CZ35646U1 - Location security system with at least three static sensor units - Google Patents

Description

Location security system with at least three static sensor units

Field of technology

The technical solution concerns the area of security and location systems.

State of the art

Currently, the number of applications of localization systems for people or people in the indoor environment using radio operating in the ultra-wideband frequency band (UWB) is growing significantly. The advantage of these systems is the reliability and high accuracy of determining the position of a special device (locator). The locator is attached to the monitored object, or carried by a person whose position is monitored in real time.

There are also location systems that use other wireless radio technologies, such as Wi-Fi or Bluetooth. These systems mostly work on the principle of measuring the power level of the signal. In addition to systems using radio technology, localization systems using ultrasound or light in the infrared spectrum are also available. The problem with most of these location systems is the limited accuracy of the position measurement.

Real-time location systems (RTLS) can be used to monitor the movement of people within the monitored areas. Checks of the right of entry of persons into the reserved areas can be solved at the application level in the software running on the server, where the program detects the location of a particular locator and tests its presence in user-defined areas.

However, the disadvantage of this solution is zero security against unauthorized persons entering the reserved areas if the person does not carry a locator.

This problem can be solved by an independent security system. There are many security systems today and they are widespread. They often work on the principle of motion detection in a secure area using sensors and a central unit that evaluates signals from sensors and controls actions if predefined conditions are met (sound alarm, sending a message).

Frequently used sensors for detecting the movement of people are passive infrared sensors (PIR - passive infrared) suitably located in the guarded area, which measures the radiation in the infrared light spectrum (thermal energy produced by a person and thermal background radiation).

To reduce false alarms, caused for example by small animals or the flow of warm air from the heating of the building, a PIR sensor is often combined with sensors working on a different principle, where the condition of detecting the movement of a person from both or more sensors must be met. Such sensors can be, for example, Lidar, UWB radar or an acoustic sensor.

Allowing an authorized person to enter the protected area is usually solved using a password, where the person must enter a code into the terminal of the security system (decoding of the guarded area) to prevent the alarm from sounding.

It is also possible to use radio frequency identification (RFID) technology, where an authorized person is entrusted with an RFID device that this person uses at the terminal contains an RFID reader instead of manually entering the password into the terminal using the keyboard.

This RFID device can be active or passive. The passive RFID tag does not contain its own power supply and uses the RFID reader transmission energy for operation.

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With this system, it is possible to secure protected areas against the entry of unauthorized persons who are not entrusted with an RFID tag.

The disadvantage of this security system is the absence of accurate information about the position of the person with the tag inside the protected area. This disadvantage complicates the security of more complex premises, where, for example, it is assumed that the space is divided into zones with different levels of security and at the same time the movement of more authorized persons (with different authorizations) at the same time.

The aim of this application is to present a system which can secure premises against unauthorized movement of persons, both cooperating, carrying entrusted equipment and non-cooperating, ie not equipped with a tag, locator or other equipment, and which also provides real-time information on accurate position of locators.

The essence of the technical solution

The essence of this technical solution is a localization security system, which consists of static sensor units, locators and a server. Static sensor units contain UWB radio, PIR sensor and control chip. The locator contains a UWB radio, a control chip and a power supply. UWB radio is able to generate communication timestamp with a resolution of at least 15 ps.

The static sensor units are located in a protected area with regard to sufficient coverage of the area by the UWB signal, so that it is possible to determine the position of the locator. In a preferred embodiment, each point of the protected space has direct visibility to at least three sensor units.

The "Time Difference of Arrival" (TDOA), "Two Way Ranging" (TWR) or Asynchronous TDOA (A-TDOA) methods can be used to determine the position of the locator.

If the TDOA method is used, the sensor units must be time-synchronized. Time synchronization can be provided both wirelessly and by cable signal. The UWB radios of the sensor units receive short messages sent by the locator and send communication timestamps to the server, where the position of the message source (locator) can be calculated on the basis of their different values.

