238 results about "Interference wave" patented technology

The invention provides a directional energy multi-target interference system based on an ultra-wideband phased array technology, and the system integrates signal perception, target recognition, interference signal generation and phased array control, so as to achieve the precise interference of an unmanned aerial vehicle cluster. The signal sensing module scans an airspace target through the ultra-wideband phased-array antenna array and obtains spectrum characteristics of a target signal. The target identification module analyzes signal features, identifies an individual target and predicts a motion track and a communication protocol of the individual target. And the phased array control module calculates and adjusts antenna beam forming parameters, and dynamically controls the radiation direction, phase and transmitting power of the antenna. The interference signal generation module generates a matched interference waveform based on the target communication protocol and the trajectory information. The ultra-wideband phased-array antenna array adopts a digital beam forming technology. According to the invention, efficient and accurate directional energy interference can be realized under multiple frequency bands, the confrontation capability of the unmanned aerial vehicle cluster is improved, and the method is suitable for defense tasks in electronic warfare and complex electromagnetic environments.

The invention provides a multi-target tracking and interference cooperation method and system based on a millimeter wave radar. The method comprises the following steps: firstly, acquiring an original detection signal in real time by using a millimeter-wave radar carried by an unmanned aerial vehicle, establishing a track correlation sequence of each moving target, extracting interference waveform characteristics formed by signal coupling among a plurality of moving targets in the original detection signal, and then, according to a spatial distribution parameter of the interference waveform characteristics, determining a track correlation sequence of each moving target; correcting the space-time continuity judgment rule of the trajectory correlation sequence, and finally outputting an anti-interference cooperative tracking result based on the corrected space-time continuity judgment rule. According to the technical scheme provided by the invention, the industry pain point that waveform distortion interference of the millimeter wave radar in a dense target scene cannot be eradicated is solved, and the error correlation rate in a dense formation scene is also reduced.

The invention belongs to the technical field of seismic exploration, and discloses a pre-stack gather optimization method based on multi-dimensional constraint dynamic time warping, which remarkably improves the space continuity and stability of a time shift field. According to the method, the time shift field which is smoother and more continuous in a three-dimensional space can be generated, and the common abnormal jump and unreasonable jitter of the time shift field in a conventional DTW method are effectively inhibited. This better conforms to the gradient characteristics of the geologic structure. Mismatching and processing illusion are effectively avoided, the adaptability of a complex structure area is improved, the global optimization capacity of the DTW algorithm is enhanced through multi-dimensional constraint, and the phenomenon that different horizons or effective waves are wrongly matched with interference waves due to local waveform complexity or noise interference is reduced. Therefore, common processing illusions such as event dislocation and local distortion in a conventional DTW method can be remarkably reduced.

The invention discloses a line tower grounding resistance intelligent detection system based on a TMR sensor technology, relates to the technical field of resistance detection, and solves the problem that a resistance signal is easily interfered by other signals or is influenced by temperature. According to the invention, superposition verification is carried out on waveforms of a resistance signal and an interference signal through a signal feature verification end, matching analysis of an extreme value segment and a virtual waveform is combined, an abnormal wave band and an interference source are accurately locked, and a reliable basis is provided for subsequent filtering; based on the peak point spacing (wavelength) and the transmission rate of the interference waveform, the interference frequency is calculated and a frequency interval is generated, so that an operator is supported to pertinently set filtering parameters, and specific frequency interference is effectively filtered out; by comparing the change characteristic ratio of the amplitude sequence to the temperature sequence, the response rule of the resistance value of the resistor changing along with the temperature is monitored in real time; and when the characteristic ratio does not decrease progressively according to the expected trend, a temperature change abnormal signal is triggered quickly.

The invention provides a control method for automatically collecting and eliminating target infrared characteristics, and relates to the technical field of target infrared characteristic elimination, and the method comprises the steps: obtaining real-time target and environment infrared data of a target of which the infrared characteristics are to be eliminated, carrying out the noise reduction processing, and obtaining continuous infrared spectrum data through spectrum integration; according to each environment background temperature, temperature adjustment is performed on each target surface, wavelet transform is performed on infrared spectrum data to obtain the temperature rise characteristic of the target, parameter optimization is performed on temperature adjustment, and region classification is performed on the adjusted target region to obtain a target region classification result. And carrying out smooth temperature adjustment on the classification areas exceeding the judgment threshold according to the temperature of the centers of the classification areas, calculating the phase, frequency and amplitude of an interference radiation spectrum according to the difference value between the real-time infrared radiation distribution data of the target and the environment and the position of a radiation interference source, adjusting interference waves, and eliminating the infrared characteristics of the target according to the interference principle.

