CN113219460A - Multi-transmitting and multi-receiving imaging radar for slope monitoring - Google Patents

Abstract

The invention discloses a multi-shot multi-receive imaging radar for slope monitoring, which is characterized by comprising M transmitting array antennas and N micro-strip array antennas for receiving array antennas, a frequency modulation continuous wave radar radio frequency front end module, an ADC module, a data storage module, a data conversion module, a radar signal processing module and an external data interaction interface module, wherein the micro-strip array antennas receive electromagnetic wave signals reflected by a slope, the electromagnetic wave signals are processed by the frequency modulation continuous wave radar radio frequency front end module to output intermediate frequency signals, the radar signal processing module receives the intermediate frequency signals converted and output by the ADC module, digital signal processing is carried out on the intermediate frequency signals to complete slope imaging, and the slope imaging and the reference slope radar imaging stored by the data storage module are subjected to image comparison to judge whether the slope is deformed; and the external data interaction interface module outputs the slope image monitoring result to the outside. The invention has the advantages of small volume, convenient installation and maintenance, high image acquisition speed and low cost.

Description

Multi-transmitting and multi-receiving imaging radar for slope monitoring

Technical Field

The invention relates to the technical field of geological disaster monitoring radars, in particular to a multi-transmitting and multi-receiving imaging radar for side slope monitoring.

Background

The side slope is mainly divided into a building side slope, a municipal side slope, a mountain retaining wall and the like. Aiming at the sections with larger harmfulness, automatic equipment needs to be adopted for real-time online monitoring. The slope monitoring provides a technical basis for preventing and treating landslide and possible sliding, creeping deformation collapse and collapse, and the development trend of displacement and deformation of the slope in future is predicted and forecasted. The monitoring can be used for carrying out related research on the aging characteristics of the rock-soil body. By monitoring the deformation characteristics and rules of collapse and landslide, the boundary conditions, scale, sliding direction, occurrence time and harmfulness of the landslide body can be predicted and forecasted, and disaster prevention measures can be taken in time to avoid and reduce the disaster loss of engineering and personnel as much as possible. The monitoring can provide corresponding parameter basis for decision departments and relevant information for relevant aspects so as to make corresponding disaster prevention and relief countermeasures.

At present, radars for monitoring side slopes mainly comprise transmitting and receiving ground-based synthetic aperture imaging radars, and the large aperture of an antenna of the radars is synthesized by mechanical motion of the antenna along a high-precision track. In order to realize high-precision deformation measurement, the antenna needs to keep the track highly stable when moving along the track, so the moving speed of the antenna cannot be too fast, the scanning period of the antenna is about several minutes, and the real-time performance of the radar is not high. In order to increase the acquisition speed of radar images, the length of the guide rail can be shortened, however, the length of the steel rail determines the upper limit of the synthetic aperture, and the short rail causes the reduction of the azimuth resolution of the radar. The radar has high cost, large volume, large power consumption, complex structure and inconvenient installation and maintenance. The user continuously puts forward new requirements on the slope monitoring radar along with the continuous improvement of the monitoring requirements: high measurement accuracy, all-weather monitoring, low power consumption, low cost, convenient construction and maintenance and the like. However, mature slope monitoring radar schemes in the market are few at present, the cost is high, the installation and maintenance are inconvenient due to large volume, all-weather monitoring cannot be achieved, and the method is difficult to adapt to complex slope monitoring application scenes.

Disclosure of Invention

The invention provides a multi-transmitting multi-receiving imaging radar for slope monitoring, which has the advantages of small volume, convenient installation and maintenance, high image acquisition speed and low cost and can realize all-weather monitoring.

The invention adopts the following technical scheme:

a multiple-shot multiple-receive imaging radar for slope monitoring, comprising:

the microstrip array antenna comprises M transmitting array antennas and N receiving array antennas, wherein the transmitting array antennas are used for transmitting electromagnetic waves, and the receiving array antennas are used for receiving the electromagnetic waves in the space, which are reflected back by the slope surface, of the transmitting electromagnetic waves;

the frequency modulation continuous wave radar radio frequency front end module comprises a plurality of radio frequency transceivers which are cascaded to form M transmitting channels and N receiving channels, wherein the M transmitting channels correspondingly and respectively transmit electromagnetic waves through the M transmitting array antennas, and the N receiving channels correspondingly and respectively receive the electromagnetic waves reflected by the slope surface through the N receiving array antennas; the reflected electromagnetic wave signals are subjected to frequency mixing processing, and intermediate frequency signals containing distance information and direction information are output;

