Anti-destruction warning system, method, device, storage medium and product

Abstract

The present invention discloses an anti-destruction warning system, method, device, storage medium and product. The system includes a first radar, a second radar, a third radar and a central processor. The first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line. Each radar radiates electromagnetic wave signals outward at the same time under the control of the central processor. The central processor judges twice whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data fed back by each radar. The first radar and the second radar are combined, and the second radar and the third radar are combined to perform the second judgment. The first radar and the second radar of the invention form an equivalent large receiving aperture elevation antenna array, and the second radar and the third radar form an equivalent large receiving aperture horizontal antenna array. While solving the angle measurement ambiguity problem, the radar equivalent receiving aperture is greatly expanded, and the angle measurement accuracy is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transmission line monitoring, and in particular relates to an anti-destruction early warning system, method, equipment, storage medium and product for overhead power transmission lines. Background Art

[0002] Overhead transmission lines are often damaged by external forces such as human factors, such as construction and large engineering vehicles invading the transmission corridor, which will threaten the safe operation of the transmission lines. At present, the commonly used line anti-external damage monitoring methods include:

[0003] (1) Manual inspection: Staff regularly inspect the lines, demarcate protected areas, hang safety warning signs, and provide safety training to operators at the construction site. This method has problems such as large staff requirements, high labor costs, and inability to monitor in real time.

[0004] (2) Deploy network video surveillance equipment on site and transmit video data to the monitoring center in real time through 3G / 4G / 5G and other means. Staff judge the external damage accidents through real-time viewing or image processing algorithms. This method has the disadvantages of being easily affected by weather and the monitoring angle of the video surveillance equipment, and being unable to provide timely warnings of external damage accidents.

[0005] (3) Millimeter-wave radar and vision are used for joint monitoring. The millimeter-wave radar detects the radial distance of the external damage dangerous object, and then combines the pixel information of the corresponding frame on the image to predict the distance between the power line and the external damage object. This method also relies on visual information and is easily affected by weather and monitoring angles. It has the disadvantages of being unable to provide timely warnings for external damage accidents.

[0006] The latter two monitoring methods rely on visual information, but visual perception is greatly reduced or even completely ineffective at night or in rainy and foggy weather. In addition, high-voltage power lines often cross mountainous areas, and fog in the mountains can also cause visual failure. Summary of the invention

[0007] The purpose of the present invention is to provide an anti-destruction warning system, method, device, storage medium and product to solve the problem that traditional technology relies on visual information, which is easily affected by weather and monitoring angle, resulting in poor monitoring ability or even failure.

[0008] The present invention solves the above technical problems through the following technical solutions: an anti-destruction warning system for overhead transmission lines, comprising a radar group and a central processing unit, wherein the radar group is arranged on an iron tower on one side of the overhead transmission line and is located below the overhead transmission line, and the radar group comprises a first radar, a second radar and a third radar; the first radar, the second radar and the third radar are respectively connected to the central processing unit; the first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line; the antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitting and multi-receiving antenna array and a vertical multi-transmitting and multi-receiving antenna array; the vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, and the radiation direction of the first radar, the second radar and the third radar points to the iron tower on the other side of the overhead transmission line;

[0009] Each radar in the radar group is used to simultaneously radiate electromagnetic wave signals outward under the control of the central processor; sample the target reflected wave to obtain the original ADC data received by each channel of the corresponding radar, and send the original ADC data of each radar to the central processor;

[0010] The central processing unit is used for:

[0011] Sending a synchronous pulse signal to each radar in the radar group, so that each radar radiates electromagnetic wave signals outward at the same time;

[0012] Based on the raw ADC data of the second radar, it is preliminarily determined whether the target has entered the protection area of ​​the overhead transmission line;

[0013] When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, a first inter-chip phase difference caused by different clock sources between the first radar and the second radar and a second inter-chip phase difference caused by different clock sources between the second radar and the third radar are obtained, and the raw ADC data of the first radar is phase-calibrated according to the first inter-chip phase difference; the raw ADC data of the third radar is phase-calibrated according to the second inter-chip phase difference;

[0014] Calculate the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar; calculate the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar;

[0015] Calculate the vertical range of the protection area based on the target distance monitored by the radar group and the catenary equation of the overhead transmission line;

[0016] Determining again whether the target has entered the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance;

[0017] When it is determined again that the target has entered the protection area of ​​the overhead transmission line, an early warning signal is issued.

[0018] Furthermore, the central processor is used to send a synchronization pulse signal to each radar in the radar group, specifically including:

[0019] The central processor simultaneously sends a test pulse to each radar in the radar group;

[0020] The central processor determines the transmission delay of the signal sent by the central processor to each radar in the radar group according to the time difference between each received feedback pulse; wherein each feedback pulse is a pulse sent by each radar in the radar group to the central processor after receiving the test pulse;

[0021] The central processor sends a synchronization pulse signal to each radar in the radar group according to the transmission delay.

[0022] Furthermore, the central processor is used to preliminarily determine whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar, specifically including:

[0023] The original ADC data of the second radar is processed to obtain the target distance, target horizontal angle and target elevation angle monitored by the second radar;

[0024] The lateral distance of the first target is calculated according to the target distance and the target horizontal angle monitored by the second radar, and the vertical distance of the first target is calculated according to the target distance and the target elevation angle monitored by the second radar;

[0025] A preliminary judgment is made as to whether the target has entered the protection area of ​​the overhead transmission line based on the first target lateral distance and the first target vertical distance.

[0026] Furthermore, the process of acquiring the first inter-chip phase difference and the second inter-chip phase difference is as follows:

[0027] Setting a test target directly in front of the second radar;

[0028] The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals to the test target simultaneously;

[0029] Each radar in the radar group sends the received test echo signal to the central processor respectively;

[0030] The central processing unit calculates the phase of each radar in the radar group for the same test target based on each test echo signal;

[0031] The actual phase difference between the first radar and the second radar is calculated based on the phases of the first radar and the second radar for the same test target; the actual phase difference between the second radar and the third radar is calculated based on the phases of the second radar and the third radar for the same test target;

[0032] The angle between the reflected wave of the test target and the normal line of the first radar and the second radar is calculated according to the distance between the first radar and the second radar, the installation height of the second radar, and the straight-line distance between the test target and the first radar and the second radar, and then the theoretical phase difference between the first radar and the second radar is calculated; the angle between the reflected wave of the test target and the normal line of the second radar and the third radar is calculated according to the distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar, and then the theoretical phase difference between the second radar and the third radar is calculated;

[0033] The first inter-chip phase difference between the first radar and the second radar is calculated according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; the second inter-chip phase difference between the second radar and the third radar is calculated according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

[0034] Further, the central processor is used to calculate the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar, specifically including:

[0035] Processing the ADC data after phase calibration of the first radar and the second radar to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar;

[0036] Calculate the vertical distance of the second target according to the target distance and the target elevation angle monitored by the first radar and the second radar;

[0037] The central processor is used to calculate the lateral distance of the second target according to the ADC data after the phase calibration of the second radar and the third radar, specifically including:

[0038] Processing the ADC data after phase calibration of the second radar and the third radar to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination;

[0039] The lateral distance of the second target is calculated according to the target distance and the target horizontal angle monitored by the second radar and the third radar in combination.

[0040] Further, the central processor is used to determine again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance, specifically including:

[0041] When the second target lateral distance is within the lateral range of the protection area, and the second target vertical distance is within the vertical range of the protection area, the target enters the protection area of ​​the overhead transmission line.

[0042] Based on the same concept, the present invention provides an anti-destruction early warning method for overhead transmission lines, wherein a radar group is provided on one side of the iron tower of the overhead transmission line, the radar group is located below the overhead transmission line and includes a first radar, a second radar and a third radar; the first radar, the second radar and the third radar are respectively connected to a central processing unit; the first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line; the antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitting and multi-receiving antenna array and a vertical multi-transmitting and multi-receiving antenna array; the vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, and the radiation direction of the first radar, the second radar and the third radar points to the iron tower on the other side of the overhead transmission line; the early warning method includes:

[0043] The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals outward simultaneously;

[0044] Each radar in the radar group sends the raw ADC data received by each channel thereof to the central processor;

[0045] The central processor preliminarily determines whether the target has entered the protection area of ​​the overhead transmission line based on the raw ADC data of the second radar;

[0046] When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, the central processing unit obtains the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar and the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar, and performs phase calibration on the original ADC data of the first radar according to the first inter-chip phase difference; and performs phase calibration on the original ADC data of the third radar according to the second inter-chip phase difference;

[0047] Calculate the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar; calculate the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar;

[0048] Calculate the vertical range of the protection area based on the target distance monitored by the radar group and the catenary equation of the overhead transmission line;

[0049] Determining again whether the target has entered the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance;

[0050] When it is determined again that the target has entered the protection area of ​​the overhead transmission line, an early warning signal is issued.

