Monitoring method, device and intrusion alarm system

Abstract

The present invention discloses a monitoring method, device and intrusion alarm system, which includes a controller, a signal transmitting device and three or more signal receiving devices. The signal transmitting device is installed on the monitored intrusion target, and multiple signal receiving devices are installed at preset positions in the monitoring area to form a triangle or a triangular cone in three-dimensional space. The signal transmitting device sends a wireless signal to the outside in real time, and the signal receiving device receives the signal and controls the real-time transmission of the wireless signal. When the controller identifies that the RSSI value of the wireless signal exceeds the corresponding set threshold, the controller starts to run a spatial triangulation positioning algorithm, obtains the coordinates of the signal transmitting device based on the known coordinates of the three or more signal receiving devices, and combines the size and layout of the monitoring area to determine whether the intrusion target is within the monitoring area. When the intrusion target is within the monitoring area, the controller generates an alarm message, and the alarm message includes position and time information.

Description

Technical Field

[0001] The present invention relates to the field of intrusion alarms, and in particular to a monitoring method, device and intrusion alarm system. Background Art

[0002] Currently, electric bicycles pose a safety hazard when used in elevators in residential and commercial buildings. A short circuit or overcharge in an electric bicycle or its battery can cause a fire or other safety incident. Currently, many visual recognition technologies are used to identify electric bicycles in elevator cabins, thereby preventing them from entering. However, due to the diverse items carried by elevator passengers and the obstruction of visual recognition due to the large number of passengers, visual recognition methods for preventing electric bicycles from entering the cabin have drawbacks, often resulting in misjudgments or missed detections. Furthermore, visual recognition cannot prevent passengers from taking disassembled electric bicycles into elevators to go upstairs. The fire hazard lies in the battery of an electric bicycle. Therefore, developing a new monitoring method, device, and intrusion alarm system that can effectively identify and prevent electric bicycles or disassembled batteries from entering elevators is of great practical significance. This technology also needs to balance accuracy with production costs and be applicable to a wider range of scenarios. Summary of the Invention

[0003] To solve the above problems, the present invention provides a monitoring method, device and intrusion alarm system. The signal receiving device cooperates with the signal transmitting device to obtain the RSSI value in real time. The RSSI value more accurately determines the position distance between the signal transmitting device and the signal receiving device. When the controller recognizes that the RSSI value of the wireless signal exceeds the corresponding set threshold, the controller starts to run the spatial triangulation positioning algorithm. The controller obtains the coordinates of the signal transmitting device through the spatial triangulation positioning algorithm, and then combines the size and layout of the monitoring area to accurately and quickly determine whether the intrusion template is within the monitoring area.

[0004] The technical solution adopted by the present invention is: an intrusion alarm system, including a controller, a signal transmitting device and three or more signal receiving devices, the signal transmitting device is installed on the monitored intrusion target, and the three or more signal receiving devices are installed at preset positions in the monitoring area to form a triangle or a triangular cone in three-dimensional space. The controller and the signal receiving device are connected, the signal transmitting device sends a wireless signal to the outside in real time, the signal receiving device receives the signal and the controller transmits the wireless signal in real time. When the controller identifies that the RSSI value of the wireless signal exceeds the corresponding set threshold, the controller starts to run a spatial triangulation positioning algorithm, obtains the coordinates of the signal transmitting device based on the known coordinates of the three or more signal receiving devices, and combines the size and layout of the monitoring area to determine whether the intrusion target is within the monitoring area. When the intrusion target is within the monitoring area, the controller generates an alarm message, and the alarm message includes location and time information;

[0005] The RSSI threshold is set according to the shortest distance from the signal receiving device to the monitoring area and the distance formula. The distance formula is:

[0006] ;

[0007] Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device; RSSI is the RSSI value currently received by the signal receiving device; and n is the environmental attenuation factor.

[0008] Furthermore, the monitored intrusion target is an electric bicycle or its battery. The signal transmitting device adopts the nRF52 series Bluetooth module, and the signal receiving device adopts the CC2640R2F Bluetooth gateway module. The signal transmitting device is installed inside the battery shell of the electric bicycle, and the signal receiving device is located on the car wall on multiple different sides of the car.

