Homologous multichannel pseudo satellite deformation monitoring system in GNSS denial environment

Abstract

The invention provides a homologous multichannel pseudo satellite deformation monitoring system in a GNSS denial environment, and relates to the field of geological deformation early warning and monitoring. The device comprises a pseudo satellite base station module, a transmitting antenna module, an infrared distance measurement module, a monitoring receiver, a monitoring data processing center and a high-definition camera device. The monitoring receiver is used for receiving observed quantities such as a Beidou micro base station signal output carrier phase and the like, the carrier phase double-difference data is used for monitoring the deformation condition, and due to the fact that the fluctuation of the carrier phase difference value is small, when a mountain and the like deform, the identification degree is high; when the carrier phase double-difference data changes greatly, the position point of the receiver can be checked and detected at a fixed point through the high-definition camera device, and further deformation confirmation is carried out.

Description

Technical Field

[0001] The present invention relates to the field of geological deformation early warning monitoring in situations such as landslides, deformations, depressions, etc. under GNSS denial conditions, and specifically refers to a homologous multi-channel pseudo-satellite deformation monitoring system under GNSS denial conditions. Background Art

[0002] With the construction of more and more railways and bridges, there are more and more safety accidents caused by landslides, bridge collapses and other problems. At present, the main way to deal with this problem is to use GPS differential technology to monitor landslides, bridge collapses and other problems. That is, by establishing differential stations, the monitoring receiver receives GNSS signals and differential information to perform high-precision positioning. However, in a GNSS-denied environment, how to solve the problem of address deformation monitoring and early warning is still quite difficult.

[0003] Pseudo-satellites can replace navigation satellites in areas where GNSS signals cannot cover by broadcasting GNSS-like signals. Pseudo-satellites are simple in structure, small in size, and easy to deploy, making them an excellent alternative to navigation satellites. Secondly, pseudo-satellite positioning technology is becoming more and more mature, with higher and higher positioning accuracy. The positioning accuracy based on carrier phase can reach centimeter level, meeting the requirements of geological deformation detection. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a homologous multi-channel pseudo-satellite deformation monitoring system, which utilizes its high stability and high positioning accuracy to solve the problems of geological deformation monitoring and early warning in a GNSS-denied environment.

[0005] The technical solution adopted by the present invention is:

[0006] A homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS denial environment, comprising:

[0007] Pseudo-satellite base station module, including multiple signal channels, using the same clock source between channels; used to broadcast GNSS-like signals through the transmitting antenna to cover the monitored area;

[0008] The transmitting antenna module is composed of multiple transmitting antennas, which are connected to the pseudo-satellite base station module through radio frequency cables. Each transmitting antenna corresponds to one signal channel. Multiple transmitting antennas are arranged with short spacing and erected on a tower at a specific height.

[0009] The infrared ranging module is installed together with the transmitting antenna module to measure the height of the transmitting antenna from the ground. It is used to monitor in real time whether the transmitting antenna module moves and report the status to the server through the built-in Internet of Things card.

[0010] The monitoring receiver is installed at multiple fixed points in the monitored area to receive multiple GNSS-like signals transmitted by the pseudo-satellite base station module, and upload the original observation information of the received multiple GNSS-like signals to the monitoring data processing center through the built-in Internet of Things card;

[0011] The monitoring data processing center includes a deformation monitoring unit and a monitoring data reporting unit. The deformation monitoring unit is used to perform real-time data processing on the original observation information uploaded by the monitoring receiver, analyze and calculate the position change of the monitoring receiver, obtain the deformation degree, and send it to the server through the monitoring data reporting unit;

[0012] The high-definition camera device is used to check the deformation of the corresponding monitoring receiver installation point at a fixed point under the control of the server.

[0013] Furthermore, it also includes a solar panel, which uses solar power to power the pseudo-satellite base station module and the monitoring receiver; the infrared ranging module is powered by a battery.

[0014] Furthermore, the monitoring data reporting unit includes a storage module and a 4G communication module. The storage module is used to store the monitoring data in real time, and the 4G communication module is used to report the monitoring results in real time and issue an early warning.

[0015] Furthermore, the specific processing process of the deformation monitoring unit includes:

[0016] (1) Obtain in real time the carrier phase of multiple GNSS-like signal raw observation information uploaded by a monitoring receiver at a fixed point and record it;

[0017] (2) Subtract the phases of multiple carrier waves from each other and calculate the average value, which is used as a reference value to determine whether deformation occurs.