The invention relates to the technical field of gasoline detection, in particular to a near infrared spectrum interference correction method and a near infrared spectrum interference correction system for vehicle gasoline detection. During vehicle gasoline near infrared spectrum correction, near infrared spectrum data of interference components in gasoline are collected, and characteristic wave bands of the interference components are analyzed; then whether the characteristic wave bands of the target component and the interference component coincide or not is judged to determine candidate interference wave bands, different interference correction methods are determined according to the interference indexes of the corresponding candidate interference wave bands, that is, different interference correction methods are adopted for different candidate interference correction wave bands, and the pertinence and accuracy of interference correction are improved.

The invention provides a silicon carbide MOS drive control chip overcurrent protection method and device, and the method comprises the steps: setting a forward sampling channel and a reverse sampling channel at a source sampling resistor, setting different sampling time windows for different sampling channels, carrying out the peak shifting setting of the time windows of the double sampling channels, and carrying out the peak shifting setting of the time windows of the double sampling channels, thereby achieving the overcurrent protection of a silicon carbide MOS drive control chip. The time period with the strongest common-mode interference can be avoided; meanwhile, the switching speed of the silicon carbide MOS device is mapped into a theoretical common-mode interference waveform, and the waveform and a bidirectional sampling signal are synthesized, so that a common-mode interference component in the sampling signal can be accurately separated, and the synthesized current signal is more accurate; on the basis, current signals are compensated by combining on-resistance change caused by junction temperature change, and overcurrent protection is carried out by adopting a graded protection strategy. According to the method, the influence of common-mode interference on current sampling is effectively overcome through peak shifting design on sampling channel time and common-mode interference separation based on switching speed.

The invention discloses a signal system intelligent identification and smart interference method and system, and belongs to the technical field of communication countermeasure, and the method comprises the steps: collecting IQ signals of different signal systems; constructing and training a multi-layer perceptron neural network model based on the acquired IQ signals of different signal systems; acquiring an IQ signal of a target object terminal in real time, and inputting the acquired IQ signal into the trained multilayer perceptron neural network model to obtain a signal system of the target object terminal; executing a signal synchronization process of a system corresponding to the target object terminal, and obtaining a time-frequency parameter of signal transmission; and generating a specific interference waveform according to the time-frequency parameter, and sending the specific interference waveform to a target object terminal. According to the method, the signal system is identified by combining an artificial intelligence method, the interference waveform is generated according to the characteristics of the signal system, the method has the characteristics of low interference energy loss, high concealment and strong pertinence, and intelligent flexible interference on star chain signals or public mobile communication is realized.

The invention provides a multi-sensor data fusion method and system based on an intelligent pod. According to the method, a radiation data flow of an intelligent pod multispectral sensor in an electromagnetic interference field is collected; based on the data, the quantitative attenuation coefficient of the radiation value of each wave band in the interference field is calculated by using a radiation transfer equation. And generating a directional beam of the phased-array antenna by using the coefficient, and scanning a target area to obtain echo data. And finally, performing joint sparse representation on the original radiation data stream and the target echo data to generate a fusion result. The invention discloses multi-sensor data fusion based on an intelligent pod. According to the method, the anti-interference wave beam scanning target is dynamically generated by quantifying the attenuation of electromagnetic interference on radiation of each wave band, and the sensing performance of the intelligent pod in a complex electromagnetic environment is improved by combining the joint sparse representation and fusing the multi-source data.

The invention relates to the technical field of radio navigation and countering, and particularly discloses an unmanned aerial vehicle interference system and device based on phased array radar direction finding. The system comprises a phased array radar direction finding module, an environment electromagnetic propagation characteristic modeling module, an interference beam dynamic planning module and a digital beam forming interference module. Through constructing a three-dimensional electromagnetic propagation model and based on propagation loss and a multipath effect predicted by the model, a beamforming weight used for pre-compensating environmental influence is optimized and calculated, and finally an interference antenna array is driven to radiate an intelligent beam subjected to environmental pre-compensation, so that high-intensity interference is formed at an actual physical position of a target unmanned aerial vehicle, and the target unmanned aerial vehicle is subjected to environmental pre-compensation. Direction finding errors are overcome, and interference efficiency and electromagnetic compatibility are improved.

