JPH0820500B2 - Radio or airborne ultrasound system for swimming safety management - Google Patents

Description

The present invention relates to a radio wave or airborne ultrasonic system for safety management of swimmers in swimming pools, seas, lakes, rivers and the like, and more specifically, it remains submerged under water. The present invention relates to the system for detecting and identifying the occurrence of a swimmer who does not appear, or for detecting the final position immediately before stopping the disappearance of the swimmer.

Conventionally, for safety management of swimming, only a method such as keeping an eye on from the surface of the water by the observer or regularly making a roll call is performed. Many accidents show that these methods are sometimes uncertain. That is, in many cases, the only result is that, if you notice it, you will sink to the bottom of the water and die. If the person who encounters a difficult situation is submerged in water while announcing the fact that he is "drowning", it will immediately start rescue operations, so there are still some cases in which he cannot help. However, at least such an example is not intended to be the main purpose or object of the present invention. That is, the purpose of the device according to the present invention is to automatically discover a victim who has been unknowingly or lazily immersed in water without being known by anyone.

As an electronic system for automatically detecting a water victim, there is a previous invention of the same inventor, Japanese Patent Application No. 60-216037, and the like. However, in this prior invention, since the system is essentially an underwater ultrasonic system, it is not possible to obtain a basis for issuing an alarm if the victim is simply submerged in water.
Only after staying in one place for more than a few minutes, the alarm will be activated. The difficulty of this system's alarm generation method is that the alarm is generated only before it is too late. In addition, some pools or swimming facilities have a certain effect in recent years by intentionally generating waves or unidirectional flow.However, in these, search for a submerged transmission source. The scheme does not serve that purpose.

Further, a device for detecting the feeling of the transmitted signal due to the submersion of the transmitter carried by the swimmer in an antenna or a wave receiver arranged in the water is disclosed in, for example, JP-A-62-36585 and JP-A-62-2.
52219 and also in US Pat. No. 3,810,146 and the like. However, in these examples, it is difficult to identify the position of the transmission source unless an antenna or receiver is placed everywhere in the water of the monitored space, and it is not fail-safe, that is, the transmitter fails and the signal is If there is a break, the transmitter has the essential drawback that it is not present in the water and is mistakenly interpreted as a safe side. Therefore, it is easy to overlook an accident and lack practicality.

Therefore, the main purpose of the present invention is to detect a person who is in the water at that time, put it on the preliminary registration list for alarm generation, and actually give an alarm if it does not recover after a certain period of time, and submerge it. It is to realize an electronic system (especially a radio wave system or an aerial ultrasonic system) that announces the position of a point. Here, the term "fixed time" can be set to be much more familiar than the case of the underwater ultrasonic system for the same purpose according to the invention of the same inventor, for example, about 1 to 2 minutes. A person who can hold his breath in the water for such a long time does not know that it is a trained person, and it is almost impossible for a general swimmer as the subject of the present invention. Loss of signal feeling can be a reliable basis for alarm occurrence. Since the radio wave system of the present invention monitors the space above the water surface, the sensitive area must be finite. Therefore, a signal source submerged in water will also come out of the water and fall outside the sensitive area. A signal source that has walked away to is similarly pre-registered as a signal source with a discomfort. However, the two can be discriminated from each other depending on whether the position on the verge of the signal entry is on the water surface or outside the water surface.

That is, the alarm should be generated only when the position of the transmission source at the time when the signal is heard is on the spatial region of interest, that is, on the surface of the monitored swimming pool. Sources that stumble outside, that is, leave the pool and leave the monitored space, are not to be alarmed.

The present invention typically attaches an antenna to the swimmer's neck somewhere above (eg, the head) by means of a strap or belt-like attachment means, and the antenna has an identification load such that it can be individually identified. Is mounted with a transmitter for giving a modulated transmission signal, and at the center, an antenna for always receiving the transmission signal, a receiver, and information on the transmission position of the transmission signal are constantly acquired. Means, a means for detecting a disruption of the transmitted signal, the disruption occurring in a spatial region of interest (ie a monitored swimming pool),
Further, when the signal does not return even after the lapse of the scheduled time, it is implemented by a structure having a means for generating an alarm.

Such a structure for generating an alarm when a signal is interrupted is disclosed in the above-mentioned JP-A-62-36585, JP-A-62-252219, and U.S. Pat. The configuration is essentially fail-safe as compared with the configuration in which an alarm is issued, and has an advantage that an accident that an alarm is not generated by mistake when an alarm is necessary can be prevented.