[0051] Furthermore, the central processor controls each radar in the radar group to radiate electromagnetic wave signals outward simultaneously, including:

[0052] The central processor simultaneously sends a test pulse to each radar in the radar group;

[0053] After receiving the test pulse, each radar in the radar group sends a feedback pulse to the central processor;

[0054] The central processor determines the transmission delay of the signal sent by the central processor to each radar in the radar group according to the time difference between each received feedback pulse;

[0055] The central processor sends a synchronization pulse signal to each radar in the radar group according to the transmission delay;

[0056] Each radar in the radar group receives the synchronization pulse signal at the same time, and radiates electromagnetic wave signals outward at the same time under the triggering of the synchronization pulse signal.

[0057] Furthermore, the central processor preliminarily determines whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar, including:

[0058] The central processing unit processes the original ADC data of the second radar to obtain the target distance, target horizontal angle and target pitch angle monitored by the second radar;

[0059] The lateral distance of the first target is calculated according to the target distance and the target horizontal angle monitored by the second radar, and the vertical distance of the first target is calculated according to the target distance and the target elevation angle monitored by the second radar;

[0060] A preliminary judgment is made as to whether the target has entered the protection area of ​​the overhead transmission line based on the first target lateral distance and the first target vertical distance.

[0061] Furthermore, the process of acquiring the first inter-chip phase difference and the second inter-chip phase difference is as follows:

[0062] Setting a test target directly in front of the second radar;

[0063] The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals to the test target simultaneously;

[0064] Each radar in the radar group sends the received test echo signal to the central processor respectively;

[0065] The central processing unit calculates the phase of each radar in the radar group for the same test target based on each test echo signal;

[0066] The actual phase difference between the first radar and the second radar is calculated based on the phases of the first radar and the second radar for the same test target; the actual phase difference between the second radar and the third radar is calculated based on the phases of the second radar and the third radar for the same test target;

[0067] The theoretical phase difference between the first radar and the second radar is calculated according to the distance between the first radar and the second radar, the installation height of the second radar, and the straight-line distance between the test target and the first radar and the second radar; the theoretical phase difference between the second radar and the third radar is calculated according to the distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar;

[0068] The first inter-chip phase difference between the first radar and the second radar is calculated according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; the second inter-chip phase difference between the second radar and the third radar is calculated according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

[0069] Further, calculating the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar includes:

[0070] Processing the ADC data after phase calibration of the first radar and the second radar to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar;

[0071] Calculate the vertical distance of the second target according to the target distance and the target elevation angle monitored by the first radar and the second radar;

[0072] Calculating the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar, including:

[0073] Processing the ADC data after phase calibration of the second radar and the third radar to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination;

[0074] The lateral distance of the second target is calculated according to the target distance and the target horizontal angle monitored by the second radar and the third radar in combination.

[0075] Furthermore, the catenary equation of the overhead transmission line is:

[0076] y = acosh(z / a);

[0077] Among them, y represents the height of a point on the overhead transmission line; z represents the distance between a point on the overhead transmission line and the starting point of the overhead transmission line; a represents a constant; and cosh represents the hyperbolic cosine function.

[0078] Further, judging again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance includes:

[0079] When the second target lateral distance is within the lateral range of the protection area, and the second target vertical distance is within the vertical range of the protection area, the target enters the protection area of ​​the overhead transmission line.

[0080] Based on the same concept, the present invention also provides an electronic device, including a memory, a processor, and a computer program / instruction stored in the memory, wherein the processor executes the computer program / instruction to implement the anti-destruction warning method as described above.

[0081] Based on the same concept, the present invention also provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the anti-destruction warning method as described above is implemented.

[0082] Based on the same concept, the present invention also provides a computer program product, including a computer program / instruction, which implements the anti-damage warning method as described above when executed by a processor.

[0083] Beneficial Effects

[0084] Compared with the prior art, the advantages of the present invention are:

[0085] Each radar in the radar group of the present invention has a horizontal antenna and an elevation antenna, and the polarization directions of the two are perpendicular to each other. The first radar and the second radar form an elevation antenna array with an equivalent large receiving aperture, and the second radar and the third radar form an equivalent large receiving aperture horizontal antenna array. While solving the angle measurement ambiguity problem, the radar equivalent receiving aperture is greatly expanded, and the angle measurement accuracy is greatly improved. The pure solid state meets the angle measurement accuracy of SAR imaging, thereby improving the accuracy of judging whether the target enters the protection area of ​​the overhead transmission line. At the same time, the present invention does not require a mechanical structure, and compared with the visual sensor, it has all-day and all-weather perception capabilities.

[0086] The present invention realizes frame synchronization and chip coherent synchronization between radars, so that the angle detection of the radar group in the horizontal and elevation directions is combined into an equivalent large-aperture two-dimensional radar array, which greatly improves the angle measurement accuracy of the radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0088] Figure 1 is a structural block diagram of an anti-destruction warning system in an embodiment of the present invention;

[0089] Figure 2 is a schematic diagram of an equivalent virtual receiving antenna of a single radar in a radar group in an embodiment of the present invention;

[0090] Figure 3 is a schematic diagram of an equivalent virtual receiving antenna of a combination of a second radar and a third radar in an embodiment of the present invention;

[0091] Figure 4 is a schematic diagram of the structure of the synchronization line group between each radar and the central processing unit in an embodiment of the present invention;

[0092] Figure 5 This is a schematic diagram of radar phase angle measurement in an embodiment of the present invention;

[0093] Figure 6 This is a scene diagram actually measured in an outdoor field in an embodiment of the present invention;

[0094] Figure 7 is a real-object imaging diagram of a tower crane formed by using the method of the present invention in an embodiment of the present invention;

[0095] Figure 8 It is a flow chart of the anti-destruction warning method in an embodiment of the present invention. DETAILED DESCRIPTION

[0096] The following is a clear and complete description of the technical solution in the present invention 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, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0097] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0098] Example 1

[0099] like Figure 1As shown, an anti-destruction warning system for overhead transmission lines provided by an embodiment of the present invention includes a radar group and a central processing unit. The radar group is arranged on an iron tower on one side of the overhead transmission line and is located below the overhead transmission line. The radar group includes a first radar, a second radar and a third radar; the first radar, the second radar and the third radar are respectively connected to the central processing unit; the first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line, that is, the three radars are arranged in an L shape; the antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitter and multi-receiver antenna array and a vertical multi-transmitter and multi-receiver antenna array; the vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, the radiation directions of the first radar, the second radar and the third radar all point to the iron tower on the other side of the overhead transmission line, and the radiation directions of the first radar, the second radar and the third radar are parallel. For the radar group, the second radar is taken as the origin of the three-dimensional coordinate system, the vertical line where the first radar and the second radar are located is the pitch direction, that is, the vertical direction (or Y-axis), the horizontal line where the second radar and the third radar are located is the azimuth direction, that is, the horizontal direction or the horizontal direction (or X-axis), and the normal of the second radar is the longitudinal direction (that is, the Z-axis), and the normal of the second radar points to the iron tower on the other side of the overhead transmission line.

[0100] Exemplarily, the antenna arrays of the first radar, the second radar, and the third radar all include a horizontal 2-transmit (TX1 / TX2) 2-receive (RX1 / RX2) antenna array and a vertical 2-transmit (TX3 / TX4) 2-receive (RX3 / RX4) antenna array, the spacing between the two horizontal transmitting antennas TX1 / TX2 is half a wavelength, the spacing between the two horizontal receiving antennas RX1 / RX2 is half a wavelength, the spacing between the two vertical transmitting antennas TX3 / TX4 is half a wavelength, and the spacing between the two vertical receiving antennas RX3 / RX4 is half a wavelength. This array arrangement of the radar group has the following advantages:

[0101] (1) In a single radar, such as Figure 2 As shown in the figure, both the horizontal and vertical directions (i.e., the elevation directions) are equivalent to four receiving antennas with a spacing of half a wavelength. Therefore, a single radar can measure the angle of the target within a range of ±90° in the horizontal and elevation directions, i.e., within a range of 180° without ambiguity.

