CN113820709B - Through-wall radar detection system and detection method based on unmanned aerial vehicle - Google Patents

Abstract

The invention discloses a through-wall radar detection system and a detection method based on an unmanned aerial vehicle, wherein the system comprises the unmanned aerial vehicle, an environment sensing unit, a through-wall radar, a holder and a control unit; the unmanned aerial vehicle, the environment sensing unit, the through-wall radar and the holder are all connected with the control unit; the through-wall radar is positioned on the unmanned aerial vehicle and used for detecting the external structure, the internal structure and the internal personnel of the building to be detected; the environment sensing unit is positioned on the unmanned aerial vehicle and used for sensing the flight environment information of the unmanned aerial vehicle and sending the flight environment information to the control unit; the control unit controls the flight of the unmanned aerial vehicle according to the flight environment information so as to keep the distance between the unmanned aerial vehicle and the outer wall body within a certain range; the cloud platform is located unmanned aerial vehicle, and the receiving and dispatching antenna of through-wall radar is located the cloud platform, and the control unit is according to flight environment information control cloud platform's action so that the array face of receiving and dispatching antenna keeps parallel with outer wall body. The invention has the advantages of simple structure, good detection performance and the like.

Description

Through-wall radar detection system and detection method based on unmanned aerial vehicle

Technical Field

The invention mainly relates to the technical field of radar detection, in particular to a through-wall radar detection system and a detection method based on an unmanned aerial vehicle.

Background

The through-wall radar is a technology for detecting a target behind a wall, which is rapidly developed in recent years, and can detect, image, locate, track, identify and the like the target behind the wall, so that the through-wall radar has wide application in the aspects of urban street fighting, anti-terrorism security, disasters and hostage rescue.

The traditional through-wall radar is based on detection by wall-attached equipment, and the short-distance detection is very dangerous in practical application. Therefore, a long-distance through-wall radar research based on unmanned aerial vehicles needs to be developed. In a drone-based through-wall radar, the drone either hovers at a fixed point or is set to move along a straight line parallel to the wall to detect. However, in a real situation, for example, when the unmanned aerial vehicle suspends, the hovering precision cannot be guaranteed, so that the radar shakes back and forth, the detection performance is reduced, and even a target cannot be detected; unmanned aerial vehicle position also often all is non-rectilinear when parallel motion, can bring very big puzzlement for through-the-wall radar signal processing equally, causes the detection performance to descend.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the problems in the prior art, the invention provides a through-wall radar detection system and a detection method based on an unmanned aerial vehicle, which have good detection performance.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a through-wall radar detection system based on an unmanned aerial vehicle comprises the unmanned aerial vehicle, an environment sensing unit, a through-wall radar, a holder and a control unit;

the unmanned aerial vehicle, the environment sensing unit, the through-wall radar and the holder are all connected with the control unit;

the through-wall radar is positioned on the unmanned aerial vehicle and used for detecting the external structure, the internal structure and the internal personnel of the building to be detected;

the environment sensing unit is positioned on the unmanned aerial vehicle and used for sensing the flight environment information of the unmanned aerial vehicle and sending the flight environment information to the control unit; the flight environment information comprises distance information between the unmanned aerial vehicle and an outer wall of the building to be tested;

the control unit controls the flight of the unmanned aerial vehicle according to the flight environment information so as to keep the distance between the unmanned aerial vehicle and the outer wall body within a certain range;

the cloud platform is located on the unmanned aerial vehicle, the receiving and transmitting antenna of the through-wall radar is located on the cloud platform, and the control unit controls the action of the cloud platform according to the flight environment information so that the array surface of the receiving and transmitting antenna is parallel to the outer wall body.

As a further improvement of the above technical solution:

the environment perception unit comprises a vision module and a ranging radar module, the vision module is used for detecting visual information of the unmanned aerial vehicle, and the ranging radar module is used for detecting the distance between the unmanned aerial vehicle and the outer wall body.

The range radar module is a laser radar.

The vision module is a camera.

The ground station is in communication connection with the control unit.

The invention also discloses a detection method based on the through-wall radar detection system based on the unmanned aerial vehicle, which comprises the following steps:

the environment sensing unit senses the flight environment information of the unmanned aerial vehicle and sends the flight environment information to the control unit; the flight environment information comprises distance information between the unmanned aerial vehicle and an outer wall of the building to be tested;

the control unit controls the flight of the unmanned aerial vehicle according to the flight environment information so as to keep the distance between the unmanned aerial vehicle and the outer wall body within a certain range, and controls the action of the holder so as to keep the array surface of the receiving and transmitting antenna parallel to the outer wall body;

the through-wall radar detects the external structure, the internal structure and the internal personnel of the building to be detected.

