CN116660833A

CN116660833A - Ground penetrating radar control method, device, equipment and storage medium

Info

Publication number: CN116660833A
Application number: CN202310679362.7A
Authority: CN
Inventors: 晋良念; 毛雪; 谢辉玉
Original assignee: Guilin University of Electronic Technology
Current assignee: Guilin University of Electronic Technology
Priority date: 2023-06-08
Filing date: 2023-06-08
Publication date: 2023-08-29

Abstract

The application provides a ground penetrating radar control method, a device, equipment and a storage medium, belonging to the technical field of ground penetrating radars, wherein the method comprises the following steps: the method comprises the steps of generating a frequency sequence group matrix meeting the preset requirement of the ground penetrating radar by utilizing chaotic mapping, optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding emission waveform set, calling a dual-channel narrow-band and broadband transceiver of the ground penetrating radar and a heterogeneous system level chip to emit waveforms to the ground based on the orthogonal discrete frequency coding emission waveform set, receiving reflected waveforms, analyzing and processing the reflected waveforms to obtain a ground penetrating result, improving the working efficiency, meeting the detection requirement of high-speed operation, improving the detection precision of the radar, having unique advantages for spectrum analysis and interference suppression, realizing the balance between detection depth and resolution, and not needing complex signal processing technology.

Description

Ground penetrating radar control method, device, equipment and storage medium

Technical Field

The application relates to the technical field of ground penetrating radars, in particular to a ground penetrating radar control method, a ground penetrating radar control device, ground penetrating radar control equipment and a storage medium.

Background

Ground penetrating radar (Ground Penetrating Radar, GPR) is a non-destructive geophysical prospecting technique for detecting subsurface structures. It detects underground objects and interfaces by emitting high frequency electromagnetic waves and receiving underground reflected waves. Array antennas play a key role in ground penetrating radar systems, and they are responsible for transmitting and receiving electromagnetic signals. The current ground penetrating radar is impulse system, linear frequency modulated continuous wave and step frequency continuous wave. Pulse system radar requires advanced signal processing techniques to improve detection accuracy when processing signals. The linear frequency modulation continuous wave radar can measure for many times in the signal transmitting process, so that the measuring efficiency is improved, but the hardware complexity is higher, and the signal processing is also complex. Step-frequency continuous wave radar is easy to operate and does not require the use of advanced signal processing techniques, does not require many electronic components, but is typically a single measurement.

Disclosure of Invention

The application mainly aims to provide a control method, a control device and a control storage medium for a ground penetrating radar, so that hardware and signal processing complexity of the ground penetrating radar are simplified, multiple measurements of the ground penetrating radar are realized, and detection precision and measurement efficiency are improved.

In order to achieve the above object, the present application provides a ground penetrating radar control method, including:

generating a frequency sequence group matrix meeting the preset requirements of the ground penetrating radar by utilizing chaotic mapping;

optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding emission waveform set;

based on the orthogonal discrete frequency coding emission waveform set, a dual-channel narrow-band transceiver and a heterogeneous system level chip of the ground penetrating radar are called to emit waveforms to the ground, and reflected waveforms are received;

and analyzing and processing the reflected waveform to obtain a ground penetrating result.

Preferably, the generating the frequency sequence group matrix meeting the preset requirement of the ground penetrating radar by using the chaotic mapping includes:

generating a chaotic sequence by using chaotic mapping;

and generating a frequency sequence group matrix meeting the preset requirements of the ground penetrating radar according to the mapping relation based on the chaotic sequence.

Preferably, the generating the chaotic sequence using the chaotic map includes:

acquiring a detection task demand of a ground penetrating radar, determining an antenna frequency according to the detection task demand, and setting an initial value;

and generating a plurality of groups of chaotic sequences according to the antenna frequency and the initial value chaotic map.

Preferably, the generating, based on the chaotic sequence, a frequency sequence group matrix meeting the preset requirement of the ground penetrating radar according to the mapping relation includes:

selecting M chaotic sequences with the length being the target length from the plurality of sets of chaotic sequences to obtain a chaotic sequence submatrix; wherein M is a positive integer;

performing frequency mapping on the chaotic sequence submatrices to obtain a frequency matrix;

performing Fourier transform on the frequency matrix by using a pre-constructed orthogonal discrete frequency coding signal model to obtain an initial frequency sequence group matrix;

calculating peak side lobe ratio of the initial frequency sequence group matrix, and selecting initial frequency sequence group matrix of a preset dimension of a psi group according to the peak side lobe ratio to form a frequency sequence group matrix; wherein, ψ is a positive integer.

Preferably, the optimizing the matrix of the frequency sequence group according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding transmit waveform set includes:

calculating the fitness of the frequency sequence group matrix according to a pre-constructed cost function;

judging whether the adaptability of the frequency sequence group matrix is larger than a preset adaptability;

if yes, judging whether the frequency sequence group matrix accords with a preset optimization rule;

And if the frequency sequence group matrix is consistent with the set of the orthogonal discrete frequency coding transmitting waveform set, taking the frequency sequence group matrix as an optimal frequency sequence group matrix.

Further, after the determining whether the frequency sequence group matrix meets the preset optimization rule, the method further includes:

if the frequency sequence group matrix does not accord with the first W bits of fitness, selecting the frequency sequence group matrix with the first W bits of fitness as a parent of a next generation population, and eliminating the rest frequency sequence group matrix; wherein, W is a positive integer;

determining crossover and mutation probabilities of the father according to the adaptive genetic algorithm and the optimization rule;

generating a new frequency sequence group matrix through crossover and mutation operation according to the crossover and mutation probability, and returning to the step of executing the fitness of calculating the frequency sequence group matrix according to the pre-constructed cost function until the optimal frequency sequence group matrix is output or the maximum iteration number is reached.

Preferably, the ground penetrating radar comprises eleven receiving and transmitting antennas, the eleven receiving and transmitting antennas comprise two four-antenna array units and one three-antenna array unit, each antenna array unit works in a time sharing way, wherein,

triggering two transmitting array elements and two receiving array elements between the four antenna array units simultaneously, and transmitting the two array elements in two times;

The three-antenna array unit firstly triggers two transmitting array elements and receiving array elements at the same time, and then triggers the last transmitting array element.