However, in a further preferred embodiment of the present invention, in addition to the transmitter on the swimmer side, the center side has an array antenna for constantly receiving the transmitted signal, an array receiver, and a hologram analysis means. Means for detecting the interruption of the transmission signal, and means for estimating the position of the transmission source of the transmission signal immediately before the interruption by analyzing while holding the hologram on the array formed by the signal received by the array antenna immediately before the interruption And having means for issuing an alarm when the signal does not return even after the lapse of a scheduled time, and also displays the estimated position of the transmission source of the transmission signal immediately before the interruption when the alarm occurs. A radio wave system for swimming and safety, comprising: Here, the feature of the point that the array antenna is used to observe the hologram on the array formed by the received signal is that the array antenna is first placed in the air in the vicinity of the monitored space as a unit. In that case, it does not have to be troublesome in that it is distributed in water as described in JP-A-62-252219 or otherwise distributed even in the air.

On the other hand, however, the present invention has the feature that it can be used by translating airborne ultrasonic waves from radio waves almost as described later.

The principle of operation of the device according to the present invention will be described below with reference to the drawings, and then preferred embodiments will be introduced. (First, the case of using radio waves will be explained.) FIG. 1 is for explaining the principle of the present invention, in which each swimmer (1a), (1b), (1c) ... ), (2b), (2c), etc., and always wear this on the part of the body surface that is almost always in the air.
A typical example is to put it around the head in a staggered pattern. The transmitter itself has a small antenna and also has an oscillating circuit which is energized by a battery power source, and always emits weak radio waves as scheduled. However, when it is submerged in water, radio waves can no longer be effectively emitted in the air due to the conductivity or high dielectric constant of water. Therefore, the reception system (3) uses its array antenna (4) to receive and monitor the radio waves emitted from these signal sources from the upper side or the obliquely upper side, or from the horizontal direction at the poolside or slightly away. , When the signal extinction of a certain signal source is found, the position at the time of the signal extinction is obtained from the received data immediately before that, and the time is set to the scheduled time.
For example, if the radio wave is not sensed again after waiting for 1 minute, an alarm is issued and the position of the dead point is displayed. In performing such work, reception data is created by the array antenna (4) and the receiver (5), and a hologram formed by a reception signal on the array antenna is obtained.
Therefore, the monitoring is carried out by the personal computer (6) which introduces the hologram data using the receiver as an input data generation source and solves the hologram data to identify the position of the transmission source. The position information is displayed on the screen of the CRT display device of the personal computer together with other additional information. The alarm is given using the beeper of the personal computer. These video and audio will allow the observer or rescuer to initiate appropriate activities.

The above is a schematic description of the system principle of the present invention. A typical example will be described below.

FIG. 2 shows an example of the transmitter that can be carried by each swimmer described above, in which the oscillator (21) is formed on an elongated flexible substrate (22), and the oscillator (21) is formed substantially at the center thereof. A circuit section (24) that is watertightly sealed by a sealing material (23) and conductors (25) that extend to both sides of the circuit section and serve as antennas.
It is made by. The operating power of the circuit is also watertight, and the battery (26) is mounted on the flexible substrate (22).
Will be covered by. A power switch is not provided in particular, and when the battery (26) is attached, the electric wave is transmitted by itself. That is, the battery (26) is, for example, a coin-shaped lithium primary battery, which is fitted into the holder (27) on the substrate (22) and is watertightly fitted when the lid (28) is fitted. (29) is a stretchable string or belt like a rubber band, with which the oscillator can be fitted like a hammer on the swimmer's head.

Since the radio wave emitted from this oscillator is sufficiently weak, there is no harm even if it is mounted so close to the human body. On the contrary, the radiation efficiency of the radio wave is a little lower than that when it is left in the air, but the efficiency is not so bad as to be practical. However, as shown in this example, the antenna is a dipole antenna or the like, and its overall length is slightly smaller than half a wavelength, and its input impedance is high, in other words, it is close to a field emission or voltage drive type. , Which is advantageous in the practice of the present invention. After all, if that person is submerged in water and loaded with water,
That is, when shunted by the low RF impedance caused by the high dielectric constant of water, the radiation ability is more effectively destroyed.

The transmission frequency of the transmitter is UHF band (0.3 to 3 GHz), especially 0.5
A region of about 1.5 GHz is preferable. This is due to two reasons. One is holography with an appropriate resolution (for example, 0.5 to 1 m) in an area to be monitored (for example, a radius or a direct viewing distance of about 50 to 70 m) with a wavelength of this level. This is because it is suitable to be covered (ie, it enters the Fresnel zone of the array antenna as described later). If it is longer than this, the resolution of the position identification will be hindered, and if it is too short, holograms will be sampled and processed. This is not preferable because it requires a large amount of hardware.

