Ethernet-based time-division multiplexing multi-channel ground penetrating radar system and method

Abstract

The application discloses a time division multiplexing multi-channel ground penetrating radar system and method based on Ethernet, which comprises a control host and a plurality of radar detectors connected with the control host; the control host comprises a control unit and a ranging unit connected with the control unit; the radar detector comprises a radar detection module and a man-machine interaction module, and the radar detection module is connected with the man-machine interaction module and the control unit respectively; the control unit is used for receiving pulses sent by the ranging unit and outputting a plurality of same-phase synchronous clocks to each radar detection module according to the pulses; the man-machine interaction module applies different time delays to the synchronous clocks, triggers a pulse source as a reference signal and then carries out sampling, so that interference caused by simultaneous triggering of pulse sources in the plurality of radar detectors is avoided; the application only increases an Ethernet switch and a man-machine interaction module, simplifies the structure of the multi-channel ground penetrating radar system and reduces manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of ground penetrating radar technology, specifically to a time-division multiplexing multichannel ground penetrating radar system and method based on Ethernet. Background Technology

[0002] Ground-penetrating radar (GPR), a non-destructive testing device that uses high-frequency electromagnetic waves to obtain information about the distribution patterns of underground media, is a mainstream method for detecting defects such as voids and cracks in tunnel linings. It offers advantages such as speed and high resolution. Traditional multi-channel GPR systems typically consist of a control unit, detectors, and a host computer. Based on the antenna configuration within the detector, they can be divided into two systems: multiple-transmitter-multiple-receiver (MPMR) and single-transmitter-multiple-receiver (SMR). The former usually consists of a pair of transmitting and receiving antennas and a transceiver unit forming a detector unit, allowing for the simultaneous configuration of multiple detector units across different frequency bands to improve the radar's detection accuracy and range. The latter typically integrates one transmitting antenna and multiple receiving antennas into the same detector unit. These receiving antennas can each be configured with a separate receiver or share a single receiver via a switch, but only one frequency band can be configured at a time, suitable for applications such as 3D imaging.

[0003] Multi-channel ground-penetrating radars with multiple transmitters and receivers are equivalent to multiple single-channel ground-penetrating radars operating simultaneously without interference, in terms of working principle and performance. By configuring multiple different operating frequency bands, the accuracy and range of underground detection can be significantly improved. Currently, the number of channels in existing multi-channel ground-penetrating radar systems is limited and fixed. For application scenarios with specific channel requirements, special customization is usually required, and the number of customizable channels is generally fixed at a few and cannot be modified arbitrarily, thus limiting the flexibility and scalability of use. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet, which enables multiple channels to work simultaneously during radar detection without interfering with each other.

[0005] This invention is achieved through the following technical solution:

[0006] A time-division multiplexing multichannel ground-penetrating radar system based on Ethernet includes a control host and multiple radar detectors connected thereto.

[0007] The control host includes a control unit and a ranging unit connected to it; the radar detector includes a radar detection module and a human-machine interaction module, and the radar detection module is connected to the human-machine interaction module and the control unit respectively.

[0008] The control unit is used to receive pulses sent by the ranging unit and output multiple synchronous clocks with the same phase to each radar detection module according to the pulses. The human-machine interaction module is used to delay the synchronous clocks, and the delays of each radar detection module are different.

[0009] Preferably, the control unit is connected to the radar detection module via an Ethernet switch.

[0010] Preferably, the ranging unit is a ranging wheel or a Doppler.

[0011] Preferably, the radar detection module includes a narrow pulse source, an equivalent sampling receiver, and a transceiver antenna. The human-machine interaction module is connected to the equivalent sampling receiver. The equivalent sampling receiver is connected to the control unit and the pulse source, respectively. The pulse source and the equivalent sampling receiver are connected to the transceiver antenna, respectively.

[0012] Preferably, the control unit is also connected to a positioning module.

[0013] Preferably, the human-computer interaction module is a rotary encoder and a digital tube connected thereto.

[0014] A method for a time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet, characterized by comprising the following processes:

[0015] The pulse generated by the ranging unit is sent to the control unit as a reference clock.

[0016] The control unit sends the reference clock as a synchronization clock to each radar detector;

[0017] Each radar detector uses a delayed synchronization clock as a reference clock to trigger radar echo sampling. The synchronization clock delays for each radar detector are different.