The invention provides an intelligent anti-interference beam forming method based on dynamic prediction of an interference coming direction, and belongs to the crossing field of array signal processing and artificial intelligence. The method comprises the following steps: firstly, constructing an interference coming direction prediction model based on an autonomous attention full-connection network, and training the prediction model by using interference coming direction historical observation data; then, the trained prediction model is used for obtaining the interference coming direction of the next moment, an objective function is constructed in combination with the interference pointing requirement, an improved particle swarm method is used for forming the phase of each array element in the array, and an anti-interference wave beam is formed; and finally, along with the dynamic change of the coming direction of the interference, the coming direction of the interference is predicted again, an anti-interference beam is formed, and the dynamic intelligent anti-interference capability is realized. According to the method, the interference coming direction rule is extracted by using the interference coming direction historical data and prediction is realized, and intelligent interference beam forming in combination with the prediction result and the improved particle swarm method is realized.

This user device is for a 5G mobile communication system comprising memory and a processor. The user device performs a beam sweep using a resource block allocated by a base station, acquires information based on the noise intensity of an interference wave measured by an adjacent user device as a result of performing the beam sweep, and determines a beam to be used on the basis of information regarding an interfering beam.

The invention provides a seismic trace gather far offset energy preserving processing method, which comprises the following steps of: 1, decompiling field seismic data, and performing first arrival picking and trace gather extraction processing; 2, performing high-order dynamic correction processing on the extracted gather data to improve the influence of conventional dynamic correction stretching on the far offset; step 3, performing space-time variation cutting on gather first arrival waves and interference waves by adopting control points; step 4, performing offset resolution improvement processing on the gather data, and further improving the frequency dispersion problem of the far-offset data; and step 5, carrying out deconvolution, superposition and migration processing on the far-offset information preserving gather to obtain far-offset energy preserving seismic result data. According to the seismic trace gather far-offset energy maintaining processing method, recovery and maintenance of far-offset energy in seismic trace gather data can be realized, the imaging quality of seismic data of middle and shallow layers is improved, and recovery and maintenance of far-offset information are realized.

To suitably control the influence of cross-link interference.SOLUTION: User equipment is a user equipment of a 5G mobile communication system that includes a memory and a processor, performs beam sweeping using resource blocks allocated by a base station, obtains information based on the noise intensity of interference waves measured by adjacent user equipment as a result of performing the beam sweeping, and determines a beam to use on the basis of information regarding interfering beams.SELECTED DRAWING: Figure 7

The invention provides a multi-band adaptive regional intelligent light supplement imaging method and device. The device comprises a main support, an angle adjusting support, lamp beads of three bands (810 nm, 910 nm and 1060 nm) and corresponding cameras. According to the equipment, twelve groups of lamp beads are arranged in three rows and four columns, each group comprises lamp beads of three wave bands, and the lamp beads are installed at different inclination angles, so that accurate light supplement for different imaging areas is realized. The system detects the brightness of each area of the image in real time, automatically identifies the overexposure area and the reason thereof, and intelligently adjusts the light supplementing wave band and intensity. When the strong correlation light is detected, a non-interference wave band is automatically switched; and when it is detected that the reflected light is too strong, the light supplementing intensity of the corresponding area is reduced. According to the method, the problems of environment light source interference and non-uniform self light supplement reflection are effectively avoided, the imaging quality at night and in a low-visibility environment is greatly improved, and the perception capability and safety of an automatic driving system are remarkably enhanced.

The invention discloses a method for collecting and processing mountain earthquake data. The method specifically comprises the following steps: S1, surveying a surface structure through an earth surface geological radar technology; s2, carrying out interference wave difference adjustment, recording interference wave survey records in different environments in order to analyze various noise characteristics, carrying out a large amount of statistical analysis on various characteristic values of the noise records, and when a certain environmental factor changes, analyzing the relative change of the characteristic values of the noise records to find out regularity, and proposing a suppression method; then investigating various mixing and secondary interferences after excitation by adopting production arrangement; the invention relates to the technical field of mountain earthquake. According to the mountain earthquake data acquisition and processing method, noise interference factors in the data acquisition process can be well processed, good earthquake data can be provided, good static correction can be performed on the data, good data support is provided for mountain earthquakes, and guarantee is provided for subsequent research work.