As a further improvement of the above technical solution:

the detection includes fixed point detection and surround flight detection.

The control unit controls the action of the cradle head so that the array surface of the transmitting and receiving antenna is parallel to the outer wall body, and the specific process comprises the following steps:

the environment sensing unit starts working, building point cloud data are obtained, a point cloud normal is extracted, and plane information is extracted by clustering the point cloud normal; the method comprises the steps of selecting a plane with the largest data quantity from a plurality of plane information to be subjected to normal angle extraction, obtaining attitude information of an environment sensing unit relative to a wall body, transmitting the attitude information to a cloud deck, calculating the attitude angle of the cloud deck according to the obtained data information, achieving the required control angle through an external control motor, achieving the function of locking the wall body, and achieving the parallelism of a front surface of a transmitting-receiving antenna and the wall body.

Compared with the prior art, the invention has the advantages that:

according to the through-wall radar detection system based on the unmanned aerial vehicle, flight environment information such as the distance between the unmanned aerial vehicle and a wall body is acquired through the environment sensing unit, on the basis of realizing conventional obstacle avoidance of the unmanned aerial vehicle, the distance between the unmanned aerial vehicle and an outer wall body is kept within a certain range, and the through-wall radar can conveniently detect a building to be detected; in addition, the receiving and transmitting antenna of the through-wall radar is positioned on the three-axis stabilizing pan-tilt, so that on one hand, the stability and the precision of the receiving and transmitting antenna can be guaranteed (the stability of the antenna cannot be influenced if the unmanned aerial vehicle shakes), and on the other hand, the action of the three-axis stabilizing pan-tilt can be controlled according to the flight environment information, so that the array surface of the receiving and transmitting antenna is parallel to the outer wall body, and the detection performance of the through-wall radar is guaranteed; in addition, the action of the three-axis stable holder can also realize the detection in all directions such as the side detection and the up-and-down detection of the through-wall radar.

Drawings

FIG. 1 is a block diagram of an embodiment of the system of the present invention.

Fig. 2 is a diagram of an embodiment of the system of the present invention in a specific application.

Illustration of the drawings: 1. an unmanned aerial vehicle; 2. an environment sensing unit; 3. a through-wall radar; 4. a holder; 5. a ground station; 6. a control unit.

Detailed Description

The invention is further described below with reference to the figures and the specific embodiments of the description.

As shown in fig. 1 and fig. 2, the through-wall radar detection system based on the unmanned aerial vehicle in the embodiment of the present invention includes an unmannedaerial vehicle 1, anenvironment sensing unit 2, a through-wall radar 3, a three-axis stabilization pan-tilt 4, and a control unit 6 (in the embodiment, the control unit 6 is preferably a flight control system of the unmanned aerial vehicle 1); the unmannedaerial vehicle 1, theenvironment sensing unit 2, the through-wall radar 3 and the three-axis stabilizing pan-tilt 4 are all connected with the control unit 6; the through-wall radar 3 is positioned on the unmannedaerial vehicle 1 and used for detecting the external structure, the internal structure and the internal personnel of the building to be detected; theenvironment sensing unit 2 is positioned on the unmannedaerial vehicle 1 and used for sensing the flight environment information of the unmannedaerial vehicle 1 and sending the flight environment information to the control unit 6; the flight environment information comprises distance information between the unmannedaerial vehicle 1 and an outer wall of a building to be tested; the control unit 6 controls the flight of the unmannedaerial vehicle 1 according to the flight environment information so as to keep the distance between the unmannedaerial vehicle 1 and the outer wall body within a certain range; the triaxial stabilizing pan-tilt 4 is positioned on the unmannedaerial vehicle 1, the receiving and transmitting antenna of the through-wall radar 3 is positioned on the triaxial stabilizing pan-tilt 4, and the control unit 6 controls the action of the triaxial stabilizing pan-tilt 4 according to the flight environment information so that the array surface of the receiving and transmitting antenna is parallel to the outer wall body.

