CN115128592A - Debris flow surface flow velocity monitoring method and system - Google Patents
Debris flow surface flow velocity monitoring method and system Download PDFInfo
- Publication number
- CN115128592A CN115128592A CN202210648037.XA CN202210648037A CN115128592A CN 115128592 A CN115128592 A CN 115128592A CN 202210648037 A CN202210648037 A CN 202210648037A CN 115128592 A CN115128592 A CN 115128592A
- Authority
- CN
- China
- Prior art keywords
- signal
- frequency
- debris flow
- target
- mixing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
- G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
- G01S13/584—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets adapted for simultaneous range and velocity measurements
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
The utility model relates to a debris flow surface velocity monitoring method and system, which belongs to the geological monitoring field and can improve the stability of monitoring the debris flow surface velocity. The method comprises the following steps: transmitting radar measurement signals to the monitored debris flow area; receiving echo signals reflected by the debris flow area; performing two-way frequency mixing processing on the echo signals to obtain intermediate frequency beat signals; acquiring target Doppler frequency corresponding to the intermediate frequency beat signal; and obtaining the surface flow velocity of the debris flow in the debris flow area based on the target Doppler frequency.
Description
Technical Field
The disclosure relates to the field of geological monitoring, in particular to a debris flow surface flow velocity monitoring method and a debris flow surface flow velocity monitoring system.
Background
One of effective means for preventing and treating the debris flow disasters is building and governing engineering, but serious disaster accidents can also be caused in front of the over-frequency debris flow disasters due to unpredictability of sudden debris flow disasters. With the rapid development of the geologic hazard monitoring technology, how to make the geologic hazard monitoring system more accurate and the user monitoring better is always the direction of the industry efforts.
At present, a debris flow monitoring technology adopts a contact type flow velocity meter, the contact type flow velocity meter is installed inside fluid through a propeller type flow velocity meter, and the flow velocity is measured by utilizing the mechanical principle. Another camera-based video image processing method can also extract the flow velocity of the fluid, which is very affected by weather conditions, so that the measurement result has large error and high cost.
Disclosure of Invention
The purpose of the present disclosure is to provide a method and a system for monitoring the surface flow velocity of a debris flow, which can improve the stability of monitoring the surface flow velocity of the debris flow.
According to a first embodiment of the present disclosure, there is provided a method for monitoring a surface flow velocity of a debris flow, including:
transmitting radar measurement signals to a monitored debris flow area;
receiving echo signals reflected by the debris flow area;
performing two-way frequency mixing processing on the echo signal to obtain an intermediate frequency beat signal;
acquiring target Doppler frequency corresponding to the intermediate frequency beat signal;
and obtaining the surface flow velocity of the debris flow in the debris flow area based on the target Doppler frequency.
In some embodiments, performing two-way mixing processing on the echo signal to obtain an intermediate frequency beat signal includes:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain the intermediate frequency beat signal.
In some embodiments, the intermediate frequency beat signal is:
wherein f is c Is the starting frequency, B is the radar signal bandwidth, T is the time width, T d And t is the time in the sweep frequency period, and j is an imaginary number symbol.
In some embodiments, the acquiring a target doppler frequency corresponding to the intermediate frequency beat signal includes:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming a target matrix with Q rows and N columns by the Q one-dimensional distance direction compression processing data, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring a peak position in the target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
In some embodiments, said deriving a surface flow velocity of the debris flow in the debris flow region based on the target doppler frequency comprises:
processing the Doppler frequency by using a velocity measurement formula to obtain the surface velocity of the debris flow in the debris flow area, wherein the velocity measurement formula is as follows:
wherein f is d The target Doppler frequency value is shown, v is the surface flow velocity of the debris flow, and λ is the wavelength.
In some embodiments, the radar measurement signal is a sawtooth wave in which at least two different frequency sweep periods are operated alternately.
According to a second embodiment of the present disclosure, there is provided a debris flow surface velocity monitoring system, including:
the signal transmitting module is used for transmitting radar measuring signals to the monitored debris flow area;
the signal receiving module is used for receiving echo signals reflected by the debris flow area;
and the signal processing module is used for carrying out two-path frequency mixing processing on the echo signal to obtain an intermediate frequency beat signal, acquiring a target Doppler frequency corresponding to the intermediate frequency beat signal, and acquiring the surface flow velocity of the debris flow in the debris flow area based on the target Doppler frequency.