[0018] The difference formula is:

[0019] Δφ n-m (i) = φ n (i)-φ m (i) (1)

[0020] In the formula, φ n (i) and φ m (i) are the carrier phases of satellites n and m at the i-th epoch, Δφ n-m (i) is the carrier phase difference between satellite n and satellite m at the i-th epoch;

[0021] According to formula (1), the reference value is:

[0022]

[0023] In the formula, is the average value of the carrier phase difference between satellite n and satellite m in N epochs, which is used as a reference value;

[0024] (3) Subtract the carrier phase difference at the current moment from the reference value at the current moment;

[0025] The difference calculation formula is:

[0026]

[0027] In the formula, Δφ n-m (H) is the carrier phase difference at the current epoch H, is the difference between the real-time monitored carrier phase difference and the reference value;

[0028] (4) When When more than half of them are greater than the monitoring threshold value, it is judged that deformation has occurred and an early warning is issued; if no deformation has occurred, the current reference value and the carrier phase difference are summed and averaged as the new reference value, and then return to step (3); the calculation formula is as follows:

[0029]

[0030] The advantages of the present invention compared with the prior art are:

[0031] In the present invention, the pseudo-satellite base station includes multiple channels, and the same clock source is used between the channels, so that strict synchronization of signals between the channels can be achieved, and the original observation information of different pseudo-satellite signals output by the monitoring receiver can be guaranteed to have the same change. Secondly, a multi-channel pseudo-satellite can transmit multiple navigation signals, and one channel corresponds to one transmitting antenna. The transmitting antenna adopts a short-spacing layout. Compared with other current pseudo-satellite monitoring methods, it is not necessary to deploy base stations at multiple points in a large range. It is only necessary to deploy a multi-channel pseudo-satellite at a fixed point. The multiple antennas adopt a short-spacing layout to avoid the near-far effect caused by the multi-point distribution, which can improve the positioning accuracy. Moreover, the multiple antennas adopt a short-spacing layout, and the signal space transmission channel state is consistent. The original observation amount information of the pseudo-satellite is received and analyzed by the receiver, which has high stability and accuracy. Secondly, the multi-channel pseudo-satellite has the advantages of small size and convenient deployment. Moreover, the deformation monitoring method based on the homologous multi-channel pseudo-satellite has high positioning accuracy, which greatly increases the reliability of deformation monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of a monitoring system according to an embodiment of the present invention.

[0033] Figure 2 It is a schematic diagram of a transmitting antenna module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] like Figure 1 , a homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS-denied environment, as follows:

[0036] In a flat area around the monitored area, a stable point is selected to build a transmission tower. The height of the transmission tower must ensure that the pseudo-satellite signal can cover the entire monitored area. Then, a control room is built at the bottom of the transmission tower to deploy pseudo-satellite base station modules. The pseudo-satellite base station module contains multiple signal channels, and the same clock source is used between channels. The pseudo-satellite base station broadcasts GNSS-like signals through the transmitting antenna to cover the monitored area.

[0037] The pseudo-satellite base station is also equipped with a 4G communication module and a pseudo-satellite state monitoring module. The pseudo-satellite state monitoring module monitors the operating state of the pseudo-satellite in real time and reports the operating state of the pseudo-satellite to the server in real time through the 4G communication module.

[0038] The transmitting antenna module consists of multiple transmitting antennas, which are connected to the pseudo-satellite base station module through radio frequency cables. Each transmitting antenna corresponds to one signal channel. Multiple antennas are arranged with short spacing, vertically on the ground and facing the mountain. Figure 2 As shown in the figure, a rectangular structure is adopted. Four antennas are arranged up and down, with a spacing of 5 meters. The spacing length is related to the monitoring range. Two antennas are arranged at the top and two antennas are arranged at the bottom. The length of the long side is related to the coverage range. The schematic diagram of the transmitting antenna module is shown in Figure 2 shown.

[0039] The infrared distance measurement module is installed together with the transmitting antenna module to measure the height of the transmitting antenna from the ground to avoid external factors such as wind and rain, which may cause the transmitting antenna to move and cause false warnings. It is used to monitor whether the transmitting antenna module moves in real time and report the status to the server through the built-in IoT card.

[0040] The monitoring receiver is set up at multiple fixed points in the monitored area to receive multiple signals transmitted by pseudo-satellites. The monitoring receiver has a built-in Internet of Things card, which can upload the received original observation information to the monitoring data processing center via the wireless network.

[0041] The monitoring data processing center includes a deformation monitoring unit and a monitoring data reporting unit. The deformation monitoring unit performs real-time data processing on the original observation information uploaded by the monitoring receiver, analyzes and solves the position of the monitoring receiver, obtains the deformation degree, and sends it to the server through the monitoring data reporting unit;

[0042] The monitoring data reporting unit includes a storage module and a 4G communication module. The storage module stores the monitoring data in real time, and the 4G communication module reports the monitoring results in real time for early warning.

[0043] A high-definition camera is installed on the transmission tower. When the server receives the monitoring data uploaded by the monitoring data reporting unit, if a monitoring alarm occurs, the server controls the high-definition camera to check the situation of the corresponding receiver installation point. If deformation does occur, emergency processing is carried out. If it is a false alarm, an alarm is triggered.

[0044] Furthermore, the deformation monitoring system is also equipped with a solar panel, which powers the pseudo-satellite base station and the monitoring receiver through solar power generation; and the infrared ranging module is powered by a battery and has a power prompt function.

[0045] Furthermore, the data processing in the deformation monitoring unit includes the following steps:

[0046] 1. Obtain the carrier phase information of multiple pseudo-satellite signal raw observations uploaded by a monitoring receiver at a fixed point in real time and record its value.