According to the through-wall radar detection system based on the unmanned aerial vehicle, flight environment information such as the distance between the unmannedaerial vehicle 1 and a wall body is acquired through theenvironment sensing unit 2, on the basis of realizing conventional obstacle avoidance of the unmannedaerial vehicle 1, the distance between the unmannedaerial vehicle 1 and an outer wall body is guaranteed to be kept within a certain range, and detection of a building to be detected by the through-wall radar 3 is facilitated; namely, the distance between the unmannedaerial vehicle 1 and the wall body is stable, so that the unmannedaerial vehicle 1 can be in a static state relative to the wall body through a motion compensation algorithm, and the cancellation processing of a radar signal and the detection of a micro Doppler target are facilitated;

in addition, a receiving and transmitting antenna of the through-wall radar 3 is positioned on the three-axis stable tripod head 4, on one hand, the stability and the precision of the receiving and transmitting antenna can be guaranteed (if the unmannedaerial vehicle 1 shakes, the stability of the antenna cannot be influenced), namely, the attitude information (including shaking information) of the unmannedaerial vehicle 1 acquired by theenvironment sensing unit 2 and an IMU (inertial measurement unit) unit of the unmannedaerial vehicle 1 can be transmitted to the control unit 6 in real time, the control unit 6 carries out negative feedback on the shaking of the unmannedaerial vehicle 1 in real time, the tripod head reaches an angle to be controlled by using an external control motor, the shaking of the unmannedaerial vehicle 1 is compensated, and the receiving and transmitting antenna on the unmannedaerial vehicle 1 is kept relatively stable;

on the other hand, the action of the three-axis stabilizing pan-tilt 4 can be controlled according to the flight environment information, so that the array surface of the transmitting and receiving antenna is kept parallel to the outer wall body, and the detection performance of the through-wall radar 3 is guaranteed; specifically, theenvironment sensing unit 2 obtains point cloud data around the unmannedaerial vehicle 1, firstly, a data point cloud normal is extracted in real time according to the point cloud data, plane information is extracted through point cloud normal clustering, then, a plurality of planes are utilized, the plane with the largest data volume is selected from the planes, and normal angle extraction is carried out, so that attitude information of theenvironment sensing unit 2 relative to a wall surface can be obtained, finally, the attitude information is transmitted to a holder 4 for control, the relative position is controlled to achieve the function of locking the wall surface, the parallel of a transmitting-receiving antenna and the wall body is realized, after the wall body is kept parallel, the maximum direction of electromagnetic waves radiated by a radar can be kept consistent with a target, so that the radar energy obtained at the target is the highest, and the detection capability of the radar is stronger;

in addition, the action of the three-axis stable holder 4 can realize the detection in all directions such as the side detection and the vertical detection of the through-wall radar 3, and the multiple working modes of the complex environment are compatible.

In a specific embodiment, theenvironmental sensing unit 2 includes a vision module (e.g., a camera) for detecting the visual information of the unmannedaerial vehicle 1 and a ranging radar module (e.g., a laser radar) for detecting the distance between the unmannedaerial vehicle 1 and the outer wall; anenvironment sensing unit 2 is formed between the camera and the laser radar, and the structure is simple.

In a specific embodiment, the unmannedaerial vehicle 1 is mainly responsible for carrying a camera, a laser radar, a three-axis stabilization pan-tilt 4 and a through-wall radar 3, and functions of hovering positioning, flight path flight, automatic landing and the like are realized. In addition, the unmannedaerial vehicle 1 comprises a plurality of communication units, and communication control between theground station 5 and the unmannedaerial vehicle 1 is mainly realized, including transmission of data such as the working mode of the through-wall radar 3, the final target result and the real-time position of the holder 4.

The environment sensingunit 2 detects and reconstructs a forward-looking visual target, and obtains barrier information of the unmannedaerial vehicle 1 in all directions in real time, including position and shape characteristics and the like, so that the unmannedaerial vehicle 1 can automatically avoid barriers. Wherein camera and lidar ride on unmannedaerial vehicle 1. Of course, in other embodiments, the camera and the lidar may also be mounted on the head 4 (within the weight-bearing range of the head 4).

For the flight platform, the detection performance of the through-wall radar 3 is only related to the position of the transmitting and receiving antenna, the position of the transmitting and receiving antenna is relatively stable, and even if the platform of the unmannedaerial vehicle 1 shakes seriously, the detection performance cannot be greatly influenced. The relative stability of the antenna position can be ensured by mounting the receiving and transmitting antenna on the three-axis stable holder 4; through the flight of unmannedaerial vehicle 1 and the cooperation between the stable cloud platform 4 of triaxial again, guarantee the distance between the receiving and dispatching antenna array face of penetratingwall radar 3 and the wall body and the position isoparametric to guarantee that receiving and dispatching antenna array face is parallel with the wall body barrier, greatly guarantee the detection performance of system.