In some embodiments, the signal processing module is further configured to:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain the intermediate frequency beat signal.
In some embodiments, the signal processing module is further configured to:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming the Q one-dimensional distance direction compressed data into a target matrix with Q rows and N columns, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring a peak position in the target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
In some embodiments, the intermediate frequency beat signal is:
wherein, f c Is the starting frequency, B is the radar signal bandwidth, T is the time width, T d For echo time delay, t is the time within the sweep period, and j is the imaginary symbol.
In some embodiments, the signal processing module is further configured to:
processing the Doppler frequency by using a speed measurement formula to obtain the surface flow velocity of the debris flow in the debris flow area, wherein the speed measurement formula is as follows:
wherein f is d The target Doppler frequency value is shown, v is the surface flow velocity of the debris flow, and λ is the wavelength.
In some embodiments, the radar measurement signal is a sawtooth wave in which at least two different frequency sweep periods are operated alternately.
By adopting the technical scheme, the debris flow surface flow velocity monitoring method in a radar non-contact manner can avoid the defect that monitoring equipment in a contact debris flow surface flow velocity monitoring method in the related art is easy to damage, improve the stability and safety of debris flow surface flow velocity monitoring, and is not easy to be influenced by weather conditions due to good penetrability and high anti-interference capability of transmitted electromagnetic waves.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
fig. 1 shows a flow chart of a debris flow surface flow velocity monitoring method according to an embodiment of the present disclosure.
FIG. 2 illustrates a time domain plot of a sawtooth wave according to one embodiment of the present disclosure.
FIG. 3 shows a schematic block diagram of a debris flow surface velocity monitoring system according to an embodiment of the present disclosure.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
Fig. 1 shows a flow chart of a debris flow surface flow velocity monitoring method according to an embodiment of the present disclosure. As shown in fig. 1, the method includes:
in step S11, a radar measurement signal is transmitted to the monitored debris flow area.
In the embodiment of the present disclosure, a radar measurement signal may be transmitted to the monitored debris flow area through a signal transmitting module, and optionally, the signal transmitting module may be a signal transmitting antenna of a millimeter wave radar.
In step S12, an echo signal reflected by the debris flow region is received.
In the embodiment of the present disclosure, a millimeter wave radar may be used, and after the millimeter wave radar is installed, the operating parameters of the millimeter wave radar may be set.
Specifically, a millimeter wave radar non-contact type, a sending and receiving mode can be set, the sending and receiving mode refers to that a sending antenna is used for sending frequency modulation continuous wave signals to a tested debris flow area, and a receiving antenna is used for receiving echo signals reflected by the tested area.
In some embodiments, in order to fully exert the advantages of all weather, all-day time and no influence of factors such as climate and environment of the system, and adapt to the scene of debris flow, the frequency of a transmitted signal of the radar can be set to be 77 GHz-79 GHz, the frequency sweep period is 200 mus, and the bandwidth is 500 MHz.
In the embodiment of the disclosure, the waveform of the radar measurement signal is a sawtooth wave. The time domain diagram of the sawtooth wave is shown in fig. 2, the solid line represents the transmission signal of the millimeter wave radar, and the dotted line represents the received echo signal. Because the sweep frequency time width in each period is far larger than the echo time delay corresponding to the maximum action distance of the millimeter wave radar, the distance of the target can be effectively obtained by utilizing the relatively stable frequency difference between the echo and the transmitted radar measurement signal. It can be seen from fig. 2 that the echo signal has the same shape as the time-frequency diagram of the transmitted measurement signal, except that the echo signal generates a t with respect to the transmitted radar measurement signal d The delay of (2). Since the chirp rate μ is equal to B/T, the chirp rate μ is also fixed when the bandwidth B and the time width T are constant. Thus, the echo delay t can be determined by the frequency difference between the echo and the transmitted radar measurement signal d 。
In the case where the amplitude of the transmission signal and the amplitude attenuation of the echo signal are not considered, and the initial phase of the transmission signal is 0. The emission signal of the radar in a single sweep frequency period [ -T/2, T/2] is as follows:
wherein f is c The frequency is the starting frequency, B is the radar signal bandwidth, T is the time width, and T is the time in the sweep frequency period.
From the above analysis, the received echo signals are:
where td is the echo time delay.
