CN204331053U - A kind of bottled dangerous liquid detection system based on radar sensor - Google Patents

Abstract

The utility model relates to a detection system for bottled dangerous liquid based on a radar sensor, which comprises a microwave radar sensor, an AD converter, a data processor, a display and an alarm device. The microwave radar sensor, its output end is connected with the input end of AD converter. The AD converter is interactively connected with the data processor. The output end of the data processor is connected with the input end of the display and alarm device. It can be seen from the above technical solutions that the utility model can make up for the deficiencies of the prior art, and has the characteristics of high integration, low power consumption, and fast detection speed.

Description

A detection system for bottled dangerous liquid based on radar sensor

technical field

The utility model relates to the technical field of explosion-proof safety inspection, in particular to a detection system for bottled dangerous liquid based on a radar sensor.

Background technique

In recent years, serious incidents caused by the use of dangerous liquids have occurred frequently. Criminals carry containers containing dangerous liquids into densely populated public places to carry out terrorist attacks, which not only cause a large number of casualties and property losses, but also cause adverse effects on social harmony and stability. Influence. How to prevent dangerous liquids such as gasoline, alcohol, and banana water from entering public places is an urgent problem in the current security inspection field.

At present, most of the dangerous liquid detection devices on the market use X-ray projection, Raman spectroscopy, quasi-electrostatic tomography and ultra-broadband pulsed microwave technology, but they all have limitations to varying degrees, such as huge X-ray equipment, minimum detection The amount is large, and the rate of false positives is high; Raman spectroscopy technology takes a long time to detect, and the container is limited to transparent glass or plastic bottles; quasi-electrostatic tomography technology is susceptible to electromagnetic interference in the surrounding environment, and its accuracy is poor; ultra-wideband pulse microwave technology circuit implementation The method is complicated, and the low degree of integration is not conducive to the miniaturization of equipment.

Utility model content

The purpose of this utility model is to provide a detection system for bottled dangerous liquids based on radar sensors, which can make up for the deficiencies of the prior art, and has the characteristics of high integration, low power consumption, and fast detection speed.

In order to achieve the above object, the utility model adopts the following technical solutions:

A radar sensor-based detection system for bottled dangerous liquids includes a microwave radar sensor, an AD converter, a data processor, and a display and alarm device.

Described microwave radar sensor, its output end is connected with the input end of AD converter; Described AD converter is interactively connected with data processor; Described data processor, its output end is connected with the input end of display and alarm device connected.

The microwave radar sensor includes a signal transmitting channel and a signal receiving channel. The signal transmitting channel includes a voltage controlled oscillator, a first Wilkinson power divider, a transmitting microstrip antenna array, a second Wilkinson power divider and a 90° phase shifter. The signal receiving channel includes a receiving microstrip antenna array, a low noise amplifier, a third Wilkinson power divider, a first mixer, a second mixer, a first low-pass filter and a second low-pass filter device.

The output terminal of the voltage-controlled oscillator is connected to the input terminal of the first Wilkinson power divider. The output end of the first Wilkinson power splitter is respectively connected to the transmitting microstrip antenna array and the input end of the second Wilkinson power splitter. The second Wilkinson power divider, its output end is connected with the input end of the first mixer and the second mixer respectively, and the second Wilkinson power divider is connected with the second mixer through a 90° phase shifter connected. The input end of the receiving microstrip antenna array is connected with the output end of the transmitting microstrip antenna array, and the output end is connected with the input end of the low noise amplifier. A low noise amplifier, the output terminal of which is connected with the input terminal of the third Wilkinson power divider. The output terminals of the third Wilkinson power divider are respectively connected to the input terminals of the first mixer and the second mixer. The output terminal of the first mixer is connected to the input terminal of the AD converter through the first low-pass filter. The output terminal of the second mixer is connected to the input terminal of the AD converter through the second low-pass filter.

Further, the AD converter adopts ADS1256 analog-to-digital converter.

Further, the data processor adopts STM32 chip.

Further, the oscillation frequency of the voltage-controlled oscillator is 24GHz.