[0047] 2. The carrier phases of the initial multiple pseudo-satellites are subtracted from each other as a reference value for judging whether deformation has occurred, and compared with the difference at the current moment. Due to the homologous design, after the difference, the clock deviation and clock drift between the multiple signals are consistent, which can be eliminated by the difference, so the value has a high stability. If the difference is greater than the monitoring threshold, an early warning is issued and the staff is notified to check. If there is no change, the current data and the reference value are summed and averaged as the reference value for judging whether deformation has occurred at the next moment, and the process is repeated in sequence.

[0048] The difference formula is as follows:

[0049] Δφ n-m (i) = φ n (i)-φ m (i) (1)

[0050] In the formula, φ n (i) φ m (i) are the carrier phases of satellites n and m at the i-th epoch, Δφ n-m (i) is the carrier phase difference between satellite n and satellite m at the i-th epoch.

[0051] According to formula (1), the initial reference value is

[0052]

[0053] is the average value of the carrier phase difference between satellite n and satellite m in N epochs.

[0054] 3. Subtract the current carrier phase difference from the current reference value;

[0055] The difference calculation formula is:

[0056]

[0057] In the formula, Δφ n-m (H) is the carrier phase difference at the current epoch H, The difference between the real-time monitored carrier phase difference and the reference value is There are 6 differences.

[0058] 4. In general, when the pseudo-satellite base station uses a constant temperature crystal oscillator, the carrier phase difference fluctuates within ±0.01. When more than half of the six differences are greater than 0.01, it is judged that deformation has occurred. If no deformation has occurred, the current monitoring value and the carrier phase difference of the initial multiple epochs are summed as the new reference value, and then return to 3 for continuous iteration; the formula is as follows:

[0059]

[0060] The above is only a specific example of the present invention, but the protection scope of the present invention is not limited thereto. Within the technical scope disclosed by the present invention, all conceivable changes should be included in the scope of the present invention.

Claims

1. A homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS-denied environment, characterized in that: include: The pseudo-satellite base station module contains multiple signal channels, and the channels use the same clock source; Used to broadcast GNSS-like signals through the transmitting antenna to cover the monitored area; The transmitting antenna module is composed of multiple transmitting antennas, which are connected to the pseudo-satellite base station module through radio frequency cables. Each transmitting antenna corresponds to one signal channel. Multiple transmitting antennas are arranged with short spacing and erected on a tower at a specific height. The infrared ranging module is installed together with the transmitting antenna module to measure the height of the transmitting antenna from the ground. It is used to monitor in real time whether the transmitting antenna module moves and report the status to the server through the built-in Internet of Things card. The monitoring receiver is installed at multiple fixed points in the monitored area to receive multiple GNSS-like signals transmitted by the pseudo-satellite base station module, and upload the original observation information of the received multiple GNSS-like signals to the monitoring data processing center through the built-in Internet of Things card; The monitoring data processing center includes a deformation monitoring unit and a monitoring data reporting unit. The deformation monitoring unit is used to perform real-time data processing on the original observation information uploaded by the monitoring receiver, analyze and calculate the position change of the monitoring receiver, obtain the deformation degree, and send it to the server through the monitoring data reporting unit; The high-definition camera device is used to check the deformation of the corresponding monitoring receiver installation point at a fixed point under the control of the server.

2. The homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS-denied environment according to claim 1, characterized in that: It also includes a solar panel, which uses solar power to power the pseudo-satellite base station module and the monitoring receiver; the infrared ranging module is powered by a battery.

3. The homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS-denied environment according to claim 1, characterized in that: The monitoring data reporting unit includes a storage module and a 4G communication module. The storage module is used to store monitoring data in real time, and the 4G communication module is used to report monitoring results in real time and issue an early warning.

4. The homologous multi-channel pseudo-satellite deformation monitoring system in a GNSS-denied environment according to claim 1, characterized in that: The specific processing process of the deformation monitoring unit includes: (1) Obtain in real time the carrier phase of multiple GNSS-like signal raw observation information uploaded by a monitoring receiver at a fixed point and record it; (2) Subtract the phases of multiple carrier waves from each other and calculate the average value, which is used as a reference value to determine whether deformation occurs. The difference formula is: Df n-m (i)=φ n (i)-φ m (i) (1) In the formula, φ n (i) and φ m (i) are the carrier phases of satellites n and m at the i-th epoch, Δφ n-m (i) is the carrier phase difference between satellite n and satellite m at the i-th epoch; According to formula (1), the reference value is: In the formula, is the average value of the carrier phase difference between satellite n and satellite m in N epochs, which is used as a reference value; (3) Subtract the carrier phase difference at the current moment from the reference value at the current moment; The difference calculation formula is: In the formula, Δφ n-m (H) is the carrier phase difference at the current epoch H, is the difference between the real-time monitored carrier phase difference and the reference value; (4) When When more than half of them are greater than the monitoring threshold value, it is judged that deformation has occurred and an early warning is issued; if no deformation has occurred, the current reference value and the carrier phase difference are summed and averaged as the new reference value, and then return to step (3); the calculation formula is as follows:

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