[0102] (2) In terms of isolation, for a single radar, the horizontal multi-transmitter and multi-receiver antenna array and the vertical multi-transmitter and multi-receiver antenna array have perpendicular polarization directions. The high polarization isolation feature enables the horizontal multi-transmitter and multi-receiver antenna array to work simultaneously without interference.

[0103] (3) In terms of angle measurement performance, the second radar and the third radar form a large-aperture receiving array in the horizontal direction after synchronization and phase calibration, that is, TX1, TX2, RX1, RX2 of the second radar and TX1, TX2, RX1, RX2 of the third radar form a virtual large receiving aperture in the horizontal direction; similarly, the second radar and the first radar form a large-aperture receiving array in the elevation direction after synchronization and phase calibration, that is, TX3, TX4, RX3, RX4 of the second radar and TX3, TX4, RX3, RX4 of the first radar form a virtual large receiving aperture in the elevation direction; the equivalent virtual large receiving aperture of the combination of the two radars in the horizontal or elevation direction is much larger than the receiving aperture of a single radar, which greatly improves the angle measurement accuracy.

[0104] like Figure 3 As shown, assuming that the spacing between the second radar and the third radar is 1 meter, that is, after phase calibration, the equivalent receiving aperture size of the second radar and the third radar in the horizontal direction is 1 meter, and the corresponding angular measurement resolution is 0.2 degrees, and the grating lobe problem of the virtual large aperture is eliminated by the 180° angular measurement range of a single radar; the same is true for the elevation direction, assuming that the spacing between the first radar and the second radar is 1 meter, that is, after phase calibration, the equivalent receiving aperture size of the first radar and the second radar in the elevation direction is 1 meter, and the corresponding angular measurement resolution is 0.2 degrees, and the grating lobe problem of the virtual large aperture is eliminated by the 180° angular measurement range of a single radar.

[0105] like Figure 1 As shown, the first radar, the second radar and the third radar are connected to the central processor through a synchronization line group and a high-speed data line respectively. The high-speed data line is used to send the original ADC data of the corresponding radar to the central processor, and the synchronization line group is used for the central processor to send pulse signals to the first radar, the second radar and the third radar. Figure 4 As shown, a socket of a synchronization line group is added to the first radar, the second radar, the third radar and the central processor. The synchronization line group is a twisted pair. The transmission path and the receiving path of the pulse signal are of equal length. The pulse signal sent by the central processor is divided into two after reaching the corresponding radar, one path goes to the trigger pin at the beginning of the radar frame, and the other path returns to the central processor via the twisted pair.

[0106] The first radar, the second radar and the third radar in the radar group all radiate electromagnetic wave signals outward at the same time under the triggering of the synchronous pulse signal sent by the central processor through the synchronous line group. The electromagnetic wave signals are reflected by the target, and the target reflected waves are sampled by each receiving channel of the first radar, the second radar and the third radar to obtain the original ADC data of each receiving channel of the first radar, the original ADC data of each receiving channel of the second radar and the original ADC data of each receiving channel of the third radar.

[0107] Since the first radar, the second radar and the third radar in the radar group are not connected, the radars in the radar group do not have a common clock source. In order to achieve frame trigger synchronization, clock synchronization and signal coherence of the radars in the radar group and ensure that the signals of different radars can be correctly fused and processed, the present invention controls the radars in the radar group to radiate electromagnetic wave signals outward at the same time through the central processor, and performs phase calibration on the ADC data of the receiving channel of each radar.

[0108] The working principle of radar is frame-by-frame data processing, which is called slow time processing. There are multiple chips (code pieces) modulation between frames, and the chip data processing is called fast time processing. The present invention starts from the fast and slow aspects. First, the slow cycle of each radar in the radar group must be synchronized, that is, frame trigger synchronization, and then the fast cycle synchronization is realized, that is, chip coherent synchronization.

[0109] The central processing unit is used to send a synchronization pulse signal to each radar in the radar group in a time-sharing manner, so that each radar radiates an electromagnetic wave signal outward at the same time, that is, to achieve frame synchronization of each radar. In a specific embodiment of the present invention, the central processing unit is used to send a synchronization pulse signal to each radar in the radar group in a time-sharing manner, specifically including:

[0110] The central processing unit simultaneously sends test pulses to the first radar, the second radar and the third radar in the radar group through each synchronization line group; after receiving the test pulse, the first radar, the second radar and the third radar in the radar group send feedback pulses to the central processing unit; the central processing unit determines the transmission delay of the central processing unit sending signals to the first radar, the second radar and the third radar in the radar group according to the time difference between the received feedback pulses; the central processing unit sends a synchronization pulse signal to the first radar, the second radar and the third radar in the radar group according to the transmission delay; the first radar, the second radar and the third radar in the radar group simultaneously receive the synchronization pulse signal, and simultaneously radiate electromagnetic wave signals outward under the triggering of the synchronization pulse signal, thereby realizing the frame trigger synchronization of each radar.

[0111] For example, assuming that the first radar receives the pulse signal sent by the central processor 1ns faster than the second radar, that is, the transmission delay is 1ns, then when sending the synchronization pulse signal, the central processor first sends the synchronization pulse signal to the second radar, and then sends the synchronization pulse signal to the first radar after a delay of 1ns, so that the first radar and the second radar receive the synchronization pulse signal sent by the central processor at the same time, thereby realizing frame trigger synchronization of the first radar and the second radar.

[0112] After receiving the original ADC data sent by each radar, the central processor first preliminarily determines whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar. In a specific embodiment of the present invention, the central processor is used to preliminarily determine whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar, specifically including:

[0113] The central processing unit processes the original ADC data of the second radar to obtain the target distance, target horizontal angle and target elevation angle monitored by the second radar; based on the trigonometric function, the first target lateral distance (i.e., the X-coordinate value of the target in the three-dimensional coordinate system) is calculated according to the target distance and target horizontal angle monitored by the second radar, and the first target vertical distance (i.e., the Y-coordinate value of the target in the three-dimensional coordinate system) is calculated according to the target distance and target elevation angle monitored by the second radar; and a preliminary judgment is made as to whether the target enters the protection area of ​​the overhead transmission line according to the first target lateral distance and the first target vertical distance.

[0114] The processing of the raw ADC data of the second radar specifically includes performing FFT (i.e., fast Fourier transform) processing on the raw ADC data in the distance dimension to obtain the distance dimension data; then performing FFT processing on the distance dimension data in the speed dimension to obtain the spectrum data; performing constant false alarm rate detection on the frequency data to obtain the target distance, target horizontal angle, and target elevation angle. Among them, the target distance refers to the straight-line distance between the target and the corresponding radar; the target horizontal angle refers to the horizontal angle between the line between the target and the corresponding radar and the normal of the radar, that is, the angle between the projection line of the line between the target and the corresponding radar on the XOZ plane and the normal of the radar (i.e., the Z axis); the target elevation angle refers to the vertical angle between the line between the target and the corresponding radar and the normal of the radar, that is, the angle between the projection line of the line between the target and the corresponding radar on the YOZ plane and the normal of the radar.

[0115] In order to avoid damage to overhead transmission lines, a certain range is drawn in the horizontal and vertical directions of the overhead transmission lines, and the range drawn in the horizontal and vertical directions forms a protection area for the overhead transmission lines; wherein, the horizontal direction of the overhead transmission line refers to the left and right sides of the axis with the overhead transmission line as the axis, and the vertical direction of the overhead transmission line refers to the upper and lower sides of the axis with the overhead transmission line as the axis. Exemplarily, the horizontal range (i.e., the lateral range) is [x1, x2], and the vertical range (i.e., the vertical range) is [y1, y2], x2-x1=80 meters, y2-y1=40 meters, x1, x2 are respectively the vertical distances between the points on the left and right sides of the overhead transmission line and the Z axis of the three-dimensional coordinate system, and y2, y1 are respectively the vertical distances between the points on the upper and lower sides of the overhead transmission line and the Z axis of the three-dimensional coordinate system.

