CN106199572A - Low slow Small object solid speed detection method and system based on sound intensity detection - Google Patents

Abstract

The invention discloses a kind of low slow Small object solid speed detection method and system based on sound intensity detection, said method includes: in target flight region arranged beneath no less than 4 probe units, above-mentioned probe unit is distributed in mutually perpendicular two planes, and each plane is including at least 3 probe units.When target approaches, each probe unit obtain with target closest to time moment, as the zero crossing moment.The zero crossing moment obtained according to each probe unit calculates the target projection speed in above-mentioned two plane.The low slow Small object solid speed detection method and system based on sound intensity detection that the present invention provides are simple and easy to do, with low cost, detection accuracy is high, be suitable to spread in engineer applied.

Description

Low-slow small target three-dimensional speed detection method and system based on sound intensity detection

Technical Field

The invention relates to the technical field of sensing, in particular to a low-speed small target three-dimensional speed detection method and system based on sound intensity detection.

Background

The low-slow small target is short for low-altitude low-speed small target, and means that the flying height is below 1km, the flying speed is less than 200km, and the radar reflection area is less than 2m²Various small aircraft or air floats. The prior art is difficult to realize all-weather effective detection and monitoring of low and slow small targets by using a single detection means. The detection of low-slow small targets is a typical complex information system and is a technical problem in the international scope at present. With the opening of low-altitude airspace in China, the supervision and prevention of low and slow small targets become problems to be solved urgently, so that the method has important significance for detecting and intercepting the low and slow small targets, and the detection is a precondition for intercepting the low and slow small targets.

Although the traditional target detection method is relatively perfect, the low-speed small target has the characteristics of low flying height, low moving speed, weak scattering intensity and the like, which brings great difficulty to target detection. Under the strong constraint condition, how to construct an effective detection system and realize accurate detection of low-speed and small targets has great difficulty. The existing low-slow small target detection is mainly based on an infrared optical sensor or a radar, and the method has the advantages of higher cost, limited precision and difficulty in large-area popularization and application.

Therefore, a low-speed small-target stereo velocity detection method and system with low cost, high detection accuracy and strong engineering applicability are needed to solve the above problems.

Disclosure of Invention

The method and the system for detecting the stereo speed of the low-speed small target based on the sound intensity detection are simple, convenient and feasible, low in cost, high in detection precision and suitable for large-area popularization in engineering application.

The invention provides a low-slow small target three-dimensional speed detection method based on sound intensity detection, which comprises the following steps: s1, at least 4 detection units are arranged below a target flight area, the detection units are distributed on two planes which are perpendicular to each other, and each plane at least comprises 3 detection units; s2, when the target approaches, each detection unit acquires the time closest to the target as the zero crossing point time; and S3, calculating the projection speeds of the target on the two planes according to the zero-crossing point moment acquired by each detection unit.

Preferably, the not less than 4 detection units are specifically 6 detection units; the 6 detection units are distributed on a first plane and a second plane which are perpendicular to each other; the first plane comprises a first detection unit, a second detection unit, a third detection unit and a fourth detection unit which form a first quadrangle in the 6 detection units, and the second plane comprises a third detection unit, a fourth detection unit, a fifth detection unit and a sixth detection unit which form a second quadrangle in the 6 detection units; the first detection unit and the fourth detection unit are located at diagonal positions of the first quadrangle, and the third detection unit and the sixth detection unit are located at diagonal positions of the second quadrangle.

Preferably, the first quadrangle and the second quadrangle are squares with equal sides.

Preferably, step S3 is specifically: calculating the projection speeds of the target on the first plane and the second plane by using a formula 1 and a formula 2 according to the zero crossing point time acquired by each detection unit;

wherein v is_xoyIs the projection velocity, v, of the object on the first plane_xozIs the projection velocity of the object on the second plane, t₁、t₂、t₃、t₄、t₅、t₆The zero-crossing time points obtained by the first detection unit, the second detection unit, the third detection unit, the fourth detection unit, the fifth detection unit and the sixth detection unit are respectively, and l is the side length of the first quadrangle.

Preferably, the detection unit is a sound sensor.

Preferably, the method further comprises: and taking the moment when the noise amplitude acquired by the sound sensor is maximum as the zero crossing point moment.

Preferably, the noise frequency acquired by the sound sensor before the zero-crossing point time is greater than the noise frequency acquired by the sound sensor after the zero-crossing point time.

