RU2352995C1 - Radio-wave detection method of moving objects - Google Patents

Abstract

FIELD: radio-engineering.

SUBSTANCE: invention refers to procedure dealing with detection of moving objects, and can be used in security systems of various purpose. The effect of the proposed invention is simplifying radio-wave detection of moving objects, and enlarging functional capabilities. The proposed radio-wave detection method of moving objects, which is based on radio-frequency microwave-range identification technology, consists in irradiating the space of controlled zone with continuous variable radio signal, in storing the energy with passive radio-frequency mark, in receiving therefrom the signal response, and in its processing; at that presence of penetrator is determined by change of time delay of signal response entered the recording device as a consequence of radio-frequency signal amplitude change.

EFFECT: analysis of signal response time delay allows obtaining more accurate information on presence of penetrator in controlled zone than analysis of electromagnetic field characteristics does.

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Description

The invention relates to the field of technology related to the detection of moving objects, and can be used in security systems for various purposes.

Most existing systems for continuous monitoring of the safety of an object use wired communication lines and require mandatory power supply to all elements of the system.

Known radio wave intruder detection means [1], including a pulse generator, a transmission line, a receiver with detection channels.

A known method and device for radio wave detection of an intruder [2], where as a sensitive element of the security detector use a wired telecommunication line in the open waveguide mode of surface radio waves with a transmitter and receiver of RF electromagnetic waves, compare the amplitude level of the RF electromagnetic waves at the receiving point with reference level and form an alarm.

The disadvantage of such structures is the need to provide a bulky wired communication line and the inability to determine the location of the intruder. In addition, this method is subject to a strong influence of weather conditions.

Closest to the proposed technical solution is a radio wave method for detecting moving objects, based on the registration of changes in the electromagnetic field when an object crosses a volume detection zone [3]. The method consists in the fact that they analyze the characteristics of the electromagnetic field in the control zone of the emitter, namely the standing wave coefficient. According to the dynamics of changes in the amplitude of the standing wave coefficient, a decision is made on the presence of an intruder at a guarded line. Thus, the propagation of the radio wave and its reflection from the obstacle in the event of its occurrence are used as a sensitive element in the radio wave method for detecting moving objects.

The disadvantage of the described method is the inability to determine the exact location of the intruder, as well as the direction of its movement.

The objective of the invention is to simplify the radio wave means of detecting moving objects and to expand the functionality, namely determining the location (coordinates) of the detected object and the direction of its movement in space.

The task is achieved through the use of radio frequency identification technology. RFID technology is implemented by means of an RF system, which incorporates 2 main elements: an RF tag and a reader.

The proposed radio wave method for detecting moving objects, based on the microwave frequency identification technology of the microwave range, consists in irradiating the space of the controlled zone with a continuous variable radio signal, accumulating energy with a passive radio frequency tag, receiving a response signal from it and processing it. This method of detecting moving objects is characterized in that the presence of an intruder is determined by changing the time delay of the response signal to the recording device due to a change in the amplitude of the radio frequency signal. Analysis of the time delay of the response signal allows you to get more accurate information about the location of the intruder in the controlled area than the analysis of the characteristics of the electromagnetic field.

The proposed system of radio wave detection of moving objects includes 2 lines of protection. On the first of them, which is a controlled object, readers are located, on the second - radio-frequency tags. The interaction between the reader and the RF tag is carried out wirelessly, which is the main advantage of the proposed system.

The reader is an electromagnetic wave transceiver equipped with an antenna that emits electromagnetic energy into the surrounding space. A passive RF tag receives a signal from the reader and generates a response signal, which is received by the reader’s antenna, processed by its electronic unit and sent to the computer via the interface. The passive RF tag does not require an independent power source, has small dimensions and weight, has an unlimited service life. Each RFID tag has its own unique serial number (code) and may contain other data that is stored in memory.

The system of radio wave detection of moving objects is illustrated by the following drawing, which shows a structural diagram of the device system that implements a radio wave method for detecting moving objects.

The radio wave detection system of moving objects comprises a reader (1) with an antenna (2) and passive RF tags (3).

The system operates as follows.

The microcontroller of the reader generates a signal of a certain frequency and power, which is radiated into the surrounding space. The signal arrives at the RF tag, which accumulates electromagnetic energy until the level of the supply voltage is sufficient to reflect the response signal with the tag. The response modulated signal arrives at the reader with a certain time delay equal to the time it takes for the signal to propagate and the energy to be stored by the tag. When the situation changes - the appearance in the protected zone of the intruder - the absorption of electromagnetic energy by the body of the intruder will occur. If the power level of the response signal falls below the minimum power level distinguishable by the reader, the response signal will either not be detected by the reader or will arrive with a longer time delay, which will signal the appearance of an intruder in the controlled area. In addition to the fact of detection of the intruder, the system allows you to determine the coordinates of the object that invaded the protected area, due to the fact that the information on the reader comes from several radio frequency tags. That mark, the response from which came with a longer time delay, is closest to the intruder. Thus, knowing the coordinates of this label, you can accurately determine the coordinates of the invading object. Information about the delays in the response signals of each label, received or not accepted by the reader at any given time at the interface, is sent to the computer. Based on the changes in the time delay, it is concluded that there is an intruder in the controlled area, its coordinates and direction of movement.

In addition, the proposed system carries out self-monitoring of its integrity. If one of the RF tags fails or is stolen, then the signal from it will not go to the reader's receiver, and this will be a signal of a violation of the integrity of the system.

The system does not require direct visibility between the reader and the tag, since the radio signal easily penetrates non-metallic materials (wood, paper, paint, dirt, etc.).

Thus, the implementation of the proposed technical solution allows you to:

- carry out monitoring of objects whose control it is desirable to hide (due to wireless communications and the small size of the RF tag);

- receive more accurate information about the location of the intruder in the controlled area (by analyzing the time delay of the response signal);

- receive complete information about the coordinates of the location of the intruder and the direction of his movement (due to a comprehensive analysis of all the information coming from several readers);

- reduce the influence of weather conditions (due to the use of radio frequency technology and the fact that readers can be placed inside the object of protection);

- reduce the cost and increase the life of the detection system to the maximum possible (due to the use of passive RF tags and wireless communication).

Information sources

1. RU, 2258258, G08B 13/24, publ. 08/10/2005.

2. RU, 2145441, G08B 13/08, publ. 12/10/2000.

3. RU, 2292600, G08B 13/24, publ. 01/27/2007.

Claims (1)

A method of radio wave detection of moving objects, including irradiating the space of the controlled zone with a radio signal, recording and processing a response signal, characterized in that the radiation of the space of the controlled zone is carried out by a continuous alternating radio signal of a certain frequency and power using reading devices located on the first boundary of the guard and at a distance from each other , each of which is a transceiver of electromagnetic waves with an antenna, accumulate radiated energy By using the passive RFID tags located on the second line of guard of the monitored zone until the supply voltage level is sufficient for the passive RFID tags to reflect the response signals, they receive modulated response codes of the passive RFID tags on the readers with a certain time delay equal to the signal propagation time and on the accumulation of energy by passive radio-frequency tags, while the presence of the intruder is determined by the change in time delays in the receipt of response signals from RF tags to the readers, register and process the response signals from passive RF tags by analyzing their time delays and obtain the coordinates of the location of the intruder and the direction of his movement along the known coordinates of the passive RF tag that is closest to the intruder and the response from which to the readers came with a longer time delay, while the interaction between the readers and the radio Tag-frequency provided by wireless communication.