[0009] Furthermore, the controller of the present application is also connected to the elevator control system. The elevator operation system is connected to a travel controller in the shaft on the first floor or the underground floor. When the elevator car touches the travel switch of the floor, it indicates that the elevator has reached the floor. When the elevator reaches the floor, it sends a start signal to the elevator system and transmits the signal to the controller. The controller forwards the start signal to the signal receiving device, and the signal receiving device starts to receive the signal sent by the signal transmitting device.

[0010] Furthermore, the signal transmitting device specifically adopts nRF52840, including two crystal oscillator circuits, wherein the first crystal oscillator circuit includes crystal oscillator X1, C1 and C2, one end of capacitor C1 is connected to the XL1 interface of nRF52840, one end of capacitor C2 is connected to the XL2 interface of nRF52840, the other ends of capacitors C1 and C2 are both grounded, and crystal oscillator X1 is connected between one end of capacitor C1 and one end of capacitor C2; the second crystal oscillator circuit includes crystal oscillator X2, capacitors C3 and C4, one end of capacitor C3 is connected to the XC2 interface of nRF52840, one end of capacitor C4 is connected to the XC1 interface of nRF52840, the other ends of capacitors C3 and C4 are both grounded, and crystal oscillator X2 is connected between one end of capacitor C3 and one end of capacitor C4. The two crystal oscillator circuits are divided into generating high-speed clock and low-speed clock.

[0011] The present invention also provides a monitoring method, which is applied to a controller of an intrusion alarm system and comprises the following steps:

[0012] S1: When the controller identifies that the RSSI value received by the signal receiving device exceeds the corresponding set threshold, the controller starts to run the spatial triangulation positioning algorithm;

[0013] S2: The three signal receiving devices are respectively denoted as A, B and C, and the position coordinates of three or more known signal receiving devices are obtained. The position coordinates are respectively expressed as ( , )、( , )as well as( , ), the position coordinates of the signal transmitter are assumed to be (x, y), A, B and C respectively measure the RSSI values from the signal transmitter, and calculate the three RSSI values according to the distance formula and convert them into distance 、 、 , the distance formula is:

[0014]

[0015] Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device; RSSI is the RSSI value currently received by the signal receiving device; and n is the environmental attenuation factor.

[0016] S3: List the following equations and solve them using Newton's iteration method to obtain the position coordinates (x, y) of the signal transmitter:

[0017] ;

[0018] ;

[0019] = ;

[0020] S4: The controller determines whether the signal transmitter is within the monitoring area of the car based on the calculated position coordinates (x, y) of the signal transmitter and the boundary coordinates of the monitoring area of the car. When it is determined that the signal transmitter is within the monitoring area of the car, the controller generates an alarm message, which includes position and time information.

[0021] Furthermore, in step S3, the steps of solving the equation system are as follows:

[0022] S31: Write the system of equations in functional form:

[0023] ;

[0024] ;

[0025] ;

[0026] List the iterative formula of Newton's iteration method: ,in, is the Jacobian matrix, is a function vector;

[0027] List the Jacobian matrix:

[0028] [ ]

[0029] [ ]

[0030] [ ]

[0031] The function vector F consists of the individual function values:

[0032] ;

[0033] ;

[0034] ;

[0035] Compute partial derivatives: ;

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] ;

[0041] S32: Select an initial guess point , substitute the Jacobian matrix and function vector F listed in step S31 into the formula to calculate the Jacobian matrix and function vector ;

[0042] S33: Based on step S32, solve the linear equations ,get = [ , ];

[0043] S34: Update iteration point: = ;

[0044] S35: Repeat steps S32-S34 until the convergence condition is met ,in is any positive number.

[0045] Furthermore, it also includes step S5: the controller is connected to the centralized monitoring center of the building property. When the controller confirms that the intrusion target appears in the monitoring area, the controller generates an alarm message, and the alarm message includes location and time information. The controller sends the location and time information to the centralized monitoring center in a timely manner.