Another reason why this frequency range is preferable is that a very simple low power oscillation circuit with necessary and sufficient frequency accuracy can be used with good reproducibility and mass productivity by using a SAW (acoustic surface wave) resonator (or filter). Because it can be realized.

In order to be able to individually identify the source, some sort of labeling method is used to individually provide ID information. The labeling can be based on the transmission waveform of the transmission source or the modulation waveform of the envelope, but can also be based on the transmission frequency itself, or both can be used together. As an example, in the former case, the transmission source periodically emits a pulse or burst carrier and performs some modulation within its duration, for example, amplitude modulation or phase modulation by a binary code signal. At the receiving side, it is necessary to demodulate the pulsed signal at the same time as it is received and identify the source. In addition, since multiple sources coexist in the same monitored area, the pulses of each source do not overlap in time even if each independently transmits, or the probability of overlapping is small enough, Must have a very sharp duty ratio. For example, in order for the probability that pulses emitted from 20 to 30 sources with random phases to collide in air are sufficiently small (for example, ≤0.1), the duty ratio of each must be 10 ^-5 to 10 ^-6 or less. I won't. For example, when the pulse period is 1 second to several seconds, the burst duration is several μS to several tens μS. However, in the UHF band, a burst having such a length can sufficiently transmit binary serial data of 10 to 10 bits. Further, in this method, the operating frequency of the system can be unified to one, and the SAW element of the oscillator can be unified to one kind, which is preferable from the viewpoint of mass productivity of the element. However, since the internal circuit of the oscillator includes the individual code signal generating means and the modulating means, it has to be slightly complicated.

On the other hand, the method of identifying the source only by the carrier frequency can simplify the oscillator circuit itself because the oscillation waveform can be unmodulated CW, but the SAW element of the frequency deciding element is different. Must be used.

Regardless of which method is used for labeling, a transmitter having an outline as shown in FIG. 2 can be used.

FIG. 3 shows a receiving system including an array antenna for capturing an electromagnetic wave emitted from each source at a place coming from a monitored space including a large number of sources as shown in FIG. It shows an outline. That is, in this case, as an example, the array antenna (31) is a one-dimensional array with the dipole antenna or the loop antenna having poor polarization plane selectivity as the individual elements (32) and the coaxial cable serving as the feed line of each element is Wire bundle (3
It is introduced into the receiver (34) while performing 3). Receiver (3
In 4), the number of elements (in this case, 1 as an example)
Unit receivers (35) with only 6) receiving channels are prepared, and these are super heterodyne type as well-known general-purpose, but at the same time as the receiver array, holograms given by the wavefront entering from the monitored space are simultaneously provided. For the sake of convenience of collecting all at once, one station (36) is commonly used by passing one through. Here, the width W of the array is determined so as to have a sufficient width to incorporate the array into the Fresnel zone so that the source position can be identified on almost the entire surface of the monitored space in a two-dimensional manner. . Between the width W of the array and the wavelength λ of the used radio wave, The range of the distance d with such a relationship can be called the Fresnel zone, so if you try to cover a space of 50 × 70 m, for example, if you use 1 GHz (wavelength about 30 cm), you need several meters as W. Becomes Thus, according to the well-known principle of wavefront entry and detection, the outputs of these receivers (35) as a whole give a one-dimensional complex hologram formed by the wavefront sensed by the array antenna (31). The hologram is introduced into a personal computer (38) through an interface device (37) including an A / D converter so that it can be inspected each time a pulse from a transmission source is detected. At the same time, one or a plurality of outputs of the receiver are used to detect the pulse sensation. This may be simply used by binarizing the detection output (video output) of the receiver by a process such as threshold comparison, and the effective component to be analyzed from the result of data collection via the above interface device. You may judge based on whether it can be discovered.

If the hologram is inspected, that is, the one-dimensional hologram thus obtained is temporarily held and subjected to backprojection calculation to constantly estimate the position of the signal source, that is, the distance and azimuth from the array antenna, Information about the position of the signal source can always be obtained prior to the occurrence of the interruption.
This calculation is performed by software on the personal computer (38). Since the number of antenna elements is not so large, this backprojection operation can be executed at a sufficiently practical speed even with software using a general-purpose compiler language of a personal computer for business use. However, interpreted languages are generally too slow to be useful for this purpose. The backprojection operation takes the form of a one-dimensional Fresnel inverse transform here, but as is well known, the Fresnel transform (both forward and reverse)
Since it is obtained with a slight modification than the Fourier transform, the software can easily reach the goal by modifying the program for the FFT or adding necessary additions before and after.