The present disclosure provides an interference mitigation cartridge for cardiac vibrational waves. The reduction box comprises an upper end face, side faces, a bottom face and a box body inner cavity defined by the upper end face, the side faces and the bottom face. The impedance wave-absorbing layer on the upper end surface comprises a carbon fiber epoxy layer, a silica gel carbon powder layer and a porous silicone rubber layer of which the impedance values are gradually reduced from large to small, and a through hole is formed in the center of the impedance wave-absorbing layer; the through hole penetrates through the upper lining layer to form an upper inner layer facing the inner cavity of the box body; the damping resonant cavity is formed after a gap between the lower surface of the porous silicon rubber layer and the upper surface of the upper lining layer is sealed at the side edge; the input vibration acquisition plate is embedded into a groove which is sunken downwards from the upper surface of the impedance wave-absorbing layer and is used for receiving and conducting input vibration containing heart vibration waves and environmental interference waves; and the vibration wave sensor is connected with the lower surface of the input vibration acquisition plate through a magnetic connecting piece, is arranged in the inner cavity of the box body and is used for receiving heart vibration waves.

The invention belongs to the technical field of discharge noise processing, and particularly relates to a staff noise reduction method for partial discharge of an ethylene propylene rubber cable. Comprising the following steps of: 1, processing a periodic narrow-band interference signal by adopting an energy ratio method, and removing the narrow-band interference in a partial discharge signal; 2, reprocessing the processed point signal by adopting a generalized S transformation mode; carrying out modular matrix algorithm transformation on the high-frequency partial discharge signal; 3, setting a basic value gamma by adopting a smaller threshold method, and obtaining the number of all narrowband interferences; 4, acquiring effective data of the center frequency; 5, wave crest data below the standard curve are set as interference frequency data, and the wave crest value is an interference wave crest; 6, extracting frequency peak values corresponding to all narrowband interference signals in the atlas according to the interference peak definition; and 7, setting a frequency spectral line corresponding to the peak value as kp. The method is more thorough in noise processing and has good application value.

The invention belongs to the technical field of Internet of Things data processing, and discloses a multi-mode Internet of Things sensor data fusion processing method and system. Comprising the following steps: acquiring multi-modal sensor data in a monitoring environment; performing interference source positioning analysis on the data to generate an interference source distribution map; separating interference waveform characteristics of each modal data based on the distribution map; constructing an interference propagation network by using the features so as to quantify the coupling relationship of interference among different modes; performing noise correlation weakening on original data based on the network to obtain decoupled sensor data; performing dynamic fusion analysis on the decoupling data, and constructing a multi-modal fusion feature vector; and finally, accurately detecting a target event or state based on the feature vector. According to the method, the negative influence of noise correlation on fusion is eliminated, and the accuracy and robustness of target detection and the reliability of the system in a complex environment are improved.

The invention belongs to the field of electronic system resource management, and particularly relates to a real-time adaptive task scheduling method for a multi-channel interference system. The interference system provided by the invention has a plurality of channels, the interference frequency band of each channel can be flexibly controlled, and the system can implement simultaneous interference by the same interference beam for multiple tasks distributed to the same channel, or adopts a digital beam forming (DBF) technology to generate a plurality of interference beams at the same time. Or a simultaneous multi-interference beam is generated by adopting an aperture subarray division mode. The algorithm provided by the invention can enable the system to achieve the purpose of maximizing the execution benefit of the system by effectively controlling the multi-channel interference frequency band, the tasks allocated and executed on each channel and the specific execution mode of each task.

The invention provides a control method for automatically adjusting target optical characteristics, and relates to the technical field of optical characteristic adjustment, and the method comprises the steps: obtaining historical environment data, optical characteristic parameters during detection of optical equipment, and detection signal intensity to form an initial data set, and building an environment detection light beam model; modulating a main detection light beam according to real-time environment data in combination with an environment detection light beam model; acquiring detection echoes of environment noise and the main detection light beam; performing empirical mode decomposition and wavelet transform fusion processing on echo signals; extracting time-frequency domain characteristics of interference waves; interference waves are eliminated by predicting periodic interference characteristics and modulating optical characteristic parameters of an auxiliary detection light beam, and constructive interference with a main light beam is realized by adjusting optical characteristics of the auxiliary detection light beam for non-periodic interference waves, so that an enhanced main detection light beam is formed.