The application also provides a ground penetrating radar control device, which comprises:

the chaotic mapping module is used for generating a frequency sequence group matrix meeting the preset requirements of the ground penetrating radar by using chaotic mapping;

the optimizing module is used for optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding transmitting waveform set;

the transmitting module is used for calling a dual-channel narrow-band and broadband transceiver of the ground penetrating radar and a heterogeneous system level chip to transmit waveforms to the ground and receiving reflected waveforms based on the orthogonal discrete frequency coding transmitting waveform set;

and the analysis module is used for analyzing and processing the reflected waveform to obtain a ground penetrating result.

The application also provides a ground penetrating radar, comprising a memory and a processor, wherein the memory stores a computer program, and the processor realizes the steps of any one of the methods when executing the computer program.

The application also provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of any of the methods described above.

According to the ground penetrating radar control method, the device, the equipment and the storage medium, the frequency sequence group matrix meeting the preset requirement of the ground penetrating radar is generated through the chaotic mapping, the frequency sequence group matrix is optimized according to the preset genetic algorithm, the orthogonal discrete frequency coding emission waveform set is obtained, the two-channel narrow-band and broadband transceiver of the ground penetrating radar and the heterogeneous system chip are called to emit waveforms to the ground based on the orthogonal discrete frequency coding emission waveform set, the reflected waveforms are received, the reflected waveforms are analyzed and processed, the ground penetrating result is obtained, the working efficiency is improved, the high-speed operation detection requirement is met, the detection precision of the radar is improved, the special advantages are achieved for spectrum analysis and interference suppression, the balance between the detection depth and the resolution is achieved, and the complex signal processing technology is not needed. The signal optimization design method uses the chaotic mapping frequency sequence group matrix as an initial population of an optimization algorithm, optimizes by using a self-adaptive genetic algorithm, greatly improves the convergence rate of the genetic algorithm, improves the global searching capability of the genetic algorithm, and can obtain a transmitting waveform with low side lobe and good orthogonality.

Drawings

FIG. 1 is a flow chart of a ground penetrating radar control method according to an embodiment of the present application;

FIG. 2 is a system block diagram of a ground penetrating radar according to one embodiment of the present application;

fig. 3 is a diagram illustrating an antenna array unit according to an embodiment of the present application;

FIG. 4 is a graph of an autocorrelation function of a signal S1 after being optimally designed using an adaptive genetic algorithm in accordance with one embodiment of the present application;

FIG. 5 is a graph of an autocorrelation function of a signal S2 after being optimally designed using an adaptive genetic algorithm in accordance with one embodiment of the present application;

FIG. 6 is a graph of a cross-correlation function of signals after being optimally designed using an adaptive genetic algorithm in accordance with one embodiment of the present application;

FIG. 7 is a self-ambiguous two-dimensional blur map of a signal after optimization design using an adaptive genetic algorithm in accordance with one embodiment of the present application;

FIG. 8 is a graph of iterative fitness changes of an algorithm for optimizing signals using an adaptive genetic algorithm in accordance with one embodiment of the present application;

FIG. 9 is a block diagram schematically illustrating the structure of a ground penetrating radar control device according to an embodiment of the present application;

fig. 10 is a block diagram schematically illustrating the structure of a ground penetrating radar according to an embodiment of the present application.

The achievement of the objects, functional features and advantages of the present application will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

The application provides a ground penetrating radar control method, wherein an execution main body is a ground penetrating radar, and the ground penetrating radar control method is used for solving the technical problems that hardware and signal processing complexity of the existing ground penetrating radar are high or only single measurement is performed.

Referring to fig. 1, in one embodiment, the present application provides a ground penetrating radar control method, including:

s11, generating a frequency sequence group matrix meeting the preset requirements of the ground penetrating radar by utilizing chaotic mapping;

s12, optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding emission waveform set;

s13, based on the orthogonal discrete frequency coding emission waveform set, a dual-channel narrow-band and broadband transceiver of the ground penetrating radar and a heterogeneous system level chip are called to emit waveforms to the ground, and reflected waveforms are received;

s14, analyzing and processing the reflected waveform to obtain a ground penetrating result.

In this embodiment, the ground penetrating radar includes an array type MIMO ground penetrating radar, which is a geological radar using Multiple Input Multiple Output (MIMO) technology. The radar antenna is provided with a plurality of receiving and transmitting antenna elements to form an array, so that high-precision imaging and positioning of an underground target are realized. The radar system can simultaneously transmit and receive signals in multiple directions, so that the sensitivity and resolution of the radar system are effectively improved, and deeper and smaller underground targets can be detected. In addition, the array MIMO ground penetrating radar has the advantages of strong anti-interference performance, high reliability and the like, and has wide application in the fields of geological exploration, groundwater resource investigation, environmental monitoring and the like.

The MIMO technology can fully utilize the space diversity, waveform diversity and space multiplexing technology to realize the narrow-band high-frequency spectrum utilization rate. The idea can exactly make up for the conventional stepping frequency ground penetrating radar system, realize the ultra-bandwidth of signals and solve the technical difficulties in the dynamic range and high transmitting power.

In one embodiment, the ground penetrating radar comprises eleven transceiving antennas, the eleven transceiving antennas comprise two four-antenna array units and one three-antenna array unit, each antenna array unit works in a time sharing way, wherein,

The MIMO array type ground penetrating radar mainly comprises an antenna array, a main control part, an upper computer part and a ranging part. The structure of the MIMO array type ground penetrating radar can be divided into two parts, namely hardware and software. The hardware part comprises an array antenna, a transmitter, a receiver, a data collector and other devices. The software part comprises data processing and analysis software and can process, analyze and display the acquired radar signals.

