the number of interference signal receiving points, and the quantity of g1 is greater than twice that of g2;

[0030] Step 3: Receive the signals of two frequency points simultaneously and perform joint processing on them using the maximum ratio combining technique. According to the strength and quality of the signals of the two frequency points, different weights are assigned for combining; the signal strength of the preset frequency point 1 is XH1, the signal strength of frequency point 1 is XH2, and the signal strength data XH after maximum ratio combining is XH = a1 * XH1 + a2 * XH2, where a1 and a2 are weight coefficients; if the signals of both frequency points are interfered, select the signals of four or more frequency points, and then perform pairwise combination, and select the two with the strongest combined signal strength and assign them to the corresponding two frequency points; if only the signal of one frequency point is interfered, then perform pairwise combination on the signals of two or more frequency points.

[0031] As a preferred embodiment of the present invention, the anti-interference strategy for non-periodic interference signals is as follows:

[0032] Step 1: Preset the filter coefficients and the input signal of the filter. Then, calculate the value of the output signal according to the input signal through the adaptive filtering formula, and calculate the difference between the input signal and the desired signal, and record the difference as the error E(r), where r is the sample number;

[0033] Step 2: Set the step size factor as μ and initialize the filter coefficients as C(0). For each input signal sample A(r), according to the current filter coefficients C(r) and the formula for calculating the output signal, the output signal can be calculated. Then, calculate the error between the input signal and the desired signal. According to the error and the input signal, according to the formula C i(r+1)=C i (r)+2μ*E(r)*A(ri), update the filter coefficient to C(r+1);

[0034] Step 3: Repeat the operations of steps 1 and 2, and continuously process new input signal samples so that the filter coefficients continuously adapt to the interference environment; the preset error value is ε, and when the error E(r) between the input signal and the expected signal = ε, stop the iterative operation.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. Comprehensively judge by monitoring the power of the received signal, frequency stability and bit error rate related indicators of dual-frequency communication, effectively distinguish whether the fluctuation of the received signal power is caused by equipment failure or external interference. In the case that traditional technology is difficult to accurately judge, the root cause of the problem can be more accurately located, avoiding wrong solutions due to misjudgment, and improving the operation and maintenance efficiency of the communication system;

[0037] 2. By constructing receiving points at specific locations and using signal reception time and strength to estimate the location of interference sources, compared with the lack of effective interference source positioning methods in existing technologies, this can provide an important basis for subsequent targeted anti-interference measures and help improve the anti-interference effect;

[0038] 3. For periodic interference signals, the normal signal frequency can be adjusted to a suitable position according to its base frequency and integer multiple frequency characteristics. If it is still interfered after adjustment, the dual-frequency transmission frequency can be further changed. This strategy of flexibly adjusting the frequency according to the interference situation can better avoid the interference frequency and improve the communication stability and reliability compared with the traditional fixed frequency communication method; for non-periodic interference signals, by pre-setting the filter parameters, the filter coefficients are iteratively updated according to the error between the input signal and the expected signal, so that the filter can continuously adapt to the interference environment, and finally make the input signal close to the expected signal; combined with the setting of multiple receiving points and the merging of signal strength, the signal quality is effectively improved, the bit error rate is reduced, the reliability and continuity of communication are ensured, and the shortcomings of the existing technology in ensuring communication quality when dealing with non-periodic interference are made. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0040] Figure 1 It is a system method diagram of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of 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.

[0042] Example:

[0043] See also Figure 1 As shown, the anti-interference method based on the dual-frequency communication mode includes:

[0044] Monitor the received signal power of dual-frequency communication, record the monitoring time and the received signal power, draw coordinate points in a coordinate system with the monitoring time and the received signal power as the x-axis and y-axis, connect adjacent coordinate points, and calculate the slope value XL of each connecting line segment i , i is the number of connecting line segments; if the preset slope threshold XL max <|XL i |, determining that the received signal power has a value exceeding a preset fluctuation range, and analyzing the cause of the value exceeding the preset fluctuation range;