If the TWR method is used, two-way communication between the sensor unit and the locator takes place via the UWB radio. Part of the communication is the sharing of time stamps of receiving and sending messages of the locator and the sensor unit, on the basis of which the signal propagation time and thus the distance of the locator from the sensor unit can be calculated. The distances of the locator from the sensor units are sent to the server, where the position of the locator is calculated.

The A-TDOA method is an extension of the TDOA method, in which there is no need to synchronize the sensor units in time.

The communication messages between the locator and the sensor unit also include a unique locator identifier.

At the same time, the static sensor units are arranged so that the protected area is sufficiently covered by PIR sensors. PIR sensor signals are sent to the server.

The server provides real-time information on the presence of people in the sensitivity of PIR sensors and information on the location of all activated locators. Based on this information, it is possible to evaluate the security conditions of the guarded areas and trigger appropriate actions, such as an acoustic alarm or sending a message containing a description of the event, or audio or video recording.

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Clarification of drawings

The technical solution will be explained in more detail with the help of the drawings, where Fig. 1, 2, 3 and 4 schematically show the static sensor units used in this solution.

Giant. 1 shows a static sensor unit with a passive infrared PIR sensor

Giant. 2 shows a static sensor unit with a wireless communication interface

Giant. 3 shows a static sensor unit with a cable communication interface

Giant. 4 shows a static sensor unit with a human presence sensor

Examples of technical solutions

Example 1

An exemplary embodiment of a location security system according to claim 5 consists of a server 6, three or more static sensor units 1 and locators 3.

The static sensor units are arranged in the guarded area so that the PIR sensors 4 cover the areas of the guarded area in which the presence of unauthorized persons must be detected and at the same time that the guarded area is sufficiently covered by the UWB signal. Static sensor units measure the distance from locators using the TWR method using UWB radio 2. UWB radio sensor units are also used to send measured distances from locators and PIR sensor signals to server 6. From the received distance data, the server phenomenon calculates the exact position of locators and thus authorized persons. entrusted to the locators. Knowing the exact location of authorized persons and PIR signals of sensors detecting persons within their range allows the server to distinguish violations of set security rules and trigger a predefined action, such as an audible alarm. It is obvious that security rules can be chosen very arbitrarily with regard to the requirements of a particular application. Examples of security policy violations include:

• The presence of a person detected by the PIR sensor in an area where there is no locator entrusted to an authorized person.

• The presence of a locator in an area to which the person to whom the locator has been entrusted does not have permission to enter.

Example 2

An exemplary embodiment of a location security system according to claim 5 consists of a server 6, three or more static sensor units 7 and locators 3.

The sensor units 7 comprise, in contrast to the sensor units 1, a wireless communication interface 8, which is preferably used for communication of the sensor units with the server without the need to use UWB radio for this communication. An example of such an interface is Wi-Fi or Bluetooth. In other respects, this system is equivalent to Example 1.

Example 3

An exemplary embodiment of a location security system according to claim 5 consists of a server 6, three or more static sensor units 9 and locators 3.

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The sensor units 9 comprise, in contrast to the sensor units 1, a cable communication interface 10, which is preferably used for communication of the sensor units with the server without the need to use UWB radio for this communication. An example of a cable interface is Ethernet, RS-485/422, CAN bus. In other respects, this system is equivalent to Example 1.

Example 4

An exemplary embodiment of a location security system according to claim 5 consists of a server 6, three or more static sensor units 11 and locators 3.

The sensor units 11 comprise, in addition to the sensor units 1, an additional sensor for detecting the presence of persons 12, preferably operating on a principle other than PIR, which serves to prevent false alarms. In other respects, this system is equivalent to Example 1.

It is clear that in Examples 1 to 4 it is possible to combine sensor units 1, 7, 9 and 11 within one system according to the requirements of a specific application.

Example 5

An exemplary embodiment of a location security system according to claim 6 consists of a server 6, three or more static sensor units 1, 7, or 9 and locators 3.