That is, when the primary source hologram is subjected to Fourier transform as it is, the parallel plane wave incident on the array antenna is analyzed, and the result is that the incident wave arriving from the infinity point with only the azimuth angle information has an intensity distribution in the azimuth space. It will be a remarkable analysis. Here, the Fourier transform and the inverse Fourier transform are essentially the same processing as mathematical or information processing procedures in a computer, except that the coefficients are different at most.
In order to perform the Fresnel transform by performing the Fourier transform, it is known that a technique of applying a quadratic function-like phase distribution to the data to be transformed, that is, the one-dimensional hologram and then applying the Fourier transform is well known. This is equivalent to adding a lens according to the curvature of the quadratic function.

That is, various curvatures of the additional phase distribution corresponding to the focal length of this lens are prepared so as to appropriately cover the observed space, and the one-dimensional hologram is corrected by each of them, and Fourier transform (specifically, FFT program) is performed. Batch processing). As a result, each focal length is a distance axis,
The amplitude data of the conversion result obtained by calibrating the arrangement of the bins of the FFT output in each azimuth angle or the axis that is substantially orthogonal to the distance axis means the distribution status of the source in the observed space. Therefore, it is only necessary to recognize and identify the bin whose value is significant as the location of the source.

I mentioned earlier that the width W of the array must be large enough to capture the monitored space into the Fresnel zone in relation to the wavelength of the radio wave used. It is completely controversial with the requirement that a practically meaningful spatial resolution must be achieved in space.

Here, a method of entrusting the above Fresnel transform to the Fourier transform, that is, a technique of imposing a quadratic function-like phase distribution on the data to be transformed, that is, the one-dimensional hologram and then applying the Fourier transform is a preferable example. However, the present invention is not limited to this. Such signal processing for "solving a hologram" is a matter of common sense that can be easily implemented by a person skilled in the art, an experienced person or an expert.

Thus, the position of the source is identified in this way each time the pulse from the source is detected, but if the time required for this process is less than several hundreds of microseconds, it becomes an open path in the operation of the system. There is no such thing. This is a value that is significantly longer than the pulse width (several μsec to tens of μsec) of the individual sources mentioned above, but this is because the hologram data of each pulse is stored in the queue and the This is because it can be easily processed. At the same time as the hologram is unraveled to identify the location of the source, the source ID information can be decrypted by using at least one of the outputs of the receiver, or by properly combining the outputs. , Is temporarily stored in the personal computer along with location information. This work is also performed by demodulating the modulated waveform of the pulse of the transmission source through the interface device and then inspecting it by software.

Thus, the occurrence time, the position of the transmission source, and the ID code are sequentially registered in the temporary memory (stack) in the personal computer each time the pulse is sensed. It is possible without difficulty to keep dozens or hundreds of such data sets dating back in the past while constantly updating them. The data set in this stack can be converted into
Always inspect every few seconds. The contents of the inspection are "regarding the existence and feeling", which is prepared from the viewpoint that there is no source of sudden periodic feeling of feeling or a separate preparation.
It is either or both from the viewpoint that there is nothing missing from the list of sources. When a source with a weak or missing feeling is found and identified, an alarm is issued according to a scheduled procedure. As an example of the alarm generation procedure, first, whether or not the determination of the interruption or omission is credible is waited for, for example, 10 to 20 seconds, or an alarm generation request that is reported every moment during that period is integrated, and a certain number of times or more. When it comes to, it will be judged based on whether or not an alarm is really issued. Furthermore, it would be useful if the "emerging" signal source could also be used to generate another alarm according to a certain evaluation standard. Then, the alarm is on the PC (6).
While blinking on the CRT display, it is displayed with the last entry position and time of the corresponding signal source, its ID code or some identification information. It is also preferable to use a sound output means, a buzzer, a beeper, etc. together as an alarm means.

