JPH0480353B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an emergency security system, and more particularly to a new security method that can detect an emergency signal sent by a victim in an emergency and specify the starting position and sender. [Prior Art] Alarm devices such as emergency alarm buzzers have been provided in the past as a precaution in case of encountering a danger that poses a threat to human life or body.
This device is carried at all times, and in the event of an emergency, it can be operated to emit an alarm sound to startle the perpetrator. This alarm sound can alert neighbors to the occurrence of an emergency and may serve as an opportunity to call the police or request rescue, but this purpose may not necessarily be achieved in areas where residences are not densely populated and traffic volume is low. There is. Furthermore, it cannot be denied that the perpetrator who hears the alarm may become agitated and commit further acts of violence, which could have the opposite effect. The frequency of kidnapping incidents has become a major social problem in recent years, but the nature of the kidnapping incident is usually only discovered when the perpetrator makes a threatening request by telephone or other means to the victim's home. The police learned of the incident through a report from the victim's family, etc., and began an investigation by installing a reverse detector on the phone, but the victim's family prioritized saving the victim's life. In many cases, reports to the police are not made or are delayed, making it difficult to expect prompt investigation and rescue. In order to solve these problems, the area is divided into multiple sections, antennas are installed in each section, the antennas are scanned and the radio wave intensity is stored for each antenna, and the intensity of the radio waves stored in the area is stored. 1987- Tokuko which identifies the location of the signal by comparing the signals with each other.
A portable transmitter that continues to transmit a specific signal by using the signal transmission location detection method described in No. 40555 or a switch operation, and a sharp unidirectional antenna that constantly rotates and sweeps in the direction of the transmitter. means for automatically transmitting the direction of arrival of the radio waves from the receiving station to a central station; There is a mobile communication system for emergency rescue described in Japanese Patent Application Laid-Open No. 51-69303, which has means for comprehensive management and automatically calculating the coordinates of the transmitting point of the transmitter. In addition, Japanese Patent Application Laid-Open No. 52-119092 discloses that, based on the same principle as the emergency rescue mobile communication system described in the above-mentioned Japanese Patent Application Laid-Open No. 51-69303, a unique modulated signal is transmitted while rotating a directional antenna. An emergency notification device has been proposed that receives radio waves with a certain frequency and monitors for distress in yachts, motorboats, etc. [Problems to be Solved by the Invention] However, the method for detecting the signal transmission location described in the above-mentioned Japanese Patent Publication No. 57-40555 has the disadvantage that the accuracy is extremely low because it is classified for each antenna. Furthermore, if the area is divided into small sections to improve accuracy, a large number of antennas will be required. Furthermore, in the emergency rescue mobile communication system described in JP-A No. 51-69303 and the emergency call device described in JP-A-52-119092, it is necessary to keep rotating the antenna even when there is no emergency communication. There is,
There were problems in that it consumed unnecessary power and further shortened the life of the equipment. Furthermore, when trying to identify the caller by including an individual identification signal in the emergency signal, in the emergency rescue mobile communication system and emergency communication device described in the above publication, until the directional antenna points in a specific direction, There were problems in that the signal could not be received in some cases, and it took time to identify the person who issued the emergency signal. As shown in the above-mentioned publication, when detecting the transmission location of an emergency signal using a rotating directional antenna, it is difficult to accurately detect the transmission location because radio wave conditions are poor in urban areas with complex buildings. There was a problem that there were cases where it could not be detected. The present invention was made in view of such circumstances,
The purpose of the present invention is to provide a security method through the transmission and reception of emergency signals, which enables quick rescue even in the case of kidnapping, terrorist incidents, etc., and which is also effective in preventing recurrence of these malicious incidents. [Means for Solving the Problems] A security method performed by transmitting and receiving an emergency signal according to the present invention in accordance with the above-mentioned object is a security method for a security target carrying a transmitter capable of transmitting an emergency signal using radio waves of a predetermined frequency. A security method in which security is performed by transmitting and receiving the emergency signal, wherein in an emergency, the emergency signal is transmitted from the transmitter by the operation of the security gymnast, and the emergency signal is transmitted from all positions within the security target area. The emergency signal is received by a plurality of omnidirectional antennas installed to receive the emergency signal, the general range of the transmission position of the emergency signal is determined thereby, and then two or more The directional antenna is rotated to detect the direction in which the electric field strength is maximum, and this is analyzed by a computer, and the principle of triangulation is applied to identify the transmission position of the emergency signal, and its position is is displayed together with a nearby map on a display connected to the computer, and furthermore, the emergency signal emitted from the transmitter includes an individual identification signal for identifying the person who sent the emergency signal, and the individual identification signal is By decoding the emergency signal, the person who sent the emergency signal can also be identified. [Operation] The subject of this emergency security system carries an emergency signal transmitter at all times, and when he or she senses danger to his or her body due to kidnapping or terrorism, he or she immediately operates the transmitter to send out an emergency signal. Radio waves of a predetermined frequency are allocated to this emergency security system by the radio wave management station in advance, and the transmitter emits an emergency signal of this predetermined frequency, and the frequency band is exclusive to this emergency security system. preferable. Further, this transmitter is required to have a necessary output to ensure reliable reception by an antenna, which will