[0046] Furthermore, step S6 is also included: the controller is also connected to the elevator control system, the elevator control system is connected to at least one sound alarm, and the sound alarm is set in the shaft on the first floor or the underground floor. When the controller confirms that the intrusion target appears in the monitoring area, it sends an intrusion signal to the elevator control system, the elevator operation system controls the elevator not to start, the elevator control system stops the elevator from running up or down, and the sound alarm sounds an alarm to remind the intrusion target to stay away from the monitoring area until the controller confirms that there is no intrusion target in the monitoring area and then continues normal operation.

[0047] The present invention also provides a monitoring device, which is applied to a controller of an intrusion alarm system, and the device comprises:

[0048] The laser radar is connected to the controller and is used to scan the three-dimensional area around the monitoring area. The controller crops and splices the acquired scan data to obtain the boundary coordinates of the surrounding three-dimensional area;

[0049] A first calculation module is used to substitute the shortest distance between multiple signal receiving devices and the boundary of the monitoring area into the distance formula to obtain the RSSI value threshold of the corresponding signal receiving device;

[0050] The first judgment module is used to judge whether the RSSI values currently received by the multiple signal receiving devices are greater than the corresponding set thresholds. If the RSSI value of any signal receiving device is greater than the set threshold, the spatial triangulation positioning algorithm is started;

[0051] A second calculation module is used to calculate the position coordinates of the signal transmitting device based on the position coordinates of the multiple signal receiving devices through spatial triangulation calculation;

[0052] The second judgment module is used to judge whether the position coordinates of the signal transmitting device fall within the monitoring area according to the boundary coordinate values of the monitoring area preset in advance;

[0053] The generation module generates an alarm message including the location and time information of the signal transmitter when confirming that the location coordinates of the signal transmitter fall into the monitoring area.

[0054] The present application provides a monitoring method, device, and electric vehicle intrusion alarm system. Based on RSSI values and a triangular space algorithm, the system can accurately identify whether there is an intruder in the monitoring area. The system has a simple structure and an uncomplicated algorithm. The position coordinates of the signal transmitter can be quickly calculated. Combined with the preset three-dimensional boundary coordinate data of the monitoring area of the elevator car, the system can quickly determine whether the intruder is in the elevator car. The judgment method is accurate and fast, and is not limited to ground monitoring. It can be applied to intrusion detection in various complex environments. Ground coordinates are generally limited to plane coordinates. The provision of three or more signal receiving devices can achieve multi-directional monitoring of intruders. The signal receiving device and the signal transmitting device replace the traditional method of detecting the presence of intruders in the elevator through image or visual recognition. The system has higher accuracy and is still applicable to people who deliberately hide intruders without misjudgment. The system is particularly suitable for applications in some situations where it is difficult to identify through a visual system or when there is a hidden intrusion, thereby increasing the safety and reliability of the intrusion alarm system. The controller starts the algorithm after the RSSI value reaches a threshold, which can avoid the controller being constantly in complex calculations, reducing energy consumption and improving energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the installation of the signal transmitting device according to embodiment 1 of the present invention.

[0056] Figure 2 This is a schematic diagram of the installation of the signal receiving device according to embodiment 1 of the present invention.

[0057] Figure 3 This is a schematic diagram of the chip principle of the signal receiving device according to embodiment 1 of the present invention.

[0058] Figure 4 This is a flowchart of Example 3 of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and a preferred embodiment. Example 1

[0060] Embodiment 1 of the present application provides an intrusion alarm system, which includes a controller, a signal transmitting device, and three or more signal receiving devices. The signal transmitting device is installed on the monitored intrusion target, and the three or more signal receiving devices are installed at preset positions in the monitoring area to form a triangle or a triangular cone in three-dimensional space. The controller and the signal receiving device are connected. The signal transmitting device sends a wireless signal to the outside in real time, and the signal receiving device receives the signal and transmits the wireless signal to the controller in real time. When the controller identifies that the RSSI value of the wireless signal exceeds the corresponding set threshold, the controller starts to run a spatial triangulation positioning algorithm, obtains the coordinates of the signal transmitting device based on the known coordinates of the three or more signal receiving devices, and combines the size and layout of the monitoring area to determine whether the intrusion target is within the monitoring area. When the intrusion target is within the monitoring area, the controller generates an alarm message, and the alarm message includes location and time information;

[0061] The RSSI threshold is set according to the shortest distance from the signal receiving device to the monitoring area and the distance formula. The distance formula is:

[0062]

[0063] Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device, which needs to be obtained through experimental measurement; RSSI is the RSSI value currently received by the signal receiving device; and n is the environmental attenuation factor, which is usually between 2 and 4 and the specific value needs to be determined according to the actual environment.