In another aspect, the present invention provides a stereo velocity detection system for low and slow small targets based on sound intensity detection, comprising:

the detection module comprises not less than 4 sound sensors and is arranged on two planes which are perpendicular to each other below a target flight area, and each plane of the two planes at least comprises 3 sound sensors; the sound sensor is used for acquiring the moment when the noise amplitude is maximum as the zero crossing point moment when the target approaches;

and the speed calculation module is used for calculating the projection speeds of the target on the two planes according to the zero-crossing point moment acquired by each sound sensor.

Preferably, the detection module comprises 6 sound sensors distributed on a first plane and a second plane which are perpendicular to each other; the first sound sensor, the second sound sensor, the third sound sensor and the fourth sound sensor are distributed on the first plane to form a first square; the third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are distributed on the second plane to form a second square with the same side length as the first square; the first sound sensor and the fourth sound sensor are located at the diagonal position of the first square, and the third sound sensor and the sixth sound sensor are located at the diagonal position of the second square.

Preferably, the calculating the projection speeds of the target on the two planes according to the zero-crossing point time acquired by each sound sensor specifically includes: calculating the projection speeds of the target on the first plane and the second plane by using a formula 4 and a formula 5 according to the zero crossing point time acquired by each sound sensor;

wherein v is_xoyIs the projection velocity, v, of the object on the first plane_xozIs the projection velocity, T, of the object in the second plane₁、T₂、T₃、T₄、T₅、T₆The zero-crossing time points obtained by the first sound sensor, the second sound sensor, the third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are respectively, and l is the side length of the first square.

According to the technical scheme, the method can realize the accurate detection of the three-dimensional speed of the low-speed small target by adopting a small number of detection units, has the advantages of simple principle, easy realization and low cost, is suitable for large-area popularization in engineering application, and successfully solves the problem of low-speed small target detection puzzling the field for many years.

Drawings

FIG. 1 is a schematic diagram of a low-slow small-target stereo velocity detection method of the present invention;

FIG. 2 is a schematic diagram of a detection unit arrangement according to an embodiment of the present invention;

FIG. 3 is a first schematic of projection velocity calculation according to an embodiment of the present invention;

FIG. 4 is a schematic view of a low-slow small-target stereo velocity detection system of the present invention;

FIG. 5 is a second schematic of projection velocity calculation according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings by way of examples of preferred embodiments. It should be noted, however, that the numerous details set forth in the description are merely for the purpose of providing the reader with a thorough understanding of one or more aspects of the present invention, which may be practiced without these specific details.

The inventor of the invention considers that although the traditional target detection method is relatively perfect, the method for considering both precision and cost is difficult to provide for small low-speed targets with the characteristics of low flying height, low moving speed, weak scattering intensity and the like. Specifically, the existing low-slow small target detection is mainly based on an infrared optical sensor and a radar, and has the advantages of higher cost, limited precision and difficulty in large-area popularization and use.

In view of the above, the inventors of the present invention creatively adopt a small number of detection units to obtain the closest point time of the target and the detection unit, and obtain the projection speed of the target track on the sensor plane by using the position difference of a plurality of detection units and the respective closest point time, thereby obtaining the stereo speed of the target track. The invention can realize the accurate detection of the three-dimensional speed of the low-speed small target, has lower cost and easy realization, and is suitable for large-area popularization in engineering application.

Fig. 1 shows a stereo velocity detection method of a low-slow small target based on sound intensity detection, referring to fig. 1, the method is performed according to the following steps:

first, in step S1, at least 4 detecting units are arranged below the target flight area, the detecting units being distributed in two planes perpendicular to each other, each of which contains at least 3 detecting units.

Thereafter, in step S2, when the target approaches, each detection unit acquires the time when it is closest to the target as the zero-crossing point time.

Next, in step S3, the projection velocities of the object on the two planes are calculated according to the zero-crossing point time acquired by each detection unit, and the stereo velocity of the object is obtained.

