CN109581518A - One kind is without synchronizing current acquisition transmission and the acquisition of frequency domain measurement SIP data and processing method - Google Patents

Abstract

The present invention is a SIP data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement. The initial phase table file is generated on the basis of the initial phase and amplitude normalization coefficients; that is, the emission frequency table and the initial phase table are generated; the phase value of the excitation current of a certain frequency at any time is used to use its initial emission time and The acquisition time of the frequency voltage data is obtained according to the relative phase calculation method; then the voltage amplitude and phase obtained by the full-phase spectrum analysis are automatically constrained according to the length, that is, the complex resistivity at the frequency point can be obtained. The invention improves the flexibility of the SIP method by getting rid of the dependence of the system on the high-performance synchronous current acquisition and real-time transmission equipment or the high-precision frequency domain observation device, and realizes the smooth development of the SIP method observation in complex environments such as weak GPS signals. .

Description

A SIP data acquisition and processing without synchronization of current acquisition transmission and frequency domain measurement method

technical field

The invention belongs to the field of geophysical electromagnetic detection, and in particular relates to a frequency domain stimulated polarization method (SIP method) data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement.

Background technique

The frequency domain induced polarization method (SIP method) is an important branch of the induced polarization method, and the observation target is the complex resistivity of the measurement area. This method can describe the electrical structure of the underground medium in the survey area in more detail, and is an important detailed investigation method. Compared with other geophysical exploration methods, the SIP method has the advantages of multi-parameter measurement and comprehensive information output.

At present, the existing SIP data collection methods and corresponding observation systems are mainly divided into two types:

(1) Directly collect the amplitude and phase of the voltage signal and the current signal, and then use these frequency domain parameters to calculate the complex resistivity of the measurement area;

(2) Simultaneously collect the time domain data of the voltage signal and the current signal, then perform discrete Fourier transform (DFT), and use the transformed frequency domain parameter results to obtain the complex resistivity of the measurement area.

The first method needs to achieve high-precision frequency domain measurement. The observation system is mainly composed of high-power transmitters, high-precision frequency-domain measurement receivers, electrodes and other devices. The receiver is composed of key modules such as imaginary component channel, real component channel, and correlation detection unit. However, the existing phase measurement methods have high requirements on both the transmitter and the receiver. First of all, it is required that the distortion of the excitation current waveform should be as small as possible, and the zero point should be relatively stable, and the receiver should also have a high zero point stability. However, the electromagnetic signals observed in the field are generally weak, and the phase measurement accuracy cannot be guaranteed. In addition, although the amplitude measurement is easier than the phase measurement, when the ambient noise is large, to complete the high-precision amplitude measurement, it is necessary to increase the power supply current to improve the signal-to-noise ratio. In general, the frequency-domain data acquisition method requires the observation system to have quite high accuracy and stability, which increases the cost of observation and is not conducive to field work.

The system composition of the second observation method includes high-power transmitter, receiver, current detection device, synchronous current transmission device, electrodes and supporting cables and other related peripheral equipment. The system has high requirements on instrument hardware, especially the synchronization, real-time performance of the system and the anti-noise ability of auxiliary devices.

SUMMARY OF THE INVENTION

The purpose of the present invention is to simplify the traditional SIP observation system, improve the flexibility and application range of the SIP method, and propose a new SIP data acquisition and processing algorithm. In order to get rid of the system's dependence on high-performance synchronous current acquisition and real-time transmission equipment or high-precision frequency domain observation devices, the observation cost is reduced; the flexibility of the SIP method is improved, and the SIP can be successfully carried out in complex environments such as weak GPS signals. law observation.