The through-wall radar 3 mainly realizes the detection of the inner and outer structures of the building and the detection of the personnel in the building, and realizes the positioning of the structures and the personnel in the building. Specifically including receiving and dispatching antenna, transmitter, receiver and signal processing unit, signal processing unit places on unmannedaerial vehicle 1 fuselage, and only places receiving and dispatching antenna in on cloud platform 4 to reduce the stable cloud platform 4 loads of triaxial, improve cloud platform 4 action response speed, realize quick adjustment and aim at.

Theground station 5 mainly completes the control of the unmannedaerial vehicle 1, the display of the data of the laser radar and the through-wall radar 3 and the issuing of the instruction, and belongs to the medium of the interaction of the laser radar, the through-wall radar 3 and the unmannedaerial vehicle 1 with the user.

The embodiment of the invention also discloses a detection method based on the through-wall radar detection system based on the unmanned aerial vehicle, which comprises the following steps:

theenvironment sensing unit 2 senses the flight environment information of the unmannedaerial vehicle 1 and sends the flight environment information to the control unit 6; the flight environment information comprises distance information between the unmannedaerial vehicle 1 and an outer wall of a building to be tested;

the control unit 6 controls the flight of the unmannedaerial vehicle 1 according to the flight environment information so as to keep the distance between the unmannedaerial vehicle 1 and the outer wall body within a certain range, and controls the action of the three-axis stable holder 4 so as to keep the array surface of the receiving and transmitting antenna parallel to the outer wall body;

the through-wall radar 3 detects the external structure, the internal structure and the internal personnel of the building to be detected.

In a specific embodiment, the specific process of controlling the motion of the three-axis stabilized pan/tilt head 4 by the control unit 6 to keep the front surface of the transmitting/receiving antenna parallel to the outer wall body is as follows:

theenvironment sensing unit 2 starts working, building point cloud data are obtained, a point cloud normal is extracted, and plane information is extracted by clustering the point cloud normal; the method comprises the steps of selecting a plane with the largest data volume from a plurality of plane information to be subjected to normal angle extraction, obtaining attitude information of theenvironment sensing unit 2 relative to a wall body, transmitting the attitude information to the three-axis stabilizing pan-tilt 4, calculating the attitude angle of the three-axis stabilizing pan-tilt 4 according to the obtained data information, achieving the required control angle through an external control motor, achieving the function of locking the wall body, and achieving the parallel of a receiving and transmitting antenna array surface and the wall body.

The workflow of the present invention is further described in detail with reference to a complete embodiment:

firstly, a through-wall radar 3, a camera, a laser radar and a three-axis stabilizing pan-tilt 4 are installed on an unmannedaerial vehicle 1, all the devices are powered by the unmannedaerial vehicle 1, and device data are transmitted to aground station 5 through a data transmission communication system;

after an operator of theground station 5 starts to execute the fixed-point detection task requirement, the unmannedaerial vehicle 1 hovers at a certain position as required after taking off, the camera and the laser radar detect the position of the front wall in real time, and the position of the unmannedaerial vehicle 1 is adjusted according to the distance required by obstacle avoidance; after the unmannedaerial vehicle 1 hovers, the position of the cloud deck 4 is adjusted according to the information transmitted by the camera and the laser radar, the array surface of the receiving and transmitting antenna is ensured to be parallel to the wall, and the position of the array surface of the receiving and transmitting antenna and the position of the wall are ensured to be a set fixed value, such as 5 m;

after that, the through-wall radar 3 starts to perform fixed-point detection on personnel in the building, and when a target is detected, the through-wall radar 3 transmits the target to theground station 5 through the data transmission communication system and displays the target; where spot detection can show local building structures and personnel objects.

When the requirement of a surrounding flight detection task is started to be executed, the unmannedaerial vehicle 1 takes off and flies around a building according to a preset air route, meanwhile, the laser radar can acquire the position of a front obstacle in the transverse movement in advance and rebuild the obstacle, and when the unmannedaerial vehicle 1 flies, the antenna array surface and the obstacle are always kept parallel;

then the through-wall radar 3 starts to detect the internal and external structures of the building, synchronously detects personnel in the building, and transmits and displays the obtained personnel targets and the building structure to theground station 5 through a data transmission communication system;

after completing a flight path flight and target detection, the unmannedaerial vehicle 1 will automatically land or execute the next flight detection task.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.