According to the steps, the method can complete the detection of the three-dimensional speed of the low-speed small target by adopting at least 4 detection units. The specific process of calculating the projection velocity using 4 detection units is shown in fig. 5:

the 4 detecting units are distributed in two planes, and each plane comprises 3 detecting units. Referring to fig. 5, 1, 2, and 3 in the figure are the geometric centers of three detecting units located in any one of the two planes; NM is the projection of the target flight trajectory on the plane; n is a radical of₁、N₂、N₃The projection on the NM of 1, 2, 3, respectively, i.e. the closest point of 1, 2, 3 to the NM. 1. 3, the connecting line and the NM form an included angle theta; 1. 2, 3 form a triangle: 1. the side length between 2 is a, the side length between 2 and 3 is b, the side length between 1 and 3 is c, and the internal angle of 3 is theta₀。

According to the specific application environment, it can be reasonably assumed that the flight path of the target is parallel or nearly parallel to the plane, and the projection speed of the target on the plane is set as v₀The zero-crossing points acquired by the detection units 1, 2 and 3 are t₀₁、t₀₂、t₀₃And (3) easy to know:

solving the formula 3 to obtain the projection speed of the target on the planeDegree v₀Then, the projection speed of the target on another plane can be obtained by the same method, and finally the stereo speed of the target is obtained.

The above calculation does not consider the case of 1, 2, and 3 being collinear, but this case is similar to the above calculation process, and therefore is not described in detail.

In practical applications, the calculation process of the above method is complicated, and therefore, in the preferred embodiment of the present invention, 6 detection units are adopted for detection.

Fig. 2 shows the distribution of the above-mentioned 6 detecting units, and referring to fig. 2, the 6 detecting units are distributed on a first plane xoy and a second plane xoz perpendicular to each other. The first plane xoy includes a first detecting unit 11, a second detecting unit 12, a third detecting unit 13, and a fourth detecting unit 14, which form a first quadrangle. The second plane xoz includes a third detecting unit 13, a fourth detecting unit 14, a fifth detecting unit 15 and a sixth detecting unit 16, which form a second quadrangle. The first detecting unit 11 and the fourth detecting unit 14 are located at diagonal positions of the first quadrangle, the second detecting unit 12 and the third detecting unit 13 are located at diagonal positions of the first quadrangle, the third detecting unit 13 and the sixth detecting unit 16 are located at diagonal positions of the second quadrangle, and the fourth detecting unit 14 and the fifth detecting unit 15 are located at diagonal positions of the second quadrangle.

Obviously, the design can obtain the stereo velocity of the target in a manner similar to equation 3, and the specific calculation process is not described herein again.

Preferably, in order to reduce the cost, the detection unit is provided as a sound sensor with lower cost.

The working principle of the sound detector is as follows: when flying, the aerial target radiates noise outwards due to the reasons of engine operation, friction between a machine body and air, interaction between jet flow and air, air beating by blades and the like, and the sound spectrum characteristic of the small-sized flying target is mainly concentrated on 100-1000 Hz. When the small flying target approaches the sound sensor, the noise signal intensity is increased; when the small flying target is closest to the sound sensor, the noise signal intensity reaches the maximum; when the small flying target is far away from the sound sensor, the noise signal intensity becomes small. Meanwhile, when the small flying target is close to or far away from the sound sensor, the noise spectrum generates frequency deviation due to the Doppler effect. Therefore, the time of the small flying target from the nearest point of the sound sensor can be obtained through the strength and frequency deviation condition of the noise signal received by the sound sensor, and the time is characterized in that: the noise amplitude of the frequency band of 100-1000 Hz is a peak value, and the noise frequency of the moment in front of the peak value is higher than the noise frequency of the moment behind the peak value. Therefore, when the plurality of sound sensors are arranged at different positions in space, a plurality of zero-crossing points can be obtained, and the projection speed of the target flight trajectory can be calculated by using the zero-crossing points.

In view of the above, in practical applications, the present invention takes the time when the noise amplitude acquired by the acoustic sensor is maximum as the zero-crossing point time. Preferably, the time when the noise amplitude of the frequency band of 100-1000 Hz is maximum is taken as the zero crossing point time. Meanwhile, in a preferred embodiment of the present invention, the noise frequency acquired by the acoustic sensor before the zero-crossing point time is greater than the noise frequency acquired by the acoustic sensor after the zero-crossing point time. Therefore, more accurate extraction of the zero crossing point moment is realized.

The quadrangle in the above calculation method is arbitrarily set, and still does not contribute to the simplification of the calculation. Therefore, in practical application, the first quadrangle and the second quadrangle are set to be squares with the side length of l to simplify the operation and improve the detection precision. The arrangement of 6 sensors is shown in fig. 2, taking the center of the first quadrangle as the origin, taking the connecting line of the third detecting unit 13 and the fourth detecting unit 14 as the x-axis, the connecting line of the fourth detecting unit 14 and the second detecting unit 12 is taken as the y-axis, the connecting line of the fourth detecting unit 14 and the sixth detecting unit 16 is taken as the z-axis, the coordinates of the geometric centers of the first to sixth detecting units are (-l/2, l/2, 0), (-l/2, -l/2, 0), (-l/2, -l/2, l), (l/2, -l/2, l), the angle between the projection of the target flight trajectory on the first plane xoy and the y-axis is α, and the angle between the projection of the target flight trajectory on the second plane xoz and the z-axis is β.