The invention discloses an intelligent electric power system remote monitoring device and a monitoring method thereof, relates to the technical field of electric power monitoring interference prevention, solves the problem that comprehensive and deep feature extraction is difficult to perform on complex waveforms, and provides an intelligent electric power system remote monitoring device and a monitoring method thereof through careful analysis of signal waveform features in a monitored line. A scientific characteristic value sequence recognition system is established; aiming at the standard waveform of each monitoring item, the characteristic value sequence of the standard waveform is accurately locked, and whether the signal waveform is interfered or not can be sensitively identified by virtue of change characteristic analysis and characteristic sequence matching; according to the method, the abnormal waveform points and the interference waveforms are accurately calibrated, a proportion value judgment method is applied, misjudgment caused by parameter numerical value fluctuation is effectively avoided, the interference recognition accuracy is greatly improved, frequency filtering is directly carried out on the waveforms which do not belong to monitoring items, and the filtering efficiency is improved; for the waveforms belonging to the monitoring item, the time of different waveforms is ingeniously adjusted by determining a time difference characteristic sequence.

The invention discloses a distribution network traveling wave head analysis and fault location method and system based on edge calculation. The method comprises the steps that S1, terminal parameters are configured on a power distribution terminal; s2, monitoring a traveling wave signal and a power frequency electrical quantity of the distribution line in real time, and starting wave recording when a traveling wave amplitude exceeds a threshold value; s3, wave recording data are screened through the power frequency electrical quantity change and the traveling wave starting sequence; and S4, carrying out wave head detection on the fault initial traveling wave recording data, carrying out section determination on the fault so as to carry out double-end distance measurement, and then carrying out correction processing on the distance measurement result of the power distribution terminal located in the fault section based on the line section parameters. According to the method, a marginal distribution calculation mode is adopted, and fault identification, wave recording screening and positioning calculation capabilities are integrated on a power distribution terminal side, so that the data communication traffic and the calculation pressure of a master station are greatly reduced, real faults and interference wave recording can be effectively distinguished, and distance measurement errors caused by wave velocity differences in a mixed line in a traditional method are overcome.

[Object]Provided are a radar apparatus that can prevent the leakage of interference waves from a radome, and an on-vehicle sensing system including the radar apparatus.[Solving Means]The radar apparatus of the present disclosure includes a substrate having an antenna structure in which a radiating portion for a radio wave is provided on a first surface, a radome disposed to face the first surface of the substrate, and a radio wave absorbing member disposed between the substrate and the radome, having an opening formed in a portion corresponding to the radiating portion, and including an insulator configured to absorb a radio wave.

The invention relates to the field of speech analysis, and discloses a natural sound interference stripping algorithm and an application thereof in noise monitoring, which are used for efficiently and accurately stripping interference components in a target speech signal in a complex natural sound environment. Comprising the following steps: synchronously acquiring an environmental sound signal by using a spatially distributed microphone array, generating an original mixed voice signal with spatial coherence, performing real-time fractional order differential processing, strengthening resonance characteristics, realizing spatial separation of a voice guided wave mode and an interference radiation mode through real-time phase analysis, and extracting an interference radiation mode component. And reconstructing a time domain interference waveform, and outputting a pure target voice signal according to the original mixed voice signal and the reconstructed interference waveform. The system has the functions of residual interference sound energy recovery, equipment vibration suppression, environment sudden change monitoring, system resetting, bimodal output and the like, the stability, reliability and practicability of the system are effectively improved, and pure voice can be accurately extracted in a complex environment.

The invention relates to a multi-source information fusion airport runway intelligent monitoring method and system, and relates to the technical field of airport runway monitoring, and the method comprises the steps: collecting radar monitoring microwaves of a runway, and carrying out the analysis, so as to determine the position of an interference wave source in the runway; performing microwave signal analysis on the interference wave source position to determine a microwave interference type and interference existence time; matching an adjusting wave band corresponding to the microwave interference weakening type in a preset wave band database; indicating a preset radar monitoring device to perform monitoring band adjustment based on the adjustment band, and marking the position of the interference wave source to generate a to-be-checked path; and performing image acquisition on the to-be-checked path and performing foreign matter image feature analysis to determine dangerous foreign matters and send a cleaning instruction. The method has the effect of improving the accuracy of the runway abnormity monitoring result.