As is clear from the above, according to the present invention, a signal source that does not recover after being submerged in water, that is, a swimmer corresponding to the signal source can be found at an early stage, which is useful for preventing accidents. However, as is obvious to experienced people and experts,
The wave energy that can be used for the implementation and realization of the purpose of the present invention is not limited to radio waves, and almost the same signal handling can be realized by using ultrasonic waves in the air. 20KH as the frequency of ultrasonic waves that can be used
Around z to 50 KHz is good. In the case of ultrasonic waves, if the “antenna” described above is replaced with a “transducer” or an electroacoustic transducer, and if appropriate time and / or conversion or expansion / reduction on the frequency axis is performed, a system of the same idea can be obtained. Can be realized. Such a case can also be included as an embodiment of the present invention. However, since aerial ultrasonic waves have a one-way injection or emission propagation loss of 30 dB or more, one way below the surface of the water, the same as electromagnetic waves near 1 GHz (or more at extremely shallow depths) A distinction can be made. Also, dozens more than antennas near 1 GHz
Aerial ultrasonic transducers per KHz also have the advantage of being much smaller in size.

As described above, the present invention has a favorite to use a radio wave as a signal means to be used, but does not impede compensatory implementation by aerial ultrasonic waves.

[Brief description of drawings]

FIG. 1 shows the principle of the present invention, FIG. 2 shows an example of a portable transmitter, and FIG. 3 is a block diagram showing an outline of a receiving system.

Claims (6)

[Claims] 1. An antenna having a strap or belt-shaped mounting means for mounting it on the swimmer's neck somewhere above the neck (for example, the head), and being mounted on the antenna.
The center has a transmitter for giving a transmission signal whose identification code is modulated so as to be individually identifiable, and in the center, therefore, an antenna for constantly receiving the transmission signal, a receiver, and the transmission signal. Means for constantly obtaining information regarding the transmission position of the transmission signal, means for detecting a disruption of the transmission signal, and the disruption occurring in a spatial region of interest, and the signal does not recover even after a lapse of a scheduled time. The radio wave system for swimming safety management is characterized in that it has means for issuing an alarm. 2. An antenna having a string or belt-shaped mounting means for mounting the swimmer somewhere above the neck (for example, the head), and being mounted on the antenna.
It has an oscillator for giving an emission signal whose identification code is modulated so as to be individually identifiable, and thus an array antenna for constantly receiving the emission signal at the center, an array receiver, and a hologram. And a means for detecting the interruption of the transmitted signal, and a transmission immediately before the interruption by temporarily holding and analyzing the hologram on the array formed by the signal received by the array antenna immediately before the interruption. And means for estimating the position of the source of the signal, and means for issuing an alarm if the signal does not recover even after the lapse of a scheduled time, and immediately before the interruption with the occurrence of the alarm. The radio wave system for safety management of swimming according to claim 1, further comprising: a display unit that displays the estimated position of the transmission source of the transmission signal of the above. 3. The invention according to claim 2, wherein the array antenna has an opening size so as to accommodate the monitored area in the Fresnel zone in consideration of the wavelength of the radio wave used by the array antenna. Radio system. 4. An aerial ultrasonic wave transmitter having a string-like or belt-like attaching means to be attached somewhere above the neck of each swimmer (for example, the head), and the air attached to the ultrasonic transmitter. An ultrasonic wave transmitter, which has a transmitter for giving a transmission signal whose identification code is modulated so as to be individually identifiable, and a receiver for constantly receiving the transmission signal at the center , A receiver, a means for constantly obtaining information on the transmission position of the transmission signal, a means for detecting a disruption of the transmission signal, the disruption occurring in a spatial region of interest, and the scheduled time has elapsed. Even if the signal does not recover, it comprises a means for issuing an alarm,
Aerial ultrasound system for swimming safety management. 5. An aerial ultrasonic wave transmitter having a string or belt-shaped mounting means for mounting the swimmer somewhere above the neck (for example, the head), and the aerial ultrasonic wave transmitter. An array receiver which is mounted on a vessel and has an oscillator for giving an emission signal whose identification code is modulated so as to be individually identifiable, and for receiving the emission signal at a center at all times And an array receiver and a hologram analysis means, and means for detecting the interruption of the transmitted signal, and temporarily holding the hologram on the array formed by the signal received by the array receiver immediately before the interruption. While having the means to estimate the position of the transmission source of the transmission signal immediately before the interruption by analyzing
And a display means for displaying an estimated position of the transmission source of the transmission signal immediately before the interruption when the alarm is generated when the signal does not return even after a lapse of a scheduled time. Characterized by comprising,
An aerial ultrasonic system for safety management of swimming according to claim 4. 6. The array receiver according to claim 1, having an opening size so as to accommodate a monitored region in its Fresnel zone in consideration of a wavelength of an ultrasonic wave used in the array. The airborne ultrasonic system according to item 5.