The ground penetrating radar of the invention mainly comprises a four-channel acquisition board, a three-channel acquisition board and an array antenna. The acquisition board used was the Zynq series 7020 from Xilinx company. The acquisition board comprises two four-channel acquisition boards and a three-channel acquisition board. Each acquisition board is provided with a plurality of trigger channels, and one trigger channel corresponds to one transmitting antenna. The main control board sends trigger signals to the acquisition board through the channels so as to trigger the transmitting antenna to transmit signals and send radar signals to the target.

The antenna is composed of two four-antenna array units and a three-antenna array unit. The invention can greatly improve the acquisition speed and realize high-speed and high-resolution acquisition by combining a mode of time sharing and simultaneous.

In one embodiment, to meet highway operation, the configuration of the MIMO array is reconfigurable, and as shown in fig. 2 and 3, the transceiver antenna is combined into a linear array with a measurement point spacing of 7.5cm, so as to meet the requirement of multiple transverse measurement lines.

The embodiment adopts a dual-transmission dual-reception mode and a three-transmission three-reception mode. In order to avoid mutual interference between the transmitted signals, the transmitting antenna array is divided into two groups. In each group, in a transmitting period, only one transmitting antenna is triggered by the acquisition board, and meanwhile, two receiving antennas close to each other receive reflected echo signals, and the acquisition board receives two paths of echo data. In this way, two TX transmit antennas transmit signals simultaneously at a guaranteed spacing, and frequency stepping occurs in an opposite manner, guaranteeing that the two transmit signals do not affect each other. Furthermore, two receiving antennas RX corresponding to each transmitting antenna TX. The whole control logic is generated by an FPGA and controls the radio frequency switch of the antenna array.

The waveform generation of the invention is realized by adopting an ADRV9002 dual-channel narrow-band and broadband RF transceiver and a Zynq-7020 heterogeneous SOC platform. After the waveform file after design optimization is obtained, the AD9002 and the Zynq-7020 are connected, and communication is carried out by using an SPI interface. The signal file generated by matlab is then read using Zynq and then converted to coe form to be loaded in the ROM of Zynq. The sampling rate and resolution of the ADRV9002 chip are configured, and the chip is ensured to be synchronous with Zynq-7020. And transmitting signals in the ROM to the ADRV900 for analog-to-digital conversion, externally connecting a power amplifier, and then connecting a transmitting end of the MIMO array antenna for transmitting.

As described in step S11 above, the chaotic map is a nonlinear dynamical system that exhibits unpredictable, random, complex behaviors in time and space. Chaotic maps can be used to describe some natural phenomena such as climate change, fluid dynamics, biological evolution, etc. It is also widely used in the fields of cryptography, communications, image processing, etc. Chaotic mapping is characterized by its sensitivity to initial conditions and parameters, and small variations can lead to completely different results. This behavior is known as the "butterfly effect", i.e. small initial changes in a system can be amplified during the evolution of the system, ultimately leading to completely different results.

The ground penetrating radar preset requirements can comprise requirements of high resolution, depth detection, high signal to noise ratio, high data acquisition speed, low power consumption and the like, and can be set according to actual requirements. High resolution is the imaging capability of ground penetrating radar that is required to have high accuracy and high resolution in order to accurately detect and locate underground objects. Depth detection is the detection of objects deeper into the ground that a ground penetrating radar needs to be able to detect. The signal-to-noise ratio is that the ground penetrating radar needs to have a high signal-to-noise ratio in order to effectively distinguish the target signal from the background noise. The fast data acquisition speed is that the ground penetrating radar needs to be capable of acquiring and processing data in real time so as to monitor and analyze underground objects in real time. The low energy consumption is a feature of the ground penetrating radar that needs to have low power consumption in order to extend battery life or reduce energy consumption.

The frequency sequence group matrix is a matrix made up of a plurality of frequency sequences, each representing a carrier signal in the system. The sequences are mutually orthogonal, so that inter-frequency interference can be avoided. In a multi-carrier communication system, a matrix of frequency sequence sets is typically made up of a plurality of sine waves, each sine wave corresponding to a carrier signal. These sine waves have a fixed frequency difference between them to achieve orthogonality between the different carrier signals. By adjusting the frequency and phase of the sine wave, different frequency sequence groups can be generated, thereby realizing the effective utilization and distribution of frequency resources.

As described in the above step S12, the present application provides an array antenna of a MIMO step frequency ground penetrating radar, which performs rapid multi-channel data acquisition by combining time division and simultaneous mode, and then proposes an orthogonal MIMO radar waveform design method for detecting highway diseases according to the transceiving characteristics of the array antenna. The stepping frequency ground penetrating radar array antenna adopts a special frequency scanning mode to detect underground objects. Which forms a frequency sweep sequence by transmitting a series of successive short pulse signals and gradually increasing the frequency between each pulse signal. Each signal in this sequence interacts with an underground object to produce an echo signal. These echo signals may be received and recorded and then processed by data analysis to obtain information about the subsurface object.

The MIMO radar waveform mainly comprises a quadrature phase code waveform, a quadrature discrete frequency code waveform, a frequency and phase joint code waveform and the like. The orthogonal discrete frequency coding signals can realize the signals of random frequency hopping in the ultra-bandwidth range, the orthogonality among the signals can be realized through reasonably designing the frequency coding, and the distance high resolution can be realized through a low sidelobe signal optimization method. Thus, orthogonal discrete frequency coding is suitable for the transmit signal of the MIMO step frequency ground penetrating radar of the present application.

Orthogonal frequency division multiplexing (OFDM, orthogonal frequency division multiplexing) is a multi-carrier modulation technique that separates a high-speed data stream into multiple low-speed data streams, each modulated onto a separate sub-carrier. The subcarriers are orthogonal, that is, the integral over an integer period of one subcarrier is zero for one period of the other subcarriers. This orthogonality is such that the subcarriers do not interfere with each other. OFDM has many advantages in wireless communication, such as high spectrum utilization, multipath fading resistance, frequency selective fading resistance, ease of implementation, etc. ODFCW (Orthogonal discrete frequency coding waveform) is in essence an extension of OFDW. ODFCW incorporates the concept of time coding, DFCW principle of transmitting each signal in N subbands one by one in the form of sub-pulses.