the ADC module is used for converting the intermediate frequency signal into a digital signal;

the data storage module is used for storing the digital signals of the currently acquired side slope and reference side slope radar imaging result data;

the radar signal processing module is used for receiving the intermediate frequency signal output by the ADC module, performing digital signal processing on the intermediate frequency signal to finish slope imaging, and performing image comparison on the slope imaging and the reference slope radar imaging to judge whether the slope is deformed;

and the external data interaction interface module is used for receiving the result of the slope image comparison output by the radar signal processing module, outputting the slope image monitoring result to the outside and adjusting the radar related parameters.

As an improvement of the above scheme, one of the radio frequency transceivers is a master, the other radio frequency transceivers are slaves, a constant circuit and an external resonant circuit in the master generate a reference clock signal, the reference clock signal is output by a clock pin, one path of reference clock signal is divided into a plurality of paths through a clock buffer, and a synchronous clock reference signal is provided for the other paths of slaves, thereby realizing cascade connection.

Furthermore, the multi-shot multi-receive imaging radar for slope monitoring further comprises a data conversion module, wherein the data conversion module is used for converting the digital signals into a format defined by the radar signal processing module.

Preferably, the ADC module is connected to the data conversion module through a high-speed digital signal connector.

Preferably, the data conversion module includes several FPGAs of the same type, and each FFPA is responsible for converting ADC data output by one radio frequency transceiver; NOR Flash is connected with the outside of each FPGA to expand the storage capacity of the FPAG.

As an improvement of the scheme, the external data interaction interface module comprises a network port communication circuit and a USB2.0 interface-to-serial port circuit, the network port communication circuit is used for outputting the slope monitoring result, and the USB2.0 interface-to-serial port circuit is used for adjusting some parameters of the whole radar system by an upper computer on a computer.

As an improvement of the above scheme, the multiple-shot imaging radar for slope monitoring further comprises a power supply module, which is composed of a power supply protection circuit, a direct current voltage drop circuit, a linear voltage stabilizing circuit, a power supply filter and a power supply management chip circuit, wherein an output end of the power supply protection circuit is connected with an input end of the direct current voltage drop circuit, a first output end of the direct current voltage drop circuit is connected with an input end of the power supply management chip, and an output end of the power supply management chip is respectively connected with the frequency modulation continuous wave radar radio frequency front end module and the ADC module for supplying power; the second output end of the direct current voltage reduction circuit is connected with a plurality of linear voltage stabilizing circuits for voltage reduction and then respectively supplies power to the data conversion module and the external data interaction interface module; and the second output end of the direct current voltage reduction circuit is also connected with a power management chip circuit to carry out voltage reduction and then respectively supply power to the data storage module and the radar signal processing module.

Preferably, the multiple-shot imaging radar for slope monitoring further comprises a memory module which is composed of a plurality of memory chips and is connected with the radar signal processing module in a T-shaped topological structure mode.

Advantageous effects

The multiple-input multiple-output synthetic aperture imaging radar is used as a novel radar for high-precision and high-speed deformation measurement. Based on the MIMO technology, a large synthetic aperture can be obtained by using a plurality of transmitting and receiving antennas to form a specific structure. In the imaging period of the multiple-transmitting and multiple-receiving radar, the transmitting antennas can transmit signals at the same time or different times, and the receiving antennas can simultaneously receive echo signals. Therefore, the multi-shot imaging radar system can rapidly scan a monitoring scene, and compared with the single-shot synthetic aperture radar, the image acquisition interval can be shortened to a few seconds. The multi-transmitting and multi-receiving radar can carry out deformation measurement on a scene with high deformation rate. The antenna does not adopt a metal track to synthesize a large aperture, so that the problem of phase error caused by vibration of the antenna on the track or unstable height of the track is avoided, and the problems of high cost, large volume, high installation and debugging difficulty and high maintenance cost caused by a guide rail are also avoided.

