JPH069998B2 - Boarding person monitoring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an occupant monitoring device for issuing an alarm when an occupant of a ship falls into the water or the sea.

(Prior Art and Its Problems) Conventionally, there has been proposed a rescue signal transmitting device which detects a passenger of a ship who has fallen into the sea and automatically performs a procedure for rescue. . For example, as disclosed in Japanese Patent Laid-Open No. 60-103735, when a passenger carrying a slave unit as a transmitter falls into the sea, the radio wave from the slave unit is cut off and the reception is installed on the ship. Since the receiving input of the aircraft decreases, a monitoring device is used that detects this and issues an alarm signal.The alarm signal of this will stop the engine of the ship and the transceiver will notify the occurrence of an emergency situation. It is designed to transmit a signal. In order for appropriate rescue activities and safety to be protected by such devices, the rescue signal should be issued only when the occupant actually falls, and should not be issued otherwise. It is necessary to increase the reliability of the monitoring device so that the engine will not be stopped.
However, in the conventional device, since the radio wave of the slave unit is received by one antenna, a dead point occurs due to the directivity of the slave unit and the interference of nearby obstacles. For this reason, depending on the position and attitude of the passenger carrying the child device, the receiving input of the receiver may be reduced and a warning signal may be issued, which may cause the engine to stop and issue a rescue signal in a non-emergency situation. There was a problem.

(Technical Means for Solving Problems) In view of the above-mentioned problems, the present invention prevents reception input from decreasing as much as possible even if the position or attitude of a passenger carrying a slave device as a transmitter changes. The purpose is to prevent as much as possible the malfunction that the warning signal is issued even if the passenger is not falling, and the technical means for that is to carry it by the passenger and emit radio waves intermittently. It has a machine 1 and antennas 2a, 2b and a receiver 4 installed on the ship, and the receiver 4 emits an alarm signal when the reception input from the transmitter 1 falls below a certain level. A plurality of the antennas 2a and 2b are installed, and the plurality of antennas 2a and 2b are alternately arranged in a time sufficiently shorter than the duration of the radio wave emitted by the transmitter 1. Switch to and disconnect from the receiver 4 The replacement device 3 is provided.

(Example) Hereinafter, the Example of this invention is described based on drawing.

In FIG. 1, the handset 1 as a transmitter is, for example, 130 MHz
A carrier wave of a certain degree is amplitude-modulated by a modulation pulse as shown in FIG. 4a, and as shown in FIG. 4b, radio waves are intermittently emitted at a constant cycle. In the figure a, for example, t ₁ = 100 msec and t ₂ = 300 msec. The two antennas 2a and 2b are located at different positions so that even if the position or attitude of the passenger carrying the cordless handset 1 is changed, either antenna 2a or 2b can receive radio waves at a certain level. is set up. These are usually installed at intervals of 2 m or more, and for example, in the case of a small boat, they are installed in a place with good visibility, such as on the front and rear bridges. The switching device 3 is for alternately switching the outputs of both antennas 2a and 2b to connect to the receiver 4, and includes a switch unit 5, a switch driving unit 6, and an oscillating unit 7. As shown in FIG. 4c, the oscillating unit 7 has a duty ratio with a period sufficiently shorter than the duration (width of the modulation pulse) t _{1 of the} radio wave emitted by the slave unit 1, for example, t ₃ = 10 msec. It oscillates a switching pulse of 50%, which activates the switch driving section 6 to drive the switch section 5. FIG. 2 shows a more specific example of the switching device 3, the switch unit 5 is constituted by diodes D _1, D _2, alternately diodes D _1, D ₂ by the switch driving section 6 including the transistor TR1 A positive potential is applied to. In the figure, a high frequency preamplifier 8 is provided.

The output from the switching device 3 is sent by the cable 9 to the receiver 10 of the receiver 4 where it is demodulated. When both antennas 2a and 2b are receiving radio waves of sufficient intensity from the handset 1, the output from the receiving unit 10 is a pulse waveform for modulation in the handset 1 as shown in FIG. A waveform similar to (a) in the figure is obtained, but if not, for example, both antennas 2
When there is no reception input of either a or 2b, a waveform which is the AND of the pulse waveform of FIG. 7A and the switching pulse waveform of FIG. The integrator 11 integrates the output of the receiving unit 10 to smooth the switching pulse component, so that the waveform of FIG. 4e becomes a waveform as shown in FIG. The waveform shaping section 12 is composed of, for example, a Schmitt trigger element, and when the input of FIG.
The waveform of is output. FIG. 3 shows a more specific example of the receiver 4, in which the switching circuit SWG is a detector D.
The level of the carrier wave received from the ET is detected, and a high level logic signal is output when the level is higher than a certain value.