[0064] The monitored intrusion target in Example 1 of the present application is an electric bicycle or its battery, the monitoring area is the elevator cabin space, the signal transmitting device adopts the nRF52 series Bluetooth module, and the signal receiving device adopts the highly sensitive CC2640R2F Bluetooth gateway module. Figure 1 The signal transmitting device is installed inside the battery shell of the electric bicycle, and it is inconvenient to remove the signal transmitting device. Therefore, even if the electric bicycle user removes the battery and takes it into the elevator, it will be identified. The signal receiving device is installed in the elevator car and can be located at least one of the top, middle, and bottom of the car. In this embodiment, there are three signal receiving devices, which are located on the walls of three different sides of the car to form a triangle or a triangular pyramid in three-dimensional space.

[0065] refer to Figure 2In Example 1 of the present application, the three signal receiving devices are arranged on the innermost side and left and right sides of the car, namely A, B and C. The shortest distance between the three signal receiving devices and the boundary area of the car is assumed to be d, or the size of d is adjusted according to needs. The RSSI reference value of the signal receiving device 1 meter away from the signal transmitting device is measured, and the RSSI value is calculated according to the distance formula. This RSSI value is the threshold.

[0066] In specific applications, the staff can determine the number of signal receiving devices to be set and the position of each signal receiving device based on the surrounding three-dimensional area of the monitored area and the scanning range of the signal receiving device and the signal transmitting device to achieve the best recognition effect.

[0067] Specifically, in this embodiment, the method for obtaining the boundary position coordinates of the monitoring area is: the three-dimensional area surrounding the monitoring area is scanned by a laser radar, and the controller crops and splices the acquired scanning data to obtain spatial data of the surrounding three-dimensional area. The data obtained by this method is more accurate.

[0068] The controller of Example 1 of the present application is connected to the centralized monitoring center of the building property. When the controller confirms that the intrusion target appears in the monitoring area, the location and time information is sent to the centralized monitoring center in a timely manner. The staff of the centralized monitoring center can adjust the monitoring video according to the location and time, find the target resident as soon as possible, and remind them to take the intrusion target out of the building.

[0069] The controller of the present application is also connected to the elevator control system, and the elevator control system is connected to at least one sound alarm. The sound alarm is set in the shaft on the first floor or the underground floor. An sound alarm can also be set on each floor according to actual needs. The elevator control system is programmable for each elevator. When the controller confirms that the intrusion target appears in the monitoring area, it sends an intrusion signal to the elevator control system. The elevator's operating system controls the elevator not to start, and the elevator control system stops the elevator from running up or down. The sound alarm also sounds an alarm to remind the intrusion target to stay away from the monitoring area until the controller confirms that there is no intrusion target in the monitoring area and continues normal operation.

[0070] In some other embodiments, the elevator operation system of the present application is connected to a travel controller in the shaft on the first floor or the underground floor. When the elevator car touches the travel switch of the floor, it indicates that the elevator has reached the floor. When the elevator reaches the floor, a start signal is sent to the elevator system and the signal is transmitted to the controller. The controller forwards the start signal to the signal receiving device. Only then does the signal receiving device start to receive the signal sent by the signal transmitting device. The present application mainly prevents electric vehicles or batteries from being brought into the building to prevent misjudgment, such as when residents in the building take electric vehicles or batteries out by taking the elevator.

