Dual-polarization array type multi-frequency microwave band electromagnetic detection equipment and method

Abstract

The invention discloses a dual-polarization array type multi-frequency microwave band electromagnetic detection device and method, the device comprises a high-directionality dual-polarization transmitting antenna and more than two high-directionality dual-polarization receiving antennas, the high-directionality dual-polarization transmitting antenna is electrically connected with a microwave broadband transmitting system, and the microwave broadband transmitting system is electrically connected with the high-directionality dual-polarization receiving antennas. And each high-directionality dual-polarization receiving antenna is electrically connected with one broadband superheterodyne receiving circuit system. The detection equipment disclosed by the invention adopts high-directionality, dual-polarization (horizontal and vertical) and array antennas, realizes acquisition of scattering multi-component microwave electromagnetic signals, effectively improves the detection capability of weak scattering signals, breaks through the limitation that the detection depth of a traditional geological prospecting instrument on an underground target is relatively small, and improves the detection precision of the underground target. And high-resolution detection of an underground deeper complex space target body can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of geological exploration, and in particular relates to a dual-polarization array multi-frequency microwave band electromagnetic detection equipment and method in this field, which measures underground complex space targets based on the basic principle of electromagnetic reflection and has high sensitivity. Background Art

[0002] In recent years, the development and utilization of urban underground space has increased, and with the rapid development of trenchless technology, the technical difficulties of underground construction in complex areas such as buildings, streets, rivers, and railways in cities no longer exist. Due to the unclear information on the existence of underground space targets (gas pipelines, water supply, power supply pipelines, etc.), gas pipelines, water supply, and power supply pipelines are frequently broken and damaged during trenchless construction. In order to avoid damage to the front target during trenchless construction excavation, it is necessary to accurately detect urban underground targets (gas pipelines, water supply, power supply pipelines, etc.).

[0003] At present, the commonly used detection methods for urban underground targets (gas pipelines, water supply, power supply pipelines, etc.) at home and abroad include gyroscope inertial positioning method, tracer detection method, active acoustic wave method, ground penetrating radar method, DC resistivity method, etc. The gyroscope inertial positioning method has a large detection depth and high detection accuracy, and is suitable for pipelines of various materials, but it is necessary to open a window on the pipeline / pipeline in order to place the gyroscope in the pipeline, which will cause the pipeline / pipeline to stop operating. The principle of the tracer detection method is to send a metal wire or tracer probe that can excite electromagnetic waves into the pipeline, and the receiver located on the surface receives the electromagnetic signal. The advantage is that the detection depth is large and the detection accuracy is high. However, since metal will shield the propagation of electromagnetic waves, the tracer detection method is not suitable for metal pipelines. The active acoustic wave method also requires that the pipeline has a sound source access port. Ground penetrating radar is often used for the detailed detection of underground targets. It is simple to construct, low in cost, high in efficiency, high in resolution and capable of imaging. However, ground penetrating radar uses high-frequency pulse waves for detection, and high-frequency electromagnetic waves have large attenuation. At the same time, the directivity of ground penetrating radar antennas is relatively poor, which makes it impossible to detect and distinguish targets deep underground in cities. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect that traditional surface electromagnetic detection equipment and methods cannot perform non-destructive, high-precision and deep detection of urban underground targets (non-metallic pipelines such as gas pipelines, water supply and power supply pipelines), and to provide a dual-polarization array multi-frequency microwave band electromagnetic detection equipment and method with a detection resolution accuracy of millimeter level and a non-destructive detection depth of tens of meters.

[0005] The present invention adopts the following technical solution: A dual-polarization array multi-frequency microwave electromagnetic detection equipment, the improvement of which is that it comprises a highly directional dual-polarization transmitting antenna and more than two highly directional dual-polarization receiving antennas, the highly directional dual-polarization transmitting antenna is electrically connected to a microwave broadband transmitting system, each highly directional dual-polarization receiving antenna is electrically connected to a broadband superheterodyne receiving circuit system, the broadband superheterodyne receiving circuit system comprises a pre-low noise amplifier, a mixer, an emitter follower amplifier, a narrowband filter, a low noise variable gain amplifier and a driving amplifier which are electrically connected together in sequence, the mixers of each broadband superheterodyne receiving circuit system are electrically connected to a microwave broadband local oscillator system, the driving amplifiers are electrically connected to a multi-channel synchronous analog-to-digital conversion circuit, the multi-channel synchronous analog-to-digital conversion circuit is electrically connected to a digital signal processing circuit, and a high-precision clock synchronization circuit is electrically connected to the above-mentioned microwave broadband transmitting system, microwave broadband local oscillator system and digital signal processing circuit respectively.

[0006] Furthermore, the microwave broadband transmission system includes a frequency agile microwave signal generator, a digital programmable adjustable resonant frequency filter and a high-gain high-power amplifier.

[0007] Furthermore, the microwave broadband local oscillator system includes a frequency agile microwave signal generator, a digital programmable adjustable resonant frequency filter and a high-gain high-power driver.

[0008] Furthermore, the multi-channel synchronous analog-to-digital conversion circuit includes a high-temperature rail-to-rail operational amplifier, a high-precision reference power supply and a multi-channel high-precision synchronous acquisition analog-to-digital converter.

[0009] Furthermore, the digital signal processing circuit includes a high-speed signal processing main controller, a high-precision reference voltage device, a high-speed crystal oscillator and a large-capacity memory.

[0010] A dual-polarization array multi-frequency microwave band electromagnetic detection method uses the above equipment, and its improvement lies in that: after a microwave broadband transmitting system generates a broadband microwave signal, it is transmitted underground by a highly directional dual-polarization transmitting antenna, and the scattered signal caused by the underground abnormal body is received by the highly directional dual-polarization receiving antenna after propagating through the stratum, and is amplified in sequence by a pre-low noise amplifier of a broadband superheterodyne receiving circuit system, mixed by a mixer with lower side frequencies, amplified by an emitter follower amplifier, filtered by a narrowband filter, amplified by a low-noise variable gain amplifier and a driving amplifier, and then sent to a multi-channel synchronous analog-to-digital conversion circuit to be converted into a digital signal, and finally processed and stored by a digital signal processing circuit, a microwave broadband local oscillator system provides a broadband microwave local oscillator signal for the mixer of the broadband superheterodyne receiving circuit system, and a high-precision clock synchronization circuit realizes clock synchronization among the microwave broadband transmitting system, the microwave broadband local oscillator system and the digital signal processing circuit.

[0011] Furthermore, the frequency range of the broadband microwave signal and the broadband microwave local oscillator signal is 1 to 10 GHz.

[0012] The beneficial effects of the present invention are: The detection equipment disclosed in the present invention adopts highly directional, dual-polarized (horizontal, vertical), arrayed antennas to collect scattered multi-component microwave electromagnetic signals, effectively improve the detection capability of weak scattered signals, break through the limitation of shallow detection depth of underground targets by traditional geological exploration instruments, and realize high-resolution detection of complex space targets deep underground. Different antenna array combinations can meet the needs of different detection scenarios and realize non-destructive, high-precision, high-resolution interface detection of urban underground space targets (gas pipelines, water supply, power supply pipelines and other non-metallic pipelines).

[0013] The detection equipment disclosed in the present invention utilizes the higher resolution capability of time-harmonic, multi-frequency microwave signals, eliminates the influence of background interference signals through strong directional signal transmission, weak signal detection, strong interference suppression, and collection of multi-component electromagnetic field information of scattered echoes; and greatly improves the non-destructive, non-contact, and deep-depth detection capability of underground non-metallic pipelines.

[0014] The detection method disclosed in the present invention uses highly directional, arrayed microwave electromagnetic detection and identification technology to achieve rapid positioning and inversion of urban underground non-metallic pipelines, greatly improving the imaging resolution capability. It uses 1-10GHz broadband microwave signals with multiple operating frequencies to perform scanning detection on the interfaces of urban underground space targets (gas pipelines, water supply, power supply network and other non-metallic pipelines) at different depths. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a block diagram of the composition of the detection equipment disclosed in the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Embodiment 1, this embodiment discloses a dual-polarization array multi-frequency microwave band electromagnetic detection equipment, using the multi-frequency microwave band signal generated by the transmitting antenna. The microwave signal encounters an abnormal body during underground propagation. Due to the difference in electrical parameters between the abnormal body and the surrounding strata, scattering occurs. The scattered signal has a certain relationship with the size, position, and electrical parameters of the abnormal body. The scattered echo information is measured by an arrayed, directional antenna to interpret and image the geometric and electrical parameters of the abnormal body in the stratum.

[0018] like Figure 1 As shown, it includes a highly directional dual-polarization (vertical, horizontal) transmitting antenna and more than two highly directional dual-polarization (vertical, horizontal) receiving antennas. Highly directional microwave antennas are used to assemble multiple horizontally and vertically polarized electric field and magnetic field transmitting and receiving antenna arrays, which can realize the transmission and collection of scattered multi-component electromagnetic wave signals at different depths and eliminate the influence of direct-coupled signals; at the same time, an antenna array composed of multiple antennas with different transmitting-receiving spacings and multiple microwave (1GHz~10GHz) working frequencies is used to accurately detect multi-component microwave scattering signals of urban underground targets (gas pipelines, water supply, power supply pipelines and other non-metallic pipelines).

[0019] The highly directional dual-polarized transmitting antenna is electrically connected to a microwave broadband transmitting system, each highly directional dual-polarized receiving antenna is electrically connected to a broadband superheterodyne receiving circuit system, the broadband superheterodyne receiving circuit system comprises a pre-low noise amplifier, a mixer, an emitter follower amplifier, a narrowband filter, a low noise variable gain amplifier and a driving amplifier which are electrically connected in sequence, the mixers of each broadband superheterodyne receiving circuit system are electrically connected to a microwave broadband local oscillator system, the driving amplifiers are electrically connected to a multi-channel synchronous analog-to-digital conversion circuit, the multi-channel synchronous analog-to-digital conversion circuit is electrically connected to a digital signal processing circuit, and the high-precision clock synchronization circuit is electrically connected to the above-mentioned microwave broadband transmitting system, the microwave broadband local oscillator system and the digital signal processing circuit respectively.

[0020] In this embodiment, the microwave broadband transmission system includes a frequency agile microwave signal generator, a digital programmable adjustable resonant frequency filter and a high-gain high-power amplifier.

[0021] The microwave broadband local oscillator system comprises a frequency agile microwave signal generator, a digital program-controlled adjustable resonant frequency filter and a high-gain high-power driver.

[0022] The multi-channel synchronous analog-to-digital conversion circuit is a multi-channel high-precision analog-to-digital conversion circuit, including a high-temperature rail-to-rail operational amplifier, a high-precision reference power supply and a multi-channel high-precision synchronous acquisition analog-to-digital converter.

[0023] The digital signal processing circuit includes a high-speed signal processing main controller, a high-precision reference voltage device, a high-speed crystal oscillator and a large-capacity memory.

[0024] This embodiment also discloses a dual-polarization array multi-frequency microwave band high-sensitivity electromagnetic detection method. Using the above-mentioned equipment, after the microwave broadband transmission system generates a broadband microwave signal, it is transmitted underground by a highly directional dual-polarization transmission antenna. The scattered signal caused by the underground abnormal body is propagated through the stratum and received by the highly directional dual-polarization receiving antenna. It is amplified in sequence by the pre-low noise amplifier of the broadband superheterodyne receiving circuit system, mixed by the lower side frequency of the mixer, amplified by the emitter follower amplifier, filtered by a narrowband filter, amplified by a low-noise variable gain amplifier and a driving amplifier, and processed by down-conversion. The circuit is then sent to a multi-channel synchronous analog-to-digital conversion circuit, which converts the multi-channel scattered echo electromagnetic analog signals into digital signals. Finally, the digital signal processing circuit performs data processing and storage. The microwave broadband local oscillator system provides a broadband microwave local oscillator signal for the mixer of the broadband superheterodyne receiving circuit system. The high-precision clock synchronization circuit realizes clock synchronization between the microwave broadband transmission system, the microwave broadband local oscillator system (receiving system) and the digital signal processing circuit.

[0025] The frequency range of broadband microwave signals and broadband microwave local oscillator signals is 1 to 10 GHz. The microwave multi-frequency transmitting antenna transmits multiple time-harmonic microwave band working electromagnetic signals in the range of 1 to 10 GHz to the stratum. The transmitting signal excites the microwave frequency band and time-harmonic field (primary field) through the dual-polarization (horizontal and vertical) transmitting antenna. Due to the difference in density between the underground target body and the surrounding interface, the deep underground abnormal body and the surrounding stratum interface cause microwave electromagnetic signal scattering. The scattered signal (multi-component electromagnetic echo signal) propagates through the stratum and is received by the array receiving antenna in the dual-polarization direction (horizontal and vertical), thereby completing the reception of multi-component microwave signals scattered by multiple urban underground target bodies (gas pipelines, water supply, power supply pipelines and other non-metallic pipelines).

Claims

1. A dual-polarization array multi-frequency microwave band electromagnetic detection equipment, characterized in that: The invention comprises a highly directional dual-polarized transmitting antenna and more than two highly directional dual-polarized receiving antennas. The highly directional dual-polarized transmitting antenna is electrically connected to a microwave broadband transmitting system. Each highly directional dual-polarized receiving antenna is electrically connected to a broadband superheterodyne receiving circuit system. The broadband superheterodyne receiving circuit system comprises a pre-low noise amplifier, a mixer, an emitter follower amplifier, a narrowband filter, a low noise variable gain amplifier and a driving amplifier which are electrically connected in sequence. The mixers of each broadband superheterodyne receiving circuit system are electrically connected to a microwave broadband local oscillator system. The driving amplifiers are electrically connected to a multi-channel synchronous analog-to-digital conversion circuit. The multi-channel synchronous analog-to-digital conversion circuit is electrically connected to a digital signal processing circuit. A high-precision clock synchronization circuit is electrically connected to the above-mentioned microwave broadband transmitting system, the microwave broadband local oscillator system and the digital signal processing circuit respectively.

2. The dual-polarization array multi-frequency microwave band electromagnetic detection equipment according to claim 1, characterized in that: The microwave broadband transmission system comprises a frequency agile microwave signal generator, a digital program-controlled adjustable resonant frequency filter and a high-gain high-power amplifier.

3. The dual-polarization array multi-frequency microwave band electromagnetic detection equipment according to claim 1, characterized in that: The microwave broadband local oscillator system comprises a frequency agile microwave signal generator, a digital program-controlled adjustable resonant frequency filter and a high-gain high-power driver.

4. The dual-polarization array multi-frequency microwave band electromagnetic detection equipment according to claim 1, characterized in that: The multi-channel synchronous analog-to-digital conversion circuit comprises a high-temperature rail-to-rail operational amplifier, a high-precision reference power supply and a multi-channel high-precision synchronous acquisition analog-to-digital converter.

5. The dual-polarization array multi-frequency microwave band electromagnetic detection equipment according to claim 1, characterized in that: The digital signal processing circuit includes a high-speed signal processing main controller, a high-precision reference voltage device, a high-speed crystal oscillator and a large-capacity memory.

6. A dual-polarization array multi-frequency microwave band electromagnetic detection method, using the equipment described in claim 1, characterized in that: After the broadband microwave transmission system generates broadband microwave signals, they are transmitted underground by a highly directional dual-polarization transmitting antenna. The scattered signals caused by underground anomalies propagate through the stratum and are received by a highly directional dual-polarization receiving antenna. They are amplified in sequence by a pre-low-noise amplifier of a broadband superheterodyne receiving circuit system, mixed by a mixer with lower sidebands, amplified by an emitter follower amplifier, filtered by a narrowband filter, amplified by a low-noise variable gain amplifier and a driver amplifier, and then sent to a multi-channel synchronous analog-to-digital conversion circuit to be converted into a digital signal. Finally, the digital signal processing circuit processes and stores the data. The broadband microwave local oscillator system provides a broadband microwave local oscillator signal for the mixer of the broadband superheterodyne receiving circuit system. The high-precision clock synchronization circuit realizes clock synchronization among the broadband microwave transmission system, the broadband microwave local oscillator system and the digital signal processing circuit.

7. The dual-polarization array multi-frequency microwave band electromagnetic detection method according to claim 6, characterized in that: The frequency range of the broadband microwave signal and the broadband microwave local oscillator signal is 1 to 10 GHz.

Images