[0116] Whether the target enters the protection area of ​​the overhead transmission line is preliminarily judged based on the first target lateral distance and the first target vertical distance, specifically including: when the first target lateral distance belongs to the lateral range [x1, x2], and the first target vertical distance belongs to the vertical range [y1, y2], it is preliminarily judged that the target enters the protection area of ​​the overhead transmission line.

[0117] When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, the central processing unit obtains the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar and the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar, and performs phase calibration on the original ADC data of the first radar according to the first inter-chip phase difference; and performs phase calibration on the original ADC data of the third radar according to the second inter-chip phase difference.

[0118] In order to accurately determine whether the target has entered the protection area of ​​the overhead transmission line, the first radar and the second radar are combined to form a virtual receiving large aperture in the elevation direction, that is, the original ADC data of the first radar and the second radar are combined; the second radar and the third radar are combined to form a virtual receiving large aperture in the horizontal direction, that is, the original ADC data of the second radar and the third radar are combined. Since the radars do not share a clock source, after the frame trigger synchronization, the coherence problem of fast time processing must be solved. The radar group of the distributed / satellite architecture needs to go through CP (cross path) to reconstruct the radar image, so that the three radars in the radar group are integrated in the horizontal and elevation dimensions, which greatly expands the aperture size of the radar after virtualization, greatly improves the angle measurement resolution and angle measurement accuracy of the radar group, and enables a single radar sensor to achieve practical application in the prevention of external damage to the transmission line.

[0119] Since the three radars in the radar group use their own crystal oscillators as clock sources, after the synchronization pulse signal sent by the central processor is sent to each radar at the same time, the radar starts FMCW (Frequency Modulated Continuous Wave) frequency modulation, and sends a certain number of chips to form a frame. Since the crystal oscillators of the three radars are not homologous, the initial test phase when starting the FM transmission is unpredictable. However, during the FM transmission of a frame, the phase of the same radar is synchronized, that is, the chips of the same radar are strictly coherent. Therefore, it is only necessary to obtain the phase difference between the first chips between the radars to achieve fast time synchronization through phase movement.

[0120] In a specific implementation of the present invention, the process of obtaining the first inter-chip phase difference and the second inter-chip phase difference is as follows:

[0121] Step A1: a test target is set in front of the second radar in the radar group; wherein, after the radar group is installed on the tower, a test target, such as a corner reflector, is set in front of the second radar.

[0122] Step A2: The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals to the test target at the same time; specifically, the central processing unit sends a synchronization pulse signal to each radar in the radar group according to the transmission delay, and each radar receives the synchronization pulse signal at the same time, and radiates electromagnetic wave signals to the corner reflector at the same time under the triggering of the synchronization pulse signal.

[0123] Step A3: Each radar in the radar group sends the received test echo signal to the central processor respectively; the central processor calculates the phase of each radar in the radar group for the same test target according to each test echo signal.

[0124] Exemplarily, the central processor extracts the corner reflector target from each test echo signal, and calculates the phase of the corner reflector target in the range dimension FFT, that is, obtains the phases of the three radars for the same corner reflector target.

[0125] Step A4: Calculate the actual phase difference between the first radar and the second radar according to the phases of the first radar and the second radar for the same test target; calculate the actual phase difference between the second radar and the third radar according to the phases of the second radar and the third radar for the same test target.

[0126] Step A5: Calculate the theoretical phase difference between the first radar and the second radar, and the theoretical phase difference between the second radar and the third radar.

[0127] like Figure 5 As shown, the calculation of the theoretical phase difference between the first radar and the second radar is taken as an example, where θ1 represents the angle between the first line and the second line, the first line refers to the line between the target and the first radar, the second line refers to the line between the target and the second radar, θ2 represents the angle between the first line and the vertical line from the target to the Y axis of the three-dimensional coordinate system, d1 represents the distance between the first radar and the second radar (i.e., the vertical distance), d2 represents the distance between the foot of the vertical line from the target to the Y axis of the three-dimensional coordinate system and the second radar, d3 represents the distance from the target to the Y axis of the three-dimensional coordinate system, d4 is the straight-line distance between the target and the second radar (i.e., the length of the second line), d6 is the straight-line distance between the target and the first radar (i.e., the length of the first line), and d5 represents the vertical distance from the second radar to the first line. Because the reflection of radar electromagnetic waves can be regarded as plane waves, d2 and d3, and the distance d7 between the foot of the vertical line from the second radar to the first radar and the first radar is the theoretical phase difference between the electromagnetic waves reflected by the target and reaching the first radar and the second radar.

[0128] Since d4 and d6 can be accurately measured, d3 can be calculated according to d4 and d2 (i.e., the installation height of the second radar), θ2 can be calculated according to d3, d1, and d2, and the angle θ3 between the second line and the perpendicular line from the target to the Y axis of the three-dimensional coordinate system can be calculated according to d2 and d3, and then θ1 can be calculated. According to θ1 and d4, the distance d8 between the foot of the perpendicular line from the second radar to the first line and the target can be calculated. Therefore, the theoretical phase difference between the first radar and the second radar is:

[0129] d7=d6-d8(1)

[0130] Similarly, the theoretical phase difference between the second radar and the third radar is calculated according to the distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar.

[0131] Step A6: Calculate the first inter-chip phase difference between the first radar and the second radar according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; calculate the second inter-chip phase difference between the second radar and the third radar according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

[0132] The actual phase difference and theoretical phase difference between the first radar and the second radar are calculated to obtain the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar. The ADC data of the first radar is moved in the time-frequency domain according to the first inter-chip phase difference to compensate for the chip phase offset, and the chip phase calibration between the first radar and the second radar is achieved in a soft way. Similarly, the actual phase difference and theoretical phase difference between the second radar and the third radar are calculated to obtain the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar. The ADC data of the third radar is moved in the time-frequency domain according to the second inter-chip phase difference to compensate for the chip phase offset, and the chip phase calibration between the second radar and the third radar is achieved in a soft way.

[0133] After frame trigger synchronization and inter-chip phase calibration, the first radar, the second radar and the third radar form a virtual two-dimensional large-aperture multi-transmitter multi-receiver radar. Assuming that the operating frequency of each radar is 80GHz, the three radars can be understood as the same radar installed in three different positions. The distance between the first radar and the second radar is 1 meter, and the distance between the second radar and the third radar is 1 meter. The formula for radar angular resolution is:

[0134] (2)

[0135] Among them, A θrepresents the radar angular resolution, Nt represents the number of transmitting antennas, Nr represents the number of receiving antennas, and Nt*Nr represents the virtual array length at half-wavelength distance. At an operating frequency of 80 GHz, a wavelength is 3.75 mm, and the length of a half-wavelength is 1.875 mm. When the radar spacing is 1 meter, the corresponding number of half-wavelengths is 1000 / 1.875=533.3, that is, at a spacing of 1 meter, Nt*Nr is equal to 533.3. Substituting this value into formula (2), the radar's angular resolution in the horizontal direction is about 0.2 degrees. 0.2 degrees means that the radar can distinguish two objects 1 meter apart in the horizontal direction at 300 meters. This angular accuracy has even surpassed the accuracy of the current radar + visual fusion measurement, and there is no defect that the visual sensor is easily affected by weather and environment. Based on the above analysis, it can be seen that the distance between the second radar and the third radar in the horizontal direction and the distance between the second radar and the first radar in the elevation direction can be adjusted according to the anti-destruction warning distance requirements.

[0136] The central processor is used to calculate the vertical distance of the second target (i.e., the Y coordinate value of the target in the three-dimensional coordinate system) according to the ADC data after the phase calibration of the first radar and the second radar; and calculate the lateral distance of the second target (i.e., the X coordinate value of the target in the three-dimensional coordinate system) according to the ADC data after the phase calibration of the second radar and the third radar. That is, the virtual receiving large aperture obtained by the combination of the first radar and the second radar is used to perform high-precision measurement of the target in the elevation direction, and the virtual receiving large aperture obtained by the combination of the second radar and the third radar is used to perform high-precision measurement of the target in the horizontal direction.