For achieving the above object, the technical scheme of the present invention is:

A method for SIP data acquisition and processing without synchronization of current acquisition and transmission and frequency domain measurement, characterized in that it includes initial phase table generation, relative phase calculation, and absolute phase calculation, wherein the relative phase calculation is a phase shift related to current transmission time , the absolute phase calculation is the initial phase of the current signal;

First, use the absolute phase calculation method to calculate the initial phase and amplitude normalization coefficients of all frequency currents that the transmitter can transmit in advance, and generate the initial phase table file on the basis of the initial phase and amplitude normalization coefficients; Frequency table and initial phase table;

Secondly, the phase value of the excitation current of a certain frequency at any time can be obtained according to the relative phase calculation method by using its initial emission time and the acquisition time of the frequency voltage data;

Finally, the voltage amplitude and phase obtained by the full-phase spectrum analysis are automatically constrained according to the length, that is, the complex resistivity at the frequency point can be obtained;

The length auto-constrained full-phase spectrum analysis is composed of three parts: length auto-constrained full-phase matrix transformation, self-convolution windowing and Fourier transform.

The absolute phase calculation method is:

The full-phase matrix is formed from the original data, and the self-convolution window of N to N points is constrained by the excitation signal frequency f _in and the corresponding sampling rate f _s plus the data length. Lie transform to obtain the absolute phase of the signal;

The data length constraint is to constrain the length N of the full-phase transformation to satisfy the full-cycle truncation. Because the excitation signal of the SIP method is mostly a series of square waves with different frequencies, N should be determined by the excitation signal frequency f _in and the corresponding sampling rate f _s :

Wherein, d ₁ and d ₂ are both integers. d ₁ needs to satisfy that the value in the symbol |||| is an integer, and parameter d ₂ needs to ensure that the window length is greater than the preset threshold σ, which is related to the sampling rate, as shown in Table 1.

Table 1 Window length threshold without sampling rate

make Then _d2 is calculated according to the following formula:

Among them, ceil() means round up.

The described voltage amplitude and phase obtained by automatic constraint full-phase spectrum analysis according to the length, the calculation steps are:

(1) According to the frequency information, the "initial phase table" is looked up to find the current initial phase and amplitude normalization coefficient corresponding to the current frequency;

(2) According to the time information provided by the transmission frequency table and the time when the current voltage data starts to be collected, the time offset Δt between the current data time and the start time of the frequency signal transmission can be obtained. In addition, during the A/D collection process , since the hardware startup interval will cause 128 data points to be lost, the time deviation caused by the missing data points needs to be considered when calculating Δt. This value is related to the current sampling rate f _s . The calculation method of Δt at any time in the data segment is as follows:

where f _in is the current frequency;

n _skip is the starting position of the currently calculated data segment in the voltage data block;

t _ini (f _in ) is the current frequency current start emission time;

t _now (f _in ) is the current voltage signal acquisition time;

(3) Utilize the phase and the amplitude of the full-phase spectrum analysis calculation voltage to automatically constrain the length, and the DFT length N is identical with the full-phase matrix of the current signal of the same frequency;

(4) Calculate the phase of the current signal synchronized with the voltage signal being processed, and the calculation formula is as follows:

(5) Use formula (8) and formula (9) to calculate the complex resistivity phase and amplitude of this frequency point:

in and are the phase values of the current voltage and current, respectively;

in, is the voltage amplitude, is the amplitude normalization coefficient, and I(f _in ) is the current current intensity;

Finally, the calculated results are corrected to obtain the measured complex resistivity information.

The absolute phase solution described is achieved by using length auto-constrained full-phase spectrum analysis.

The transmission frequency table is a "frequency-schedule", which contains the following information: signal type, transmission frequency, current strength and transmission duration.

The initial phase table is an "initial phase-amplitude-frequency table" obtained by using the length automatic constraint full-phase spectrum analysis calculation, and the information contained is: signal frequency, initial phase, amplitude normalization coefficient and length constraint value N .

The phase and amplitude solution method is to look up the "initial phase table" according to the frequency information, find the current initial phase and amplitude normalization coefficient corresponding to the current frequency, and then according to the time information provided by the transmitting frequency table and the current voltage. The time when the data starts to be collected, the time offset Δt between the current data time and the initial transmission time of the frequency signal can be obtained, using the voltage phase at the frequency point and the starting phase, frequency and time offset of the current at this frequency The relationship between the four shifts calculates the phase of the complex resistivity at the frequency point f _in , and the amplitude can be obtained by the normalization method.