[0071] refer to Figure 3 The signal transmitter device in this application utilizes the nRF52 series Bluetooth module, specifically the nRF52840, which features a 32-bit ARM Cortex-M4 processor. This processor offers powerful computing capabilities, low power consumption, large memory, excellent stability, and a long communication range. The nRF52840 operates from a 1.7V-5.5V power supply. This embodiment uses an external DC power supply (VDDH) interface connected to a 5V power adapter for power. The nRF52840 includes two crystal oscillator circuits, where the first crystal oscillator circuit includes crystal oscillator X1, C1 and C2. One end of capacitor C1 is connected to the XL1 interface of the nRF52840, one end of capacitor C2 is connected to the XL2 interface of the nRF52840, the other ends of capacitors C1 and C2 are both grounded, and crystal oscillator X1 is connected between one end of capacitor C1 and one end of capacitor C2; the second crystal oscillator circuit includes crystal oscillator X2, capacitors C3 and C4, one end of capacitor C3 is connected to the XC2 interface of the nRF52840, one end of capacitor C4 is connected to the XC1 interface of the nRF52840, the other ends of capacitors C3 and C4 are both grounded, and crystal oscillator X2 is connected between one end of capacitor C3 and one end of capacitor C4. The two crystal oscillator circuits are divided into generating high-speed clock and low-speed clock.

[0072] The intrusion alarm system provided by the present application replaces the traditional method of detecting whether there are electric vehicles in the elevator through image recognition by using a signal receiving device and a signal transmitting device. It has higher accuracy and is still applicable to people who deliberately hide electric vehicles or batteries, and there will be no misjudgment. Based on the RSSI value and the triangular space algorithm, it can accurately identify whether there are intrusion targets in the monitored area. The algorithm is started after the RSSI value reaches the threshold, which can avoid the controller being in complex calculations all the time, reduce energy consumption and improve energy utilization efficiency. It adopts the nRF52 series Bluetooth module with high receiving sensitivity, ultra-large memory and flexible power management, which further increases the accuracy of the system and the battery durability and life.

[0073] The present application also provides a monitoring method, which is applied to the controller of the intrusion alarm system in Example 1. The controller can be an electronic device with computing functions. The intrusion alarm system includes a signal transmitting device and three or more signal receiving devices.

[0074] The monitoring method includes the following steps:

[0075] S1: When the controller identifies that the RSSI value received by the signal receiving device exceeds the corresponding set threshold, the controller starts to run the spatial triangulation positioning algorithm;

[0076] S2: The three signal receiving devices are respectively denoted as A, B and C, and the position coordinates of three or more known signal receiving devices are obtained. The position coordinates are respectively expressed as ( , )、( , )as well as( , ), the position coordinates of the signal transmitter are assumed to be (x, y), A, B and C respectively measure the RSSI values from the signal transmitter, and calculate the three RSSI values according to the distance formula and convert them into distance 、 、 , the distance formula is;

[0077]

[0078] Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device, which needs to be obtained through experimental measurement; RSSI is the RSSI value currently received by the signal receiving device; and n is the environmental attenuation factor, which is usually between 2 and 4 and the specific value needs to be determined according to the actual environment.

[0079] S3: List the following equations and solve them using Newton's iteration method to obtain the position coordinates (x, y) of the signal transmitter:

[0080] ;

[0081] ;

[0082] = ;

[0083] S4: The controller determines whether the signal transmitter is within the monitoring area of the car based on the calculated position coordinates (x, y) of the signal transmitter and the boundary coordinates of the monitoring area of the car. When it is determined that the signal transmitter is within the monitoring area of the car, the controller generates an alarm message, which includes position and time information.

[0084] Specifically, in the above step S3, the steps of solving the equation system are as follows:

[0085] S31: Write the system of equations in functional form:

[0086] ;

[0087] ;

[0088] ;

[0089] List the iterative formula of Newton's iteration method: ,in, is the Jacobian matrix, is a function vector.

[0090] List the Jacobian matrix:

[0091] [ ]

[0092] [ ]

[0093] [ ]

[0094] The function vector F consists of the individual function values:

[0095] ;

[0096] ;

[0097] ;

[0098] Compute partial derivatives: ;

[0099] ;

[0100] ;

[0101] ;

[0102] ;

[0103] ;

[0104] S32: Select an initial guess point , bring it into the Jacobian matrix and function vector formula listed in step S31, and calculate the Jacobian matrix and function vector ;

[0105] S33: Based on step S32, solve the linear equations ,get =[ , ];

[0106] S34: Update iteration point: = ;

[0107] S35: Repeat steps S32-S34 until the convergence condition is met ,in is any positive number.