[0137] In a specific embodiment of the present invention, the central processor is used to calculate the vertical distance of the second target according to the ADC data after the phase calibration of the first radar and the second radar, specifically including:

[0138] Processing the ADC data after phase calibration of the first radar and the second radar (including FFT and constant false alarm rate detection) to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar;

[0139] Based on the trigonometric function, the vertical distance of the second target is calculated according to the target distance and the target elevation angle monitored by the first radar and the second radar.

[0140] Similarly, the central processor is used to calculate the lateral distance of the second target according to the ADC data after the phase calibration of the second radar and the third radar, specifically including:

[0141] Processing the ADC data after phase calibration of the second radar and the third radar (i.e., including FFT and constant false alarm rate detection) to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination;

[0142] The lateral distance of the second target is calculated based on the trigonometric function according to the target distance and the target horizontal angle monitored by the second radar and the third radar in combination.

[0143] The overhead transmission line is fixed and pulled by the iron towers at both ends. Therefore, the surface of the overhead transmission line is a catenary structure. The catenary equation is used to represent the surface of the overhead transmission line. The specific formula is:

[0144] y=acosh(z / a) (3)

[0145] Among them, y represents the height of a certain point on the overhead transmission line; z represents the distance between a certain point on the overhead transmission line and the starting point of the overhead transmission line; cosh represents the hyperbolic cosine function; a represents a constant, which represents the ratio of the tension of the catenary to the gravity. The constant a in the catenary equation can be calculated by the distance between the two towers, the length of the overhead transmission line and the height difference between the two ends of the overhead transmission line. The catenary equation (3) can be used to obtain the entire overhead transmission line, which solves the defect that the radar cannot effectively detect the entire overhead transmission line. The radar only needs to accurately detect the longitudinal distance of the possible external damage target, and then the height of the overhead transmission line corresponding to the current position of the external damage target can be calculated according to formula (3).

[0146] The first radar, or the second radar, or the third radar, or the combination of the first radar and the second radar, or the combination of the second radar and the third radar can monitor the target distance. For example, the ADC data of the first radar and the second radar are subjected to FFT and constant false alarm rate detection to obtain the target distance monitored by the combination of the first radar and the second radar. The target distance is projected onto the Z axis, and the projection distance (i.e., the longitudinal distance of the target or the Z coordinate value of the target in the three-dimensional coordinate system) is used as z in formula (3). The height of the overhead transmission line corresponding to the current position of the target can be calculated. y . According to the height y The vertical range of the protection area can be re-determined by comparing the vertical range of the protection area with the vertical range of the overhead transmission line. For example, the vertical range of the protection area is y2-y1=40 meters, and the re-determined vertical range of the protection area is [y-20, y+20], which solves the problem that the radar cannot detect the entire overhead transmission line and realizes the accurate determination of the vertical range of the protection area.

[0147] The central processing unit determines again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance, and sends out a warning signal when it is determined again that the target enters the protection area of ​​the overhead transmission line. In a specific embodiment of the present invention, the central processing unit determines again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance, including:

[0148] When the lateral distance of the second target is within the lateral range of the protection area (for example, [x1, x2]), and the vertical distance of the second target is within the vertical range of the protection area (for example, [y-20, y+20]), the target enters the protection area of ​​the overhead transmission line, and the sound and light system and the remote system are linked to issue warnings and records.

[0149] Figure 6 The working scene diagram of the tower crane (external destruction target) is shown. Figure 7 The tower crane image using the method of the present invention is shown, wherein the tower crane image is in the box, the horizontal axis is the radar horizontal distance measurement value (i.e. the horizontal distance information of the tower crane), and the vertical axis is the radar pitch distance measurement value (i.e. the height information of the tower crane). Figure 7 It can be seen that the three-dimensional shape of the tower crane can be obtained more clearly by adopting the method of the present invention, thereby achieving high-precision angle measurement and imaging of the tower crane.

[0150] Example 2

[0151] The overhead transmission line is fixed and pulled by two iron towers. In order to realize the anti-destruction warning of the overhead transmission line between the two iron towers, a radar group is installed on one of the iron towers, and the radar group is located below the overhead transmission line. The radar group can sense the overhead transmission line between the two iron towers in real time. Figure 1 As shown, the radar group includes the first radar, the second radar and the third radar; the first radar, the second radar and the third radar are connected to the central processor respectively; the first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line, that is, the three radars are arranged in an L shape; the antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitting and multi-receiving antenna array and a vertical multi-transmitting and multi-receiving antenna array; the vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, the radiation directions of the first radar, the second radar and the third radar all point to the iron tower on the other side of the overhead transmission line, and the radiation directions of the first radar, the second radar and the third radar are parallel. For the radar group, the second radar is taken as the origin of the three-dimensional coordinate system, the vertical line where the first radar and the second radar are located is taken as the elevation direction, that is, the vertical direction (or Y axis), the horizontal line where the second radar and the third radar are located is taken as the azimuth direction, that is, the horizontal direction or the horizontal direction (or X axis), the normal line of the second radar is taken as the longitudinal direction (that is, the Z axis), and the normal line of the second radar points to the iron tower on the other side of the overhead transmission line.

[0152] like Figure 8 As shown, an anti-damage warning method for overhead transmission lines provided by an embodiment of the present invention comprises the following steps:

[0153] Step 1: The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals outward simultaneously.

[0154] like Figure 1 As shown, the first radar, the second radar and the third radar are connected to the central processor through a synchronization line group and a high-speed data line respectively. The high-speed data line is used to send the original ADC data of the corresponding radar to the central processor, and the synchronization line group is used for the central processor to send pulse signals to the first radar, the second radar and the third radar. Since there is no connection between the first radar, the second radar and the third radar in the radar group, the radars in the radar group do not have a common clock source. In order to achieve frame trigger synchronization, clock synchronization and signal coherence of each radar in the radar group, and ensure that the signals of different radars can be correctly fused and processed, the present invention controls each radar in the radar group to radiate electromagnetic wave signals outward at the same time through the central processor, and performs phase calibration on the ADC data of each radar receiving channel.

[0155] The working principle of radar is frame-by-frame data processing, which is called slow time processing. There are multiple chips (code pieces) modulation between frames, and the chip data processing is called fast time processing. The present invention starts from the fast and slow aspects. First, the slow cycle of each radar in the radar group must be synchronized, that is, frame trigger synchronization, and then the fast cycle synchronization is realized, that is, chip coherent synchronization.

[0156] In the present invention, the radar frame trigger is provided by the central processor with a trigger pulse (i.e., a synchronization pulse signal), and the trigger pulse adopts a synchronization line group, i.e., a pair of twisted pairs, such as Figure 4 , the transmission path of the trigger pulse is equal to the receiving path. After the trigger pulse reaches the radar, it is divided into two, one path to the trigger pin at the beginning of the radar frame, and the other path returns to the central processor via a twisted pair. The distances between the central processor and the three radars in the radar group are inconsistent, so the lengths of the corresponding synchronization line groups are also inconsistent, which makes the present invention have excellent compatibility and robustness to installation errors. In a specific embodiment of the present invention, the central processor controls each radar in the radar group to radiate electromagnetic wave signals outward at the same time, including:

[0157] Step 1.1: The central processor sends test pulses to the three radars in the radar group simultaneously through each synchronization line group;

[0158] Step 1.2: After receiving the test pulse, each radar in the radar group sends a feedback pulse to the central processor;

[0159] Step 1.3: The central processor determines the transmission delay of the signal sent by the central processor to each radar in the radar group according to the time difference between each received feedback pulse;

[0160] Step 1.4: The central processor sends a synchronization pulse signal to each radar in the radar group according to the transmission delay;

[0161] Step 1.5: Each radar in the radar group receives the synchronization pulse signal at the same time, and radiates electromagnetic wave signals outward at the same time under the triggering of the synchronization pulse signal, thereby realizing the frame trigger synchronization of each radar.

[0162] For example, assuming that the first radar receives the pulse signal sent by the central processor 1ns faster than the second radar, that is, the transmission delay is 1ns, then when sending the synchronization pulse signal, the central processor first sends the synchronization pulse signal to the second radar, and then sends the synchronization pulse signal to the first radar after a delay of 1ns, so that the first radar and the second radar receive the synchronization pulse signal sent by the central processor at the same time, thereby realizing frame trigger synchronization of the first radar and the second radar.