The projection velocity calculation process is given below by taking the first plane as an example. FIG. 3 is a schematic diagram of the first plane xoy projection velocity calculation implemented according to the above arrangement, see FIG. 3, O₁、O₂、O₃、O₄The geometric centers of the first detection unit to the fourth detection unit, respectively. The projection of the target flight path on the first plane is AB, M₁、M₂、M₃、M₄Are each O₁、O₂、O₃、O₄The closest point of the distance AB, the zero-crossing point time of the acquisition of the first detection unit to the fourth detection unit is t at the same time coordinate₁、t₂、t₃、t₄The projection speed of the target on the first plane xoy is v_xoy。

As is apparent from the geometrical relationship shown in fig. 3:

$\left\{\begin{array}{c}{v}_{xoy}(t_4-t_1)=\sqrt{2}lcos(\frac{\mathrm{\π}}{4}-\mathrm{\α})\\ v_{xoy}(t_3-t_2)=\sqrt{2}lsin(\frac{\mathrm{\π}}{4}-\mathrm{\α})\end{array}\right.$

solving the above equation system can obtain:

in the same way, the projection velocity v of the object on the second plane xoz can be obtained_xoz：

Wherein, t₅、t₆The zero-crossing time acquired by the fifth detection unit 15 and the sixth detection unit 16. Therefore, the detection of the target three-dimensional speed is realized.

Through the process, the invention realizes the accurate detection of the low-speed small target three-dimensional speed through 6 sound sensors, has simple principle, easy realization and low cost, and is suitable for large-area popularization in engineering application. Furthermore, a plurality of groups of sound sensors are arranged in the flight area of the target in a similar mode to form a sensor network, so that the whole-course three-dimensional speed of the target can be accurately detected, and data support is provided for the next step of interception, precaution and supervision.

Fig. 4 shows a stereo velocity detection system of a low-slow small target based on sound intensity detection, which is shown in fig. 4 and comprises a detection module 101 and a velocity calculation module 102. The following are respectively detailed:

the detection module 101 comprises at least 4 acoustic sensors, arranged in two planes perpendicular to each other below the target flight area, and each of the two planes comprises at least 3 acoustic sensors. The sound sensor is used for acquiring the moment when the noise amplitude is maximum as the zero crossing point moment when the target approaches.

As a preferable scheme, the sound sensor takes the time when the noise amplitude of the frequency band of 100-1000 Hz is maximum as the zero crossing point time. Meanwhile, in a preferred embodiment of the present invention, the noise frequency acquired by the acoustic sensor before the zero-crossing point time is greater than the noise frequency acquired by the acoustic sensor after the zero-crossing point time. Therefore, more accurate extraction of the zero crossing point moment is realized.

The speed calculation module 102 is configured to calculate projection speeds of the target on the two planes according to the zero-crossing time acquired by each sound sensor. The specific calculation method is similar to the foregoing formula 3, and is not described in detail here.

In the preferred embodiment of the present invention, the detection module 101 comprises 6 acoustic sensors distributed in a first plane and a second plane perpendicular to each other.

Specifically, the first acoustic sensor, the second acoustic sensor, the third acoustic sensor, and the fourth acoustic sensor are distributed on the first plane to form a first square. The third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are distributed on the second plane to form a second square with the same side length as the first square. The first sound sensor and the fourth sound sensor are located at the diagonal position of the first square, and the second sound sensor and the third sound sensor are located at the diagonal position of the first square. The third sound sensor and the sixth sound sensor are located at the diagonal position of the second square, and the fourth sound sensor and the fifth sound sensor are located at the diagonal position of the second square.

As a preferred solution, the velocity calculating module 102 calculates the projection velocities of the target on the first plane and the second plane by using equations 4 and 5:

wherein v is_xoyIs the projection velocity, v, of the object on the first plane_xozIs the projection velocity, T, of the object in the second plane₁、T₂、T₃、T₄、T₅、T₆The zero-crossing time points obtained by the first sound sensor, the second sound sensor, the third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are respectively, and l is the side length of the first square.

In the specific application, the sound sensors can be arranged on the top of a roof or a street lamp according to the actual environment. Meanwhile, a group of detection modules can be arranged at regular intervals to realize the whole-process monitoring of the target.