In step S13, two-way mixing processing is performed on the echo signal to obtain an intermediate frequency beat signal.
In some embodiments, performing two-way mixing processing on the echo signal to obtain an intermediate frequency beat signal includes:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain an intermediate frequency beat signal.
In the embodiment of the present disclosure, a Voltage Controlled Oscillator (VCO) may output a frequency modulation signal, and the frequency modulation signal is divided into two paths by a power divider, where one path of the signal is used as a local oscillator signal required by a mixer, the signal is divided into two paths of signals, one path of the signal is subjected to 90 ° phase shift and then enters the mixer of a Q channel as a first reference signal, and the other path of the signal directly enters the mixer of an I channel as a second reference signal.
And the other path of signal separated by the power divider is transmitted out through the transmitting antenna, forms an echo signal when contacting a measured debris flow area, and receives the reflected echo signal through the receiving antenna.
In addition, in the embodiment of the present disclosure, after receiving the echo signal, the echo signal may be filtered and amplified by the filter and the low noise amplifier to obtain an intermediate signal.
Then, dividing the intermediate signal into two paths, wherein one path is sent to a mixer of the I channel and is mixed with a reference signal therein to obtain an in-phase intermediate frequency signal; and the other path of the signal is sent to a mixer of a Q channel and is mixed with a local oscillator signal subjected to 90-degree phase shift to obtain an orthogonal intermediate frequency signal. In this case, the two mixed signals obtained by mixing the intermediate signal may be referred to as a first mixed signal and a second mixed signal, respectively.
Finally, the first mixing signal and the second mixing signal can be mixed to obtain an intermediate frequency beat signal.
In some embodiments, the intermediate frequency beat signal is:
wherein f is c Is the starting frequency, B is the radar signal bandwidth, T is the time width, T d For echo time delay, t is the time within the sweep period, and j is the imaginary symbol.
It should be noted that the first reference signal and the second reference signal may also be replaced, that is, the signal that enters the mixer of the Q channel after being phase-shifted by 90 ° is used as the second reference signal, and the signal that directly enters the mixer of the I channel is used as the first reference signal.
In step S14, a target doppler frequency corresponding to the intermediate frequency beat signal is acquired.
In some embodiments, acquiring a target doppler frequency corresponding to the intermediate frequency beat signal includes:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming Q one-dimensional distance direction compressed data into a target matrix with Q rows and N columns, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring a peak position in a target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
In the embodiment of the present disclosure, a two-dimensional FFT (fourier transform) operation may be performed on the intermediate frequency beat signal, that is, an FFT operation is performed on the distance dimension of the signal first, and an FFT operation is performed on the doppler dimension. That is, firstly, performing one-dimensional range compression on the intermediate frequency beat signal, after Q pieces of one-dimensional range compression data are obtained, forming Q rows and N columns of matrixes by the Q pieces of one-dimensional range compression data, wherein N is a range acquisition point number, and Q is a total acquisition cycle number, then performing row-to-column FFT on the obtained matrix signal to obtain a target frequency domain, finding a peak (peak) position in the target frequency domain, and solving a doppler frequency corresponding to the peak position as a target doppler frequency corresponding to the intermediate frequency beat signal.
In some embodiments, considering that the intermediate frequency beat signal is an analog signal, for convenience of subsequent processing, after obtaining the intermediate frequency beat signal, the intermediate frequency beat signal may be subjected to a/D sampling to obtain a corresponding digital signal, and then the digital signal is subjected to subsequent two-dimensional fourier transform.
In step S15, a surface flow velocity of the debris flow in the debris flow area is obtained based on the target doppler frequency.
In the embodiment of the disclosure, after the target doppler frequency is obtained, the target doppler frequency can be brought into a velocity measurement formula to obtain the surface velocity of the debris flow in the debris flow area.
In some embodiments, deriving a surface flow velocity of the debris flow in the debris flow region based on the target doppler frequency comprises:
processing the Doppler frequency by using a velocity measurement formula to obtain the surface velocity of the debris flow in the debris flow area, wherein the velocity measurement formula is as follows:
wherein f is d And v is the surface flow velocity of the debris flow, and lambda is the wavelength.
The above formula is derived below.