be described later. The ground system of this emergency security system is roughly divided into a monitoring subsystem, a tracking subsystem, and a computer subsystem. The monitoring subsystem is a receiving system with omnidirectional antennas, which are deployed in large numbers within the security target area and constantly monitor the presence or absence of emergency signals. A large number of receiving stations of the monitoring subsystem are deployed so that emergency signal transmissions can be detected from all positions in the area to be guarded, depending on the sensitivity of the omnidirectional antenna provided at each receiving station. may be received by multiple receiving stations. This monitoring subsystem can also be implemented using an existing security security system network. The tracking subsystem is a receiving system with directional high-sensitivity scanning antennas, and is installed at several key points within the security target area. This tracking subsystem is activated from the moment the monitoring subsystem detects an emergency signal, and rotates directional antennas, typically located at two separate locations, to detect the direction in which the directional antennas exhibit the strongest electric field strength;
After determining the two receiving directions, the emergency signal transmission position is determined by applying the principle of triangulation from the receiving direction and the receiving station number (the two points where the directional antenna that detected the receiving direction is located). Calculate and identify. The computer subsystem integrates information between the monitoring and tracking subsystems, supports these operations, and displays tracking information as well as a map of the area on its display to help prepare for rapid rescue. . Furthermore, the computer in this computer subsystem is used to accurately detect the receiving direction in which the directional antenna exhibits the maximum electric field strength in the tracking subsystem. The emergency signal transmitter carried by the person to be guarded is preferably equipped with a function to transmit an individual identification code, for example, by PCM (Pulse Code Modulation), so the computer subsystem can detect the location where the emergency signal is transmitted. At the same time as tracking and identifying the individual, the individual identification code is decoded. This makes it possible to identify not only the location of a person encountering danger, but also the person responsible for the danger, allowing rescue preparations to be made tailored to each person. As described above, the present invention provides an emergency security system that includes an emergency signal transmitter that each person to be guarded always carries, and a ground system that includes a monitoring subsystem, a tracking subsystem, and a computer subsystem. This is a method that can specify the signal transmission position. The outline of this emergency security system is shown in Figure 1. The determination of the location of the emergency signal by the tracking subsystem, preferably with the aid of a computer subsystem, is accomplished by applying triangulation principles. This identification method will be explained in detail below with reference to specific examples. In Figure 2, point A and point B are fixed points,
The half line passing through point A is La, and the half line passing through point B is Lb.
Let the angles these half-lines make with line segment AB be α and β, respectively. Also, let C be the intersection of La and Lb. Here, the angle α between the line segment AB and its both ends is
Once β is determined, only one triangle ABC is determined.
The position of C is thus specified. This is the principle of triangulation. Therefore, the receiving stations in the tracking subsystem are placed at points A and B, and the omnidirectional antennas at these receiving stations are rotated so that the direction of maximum electric field strength (i.e., the direction in which the emergency signal is received) is a half-straight line. La,
If it is detected that the direction is Lb, the source C of the emergency signal is identified to only one point. Hereinafter, as shown in FIGS. 3A to 3C, the position of point C will be examined on the XY plane, with point A as the origin and point B on the X-axis. The angle between sides AB and AC is α,
Let β be the angle formed by side BA and side BC. Points A, B,
Let the coordinates of C be (0, 0), (b, 0), (x,
y), the coordinates (x, y) of point C in FIG. 3A can be found as follows. y=x tanα...(1) y=(b-x)tanβ (2) From equations (1) and (2), x tanα=(b-x)tanβ ∴x(tanα+tanβ)=b tanβ ∴x=b tanβ/(tanα+tanβ)...(3) From equations (1) and (3), y=(btanα・tanβ)/(tanα+tanβ)...(4) From equations (3) and (4) above, the coordinates of point C ( x, y) are specified. Note that the above calculations were made for the case of Fig. 3 A, that is, 0° < α < 90°, 0° < β < 90°, but similarly for the case of Fig. 3 B, that is, 90° < α < 180°. ,
This also holds true in the case of 0°<β<90° and in the case of FIG. 3C, that is, in the case of 0°<α<90°<β<180°. Furthermore, even if point C is below line segment AB, that is, below the X axis, the coordinates of point C can be found in the same way using equations (3) and (4). A formula for determining the coordinates of point C in a more special case is shown below. When α=90°, 0°<β<90° x=0, y=b tanβ When 0°<α<90°, β=90° x=b, y=b tanα Furthermore, the following special In this case, it is not possible to determine the coordinates of point C, but its range of existence can be determined as follows, and by further tracking, the position of point C can be easily discovered. When α=0° and β=0° Point C is between points A and B on the X-axis. When α=0° and β=180° Point C is on the right side of point B on the X-axis. When α=180° and β=0° Point C is on the left side of point A on the X-axis. [Test Example] In order to confirm the effectiveness of the calling position identification method according to the present invention, a test was conducted in the following manner. As a portable emergency signal transmitter, use a commercially available radio control transmitter for models (manufactured by Futaba Corporation, product number FP-8AP, 40MHz band), and keep this switch on at all times while transmitting radio waves. The person was moved. The receiving device is a 4-element directional Yagi antenna (manufactured by Maspro Electric Works, product number
50T4, 52MHz) 4m on the roof of a 4-story building
Antenna rotation device with control device (manufactured by KENPRO, product number KR-
5600A), and the direction showing the maximum electric field strength was visually detected by connecting an electric field strength meter (manufactured by Leader Electronics Co., Ltd., product number LFC-945) with a coaxial cable (75Ω). The purpose of this test is to collect data that shows the relationship between time and the transmitting position at that time (hereinafter referred to as transmitter data), and data that shows the relationship between time and the direction of the antenna that shows the maximum electric field strength at that time (hereinafter referred to as transmitter data). (hereinafter referred to as antenna data) are recorded separately.
