Multi-channel chaotic ground penetrating radar device for urban road disease detection

Abstract

The invention belongs to the technical field of ground penetrating radar detection, particularly relates to a multi-channel chaotic ground penetrating radar device for urban road disease detection, and solves the technical problems that an existing multi-channel pulse ground penetrating radar is poor in anti-jamming capability and multiple channels cannot work in parallel. Wherein the signal generation unit comprises a pulse signal generation module and a chaotic pulse signal generation module; the transmitting and receiving unit comprises N transmitting and receiving subunits; each transmitting and receiving subunit comprises a local oscillator signal generator, a three-path power divider, a first / second / third frequency mixer, a first / second power amplifier, a first / second transmitting antenna, a receiving antenna, a low-noise amplifier and a signal acquisition subunit; the signal matching unit comprises N signal matching subunits, and each signal matching subunit comprises a pulse detector and a pulse interval matching module; the clock control unit is connected to the pulse signal generation module, the chaotic pulse signal generation module, the signal matching subunit and the transmitting and receiving subunit.

Description

Technical Field

[0001] The invention relates to the technical field of ground penetrating radar detection, and in particular to a multi-channel chaotic ground penetrating radar device for urban road disease detection. Background Art

[0002] With the rapid development of urbanization and the continuous development of urban underground space resources, urban road collapse accidents occur frequently. A large number of road quality surveys have found that road collapse is closely related to underground hidden diseases. Ground Penetrating Radar (GPR) is a non-destructive and rapid detection technology that uses electromagnetic wave reflection to determine the distribution of underground media. It has become the preferred method for road disease detection. In recent years, in order to meet the requirements of rapid road detection without affecting normal traffic, a series of vehicle-mounted ground penetrating radars have been successfully developed. This type of vehicle-mounted ground penetrating radar uses multi-channel or antenna array type. The detection vehicle can cover the entire lane in the horizontal direction at the same time when driving in a single trip. The amount of data information is large at one scan and the detection speed is fast.

[0003] However, the existing technology has the following problems: Most of the existing multi-channel ground penetrating radars adopt a pulse system, and their anti-interference ability is limited, which is mainly reflected in: 1. They are susceptible to electromagnetic interference from the surrounding environment. Due to the diverse functions and complex composition of urban roads, the echo signal of the ground penetrating radar will be affected by many interference sources above and below the ground, such as pipelines, cables, optical cables and other structures inside the road, cables and signal transmitters installed above the road, etc., resulting in a low signal-to-noise ratio, which makes it very difficult to detect and identify targets. 2. Multi-channel ground penetrating radar is equivalent to multiple single-channel ground penetrating radars working at the same time. Each channel will not only receive the echo signal of the channel, but may also receive the transmission signal of other channels, resulting in misjudgment. This mutual interference between the channels will seriously affect the detection effect of the multi-channel ground penetrating radar. In order to avoid crosstalk between channels, most existing technologies use time division multiplexing (CN202211245313.4, CN201611098515.5), which only allows one channel to work at each moment. However, when multi-channel ground penetrating radar works on a high-speed moving platform such as a vehicle or an aircraft, it will cause a large measurement error. Based on this, it is necessary to invent a ground penetrating radar device with strong anti-interference ability and multi-channel parallel operation for urban road disease detection to solve the above problems existing in the existing ground penetrating radar system. Summary of the invention

[0004] In order to overcome the technical defects of the existing multi-channel pulse ground penetrating radar, that is, the anti-interference ability is poor and the multiple channels cannot work in parallel, the present invention provides a multi-channel chaotic ground penetrating radar device for urban road disease detection.

[0005] The present invention provides a multi-channel chaotic ground penetrating radar device for urban road disease detection, comprising a signal generating unit, a transmitting and receiving unit, a signal matching unit, a signal processing unit, a clock control unit and a display unit;

[0006] The signal generating unit includes a pulse signal generating module for generating N-channel periodic pulse signals and a chaotic pulse signal generating module for generating N-channel chaotic pulse signals;

[0007] The transmitting and receiving unit includes N transmitting and receiving subunits, each of which includes a local oscillator signal generator, a three-way power divider, a first mixer, a second mixer, a third mixer, a first power amplifier, a second power amplifier, a first transmitting antenna, a second transmitting antenna, a receiving antenna, a low noise amplifier and a signal acquisition subunit; the local oscillator signal generator generates three local oscillator signals through the three-way power divider, and the three local oscillator signals are respectively connected to the first mixer, the second mixer and the third mixer, the output end of the first mixer is connected to the input end of the first transmitting antenna through the first power amplifier, and the output end of the second mixer is connected to the input end of the second transmitting antenna through the second power amplifier; the output end of the receiving antenna is connected to the input end of the third mixer through the low noise amplifier; N periodic pulse signals are respectively connected to the first mixers of the N transmitting and receiving subunits, and N chaotic pulse signals are respectively connected to the second mixers of the N transmitting and receiving subunits. The first transmitting antenna and the second transmitting antenna are used to transmit electromagnetic waves to the ground, and the receiving antenna is used to receive echo signals; the output end of the third mixer is used to collect signals through the signal acquisition subunit;

[0008] The signal matching unit includes N signal matching subunits, each signal matching subunit includes a pulse detector and a pulse interval matching module, the output end of the pulse detector is connected to the input end of the pulse interval matching module, N-way periodic pulse signals are respectively connected to the pulse detectors and pulse interval matching modules of the N signal matching subunits, N-way chaotic pulse signals are respectively connected to the pulse detectors and pulse interval matching modules of the N signal matching subunits, the output ends of the N signal acquisition subunits are connected to the pulse detectors of the N signal matching subunits, the pulse detector is provided with an amplitude threshold and a width threshold, when the number of sampling points of the input signal is greater than the width threshold and the amplitude of the collected signal is greater than the amplitude threshold, it is considered that the input signal is a pulse echo signal, and the pulse detector inputs the pulse echo signal to the pulse interval matching module; the pulse interval matching module receives the periodic pulse signal The signal and chaotic pulse signal are matched, and the time interval between the periodic pulse signal and the chaotic pulse signal is calculated. The pulse interval matching module also receives the pulse echo signal detected by the pulse detector. When the time interval between the two pulse echo signals before and after is the same as the time interval between the periodic pulse signal and the chaotic pulse signal, it is considered that the signal matching is successful. The signal matching subunit inputs the two successfully matched pulse echo signals before and after to the signal processing unit for processing. The signal processing unit calculates the emission time and the echo time of the periodic pulse signal to obtain the first delay time, and then calculates the emission time and the echo time of the chaotic pulse signal to obtain the second delay time. The signal processing unit calculates the average delay time according to the first delay time and the second delay time to obtain the final time delay, and then calculates the target distance according to the time delay. The signal processing unit sends the target distance to the display unit in real time for display.

[0009] The clock control unit is respectively connected to the pulse signal generating module, the chaotic pulse signal generating module, N signal matching subunits and N transmitting and receiving subunits; the clock control unit is connected to the pulse signal generating module and the chaotic pulse signal generating module, and is used to provide a clock on the one hand, and to ensure that the pulse signal generating module and the chaotic pulse signal generating module transmit signals at the same time on the other hand; the clock control unit is connected to the N transmitting and receiving subunits, and is used to ensure that the signal acquisition subunits in the N transmitting and receiving subunits achieve simultaneous sampling; the clock control unit is connected to the N signal matching subunits, and is used to provide a clock for each pulse detector, and ensure that the N signal matching subunits work at the same time.

[0010] Preferably, the pulse signal generating module includes a first pulse signal generator and a first N-way power divider, the first pulse signal generator is used to generate a periodic pulse signal, and generates N-way periodic pulse signals through the first N-way power divider; the chaotic pulse signal generating module includes a chaotic mapping module, a counter, a comparator, a second pulse signal generator, a second N-way power divider and N electrical delay lines, the chaotic mapping module is used to generate a random number in the range of [0,1], the counter starts counting from zero, the output end of the chaotic mapping module and the output end of the counter are both connected to the input end of the comparator, the output end of the comparator is connected to the input end of the second pulse signal generator, and the second pulse signal generator is connected to the second N The first power divider is connected to the second power divider, and N chaotic pulse signals are generated through the second N power divider. The N chaotic pulse signals are output after passing through N electrical delay lines respectively. The output of the chaotic mapping module and the output input comparator of the counter are compared. When the output of the counter is greater than the output of the chaotic mapping module, the second pulse signal generator is triggered to generate a new chaotic pulse signal. The new chaotic pulse signal is closed-loop fed back to the input end of the counter and the chaotic mapping module. The rising edge triggers the reset counter to zero, and updates the chaotic mapping module output to enter the next state. The chaotic mapping module adopts an improved Logistic mapping and a type I third-order Chebychev polynomial to generate a composite chaotic map.

[0011] The calculation formula of the improved Logistic mapping is:

[0012] ;

[0013] The third-order Chebychev polynomial of type I is:

[0014] Then the calculation formula of the composite chaotic map is: .

[0015] The intervals of each periodic pulse signal and each chaotic pulse signal vary randomly within each pulse repetition period. After the periodic pulse signal is up-converted by the first mixer and amplified by the first power amplifier, it transmits the signal to the ground through the first transmitting antenna; after the chaotic pulse signal is up-converted by the second mixer and amplified by the second power amplifier, it transmits the signal to the ground through the second transmitting antenna; when the transmission signals of the first transmitting antenna and the second transmitting antenna to the ground encounter different underground medium interfaces, they are reflected to form echo signals, and the echo signals are down-converted by the receiving antenna, the low noise amplifier, and the mixer, and then enter the signal acquisition subunit for acquisition. After the N channels are sampled in parallel, the data is input into the N signal matching subunits for pulse detection and pulse interval matching. The N signal matching subunits are processed in parallel. If the matching is successful, the pulse echo signal enters the signal processing unit for processing, and finally displayed in real time on the display unit. Through the signal matching subunit, the signal interference of other channels and the electromagnetic interference in the environment are eliminated, so that each channel can work simultaneously without time division multiplexing. The clock control unit generates a reference clock for controlling the clocks of the signal generating unit, the signal acquisition unit, and the signal matching unit. The signal generation unit, signal matching unit, signal processing unit and clock control unit are all implemented on FPGA. In the chaotic pulse signal generation module, since the cross-correlation between the delayed chaotic pulse signal and the non-delayed chaotic pulse signal is small, the N chaotic pulse signals generated are orthogonal to each other. The trigger clocks of the first pulse signal generator and the second pulse signal generator are synchronized, and the intervals between the periodic pulse signal and the chaotic pulse signal change randomly within each pulse repetition period. The N transmitting and receiving subunits can change the center frequency of the transmitting signal by adjusting the local oscillator frequency of the local oscillator signal generator.

[0016] Preferably, the pulse repetition period of the first pulse signal generator and the second pulse signal generator is the same, and the maximum delay time of the electric delay line is less than the pulse repetition period; within the pulse repetition period of the first pulse signal generator and the second pulse signal generator, the intervals between the periodic pulse signal and the chaotic pulse signal change randomly.

[0017] Compared with the prior art, the technical solution provided by the present invention has the following technical effects: the transmitting signal of the ground penetrating radar device described in the present invention is a periodic pulse signal-chaotic pulse signal pair with random intervals, and the receiving end determines whether it is an echo signal from the pulse signal pair through a pulse interval matching method; the device combines the characteristics of traditional pulse radar and chaotic radar, and has both the characteristics of long detection distance of pulse radar and strong anti-interference ability of chaotic radar, which can ensure the detection depth of the ground penetrating radar and the resistance to external electromagnetic interference and interference from different channels, and realize the ground penetrating radar in a complex urban environment. Rapid and accurate road disease detection; multiple channels of the device can flexibly set the working frequency band, on the one hand, further reduce the interference between channels, on the other hand, through the effective combination of high, medium and low frequency bands, it can take into account both the detection depth and detection accuracy, and provide richer and more accurate underground disease information. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 The present invention is a schematic structural diagram of a multi-channel chaotic ground penetrating radar device for urban road disease detection according to an embodiment of the present invention.

[0021] In the figure: 1. local oscillator signal generator; 2. three-way power divider; 3. first mixer; 4. second mixer; 5. third mixer; 6. first power amplifier; 7. second power amplifier; 8. first transmitting antenna; 9. second transmitting antenna; 10. receiving antenna; 11. low noise amplifier; 12. signal acquisition subunit; 13. pulse detector; 14. pulse interval matching module; 15. signal processing unit; 16. display unit; 17. clock control unit; 18. first pulse signal generator; 19. first N-way power divider; 20. chaos mapping module; 21. counter; 22. comparator; 23. second pulse signal generator; 24. second N-way power divider. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0023] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0025] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] In one embodiment, Figure 1 As shown, a multi-channel chaotic ground penetrating radar device for urban road disease detection is disclosed, including a signal generating unit, a transmitting and receiving unit, a signal matching unit, a signal processing unit 15, a clock control unit 17 and a display unit 16;

[0027] The signal generating unit includes a pulse signal generating module for generating N-channel periodic pulse signals and a chaotic pulse signal generating module for generating N-channel chaotic pulse signals;

[0028] The transmitting and receiving unit includes N transmitting and receiving subunits, each of which includes a local oscillator signal generator 1, a three-way power divider 2, a first mixer 3, a second mixer 4, a third mixer 5, a first power amplifier 6, a second power amplifier 7, a first transmitting antenna 8, a second transmitting antenna 9, a receiving antenna 10, a low noise amplifier 11 and a signal acquisition subunit 12; the local oscillator signal generator 1 generates three local oscillator signals through the three-way power divider 2, and the three local oscillator signals are respectively connected to the first mixer 3, the second mixer 4 and the third mixer 5, and the output end of the first mixer 3 is connected to the first transmitting antenna 8 through the first power amplifier 6. The input end of the transmitting antenna 8, the output end of the second mixer 4 is connected to the input end of the second transmitting antenna 9 through the second power amplifier 7; the output end of the receiving antenna 10 is connected to the input end of the third mixer 5 through the low noise amplifier 11; N-way periodic pulse signals are respectively connected to the first mixers 3 of the N transmitting and receiving subunits, and the N-way chaotic pulse signals are respectively connected to the second mixers 4 of the N transmitting and receiving subunits. The first transmitting antenna 8 and the second transmitting antenna 9 are used to transmit electromagnetic waves to the ground, and the receiving antenna 10 is used to receive echo signals; the output end of the third mixer 5 is used for signal acquisition through the signal acquisition subunit 12;

[0029] The signal matching unit includes N signal matching subunits, each of which includes a pulse detector 13 and a pulse interval matching module 14. The output end of the pulse detector 13 is connected to the input end of the pulse interval matching module 14. N periodic pulse signals are respectively connected to the pulse detectors 13 and pulse interval matching modules 14 of the N signal matching subunits. N chaotic pulse signals are respectively connected to the pulse detectors 13 and pulse interval matching modules 14 of the N signal matching subunits. The output ends of the N signal acquisition subunits 12 are connected to the pulse detectors 13 of the N signal matching subunits. The pulse detector 13 is provided with an amplitude threshold and a width threshold. When the number of sampling points of the input signal is greater than the width threshold and the amplitude of the acquired signal is greater than the amplitude threshold, it is considered that the input signal is a pulse echo signal, and the pulse detector 13 inputs the pulse echo signal to the pulse interval matching module 14. The pulse interval matching module 14 Receive a periodic pulse signal and a chaotic pulse signal, and calculate the time interval between the periodic pulse signal and the chaotic pulse signal. The pulse interval matching module 14 also receives the pulse echo signal detected by the pulse detector 13. When the time interval between the two pulse echo signals is the same as the time interval between the periodic pulse signal and the chaotic pulse signal, it is considered that the signal is successfully matched. The signal matching subunit inputs the two successfully matched pulse echo signals to the signal processing unit 15 for processing. The signal processing unit 15 calculates the emission time and the echo time of the periodic pulse signal to obtain a first delay time, and then calculates the emission time and the echo time of the chaotic pulse signal to obtain a second delay time. The signal processing unit 15 calculates the average delay time based on the first delay time and the second delay time to obtain a final time delay, and then calculates the target distance based on the time delay. The signal processing unit 15 sends the target distance to the display unit 16 in real time for display.

[0030] The clock control unit 17 is respectively connected to the pulse signal generating module, the chaotic pulse signal generating module, N signal matching subunits and N transmitting and receiving subunits; the clock control unit 17 is connected to the pulse signal generating module and the chaotic pulse signal generating module, on the one hand, for providing a clock, and on the other hand, for ensuring that the pulse signal generating module and the chaotic pulse signal generating module transmit signals simultaneously; the clock control unit 17 is connected to the N transmitting and receiving subunits, for ensuring that the signal acquisition subunits 12 in the N transmitting and receiving subunits achieve simultaneous sampling; the clock control unit 17 is connected to the N signal matching subunits, for providing a clock for each pulse detector 13, and ensuring that the N signal matching subunits work simultaneously.

[0031] Preferably, the pulse signal generating module includes a first pulse signal generator 18 and a first N-way power divider 19, the first pulse signal generator 18 is used to generate a periodic pulse signal, and generates N-way periodic pulse signals through the first N-way power divider 19; the chaotic pulse signal generating module includes a chaotic mapping module 20, a counter 21, a comparator 22, a second pulse signal generator 23, a second N-way power divider 24 and N electrical delay lines, the chaotic mapping module 20 is used to generate a random number in the range of [0,1], the counter 21 starts counting from zero, the output end of the chaotic mapping module 20 and the output end of the counter 21 are both connected to the input end of the comparator 22, and the output end of the comparator 22 is connected to the second pulse signal generator 2 3, the second pulse signal generator 23 is connected to the second N-way power divider 24, and N-way chaotic pulse signals are generated by the second N-way power divider 24, and the N-way chaotic pulse signals are output after passing through N electrical delay lines respectively; the output of the chaotic mapping module 20 and the output of the counter 21 are input to the comparator 22 for comparison, and when the output of the counter 21 is greater than the output of the chaotic mapping module 20, the second pulse signal generator 23 is triggered to generate a new chaotic pulse signal, and the new chaotic pulse signal is closed-loop fed back to the counter 21 and the input end of the chaotic mapping module 20, and the rising edge triggers the reset counter 21 to zero, and updates the output of the chaotic mapping module 20 to enter the next state; the chaotic mapping module 20 adopts a composite chaotic mapping. In a specific embodiment, the chaotic mapping module 20 adopts a hybrid of an improved Logistic mapping and a type I third-order Chebychev polynomial to generate a composite chaotic mapping.

[0032] The calculation formula of the improved Logistic mapping is:

[0033] ;

[0034] The third-order Chebychev polynomial of type I is:

[0035] Then the formula of the composite chaotic mapping is: .

[0036] The intervals of each periodic pulse signal and each chaotic pulse signal vary randomly within each pulse repetition period. After the periodic pulse signal is up-converted by the first mixer 3 and amplified by the first power amplifier 6, it transmits the signal to the ground through the first transmitting antenna 8; after the chaotic pulse signal is up-converted by the second mixer 4 and amplified by the second power amplifier 7, it transmits the signal to the ground through the second transmitting antenna 9; when the transmission signals of the first transmitting antenna 8 and the second transmitting antenna 9 to the ground encounter different underground medium interfaces, they are reflected to form echo signals, and the echo signals are down-converted by the receiving antenna 10, the low noise amplifier 11, and the mixer, and then enter the signal acquisition subunit 12 for acquisition. After the N channels are sampled in parallel, the data is input into the N signal matching subunits for pulse detection and pulse interval matching. The N signal matching subunits are processed in parallel. If the matching is successful, the pulse echo signal enters the signal processing unit 15 for processing, and finally displayed in real time on the display unit. Through the signal matching subunit, the signal interference of other channels and the electromagnetic interference in the environment are eliminated, so that each channel can work simultaneously without time division multiplexing. The clock control unit 17 generates a reference clock for controlling the clocks of the signal generating unit, the signal acquisition unit and the signal matching unit. The signal generating unit, the signal matching unit, the signal processing unit 15 and the clock control unit 17 are all implemented on the FPGA. In the chaotic pulse signal generating module, since the cross-correlation between the delayed chaotic pulse signal and the undelayed chaotic pulse signal is small, the N chaotic pulse signals generated are orthogonal to each other. The trigger clocks of the first pulse signal generator 18 and the second pulse signal generator 23 are synchronized, and the intervals between the periodic pulse signal and the chaotic pulse signal vary randomly within each pulse repetition period. The N transmitting and receiving subunits can change the center frequency of the transmitting signal by adjusting the local oscillator frequency of the local oscillator signal generator 1.

[0037] On the basis of the above embodiments, in a preferred embodiment, the pulse repetition period of the first pulse signal generator 18 and the second pulse signal generator 23 is the same, and the maximum delay time of the electric delay line is less than the pulse repetition period; within the pulse repetition period of the first pulse signal generator 18 and the second pulse signal generator 23, the intervals between the periodic pulse signal and the chaotic pulse signal change randomly.

[0038] Based on the above embodiments, in a preferred embodiment, the first transmitting antenna 8, the second transmitting antenna 9 and the receiving antenna 10 are shielded air-coupled planar antennas, and the center frequencies of the first transmitting antenna 8, the second transmitting antenna 9 and the receiving antenna 10 are consistent with the center frequencies of the periodic pulse signal, the chaotic pulse signal and the local oscillator frequency of the local oscillator signal generator 1.

[0039] On the basis of the above embodiments, in a preferred embodiment, the shielded air-coupled planar antenna is a planar butterfly antenna, a planar Vivaldi antenna or a planar helical antenna.

[0040] On the basis of the above embodiments, in a preferred embodiment, the local oscillation frequency of the local oscillation signal generator 1 is 160 MHz, 270 MHz, 400 MHz, 600 MHz or 900 MHz.

[0041] Based on the above embodiment, in a preferred embodiment, the total length of the first transmitting antenna 8, the second transmitting antenna 9 and the receiving antenna 10 in the N transmitting and receiving subunits is less than or equal to 2 m. All antenna arrays of the N transmitting and receiving subunits basically cover the entire road surface and do not hinder the driving of vehicles in the adjacent lanes.

[0042] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A multi-channel chaotic ground penetrating radar device for urban road disease detection, characterized in that: It comprises a signal generating unit, a transmitting and receiving unit, a signal matching unit, a signal processing unit (15), a clock control unit (17) and a display unit (16); The signal generating unit includes a pulse signal generating module for generating N-channel periodic pulse signals and a chaotic pulse signal generating module for generating N-channel chaotic pulse signals; The transmitting and receiving unit comprises N transmitting and receiving subunits, each of which comprises a local oscillator signal generator (1), a three-way power divider (2), a first mixer (3), a second mixer (4), a third mixer (5), a first power amplifier (6), a second power amplifier (7), a first transmitting antenna (8), a second transmitting antenna (9), a receiving antenna (10), a low noise amplifier (11) and a signal acquisition subunit (12); the local oscillator signal generator (1) generates three local oscillator signals through the three-way power divider (2), the three local oscillator signals are respectively connected to the first mixer (3), the second mixer (4) and the third mixer (5), and the output end of the first mixer (3) is connected to the output end of the first mixer (3) through the first power amplifier (6). connected to the input end of the first transmitting antenna (8); the output end of the second mixer (4) is connected to the input end of the second transmitting antenna (9) through the second power amplifier (7); the output end of the receiving antenna (10) is connected to the input end of the third mixer (5) through the low noise amplifier (11); N-channel periodic pulse signals are respectively connected to the first mixers (3) of the N transmitting and receiving subunits, and N-channel chaotic pulse signals are respectively connected to the second mixers (4) of the N transmitting and receiving subunits; the first transmitting antenna (8) and the second transmitting antenna (9) are used to transmit electromagnetic waves to the ground, and the receiving antenna (10) is used to receive echo signals; the output end of the third mixer (5) is used to collect signals through the signal collection subunit (12); The signal matching unit comprises N signal matching subunits, each signal matching subunit comprises a pulse detector (13) and a pulse interval matching module (14), the output end of the pulse detector (13) is connected to the input end of the pulse interval matching module (14), N-channel periodic pulse signals are respectively connected to the pulse detectors (13) and the pulse interval matching modules (14) of the N signal matching subunits, N-channel chaotic pulse signals are respectively connected to the pulse detectors (13) and the pulse interval matching modules (14) of the N signal matching subunits, the output ends of the N signal acquisition subunits (12) are connected to the pulse detectors (13) of the N signal matching subunits, the pulse detector (13) is provided with an amplitude threshold and a width threshold, when the number of sampling points of the input signal is greater than the width threshold and the amplitude of the acquired signal is greater than the amplitude threshold, the input signal is considered to be a pulse echo signal, and the pulse detector (13) inputs the pulse echo signal to the pulse interval matching module (14); the pulse interval matching module (14) is connected to the pulse detector (13) of the N signal matching subunits, and the pulse detector (13) is connected to the pulse detector (13) of the N signal matching subunits. The matching module (14) receives the periodic pulse signal and the chaotic pulse signal, and calculates the time interval between the periodic pulse signal and the chaotic pulse signal. The pulse interval matching module (14) also receives the pulse echo signal detected by the pulse detector (13). When the time interval between the two pulse echo signals is the same as the time interval between the periodic pulse signal and the chaotic pulse signal, it is considered that the signal matching is successful. The signal matching subunit inputs the two successfully matched pulse echo signals to the signal processing unit (15) for processing. The signal processing unit (15) calculates the emission time and the echo time of the periodic pulse signal to obtain a first delay time, and then calculates the emission time and the echo time of the chaotic pulse signal to obtain a second delay time. The signal processing unit (15) calculates the average delay time based on the first delay time and the second delay time to obtain a final time delay, and then calculates the target distance based on the time delay. The signal processing unit (15) sends the target distance to the display unit (16) in real time for display. The clock control unit (17) is respectively connected to the pulse signal generating module, the chaotic pulse signal generating module, the N signal matching subunits and the N transmitting and receiving subunits; the clock control unit (17) is connected to the pulse signal generating module and the chaotic pulse signal generating module, and is used to provide a clock on the one hand, and to ensure that the pulse signal generating module and the chaotic pulse signal generating module transmit signals at the same time on the other hand; the clock control unit (17) is connected to the N transmitting and receiving subunits, and is used to ensure that the signal acquisition subunits (12) in the N transmitting and receiving subunits achieve simultaneous sampling; the clock control unit (17) is connected to the N signal matching subunits, and is used to provide a clock for each pulse detector (13), and ensure that the N signal matching subunits work at the same time.