[0045] Obtain the time period when the slope changes, obtain the working parameter data of the communication device during the slope change period through the built-in monitoring module of the communication device, and take the frequency data of any two time points during the time period when the slope changes, that is, the frequencies at t1 and t2 are f(t1) and f(t2) respectively, then the frequency stability during the time period from t1 to t2 is f0 is the nominal frequency. If the specified frequency stability index σ B <σ f , then it is determined that the communication equipment may be faulty, σ f and σ B are the frequency stability data at two time points in the corresponding time period; in the additive white Gaussian noise channel, theoretically, there is a certain functional relationship between the bit error rate BER and the signal-to-noise ratio SNR. The theoretical bit error rate in unit time t If the actual bit error rate BER SJ <β1*BER LL And BER SJ >β2*BER LL , β1 and β2 are both preset bit error rate comparison ratios; calculate the difference between the actual bit error rate and the theoretical bit error rate, that is, obtain it by subtracting the actual bit error rate from the theoretical bit error rate. If the comparison result is BER SJ >β2*BER LL , the calculated difference is used as WMC. If the comparison result is BER SJ<β1*BER LL If the calculated difference is taken as the absolute value as the WMC, it indicates that the difference between the actually measured bit error rate and the theoretically calculated bit error rate based on the measured signal-to-noise ratio is large, and it is determined that the communication device may have a fault. Quantify the processing results of the two judgments to obtain the failure rate of the communication device ρ1 and ρ2 are weighting coefficients; if the preset fault threshold GZ max <GZ, it is determined that the communication device has a fault; otherwise, it is determined that the fluctuation of the received signal power is not caused by a communication device fault;

[0046] Record the signal reception power JSP received by the receiving end of the communication device TX The gains of the transmitting and receiving antennas are G T and G R respectively, and the free space path loss of the communication signal from the transmitting end to the receiving end d1 is the distance between the transmitting end and the receiving end, and γ is the wavelength of the communication signal; then the communication signal power FSP transmitted by the transmitting end is calculated TXJ = JSP TX + L FS -(G T + G R ), Compare the calculated communication signal power FSP TXJ of the transmitting end with the communication signal power FSP TX of the transmitting end. If the preset power comparison threshold α > FSP TXJ - FSP TX , it is determined that there is an interference signal during the transmission of the communication signal.

[0047] Interference analysis: The transmission power of the interference signal G = G T + G R , d2 is the distance between the interference source and the receiving point; the normal signal power without interference at the receiving end Then the interference ratio of the interference signal to the normal signal If the preset signal interference rate threshold IR max < IR, it is determined that the interference signal has interfered with the normal signal, and the position of the interference source is determined; otherwise, it is determined that the interference signal has not interfered with the normal signal;

[0048] With the receiving end of the communication signal as the center, three receiving points are constructed at a set distance from the receiving end of the communication signal with an included angle of 120°. Denote them as receiving point A, receiving point B, and receiving point C. Record the time and intensity of the signals received by the three receiving points, and determine that the receiving point that receives the signal earliest and has the strongest signal reception intensity is the closest to the interference source. The propagation speed of the signal is V GR, then the estimated distances between the interference source and the three receiving points are D Agr =V GR *t A , D Bgr =V GR *t B and D Cgr =V GR *t C , t A ,t B and t C The time when the signal is received at the three receiving points A, B, and C respectively. The three receiving points are the centers of the circles, and the radii are D Agr , D Bgr and D Cgr Draw circles, and mark the point where the three circles intersect as the location of the interference source;

[0049] Connect a signal monitoring device with a timestamp function to the receiving end of the communication system. The signal monitoring device records the receiving time while receiving the signal. The received signals are sorted according to the receiving time to form a time series. Let the interference signal data sequence be x(n), and the autocorrelation function N is the length of the data sequence, m is the time delay, x(n) and x(n+m) are the values ​​of the signal at time n and time n+m respectively; the autocorrelation function has a peak at a non-zero time delay m, that is, the signal has a high similarity at the time when m samples are separated, and the interference period of the interference signal is determined to be m;

[0050] Verify periodicity: compare the signal length N with the period m. If N>3m, the signal length is sufficient and will not affect the judgment of the period. Otherwise, the signal length N is extended. The values ​​of the autocorrelation function at 2m and 3m are judged. If the autocorrelation function also has peaks at 2m and 3m, the interference period of the interference signal is judged to be m. Otherwise, the interference signal is judged to have no periodicity. The interference signal is Fourier transformed by a spectrum analyzer to obtain a spectrum that displays the signal in a graphical manner, with the vertical axis representing the signal amplitude and the horizontal axis representing the frequency. The discrete spectral lines of the spectrum in the graphical spectrum are marked, and the minimum value among the many marks is recorded as the fundamental frequency f0. The other marks are then compared with the fundamental frequency. If the spectrum data of the other marks are integer multiples of the fundamental frequency data, the spectrum marked as the fundamental frequency is determined to be the fundamental frequency, and the period of the interference signal is determined. If the autocorrelation function also has peaks at 2m and 3m, and the spectrum data of other markers are integer multiples of the baseband data, it is determined that the interference signal has periodicity, and the period T=m.

