An aircraft monitoring method and device based on vibration sensors

Abstract

The present invention discloses a method and device for monitoring an aircraft based on a vibration sensor. The method converts the vibration signal received by the vibration sensor from the time domain to the frequency domain, selects the frequency corresponding to the amplitude peak for sampling to obtain sampling data, and then selects the sampling data that matches the signal characteristics of the aircraft to obtain the time-frequency parameters of the vibration signal. The center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the vibration sensor are obtained through the time-frequency parameters to monitor the state of the aircraft. By determining the signal characteristics of the aircraft corresponding to air traffic events and screening and matching the corresponding signal data from the vibration signals received by the vibration sensor, the present invention can accurately monitor and quantify the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the vibration sensor, thereby realizing real-time monitoring of the flight state of the aircraft.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft flight state monitoring, and particularly to an aircraft monitoring method and device based on vibration sensors. Background Art

[0002] In the prior art, the flight state of an aircraft such as flight trajectory, flight speed, and distance relative to a specific location on the ground is generally monitored by radar monitoring or "Automatic Dependent Surveillance - Broadcast (ADS - B)". However, the radar monitoring method may have monitoring blind spots for low - altitude flying aircraft and stealth aircraft, etc.; while the principle of the ADS - B flight tracking system is based on the aircraft actively broadcasting its identity, altitude, speed, coordinate and other flight information parameters at a specific frequency band continuously, which is essentially a passive monitoring. If active monitoring is to be carried out on an aircraft, the placement locations of both the radar detection method and the ADS - B flight tracking system will be limited, and low - altitude flying or stealth flying aircraft cannot be monitored, resulting in a narrow application scenario.

[0003] In the field of seismology, vibration sensors such as seismographs are widely set up globally. The vibration sensors in the seismograph observation array can record various ground motion signals, including seismic events, the interaction between wind, vegetation and buildings, road rail transit, and signals generated by the coupling of air and the ground surface. However, in traditional seismic research, the impact of air traffic events on seismic waveforms is often ignored, and there is no research on the relationship between air traffic events and vibration wave signals, resulting in vibration sensors not being well applied to the field of aircraft monitoring.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the Invention

[0005] In view of the deficiencies of the above - mentioned prior art, the purpose of the present invention is to provide an aircraft monitoring method based on vibration sensors to solve the problem that vibration sensors in the prior art cannot be applied to the field of aircraft monitoring, resulting in the monitoring of aircraft being restricted by the scenario.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention discloses an aircraft monitoring method based on vibration sensors, wherein the method includes:

[0008] Obtain a first vibration signal received by a first vibration sensor;

[0009] Convert the first vibration signal from the time domain to the frequency domain, select the frequency corresponding to the amplitude peak for sampling, and obtain first sampling data;

[0010] Select the first sampled data that matches the signal characteristics of the aircraft, and obtain the first time-frequency parameters corresponding to the first sampled data, where the aircraft signal characteristics include a first signal, a second signal, and a third signal connected in sequence, the first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the aircraft signal characteristics is greater than 100 seconds;

[0011] According to the first time-frequency parameters, obtain the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

[0012] In one embodiment, the obtaining the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor according to the first time-frequency parameters to monitor the state of the aircraft includes:

[0013] Determine an aircraft state model for the center frequency, flight speed, shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor, and the time when the aircraft emits the first vibration signal;

[0014] According to the Doppler effect principle, determine the relationship between the received frequency and the observed frequency of the first vibration signal by the first vibration sensor;

[0015] Based on the relationship between the received frequency and the observed frequency, according to the first time-frequency parameters, iterate the aircraft state model to obtain the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

[0016] In one embodiment, the method further includes:

[0017] Obtain the second vibration signal received by the second vibration sensor;

[0018] Obtain second sampled data according to the second vibration signal, select the second sampled data that matches the signal characteristics of the aircraft, and obtain the second time-frequency parameters corresponding to the second sampled data;

[0019] Based on the first time-frequency parameters, the second time-frequency parameters, and the positional relationship between the first vibration sensor and the second vibration sensor, obtain the flight trajectory direction of the aircraft.

[0020] In one implementation, obtaining the flight trajectory direction of the aircraft based on the first time-frequency parameter, the second time-frequency parameter, and the positional relationship between the first vibration sensor and the second vibration sensor includes:

[0021] Based on the first time-frequency parameter and the second time-frequency parameter, obtain the time difference between the first vibration sensor and the second vibration sensor receiving the same vibration signal;

[0022] According to the time difference, the flight speed, and the positional relationship between the first vibration sensor and the second vibration sensor, obtain the flight trajectory direction of the aircraft.

[0023] In one implementation, the method further includes:

[0024] Obtain the third vibration signal received by the third vibration sensor;

[0025] According to the third vibration signal, obtain third sampling data, select the third sampling data that matches the signal characteristics of the aircraft, and obtain the third time-frequency parameter corresponding to the third sampling data;

[0026] Based on the second time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the second vibration sensor, and based on the third time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the third vibration sensor;

[0027] According to the shortest distance of the flight trajectory relative to the first vibration sensor, the shortest distance of the flight trajectory relative to the second vibration sensor, the shortest distance of the flight trajectory relative to the third vibration sensor, and the flight trajectory direction, obtain the flight height of the aircraft.