[0163] Step 2: Each radar in the radar group sends the raw ADC data received by each channel to the central processor.

[0164] Each radar in the radar group sends its own raw ADC data to the central processor through the corresponding high-speed data line to facilitate the central processor to perform subsequent data processing.

[0165] Step 3: The central processor preliminarily determines whether the target enters the protection area of ​​the overhead transmission line based on the original ADC data of the second radar.

[0166] In a specific embodiment of the present invention, the central processor preliminarily determines whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar, specifically including:

[0167] Step 3.1: The central processor processes the raw ADC data of the second radar to obtain the target distance, target horizontal angle and target pitch angle monitored by the second radar;

[0168] Step 3.2: Based on trigonometric functions, the lateral distance of the first target (i.e., the X coordinate value of the target in the three-dimensional coordinate system) is calculated according to the target distance and the target horizontal angle monitored by the second radar, and the vertical distance of the first target (i.e., the Y coordinate value of the target in the three-dimensional coordinate system) is calculated according to the target distance and the target elevation angle monitored by the second radar;

[0169] Step 3.3: Preliminarily determine whether the target enters the protection area of ​​the overhead transmission line based on the first target lateral distance and the first target vertical distance.

[0170] The processing of the raw ADC data of the second radar specifically includes performing FFT (i.e., fast Fourier transform) processing on the raw ADC data in the distance dimension to obtain the distance dimension data; then performing FFT processing on the distance dimension data in the speed dimension to obtain the spectrum data; performing constant false alarm rate detection on the frequency data to obtain the target distance, target horizontal angle, and target elevation angle. Among them, the target distance refers to the straight-line distance between the target and the corresponding radar; the target horizontal angle refers to the horizontal angle between the line between the target and the corresponding radar and the normal of the radar, that is, the angle between the projection line of the line between the target and the corresponding radar on the XOZ plane and the normal of the radar (i.e., the Z axis); the target elevation angle refers to the vertical angle between the line between the target and the corresponding radar and the normal of the radar, that is, the angle between the projection line of the line between the target and the corresponding radar on the YOZ plane and the normal of the radar.

[0171] In order to avoid damage to overhead transmission lines, a certain range is drawn in the horizontal and vertical directions of the overhead transmission lines, and the range drawn in the horizontal and vertical directions forms a protection area for the overhead transmission lines; wherein, the horizontal direction of the overhead transmission line refers to the left and right sides of the axis with the overhead transmission line as the axis, and the vertical direction of the overhead transmission line refers to the upper and lower sides of the axis with the overhead transmission line as the axis. Exemplarily, the horizontal range (i.e., the lateral range) is [x1, x2], and the vertical range (i.e., the vertical range) is [y1, y2], x2-x1=80 meters, y2-y1=40 meters, x1, x2 are respectively the vertical distances between the points on the left and right sides of the overhead transmission line and the Z axis of the three-dimensional coordinate system, and y2, y1 are respectively the vertical distances between the points on the upper and lower sides of the overhead transmission line and the Z axis of the three-dimensional coordinate system.

[0172] Specifically, when the first target lateral distance belongs to the lateral range [x1, x2], and the first target vertical distance belongs to the vertical range [y1, y2], it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line.

[0173] Step 4: When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, the central processing unit obtains the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar and the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar.

[0174] In order to further accurately determine whether the target has entered the protection area of ​​the overhead transmission line, the first radar and the second radar are combined to form a virtual receiving large aperture in the elevation direction, that is, the original ADC data of the first radar and the second radar are combined for judgment; the second radar and the third radar are combined to form a virtual receiving large aperture in the horizontal direction, that is, the original ADC data of the second radar and the third radar are combined for judgment. Since the radars do not share a clock source, after the frame trigger synchronization, the coherence problem of fast time processing must be solved. The radar group of the distributed / satellite architecture needs to go through CP (cross path) to reconstruct the radar image, so that the three radars in the radar group are integrated in the horizontal and elevation dimensions, which greatly expands the aperture size of the radar after virtualization, greatly improves the angle measurement resolution and angle measurement accuracy of the radar group, and enables a single radar sensor to achieve practical application in the prevention of external damage to the transmission line.

[0175] Since the three radars in the radar group use their own crystal oscillators as clock sources, after the synchronization pulse signal sent by the central processor is sent to each radar at the same time, the radar starts FMCW (Frequency Modulated Continuous Wave) frequency modulation, and sends a certain number of chips to form a frame. Since the crystal oscillators of the three radars are not homologous, the initial test phase when starting the FM transmission is unpredictable. However, during the FM transmission of a frame, the phase of the same radar is synchronized, that is, the chips of the same radar are strictly coherent. Therefore, it is only necessary to obtain the phase difference between the first chips between the radars to achieve fast time synchronization through phase movement.

[0176] In a specific implementation of the present invention, the process of obtaining the first inter-chip phase difference and the second inter-chip phase difference is as follows:

[0177] Step 4.1: Set a test target directly in front of the second radar in the radar group.

[0178] After the radar group is installed on the tower, a test target, such as a corner reflector, is set in front of the second radar.

[0179] Step 4.2: The central processor controls each radar in the radar group to radiate electromagnetic wave signals to the test target simultaneously.

[0180] The central processing unit sends a synchronization pulse signal to each radar in the radar group according to the transmission delay. Each radar receives the synchronization pulse signal at the same time and radiates electromagnetic wave signals to the corner reflector at the same time under the triggering of the synchronization pulse signal.

[0181] Step 4.3: Each radar in the radar group sends the received test echo signal to the central processor.

[0182] Step 4.4: The central processing unit calculates the phase of each radar in the radar group for the same test target based on each test echo signal.

[0183] The central processing unit extracts the corner reflector target from each test echo signal and calculates the phase of the corner reflector target in the range dimension FFT, that is, the phase of the three radars for the same corner reflector target is obtained.

[0184] Step 4.5: Calculate the actual phase difference between the first radar and the second radar based on the phases of the first radar and the second radar for the same test target; calculate the actual phase difference between the second radar and the third radar based on the phases of the second radar and the third radar for the same test target.

[0185] Step 4.6: Calculate the theoretical phase difference between the first radar and the second radar, and the theoretical phase difference between the second radar and the third radar.

[0186] like Figure 5 As shown, the calculation of the theoretical phase difference between the first radar and the second radar is taken as an example, where θ1 represents the angle between the first line and the second line, the first line refers to the line between the target and the first radar, the second line refers to the line between the target and the second radar, θ2 represents the angle between the first line and the vertical line from the target to the Y axis of the three-dimensional coordinate system, d1 represents the distance between the first radar and the second radar (i.e., the vertical distance), d2 represents the distance between the foot of the vertical line from the target to the Y axis of the three-dimensional coordinate system and the second radar, d3 represents the distance from the target to the Y axis of the three-dimensional coordinate system, d4 is the straight-line distance between the target and the second radar (i.e., the length of the second line), d6 is the straight-line distance between the target and the first radar (i.e., the length of the first line), and d5 represents the vertical distance from the second radar to the first line. Because the reflection of radar electromagnetic waves can be regarded as plane waves, d2 and d3, and the distance d7 between the foot of the vertical line from the second radar to the first radar and the first radar is the theoretical phase difference between the electromagnetic waves reflected by the target and reaching the first radar and the second radar.

[0187] Since d4 and d6 can be accurately measured, d3 can be calculated based on d4 and d2 (i.e., the installation height of the second radar), θ2 can be calculated based on d3, d1, and d2, and the angle θ3 between the second line and the vertical line from the target to the Y axis of the three-dimensional coordinate system can be calculated based on d2 and d3, and then θ1 can be calculated. Based on θ1 and d4, the distance d8 between the foot of the vertical line from the second radar to the first line and the target can be calculated. Therefore, the theoretical phase difference between the first radar and the second radar is calculated according to formula (1). Similarly, the theoretical phase difference between the second radar and the third radar is calculated based on the horizontal distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar.