[0051] Anti-interference strategy: If the interference signal is periodic and the fundamental frequency of the interference signal is f0, then the positions of integer multiples of the fundamental frequency will also interfere with the normal signal. Adjust the frequency of the normal signal to the middle value of the two interference signal frequencies. After the adjustment, detect the interference ratio IR1 of the interference signal to the normal signal. If IR max < IR1, it is determined that the interference signal still interferes with the normal signal, and the interference of the interference signal is avoided; if IR max > IR1, it means that the interference signal does not interfere with the normal signal;

[0052] Randomly set several signal receiving points identical to the communication signal receiving point near the communication signal receiving point. Set the frequencies of the set signal receiving points within the frequency band permitted by the communication system and at frequency points with a certain interval from the interference signal frequency. Then, use a spectrum scanner to detect the signal strength of the signal receiving points. Arrange the several later-set signal receiving points in ascending order of signal strength, select the signal receiving points with stronger signal strength, and perform signal strength merging; receive the signals of two frequency points simultaneously, and use the maximum ratio combining technique to jointly process them. According to the strength and quality of the signals of the two frequency points, different weights are assigned for merging; assume the signal strength of frequency point one is XH1, the noise power is ZS1, the signal strength of frequency point two is XH2, and the noise power is ZS2. The signal strength data XH after maximum ratio combining is XH = a1 * XH1 + a2 * XH2, Through maximum ratio combining, the signals of the two frequency points are integrated, and a combined signal strength better than that of a single frequency point signal is obtained; if the signals of both frequency points are interfered, select the signals of four or more frequency points, and then perform pairwise merging. Select the two with the strongest combined signal strength and assign them to the corresponding two frequency points; if only the signal of one frequency point is interfered, then for the signals of two or more frequency points, and then perform pairwise merging;

[0053] If the interference signal is not periodic, assume the input signal of the filter is A(r), the desired signal is B(r), and the filter coefficient is preset as C(r). Calculate the output signal r is the sample number, and L is the filter order. Then the error E(r) between the input signal and the desired signal is E(r) = B(r) - D(r); set the step factor as μ and initialize the filter coefficient as C(0). For each input signal sample A(r), according to the current filter coefficient C(r) and the formula for calculating the output signal, the output signal can be calculated. Then calculate the error between the input signal and the desired signal. According to the error and the input signal, according to the formula C i (r + 1) = C i(r)+2μ*E(r)*A(ri) updates the filter coefficient to C(r+1), repeats the above filter coefficient update operation, continuously processes new input signal samples, so that the filter coefficient continuously adapts to the interference environment. When the error E(r) between the input signal and the expected signal approaches zero, the closer the input signal is to the expected signal, the preset error value is ε. When the error E(r) between the input signal and the expected signal = ε, stop the iterative operation.

[0054] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. The anti-interference method based on the dual-frequency communication mode is characterized in that: include: Interference detection and analysis: Continuously monitor the received signal power of dual-frequency communication and determine whether fluctuations occur by calculating the slope; Calculate the frequency stability and bit error rate related indicators, quantify the processing results to obtain the failure rate, and eliminate the interference of equipment failure factors; Calculate the signal power at the transmitting end and compare it with the actual power to determine whether there is interference in the transmission and determine the location of the interference source; Periodicity judgment of interference signal: Use signal monitoring equipment to record the receiving time to form a time series, calculate the autocorrelation function, and preliminarily judge the interference signal period based on the peak value of the function at the non-zero time delay; compare the signal length with the preliminarily judged period, and extend the signal length to three interference signal periods when the signal length is insufficient, check the peak value of the autocorrelation function at integer multiples of the period, and determine whether the interference signal is periodic and the period value in combination with spectrum analysis; Anti-interference strategy: If the interference signal is periodic, adjust the normal signal frequency and detect the interference ratio. If it is still interfered with, change the dual-frequency transmission frequency. If the interference signal is non-periodic, suppress the interference by iteratively updating the filter coefficients. At the same time, set several receiving points to detect the signal strength and merge them. The number of receiving points is set to twice the number of receiving points where the interference signal appears.