The optimal design method for the ODFCW mainly comprises a statistical algorithm based on a random sequence or chaotic sequence method, a heuristic algorithm and an accurate algorithm. The sequence-based method can rapidly generate a large number of frequency coding sequences, but the finally generated signals tend to have higher side lobes; the optimization nature of the design method based on statistics is NP problem, so that the operation amount is large, and the iteration time is too long. Therefore, the invention provides an optimization algorithm combining chaos and genetic algorithm, and realizes the rapid and steady design of large-scale signals.

Genetic algorithm (Genetic Algorithm, GA) is a heuristic search algorithm inspired by natural selection and genetic mechanisms in the biology world. The genetic algorithm has stronger global searching capability, and can find a better solution in a larger solution space. For the problem of orthogonal discrete frequency code waveform optimization, the solution space can be quite large, and a genetic algorithm can help find code waveforms with good orthogonality and other performance indexes; in addition, the genetic algorithm adopts random selection, crossing and mutation operation, which is helpful for the algorithm to jump out of the local optimal solution and search for a better global optimal solution. This is particularly important for optimizing orthogonal discrete frequency coded waveforms, as the objective function may have multiple local optimum points. The genetic algorithm has certain advantages in optimizing the orthogonal discrete frequency code waveform, and can effectively find the code waveform with good orthogonality and other performance indexes. Therefore, the genetic algorithm is selected to optimize the frequency codes, and finally the orthogonal discrete frequency code transmitting waveform set is obtained.

In the embodiment, a chaotic sequence is generated by using chaotic mapping, and then a frequency sequence group matrix is generated according to a mapping relation and is used as an initial population. The frequency sequence group is used as a chromosome, so that the calculation resource is greatly saved, and the algorithm iteration speed is improved. The search parameters in each optimizing are adaptively adjusted by using the adaptive genetic algorithm, so that better waveform design and better signal processing effect under the scene of detecting the heterogeneous area of the highway are realized.

As described in the above steps S13-S14, the present embodiment calls the two-channel narrowband, wideband transceiver and heterogeneous system-on-chip of the ground penetrating radar to transmit waveforms to the ground based on the orthogonal discrete frequency coding transmit waveform set, receives reflected waveforms, and then analyzes and processes the reflected waveforms to obtain a ground penetrating result.

According to the control method for the ground penetrating radar, the frequency sequence group matrix meeting the preset requirement of the ground penetrating radar is generated through chaotic mapping, the frequency sequence group matrix is optimized according to the preset genetic algorithm, the orthogonal discrete frequency coding emission waveform set is obtained, the two-channel narrow-band and broadband transceiver of the ground penetrating radar and the heterogeneous system level chip are called to emit waveforms to the ground based on the orthogonal discrete frequency coding emission waveform set, reflected waveforms are received, and analysis processing is carried out on the reflected waveforms, so that the ground penetrating result is obtained, the detection requirement of high-speed operation is met, the detection precision of the radar is improved, the advantages of being unique in terms of spectrum analysis and interference suppression are achieved, the balance between the detection depth and the resolution is achieved, and a complex signal processing technology is not needed. The signal optimization design method uses the chaotic mapping frequency sequence group matrix as an initial population of an optimization algorithm, optimizes by using a self-adaptive genetic algorithm, greatly improves the convergence rate of the genetic algorithm, improves the global searching capability of the genetic algorithm, and can obtain a transmitting waveform with low side lobe and good orthogonality.

In one embodiment, the generating the frequency sequence group matrix meeting the preset requirement of the ground penetrating radar by using the chaotic mapping may specifically include:

generating a chaotic sequence by using chaotic mapping;

The chaotic sequence is generated by utilizing chaotic mapping, and a frequency sequence group matrix meeting the preset requirement of the ground penetrating radar is generated according to the mapping relation based on the chaotic sequence, wherein the chaotic sequence is a digital sequence with randomness and unpredictability, and is a signal generated by a chaotic system. A chaotic system is a nonlinear dynamical system whose behavior appears to be extremely sensitive to initial conditions and parameters, and small variations will lead to completely different results. Therefore, the signals generated by the chaotic system also have the characteristics of randomness, complexity, unrepeatability and the like. The chaotic sequence is usually obtained by discretizing a continuous chaotic signal. By sampling and quantizing the chaotic signal, a digital sequence can be obtained.

In one embodiment, the generating the chaotic sequence by using the chaotic map may specifically include:

The detection task requirements of the ground penetrating radar can relate to requirements on detection depth, resolution, object type, environmental adaptability, signal to noise ratio, data acquisition speed and the like, the antenna frequency can be determined according to the detection task requirements, an initial value can be set, and a plurality of groups of chaotic sequences can be generated according to the antenna frequency and the initial value chaotic mapping.

Detection depth: ground penetrating radar needs to be able to detect underground objects at a depth, typically between tens of meters and hundreds of meters.

Resolution ratio: ground penetrating radar needs to have high resolution in order to accurately detect and locate underground objects. Resolution is typically required to be between a few centimeters and tens of centimeters.

Object type: ground penetrating radar needs to be able to detect different types of underground objects, such as metals, non-metals, hollows, pipelines, etc.

Environmental suitability: ground penetrating radar needs to be adapted to different environmental conditions, such as terrain, soil type, moisture level, etc.

Signal-to-noise ratio: ground penetrating radar needs to have a high signal-to-noise ratio in order to effectively distinguish between target signals and background noise.

Data acquisition speed: ground penetrating radar needs to be able to collect and process data in real time in order to monitor and analyze underground objects in real time.

In one embodiment, the generating, based on the chaotic sequence, a frequency sequence group matrix according to a preset requirement of the ground penetrating radar according to a mapping relation may specifically include:

The embodiment utilizes chaotic mapping to generate a large number of chaotic sequences, then extracts a plurality of groups of chaotic sequences with the length of a required code length from the chaotic sequences, maps the chaotic sequences into frequency sequences according to a frequency mapping relation, substitutes an orthogonal discrete frequency coding signal model, performs Fourier transformation on the orthogonal discrete frequency coding signal model, and calculates peak sidelobe ratio PSLR (peak side lobe ratio) of each group of frequency sequences to obtain a PSLR minimum frequency sequence group matrix.