The static sensor units are arranged in the guarded area so that the PIR sensors 4 cover the areas of the guarded area in which the presence of unauthorized persons must be detected and at the same time that the guarded area is sufficiently covered by the UWB signal. Eoquators 3 periodically send short messages using UWB radio, which contain a locator identifier. The messages are received by the sensor units, which record the time stamp of the moment the message is received from the locator. The time stamps and the locator identifier are sent from the static sensor units to the server, where the position of the locators is calculated using the TDOA (Time Difference Of Arrival) method. Static sensor units also send signals from PIR sensors to the server. The exact location of the locators and the signals from the PIR sensors are used as in Example 1. The use of the TDOA method requires that the sensor units be time synchronized, for example using the known methods given in [Comparison of wireless clock synchronization algorithms for indoor location systems, DOI: 10.1109 / ICCW.2014.6881189].

Example 6

An exemplary embodiment of a location security system according to claim 7 consists of a server 6, three or more static sensor units 1, 7, or 9 and locators 3.

The difference from Example 5 is that instead of the TDOA method, the A-TDOA (Asynchronous TDOA) method is preferably used. The advantage of using the A-TDOA method is that the sensor units do not have to be time-synchronized.

Example 7

An exemplary embodiment of the static sensor unit 1 according to claim 1 comprises a UWB radio using a DEC1WAVE DW1000 integrated circuit. In a preferred embodiment, the DWM1000 module can be used, which integrates the DW1000 circuit, the antenna and the auxiliary circuits.

Claims (7)

PROTECTION REQUIREMENTS A location security system with at least three static sensor units, characterized in that the static sensor unit (1) of the location security system comprises at least one radio receiver / transmitter (2) with an ultra-wide 500 MHz frequency band for receiving / transmitting a signal from / to the locator (3), which is part of the location security system and which is designed to communicate with static sensor units to distinguish the arrival time of the broadband signal to the receiver / transmitter (2) with a resolution of at least 15 ps, and at least one passive infrared sensor ( 4) for detecting the presence of persons in the controlled area and further at least one control chip (5) for processing incoming signals and for communication with the server (6), which is part of the location security system. Location security system with at least three static sensor units according to claim 1, characterized in that the static sensor unit (7) comprises a wireless communication interface (8) for communication with the server (6). Location security system with at least three static sensor units according to claim 1, characterized in that the static sensor unit (9) comprises a cable communication interface (10) for communication with the server (6). The location security system with at least three static sensor units according to claim 1, characterized in that the static sensor unit (11) comprises a further person presence sensor (12). The location security system with at least three static sensor units according to claim 1, characterized in that the at least one static sensor unit of the location security system is a unit selected from the group of units (1), (7), (9), (11), which are designed to measure the distance from the locators (3) by the Two Way Ranging method by means of a radio receiver / transmitter (2), and the location security system further comprises at least one locator (3) for communication with static sensor units by means of a radio receiver / transmitter (2). for determining the distance by the Two Way Ranging method, wherein at least one server (6) is provided for receiving a signal from the static sensor units of the measured distance between them and the at least one locator (3), and for receiving a signal from the static sensor units of passive infrared sensor signals ( 4) static sensor units for calculating the position of the locators (3) based on the received distances of the locators and units static sensor units and for the evaluation of the detected presence of persons and the position of the locators (3) with respect to the predefined security conditions of the monitored areas. Location security system according to claim 5, characterized in that the static sensor units are time-synchronized, the locators (3) are designed to transmit short messages at periodic intervals which contain a locator identifier and are detectable by a radio transceiver (2). of static sensor units in the signal range, the server (6) is designed to receive the signal from the static sensor units of the time stamp of receiving messages from the locators (3) and to calculate the position of the locators (3) based on the received time stamps by the Time Difference of Arrival method. Location security system according to claim 5, characterized in that the static sensor units and locators (3) are designed for communication with each other within the Asynchronous Time Difference of Arrival method, and the server (6) is designed to calculate the position of the locators (3). ) based on time stamp differences received by the Asynchronous Time Difference of Arrival method.