The echo delay t is known from the propagation principle of electromagnetic waves d Not only with the distance R of the target (debris flow) from the radar, but also with the speed of movement of the target relative to the radar, i.e. t d 2(R + vt)/c, c is the speed of light, v when the target is far away>0. Substitute it into formula
And replacing the base band with a chirp rate mu-B/T to obtain:
neglecting c due to too large a light speed c -2 Second order term and use phase
Replacing the following steps:
the intermediate frequency beat signal of the echo of the moving object is a signal with a center frequency of
Slope of frequency modulation of
Is used to generate the chirp signal. And the frequency modulation bandwidth of the intermediate frequency beat signal
Due to v<<c, it may be ignored. Thus, the equation
The following can be obtained:
according to the formula
It can be seen that the center frequency of the intermediate frequency beat signal is defined by a frequency related to the distance
And a velocity dependent Doppler frequency
The composition is as follows:
so that the speed and distance of the target are respectively:
substituting Doppler frequency into velocity measurement formula
In which f is d Is the doppler frequency value of the target, v is the estimated moving target (debris flow surface) flow velocity, and λ is the wavelength.
By adopting the technical scheme, the debris flow surface flow velocity monitoring method in a radar non-contact manner can avoid the defect that monitoring equipment in a contact debris flow surface flow velocity monitoring method in the related art is easy to damage, improve the stability and safety of debris flow surface flow velocity monitoring, and is not easy to be influenced by weather conditions due to good penetrability and high anti-interference capability of transmitted electromagnetic waves.
In some embodiments, the radar measurement signal is a sawtooth wave in which at least two different frequency sweep periods are operated alternately.
In the embodiment of the disclosure, according to the formula
It can be seen that the center frequency of the intermediate frequency beat signal is defined by a distance-dependent frequency f r And a velocity dependent Doppler frequency f d To determine the central frequency f of the intermediate-frequency beat signal b Windowing and Fourier transformation are carried out on the signal, and if rectangular windowing is carried out on the signal, the method comprises the following steps: the signals outside the single sweep period are regarded as 0, and the following results are obtained:
as can be seen from the above equation, the amplitude characteristic of the intermediate frequency beat signal after fourier transform follows a sinc function with a center frequency offset, and the offset frequency is the center frequency of the intermediate frequency beat signal. When the probe object is stationary or relatively low in velocity, the doppler frequency can be ignored, and the center frequency is considered to be entirely generated by the distance between the receiving antenna and the object, i.e.: f. of r ≈f b Thus, the distance between the receiving antenna and the target is:
as known from the fourier transform property, the frequency resolution Δ f is 1/T, and therefore, the distance resolution is:
as can be seen from the above equation, the size of the theoretical range resolution is related to the bandwidth B, and increasing the theoretical range resolution can be achieved by increasing the bandwidth. When the object is in motion and the motion speed cannot be ignored, if the object is in motionBy f r ＝f b Solving the distance of the target from the radar by formula
It is understood that when the target speed v > 0, f is obtained r Larger than the true value and thus far from the true distance, whereas when the target velocity v < 0, the distance is closer than the true distance, which is a distance-velocity coupling problem.
When solving the target speed-distance coupling problem, the Doppler frequency f of the target is obtained by using the weak change of the amplitude value of the intermediate frequency beat signal of a plurality of sawtooth wave frequency sweeps at the central frequency d . This corresponds to sampling the frequency-amplitude function of a fourier transform over a number of sweep periods at the center frequency with a time interval T. Thus, the sampling frequency f of the velocity dimension FFT s 2-1/T, the frequency resolution of the velocity dimension FFT is Δ f s ，2＝1/NT。
Radar speed resolution is the ability to separate out targets with very small differences in speed, and therefore, Δ f d ＝Δf s 2-1/NT, i.e. the velocity resolution is:
therefore, the speed resolution mainly depends on the time width of a single sweep and the number of the processed sweeps, that is, the speed resolution can be improved by increasing the time width T of the single sweep or increasing the number N of the sweeps in a frame.
According to the Nyquist sampling theorem, the maximum unambiguous frequency of the target which can be measured by the Doppler dimension FFT conversion is +/-f s 2/2, therefore, the maximum unambiguous speed of the target measured using this method is:
when the moving speed of the target is greater than the maximum non-fuzzy speed, the undersampling principle is adoptedIt can be known that the Doppler frequency f is measured d ＝f d ′-2nf d，max Where fd' is the true Doppler frequency of the target. From this, the generated speed and distance errors are:
v′＝2nv max
therefore, when the moving speed of the target is greater than the maximum non-fuzzy speed, the distance and the speed of the measured target still have the coupling problem, and the errors of the speed and the distance are too large to be ignored. Therefore, there is a need to improve the maximum unambiguous speed parameter of a radar system.