After the experiment, these transmitter data and antenna data are compared to confirm whether the transmitting position of the radio wave and the receiving direction of the antenna match. A map of the location where this test was conducted is shown in Figure 4.
The antenna was installed on the roof of building number 14 (marked with an x).
Those carrying transmitters started from the same building, number 14, and circled the course clockwise along the thick line.
The moving speed was as fast as a leisurely walk, and the parts marked with ○ in the diagram were stopped for 5 to 10 minutes. We also stopped at the roof of building number 16 on the way. All transmitter positions along this route, that is, the transmission sources, can be seen directly from the antenna installed on the roof of Building 14. As shown in Figure 4, the X-axis runs from west to east and the Y-axis runs from north to south, and the transmitter position is expressed by its (x, y) coordinates. The installation position of the antenna on the roof of Building 14 is (157, 61), and its direction is facing west.
It was set to 0° (360°). Tables 1 and 2 show the antenna data and transmitter data obtained as a result of testing as described above.

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〔Effect of the invention〕

According to the security method performed by transmitting and receiving emergency signals according to the present invention, emergency signals from all positions within the security target area are received by a plurality of directional antennas. This allows you to confirm that an emergency signal has been issued and its approximate range. Therefore, it is possible to quickly know that an emergency signal has been issued, and since the emergency signal includes an individual identification code, it is possible to detect this and identify the person to be protected. Next, after confirming that the emergency signal was activated,
Since two or more directional antennas are rotated to search for their transmission positions, there is no need to constantly rotate the directional antennas, and there is no need for wasted power consumption. Furthermore, the life of the equipment will also be extended. Then, the directional antenna is rotated to detect the direction in which the electric field strength is maximum, and this is analyzed by a computer using the principle of triangulation to specify the transmission position of the emergency signal, Since the information is displayed on the display along with a map of the surrounding area, the location of the emergency signal can be accurately detected and rescue operations can be carried out promptly. In this case, even if an emergency signal is issued in a city with many buildings and other obstacles in the surrounding area, and it is difficult to determine the exact location by position measurement using the rotational search using the directional antenna, multiple directions are set up in advance. Since the general position of the emergency signal can be confirmed using the directional antenna, there is an advantage that the position can be measured more reliably. Furthermore, since the emergency signal transmitter of the present invention is carried by the person to be guarded at all times and transmits the emergency signal by himself/herself when he or she senses danger, there is no need for family members to report the situation. The security system can be activated extremely quickly and is expected to be particularly effective against kidnapping and terrorist incidents, and is also expected to be effective in preventing the recurrence of these malicious incidents.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of the method of the present invention;
Fig. 2 is an explanatory diagram showing the principle of the triangulation method applied in the method of the present invention, A to C in Figs. 3 are explanatory diagrams to show the principle of the triangulation method in more detail and concretely, and Fig. 4 The figure is a schematic map showing the location of the receiving antenna and the moving route of the transmitter used in the test example.

Claims (1)

[Scope of Claims] 1. A security method for guarding a person to be guarded who carries a transmitter capable of emitting an emergency signal using radio waves of a predetermined frequency, by transmitting and receiving the emergency signal, the method comprising: is transmitted from the transmitter by the operation of the person to be guarded, and the emergency signal is transmitted by a plurality of omnidirectional antennas installed so that the emergency signal can be received from all positions within the region to be guarded. The general range of the transmission position of the emergency signal is determined based on this, and the two or more directional antennas are then rotated to detect the direction in which the electric field strength is maximum, and this is transmitted to the computer. The transmitting position of the emergency signal is determined by analyzing the signal by applying the principle of triangulation method, and the position is displayed on a display connected to the computer along with a nearby map; The emergency signal to be emitted includes an individual identification signal for identifying the person who sent the emergency signal, and the person who sent the emergency signal is also identified by decoding the individual identification signal. A security method carried out through the transmission and reception of emergency signals.