[0188] Step 4.7: Calculate the first inter-chip phase difference between the first radar and the second radar according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; calculate the second inter-chip phase difference between the second radar and the third radar according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

[0189] The actual phase difference and theoretical phase difference between the first radar and the second radar are calculated to obtain the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar. The ADC data of the first radar is moved in the time-frequency domain according to the first inter-chip phase difference to compensate for the chip phase offset, and the chip phase calibration between the first radar and the second radar is achieved in a soft way. Similarly, the actual phase difference and theoretical phase difference between the second radar and the third radar are calculated to obtain the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar. The ADC data of the third radar is moved in the time-frequency domain according to the second inter-chip phase difference to compensate for the chip phase offset, and the chip phase calibration between the second radar and the third radar is achieved in a soft way.

[0190] Step 5: Perform phase calibration on the raw ADC data of the first radar according to the first inter-chip phase difference; perform phase calibration on the raw ADC data of the third radar according to the second inter-chip phase difference.

[0191] Step 6: Calculate the vertical distance of the second target according to the ADC data after phase calibration between the first radar and the second radar; calculate the lateral distance of the second target according to the ADC data after phase calibration between the second radar and the third radar.

[0192] In a specific embodiment of the present invention, calculating the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar specifically includes:

[0193] Step 6.11: Process the ADC data after phase calibration of the first radar and the second radar (including FFT and constant false alarm rate detection) to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar;

[0194] Step 6.12: Based on the trigonometric function, the vertical distance of the second target is calculated according to the target distance and the target elevation angle monitored by the first radar and the second radar.

[0195] In a specific embodiment of the present invention, calculating the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar specifically includes:

[0196] Step 6.21: Process the ADC data after phase calibration of the second radar and the third radar (including FFT and constant false alarm rate detection) to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination;

[0197] Step 6.22: Based on the trigonometric function, calculate the lateral distance of the second target according to the target distance and target horizontal angle monitored by the second radar and the third radar.

[0198] Step 7: Calculate the vertical range of the protection area based on the target distance monitored by the radar group and the catenary equation of the overhead transmission line.

[0199] Overhead transmission lines are fixed and pulled by the iron towers at both ends. Therefore, the surface of the overhead transmission line is a catenary structure. The catenary equation is used to represent the surface of the overhead transmission line, as shown in formula (3).

[0200] The catenary equation can be used to obtain the entire overhead transmission line, which solves the problem that the radar cannot effectively detect the entire overhead transmission line. The radar only needs to accurately detect the longitudinal distance of the possible external damage target, and then calculate the height of the overhead transmission line corresponding to the current position of the external damage target according to formula (3).

[0201] The first radar, or the second radar, or the third radar, or the combination of the first radar and the second radar, or the combination of the second radar and the third radar can monitor the target distance. For example, the ADC data of the first radar and the second radar are subjected to FFT and constant false alarm rate detection to obtain the target distance monitored by the combination of the first radar and the second radar. The target distance is projected onto the Z axis, and the projection distance (i.e., the longitudinal distance of the target or the Z coordinate value of the target in the three-dimensional coordinate system) is used as the value in formula (3). z , the height of the overhead transmission line corresponding to the current position of the target can be calculated y . According to the height y The vertical range of the protection area can be re-determined by comparing the vertical range of the protection area with the vertical range of the overhead transmission line. For example, the vertical range of the protection area is y2-y1=40 meters, and the re-determined vertical range of the protection area is [y-20, y+20], which solves the problem that the radar cannot detect the entire overhead transmission line and realizes the accurate determination of the vertical range of the protection area.

[0202] Step 8: Determine again whether the target enters the protection area of ​​the overhead transmission line based on the second target vertical distance and the second target lateral distance.

[0203] According to the second target vertical distance and the second target lateral distance, it is judged again whether the target enters the protection area of ​​the overhead transmission line, and when it is judged again that the target enters the protection area of ​​the overhead transmission line, an early warning signal is issued. In a specific embodiment of the present invention, according to the second target vertical distance and the second target lateral distance, it is judged again whether the target enters the protection area of ​​the overhead transmission line, including:

[0204] When the lateral distance of the second target is within the lateral range of the protection area (for example, [x1, x2]), and the vertical distance of the second target is within the vertical range of the protection area (for example, [y-20, y+20]), the target enters the protection area of ​​the overhead transmission line, and the sound and light system and the remote system are linked to issue warnings and records.

[0205] Step 9: When it is determined again that the target enters the protection area of ​​the overhead transmission line, a warning signal is issued.

[0206] Example 3

[0207] An embodiment of the present invention further provides an electronic device, which includes: a memory, a processor, and a computer program / instruction stored in the memory, and the processor executes the computer program / instruction to implement the anti-destruction warning method in the embodiment of the present application.

[0208] Although not shown, the electronic device includes a processor that can perform various appropriate operations and processes according to the programs and / or data stored in the read-only memory (ROM) or the programs and / or data loaded from the storage part into the random access memory (RAM). The processor can be a multi-core processor or can include multiple processors. In some embodiments, the processor can include a general-purpose main processor and one or more special coprocessors, such as a central processing unit, a graphics processing unit (GPU), a neural network processor (NPU), a digital signal processor (DSP), etc. In RAM, various programs and data required for device operation are also stored. The processor, ROM, and RAM are connected to each other via a bus. The input / output (I / O) interface is also connected to the bus.

[0209] The processor and memory are used together to execute the program / instructions stored in the memory. When the program / instructions are executed by the computer, the methods, steps or functions described in the above embodiments can be implemented.

[0210] Although not shown, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the anti-damage warning method in the embodiment of the present application is implemented.

[0211] Readable storage media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0212] Although not shown, an embodiment of the present invention further provides a computer program product, including: a computer program / instruction, which implements the anti-damage warning method in the embodiment of the present application when executed by a processor.

[0213] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be covered within the protection scope of the present invention.

Claims

1. An anti-destruction warning system for overhead transmission lines, characterized in that: The system includes a radar group and a central processing unit. The radar group is arranged on an iron tower on one side of the overhead transmission line and is located below the overhead transmission line. The radar group includes a first radar, a second radar and a third radar. The first radar, the second radar and the third radar are respectively connected to the central processing unit. The first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line. The antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitting and multi-receiving antenna array and a vertical multi-transmitting and multi-receiving antenna array. The vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, and the radiation direction of the first radar, the second radar and the third radar points to the iron tower on the other side of the overhead transmission line. Each radar in the radar group is used to simultaneously radiate electromagnetic wave signals outward under the control of the central processor; sample the target reflected wave to obtain the original ADC data received by each channel of the corresponding radar, and send the original ADC data of each radar to the central processor; The central processing unit is used for: Sending a synchronous pulse signal to each radar in the radar group, so that each radar radiates electromagnetic wave signals outward at the same time; Based on the raw ADC data of the second radar, it is preliminarily determined whether the target has entered the protection area of ​​the overhead transmission line; When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, a first inter-chip phase difference caused by different clock sources between the first radar and the second radar and a second inter-chip phase difference caused by different clock sources between the second radar and the third radar are obtained, and the raw ADC data of the first radar is phase calibrated according to the first inter-chip phase difference; performing phase calibration on raw ADC data of the third radar according to the second inter-chip phase difference; Calculate the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar; calculate the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar; Calculate the vertical range of the protection area based on the target distance monitored by the radar group and the catenary equation of the overhead transmission line; Determining again whether the target has entered the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance; When it is determined again that the target has entered the protection area of ​​the overhead transmission line, an early warning signal is issued.

2. The anti-destruction warning system according to claim 1, characterized in that: The central processor is used to send a synchronous pulse signal to each radar in the radar group, specifically including: The central processor simultaneously sends a test pulse to each radar in the radar group; The central processor determines the transmission delay of the signal sent by the central processor to each radar in the radar group according to the time difference between each received feedback pulse; wherein each feedback pulse is a pulse sent by each radar in the radar group to the central processor after receiving the test pulse; The central processor sends a synchronization pulse signal to each radar in the radar group according to the transmission delay.

3. The anti-destruction warning system according to claim 1, characterized in that: The central processor is used to preliminarily determine whether the target enters the protection area of ​​the overhead transmission line according to the original ADC data of the second radar, specifically including: The original ADC data of the second radar is processed to obtain the target distance, target horizontal angle and target elevation angle monitored by the second radar; The lateral distance of the first target is calculated according to the target distance and the target horizontal angle monitored by the second radar, and the vertical distance of the first target is calculated according to the target distance and the target elevation angle monitored by the second radar; A preliminary judgment is made as to whether the target has entered the protection area of ​​the overhead transmission line based on the first target lateral distance and the first target vertical distance.