[0028] In one implementation, the first vibration sensor, the second vibration sensor, and the third vibration sensor are all sensor arrays composed of multiple sub-sensors, and the spacing between adjacent sub-sensors in the sensor array is less than the wavelengths of the first vibration signal, the second vibration signal, and the third vibration signal.

[0029] In one implementation, the method further includes:

[0030] Translate and superimpose the multiple vibration signals received by the sensor array, and obtain the time difference corresponding to the strongest wave train signal after superimposition;

[0031] Based on the time difference and the spacing between adjacent sub-sensors in the sensor array, obtain the azimuth angle and elevation angle of the aircraft.

[0032] In one embodiment, the method further includes:

[0033] Fitting the first sampled data on a time-frequency diagram to obtain the number of features in the fitted image that conform to the aircraft signal characteristics;

[0034] When the number of features is 0, it is determined that no aircraft has flown by;

[0035] When the number of features is 1, it is determined that the aircraft is an airplane;

[0036] When the number of features is greater than 1, it is determined that the aircraft is a helicopter.

[0037] A second aspect of the present invention provides an aircraft monitoring device based on a vibration sensor, which includes:

[0038] A signal acquisition module for acquiring a first vibration signal received by a first vibration sensor;

[0039] A signal sampling module for converting the first vibration signal from the time domain to the frequency domain, selecting the frequency corresponding to the amplitude peak for sampling to obtain first sampled data;

[0040] A signal processing module for selecting the first sampled data that matches the aircraft signal characteristics to obtain first time-frequency parameters corresponding to the first sampled data, where the aircraft signal characteristics include a first signal, a second signal, and a third signal connected in sequence, the first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the aircraft signal characteristics is greater than 100 seconds;

[0041] An aircraft status monitoring module for obtaining the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor according to the first time-frequency parameters to monitor the status of the aircraft.

[0042] A third aspect of the present invention further provides an intelligent terminal, where the intelligent terminal includes a memory and more than one processor; the memory stores more than one program; when the processor runs the program, it executes the aircraft monitoring method based on a vibration sensor as described in any one of the above.

[0043] In summary, the present invention discloses a method and device for monitoring an aircraft based on a vibration sensor. The method converts the vibration signal received by the vibration sensor from the time domain to the frequency domain, selects the frequency corresponding to the amplitude peak for sampling to obtain sampling data, and then selects the sampling data that matches the signal characteristics of the aircraft to obtain the time-frequency parameters of the vibration signal. The center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the vibration sensor are obtained through the time-frequency parameters to monitor the state of the aircraft. By determining the signal characteristics of the aircraft corresponding to air traffic events and screening and matching the corresponding signal data from the vibration signals received by the vibration sensor, the present invention can accurately monitor and quantify the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the vibration sensor, thereby realizing real-time monitoring of the flight state of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flowchart of the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0045] Figure 2 It is a schematic diagram of using a single vibration sensor to monitor the flight state of an aircraft in an embodiment of the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0046] Figure 3 It is a schematic diagram of using two vibration sensors to monitor the flight state of an aircraft in an embodiment of the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0047] Figure 4 It is a schematic diagram of using a dense sensor array to monitor the flight state of an aircraft in an embodiment of the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0048] Figure 5 It is an amplitude-time graph of the vibration signal received in the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0049] Figure 6 It is a frequency-time graph of the vibration signal received in the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0050] Figure 7 It is a comparison schematic diagram of the frequency-time graphs of a shipping airliner and a helicopter monitored in the method for monitoring an aircraft based on a vibration sensor according to the present invention.

[0051] Figure 8 It is a fitting simulation schematic diagram after receiving and sampling the vibration signal in the method for monitoring an aircraft based on a vibration sensor according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The present invention provides a method and device for monitoring an aircraft based on a vibration sensor. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] It should be noted that unless otherwise specifically defined in the text for articles, "a" and "the" can generally refer to a single or plural. If there are descriptions such as "first", "second", etc. in the embodiments of the present invention, such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first", "second" can explicitly or implicitly include at least one of such features. Additionally, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0054] Seismographs are widely distributed globally to monitor seismic waves and provide earthquake early warnings. The observational data received by seismographs are basically all public, but in the prior art, no applications other than earthquake prediction have been developed for this observational data, resulting in the above-mentioned public data being underutilized and causing resource waste. The present invention provides a method and device for monitoring an aircraft based on a vibration sensor. By using a vibration sensor, especially a seismograph sensor, to receive vibration signals, and then determining the aircraft signal characteristics corresponding to air traffic events, and screening and matching the corresponding signal data from the vibration signals received by the vibration sensor, the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the vibration sensor can be accurately monitored and quantified, thereby realizing the real-time monitoring of the flight state of the aircraft. In this way, by combining the signal analysis technology in the earthquake field with the aircraft flight state monitoring technology in the air traffic field, the application scenario is effectively expanded, which is beneficial to market promotion.