Drawings

Fig. 1 is an overall schematic diagram of a multiple-shot multiple-receive imaging radar for slope monitoring according to the present embodiment;

fig. 2 is a schematic diagram of a microstrip array antenna of the multiple-transmit multiple-receive imaging radar provided in this embodiment;

fig. 3 is a directional diagram of a single microstrip array antenna of the multiple-transmission multiple-reception imaging radar provided by the embodiment;

fig. 4 is a schematic diagram of a power supply module of the multiple-transmit multiple-receive imaging radar provided in this embodiment;

fig. 5 is a schematic diagram of a memory module of the multiple-transmit-multiple-receive imaging radar provided in this embodiment;

fig. 6 is a schematic diagram of a single rf transceiver of the multiple-transmit-multiple-receive imaging radar provided in this embodiment;

fig. 7 is a schematic diagram of a radio frequency front end module of the multiple-transmit multiple-receive imaging radar according to the present embodiment;

fig. 8 is a schematic diagram of a data conversion module of the multiple-transmit multiple-receive imaging radar according to the present embodiment;

fig. 9 is a schematic diagram of a data storage module of the multiple-shot imaging radar provided in this embodiment;

fig. 10 is a schematic diagram of an external data interaction interface module of the multiple-transmit-multiple-receive imaging radar according to the present embodiment;

fig. 11 is a schematic diagram of a radar signal processing module of the multiple-transmit multiple-receive imaging radar according to the present embodiment;

fig. 12 is a schematic diagram of a radar signal processing flow of the multiple-shot imaging radar according to the embodiment.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Referring to fig. 1, the multiple-shot imaging radar for slope monitoring mainly comprises a microstrip array antenna module, a frequency modulation continuous wave radar radio frequency front end, an ADC module, a data conversion module, a memory module, a radar signal processing module, a data storage module, an external data interaction interface module, and a power supply module 9.

Referring to fig. 2 and 3, the microstrip array antenna module is composed of N reception array antennas RX and M transmission array antennas TX. Each individual antenna is made up of 4 elements, and the half-power beam width in the E-plane of each array antenna is 66 ° and the half-power beam width in the H-plane is 20 °. The antenna adopts the layout mode as shown in fig. 3, and the data processing is more convenient.

Referring to fig. 4, the power supply module is composed of a power protection circuit, a dc voltage reduction circuit, an LDO voltage regulator circuit (i.e., a linear voltage regulator circuit), a power filter, and a power management chip circuit. The system adopts 12V direct current voltage for power supply, and the loading capacity of the power supply can not be less than 3A. After entering the radar through the wiring terminal, the power supply firstly passes through the protection circuit, and then the power supply is converted into 5V voltage of 2 paths through the voltage reduction of the direct current voltage reduction circuit. One path of 5V voltage is converted into 3.3V by the LDO circuit and is converted into 1.8V, 1.2V and 1V by the power management chip circuit, and the voltages supply power for the frequency modulation continuous wave radar radio frequency front end and the ADC module after passing through the filter. And the other path of 5V voltage is subjected to voltage reduction and conversion by a plurality of LDO voltage stabilizing circuits and power management circuits to form 3.3V, 2.5V, 1.8V, 1.2V and 1.1V, and power is supplied to the data conversion module, the memory module, the radar data processing module, the data storage module and the external data interaction interface module.

Referring to fig. 5, the memory module is used to store temporary data required and generated in data calculation, in this embodiment, a DDR3, 40GB memory is used, 5 memory chips are used together, the capacity of a single memory chip is 8GB, the bus width of the memory chip is 16bit, the structure is 512Mx16, the clock frequency is 800MHz, and a "T" type topology structure is used between the 5 memory chips and the radar signal processing module.

Referring to fig. 6, an integrated rf transceiver is used in this implementation, with 3 transmit channels TX per rf transceiver, 13dBm transmit power per transmit channel, 4 receive channels RX, 12dB noise figure, and 4 12-bit ADC sampling channels integrated, with a maximum sampling rate of 37.5 Msps. As shown in fig. 7, in the transmission chain, a part of the 20GHz chirp signal is directly output to provide synchronous FMCW _ CLK for the cascade of multiple rf transceivers; the other part of the frequency-modulated continuous wave signals is frequency-multiplied by 4 to be 80GHz, and after the phase of the frequency-modulated continuous wave signals is shifted by the phase shifter phaser, one part of the frequency-modulated continuous wave signals is used as local oscillator signals for frequency mixing of a receiving link; the other signal enters a power amplifier PA, a frequency modulation continuous wave signal of 80GHz enters the microstrip array antenna from the starting port after being amplified, the guided wave is converted into electromagnetic wave in space, and then the electromagnetic wave signal is emitted. In a receiving link, electromagnetic waves reflected by a target in space are received by a receiving antenna and then converted into guided waves in a circuit, the guided waves enter a low noise amplifier (LAN) from a receiving port, signals enter a Mixer after being amplified and are mixed with local oscillator signals, an analog intermediate frequency signal (IF) is generated after mixing, and the analog IF signal is converted into a digital intermediate frequency (IF') after being sampled by an ADC (analog to digital converter) sampling module.