Compared with the prior art, the present invention has substantial features and significant effects:

The present invention does not need synchronous current acquisition and transmission and frequency domain measurement device, uses absolute phase calculation method and relative phase calculation method combined with frequency schedule to obtain the current phase, and the amplitude is obtained by normalization. The phase calculation can obtain high-precision phase calculation results without additional correction means, and has the advantages of high precision and simple algorithm compared with traditional DFT and windowed DFT. Its features are:

1. Simplify the traditional SIP observation system, get rid of the dependence of the system on high-performance synchronous current acquisition and real-time transmission equipment or high-precision frequency domain observation device, and reduce the observation cost;

2. The traditional complex resistivity calculation method is improved, and the full-phase spectrum analysis is automatically constrained by the length to improve the phase calculation accuracy

3. The flexibility of the SIP method is improved, and the SIP method observation can be carried out smoothly in complex environments such as weak GPS signals.

Description of drawings

Figure 1 shows the absolute phase calculation method.

Fig. 2 is the data collection and processing flow of the SIP method of the present invention.

FIG. 3 is a method for generating an initial phase table of the present invention.

Fig. 4 is the correction algorithm of the calculation result of complex resistivity.

Figure 5 is a comparison diagram of the calculated and theoretical values of complex resistivity obtained by different algorithms.

Figure 6 is a comparison diagram of the calculated value and theoretical value of SIP complex resistivity under power frequency interference.

Figure 7 is the field measurement result of SIP. The upper graph is the complex resistivity amplitude curve, and the lower graph is the phase curve.

Figure 8 is the SIP observation data processing software interface.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

First of all, the present invention proves that "real part and imaginary part" and "amplitude and phase" of complex resistivity are equivalent through existing theoretical analysis, and the two can be converted into each other. Accordingly, the complex resistivity of a certain frequency can be obtained by using the voltage amplitude and phase of the frequency, and the amplitude and phase of the current signal synchronized with the voltage data of this segment. In addition, the amplitude and phase of the voltage signal can be directly obtained by performing time-frequency transformation on the original sampled data. However, due to the lack of synchronous current data, the spectral information of the current signal cannot be calculated in this way.

In this case, the present invention uses the absolute phase calculation method and the relative phase calculation method in combination with the frequency schedule to obtain the phase of the current, and the amplitude is obtained by normalization. The absolute phase calculation method is implemented using the length auto-constrained full-phase spectrum analysis.

The method of the invention can obtain a high-precision phase calculation result without additional correction means, and has the advantages of high precision and simple algorithm compared with the traditional DFT and the windowed DFT.

The present invention utilizes an absolute phase calculation method, including relative phase calculation and absolute phase calculation, the former refers to the phase shift related to the current transit time, and the latter refers to the initial phase of the current signal. First, calculate the initial phase and amplitude normalization coefficients of all frequency currents that the transmitter can transmit, and then generate the initial phase table file on this basis, that is, generate the transmitting frequency table and the initial phase table; The phase value of the excitation current at any time is obtained by using its initial emission time and the acquisition time of the voltage data at this frequency according to the relative phase calculation method; finally, the voltage amplitude and phase obtained by the full-phase spectrum analysis are automatically constrained according to the length, The complex resistivity at this frequency can be obtained.

For the SIP method transmitter, the initial phase of the output current x(f _in ) at a certain frequency is constant, at least in a short period of time, the value does not change. In this way, the phase of the signal at any time can be calculated and obtained by formula (1).

phase_I _t (f _in )=mod(Δt×f _in )×2π+phase_I _ini (f _in ) (1)

Where: f _in and phase_I _ini (f _in ) are the frequency and initial phase of the current current, respectively, and Δt is the time difference from the moment when the current starts transmitting to the moment when the data is collected.

The above analysis shows that once the amplitude and frequency of the emission current are fixed, its frequency domain parameters at any time can be known with certainty. In addition, the frequency domain information of the voltage signal can be obtained by time-frequency conversion using the original data. In this way, the complex resistivity parameter can be calculated according to formula (2) and formula (3).

phase_ρ(f _in )=phase_U(f _in )-Δphase_I(f _in )-phase_I _ini (f _in )

=phase_U(f _in )-mod(Δt×f _in )×2π-phase_I _ini (f _in ) (2)

Amp_ρ(f _in )=Amp_U(f _in )/Amp_I _ini (f _in ). (3)

Formula (2) shows that the phase of the complex resistivity at the frequency point f _in is determined by the voltage phase phase_U at the frequency point and the initial phase phase_I _ini of the frequency current, the frequency f _in and the transmission time Δt (the transmission start time t The difference between _ini and voltage data acquisition time t _n ) is jointly determined by the four. The amplitude can be obtained by the normalization method.

In this way, in the absence of synchronous current data acquisition and transmission equipment, according to the following parameters: current current frequency f _in , current intensity (amplitude) A, initial phase phase_I _ini and transmission time Δt (relative to the start time of transmission) , the frequency domain information of the current excitation current signal can be determined. This is the theoretical basis for designing the SIP data real-time algorithm in the present invention.

The key problem of the present invention is the calculation of the phase, including the calculation of the relative phase and the calculation of the absolute phase. The former refers to the phase shift relative to the current transit time, while the latter refers to the initial phase of the current signal.

When the signal frequency is stable and known, the complex resistivity phase calculation error may come from the voltage phase error phase_U _err (f _in ), the current initial phase error phase_I _inierr (f _in ), and the time error Δt _err . The first two are determined by the accuracy of the algorithm, and the third is controlled by the accuracy of the time record. Both the current starting phase and the voltage phase are obtained using the absolute phase calculation method.

The most basic and most commonly used phase calculation method is the Fourier transform, which is the discrete Fourier transform (DFT) for discrete signals. Both direct DFT and windowed DFT are affected to some extent by spectral leakage effects. When there is no frequency error or the frequency error is very small, adding window will make the spectral leakage effect more obvious. In addition, the window function can also cause blurring of the main lobe while suppressing the leakage of the side lobes. This effect is especially obvious in the multi-frequency signal processing with dense frequency components.

In order to obtain more accurate spectrum parameters, especially the phase, the present invention adopts the full-phase spectrum analysis with automatic length constraint, and this method has the advantages of small calculation amount and high phase precision. Because the present invention has very high requirements on the phase calculation accuracy, some constraints are added to the full phase transformation.

The length auto-constrained full-phase spectrum analysis consists of three parts: full-phase matrix transformation, auto-length auto-constrained self-convolution windowing and Fourier transform.

As shown in Figure 1, the absolute phase calculation method of the present invention is as follows: the original data constitutes a full-phase matrix, and at the same time, an N-point self-convolution window is obtained from the excitation signal frequency f _in and the corresponding sampling rate f _s plus the data length constraint N, The automatic length-constrained N-point self-convolution window and the full-phase matrix are then subjected to windowed Fourier transform to obtain the absolute phase of the signal.

The data length constraint is to constrain the self-convolution window length N of the full-phase transformation to satisfy the full-cycle truncation. Because the excitation signal of the SIP method is mostly a series of square waves with different frequencies, N should be determined by the excitation signal frequency f _in and the corresponding sampling rate f _s :

Wherein, d ₁ and d ₂ are both integers. d ₁ needs to satisfy that the value in the symbol |||| is an integer, and parameter d ₂ needs to ensure that the window length is greater than the preset threshold σ, which is related to the sampling rate, as shown in Table 1.

Table 2 Window length threshold without sampling rate

make Then _d2 is calculated according to the following formula:

Among them, ceil() means round up.

The specific implementation flow of the SIP method data acquisition and processing method of the present invention is as follows:

As shown in Figure 2, the SIP data acquisition and processing flow chart, first, generate the transmission frequency table and initial phase table, secondly, formulate a "frequency-timetable" (hereinafter referred to as "transmission frequency table"), which contains the following information: Signal type, transmission frequency, current strength and transmission time, etc. The transmit frequency table is then stored in the transmitter and acquisition station. After the observation system starts to work, the transmitter starts to circulate the emission current in turn according to the "transmission frequency table". The receiver is then ready to start collecting voltage data. This is less limited than the current commonly used SIP data collection methods. To ensure that voltage signals of all frequencies can be collected, the total collection time cannot be less than the total time of one cycle. Then calculate the complex resistivity amplitude and phase, the calculation steps are:

(1) According to the frequency information, the "initial phase table" is looked up to find the current initial phase and amplitude normalization coefficient corresponding to the current frequency;

(2) According to the time information provided by the transmission frequency table and the time when the current voltage data starts to be collected, the time offset Δt between the current data time and the start time of the frequency signal transmission can be obtained. In addition, during the A/D collection process , since the hardware startup interval will cause 128 data points to be lost, the time deviation caused by the missing data points needs to be considered when calculating Δt. This value is related to the current sampling rate f _s . The calculation method of Δt at any time in the data segment is as follows:

where f _in is the current frequency;

n _skip is the starting position of the currently calculated data segment in the voltage data block;

t _ini (f _in ) is the current frequency current start emission time;

t _now (f _in ) is the current voltage signal acquisition time;

(3) The phase and amplitude of the voltage are calculated by using the length automatic constraint full-phase spectrum analysis, and the DFT length N is the same as the full-phase transform self-convolution window length of the current signal of the same frequency;

(4) Calculate the phase of the current signal synchronized with the voltage signal being processed, and the calculation formula is as follows:

(5) Use formula (8) and formula (9) to calculate the complex resistivity phase and amplitude of this frequency point:

in and are the phase values of the current voltage and current, respectively.

in, is the voltage amplitude, is the amplitude normalization factor and I(f _in ) is the current current intensity.

Finally, the calculated results are corrected to obtain the measured complex resistivity information.

As shown in FIG. 3 , the method for generating an initial phase table of the present invention is shown. Before the SIP method is formally observed, the signals of all frequencies generated by the SIP transmitter are collected, and then their initial phases and normalized amplitude coefficients are calculated by using the length automatic constrained full-phase spectrum analysis, and on this basis, the "initial phase" is generated. - Amplitude-frequency table" (hereinafter referred to as "initial phase table"), the information contained in this table is: signal frequency, initial phase, amplitude normalization coefficient and length constraint value N. The initial phase table file format is shown in Table 2. Among them, the first column is the excitation current frequency, and the second and third columns are the initial phase and amplitude normalization coefficients of the directly sampled data. The fourth and fifth columns are the initial phase and amplitude normalization coefficients of the data processed with the harmonic filter. Because the field observation environment is complex, when the power frequency interference is strong, it is necessary to perform power frequency filtering first. The filter will have a certain impact on the amplitude and phase of the original sampled data, especially the phase. Therefore, the transmission current filter is added to the initial frequency table. spectrum information for real-time data processing in the field.

Table 3 "Initial Phase Table" file format

Initial phase table generation process. The data processing process in the two dashed boxes is exactly the same. Table 3 is an example of a transmit frequency table. FD represents that the signal waveform is a square wave. Each frequency signal is continuously cyclically transmitted. The transmission end time refers to the difference between the current frequency signal transmission end time and the first frequency signal transmission start time. For example, assuming that the 128Hz signal in Table 3 starts to be sent at 00:00:00, the frequency signal ends at 00:00:50, and the 64Hz signal starts to transmit until 00:01:40, and the following signals are deduced in turn.

Table 4 Transmit frequency table

Because the measurement results of the electromagnetic method in the frequency domain include the response of the system itself, it is necessary to correct the calculation results through the calibration data, so that the real complex resistivity information of the measurement area can be finally obtained.

As shown in Figure 4, the complex resistivity calculation result correction method. Since the frequency values used for each observation are not necessarily the same, and the number of frequency points to be calibrated is limited, the correction coefficient needs to be calculated by interpolation method first. According to the signal frequency f _in , check the calibration data table to find the adjacent points of f _in , then use the interpolation method to calculate the spectral correction coefficient at f _in , and finally use the calculated correction coefficient to correct the original calculation result. The interpolation algorithm adopted in the present invention is parabolic interpolation, so first look up the table to find three frequency points closest to f _in : f _k-1 , f _k and f _k+1 . Then calculate the interpolation result according to the formula:

where r(f) represents the amplitude or phase scaling result at frequency f.

The complex resistivity correction formula is as follows:

φ(f _in )=φ(f _in )-φ _c (f _in )

ρ(f _in )=ρ(f _in )/ρ _c (f _in ) (11)

Among them, φ _c (fin ) and ρ _c ( _fin ) are the amplitude and phase of the self-response of the observation system at the frequency f _{in ,} respectively, and are obtained by calculation according to formula (10).

For the flow of the above data collection and processing method, see Figure 1.

The calculated and theoretical values of complex resistivity obtained by different algorithms can be compared through simulation experiments.

As shown in Figure 5, the solid line in the figure represents the theoretical complex resistivity curve; the dotted line represents the results obtained by using the synchronous voltage and current data, and the discrete points represent the calculation results of the new method; "*", "Δ" and "□" respectively It represents the calculation results of the three methods of length auto-constrained full-phase spectrum analysis, windowed DFT and direct DFT. The upper graph is the complex resistivity amplitude and the lower graph is the phase.

In order to verify the reliability of the algorithm, on the basis of the signal I, the simulated power frequency interference is added as the excitation current. Power frequency interference consists of a group of sine waves of 50Hz and its odd multiples. Then repeat the above simulation and data processing procedures.

As shown in Figure 6, the complex resistivity calculation results are shown in Figure 6, and the algorithms represented by different symbols and line types are consistent with those in Figure 5. The data processing method adopted is similar to that without harmonic interference, except that power frequency filtering is added in the early stage.

The calculation accuracy of the complex resistivity of the above several methods is discussed by variance analysis. The results are summarized in Table 4. The simulation test proves that in the case of no power frequency interference, the calculation accuracy of the traditional SIP data processing method requiring synchronous current is higher than that of the new algorithm proposed by the present invention, but in the case of power frequency interference, the new algorithm of the present invention is outperforms traditional algorithms. For the new algorithm itself, the amplitude accuracy obtained by direct DFT, windowed DFT and length auto-constrained full-phase spectrum analysis is basically the same, but the phase accuracy obtained by using the length auto-constrained full-phase spectrum analysis of the present invention is significantly higher than the previous one. both.

Table 5 Mean square error of different SIP data algorithms

As shown in Figure 7, it is the field test result of the SIP method of the present invention. Table 3 is used as the transmission frequency table, and the data acquisition time is about half an hour, and three channels of voltage data are obtained in total.

The complex resistivity amplitude and phase curves measured by the SIP method in the field test are relatively smooth, and the three channels are basically the same. The high-frequency phase of channel 1 is slightly lower than the measurement results of the other two channels.

The results show that the SIP real-time data acquisition and processing method proposed by the present invention can successfully complete the SIP observation without synchronous current acquisition and transmission equipment and frequency domain measurement devices. In addition, the conventional SIP method for data collection requires that voltage data and current data must be collected strictly synchronously. In comparison, the SIP data collection method of the present invention that only collects voltage data is more flexible and convenient.

As shown in Figure 8, the SIP observation data processing software interface, the figure shows the comparison of the SIP observation results obtained by the length automatic constraint full-phase spectrum analysis and the windowed Fourier transform method.

In Fig. 8, (a) and (b) are the time-domain waveform and frequency-domain waveform of the original voltage sampling data. (c) and (d) are the amplitude and phase calculations of the complex resistivity. (e) is the parameter setting and display part, where Array is the device type, "4" represents the symmetrical quadrupole device; AB is the supply electrode pitch; MN is the measuring electrode pitch. These parameters were entered manually before the measurement started, depending on how the device was set up. K is the device coefficient, which is automatically calculated by the program based on the input parameters. f _in is the current signal frequency, which is determined according to the data acquisition time and the transmission frequency table, and the sampling rate f _s is determined according to f _in . The solid line, the dotted line and the dashed line represent channel 1/2/3 respectively, "*" represents the calculation result of the length automatic constraint full-phase spectrum analysis of the present invention, and "Δ" represents the calculation result of the windowed Fourier transform method.