2. The multi-channel chaotic ground penetrating radar device for urban road disease detection according to claim 1 is characterized in that: The pulse signal generating module comprises a first pulse signal generator (18) and a first N-way power divider (19), wherein the first pulse signal generator (18) is used to generate a periodic pulse signal and generate N-way periodic pulse signals through the first N-way power divider (19); the chaotic pulse signal generating module comprises a chaotic mapping module (20), a counter (21), a comparator (22), a second pulse signal generator (23), a second N-way power divider (24) and N electrical delay lines, wherein the chaotic mapping module (20) is used to generate [0 ,1], the counter (21) starts counting from zero, the output end of the chaotic mapping module (20) and the output end of the counter (21) are both connected to the input end of the comparator (22), the output end of the comparator (22) is connected to the input end of the second pulse signal generator (23), the second pulse signal generator (23) is connected to the second N-way power divider (24), and N-way chaotic pulse signals are generated through the second N-way power divider (24), and the N-way chaotic pulse signals are output after passing through N electrical delay lines respectively; The output of the chaotic mapping module (20) and the output of the counter (21) are input to a comparator (22) for comparison. When the output of the counter (21) is greater than the output of the chaotic mapping module (20), the second pulse signal generator (23) is triggered to generate a new chaotic pulse signal. The new chaotic pulse signal is closed-loop fed back to the counter (21) and the input end of the chaotic mapping module (20). The rising edge triggers the reset of the counter (21) to zero, and updates the output of the chaotic mapping module (20) to enter the next state. The chaotic mapping module (20) uses an improved Logistic mapping and a type I third-order Chebychev polynomial to generate a composite chaotic map. The calculation formula of the improved Logistic mapping is: ； The third-order Chebychev polynomial of type I is: Then the calculation formula of the composite chaotic map is: .

3. The multi-channel chaotic ground penetrating radar device for urban road disease detection according to claim 2 is characterized in that: The pulse repetition periods of the first pulse signal generator (18) and the second pulse signal generator (23) are the same, and the maximum delay time of the electric delay line is less than the pulse repetition period; within the pulse repetition period of the first pulse signal generator (18) and the second pulse signal generator (23), the intervals between the periodic pulse signal and the chaotic pulse signal vary randomly.

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