In one example, this step is specifically:

step A, from a plurality of groups of chaotic sequences C _M,N (i, j) extracting M frequency sequences with the length of K to obtain a chaotic sequence submatrix P _H,K (l,p)；

For example, a ent chaotic map is selected, ent is a piecewise linear map, a random number between 0 and 0.5 is generated by using a random function as an initial value of the chaotic map, and a ent mapping formula is:

x (0) ε (-0.5, 0.5) formula (2);

mu is a control parameter, mu epsilon (0, 2) is usually taken to generate chaotic behaviors, x (N) represents the current value of mapping, namely the state of the system when the time is N, x (n+1) is the state of the system at the next moment, x (0) is the initial value of chaotic mapping, namely the state of the system at the initial moment, n=1, 2, … N and N is the sequence length.

Because the ent chaotic sequence has the best uniform distribution characteristic, the ent sequence is selected to generate a matrix formed by M sequences with the length of N, wherein the coding group C of the chaotic sequence is generated by the ent sequence. M is the number of selected tent sequences, and N is the length of each sequence.

i=1, 2,..m, j=1, 2, n. formula (4);

Step B, for the submatrix P _H,K (l, p) frequency mapping to obtain a frequency matrix F _H,K (l,p)；

The coding scheme mainly has a threshold quantization coding scheme, which is simple but has low uniformity and complexity. Thus selecting a new coding scheme. Considering the frequency range requirements of the conforming signals that need to guarantee the frequency code sets, it is therefore necessary to adjust the frequency code set length according to the selected bandwidth of the ground penetrating radar.

First set an initial value x _m (0) E (0, 1) iteratively generating a M.times.N chaotic sequence matrix C according to the formula (1), taking N E [1, N+999 ]]Formula (5). The first 1000 numbers of each row of the matrix sequence are deleted to reduce the impact of the initial value. Obtaining a chaos sequence matrix C _M,N (i,j)。

Discretized chaotic sequence: the chaos sequence matrix is discretized into an integer sequence, and the chaos sequence matrix obtained by the formula (1) is a floating point number between [0,3], so that discretization is needed.

First of all the slave matrix C _M,N Iteratively extracting H sequences with length of K in (i, j) to form a new chaotic sequence submatrix P _H,K (l, p), H is the number of rows of the sub-matrix and K is the number of columns of the sub-matrix. H e (1, m), K e (1, n), l=1, 2.

Wherein K corresponds to the number of sub-pulses encoded at orthogonal discrete frequencies, k=b/Δf, H corresponds to the initial population of the genetic algorithm, and then, P _H,K Sequencing each row of (l, P) from small to large to obtain a sequence matrix P of the sequence _H ' _,K (l, P) and in the unordered matrix P _H,K Index matrix Q of (l, p) _H,K (l,p)。

Will index matrix Q _H,K Each element in (l, p) is as followsMapping into a frequency coding matrix F _H,K (l,p)，Frequency encoding for the p-th sub-pulse of the first waveform, n ^* F is the number of transitions between sub-pulses ₀ Is the carrier frequency.

At this time, the frequency coding matrix F _H,K (l, p) are M sequences of length K. The antenna array unit adopts an operating mode of simultaneously transmitting L signals, so that the actual signal frequency coding group is a matrix of L-dimension and K-dimension. L corresponds to the number of antenna elements.

Equation (9) is a uniformly discrete randomly ordered frequency coding sequence. Finally obtaining the discrete frequency coding group matrix with the number of H/L and the length of KF _H/L,K And (L, p) is a three-dimensional matrix of L x K x (H/L), namely a chaotic frequency coding group matrix.

Step C: and establishing an orthogonal discrete frequency coding signal model aiming at the frequency matrix, then carrying out Fourier transformation on the orthogonal discrete frequency coding signal model, calculating peak side lobe ratio PSLR of the orthogonal discrete frequency coding signal model, and selecting a PSI group L-K dimensional frequency sequence matrix to form an initialized chaotic discrete frequency coding matrix. The method comprises the following steps:

(1) A transmitting signal model of a chaotic frequency coding group matrix is built, and each frequency coding group T is built according to the model _L,K Is of discrete frequency code signal sig _l (t)，l＝1,2,...L。

(2) Fourier transforming the transmitted signals of all the frequency code sequence groups to obtain a spectrum signal matrix of each frequency code sequence group.

(3) And (3) calculating peak sidelobe ratio PSLR (peak side lobe ratio) in the spectrum signal matrix, and selecting a plurality of discrete frequency coding sequences with the minimum peak sidelobe ratio as a finally selected frequency coding sequence group, namely an initial population of a genetic algorithm.

For example, for frequency coding sequence T _L,K Constructing an orthogonal discrete frequency coding signal model:

let the number of MIMO radar transmitting array elements be L, the number of sub-pulses be U, then T _L,K The discrete frequency coding waveform set formed by the corresponding L frequency hopping sequences is as follows:

wherein,,

t is the sub-pulse width, U is the number of sub-pulses, LTo transmit the array element number, f _l.p ＝f ₀ The + (U-1) Δf is the frequency encoding of the U-th sub-pulse in the first waveform, and Δf=1/T is the frequency step interval, u=1, 2,...

Fourier transforming the signal to obtain a frequency domain signal:

f _r is the frequency at which the frequency is to be determined,is->Is a fourier transform of (a).

Finally calculate SIG (f) _r ) Is a PSLR of (C).

|y ₀ I is the maximum amplitude of the main lobe, y _k The amplitude of each signal outside the main lobe.

And finally, selecting the frequency coding sequence with the minimum PSLR as an initial population.