The invention discloses an anti-interference L-band microwave remote sensing radiometer, and the radiometer comprises a radio frequency receiving assembly which comprises a miniaturized array antenna, a single-pole three-throw switch, a band-pass filter, a low-noise amplifier, a frequency mixer, a local oscillation source, an intermediate-frequency filter, an intermediate-frequency amplifier, and a detector; a signal control and acquisition assembly; a calibration component; a data processing and transmitting component; the miniaturized array antenna is used for receiving a radio frequency noise signal in a target direction; the single-pole three-throw switch is used for respectively switching and receiving the radio frequency noise signal in the target direction, a radio frequency noise signal after heat source matching and a radio frequency noise signal after cold source matching; a radio frequency noise signal is processed through a band-pass filter, a low-noise amplifier, a frequency mixer, an intermediate-frequency filter, an intermediate-frequency amplifier and a detector in sequence, and a detection signal is combined with a calibration algorithm to complete noise temperature measurement in a target direction; the data processing and transmission assembly transmits the data to the platform. The radiometer provided by the invention has strong anti-interference capability and can be used for various scenes for retrieving environmental parameters.

The invention relates to the technical field of electronic countermeasures, in particular to an unmanned aerial vehicle group dynamic interception method and system based on distributed interference array collaboration. According to the method, an interference node cluster with autonomous logic association is dynamically deployed in a defense domain, and an elastically reconfigurable distributed interference field domain is formed through a software defined radio architecture; time-varying spectrum features are extracted through an adversarial neural network, and a dynamic threat fingerprint database is constructed; generating an interference vector with frequency band following and power self-adaption based on the dynamic threat fingerprint database, and updating the feature weight of the dynamic threat fingerprint database in real time according to interference efficiency feedback; and according to the situation evolution trend of the dynamic threat fingerprint database, a hierarchical interference wave sequence is generated based on a multi-agent consensus protocol, and a space-time coupled interception chain is formed. Through the method, the whole-process dynamic confrontation capability of the unmanned aerial vehicle group is realized, the efficient interception performance is maintained in a complex electromagnetic environment, and meanwhile, the interference risk on legal communication is reduced.

The invention provides a phase change blasting excitation seismic wave reflection method, a medium, equipment and a product, and relates to the technical field of tunnel engineering, the method comprises the following steps: arranging a detection hole and a plurality of blasting holes in a tunnel face, placing blasting tubes in the blasting holes, placing detectors in the detection hole, and generating seismic waves through phase change blasting; carrying out longitudinal wave and transverse wave separation on seismic wave signals detected by a detector, processing longitudinal waves and transverse waves by adopting a two-dimensional F-K digital filtering method, filtering interference waves, separating effective waves and direct waves, and dividing a data set of the effective waves into a training set and a test set; building a prediction model of the unfavorable geological disaster body in front of the tunnel face based on a support vector machine, and obtaining optimal parameters of the model by using a particle swarm algorithm; and training and testing the model by using the training set and the test set, and applying the tested model to tunnel geological forecast. According to the method, the accuracy of advanced geological forecast of the gas tunnel is improved, and the gas explosion risk is reduced.

The invention discloses a channel environment measured data traveling wave fault distance measurement method, which belongs to the technical field of channel environment traveling wave fault distance measurement, and comprises the following steps of: 1, screening traveling wave fault recording data; step 2, calibrating a traveling wave head; step 3, carrying out power transmission line traveling wave fault distance measurement; and step 4, optimizing the traveling wave distance measurement device. According to the method, fractal dimensions and transient energy are used as feature vectors, a small number of known category historical samples are introduced as prompts, partial supervision clustering is formed, the fault membership degree of weak faults is improved, and blindness of clustering number and initial value selection is avoided. The continuity of a single fault event action and the tightness in time are considered, the time neighborhood constraint is added in the clustering process, and the detection capability of small-fault-angle faults and high-resistance faults far away from a clustering center recognition sample is enhanced. Interference waves are eliminated according to the length and slope characteristics, and reliable calibration of the wave head is achieved.