The detection unit 13 receives the output signal of the receiver 4 and outputs an alarm signal indicating that the radio wave from the cordless handset 1 is cut off. The pulse time width of the pulse signal output from the waveform shaping unit 12 And the period are measured, and this is compared with the time width t ₁ and the period t ₂ of the modulation pulse of the slave unit 1 to detect whether or not it is within a certain allowable range. For example, let the signal pass through three pulse period confirmation means with pulse periods of 240 msec or less, 360 msec or less, and 5 sec or less, and if the signal deviates from 300 msec ± 20%, the interference indicator lamp will blink and the signal will be interrupted for 5 seconds Output a signal. Such a detection unit 13 can be realized by a program using a microcomputer.

The alarm unit 14, when an alarm signal is output from the detection unit 13, emits an alarm sound by, for example, a buzzer or audio broadcasting,
The engine of the ship is stopped after a lapse of a certain time, and after a lapse of a certain time, a rescue signal is transmitted by a wireless transmitter to inform the occurrence of an emergency.

According to the above-described embodiment, since the two antennas 2a and 2b are installed at different positions to receive the radio wave emitted from the child device 1, the position and attitude of the passenger carrying the child device 1 Even if the frequency changes, either of the antennas 2a, 2b can receive radio waves at a certain level or higher, and the antennas 2a, 2b
Since 2b is switched alternately and connected to the receiver 4, the receiver 4
Can obtain a constant reception input regardless of the position of the child device 1 on the ship. Since the switching time by the switching device 3 is sufficiently shorter than the connection time of the radio wave emitted from the slave unit 1, even if only one of the two antennas 2a and 2b has a reception input, the integrator 11 or the like is used. The signal waveform can be easily restored, and the presence or absence of radio waves from the handset 1 can be easily and reliably detected. Therefore, when an occupant carrying the cordless handset 1 falls into the sea and the radio wave is interrupted, an alarm signal is surely issued, and the occupant does not fall and is on the ship, but the position and the attitude may change. It is possible to prevent the malfunction that an alarm signal is emitted,
The reliability of the device can be improved. Since the handset 1 emits radio waves intermittently, it consumes less power and has a longer battery life, and it is possible to identify a plurality of handset by varying the duration and the cycle. .

Although the two antennas 2a and 2b are provided in the above-described embodiment, the number of antennas may be three or four or more, and these antennas may be sequentially connected to the receiver one by one, or two antennas may be paired. Alternatively, each group may be switched and connected. The time width t ₁ and the cycle t ₂ of the modulation pulse of the slave unit 1, the cycle t _{3 of the} switching pulse, and the like can be appropriately determined. The radio wave of the handset 1 may be modulated at a low frequency. Various circuits such as the switching device 3 and the receiver 4 can be adopted. INDUSTRIAL APPLICABILITY The present invention can be used for monitoring workers in ships, offshore plants, and other hazardous work areas.

(Effects of the Invention) According to the present invention, it is possible to prevent the received input from dropping below a certain level depending on the position and attitude of the passenger who carries the slave device that is the transmitter, and the passenger does not fall. However, it is possible to prevent a malfunction that an alarm signal is issued. Therefore, the reliability of the entire device is improved, which allows expectation for a quicker rescue operation and protects the safety of the passenger. Since the switching time by the switching device is sufficiently shorter than the connection time of the radio wave emitted by the slave unit, the signal waveform can be easily restored by using an integrator etc. even when only one of the two antennas has a reception input. Therefore, it is possible to easily and surely detect the presence or absence of the radio wave from the slave unit. Also, since the transmitter emits radio waves intermittently, the battery life is extended and the continuous use time of the transmitter is extended accordingly, and there is less risk of unexpected emission of radio waves during use, reducing reliability. improves.

[Brief description of drawings]

1 shows an embodiment of the present invention in the drawings, FIG. 1 is an overall block diagram, FIG. 2 is a circuit diagram showing an example of a switching device in detail, and FIG. 3 is a circuit diagram showing an example of a receiver in detail. , FIG. 4 is a diagram showing the signal waveform of each part. 1 ... Slave unit (transmitter), 2a, 2b ... antenna, 3 ... switching device, 4 ... receiver.

Claims (1)

[Claims] 1. A transmitter, which is carried by a passenger and intermittently emits radio waves, and an antenna and a receiver installed on the ship,
The receiver is an occupant monitoring device for issuing an alarm signal when the received input from the transmitter falls below a certain level, and the plurality of antennas are installed and the plurality of antennas are installed. 2. A monitoring device for passengers, characterized in that a switching device for alternately switching the antenna of (1) for a time period sufficiently shorter than the duration of the radio wave emitted by the transmitter and connecting it to the receiver is provided.