In one embodiment, the optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain the orthogonal discrete frequency coding transmit waveform set may specifically include:

The invention optimizes the frequency sequence group matrix by utilizing the self-adaptive genetic algorithm to obtain the orthogonal discrete frequency coding transmitting signal set with good orthogonality.

For example, the step includes:

firstly, a proper cost function is established, and as the local radar antenna array needs to transmit 2 or 3 signals simultaneously, good orthogonality between the signals needs to be ensured. And establishing a cost function by using a minimized peak sidelobe criterion, wherein the cost function mainly comprises the self-correlation sidelobe energy and the cross-correlation energy, and the sidelobe peak value of the self-correlation function and the peak value of the cross-correlation function are also considered.

And then optimizing the frequency coding by utilizing a self-adaptive genetic algorithm, wherein the optimized individual is a frequency coding sequence group of a single transmitting waveform set, and the optimized population is a plurality of groups of frequency coding sequences with lower PSLR. The adaptive genetic algorithm increases the searching capability of the algorithm to the global optimal solution by adaptively adjusting the number of variation points, thereby improving the searching efficiency and the global searching capability of the algorithm. The main steps of the optimization are as follows:

establishing a cost function according to a minimized peak sidelobe criterion;

calculating the adaptability of the frequency coding set, judging whether the frequency coding set meets the optimization criterion, if so, outputting the optimal frequency coding set, otherwise, continuing to optimize;

and calculating the fitness of each individual according to the cost function, selecting the individual with higher fitness as the parent of the next generation population, wherein the probability of the selected individuals is higher, and the individuals with lower fitness are eliminated.

Determining crossover and mutation probabilities by utilizing an adaptive genetic algorithm criterion, and generating a new individual through crossover and mutation;

and (5) again evaluating whether the new population fitness meets the optimization criterion, if so, stopping iterating to output the optimal frequency coding group, and otherwise, continuing to optimize.

For example, a cost function is first established:

for ground penetrating radars, the autocorrelation function of the discrete frequency coded signal should have as low side lobes as possible, while the cross-correlation function value should be as small as possible, i.e. should have the following properties:

p+.q, p, q=1, 2,..l formula (15);

in practice, the cross-correlation of the signals cannot be zero, so engineering tends to use the following criteria to measure whether the signals have close to orthogonality.

Minimizing peak sidelobe criteria:

(1) Minimizing autocorrelation peak sidelobe levels

(2) Minimizing cross-correlation peak levels

According to the minimized peak sidelobe criterion, the cost function should consider both the autocorrelation sidelobe energy and the cross-correlation energy, and the sidelobe peak of the autocorrelation function and the peak of the cross-correlation function, i.e., the cost function can be expressed as

The cost function of the adaptive genetic algorithm is therefore:

next, an initial population is established:

and C, selecting a psi group frequency sequence from the frequency coding sequence group in the step A as an initial population of a genetic algorithm, wherein each individual is a matrix formed by L frequency sequences with the length of K, and the initial population of the genetic algorithm is as follows:

wherein the chromosome is:

in the above formula, L is the number of transmitting array elements, K is the number of sub-pulses, and ψ is the population number.

Then calculating the fitness of the individual according to the cost function, judging whether the fitness meets the optimization criterion, and outputting the optimal individual and the optimal solution thereof if the fitness meets the optimization criterion; and if the result is met, outputting the optimal individual and the optimal solution represented by the optimal individual, and ending the calculation.

In one embodiment, after the determining whether the frequency sequence group matrix meets the preset optimization rule, the method further includes:

The self-adaptive genetic algorithm is different from the traditional algorithm in that the fixed search parameters are adopted, and the self-adaptive search parameter adjustment mode is adopted for crossover and mutation, so that the self-adaptive genetic algorithm is more suitable for large-scale frequency coding waveform optimization compared with the traditional genetic algorithm. Besides, the self-adaptive genetic algorithm has strong controllability and stronger global optimizing capability, and is more suitable for frequency coding optimization in a large-bandwidth scene, so that the self-adaptive genetic algorithm is selected for optimization.

The adaptive genetic algorithm (Adaptive Genetic Algorithm, AGA) is an algorithm capable of adaptively adjusting parameters in the genetic algorithm, and has the following advantages compared with the traditional genetic algorithm:

the convergence speed is high: traditional genetic algorithms require manual parameter adjustment, whereas AGA can automatically adjust parameters, so that the algorithm finds a better solution in a shorter time, and the convergence speed is faster.

Higher search efficiency: in conventional genetic algorithms, the setting of parameters may be unreasonable, resulting in inefficient algorithm searches. The AGA can adaptively adjust parameters, so that the searching efficiency of the algorithm is higher.

The method is more adaptive to different problems: in conventional genetic algorithms, the setting of algorithm parameters may need to depend on the nature of the different problems, requiring constant manual adjustment of the parameters. The AGA can adaptively adjust parameters, is more adaptive to different problems, and reduces the workload of algorithm designers.

Better global search capability: the traditional genetic algorithm may be trapped in a locally optimal solution, and the AGA can adaptively adjust algorithm parameters, so that the searching capability of the algorithm on the globally optimal solution is increased, and the globally optimal solution is easier to find.

The adaptability is strong: the conventional genetic algorithm may have the problems that convergence is slow and an optimal solution cannot be searched due to unreasonable parameter setting, and the AGA can adaptively adjust parameters and has stronger adaptability, so that the adaptive genetic algorithm is selected as an optimization algorithm.

In this embodiment, if the frequency sequence group matrix does not conform to a preset optimization rule, the optimization is continued.

Next, fitness function values of all individuals are calculated:

will T _L,K (i) Substitution signal model

Then split intoThe peak value of the side lobe of the autocorrelation function and the peak value of the cross-correlation function are obtained, the autocorrelation side lobe energy and the cross-correlation energy are obtained, and the weight w is determined through multiple experiments ₁ ,w ₂ ,w ₃ ,w ₄ Is a value of (2). And finally, obtaining a moderate value according to the cost function.

The regenerated individuals are selected according to the fitness, the selected probability is higher, and the individuals with high fitness can be eliminated.