From the above formula, when the target velocity is too high, the measured Doppler frequency f d ＝f d ′-2nf d，max Therefore, more than two sawtooth waves with different sweep frequency periods working alternately are adopted, and the principle of detecting the blind speed by using the staggered repetition frequency of the sawtooth waves and the pulse radar is applied, so that the maximum non-fuzzy speed is greatly improved.
For example, suppose that two sawtooth waves with respective sweep periods T1 and T2 are used for modulation, and the maximum unambiguous doppler frequencies corresponding to different sweep periods are:
maximum unambiguous Doppler frequency f adopting two alternative sweep frequency modes d Is 2f d1 、2f d2 The least common multiple of. When the wavelength λ is 4mm, the periods and maximum Doppler frequencies of the frequency sweeps 1 and 2 are respectively
The corresponding maximum non-fuzzy speeds are respectively: v1, max ± 33.33m/s, v2, max ± 20m/s, maximum unambiguous doppler frequency when using the two alternating modes
Maximum unambiguous speedvmax ═ 200 m/s. Therefore, the sawtooth waves with at least two alternative sweep frequency periods can effectively improve the maximum non-fuzzy speed, reduce the measurement error caused by the fact that the moving speed of the debris flow exceeds the maximum speed detectable by a radar, and enable the measurement result to be more accurate.
In some embodiments, the surface flow velocity of the debris flow in the debris flow area may be continuously detected when the debris flow occurs, so that after a continuous detection result of the surface flow velocity of the debris flow in the debris flow area is obtained, the surface flow velocity of the debris flow in the debris flow area may be displayed on a monitoring screen through an image display technology, so that a user may more clearly know information of the surface flow velocity of the debris flow in the debris flow area at different times.
FIG. 3 shows a schematic block diagram of a debris flow surface velocity monitoring system according to an embodiment of the present disclosure. As shown in fig. 3, the system 300 includes a signal transmitting module 310, a signal receiving module 320, and a signal processing module 330. Wherein:
the signal transmitting module 310 is used for transmitting radar measuring signals to the monitored debris flow area;
the signal receiving module 320 is configured to receive an echo signal reflected by the debris flow area;
the signal processing module 330 is configured to perform two-way frequency mixing processing on the echo signal to obtain an intermediate frequency beat signal, obtain a target doppler frequency corresponding to the intermediate frequency beat signal, and obtain a surface flow velocity of the debris flow in the debris flow area based on the target doppler frequency.
In some embodiments, the signal processing module 330 is further configured to:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain the intermediate frequency beat signal.
In some embodiments, the signal processing module 330 is further configured to:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming a target matrix with Q rows and N columns by the Q one-dimensional distance direction compression processing data, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring a peak position in the target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
In some embodiments, the intermediate frequency beat signal is:
wherein f is c Is the starting frequency, B is the radar signal bandwidth, T is the time width, T d For echo time delay, t is the time within the sweep period, and j is the imaginary symbol.
In some embodiments, the signal processing module 330 is further configured to:
processing the Doppler frequency by using a velocity measurement formula to obtain the surface velocity of the debris flow in the debris flow area, wherein the velocity measurement formula is as follows:
wherein, f d The target Doppler frequency value is shown, v is the surface flow velocity of the debris flow, and λ is the wavelength.
In some embodiments, the radar measurement signal is a sawtooth wave in which at least two different frequency sweep periods are operated alternately.
In some embodiments, the signal transmitting module 310 may be a signal transmitting antenna of a millimeter-wave radar, the signal receiving module 320 may be a signal receiving antenna of the millimeter-wave radar, and the signal processing module 330 may include hardware modules such as a filter, a low noise amplifier, a power divider, a mixer, and an a/D converter of the millimeter-wave radar, and may also include various software algorithm modules for calculation.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. To avoid unnecessary repetition, the disclosure does not separately describe various possible combinations.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.