[0108] In some other embodiments, in order to improve the positioning accuracy of the signal transmitting device, multiple RSSI measurements are performed on each Bluetooth transmitter to reduce errors. After the position of the receiver R is calculated, it is determined whether the Bluetooth receiver is within the elevator car position range.

[0109] Furthermore, this embodiment also includes step S5: the controller is connected to the centralized monitoring center of the building property. When the controller confirms that the intrusion target appears in the monitoring area, the controller generates an alarm message, and the alarm message includes location and time information. The controller sends the location and time information to the centralized monitoring center in a timely manner. The staff of the centralized monitoring center can adjust the surveillance video according to the location and time, find the target resident as soon as possible, and remind them to take the intrusion target out of the building.

[0110] Furthermore, this embodiment also includes step S6: the controller is also connected to the elevator control system, the elevator control system is connected to at least one sound alarm, and the sound alarm is set in the shaft on the first floor or the underground floor. When the controller confirms that the intrusion target appears in the monitoring area, it sends an intrusion signal to the elevator control system, the elevator operation system controls the elevator not to start, the elevator control system stops the elevator from running up or down, and the sound alarm sounds an alarm. The specific alarm content is: electric bicycles are not allowed to enter the elevator to remind the intrusion target to stay away from the monitoring area. Until the controller confirms that there is no intrusion target in the monitoring area, it will continue to operate normally.

[0111] Through the monitoring method of the present application, in combination with the intrusion alarm system of Example 1, the position coordinates of the signal transmitting device can be quickly calculated. Combined with the preset boundary coordinate points of the monitoring area of the car, it can be quickly determined whether the intrusion target is in the car. The judgment method is accurate and fast. If an intrusion target is determined, an alarm can be sent to the property's centralized monitoring center in the first time, and the elevator can also be stopped from running up or down, and the sound alarm can be sounded to avoid the situation where the property staff cannot arrive at the scene in time and stop the passengers. Example 3

[0112] refer to Figure 4 The present application further provides a monitoring device, which is applied to the intrusion alarm system described in Example 1. The intrusion alarm system includes a signal transmitting device and three or more signal receiving devices. The monitoring device includes:

[0113] The laser radar is connected to the controller. The laser radar is used to scan the three-dimensional area around the monitoring area to obtain scanning data. The controller crops and splices the obtained scanning data to obtain the boundary coordinates of the surrounding three-dimensional area, and pre-stores the boundary coordinate values in the controller;

[0114] A first calculation module is used to substitute the shortest distance between multiple signal receiving devices and the boundary of the monitoring area into the distance formula to obtain the RSSI value threshold of the corresponding signal receiving device;

[0115] The first judgment module is used to judge whether the RSSI values currently received by the multiple signal receiving devices are greater than the corresponding set thresholds. When the RSSI value of any signal receiving device is greater than its corresponding set threshold, the spatial triangulation positioning algorithm is started;

[0116] A second calculation module is used to calculate the position coordinates of the signal transmitting device based on the position coordinates of the multiple signal receiving devices through spatial triangulation calculation;

[0117] The second judgment module is used to judge whether the position coordinates of the current signal transmitting device fall within the monitoring area according to the boundary coordinate values of the monitoring area preset in advance;

[0118] The generation module generates an alarm message including the location and time information of the transmitter when confirming that the location coordinates of the signal transmitter fall within the monitoring area.

[0119] Furthermore, the monitoring device also includes a communication module, which is used to transmit alarm information to a connected monitoring center.

[0120] Furthermore, the monitoring device also includes an alarm module and an emergency stop module. The alarm module is used for warning, and the emergency stop module is used for stopping the operation of part of the equipment in the monitoring area.