Referring to fig. 7, 4 rf transceivers are cascaded to form a fm continuous wave radar rf front end having M transmit channels and N receive channels. According to the theory of multiple-transmit-multiple-receive radar, the radar front end is equivalent to possessing MxN equivalent observation channels. In the fm continuous wave radar rf front end module of this embodiment, one rf transceiver is used as a master, and the other three are slaves. The master machine provides 2 paths of 20GHz frequency modulation signals FMCW _ CLK for the slave machines, the FMCW _ CLK is divided into 4 paths through the two Wilkinson power dividers, and the master machine and the 3 slave machines are provided with synchronous 20GHz frequency modulation signals FMCW _ CLK. The host machine generates a 40MHz reference clock signal by depending on an internal clock circuit and an external resonance circuit, the clock signal is output by a clock pin, one path of clock signal is divided into 3 paths by a clock buffer, and a synchronous clock reference signal is provided for 3 slave machines, so that cascade connection is realized. And the intermediate frequency digital signal IF' data after ADC sampling is output in a CSI2.0 communication format, and the signal is physically connected with the data conversion module through a high-speed digital signal connector. The configuration of the radio frequency related parameters is written into the digital front end of the radio frequency transceiver. The state output of a digital front end in a radio frequency transceiver, programming of a program and parameter configuration are realized by the methods of GPIO, Uart and SPI.

Referring to fig. 8, the data conversion module converts the format of the digital intermediate frequency signal IF' sampled by the ADC, and converts the data in the CSI2.0 communication format into a data format that can be recognized by a dedicated digital processing chip in the radar signal processing module. The module mainly comprises 4 FPGAs with the same model, and each FFPA is responsible for converting ADC data output by one radio frequency transceiver. The NOR Flash is carried outside each FPGA for expanding the storage capacity of the FPAG, and the FPGA program downloading interface is used for programming the FPGA program and debugging the FPGA.

Referring to fig. 9, the data storage module is used to store the raw ADC data and the final radar slope monitoring result. The connector adopted between the radar data processing module and the radar data processing module is also a standard PCIE2.0 protocol, namely a conventional PCIE2.0 connector communication protocol. The Flash memory mainly comprises a storage control circuit and a Flash circuit. The memory space of the memory module used in this embodiment is 512GB in total.

Referring to fig. 10, the external data interaction interface module is responsible for data interaction between the radar and other devices. The module mainly comprises a network port communication circuit and a USB2.0 interface-to-serial port circuit. The network port communication circuit is mainly responsible for outputting the slope monitoring result; the USB2.0 interface-serial port circuit is mainly responsible for adjusting some parameters of the whole radar system by an upper computer on a computer.

Referring to fig. 11, the radar signal processing module finally outputs the result data of slope monitoring through logic control of the whole radar module, radar data processing, imaging algorithm implementation and image comparison algorithm implementation. The module consists of a special digital signal processing chip circuit, an SD card seat and an ESD protection circuit thereof, a NORFlash circuit, a program downloading debugging interface circuit and a dial switch circuit. The special digital signal processing chip circuit is the core of the module, and the SD card seat circuit is used for updating relevant firmware programs in the radar system. The NOR Flash (1GB) circuit is used to expand the memory space of a dedicated digital signal processing chip, and performs data communication using QSPI. The program downloads the debugging interface circuit for debugging and downloading the code of the special digital signal processing chip, and the dial switch is used for selecting the BOOT mode.