Determining crossover probability and mutation probability of the adaptive genetic algorithm according to the following formula:

P _c for crossover probability, P _m For the variation probability, f _max Is the maximum fitness value in the population; f (f) _avg Is the average fitness value within the population; f is the larger fitness value of the two individuals to be crossed; f' is the fitness value of the individual to be mutated. k (k) ₁ ,k ₂ ,k ₃ Is an arbitrary constant.

Then crossover and mutation are performed according to the calculated crossover probability and mutation probability to generate new individuals. And finally judging whether the fitness value of the individual meets the requirement, and if so, stopping iteration.

In order to obtain a waveform set with good orthogonality, the method sets an optimization criterion by using a design cost function of minimizing peak sidelobes, calculates the fitness of each individual in the frequency sequence group matrix, judges that the fitness meets the optimization criterion, outputs a frequency sequence group if the fitness meets the optimization criterion, and continues to optimize if the fitness meets the optimization criterion. And then determining search parameters according to a self-adaptive genetic algorithm formula, continuously performing crossover and mutation to generate a new population, and then evaluating the fitness of the individual again until the optimization condition is reached or the iteration times are reached, so as to obtain a frequency sequence group with good orthogonality.

An example of the simulation of the transmission waveform of the MIMO array type ground penetrating radar system is given below, and the performance thereof is analyzed.

Table 1: the system configuration parameters are as follows:

according to the invention, the frequency sequence coding group is utilized to improve the iteration speed for optimizing the individual, so that the calculation time is saved, and the standard genetic algorithm needs to optimize the individual by using each frequency code, and each frequency code needs to be converted into a binary code, so that the calculation time is overlong. And then, the self-adaptive variational point genetic algorithm is utilized to optimize the system, so that the system is more suitable for the actual application requirements of the ground penetrating radar, the target detection capability of the system is greatly improved, and the working time of the system is reduced.

And carrying out simulation on the ground penetrating radar signal design algorithm for 50 times, and selecting an average value as a result value. And gives the analytical values using the chaotic map alone and the modified genetic algorithm alone.

Table 2: the chaos mapping is singly used, the genetic algorithm is singly used, and the effect, the autocorrelation peak side lobe and the cross correlation side lobe level comparison of the self-adaptive variational point genetic algorithm based on the chaos mapping are used

As can be seen from Table 2, the autocorrelation side lobe peak (ASP) and the cross Correlation Peak (CP) of the orthogonal discrete frequency coded signal designed by the method of the invention are improved, wherein the maximum autocorrelation side lobe peak is improved by 4.54dB compared with the traditional algorithm, and the cross correlation peak is improved by 14.07dB. The average autocorrelation sidelobe peak is increased by 3.19dB, and the average cross correlation peak is increased by 11.85dB.

Referring to fig. 4, 5 and 6, it can be seen that the frequency sequence generated by the chaotic map is used as an initial population, and is optimized by using an adaptive genetic algorithm, so that the chaotic map still has good adaptability under a large-scale signal. Compared with the signal generated by simply utilizing the chaotic sequence, the method has better autocorrelation performance and cross correlation performance. Therefore, the signal design method is suitable for the detection of the array type ground penetrating radar.

Referring to fig. 7, it can be seen that the fuzzy function of the signal presents a pin shape, so that the fuzzy function has good autocorrelation performance, and is beneficial to improving the target detection capability.

Referring to fig. 8, it can be seen that, for the iterative variation time curve of the signal design method, it can be seen that at the 45 th generation, the algorithm converges to the optimal fitness, which proves that the optimization algorithm can realize the rapid and steady design of the large-scale signal, and the computing resource is saved and the iteration speed is improved while ensuring the good correlation performance.

The method for designing and generating the orthogonal MIMO ground penetrating radar waveform for detecting the highway heterogeneous region is suitable for the ground penetrating radar in a wide bandwidth application scene, can quickly and robustly generate waveforms with longer code length, and compared with the traditional statistical optimization algorithm, the method for generating the initial population by adopting chaotic mapping, greatly reduces the search space of the algorithm, saves calculation resources, and is more suitable for the design requirement of a transmitting waveform set with different bandwidths without detecting depth by utilizing the adaptive genetic algorithm. Compared with the prior art, the invention has the following advantages;

1. the step frequency MIMO antenna array can realize high-speed multichannel data acquisition. The MIMO array is introduced into the stepping frequency ground penetrating radar, so that the rapid acquisition of the multi-measuring-point sparse array is realized, technical support is provided for the high-resolution high-speed acquisition of the ground penetrating radar in the market, and the pain point with low resolution caused by the single measuring point acquisition of the traditional stepping frequency system is solved.

2. A set of orthogonal MIMO transmit waveforms of longer code length is rapidly generated. The chaotic mapping is utilized to generate the initial low PSLR frequency coding sequence, and the initial low PSLR frequency coding sequence is used as an initial population, so that the convergence rate of a genetic algorithm is greatly improved, the global searching capability of the genetic algorithm is improved, and the transmitting waveform with good low side lobe orthogonality can be obtained.

3. A set of more consistently superior orthogonal discrete frequency coded waveforms is generated. The search parameters are adaptively adjusted in the iterative process by utilizing the adaptive genetic algorithm, so that a local optimal solution is avoided, a better solution is obtained, and the convergence rate is improved.

Referring to fig. 9, in an embodiment of the present application, there is further provided a ground penetrating radar control device, including:

the chaotic mapping module 11 is used for generating a frequency sequence group matrix meeting the preset requirements of the ground penetrating radar by using chaotic mapping;

the optimizing module 12 is configured to optimize the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coding transmit waveform set;

the transmitting module 13 is used for calling a dual-channel narrow-band and broadband transceiver of the ground penetrating radar and a heterogeneous system level chip to transmit waveforms to the ground and receiving reflected waveforms based on the orthogonal discrete frequency coding transmitting waveform set;

And the analysis module 14 is used for analyzing and processing the reflected waveforms to obtain ground penetrating results.