Claims (10)
1. A debris flow surface flow velocity monitoring method is characterized by comprising the following steps:
transmitting radar measurement signals to the monitored debris flow area;
receiving echo signals reflected by the debris flow area;
performing two-way frequency mixing processing on the echo signal to obtain an intermediate frequency beat signal;
acquiring a target Doppler frequency corresponding to the intermediate frequency beat signal;
and obtaining the surface flow velocity of the debris flow in the debris flow area based on the target Doppler frequency.
2. The method according to claim 1, wherein the performing two-way mixing processing on the echo signal to obtain an intermediate frequency beat signal includes:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain the intermediate frequency beat signal.
3. The method of claim 2, wherein the intermediate frequency beat signal is:
wherein f is c Is the starting frequency, B is the radar signal bandwidth, T is the time width, T d For echo time delay, t is the time within the sweep period, and j is the imaginary symbol.
4. The method according to claim 1, wherein the obtaining a target doppler frequency corresponding to the intermediate frequency beat signal comprises:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming the Q one-dimensional distance direction compressed data into a target matrix with Q rows and N columns, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring a peak position in the target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
5. The method of claim 1, wherein said deriving a surface flow velocity of debris flow in the debris flow zone based on the target doppler frequency comprises:
processing the Doppler frequency by using a velocity measurement formula to obtain the surface velocity of the debris flow in the debris flow area, wherein the velocity measurement formula is as follows:
wherein, f d The target Doppler frequency value is shown, v is the surface flow velocity of the debris flow, and λ is the wavelength.
6. Method according to claim 1, characterized in that the radar measurement signal is a sawtooth wave with at least two different frequency sweep periods working alternately.
7. A debris flow surface velocity of flow monitoring system, characterized by includes:
the signal transmitting module is used for transmitting radar measuring signals to the monitored debris flow area;
the signal receiving module is used for receiving echo signals reflected by the debris flow area;
and the signal processing module is used for carrying out two-path frequency mixing processing on the echo signal to obtain an intermediate frequency beat signal, acquiring a target Doppler frequency corresponding to the intermediate frequency beat signal, and obtaining the surface flow velocity of the debris flow in the debris flow area based on the target Doppler frequency.
8. The system of claim 7, wherein the signal processing module is further configured to:
filtering and amplifying the echo signal to obtain an intermediate signal;
respectively carrying out frequency mixing processing on the intermediate signal and a first reference signal and a second reference signal to obtain a first frequency mixing signal and a second frequency mixing signal, wherein the first reference signal is the same as the first signal, and the phase difference between the second reference signal and the first reference signal is 90 degrees;
and mixing the first mixing signal and the second mixing signal to obtain the intermediate frequency beat signal.
9. The system of claim 7, wherein the signal processing module is further configured to:
carrying out distance dimension Fourier transform on the intermediate frequency beat signal to obtain Q pieces of one-dimensional distance direction compression processing data;
forming a target matrix with Q rows and N columns by the Q one-dimensional distance direction compression processing data, wherein N is the number of distance direction acquisition points, and Q is the total acquisition cycle number;
performing column-direction Fourier transform on the target matrix to obtain a target frequency domain;
acquiring peak positions in the target frequency domain;
and obtaining the target Doppler frequency corresponding to the intermediate frequency beat signal based on the peak position.