[0121] The monitoring device provided by the present application has a signal transmitting device arranged on the intrusion target, the signal transmitting device transmits the signal in real time, the signal receiving device receives the identification signal in real time, and the signal receiving device receives the RSSI value in real time. If the RSSI value of any signal receiving device is greater than the set threshold, the spatial triangulation positioning algorithm is started to run to realize multi-directional monitoring of the intrusion target. The spatial triangulation positioning algorithm can accurately identify the position coordinates of the intrusion target. Once the intrusion target is identified, an alarm message can be generated and sent to the monitoring center. The device has a simple structure, a simple algorithm, and a very low cost. It realizes intrusion monitoring and alarm, and is particularly suitable for use in some occasions that are not easy to identify through a visual system, or in the presence of hidden intrusions, thereby increasing the safety and reliability of the intrusion alarm system.

[0122] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also within the scope of protection of the present invention.

Claims

1. An intrusion alarm system, characterized in that: The system includes a controller, a signal transmitter and three or more signal receiving devices. The signal transmitter is installed on the monitored intrusion target, and the three or more signal receiving devices are installed at preset positions in the monitoring area to form a triangle or a triangular cone in three-dimensional space. The controller and the signal receiving device are connected. The signal transmitter sends a wireless signal to the outside in real time, and the signal receiving device receives the signal and transmits the wireless signal to the controller in real time. When the controller identifies that the RSSI value of the wireless signal exceeds the corresponding set threshold, the controller starts to run a spatial triangulation positioning algorithm, obtains the coordinates of the signal transmitter based on the known coordinates of the three or more signal receiving devices, and combines the size and layout of the monitoring area to determine whether the intrusion target is within the monitoring area. When the intrusion target is within the monitoring area, the controller generates an alarm message, and the alarm message includes location and time information; The RSSI threshold is set according to the shortest distance from the signal receiving device to the monitoring area and the distance formula. The distance formula is: ； Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device; RSSI is the RSSI value currently received by the signal receiving device; n is the environmental attenuation factor; The system also includes a laser radar, which is connected to a controller and is used to scan a three-dimensional area surrounding the monitoring area. The controller crops and splices the acquired scan data to obtain the boundary coordinates of the surrounding three-dimensional area. The shortest distance between multiple signal receiving devices and the boundary of the monitoring area is substituted into the distance formula to obtain the RSSI value threshold of the corresponding signal receiving device. The monitored intrusion target is an electric bicycle or its battery. The signal transmitter uses the nRF52 series Bluetooth module, and the signal receiver uses the CC2640R2F Bluetooth gateway module. The signal transmitter is installed inside the electric bicycle battery shell, and the signal receiver is located on multiple different sides of the car wall. The controller is also connected to the elevator control system. The elevator operation system is connected to a travel controller in the shaft on the first floor or the underground floor. When the elevator car touches the travel switch of the floor, it means that the elevator has reached that floor. When the elevator reaches that floor, it sends a start signal to the elevator system and transmits the signal to the controller. The controller forwards the start signal to the signal receiving device, and the signal receiving device starts to receive the signal sent by the signal transmitting device.

2. An intrusion alarm system according to claim 1, characterized in that: The signal transmitting device specifically adopts nRF52840 and includes two crystal oscillator circuits, wherein the first crystal oscillator circuit includes crystal oscillator X1, C1 and C2, one end of capacitor C1 is connected to the XL1 interface of nRF52840, one end of capacitor C2 is connected to the XL2 interface of nRF52840, the other ends of capacitors C1 and C2 are both grounded, and crystal oscillator X1 is connected between one end of capacitor C1 and one end of capacitor C2; the second crystal oscillator circuit includes crystal oscillator X2, capacitors C3 and C4, one end of capacitor C3 is connected to the XC2 interface of nRF52840, one end of capacitor C4 is connected to the XC1 interface of nRF52840, the other ends of capacitors C3 and C4 are both grounded, and crystal oscillator X2 is connected between one end of capacitor C3 and one end of capacitor C4. The two crystal oscillator circuits are divided into generating high-speed clock and low-speed clock.