[0055] Specifically, in the method for monitoring an aircraft based on a vibration sensor of the present invention, the data is sourced from publicly available global seismograph observational data, or by setting up an observation station in the planned monitoring area and installing a vibration sensor in the observation station to record continuous vibration signals, such as continuous seismic waveforms. The waveform data recorded in this way not only contains signals of natural earthquakes, but also includes vibration signals generated by various human activities, such as vibration signals of air traffic events, etc. These signals are jointly coupled to form the continuous waveform data recorded by the observation network. By setting up different observation stations, it is possible to monitor different parameters of the flight state of the aircraft, such as Figure 2The figure shows a schematic diagram of the single-station method for setting up an observation station to monitor the flight speed of an aircraft, the center frequency of the aircraft, and the shortest distance from the flight trajectory of the aircraft to the vibration sensor. The center frequency of the aircraft is generally generated by the operation of the aircraft engine. One aircraft corresponds to one center frequency, while for a helicopter, there are multiple center frequencies corresponding to the engine and the propeller. As Figure 3 The figure shows a schematic diagram of the double-station method for setting up two observation stations to monitor the flight trajectory direction of the aircraft. As Figure 4 The figure shows a schematic diagram of the dense array method for setting up multiple sub-sensors. By observing the network and performing waveform beamforming analysis, the azimuth and elevation angles of the aircraft can be monitored to determine the specific position of the aircraft. Optionally, in the aircraft monitoring method based on vibration sensors of the present invention, a seismograph vibration sensor can be used, or a sound vibration sensor or a distributed fiber optic vibration sensor can be used, etc. The existing vibration sensor resources are utilized to monitor air traffic events, thereby realizing real-time and accurate monitoring of the flight state of the aircraft.

[0056] After obtaining the vibration signal by using the vibration sensor, as Figure 5 and Figure 6 shown, the observed original waveform data is the relationship between amplitude and time. After Fourier transform from the time domain to the frequency domain, instant time-frequency analysis is performed to monitor and analyze air traffic events such as airplanes and helicopters in real time. The waveform data is converted from the time domain to the frequency domain, and the frequency corresponding to the amplitude peak is selected for sampling to obtain sampling data. If there is a signal corresponding to an air traffic event (i.e., the flight behavior of the aircraft) in the received vibration signal, then the aircraft signal characteristics corresponding to the air flight event can be clearly obtained by fitting the sampling data on the frequency-time diagram. As Figure 6 and Figure 8 shown, the starting point of the aircraft signal characteristics on the frequency-time diagram is a relatively flat high-frequency signal, then the frequency decreases gently, and finally ends with a relatively flat low-frequency signal. The whole process lasts for hundreds of seconds. Through the aircraft signal characteristics, the vibration signal related parameters matching the flight state of the aircraft can be quickly screened, so that the flight state of the aircraft can be determined, and real-time and accurate monitoring of the flight state of the aircraft can be realized.

[0057] Furthermore, the type of the aircraft can be determined by using the aircraft signal characteristics. As Figure 7 shown, Figure 7 in (a) of Figure 7In (b), the aircraft signal features corresponding to the helicopter are multiple relatively parallel aircraft signal features. This is because during the flight of a commercial airliner, the central frequency is only that of the engine, so there is only one aircraft signal feature; while the vibration sources of a helicopter are more complex and often include aircraft signal features corresponding to the engine and the propeller. The characteristics of these signals are similar, and there are only differences in the magnitude of the frequency due to the differences in the frequency sources, thus forming multiple relatively parallel aircraft signal features. In this way, the type of the aircraft can be identified through the aircraft signal features, and the rapid classification of the aircraft can be completed.

[0058] Further, after screening and obtaining the sampling data that matches the aircraft signal features of the aircraft, the time-frequency parameters corresponding to the sampling data are obtained, and a parameter equation is established using the principle of the Doppler effect to simulate and fit the time-frequency parameters, so as to obtain parameters such as the distance, flight speed, and central frequency of the aircraft. The specific process includes:

[0059] First, according to the principle of the Doppler effect, when a moving source emits a wave signal, the frequency of the wave received by the vibration sensor will change, and this change follows the formula:

[0060]

[0061] Among them, f0 is the central frequency of the moving source, that is, the emission frequency of the aircraft when the distance between the aircraft and the vibration sensor is the shortest. At this position, the relative velocity of the aircraft in the direction of the line connecting it and the vibration sensor is zero. V0 is the flight speed of the aircraft. Here, it is assumed that the aircraft makes an approximate uniform linear motion as shown in Figure 2 shown; l is the shortest distance between the aircraft and the vibration sensor, that is, the distance obtained by drawing a perpendicular line from the vibration sensor to the flight trajectory of the aircraft; c is the propagation speed of sound waves in the air (~343m / s). t is the time when the aircraft flies to a certain point. At time t, the sound wave emitted by the aircraft is received by the vibration sensor at time t′, and t′ can be expressed as:

[0062]

[0063] Considering t′>t, from equation (2), we can obtain:

[0064]

[0065] Considering any reference time t′0 and substituting it into equation (3), we can get:

[0066]

[0067] (4) There are 4 unknown model parameters in the equation, denoted as m0 = [f0 v0 l t′0] T, as the aircraft state model, the fluctuation frequency f(t′) = f(m0; t′) received by the vibration sensor can be obtained from equations (1) and (4); the fluctuation frequency observed by the vibration sensor is expressed as f ob (t′). By establishing the initial model parameter m0, the final solution of the model parameter can be iteratively obtained by the following formula:

[0068] m = m0+(G T G) -1 G T [f ob (t′)-f(m0; t′)],#(5a)

[0069]

[0070] When sampling after converting the vibration signal from the time domain to the frequency domain, select the frequency corresponding to the amplitude peak, and the sampling points matching the aircraft signal characteristics are as shown by the black dots in Figure 8 . The black curve is the time-frequency curve obtained by model fitting, which is the flight signal characteristic of the aircraft corresponding to the currently received vibration signal. By fitting and iterating, the center frequency of the aircraft corresponding to this vibration signal can be obtained as 130.1938 Hz, the flight speed is 108.9854 m / s, and the shortest distance between the flight trajectory of the aircraft and the vibration sensor is 4605.579 m. In this way, through the time-frequency parameters, combined with the aircraft state model, according to the Doppler effect principle, the relationship between the received frequency and the observed frequency of the vibration signal can be obtained, and then the center frequency, flight speed, the shortest distance of the flight trajectory relative to the vibration sensor, and the reference time of the aircraft can be iteratively solved, so as to realize the real-time monitoring of the flight state of the aircraft.

[0071] Furthermore, when the aircraft is a helicopter, taking the logarithm of both sides of equation (1) simultaneously, we can get:

[0072]

[0073] It can be seen that for a helicopter, even if there are different vibration sources, only the first term of equation (5a) is different in the received time-frequency spectrum, and the second term is the same. This is reflected in the time-frequency diagram shown in (b) of Figure 7 as multiple curves with the same shape. Therefore, for each observed curve, using the method of equations (1)-(5) can well fit the time-frequency signal of the helicopter, and obtain multiple center frequencies and the unique flight speed and the shortest distance of the flight trajectory relative to the vibration sensor.

[0074] Further, after determining the flight speed of the aircraft and the distance from the relative vibration sensor using the single - station method, the flight direction of the aircraft can be determined by the double - station method (i.e., setting two vibration sensors at different positions).

[0075] Let the reference point on the flight trajectory of the aircraft be The direction vector be The reference time be \(t'_0\). As Figure 3 shown, there are two vibration sensors \(S_1\) and \(S_2\) at different positions. At \(t' = t'\) 01 time, the first vibration sensor \(S_1\) receives the wave signal emitted by the aircraft at point \(A_1\). Substituting into equation (4) gives: This means that it takes time for the wave of the vibration signal to propagate from \(A_1\) to \(S_1\) where \(l_1\) is the shortest distance between the first vibration sensor and the flight trajectory of the aircraft, \(l_2\) is the shortest distance between the second vibration sensor and the flight trajectory of the aircraft, \(c\) is the propagation speed of sound waves in the air (calculated at 343 m / s), and \(v_0\) is the average value of the flight speeds of the aircraft monitored by the first vibration sensor and the second vibration sensor respectively. Therefore, it can be calculated that: And:

[0076]

[0077] Similarly, for the second vibration sensor \(S_2\), it can also be calculated that:

[0078]

[0079] Subtracting equations (7) and (8) gives:

[0080]

[0081] Let the positions of the first vibration sensor \(S_1\) and the second vibration sensor \(S_2\) be represented by vectors and respectively, then As Figure 3 shown, according to the geometric relationship, it can be obtained that:

[0082]

[0083]

[0084] Substituting \(t_2 - t_1=\vert A_1S_1\vert / v_0\) gives:

[0085]

[0086] The reference time t' in the formula 01 and t' 02 can be inversely obtained from the observed data according to formula (5a); is the direction vector of the flight trajectory of the aircraft, satisfying e x 2 +e y 2 +e z 2 = 1. Therefore, there are only two independent unknown parameters. So, the direction vector of the aircraft's flight trajectory can be obtained by using the two-station method with two vibration sensors and thus the flight trajectory direction of the aircraft can be obtained.

[0087] Furthermore, by using the three-station method with one more vibration sensor, the three-dimensional coordinate position of the aircraft can be further determined.

[0088] The coordinate vector of the reference point on the flight trajectory and the relationship of l can be obtained by the Pythagorean theorem:[[]]

[0089]

[0090] The coordinate origin is selected on the ground; in the formula refers to the coordinate vector of the first vibration sensor, refers to the coordinate vector of the second vibration sensor, refers to the coordinate vector of the third vibration sensor, which is a known quantity that can be obtained from the positional relationship of the three vibration sensors; l1 is the shortest distance between the first vibration sensor and the flight trajectory of the aircraft, l2 is the shortest distance between the second vibration sensor and the flight trajectory of the aircraft, and l3 is the shortest distance between the third vibration sensor and the flight trajectory of the aircraft, all of which can be obtained by iteration according to formula (5a); is the direction vector corresponding to the flight trajectory direction, which can be obtained from formula (11). Therefore, according to formula (12), the coordinate of the reference point of the flight trajectory can be obtained whose vertical component is the flight height of the aircraft. Combining with the trajectory direction vector the navigation trajectory of the aircraft can be obtained.

[0091] Furthermore, in order to further improve the monitoring accuracy, a dense sub-array composed of multiple sub-sensors as shown in Figure 4 can also be used as the first vibration sensor, the second vibration sensor, and the third vibration sensor. By setting the vibration sensors as an observation network of a dense sub-array and performing waveform beamforming analysis on the observations of the array, the waveform signal can be enhanced and the propagation direction of the wave field, that is, the position direction where the aircraft is located, can be obtained.

[0092] Specifically, when setting up the dense sub-array, the spacing between adjacent sub-sensors needs to be less than the wavelength of the detected sound wave; otherwise, there will be an uncertainty in the period multiple of the phase difference. In the aircraft monitoring method based on vibration sensors of the present invention, based on the 0 - 200 Hz of the main frequency band range of airplanes and helicopters, it is required that the spacing between each sub-sensor in the dense sub-array is less than ~1.7 meters.

[0093] The waveform bunching method is often used in seismology for earthquake location and can also be applied to aircraft location here. Its principle is as Figure 4 shown. Assume that the azimuth angle of the aircraft, that is, the angle between the projection of the line connecting the aircraft and the sub-sensor on the horizontal plane and the line connecting adjacent sub-sensors, is θ, and the elevation angle of the aircraft, that is, the angle between the line connecting the aircraft and the sub-sensor and the horizontal plane, is φ, and the spacing between adjacent sub-sensors in the vibration sensor is d0. Then the time difference between the wave trains received by sub-sensor A and sub-sensor C is

[0094]

[0095] Translate the two groups of later wave train signals, and then superimpose the wave trains. When the superimposed wave train signal is the strongest, the time difference corresponding to the strongest wave train signal can be obtained. Then, combining the time difference and the spacing between adjacent sub-sensors, the combination of the azimuth angle θ and the elevation angle φ of the corresponding aircraft can be obtained, thereby further determining the flight state of the aircraft. Replacing the first vibration sensor, the second vibration sensor, and the third vibration sensor with a sensor array composed of multiple sub-sensors can improve the monitoring accuracy without affecting the monitoring of the aircraft flight state, thereby realizing the accurate monitoring of aircraft-related air traffic events and the solution of trajectory parameters, providing technical support for air traffic management and safety.

[0096] Through the aircraft monitoring method based on vibration sensors of the present invention, the vibration signal received by the vibration sensor is converted from the time domain to the frequency domain, the frequency corresponding to the amplitude peak is selected for sampling to obtain sampling data, and then the sampling data matching the signal characteristics of the aircraft is selected to obtain the time-frequency parameters of the vibration signal. Through the time-frequency parameters, the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the vibration sensor are obtained to monitor the state of the aircraft. By determining the signal characteristics of the aircraft corresponding to the air traffic event, the corresponding signal data is screened and matched from the vibration signal received by the vibration sensor, so as to accurately monitor and quantify the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the vibration sensor, thereby realizing the real-time monitoring of the flight state of the aircraft.

[0097] As Figure 1 shown, the aircraft monitoring method based on vibration sensors of the present invention includes the steps:

[0098] S100. Obtain the first vibration signal received by the first vibration sensor.

[0099] Optionally, the first vibration sensor may be an existing seismograph vibration sensor, a deployed acoustic sensor, a distributed optical fiber sensor, etc., or a vibration sensor specially set in the planned monitoring area.

[0100] Further, as Figure 1 shown, after step S100 of the aircraft monitoring method based on vibration sensors of the present invention, it includes:

[0101] S200. Convert the first vibration signal from the time domain to the frequency domain, select the frequency corresponding to the amplitude peak for sampling, and obtain the first sampling data.

[0102] Convert the first vibration signal from the time domain to the frequency domain through Fourier transform, and then select the frequency corresponding to the amplitude peak for sampling to obtain the first sampling data, so as to obtain as many sampling points as possible on the time-frequency diagram, which is convenient for subsequent fitting simulation.

[0103] Further, as Figure 1 shown, after step S200 of the aircraft monitoring method based on vibration sensors of the present invention, it includes:

[0104] S300. Select the first sampling data that matches the signal characteristics of the aircraft, and obtain the first time-frequency parameters corresponding to the first sampling data.

[0105] Since the original first vibration signal includes signals generated by various vibrations such as natural earthquake vibration signals, human activity vibration signals, and air traffic event vibration signals, it is necessary to extract the vibration signal corresponding to the aircraft through data analysis. Among them, the aircraft signal characteristics show very obvious characteristics on the time-frequency diagram, that is, the first signal, the second signal, and the third signal connected in sequence. As Figure 6 and Figure 7 shown, the first signal corresponds to a relatively flat high-frequency signal at the starting point, the second signal corresponds to the signal with a gentle decline in the middle frequency part, and the third signal corresponds to the relatively flat low-frequency signal at the last part. The first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the aircraft signal characteristics is greater than 100 seconds. By fitting the number of characteristics that conform to the aircraft signal characteristics in the image, the type of the aircraft can be determined. Among them, when the number of characteristics is 0, it is determined that no aircraft has flown by; when the number of characteristics is 1, it is determined that the aircraft is an airplane; when the number of characteristics is greater than 1, it is determined that the aircraft is a helicopter.

[0106] By fitting the first sampling data on a time-frequency diagram, sampling data conforming to the signal characteristics of the aircraft are determined, thereby screening out the first time-frequency parameters matching the vibration signals related to the aircraft. Then, the relevant flight states of the aircraft are obtained through simulation and fitting, realizing the monitoring of the flight states of the aircraft.

[0107] Further, as Figure 1 shown, after step S300, the aircraft monitoring method based on vibration sensors according to the present invention includes:

[0108] S400. According to the first time-frequency parameters, obtain the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

[0109] Since the aircraft moves relative to the first vibration sensor, there are differences between the observed frequency and the received frequency of the vibration signal for the first vibration sensor. Based on the differences between the observed frequency and the received frequency, and combined with the first time-frequency parameters, the aircraft state model can be iteratively determined, thereby obtaining the center frequency, the flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

[0110] Specifically, first determine the changes in the received frequency and the observed frequency of the first vibration signal received by the first vibration sensor due to the Doppler effect. Assuming that the aircraft moves in a uniform straight line and the propagation speed of sound in the air is taken as 343 m / s, the relationship between the time when the first vibration sensor receives the first vibration signal and the time when the aircraft actually emits the first vibration signal can be obtained. Then, combined with any reference time, the aircraft state model can be expressed as a model m0 = [f0 v0 l t′0] T containing 4 unknown model parameters, where f0 is the center frequency of the aircraft, v0 is the flight speed of the aircraft, l is the shortest distance between the aircraft and the vibration sensor, and t′0 is the reference time. Iteratively solving the parameters of the aircraft state model can obtain the center frequency, the flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

[0111] Furthermore, for a helicopter with multiple center frequencies, even if there are different vibration sources, the received time-frequency spectrum only differs in the center frequency, and the other items are the same. In the time-frequency diagram, this is reflected as multiple curves with the same shape. Therefore, by using the same method to process each observed curve, the time-frequency signal of the helicopter can be well fitted, and multiple center frequencies, as well as the unique flight speed and the shortest distance of the flight trajectory relative to the vibration sensor, can be obtained, so as to monitor the flight state of the helicopter in real time and accurately.

[0112] Furthermore, a second vibration sensor at a different position from the first vibration sensor is added to monitor the flight trajectory direction of the aircraft. Specifically, it includes the steps:

[0113] H100. Obtain the second vibration signal received by the second vibration sensor.

[0114] H200. Obtain second sampling data according to the second vibration signal, select the second sampling data that matches the signal characteristics of the aircraft, and obtain the second time-frequency parameters corresponding to the second sampling data.

[0115] H300. Based on the first time-frequency parameters, the second time-frequency parameters, and the positional relationship between the first vibration sensor and the second vibration sensor, obtain the flight trajectory direction of the aircraft.

[0116] Among them, first, based on the first time-frequency parameters and the second time-frequency parameters, according to the spatial geometric relationship and the already obtained flight speed of the aircraft, obtain the time difference between the first vibration sensor and the second vibration sensor receiving the same vibration signal; then, according to the time difference, the flight speed, and the positional relationship between the first vibration sensor and the second vibration sensor, according to the geometric relationship, the time difference can be expressed as a function of the position vector of the first vibration sensor, the position vector of the second vibration sensor, the flight speed of the aircraft, and the flight trajectory direction of the aircraft. For the direction vector of the flight trajectory of the aircraft satisfies e x 2 +e y 2 +e z 2 = 1. Therefore, when the time difference, the position vector of the first vibration sensor, the position vector of the second vibration sensor, and the flight speed of the aircraft are known, this function has only two independent unknown parameters. So, by setting the first vibration sensor and the second vibration sensor, the direction vector of the flight trajectory of the aircraft can be obtained Thus, the flight trajectory direction of the aircraft is obtained.

[0117] Further, a third vibration sensor at a different position from the first vibration sensor and the second vibration sensor is added, and the first vibration sensor, the second vibration sensor, and the third vibration sensor are not on the same straight line to monitor the flight trajectory direction of the aircraft. Specifically, it includes the steps:

[0118] M100. Obtain the third vibration signal received by the third vibration sensor.

[0119] M200. Obtain third sampling data according to the third vibration signal, select the third sampling data that matches the signal characteristics of the aircraft, and obtain the third time-frequency parameter corresponding to the third sampling data.

[0120] M300. Based on the second time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the second vibration sensor, and based on the third time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the third vibration sensor.

[0121] M400. Obtain the flight altitude of the aircraft according to the shortest distance of the flight trajectory relative to the first vibration sensor, the shortest distance of the flight trajectory relative to the second vibration sensor, the shortest distance of the flight trajectory relative to the third vibration sensor, and the flight trajectory direction.

[0122] Specifically, the relationship between the coordinate vector of the specific position of the aircraft in the three-dimensional coordinate system and the shortest distance of the flight trajectory relative to the first vibration sensor, the shortest distance of the flight trajectory relative to the second vibration sensor, and the shortest distance of the flight trajectory relative to the third vibration sensor can be obtained by the Pythagorean theorem. Through the three groups of data of the first vibration sensor, the second vibration sensor, and the third vibration sensor, the three-dimensional coordinates of the specific position of the aircraft can be obtained, so as to determine the flight altitude of the aircraft. Finally, combined with the direction vector the navigation trajectory of the aircraft can be obtained.

[0123] Further, in order to further improve the monitoring accuracy, the first vibration sensor, the second vibration sensor, and the third vibration sensor can also be set as a sensor array composed of multiple sub-sensors, and the distance between adjacent sub-sensors in the sensor array is less than the wavelengths of the first vibration signal, the second vibration signal, and the third vibration signal. In this way, by translating and superimposing the multiple vibration signals received by the sensor array, the time difference corresponding to the strongest wave train signal after superposition can be obtained, and then based on the time difference and the distance between adjacent sub-sensors in the sensor array, the azimuth angle and elevation angle of the aircraft can be obtained, and the specific flight state of the aircraft can be determined. By setting the sensor array, the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor with higher monitoring accuracy can be obtained through the first vibration sensor, the second vibration sensor, and the third vibration sensor, as well as the flight trajectory direction of the aircraft, the flight height of the aircraft, and the azimuth angle and elevation angle of the aircraft, so as to ensure real-time and accurate monitoring of the flight state of the aircraft.

[0124] Through the aircraft monitoring method based on vibration sensors of the present invention, the present invention can achieve accurate monitoring of air traffic events and solution of orbital parameters, providing important technical support for air traffic management and safety.

[0125] In one embodiment, the present invention also provides an aircraft monitoring device based on vibration sensors, including:

[0126] A signal acquisition module 500, configured to acquire a first vibration signal received by a first vibration sensor;

[0127] A signal sampling module 600, configured to convert the first vibration signal from the time domain to the frequency domain, select the frequency corresponding to the amplitude peak for sampling, and acquire first sampling data;

[0128] A signal processing module 700, configured to select the first sampling data that matches the signal characteristics of the aircraft, and acquire first time-frequency parameters corresponding to the first sampling data. The aircraft signal characteristics include a first signal, a second signal, and a third signal connected in sequence according to time sequence, the first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the aircraft signal characteristics is greater than 100 seconds; and

[0129] An aircraft state monitoring module 800, configured to obtain the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor according to the first time-frequency parameters, so as to monitor the state of the aircraft.

[0130] In one embodiment, the present invention further provides an intelligent terminal, where the intelligent terminal includes a memory and more than one processor; the memory stores more than one program; when the processor runs the program, it executes the aircraft monitoring method based on a vibration sensor as described in any one of the above.

[0131] In summary, the present invention discloses an aircraft monitoring method and device based on a vibration sensor. The method converts the vibration signal received by the vibration sensor from the time domain to the frequency domain, selects the frequency corresponding to the amplitude peak for sampling to obtain sampling data, and then selects the sampling data that matches the signal characteristics of the aircraft to obtain the time-frequency parameters of the vibration signal. The center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the vibration sensor are obtained through the time-frequency parameters to monitor the state of the aircraft. By determining the signal characteristics of the aircraft corresponding to the air traffic event and screening and matching the corresponding signal data from the vibration signals received by the vibration sensor, the present invention can accurately monitor and quantify the center frequency, flight speed, and the shortest distance of the flight trajectory of the aircraft relative to the vibration sensor, thereby realizing the real-time monitoring of the flight state of the aircraft.

[0132] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A monitoring method for an aircraft based on a vibration sensor, characterized in that, The method includes: Obtaining a first vibration signal received by a first vibration sensor; Converting the first vibration signal from the time domain to the frequency domain, selecting the frequency corresponding to the amplitude peak for sampling, and obtaining first sampling data; Selecting the first sampling data that matches the signal characteristics of the aircraft, and obtaining first time-frequency parameters corresponding to the first sampling data, where the aircraft signal characteristics include a first signal, a second signal, and a third signal connected in sequence, the first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the aircraft signal characteristics is greater than 100 seconds; Based on the first time-frequency parameters, obtaining the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

2. The method for monitoring an aircraft based on a vibration sensor according to claim 1, wherein The obtaining the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor based on the first time-frequency parameters to monitor the state of the aircraft includes: Determining an aircraft state model for the center frequency, flight speed, shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor, and the time when the aircraft emits the first vibration signal; Determining the relationship between the received frequency and the observed frequency of the first vibration signal by the first vibration sensor according to the Doppler effect principle; Based on the relationship between the received frequency and the observed frequency, according to the first time-frequency parameters, and in combination with the aircraft state model, obtaining the center frequency, flight speed, and shortest distance of the flight trajectory of the aircraft relative to the first vibration sensor to monitor the state of the aircraft.

3. The method for monitoring an aircraft based on a vibration sensor according to claim 2, wherein, The method further includes: Obtaining a second vibration signal received by a second vibration sensor; Obtaining second sampling data according to the second vibration signal, selecting the second sampling data that matches the signal characteristics of the aircraft, and obtaining second time-frequency parameters corresponding to the second sampling data; Based on the first time-frequency parameters, the second time-frequency parameters, and the positional relationship between the first vibration sensor and the second vibration sensor, obtaining the flight trajectory direction of the aircraft.

4. The method for monitoring an aircraft based on a vibration sensor according to claim 3, characterized in that, The obtaining the flight trajectory direction of the aircraft based on the first time-frequency parameters, the second time-frequency parameters, and the positional relationship between the first vibration sensor and the second vibration sensor includes: Based on the first time-frequency parameters and the second time-frequency parameters, obtaining the time difference between the first vibration sensor and the second vibration sensor receiving the same vibration signal; According to the time difference, the flight speed, and the positional relationship between the first vibration sensor and the second vibration sensor, obtaining the flight trajectory direction of the aircraft.

5. The method for monitoring an aircraft based on a vibration sensor according to claim 3, wherein The method further includes: Obtaining a third vibration signal received by a third vibration sensor; Obtain third sampling data according to the third vibration signal, select the third sampling data that matches the signal characteristics of the aircraft, and obtain the third time-frequency parameter corresponding to the third sampling data; Based on the second time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the second vibration sensor, and based on the third time-frequency parameter, obtain the shortest distance of the flight trajectory relative to the third vibration sensor; According to the shortest distance of the flight trajectory relative to the first vibration sensor, the shortest distance of the flight trajectory relative to the second vibration sensor, the shortest distance of the flight trajectory relative to the third vibration sensor, and the flight trajectory direction, obtain the flight altitude of the aircraft.

6. The flight vehicle monitoring method based on a vibration sensor according to claim 5, characterized in that The first vibration sensor, the second vibration sensor, and the third vibration sensor are all sensor arrays composed of multiple sub-sensors, and the distance between adjacent sub-sensors in the sensor array is less than the wavelengths of the first vibration signal, the second vibration signal, and the third vibration signal.

7. The aircraft monitoring method based on a vibration sensor according to claim 6, characterized in that, The method further includes: Translate and superimpose multiple vibration signals received by the sensor array, and obtain the time difference corresponding to the strongest wave train signal after superimposition; Based on the time difference and the distance between adjacent sub-sensors in the sensor array, obtain the azimuth angle and elevation angle of the aircraft.

8. The aircraft monitoring method based on a vibration sensor according to any one of claims 1-7, characterized in that, The method further includes: Fit the first sampling data on the time-frequency diagram, and obtain the number of features that conform to the signal characteristics of the aircraft in the fitted image; When the number of features is 0, it is determined that no aircraft has flown by; When the number of features is 1, it is determined that the aircraft is an airplane; When the number of features is greater than 1, it is determined that the aircraft is a helicopter.

9. An aircraft monitoring device based on a vibration sensor, characterized in that, Includes: A signal acquisition module for acquiring a first vibration signal received by a first vibration sensor; A signal sampling module for converting the first vibration signal from the time domain to the frequency domain, selecting the frequency corresponding to the amplitude peak for sampling, and obtaining first sampling data; A signal processing module for selecting the first sampling data that matches the signal characteristics of the aircraft, and obtaining the first time-frequency parameter corresponding to the first sampling data, wherein the signal characteristics of the aircraft include a first signal, a second signal, and a third signal connected in sequence, the first frequency corresponding to the first signal is greater than the third frequency corresponding to the third signal, the second frequency corresponding to the second signal gradually decreases to smoothly connect the first signal and the third signal, and the length of the signal characteristics of the aircraft is greater than 100 seconds; An aircraft state monitoring module for obtaining the center frequency, flight speed, and the shortest distance of the flight trajectory relative to the first vibration sensor according to the first time-frequency parameter, so as to monitor the state of the aircraft.

10. An intelligent terminal, characterized in that, The intelligent terminal includes a memory and more than one processor; the memory stores more than one program; when the processor runs the program, it executes the vibration sensor-based aircraft monitoring method according to any one of claims 1-8.

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