As described above, it may be understood that each component of the ground penetrating radar control device provided in the present application may implement a function of any one of the ground penetrating radar control methods described above, and specific structures are not described again.

Referring to fig. 10, in an embodiment of the present application, there is further provided a ground penetrating radar, an internal structure of which may be as shown in fig. 10. The ground penetrating radar comprises a processor and a memory which are connected through a system bus. Wherein the processor of the ground penetrating radar is configured to provide computing and control capabilities. The memory of the ground penetrating radar comprises a storage medium and an internal memory. The storage medium stores an operating system, computer programs, and a database. The memory provides an environment for the execution of computer programs in the storage media. The computer program, when executed by a processor, implements a ground penetrating radar control method.

The processor executes the ground penetrating radar control method, and the method comprises the following steps:

In one embodiment of the present application, there is also provided a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements a ground penetrating radar control method, the method comprising:

Those skilled in the art will appreciate that implementing all or part of the above-described methods may be accomplished by way of a computer program stored on a computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium provided by the present application and used in embodiments may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual speed data rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

In summary, the application has the following maximum beneficial effects:

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, apparatus, article, or method. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, apparatus, article or method that comprises the element.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the application, and all equivalent structures or equivalent processes using the descriptions and drawings of the present application or directly or indirectly applied to other related technical fields are included in the scope of the application.

Claims

1. A ground-penetrating radar control method, characterized in that it includes:

A frequency sequence matrix that meets the preset requirements of ground penetrating radar is generated using chaotic mapping.

The frequency sequence group matrix is optimized according to a preset genetic algorithm to obtain an orthogonal discrete frequency coded transmission waveform set;

Based on the orthogonal discrete frequency encoded transmitted waveform set, the dual-channel narrowband and broadband transceivers and heterogeneous system-on-a-chip of the ground penetrating radar are invoked to transmit waveforms to the ground and receive reflected waveforms.

The reflected waveform is analyzed and processed to obtain the ground exploration results.

2. The method according to claim 1, characterized in that, generating a frequency sequence group matrix that meets the preset requirements of ground penetrating radar using chaotic mapping includes:

Generating chaotic sequences using chaotic mapping;

Based on the chaotic sequence, a frequency sequence group matrix that meets the preset requirements of ground penetrating radar is generated according to the mapping relationship.

3. The method according to claim 2, characterized in that, generating a chaotic sequence using chaotic mapping includes:

Obtain the detection mission requirements of the ground penetrating radar, determine the antenna frequency and set the initial value based on the detection mission requirements;

Multiple chaotic sequences are generated based on the antenna frequency and initial value through chaotic mapping.

4. The method according to claim 3, characterized in that, the step of generating a frequency sequence group matrix that conforms to the preset requirements of ground penetrating radar based on the chaotic sequence and according to the mapping relationship includes:

From the plurality of chaotic sequences, select M chaotic sequences of the target length to obtain a chaotic sequence submatrix; wherein M is a positive integer;

Frequency mapping is performed on the chaotic sequence submatrix to obtain the frequency matrix;

The frequency matrix is subjected to Fourier transform using a pre-constructed orthogonal discrete frequency coded signal model to obtain an initial frequency sequence group matrix;

Calculate the peak-to-sidelobe ratio of the initial frequency sequence group matrix, and select Ψ groups of initial frequency sequence group matrices of preset dimensions according to the peak-to-sidelobe ratio to form a frequency sequence group matrix; wherein, Ψ is a positive integer.

5. The method according to claim 1, characterized in that, the step of optimizing the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coded transmission waveform set includes:

The fitness of the frequency sequence group matrix is calculated based on a pre-constructed cost function;

Determine whether the fitness of the frequency sequence group matrix is greater than a preset fitness.

If so, determine whether the frequency sequence group matrix conforms to the preset optimization rules;

If the conditions are met, the frequency sequence group matrix is taken as the optimal frequency sequence group matrix to obtain the orthogonal discrete frequency coded transmission waveform set.

6. The method according to claim 5, characterized in that, after determining whether the frequency sequence group matrix conforms to the preset optimization rule, it further includes:

If the conditions are not met, the frequency sequence matrix with the highest fitness (ranked in the top W positions) is selected as the parent of the next generation population, and the remaining frequency sequence matrices are eliminated; where W is a positive integer.

The crossover and mutation probabilities of the parent generation are determined according to the adaptive genetic algorithm and the optimization rules.

Based on the crossover and mutation probabilities, a new frequency sequence group matrix is generated through crossover and mutation operations, and the step of calculating the fitness of the frequency sequence group matrix according to the pre-constructed cost function is returned until the optimal frequency sequence group matrix is output or the maximum number of iterations is reached.

7. The method according to claim 1, characterized in that the ground-penetrating radar comprises eleven transceiver antennas, the eleven transceiver antennas comprising two four-antenna array units and one three-antenna array unit, each antenna array unit operating in a time-division multiplexing manner, wherein,

The four antenna array elements simultaneously trigger two transmitting elements and one receiving element, and transmit in two separate steps;

The three-antenna array unit first triggers two transmitting elements and the receiving element simultaneously, and then triggers the last transmitting element.

8. A ground-penetrating radar control device, characterized in that it comprises:

The chaotic mapping module is used to generate a frequency sequence group matrix that meets the preset requirements of ground penetrating radar using chaotic mapping.

The optimization module is used to optimize the frequency sequence group matrix according to a preset genetic algorithm to obtain an orthogonal discrete frequency coded transmission waveform set;

The transmission module is used to transmit waveforms to the ground based on the orthogonal discrete frequency encoded waveform set, and to call the dual-channel narrowband and broadband transceivers and heterogeneous system-on-a-chip of the ground penetrating radar, and to receive reflected waveforms.

The analysis module is used to analyze and process the reflected waveform to obtain the ground exploration results.

9. A ground-penetrating radar, characterized in that it comprises:

processor;

Memory;

The memory stores a computer program, and the processor executes the computer program to implement the ground-penetrating radar control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the ground-penetrating radar control method according to any one of claims 1-7.