[0018] Preferably, the control unit divides the base clock and sends it as a synchronization clock to each radar detector.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention provides a time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet, suitable for applications requiring the simultaneous operation of multiple radar detectors with the same or different frequency bands, such as tunnel lining monitoring. This invention connects the control host and multiple radar detectors via Ethernet, facilitating rapid expansion of the channel count. By adding a human-machine interface module to each radar detector, it is easy to distinguish radar detectors with the same topology. The radar detector can automatically set its IP address based on the human-machine interface module and apply different delays to the synchronization signal as a reference signal to trigger the pulse source before sampling. This not only facilitates rapid expansion of the channel count but also avoids interference caused by multiple radar detectors operating simultaneously. This invention only adds an Ethernet switch and a human-machine interface module, resulting in a simple system structure and low cost. Attached Figure Description

[0021] Figure 1 This is a topology diagram of the Ethernet-based time-division multiplexing multichannel ground-penetrating radar system of the present invention;

[0022] Figure 2 This is a diagram showing the clock relationship of the radar system of the present invention during operation; Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0024] See Figure 1 A time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet includes a control host, which is connected to a host computer and multiple radar detectors via Ethernet.

[0025] The control host includes a control unit and a positioning unit and a ranging unit connected thereto; the radar detector includes a radar detection module and a human-machine interaction module, with the radar detection module connected to the human-machine interaction module and the control unit respectively.

[0026] The control unit is used to send a synchronization clock to each radar detection module, and the human-machine interaction module is used to delay the synchronization clock, and the delay is different for each radar detection module.

[0027] The control host also includes an Ethernet switch and a power module. The control unit is a timing control motherboard, which is connected to the host computer via the Ethernet switch. Each radar detector is connected to the Ethernet switch. The power module is connected to the Ethernet switch, the timing control motherboard, and multiple radar detectors. The ranging unit is a ranging wheel or a Doppler, and the positioning unit is a GPS positioning module.

[0028] The timing control motherboard connects to the switch via Ethernet and is assigned a unique IP address. The GPS positioning module connects to the timing control motherboard via a serial port to obtain the current geographical location. The Doppler ranging radar has one of its ranging wheels that can be selectively connected to the control motherboard. Each ranging wheel outputs a pulse signal every time the radar system moves a set distance, serving as a trigger signal for the detector to collect data. The number of pulses multiplied by the set distance is recorded as the radar's mileage. When the timing control motherboard receives the pulse signal, it can choose to input it directly or divide it into multiple clock buffer chips (groups), ensuring that the multiple output clocks have the same phase.

[0029] In this embodiment, a 14-channel radar system is designed, and the clock buffer chip (group) should be one input and fourteen outputs or one input and sixteen outputs (two channels are spares). Additionally, when no external Doppler ranging radar or ranging wheel is connected, the timing control motherboard can actively output a pulse signal of a set frequency to the clock buffer chip (group).

[0030] The radar detection module includes a narrow pulse source, an equivalent sampling receiver, and a transceiver antenna. The human-machine interaction module is connected to the equivalent sampling receiver. The equivalent sampling receiver interacts with the control unit and the pulse source, respectively. The pulse source and the equivalent sampling receiver are connected to the transceiver antenna, respectively.

[0031] The radar detector is connected to the control host via a multi-core cable. Four cores are used as standard 100 Mbps Ethernet transmission lines to connect to the switch in the control host, two cores are connected to the output clock of the control host, and two cores are connected to the output power of the control host.

[0032] In this embodiment, an 8-core Gigabit Ethernet drag chain cable with double shielding is used, and the cable length of each channel is consistent. This results in high signal transmission quality between the control host and the radar detector, and the synchronization clock output by the control host arrives at different detectors with the same time delay. The pulse source is configured with different frequency bands according to the needs of the detection task. The equivalent sampling receiver has an FPGA or microcontroller as a processor, capable of receiving the synchronization clock from the control host, controlling the human-machine interface module, triggering the pulse source, and sampling the electromagnetic echo signal from the receiving antenna.

[0033] The human-computer interaction module consists of two parts: input and display. The preferred input method is a 4-digit, 16-range rotary encoder, and the display uses a single-digit digital tube.

[0034] This Ethernet-based time-division multiplexing multichannel ground-penetrating radar system offers extremely low cost and convenient numbering of detectors with the same topology. For different numbers, the sampling modules are assigned different IP addresses, and the synchronization signals sent by the control host are delayed differently. This avoids interference caused by the equivalent sampling receivers in the detectors simultaneously triggering pulse sources, and also facilitates the expansion of the number of channels in the control host.

[0035] In this embodiment, the host computer is a computer or mobile phone with specific software installed, which is stably connected to the control host via a wired or wireless network. When the radar system is working, the operating parameters such as the radar system's operating mode, frequency division coefficient, detector trigger frequency, and number of detector sampling points are set, and the test data returned by the detector via Ethernet is stored.

[0036] The working principle of the Ethernet-based time-division multiplexing multichannel ground-penetrating radar system provided in this embodiment will be explained in detail below.