Claims (6)

1. A method for collecting and processing SIP data without synchronizing current acquisition and transmission and frequency domain measurement, it is characterized in that: comprise initial phase table generation, relative phase calculation and absolute phase calculation, and described relative phase calculation is related to current transmission time Phase shift, the absolute phase calculation is the initial phase of the current signal; the SIP data acquisition and processing methods are: First, use the absolute phase calculation method to calculate the initial phase and amplitude normalization coefficients of all frequency currents that the transmitter can transmit in advance, and generate the initial phase table file on the basis of the initial phase and amplitude normalization coefficients; Frequency table and initial phase table; Secondly, the phase value of the excitation current of a certain frequency at any time can be obtained according to the relative phase calculation method by using its initial emission time and the acquisition time of the frequency voltage data; Finally, the voltage amplitude and phase obtained by the full-phase spectrum analysis are automatically constrained according to the length, that is, the complex resistivity at the frequency point can be obtained; The length auto-constrained full-phase spectrum analysis consists of three parts: full-phase matrix transformation, auto-length auto-constrained self-convolution windowing and Fourier transform. 2. a kind of SIP data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement according to claim 1, is characterized in that: described absolute phase calculation method is: The original data constitutes a full-phase matrix, and at the same time, the N-point self-convolution window is obtained by the excitation signal frequency f _in and the corresponding sampling rate f _s plus the data length constraint N, and the N-point self-convolution window and the full-phase matrix are then added to the window Fourier Leaf transformation to obtain the absolute phase of the signal; The data length constraint is to constrain the self-convolution window length N of the full-phase transformation to make it meet the full cycle truncation; because the excitation signal of the SIP method is mostly a series of square waves with different frequencies, N should be determined by the excitation signal frequency. f _in and the corresponding sampling rate f _s to decide: Among them, d ₁ and d ₂ are both integers, d ₁ must satisfy the value of the integer in the symbol, and the parameter d ₂ must ensure that the window length is greater than the preset threshold σ, which is related to the sampling rate, as shown in Table 1; Table 1 Window length threshold without sampling rate make Then _d2 is calculated according to the following formula: Among them, ceil() means round up. 3. a kind of SIP data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement according to claim 1, is characterized in that: the described voltage amplitude and the phase obtained according to the length automatic constraint full-phase spectrum analysis method, The calculation steps are: (1) Look up the "initial phase table" according to the frequency information, and find the current initial phase and amplitude normalization coefficient corresponding to the current frequency; (2) According to the time information provided by the transmission frequency table and the time when the current voltage data starts to be collected, the time offset Δt between the current data time and the start time of the frequency signal can be obtained. In addition, during the A/D collection process , since the hardware startup interval will cause 128 data points to be lost, the time deviation caused by the missing data points needs to be considered when calculating Δt. This value is related to the current sampling rate f _s . The calculation method of Δt at any time in the data segment is as follows: where f _in is the current frequency; n _skip is the starting position of the currently calculated data segment in the voltage data block; t _ini (f _in ) is the current frequency current start emission time; t _now (f _in ) is the current voltage signal acquisition time; (3) The phase and amplitude of the voltage are calculated by using the length automatic constraint full-phase spectrum analysis, and the DFT length N is the same as the full-phase transform self-convolution window length of the current signal of the same frequency; (4) Calculate the phase of the current signal synchronized with the voltage signal being processed, and the calculation formula is as follows: (5) Use formula (8) and formula (9) to calculate the complex resistivity phase and amplitude of this frequency point: in and are the phase values of the current voltage and current, respectively; in, is the voltage amplitude, is the amplitude normalization coefficient, and I(f _in ) is the current current intensity; Finally, the calculated results are corrected to obtain the measured complex resistivity information. 4. a kind of SIP data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement according to claim 3, is characterized in that: described transmission frequency table is a " frequency-timetable ", which contains the following information : Signal type, transmission frequency, current intensity and transmission duration, etc. 5 . The method for collecting and processing SIP data without synchronizing current acquisition and transmission and frequency domain measurement according to claim 3 , wherein the absolute phase solution is realized by using length automatic constraint full-phase spectrum analysis. 6 . 6. a kind of SIP data acquisition and processing method without synchronous current acquisition and transmission and frequency domain measurement according to claim 3, is characterized in that: described initial phase table is a kind of using length automatic constraint full-phase spectrum analysis calculation to obtain The "Initial Phase-Amplitude-Frequency Table" contains the following information: signal frequency, initial phase, amplitude normalization coefficient and length constraint value N.