2. The anti-interference method based on the dual-frequency communication mode according to claim 1, characterized in that: The steps to determine whether the communication signal fluctuates are as follows: Step 1: Monitor the received signal power of dual-frequency communication, record the monitoring time and the received signal power, draw coordinate points in the coordinate system with the monitoring time and the received signal power as the x-axis and y-axis, connect adjacent coordinate points, and calculate the slope value XL of each connecting line segment i , i is the number of connecting line segments; Step 2: If the preset slope threshold XL max <|XL i |, determine that the received signal power has a value exceeding the preset fluctuation range, mark the slope corresponding to the value exceeding the preset fluctuation range as an abnormal slope, and analyze the cause of the abnormal slope.

3. The anti-interference method based on the dual-frequency communication mode according to claim 2 is characterized in that: To determine the cause of the abnormal slope, the steps are as follows: Step 1: randomly select a set of abnormal slopes, take the frequency data of any two time points in the time period corresponding to the abnormal slope, calculate the difference between the frequency data of the two time points, and divide the absolute value of the calculated difference by the nominal frequency to obtain the frequency stability data of the two time points in the corresponding time period. If the specified frequency stability index is less than the frequency stability data, it is determined that the communication equipment may have a fault; Step 2: Get the theoretical bit error rate, denoted as BER LL , if β2*BER LL <BER SJ <β1*BER LL , BERS J is the actual bit error rate, β1 and β2 are both preset bit error rate comparison ratios, then it is determined that the communication equipment may have a fault and the BER is calculated SJ and β1*BER LL and β2*BER LL The difference between If the calculated difference is positive, take the calculated difference data and record it as WMC. If the calculated difference is negative, take the absolute value data of the calculated difference and record it as WMC. Step 3: Comprehensively evaluate the result data calculated in steps 1 and 2 to obtain the communication equipment failure rate ρ1 and ρ2 are weight coefficients, σ f and σ B They are the frequency stability data at two time points in the corresponding time period; If the preset fault threshold GZ max <GZ, it is determined that the communication device has a fault; otherwise, it is determined that the fluctuation of the received signal power is not caused by the communication device fault.

4. The anti-interference method based on the dual-frequency communication mode according to claim 1, characterized in that: Calculate the signal power at the transmitting end and compare it with the actual power to determine whether there is interference in the transmission. The specific analysis steps are as follows: Step 1: Obtain the transmission power data of the interference signal and the power data of the normal signal that is not interfered with at the receiving end, and calculate the interference ratio of the interference signal to the normal signal. The interference ratio of the interference signal to the normal signal is equal to the transmission power of the interference signal divided by the normal signal power that is not interfered with at the receiving end. If the preset signal interference rate threshold is less than the interference ratio of the interference signal to the normal signal, it is determined that the interference signal has caused interference to the normal signal, and the location of the interference source is determined; otherwise, it is determined that the interference signal has not caused interference to the normal signal; Step 2: With the communication signal receiving end as the center, three receiving points are constructed at a set distance from the communication signal receiving end with an angle of 120°, which are recorded as receiving point A, receiving point B and receiving point C. The time and strength of the signals received by the three receiving points are recorded, and it is determined that the receiving point that receives the signal earliest and has the strongest signal reception strength is closest to the interference source. The signal propagation speed is V GR , then the estimated distances between the interference source and the three receiving points are D Agr =V GR *t A , D Bgr =V GR *t B and D Cgr =V GR *t C , t A ,t B and t C The time when the signal is received at the three receiving points A, B, and C respectively. The three receiving points are the centers of the circles, and the radii are D Agr , D Bgr and D Cgr Draw circles, and mark the point where the three circles intersect as the location of the interference source.