It can be seen from the above technical solutions that the utility model has the characteristics of simple implementation, high integration, low power consumption, and fast detection speed. First of all, by adopting a voltage-controlled oscillator with an oscillation frequency of 24GHz, not only can the detection system work in the 24GHz frequency range, but also the size and volume of the antenna array can be reduced, and the integration of the detection system can be improved. 24GHz is a radar operating frequency band that is universally used in the world as stipulated by ISM. It complies with the power limit stipulated by the FCC (Federal Communications Commission, US Federal Communications Commission), has the advantages of no interference to the outside world, and is green and environmentally friendly. Secondly, since the sample to be inspected needs to cover the antenna, the smaller the antenna, the smaller the amount of sample to be inspected, thereby improving the detection sensitivity. Thirdly, since the system is a point-frequency continuous wave, the processed signal is a DC signal, which does not require frequency sweep and conversion, so the single detection time is greatly reduced, and the system is also optimized. In the utility model, the microwave radar sensor transmits microwave signals to the liquid to be tested through the transmission channel, and the receiving channel receives the signal returned by the liquid to be tested, and the two-way orthogonal signals I and Q after frequency mixing and filtering are transmitted to the AD converter , the signal after AD conversion is sent to the data processor, and the data processor controls the working status of the display and alarm device according to the power of the echo signal.

Description of drawings

Fig. 1 is a functional block diagram of the utility model.

in:

1. Receiving microstrip antenna array, 2. Low noise amplifier, 3. The third Wilkinson power divider, 4. The second mixer, 5. The second low-pass filter, 6. AD converter, 7. Data processor, 8. Display and alarm device, 9. First mixer, 10. First low-pass filter, 11. 90° phase shifter, 12. Second Wilkinson power divider, 13. Emitter Microstrip antenna array, 14. First Wilkinson power divider, 15. Voltage controlled oscillator.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described:

As shown in FIG. 1 , a radar sensor-based bottled dangerous liquid detection system includes a microwave radar sensor, an AD converter 6 , a data processor 7 and a display and alarm device 8 . Radar sensors are generally used in speed measurement, distance measurement, and azimuth measurement. The utility model uses the radar sensor for liquid detection for the first time.

Described microwave radar sensor, its output end is connected with the input end of AD converter 6; Described AD converter 6 is interactively connected with data processor 7; Described data processor 7, its output end is connected with display and alarm The input of device 8 is connected. Preferably, the AD converter adopts ADS1256 analog-to-digital converter. Described data processor adopts STM32 chip.

The microwave radar sensor includes a signal transmitting channel and a signal receiving channel. The signal transmission channel includes a voltage controlled oscillator 15 , a first Wilkinson power divider 14 , a transmitting microstrip antenna array 13 , a second Wilkinson power divider 12 and a 90° phase shifter 11 . The oscillation frequency of the voltage-controlled oscillator is 24GHz. The signal receiving channel includes a receiving microstrip antenna array 1, a low noise amplifier 2, a third Wilkinson power divider 3, a first mixer 9, a second mixer 4, and a first low-pass filter 5 and a second low-pass filter 10.

The output terminal of the voltage-controlled oscillator 15 is connected to the input terminal of the first Wilkinson power divider 14 . The output terminals of the first Wilkinson power divider 14 are respectively connected to the transmitting microstrip antenna array 13 and the input terminals of the second Wilkinson power divider 12 . The second Wilkinson power divider 12, its output end is connected with the input end of the first mixer 9, the second mixer 4 respectively, the second Wilkinson power divider 12 is connected with the 90 ° phase shifter 11 and The second mixer 4 is connected. The input end of the receiving microstrip antenna array 1 is connected to the output end of the transmitting microstrip antenna array 13 , and the output end is connected to the input end of the low noise amplifier 2 . The output terminal of the low noise amplifier 2 is connected with the input terminal of the third Wilkinson power divider 3 . The output terminals of the third Wilkinson power divider 3 are respectively connected to the input terminals of the first mixer 9 and the second mixer 4 . The output terminal of the first mixer 9 is connected to the input terminal of the AD converter 6 through the first low-pass filter 10 . The output terminal of the second mixer 4 is connected to the input terminal of the AD converter 6 through the second low-pass filter 5 .

The working principle of the utility model is:

The voltage-controlled oscillator 15 oscillates and transmits 24GHz microwave signals, which are divided into two signals by the first Wilkinson power divider 14: one is transmitted through the transmitting microstrip antenna array 13, and the other is transmitted through the second Wilkinson power divider The device 12 is divided into two signals. One of the two signals output by the second Wilkinson power divider 12 enters the first mixer 9 , and the other enters the second mixer 4 after being phase-shifted by the 90° phase shifter 11 . At this time, the two signals split by the voltage-controlled oscillator 15 are used as local oscillator signals of the two mixers.

