CZ2020295A3 - Location security system with at least three static sensor units - Google Patents

Abstract

The location security system with at least three static sensor units operating in real time using sensor units contains, among other things, PIR sensors for detecting the movement of people and UWB radio for accurate location.

Description

Location security system with at least three static sensor units

Field of technology

The invention relates to the field 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 significantly increasing. 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

-1 CZ 2020 - 295 A3 principle, in order to sound an alarm it is necessary to meet the condition of detecting the movement of a person from both or more sensors. 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.

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 invention

The essence of the invention 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 a direct visibility of 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.

- 2 CZ 2020 - 295 A3

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.

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

-3GB 2020 - 295 A3

Examples of embodiments of the invention

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 the locators using the TWR method using the UWB radio (2). The UWB radio sensor units are also used to send measured distances from locators and PIR sensor signals to the server (6). From the received distance data, the exact position of the locators and thus the authorized persons to whom the locators have been entrusted is calculated in the server. 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 between the sensor units and 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).

-4EN 2020 - 295 A3

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. The locators (3) periodically send short messages using the UWB radio, which contain the 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).

-5GB 2020 - 295 A3

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 a 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)

PATENT CLAIMS 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) using the ultra-wide frequency band 500 MHz (UWB radio), which is used to receive the locator signal (3) and which is able to distinguish the arrival time of a broadband signal with a resolution of at least 15 ps and at least one passive infrared sensor (PIR) (4), used to detect the presence of persons in the controlled area and at least one control chip (5) for processing incoming signals and 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 (7) comprises all components of the unit (1) and further 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 all components of the unit (1) or (7) and further comprises a cable communication interface (10) for communication with 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 all components of the unit (1) or (7) or (9) and further comprises a further person presence sensor ( 12). A location security system with at least three static sensor units, characterized in that the at least one static sensor unit of the location security system is a unit (1) and / or (7) and / or (9) and / or (11), which measures the distance from the locators (3) using the "Two Way Ranging" method (hereinafter TWR) using UWB radio (2) and the location security system further contains at least one locator (3), which communicates with static sensor units using UWB radio (2) determination of the distance using the "Two Way Ranging" method, whereby at least one server (6) receives from the static sensor units the measured distances between them and at least one locator (3), further -7 CZ 2020 - 295 A3 receives signals from PIR sensors of static sensor units from static sensor units, calculates position of locators (3) based on received distances of locators and individual static sensor units and evaluates detected presence of persons and position of locators (3) due 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) transmit short messages at periodic intervals which contain the locator identifier and are detectable by the UWB radio (2) of the static sensor units within signal range. , the server (6) receives from the static sensor units time stamps the reception of messages from the locators (3) and calculates the position of the locators (3) on the basis of the time stamps received by the "Time Difference of Arrival" (TDOA) method. Location security system according to claim 5, characterized in that the static sensor units and locators (3) communicate with each other within the "Asynchronous Time Difference is of Arrival" (A-TDOA) method and the server (6) calculates the position of the locators (3) Based on Asynchronous Time Difference of Arrival (A-TDOA) received time stamp differences.