[0037] Assume the ground-penetrating radar system has 14 channels. An external pulse generated by the Doppler radar serves as the reference clock with a period of T / 2. The radar control unit divides this reference clock by two to serve as the synchronization clock, with a period of T. The operating repetition frequency of the pulse source in the radar detector is set to f. clk .

[0038] Before the ground-penetrating radar system begins operation, the rotary encoder switches on the human-machine interface modules of the 14 radar detectors are set to 1-14 respectively; commands are sent from the host computer to the control host and radar detectors to set the radar control host to divide the external pulse by two, and the operating frequency of the pulse source in the radar detector is set to f. clk .

[0039] Once the ground-penetrating radar system starts operating, the Doppler radar will output a pulse after the system undergoes a certain displacement. Assuming the system moves at a constant speed, the pulse period generated by the Doppler radar is denoted as T / 2. Since the control host is configured to divide the external pulse by two, the timing control main board first divides the external signal frequency and then outputs 14 synchronous clocks with the same phase and a period of T to the radar detectors.

[0040] The repetition frequency of the pulse source in the radar detector is f clk However, the duration of the pulse is much shorter than f. clk Therefore, 1 / f clk The time slot is divided into 14 equal time slots. The radar detector numbered n has a synchronization clock delay of n*1 / (14*f). clk It serves as a reference clock in the radar detector to trigger the pulse source.

[0041] The radar detector uses the following scheme to achieve the synchronization clock delay:

[0042] In the equivalent sampling receiver, the FPGA multiplies the input clock of the external crystal oscillator through an internal PLL. Typically, the FPGA's internal clock F after PLL multiplication is... PLL (Typically 200MHz) is much larger than f clk (Typically 500kHz). When the FPGA receives the rising edge of the synchronization signal, it enables the internal counter to count the FPGA's internal clock (the count value is denoted as N). When N*1 / F... PLL Greater than n*1 / (14*f) clk The rising edge output is used as the internal control pulse source and sampling reference clock of the FPGA, with a maximum delay error of 1 / F. PLL .

[0043] Based on the above scheme, since the reference clocks of the trigger pulse sources of the 14 radar detectors are out of phase by a set phase, the pulses radiated by the transmitting antenna are never in the same time slot, thus enabling the 14 radar detectors to operate without interference.

[0044] Finally, the signals sampled by the equivalent sampling receiver are packaged, aggregated via an Ethernet switch, and sent to the host computer for real-time display and storage. Specifically, the packaged data for each radar detector includes the current identification number of that radar detector, thus distinguishing data collected by different radar detectors.

[0045] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet, characterized in that, This includes the control unit and multiple radar detectors connected to it; The control host includes a control unit and a ranging unit connected to the control unit; The radar detector includes a radar detection module and a human-machine interaction module. The control unit is connected to the radar detection module via an Ethernet switch. The radar detection module includes an equivalent sampling receiver. The human-machine interaction module is connected to the equivalent sampling receiver and is used to set the radar detector number. The control unit is used to receive pulses sent by the ranging unit and output multiple synchronous clocks with the same phase to the equivalent sampling receiver of each radar detection module according to the pulses. The equivalent sampling receiver applies a different delay corresponding to the received synchronization clock according to the number set by the human-machine interaction module, and then uses it as a reference clock to trigger the radar detector to perform sampling.

2. The Ethernet-based time-division multiplexing multi-channel ground-penetrating radar system according to claim 1, characterized in that, The ranging unit is a ranging wheel or a Doppler.

3. The Ethernet-based time-division multiplexing multi-channel ground-penetrating radar system according to claim 1, characterized in that, The radar detection module includes a narrow pulse source, an equivalent sampling receiver, and a transceiver antenna. The human-machine interaction module is connected to the equivalent sampling receiver. The equivalent sampling receiver is connected to the control unit and the pulse source, respectively. The pulse source and the equivalent sampling receiver are connected to the transceiver antenna, respectively.

4. The Ethernet-based time-division multiplexing multi-channel ground-penetrating radar system according to claim 1, characterized in that, The control unit is also connected to a positioning module.

5. A time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet according to claim 1, characterized in that, The human-computer interaction module consists of a rotary encoder and a digital tube connected to it.

6. A method for a time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet as described in any one of claims 1-5, characterized in that, The process includes the following: The pulse generated by the ranging unit is sent to the control unit as a reference clock. The control unit sends the reference clock as a synchronization clock to each radar detector; Each radar detector uses a delayed synchronization clock as a reference clock to trigger radar echo sampling. The synchronization clock delays for each radar detector are different.

7. A method for a time-division multiplexing multi-channel ground-penetrating radar system based on Ethernet according to claim 6, characterized in that, The control unit divides the reference clock and sends it as a synchronization clock to each radar detector.

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