3. A monitoring method, applied to the controller of the intrusion alarm system according to any one of claims 1-2, characterized in that: The steps include: S1: When the controller identifies that the RSSI value received by the signal receiving device exceeds the corresponding set threshold, the controller starts to run the spatial triangulation positioning algorithm; S2: The three signal receiving devices are respectively denoted as A, B and C, and the position coordinates of three or more known signal receiving devices are obtained. The position coordinates are respectively expressed as ( , )、( , )as well as( , ), the position coordinates of the signal transmitter are assumed to be (x, y), A, B and C respectively measure the RSSI values from the signal transmitter, and calculate the three RSSI values according to the distance formula and convert them into distance 、 、 , the distance formula is: ； Where d is the distance between the signal receiving device and the signal transmitting device; RSSI0 is the RSSI reference value when the signal receiving device is 1 meter away from the signal transmitting device; RSSI is the RSSI value currently received by the signal receiving device; n is the environmental attenuation factor; S3: List the following equations and solve them using Newton's iteration method to obtain the position coordinates (x, y) of the signal transmitter: ； ； = ； S4: The controller determines whether the signal transmitter is within the monitoring area of the car based on the position coordinates (x, y) of the signal transmitter obtained in step S3 and the boundary coordinates of the monitoring area of the car. When it is determined that the signal transmitter is within the monitoring area of the car, the controller generates an alarm message, which includes position and time information.

4. A monitoring method according to claim 3, characterized in that: In the above step S3, the steps of solving the equation system are as follows: S31: Write the system of equations in functional form: ； ； ； List the iterative formula of Newton's iteration method: ; in, is the Jacobian matrix, is a function vector; List the Jacobian matrix: [ ] [ ] [ ] The function vector F consists of the individual function values: ； ； ； Compute partial derivatives: ; ； ； ； ； ； S32: Select an initial guess point , substitute the Jacobian matrix and function vector F listed in step S31 into the formula to calculate the Jacobian matrix and function vector ; S33: Based on step S32, solve the linear equations ,get = [ , ]; S34: Update iteration point: = ; S35: Repeat steps S32-S34 until the convergence condition is met ,in is any positive number.

5. A monitoring method according to claim 3, characterized in that: It also includes step S5: the controller is connected to the centralized monitoring center of the building property. When the controller confirms that the intrusion target appears in the monitoring area, the controller generates an alarm message, which includes location and time information. The controller sends the location and time information to the centralized monitoring center in a timely manner.

6. A monitoring method according to claim 3, characterized in that: It also includes step S6: the controller is also connected to the elevator control system, the elevator control system is connected to at least one sound alarm, and the sound alarm is set in the shaft on the first floor or the underground floor. When the controller confirms that the intrusion target appears in the monitoring area, it sends an intrusion signal to the elevator control system, the elevator operation system controls the elevator not to start, the elevator control system stops the elevator from running up or down, and the sound alarm sounds an alarm to remind the intrusion target to stay away from the monitoring area. The controller will not continue to operate normally until it confirms that there is no intrusion target in the monitoring area.

7. A monitoring device, applied to the controller of the intrusion alarm system according to any one of claims 1-2, characterized in that: The device includes: The laser radar is connected to the controller and is used to scan the three-dimensional area around the monitoring area. The controller crops and splices the acquired scan data to obtain the boundary coordinates of the surrounding three-dimensional area; A first calculation module is used to substitute the shortest distance between multiple signal receiving devices and the boundary of the monitoring area into the distance formula to obtain the RSSI value threshold of the corresponding signal receiving device; The first judgment module is used to judge whether the RSSI values currently received by the multiple signal receiving devices are greater than the corresponding set thresholds. If the RSSI value of any signal receiving device is greater than the set threshold, the spatial triangulation positioning algorithm is started; A second calculation module is used to calculate the position coordinates of the signal transmitting device based on the position coordinates of the multiple signal receiving devices through spatial triangulation calculation; The second judgment module is used to judge whether the position coordinates of the signal transmitting device fall within the monitoring area according to the boundary coordinate values of the monitoring area preset in advance; The generation module generates an alarm message including the location and time information of the signal transmitter when confirming that the location coordinates of the signal transmitter fall into the monitoring area.

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