10. The system according to claim 7, characterized in that the radar measurement signal is a sawtooth wave with at least two different frequency sweep periods working alternately.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210648037.XA CN115128592B (en) | 2022-06-08 | 2022-06-08 | Debris flow surface flow velocity monitoring method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210648037.XA CN115128592B (en) | 2022-06-08 | 2022-06-08 | Debris flow surface flow velocity monitoring method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115128592A true CN115128592A (en) | 2022-09-30 |
| CN115128592B CN115128592B (en) | 2023-08-08 |
Family
ID=83377113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210648037.XA Active CN115128592B (en) | 2022-06-08 | 2022-06-08 | Debris flow surface flow velocity monitoring method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115128592B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115840219A (en) * | 2023-02-22 | 2023-03-24 | 北京国信华源科技有限公司 | Debris flow monitoring method and debris flow monitoring equipment |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104007286A (en) * | 2014-06-10 | 2014-08-27 | 上海航征测控系统有限公司 | System for automatically monitoring surface velocity of riverway |
| JP2016090463A (en) * | 2014-11-07 | 2016-05-23 | 横河電子機器株式会社 | Debris flow detection device |
| CN109738885A (en) * | 2019-02-25 | 2019-05-10 | 太原理工大学 | A kind of life detection radar system and method based on random code modulated sinusoid signal |
| CN110632587A (en) * | 2019-10-10 | 2019-12-31 | 南京凌云科技发展有限公司 | Weak moving object monitoring method based on rapid FMCW radar |
| CN110927723A (en) * | 2019-11-11 | 2020-03-27 | 中国地质环境监测院 | Intelligent monitoring and early warning system and method for millimeter wave radar debris flow |
| CN113219449A (en) * | 2021-06-08 | 2021-08-06 | 广州桑瑞科技有限公司 | Slope monitoring radar system |
-
2022
- 2022-06-08 CN CN202210648037.XA patent/CN115128592B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104007286A (en) * | 2014-06-10 | 2014-08-27 | 上海航征测控系统有限公司 | System for automatically monitoring surface velocity of riverway |
| JP2016090463A (en) * | 2014-11-07 | 2016-05-23 | 横河電子機器株式会社 | Debris flow detection device |
| CN109738885A (en) * | 2019-02-25 | 2019-05-10 | 太原理工大学 | A kind of life detection radar system and method based on random code modulated sinusoid signal |
| CN110632587A (en) * | 2019-10-10 | 2019-12-31 | 南京凌云科技发展有限公司 | Weak moving object monitoring method based on rapid FMCW radar |
| CN110927723A (en) * | 2019-11-11 | 2020-03-27 | 中国地质环境监测院 | Intelligent monitoring and early warning system and method for millimeter wave radar debris flow |
| CN113219449A (en) * | 2021-06-08 | 2021-08-06 | 广州桑瑞科技有限公司 | Slope monitoring radar system |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115840219A (en) * | 2023-02-22 | 2023-03-24 | 北京国信华源科技有限公司 | Debris flow monitoring method and debris flow monitoring equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115128592B (en) | 2023-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106405541B (en) | Full-coherent continuous wave Doppler radar and distance and speed measuring method thereof | |
| CN107966688B (en) | Broadband radar target speed ambiguity resolving method based on phase interference technology | |
| CN107607923B (en) | LFMCW radar-based vibration monitoring system and signal processing method | |
| EP2584373B1 (en) | Radar device | |
| US7109916B2 (en) | Device for, in particular bistatic radar applications | |
| CN110837081B (en) | High-speed target detection method based on P/D (Peer-to-Peer) band radar signal fusion processing | |
| KR101092567B1 (en) | Frequency modulated continuous wave rader and detecting method for distance and velocity of moving object using it | |
| WO2021109473A1 (en) | Microwave sensing-based full-field vibration measurement method and system | |
| JP5656505B2 (en) | Radar equipment | |
| CN113009439B (en) | Multi-target detection method based on frequency modulated continuous wave millimeter wave radar | |
| CN114296141A (en) | Multi-target vital sign detector and detection method thereof | |
| US11914021B2 (en) | Velocity measurement device, velocity measurement program, recording medium, and velocity measurement method | |
| CN115128592A (en) | Debris flow surface flow velocity monitoring method and system | |
| KR101527772B1 (en) | METHOD FOR DETECTING TARGET OF FMCW(frequency-modulated continuous wave) RADAR AND FMCW RADAR FOR DETECTING TARGET | |
| CN114200411A (en) | Multi-target speed measurement extension method for MIMO radar | |
| CN110308445B (en) | Imaging method based on vehicle-mounted digital array frequency modulation continuous wave radar | |
| CN109581350B (en) | Radar distance and speed measurement method and device based on time-frequency integral interpolation | |
| CN114217301B (en) | High-precision side slope monitoring radar target detection and distance measurement method | |
| CN112083405B (en) | Target detection method and related device based on mixed waveform | |
| CN114545384A (en) | Integration method and system applied to runway foreign matter detection | |
| US20220061815A1 (en) | Measuring physiological motion using fmcw radar | |
| JP2013113723A (en) | Radar system | |
| CN109782233B (en) | Radar working method and system based on Fourier transform | |
| Siddiq et al. | On phase measurement in FMCW Radar Systems | |
| QasMarrogy et al. | Simulation of Moving Target Indication Radar System Based on VisSim/Comm Application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |