CN102435299A - A Miniature Vibration Sensor Array and Its Application in Ground Target Tracking - Google Patents

Abstract

The invention relates to a micro vibration sensor array and application thereof in ground target tracking, which is characterized in that a PCB is integrally packaged with a plurality of same miniaturized MEMS vibration sensor chips, and corresponding vibration signal processing circuits are also integrated on the same PCB. A plurality of vibration sensor chips are distributed in a cross array mode to form a miniaturized array. When a certain ground target is measured, the sensor is placed in the plane, the distance and the direction of the target can be determined according to the coordinate of each array element of the sensor and the time correlation of each output signal, and the type of the target, such as whether a person or a vehicle is present or not, can be determined according to the frequency spectrum characteristics of each array element output signal, so that the target can be comprehensively detected and positioned. That is, the invention provides a micro vibration sensor array capable of simultaneously detecting the distance, the direction and the type of a ground moving target.

Description

A Miniature Vibration Sensor Array and Its Application in Ground Target Tracking

technical field

The invention relates to a micro-vibration sensor array and its application in ground target tracking. More precisely, the invention relates to a micro-sensor array composed of a plurality of micro-vibration sensors, which can be used to track and locate ground moving targets A vibration sensor that measures and detects the distance, azimuth, and target type of ground moving targets.

Background technique

At present, traditional vibration sensors used for ground target detection generally adopt a single-sensor approach, and the selection of vibration sensors is usually a moving coil type or a velocity sensor with a MEMS structure. When in use, this single vibration sensor is buried underground, and the signal related to the target is obtained by sensing the ground vibration excited by the ground moving target. By analyzing the characteristics of the target signal, the type of the target can be further determined. This single-sensor-based detection system is widely used in earthquake detection, mineral exploration, and security anti-intrusion systems.

With the promotion of the application of vibration sensors, various applications have also put forward new requirements for detection equipment based on vibration sensors. ability.

The positioning of the vibration source can be achieved by using a distributed optical fiber vibration sensor to locate the vibration target. The basic principle is to use the vibration shock to act on the optical fiber to cause a change in its refractive index, which in turn causes a change in the phase of the light wave. By detecting this change, the point where the optical fiber is acted on is located, so as to detect the position of the vibrating target. However, this method requires that the optical fiber must be laid at the location where the vibration target exists. It is a contact sensor, and the layout method is complicated, maintenance is difficult, and it does not have mobility. It is only suitable for edge detection in fixed areas.

Since only a single sensor structure is used, it cannot meet the needs of detecting the distance and azimuth of the ground target. As a solution, another solution to the positioning of the vibration source is to arrange multiple separate vibration sensor units to form an array. , and then connected to a signal processing device through multiple cables to achieve multi-channel signal acquisition to obtain the distance and direction information of the target, such as a multi-vibration array for prospecting; or use a wireless network to combine multiple separate single-vibration The sensors are combined to realize the detection of the distance and orientation of the target, such as a wireless sensor network. Whether it is wired or wireless, the array structure of this discrete combination is usually more complicated, the hardware cost is high, the volume is large, and the area is wide. In addition, the consistency between the sensors is also difficult to guarantee, resulting in obvious differences between signals. Higher requirements are also put forward for signal processing methods and hardware requirements.

Therefore, in response to this demand, combined with the latest development of shock sensors, the present invention intends to propose a miniature shock sensor array for ground target tracking.

Contents of the invention

In order to overcome the shortcomings of the existing single-type shock sensor equipment that can only detect the type of ground target and cannot simultaneously realize the positioning of the target, the purpose of the present invention is to provide a miniature shock sensor array and its application in ground target tracking. The provided miniature sensor array can simultaneously detect information such as the type, distance and azimuth of ground moving targets.

The technical solution adopted by the present invention to solve the technical problem is: adopt the mode of integrated packaging, a plurality of MEMS vibration sensors are installed on the PCB circuit board according to the mode of one in the center, and the other four sides are equidistantly arranged, and the remaining space of the PCB circuit board For the corresponding processing circuit. The processing circuit part includes a multi-channel analog signal amplification and filtering module, an AD conversion module and an algorithm processing module (MCU).

As shown in FIG. 1 , the MEMS shock sensor of the present invention is mounted on a PCB in an integrated package.

The MEMS vibration sensor is fixed on the PCB board with an adhesive. After the adhesive is cured, it can ensure good contact between the sensor and the PCB board. The output signal can be directly collected, amplified and analyzed by the signal processing circuit to realize the positioning, identification and classification of the vibration source.

The micro shock sensor array adopts shock sensors made based on MEMS (Micro Electro Mechanical System) technology to form a vibration array, which can be produced in batches like making integrated circuits, and has good performance consistency. Because the shock sensor device made by MEMS technology The volume is usually only a few millimeters in size. It is made of silicon materials. It uses structures such as variable capacitance structures or piezoresistors to sense vibration signals. The working voltage can be as low as 3-5V. It has good interface compatibility with integrated circuits, so it can It is convenient to integrate and manufacture chip-on-chip systems. At present, there is an integrated hybrid packaging process to realize the technology of integrating MEMS sensors and related processing circuits on the same circuit board.

Using the integrated hybrid packaging process, several MEMS vibration sensors can be easily integrated on the PCB circuit to form a miniaturized cross vibration sensor array, so as to realize the positioning, identification and classification functions of ground moving targets.

The basic principle of the positioning of the cross vibration sensor array is to determine the distance of the vibration source by using the time difference between the signal of the vibration source and the different sensors in the sensor array. Due to the small size of the cross array, the time difference is also very small. In order to ensure sufficient positioning accuracy, the sampling rate of the signal must be increased accordingly, and the current circuit technology can meet the requirements.

The recognition and classification function of the vibration sensor to the ground moving target is realized by analyzing the frequency spectrum characteristics of the vibration signal source, and different vibration targets can be identified by comparing the frequency distribution characteristics. The technology in this aspect is currently mature and can be applied to the present invention .

The basic modules of the signal processing circuit are shown in Fig. 2, for the convenience of description, five sensors are taken as an example for illustration.

As shown in Figure 2, the five sensors forming the cross array convert the sensed vibration signal into a weak electrical signal output. The vibration sensor used is a MEMS vibration sensor chip developed by Shanghai Microsystems, Chinese Academy of Sciences. The frequency response range can be selected >0- 1KHz, the sensitivity is about 300mv/cm/S.

The signal amplification and filtering module amplifies the output signal of the vibration sensor and filters out the noise. Its parameters are generally a gain of 60-80db and a bandwidth of not less than 10KHz.

The amplified signal is sampled by multiple high-speed AD chips and converted into a digital signal. The number of channels of the AD chip is not less than 5, the sampling rate is not lower than 10m/S, and the resolution is not lower than 12bit.

The converted digital signal is received and processed by the MCU unit. The MCU unit is usually a high-speed single-chip microcomputer or DSP chip, with a built-in time difference positioning algorithm module and a spectrum analysis and classification identification module. The time difference positioning algorithm module is used to calculate the time difference between multiple sensor signals to realize the positioning function of the vibration source, and the spectrum analysis and classification recognition module realizes the classification and recognition of the vibration target through the spectrum analysis and comparison of the vibration signals.

It can be seen that the present invention adopts the form of integrated packaging to manufacture a plurality of miniaturized shock sensors and corresponding processing circuits on the same PCB board, and the distance between the shock sensors is only on the order of a few centimeters. The purpose of miniaturization, and give full play to the advantages of the array sensor, to achieve the function of detecting the target type and target positioning at the same time.

The present invention provides a miniature shock sensor array for ground target tracking, comprising at least one PCB circuit board, and a miniature shock sensor placed in the center of the PCB circuit board, placed at equal intervals around the miniature shock sensor placed in the central position For other miniature vibration sensors of the same type, the miniature vibration sensor is installed on the PCB circuit board in the form of an integrated package. The vibration signal processing circuit includes a multi-channel analog signal amplification and filtering module, AD conversion module and algorithm processing module are also included on the PCB circuit board.

Among them, ① the arrangement mode of the shock sensors forming the array is the cross array element mode or other centrosymmetric mode;

② The number of shock sensors forming the array can be 3, 5, 5 or more;

③ The shock sensors that make up the array are miniaturized, and can be velocity or acceleration sensor chips made with MEMS technology, or velocity or acceleration sensor chips made with other process conditions;

④The distance between the shock sensor placed in the center of the array and the surrounding shock sensors is on the order of centimeters, generally about 5-6cm.

In a word, the miniature vibration sensor array provided by the present invention is integrated and packaged with multiple miniaturized identical MEMS vibration sensors on one PCB circuit board, and the corresponding vibration signal processing circuit is also integrated on the same PCB board. Multiple shock sensors are arranged in a cross array to form a miniaturized array. When measuring a ground target, you only need to place the sensor in the plane, and the distance and direction of the target can be determined according to the coordinates of each array element of the sensor itself and the time correlation of their respective output signals. The characteristics can determine the type of the target, such as whether it is a person or a vehicle, so as to realize the comprehensive detection and positioning of the target. That is to say, it is a miniature shock sensor array that can simultaneously detect the distance, azimuth and type of ground moving targets.

Description of drawings

Fig. 1 is a schematic diagram of the MEMS vibration sensor provided by the present invention installed on a PCB.

Fig. 2 The signal processing circuit module of the MEMS shock sensor array provided by the present invention.

Figure 3 is a diagram of an embodiment of the present invention.

In Fig. 3, 1 is a PCB circuit board, 2 is a shock sensor arranged at the center of the PCB board, 3, 4, 5, 6 are shock sensors arranged at equal intervals around, and 7 is a processing circuit module.

Fig. 4 is a schematic circuit diagram of the present invention.

In Fig. 4, 2, 3, 4, 5, 6 are shock sensors arranged on the PCB board, 8 is a multi-channel analog signal amplification and filtering module, 9 is a multi-channel AD conversion circuit module, and 10 is an algorithm processing module (MCU ).

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

See Figure 3 for details. For convenience, this embodiment still uses a 5-element shock sensor array as an example for detailed description. In practice, a shock sensor array that can integrate more elements can be fabricated according to needs, and its basic structure is similar.

In the figure, 1 is the PCB circuit board, and 2 is the vibration sensor installed in the center of the PCB circuit board. The vibration sensor is a miniaturized vibration sensor chip made by MEMS technology. The area size is generally about 4×6mm, and the vibration induction direction is perpendicular to On the surface of the PCB circuit board, the remaining 4 vibration sensors are other miniaturized vibration sensor chips arranged at equal intervals around the PCB board. The distance between the sensor chip and (2) is the same, the distance is about 5cm, and the installation method and vibration sensing direction are the same as (2). The vibration sensor chip forms a cross array and is tightly mounted on the surface of the PCB board to reduce the attenuation of the vibration signal from the PCB board to the vibration chip. In addition to installing the vibration sensor chip on the PCB, the rest is the corresponding processing circuit. Its basic composition is shown in Figure 2, including multi-channel analog signal amplification and filtering modules, multi-channel AD conversion modules, and algorithm processing modules.

When the miniature vibration sensor array of the present invention measures a certain ground target, only the sensor needs to be placed in the plane, and the distance and direction of the target can be determined according to the coordinates of each array element of the sensor itself and the time correlation of the respective output signals. The spectrum characteristics of the output signals of each array element can determine the type of the target, such as whether it is a person or a vehicle, so as to realize the comprehensive detection and positioning of the target. How to implement the algorithm for locating and classifying objects does not belong to the scope of the present invention, and will not be described here.

Claims (10)

1. A micro vibration sensor array is characterized in that a plurality of miniaturized vibration sensors and corresponding signal processing circuits are manufactured on the same PCB in an integrated packaging mode; wherein,

firstly, the plurality of miniaturized vibration sensors adopt an integrated packaging mode, a plurality of MEMS vibration sensors of the same type form a cross array element vibration sensor array according to a mode that one sensor is arranged in the center and the rest sensors are arranged at equal intervals around the sensor, and the cross array element vibration sensor array is arranged on a PCB (printed circuit board);

the signal processing circuit comprises a multi-channel analog signal amplifying and filtering module (8), an AD conversion module (9) and an algorithm processing module (10);

the vibration sensor forming the cross array element converts the sensed vibration signals into weak electric signals to be output, the weak electric signals are amplified and filtered to remove noise through a multi-channel analog signal amplification and filtering module (8), the amplified signals are sampled and converted into digital signals through an AD conversion module (9), and the converted digital signals are received and processed by an MCU unit.

2. The array of claim 1, wherein:

firstly, arranging the vibration sensor arrays forming the array in other centrosymmetric modes;

and the number of the vibration sensors forming the array is 3, 5 or more than 5.

3. The array of claim 1 wherein said MEMS shock sensors are secured to the PCB by adhesive and gold wire leads are used to connect the signal pins of the sensors to the circuit chips on the PCB.

4. The array of claim 1 wherein the distance between the centrally located shock sensor and the equally spaced shock sensors disposed thereabout is on the order of centimeters.

5. The array according to any of claims 1-4, wherein said miniaturized seismic sensor has a frequency response in the range of > 0 to 1kHz and a sensitivity of 300 mv/cm/s.

6. The array of claim 1, wherein the signal processing circuit includes

a) The gain of the signal amplifying and filtering module is 60-80db, and the bandwidth is not less than 10 kHz;

b) the number of channels in the AD conversion module is not less than 5, the sampling rate is not less than 10m/s, and the resolution is not less than 12 bits;

c) the algorithm processing module is a high-speed single chip microcomputer or a DSP chip, and a time difference positioning module and a channel analysis and classification identification module are arranged in the algorithm processing module.

7. An array as claimed in claim 1, 2, 3 or 4, wherein the vibration sensor has an area of 4 x 6mm and the vibration sensing direction is perpendicular to the surface of the PCB board.

8. The array of claim 1 wherein the miniaturized seismic sensor chips comprising the array are velocity or acceleration type sensors fabricated using MEMS technology or velocity or acceleration type sensors fabricated using other process conditions.

9. The array of claim 4 wherein the distance between the centrally located shock sensor and the equally spaced shock sensors disposed thereabout is 5-6 cm.

10. Use of an array according to any of claims 1 to 4 or 6 to simultaneously detect the range, azimuth and type of a ground moving object; when a certain ground target is measured, the sensor is placed in the plane, the distance and the direction of the target can be determined according to the coordinates of each array element of the sensor and the time correlation of each output signal, and the target can be determined to be a person or a vehicle according to the frequency spectrum characteristics of each array element output signal; therefore, the comprehensive detection and positioning of the target are realized.

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