5. The anti-interference method based on the dual-frequency communication mode according to claim 1, characterized in that: The steps for determining the periodicity of interference signals are as follows: Step 1: Connect a signal monitoring device with a timestamp function to the receiving end of the communication system, record the receiving time while receiving the signal through the signal monitoring device, sort the received signals according to the receiving time to form a time series, and assume that the interference signal data sequence is x(n). Calculate the correlation of the data sequence with a signal length of N at time n and time n+m through the autocorrelation function; If the autocorrelation function has a peak at a non-zero time delay m, the interference period of the interference signal is determined to be m; Step 2: Compare the signal length N with the period m. If N>3m, the signal length is determined to allow periodic determination. Otherwise, the signal length N is extended to three interference periods. The values ​​of the autocorrelation function at 2m and 3m are determined. If the autocorrelation function also has peaks at 2m and 3m, the interference period of the interference signal is determined to be m. Otherwise, it is determined that the interference signal does not have periodicity; Step 3: Perform Fourier transform on the interference signal through a spectrum analyzer to obtain a spectrum that displays the signal in a graphical manner. Mark the discrete spectral lines of the spectrum in the graphical spectrum, record the minimum value in each group of marks as the fundamental frequency f0, and then compare the other marks with the fundamental frequency. If the spectrum data of other marks are all integer multiples of the fundamental frequency data, then the spectrum marked as the fundamental frequency is determined to be the fundamental frequency, and the period of the interference signal is determined. Step 4: If the autocorrelation function also has peaks at 2m and 3m, and the spectrum data of other markers are integer multiples of the baseband data, it is determined that the interference signal has periodicity.

6. The anti-interference method based on the dual-frequency communication mode according to claim 1, characterized in that: The anti-interference strategy for periodic interference signals is as follows: Step 1: If the interference signal is periodic and the fundamental frequency of the interference signal is f0, adjust the frequency of the normal signal to the intermediate value of the frequencies of the two interference signals. After the adjustment is completed, detect the interference ratio IR1 of the interference signal to the normal signal. If the preset signal interference ratio threshold IR max > IR1, it means that the interference signal does not interfere with the normal signal; if the preset signal interference ratio threshold IR max < IR1, it is determined that the interference signal still interferes with the normal signal, and the avoidance of the interference signal interference is carried out; Step 2: randomly set g1 signal receiving points that are the same as the communication signal receiving point near the communication signal receiving point, set the frequency of the set signal receiving point, and set the frequency within the frequency band permitted by the communication system and at a frequency point that is separated from the interference signal frequency. Then, detect the signal strength of the signal receiving point through a spectrum scanner, and arrange the g1 signal receiving points set later in order of signal strength from weak to strong. Select g2 signal receiving points at the end of the arrangement, and merge the signal strengths. The selected number g2 is twice the number of interference signal receiving points, and the number g1 is greater than twice g2. Step 3: Receive signals from two frequency points at the same time, and use maximum ratio combining technology to jointly process them. According to the strength and quality of the two frequency point signals, different weights are assigned for merging; the signal strength of frequency point one is preset to be XH1, and the signal strength of frequency point two is XH2. The signal strength data after maximum ratio combining is XH=a1*XH1+a2*XH2, where a1 and a2 are weight coefficients; if the signals of two frequency points are both interfered with, select signals of four or more frequency points, and then merge them in pairs, and select the two with the strongest signal strength after merging and assign them to the corresponding two frequency points; if the signal of only one frequency point is interfered with, then the signals of two or more frequency points are merged in pairs.

7. The anti-interference method based on the dual-frequency communication mode according to claim 1, characterized in that: The anti-interference strategy for non-periodic interference signals is as follows: Step 1: Preset the filter coefficients and the filter input signal, then calculate the value of the output signal according to the input signal through the adaptive filtering formula, and calculate the difference between the input signal and the expected signal, and record the difference as the error E(r), where r is the sample number; Step 2: Set the step size factor to μ and initialize the filter coefficient to C(0). For each input signal sample A(r), the output signal can be calculated according to the current filter coefficient C(r) according to the formula for calculating the output signal. Then, the error between the input signal and the expected signal is calculated. According to the error and the input signal, the output signal is calculated according to the formula C i (r+1)=C i (r)+2μ*E(r)*A(ri), update the filter coefficient to C(r+1); Step 3: Repeat the operations of steps 1 and 2, and continuously process new input signal samples so that the filter coefficients continuously adapt to the interference environment; the preset error value is ε, and when the error E(r) between the input signal and the expected signal = ε, stop the iterative operation.

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