Claims (7)

1. A through-wall radar detection system based on an unmanned aerial vehicle is characterized by comprising the unmanned aerial vehicle (1), an environment sensing unit (2), a through-wall radar (3), a cloud deck (4) and a control unit (6);

the unmanned aerial vehicle (1), the environment sensing unit (2), the through-wall radar (3) and the cradle head (4) are all connected with the control unit (6);

the through-wall radar (3) is positioned on the unmanned aerial vehicle (1) and is used for detecting the external structure, the internal structure and the internal personnel of the building to be detected;

the environment sensing unit (2) is positioned on the unmanned aerial vehicle (1) and used for sensing the flight environment information of the unmanned aerial vehicle (1) and sending the flight environment information to the control unit (6); the flight environment information comprises distance information between the unmanned aerial vehicle (1) and an outer wall of a building to be tested;

the control unit (6) controls the flight of the unmanned aerial vehicle (1) according to the flight environment information so as to keep the distance between the unmanned aerial vehicle (1) and the outer wall body within a certain range;

the cloud deck (4) is positioned on the unmanned aerial vehicle (1), the transmitting and receiving antenna of the through-wall radar (3) is positioned on the cloud deck (4), and the control unit (6) controls the action of the cloud deck (4) according to the flight environment information so that the array surface of the transmitting and receiving antenna is parallel to the outer wall body;

the environment sensing unit (2) comprises a vision module and a ranging radar module, the vision module is used for detecting the vision information of the unmanned aerial vehicle (1), and the ranging radar module is used for detecting the distance between the unmanned aerial vehicle (1) and the outer wall body;

the environment sensing unit (2) is used for acquiring point cloud data around the unmanned aerial vehicle (1), extracting a data point cloud normal in real time according to the point cloud data, clustering the point cloud normal to extract plane information, then utilizing a plurality of planes, selecting the plane with the largest data volume from the planes to perform normal angle extraction, thereby acquiring attitude information of the environment sensing unit (2) relative to a wall surface, finally utilizing the attitude information to transmit to the holder (4) for control, controlling to the relative position to achieve the function of locking the wall surface, and realizing the parallelism of a transmitting-receiving antenna and a wall body.

2. The unmanned-aerial-vehicle-based through-wall radar detection system of claim 1, wherein the range radar module is a lidar.

3. The drone-based through-wall radar detection system of claim 1 or 2, wherein the vision module is a camera.

4. The unmanned-aerial-vehicle-based through-wall radar detection system of claim 1 or 2, further comprising a ground station (5), wherein the ground station (5) is communicatively connected to the control unit (6).

5. A detection method based on the unmanned aerial vehicle-based through-wall radar detection system of any one of claims 1-4, characterized by comprising the following steps:

the environment sensing unit (2) senses the flight environment information of the unmanned aerial vehicle (1) and sends the flight environment information to the control unit (6); the flight environment information comprises distance information between the unmanned aerial vehicle (1) and an outer wall of a building to be tested;

the control unit (6) controls the flight of the unmanned aerial vehicle (1) according to the flight environment information so as to keep the distance between the unmanned aerial vehicle (1) and the outer wall body within a certain range, and controls the action of the cradle head (4) so as to keep the array surface of the receiving and transmitting antenna parallel to the outer wall body;

the through-wall radar (3) is used for detecting the external structure, the internal structure and the internal personnel of the building to be detected.

6. The detection method according to claim 5, wherein the detection comprises fixed point detection and surround flight detection.

7. The detection method according to claim 6, wherein the specific process of controlling the action of the pan/tilt head (4) by the control unit (6) to keep the wavefront of the transmitting/receiving antenna parallel to the outer wall body is as follows:

the environment sensing unit (2) starts working, building point cloud data are obtained, a point cloud normal is extracted, and plane information is extracted by clustering the point cloud normal; the method comprises the steps of selecting a plane with the largest data quantity from a plurality of plane information to be subjected to normal angle extraction, obtaining attitude information of the environment sensing unit (2) relative to a wall body, transmitting the attitude information to the cloud deck (4), calculating the attitude angle of the cloud deck (4) according to the obtained data information, achieving the required control angle through an external control motor, achieving the function of locking the wall body, and achieving the parallel of a receiving and transmitting antenna array surface and the wall body.

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