Referring to fig. 12, it can be seen that the digital signal sampled by the ADC enters the chip dedicated for digital signal processing after format conversion, and then the processing steps are as follows: performing phase compensation on the signal; performing FFT transformation on the distance; performing FFT transformation of the azimuth direction; performing azimuth compression to improve image resolution; performing azimuth IFFT; focusing and imaging to realize an imaging algorithm; comparing with the result of the initial imaging; and judging whether the side slope is deformed or not to realize a side slope monitoring algorithm and outputting a side slope monitoring result.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (8)

1. A multiple-shot multiple-receive imaging radar for slope monitoring, comprising:

the microstrip array antenna comprises M transmitting array antennas and N receiving array antennas, wherein the transmitting array antennas are used for transmitting electromagnetic waves, and the receiving array antennas are used for receiving the electromagnetic waves in the space, which are reflected back by the slope surface, of the transmitting electromagnetic waves;

the frequency modulation continuous wave radar radio frequency front end module comprises a plurality of radio frequency transceivers which are cascaded to form M transmitting channels and N receiving channels, wherein the M transmitting channels correspondingly and respectively transmit electromagnetic waves through the M transmitting array antennas, and the N receiving channels correspondingly and respectively receive the electromagnetic waves reflected by the slope surface through the N receiving array antennas; the reflected electromagnetic wave signals are subjected to frequency mixing processing, and intermediate frequency signals containing distance information and direction information are output;

the ADC module is used for converting the intermediate frequency signal into a digital signal;

the data storage module is used for storing the digital signals of the currently acquired side slope and reference side slope radar imaging result data;

the radar signal processing module is used for receiving the intermediate frequency signal output by the ADC module, performing digital signal processing on the intermediate frequency signal to finish slope imaging, and performing image comparison on the slope imaging and the reference slope radar imaging to judge whether the slope is deformed;

and the external data interaction interface module is used for receiving the result of the slope image comparison output by the radar signal processing module, outputting the slope image monitoring result to the outside and adjusting the radar related parameters.

2. The multiple-input multiple-output imaging radar for slope monitoring as claimed in claim 1, wherein one of the radio frequency transceivers is a master, the other radio frequency transceivers are slaves, a clock pin outputs the reference clock signal generated by a clock circuit and an external resonant circuit inside the master, and a clock buffer divides one path of the reference clock signal into multiple paths to provide synchronous clock reference signals for the other multiple paths of slaves, thereby realizing cascade connection.

3. The multiple shot multiple receive imaging radar for slope monitoring of claim 1 further comprising a data conversion module for converting the digital signals to a format customized to the radar signal processing module.

4. The radar of claim 3 wherein the ADC module is connected to the data conversion module via a high speed digital signal connector.

5. The multiple-shot multiple-reception imaging radar for slope monitoring according to claim 4, wherein the data conversion module comprises several same-model FPGAs, and each FFPA is responsible for converting ADC data output by one radio frequency transceiver; NOR Flash is connected with the outside of each FPGA to expand the storage capacity of the FPAG.

6. The multiple-input multiple-output imaging radar for slope monitoring as claimed in claim 1, wherein the external data interaction interface module comprises a network port communication circuit and a USB2.0 interface to serial port circuit, the network port communication circuit is used for outputting the slope monitoring result, and the USB2.0 interface to serial port circuit is used for adjusting some parameters of the whole radar system by an upper computer on a computer.

7. The multiple-input multiple-output imaging radar for slope monitoring according to claim 3, 4 or 5, further comprising a power supply module, which is composed of a power protection circuit, a dc voltage drop circuit, a linear voltage regulator circuit, a power filter, and a power management chip circuit, wherein an output terminal of the power protection circuit is connected to an input terminal of the dc voltage drop circuit, a first output terminal of the dc voltage drop circuit is connected to an input terminal of the power management chip, and an output terminal of the power management chip is respectively connected to the fm cw radar rf front-end module and the ADC module for supplying power thereto; the second output end of the direct current voltage reduction circuit is connected with a plurality of linear voltage stabilizing circuits for voltage reduction and then respectively supplies power to the data conversion module and the external data interaction interface module; and the second output end of the direct current voltage reduction circuit is also connected with a power management chip circuit to carry out voltage reduction and then respectively supply power to the data storage module and the radar signal processing module.

8. The multiple-shot multiple-reception imaging radar for slope monitoring according to claim 1, further comprising a memory module, formed of a plurality of memory chips, connected to the radar signal processing module in a T-topology.

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