According to the method and the system for detecting the three-dimensional speed of the low and slow small targets based on the sound intensity detection, provided by the invention, the projection speeds of various low and slow small targets in the air on two planes are conveniently detected by arranging a plurality of low-cost sound sensors on the top ends of a roof, a street lamp and the like to form a sensor network. When the sensor network is arranged in a large number in a defense area, the whole-process monitoring of the flight speed of low and slow small targets can be well realized.

Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer readable storage medium, such as: ROM/RAM, magnetic disk, optical disk, etc.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims (10)

1. A low-slow small target three-dimensional speed detection method based on sound intensity detection is characterized by comprising the following steps:

s1, at least 4 detection units are arranged below a target flight area, the detection units are distributed on two planes which are perpendicular to each other, and each plane at least comprises 3 detection units;

s2, when the target approaches, each detection unit acquires the time closest to the target as the zero crossing point time;

and S3, calculating the projection speeds of the target on the two planes according to the zero-crossing point moment acquired by each detection unit.

2. The method according to claim 1, wherein the not less than 4 detection units are in particular 6 detection units; and

the 6 detection units are distributed on a first plane and a second plane which are perpendicular to each other; the first plane comprises a first detection unit, a second detection unit, a third detection unit and a fourth detection unit which form a first quadrangle in the 6 detection units, and the second plane comprises a third detection unit, a fourth detection unit, a fifth detection unit and a sixth detection unit which form a second quadrangle in the 6 detection units; wherein,

the first detection unit and the fourth detection unit are located at diagonal positions of the first quadrangle, and the third detection unit and the sixth detection unit are located at diagonal positions of the second quadrangle.

3. The method of claim 2, wherein the first quadrilateral and the second quadrilateral are squares of equal length.

4. The method according to claim 3, wherein step S3 is specifically: calculating the projection speeds of the target on the first plane and the second plane by using a formula 1 and a formula 2 according to the zero crossing point time acquired by each detection unit;

wherein v is_xoyIs the projection velocity, v, of the object on the first plane_xozIs the projection velocity of the object on the second plane, t₁、t₂、t₃、t₄、t₅、t₆Respectively being a first detection unit and a second detection unitAnd the zero-crossing point time acquired by the second detection unit, the third detection unit, the fourth detection unit, the fifth detection unit and the sixth detection unit is the side length of the first quadrangle.

5. The method of any one of claims 1-4, wherein the detection unit is an acoustic sensor.

6. The method of claim 5, wherein the method further comprises: and taking the moment when the noise amplitude acquired by the sound sensor is maximum as the zero crossing point moment.

7. The method of claim 6, wherein the acoustic sensor acquires a noise frequency before the zero-crossing time that is greater than a noise frequency acquired after the zero-crossing time.

8. A low-slow small target stereo velocity detection system based on sound intensity detection is characterized by comprising:

the detection module comprises not less than 4 sound sensors and is arranged on two planes which are perpendicular to each other below a target flight area, and each plane of the two planes at least comprises 3 sound sensors; the sound sensor is used for acquiring the moment when the noise amplitude is maximum as the zero crossing point moment when the target approaches;

and the speed calculation module is used for calculating the projection speeds of the target on the two planes according to the zero-crossing point moment acquired by each sound sensor.

9. The system of claim 8, wherein the detection module comprises 6 acoustic sensors distributed in a first plane and a second plane perpendicular to each other; wherein,

the first sound sensor, the second sound sensor, the third sound sensor and the fourth sound sensor are distributed on the first plane to form a first square;

the third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are distributed on the second plane to form a second square with the same side length as the first square;

the first sound sensor and the fourth sound sensor are located at the diagonal position of the first square, and the third sound sensor and the sixth sound sensor are located at the diagonal position of the second square.

10. The system according to claim 9, wherein the calculating of the projection velocities of the object in the two planes according to the zero-crossing points acquired by each sound sensor is specifically:

calculating the projection speeds of the target on the first plane and the second plane by using a formula 4 and a formula 5 according to the zero crossing point time acquired by each sound sensor;

wherein v is_xoyIs the projection velocity, v, of the object on the first plane_xozIs the projection velocity, T, of the object in the second plane₁、T₂、T₃、T₄、T₅、T₆The zero-crossing time points obtained by the first sound sensor, the second sound sensor, the third sound sensor, the fourth sound sensor, the fifth sound sensor and the sixth sound sensor are respectively, and l is the side length of the first square.