The echo signal received by the receiving microstrip antenna array 1 is first amplified by the low-noise amplifier 2, and then divided into two signals by the third Wilkinson power divider 3, and then passed through the first mixer 9 and the second mixer respectively. Frequency mixer 4 performs frequency mixing with the local oscillator signals of the two mixers.

The DC signal obtained after the mixing by the first mixer 9 and the second mixer 4 is processed by the first low-pass filter 10 and the second low-pass filter 5 respectively, and then processed by the AD converter 6 (ADS1256) converts two analog voltage signals into digital signals, and outputs them to the data processor 7 (STM32 single-chip microcomputer), and the data processor 7 identifies dangerous liquids and water according to the echo power, and outputs control signals to control the display and alarm devices 8. Depending on the shape of the sample structure, multiple microwave radar sensors can be placed at different positions.

In the utility model, since the frequency of the echo signal is the same frequency as that of the local oscillator signal, it becomes a DC signal after frequency mixing. If it is a single-way mixing frequency, the amplitude and phase relationship of the signal are inseparable, that is, the signal after frequency mixing is k is information related to the amplitude of the mixer and the local oscillator signal, A _RF is the amplitude of the radio frequency signal, is the phase difference between the local oscillator signal and the radio frequency signal, and two channels of frequency mixing can obtain two channels of quadrature signals, that is, I and Q, where:

From this, the amplitude information of the RF signal can be obtained Its magnitude is independent of phase.

The above-mentioned embodiments are only described to the preferred implementation of the utility model, and are not limited to the scope of the utility model. Various modifications and improvements made should fall within the scope of protection determined by the claims of the utility model.

Claims (4)

1. A detection system for bottled dangerous liquids based on a radar sensor, characterized in that it includes a microwave radar sensor, an AD converter (6), a data processor (7) and a display and alarm device (8); The microwave radar sensor, its output terminal is connected to the input terminal of the AD converter (6); the AD converter (6) is interactively connected with the data processor (7); the data processor (7) , the output end of which is connected to the input end of the display and alarm device (8); The microwave radar sensor includes a signal transmitting channel and a signal receiving channel; the signal transmitting channel includes a voltage-controlled oscillator (15), a first Wilkinson power divider (14), a transmitting microstrip antenna array (13) , the second Wilkinson power divider (12) and 90 ° phase shifter (11); the signal receiving channel includes a receiving microstrip antenna array (1), a low noise amplifier (2), a third Wilkinson Power splitter (3), first mixer (9), second mixer (4), first low-pass filter (10) and second low-pass filter (5); The voltage-controlled oscillator (15), its output terminal is connected with the input terminal of the first Wilkinson power divider (14); The antenna array (13) and the input end of the second Wilkinson power splitter (12) are connected; the output ends of the second Wilkinson power splitter (12) are respectively connected to the first mixer (9), the second The input terminals of the two mixers (4) are connected, and the second Wilkinson power divider (12) is connected with the second mixer (4) through a 90° phase shifter (11); the receiving microstrip antenna array (1 ), its input is connected to the output of the transmitting microstrip antenna array (13), its output is connected to the input of the low-noise amplifier (2); the output of the low-noise amplifier (2) is connected to the third Wilkinson The input terminals of the power divider (3) are connected; the output terminals of the third Wilkinson power divider (3) are respectively connected with the input terminals of the first mixer (9) and the second mixer (4); The first mixer (9), its output end is connected to the input end of the AD converter (6) through the first low-pass filter (10); the second mixer (4), its output end is passed through the second low-pass The filter (5) is connected to the input end of the AD converter (6). 2. A radar sensor-based detection system for bottled dangerous liquids according to claim 1, characterized in that: said AD converter (6) adopts ADS1256 analog-to-digital converter. 3. A radar sensor-based bottled dangerous liquid detection system according to claim 1, characterized in that: said data processor (7) adopts STM32 chip. 4. The radar sensor-based detection system for bottled dangerous liquids according to claim 1, characterized in that: the oscillation frequency of the voltage-controlled oscillator (15) is 24 GHz.