4. The anti-destruction warning system according to claim 1, characterized in that: The process of obtaining the first inter-chip phase difference and the second inter-chip phase difference is as follows: Setting a test target directly in front of the second radar; The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals to the test target simultaneously; Each radar in the radar group sends the received test echo signal to the central processor respectively; The central processing unit calculates the phase of each radar in the radar group for the same test target based on each test echo signal; The actual phase difference between the first radar and the second radar is calculated based on the phases of the first radar and the second radar for the same test target; the actual phase difference between the second radar and the third radar is calculated based on the phases of the second radar and the third radar for the same test target; The theoretical phase difference between the first radar and the second radar is calculated according to the distance between the first radar and the second radar, the installation height of the second radar, and the straight-line distance between the test target and the first radar and the second radar; the theoretical phase difference between the second radar and the third radar is calculated according to the distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar; The first inter-chip phase difference between the first radar and the second radar is calculated according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; the second inter-chip phase difference between the second radar and the third radar is calculated according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

5. The anti-destruction warning system according to claim 1, characterized in that: The central processor is used to calculate the vertical distance of the second target according to the ADC data after the phase calibration of the first radar and the second radar, specifically including: Processing the ADC data after phase calibration of the first radar and the second radar to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar; Calculate the vertical distance of the second target according to the target distance and the target elevation angle monitored by the first radar and the second radar; The central processor is used to calculate the lateral distance of the second target according to the ADC data after the phase calibration of the second radar and the third radar, specifically including: Processing the ADC data after phase calibration of the second radar and the third radar to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination; The lateral distance of the second target is calculated according to the target distance and the target horizontal angle monitored by the second radar and the third radar in combination.

6. The anti-destruction warning system according to any one of claims 1 to 5, characterized in that: The central processor is used to determine again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance, specifically including: When the second target lateral distance is within the lateral range of the protection area, and the second target vertical distance is within the vertical range of the protection area, the target enters the protection area of ​​the overhead transmission line.

7. A method for preventing damage to overhead power lines, characterized in that: A radar group is provided on one side tower of the overhead transmission line, the radar group is located below the overhead transmission line and includes a first radar, a second radar and a third radar; the first radar, the second radar and the third radar are respectively connected to a central processing unit; the first radar and the second radar are located on the same vertical line, and the second radar and the third radar are located on the same horizontal line; the antenna arrays of the first radar, the second radar and the third radar all include a horizontal multi-transmitting and multi-receiving antenna array and a vertical multi-transmitting and multi-receiving antenna array; the vertical line where the first radar and the second radar are located is consistent with the vertical direction of the overhead transmission line, the horizontal line where the second radar and the third radar are located is perpendicular to the overhead transmission line and its vertical direction, and the radiation direction of the first radar, the second radar and the third radar points to the other side tower of the overhead transmission line; the early warning method includes: The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals outward simultaneously; Each radar in the radar group sends the raw ADC data received by each channel thereof to the central processor; The central processor preliminarily determines whether the target has entered the protection area of ​​the overhead transmission line based on the raw ADC data of the second radar; When it is preliminarily determined that the target enters the protection area of ​​the overhead transmission line, the central processing unit obtains the first inter-chip phase difference caused by the different clock sources of the first radar and the second radar and the second inter-chip phase difference caused by the different clock sources of the second radar and the third radar, and performs phase calibration on the original ADC data of the first radar according to the first inter-chip phase difference; and performs phase calibration on the original ADC data of the third radar according to the second inter-chip phase difference; Calculate the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar; calculate the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar; Calculate the vertical range of the protection area based on the target distance monitored by the radar group and the catenary equation of the overhead transmission line; Determining again whether the target has entered the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance; When it is determined again that the target has entered the protection area of ​​the overhead transmission line, an early warning signal is issued.

8. The anti-destruction warning method according to claim 7, characterized in that: The central processor controls each radar in the radar group to radiate electromagnetic wave signals outward simultaneously, including: The central processor simultaneously sends a test pulse to each radar in the radar group; After receiving the test pulse, each radar in the radar group sends a feedback pulse to the central processor; The central processor determines the transmission delay of the signal sent by the central processor to each radar in the radar group according to the time difference between each received feedback pulse; The central processor sends a synchronization pulse signal to each radar in the radar group according to the transmission delay; Each radar in the radar group receives the synchronization pulse signal at the same time, and radiates electromagnetic wave signals outward at the same time under the triggering of the synchronization pulse signal.

9. The anti-destruction warning method according to claim 7, characterized in that: The central processor preliminarily determines whether the target has entered the protection area of ​​the overhead transmission line based on the raw ADC data of the second radar, including: The central processing unit processes the original ADC data of the second radar to obtain the target distance, target horizontal angle and target pitch angle monitored by the second radar; The lateral distance of the first target is calculated according to the target distance and the target horizontal angle monitored by the second radar, and the vertical distance of the first target is calculated according to the target distance and the target elevation angle monitored by the second radar; A preliminary judgment is made as to whether the target has entered the protection area of ​​the overhead transmission line based on the first target lateral distance and the first target vertical distance.

10. The anti-destruction warning method according to claim 7, characterized in that: The process of obtaining the first inter-chip phase difference and the second inter-chip phase difference is as follows: Setting a test target directly in front of the second radar; The central processing unit controls each radar in the radar group to radiate electromagnetic wave signals to the test target simultaneously; Each radar in the radar group sends the received test echo signal to the central processor respectively; The central processing unit calculates the phase of each radar in the radar group for the same test target based on each test echo signal; The actual phase difference between the first radar and the second radar is calculated based on the phases of the first radar and the second radar for the same test target; the actual phase difference between the second radar and the third radar is calculated based on the phases of the second radar and the third radar for the same test target; The theoretical phase difference between the first radar and the second radar is calculated according to the distance between the first radar and the second radar, the installation height of the second radar, and the straight-line distance between the test target and the first radar and the second radar; the theoretical phase difference between the second radar and the third radar is calculated according to the distance between the second radar and the third radar, the installation height of the second radar, and the straight-line distance between the test target and the second radar and the third radar; The first inter-chip phase difference between the first radar and the second radar is calculated according to the actual phase difference and the theoretical phase difference between the first radar and the second radar; the second inter-chip phase difference between the second radar and the third radar is calculated according to the actual phase difference and the theoretical phase difference between the second radar and the third radar.

11. The anti-destruction warning method according to claim 7, characterized in that: Calculating the vertical distance of the second target according to the ADC data after phase calibration of the first radar and the second radar includes: Processing the ADC data after phase calibration of the first radar and the second radar to obtain the target distance and target elevation angle monitored by the combination of the first radar and the second radar; Calculate the vertical distance of the second target according to the target distance and the target elevation angle monitored by the first radar and the second radar; Calculating the lateral distance of the second target according to the ADC data after phase calibration of the second radar and the third radar, including: Processing the ADC data after phase calibration of the second radar and the third radar to obtain the target distance and target horizontal angle monitored by the second radar and the third radar combination; The lateral distance of the second target is calculated according to the target distance and the target horizontal angle monitored by the second radar and the third radar in combination.

12. The anti-destruction warning method according to claim 7, characterized in that: The catenary equation of the overhead transmission line is: y = acosh(z / a); Among them, y represents the height of a point on the overhead transmission line; z represents the distance between a point on the overhead transmission line and the starting point of the overhead transmission line; a represents a constant; and cosh represents the hyperbolic cosine function.

13. The anti-destruction warning method according to any one of claims 7 to 12, characterized in that: Judging again whether the target enters the protection area of ​​the overhead transmission line according to the second target vertical distance and the second target lateral distance includes: When the second target lateral distance is within the lateral range of the protection area, and the second target vertical distance is within the vertical range of the protection area, the target enters the protection area of ​​the overhead transmission line.

14. An electronic device comprising a memory, a processor, and a computer program / instruction stored in the memory, characterized in that: The processor executes the computer program / instructions to implement the anti-damage warning method as described in any one of claims 7 to 13.

15. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the anti-destruction warning method as described in any one of claims 7 to 13 is implemented.

16. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the anti-destruction warning method as described in any one of claims 7 to 13 is implemented.

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