JP2565883B2 - Underwater reporting device - Google Patents

Description

Description: [Industrial field of use] The present invention relates to an underwater fall notification device configured for a pulse radar device mounted on a ship.

[Prior Art] In recent years, targeting 9 GHz band radar mounted on ships and aircraft, search and rescue radar transponders (hereinafter referred to as transponders) equipped on ships, lifeboats mounted on ships, life rafts, etc. (Abbreviated) will be put to practical use, and in Japan, the floating transponder as a practical testing station has already been licensed in Japan, and some fishing boats are equipped with it. This utility is based on IMO (International M
aritime Organization ... International Maritime Organization)
IMO COM 31 / WP.1, Annex 5 has already been used for survival boat radar
The transponder performance requirements have been resolved.

This is based on CCIR's recommendation [AE / 8] [TECNICAL CHARA
CTERISTICS FOR SEACH AND RESCUERADAR TRANSPONDER
In addition to the main items in [S], the requirements that must be met for operation are added.

Here, in order to help understanding of the present invention, a document describing the contents of the transponder of the practical use test station will be introduced, and a specific example of the transponder system will be described.

The most recent ones are the monthly magazine `` Shipbuilding Technology '', '85 / 11, vol.
18no.11 P44 to P51 have the description.

Currently, P48-P
Although it is 51, the former one is also functionally equivalent and will be approved after some revision.

Here, regarding one embodiment of the transponder which has already been put into practical use, the system diagram of FIG. 6, the waveform diagram of each main part of FIG. 7, and the PP of the target radar device are shown in FIGS. 8 and 9.
The pattern of the display displayed on I will be illustrated and described.

In the following, the reference numerals shown in each of FIGS. 1 to 9 indicate the same or corresponding portions.

In FIG. 6, (1) is a horizontally polarized wave receiving antenna having omnidirectional characteristics in the horizontal plane, and the transmitting antenna (12) is also substantially the same. (2) is a microwave detector having a wide band characteristic, (3) is a video amplifier, and the radar wave (a) arriving here is detected and amplified to obtain a system trigger pulse (b). (4) is a NAND date,
(5) is a monostable multivibrator that simultaneously generates a sneak-in prevention gate (d) and a transmission gate (c).

The gate width (G) of this transmission gate (c) is almost 100.
In μs, the sneak prevention gate (d) is designed to be long by (dT) using (L) in the waveform (d) of FIG. 7 as a threshold value.

The description of this operation is almost similar to that described in Japanese Utility Model Publication No. 55-37905, and therefore detailed description thereof will be omitted.

(6) is a combination of a self-propelled timer and a lamp driver, (7) is a lamp that also serves as a marker lamp, (8)
Is an electronic switch using a transistor, etc., (9) is a power supply unit combining a battery, a voltage stabilizing circuit and a mercury switch, (10) is an electronic tuning microwave FM oscillator using a combination of GaAs-FET and a variable capacitance diode, (11) Is a sawtooth wave voltage device for obtaining a high-speed frequency sweeping radio wave (g) synchronized with the transmission gate (c) by the sawtooth waveform (f).

In FIG. 7, (V) is voltage, (T) is time, and (F) is
Is a frequency, and (t) is approximately 5 in this transponder.
μs, (F _o ) is 9410 MHz, and (dF) is approximately 180 MHz.

Therefore, this transponder has a transmit / receive frequency of 93
Response waves can be returned to all radars existing between 20-9500MHz.

FIG. 8 shows an example of a general echo and the PPI display status after the response returned from this transponder.

The position of the radar antenna is the center of the screen, and point (x) is the relative distance at which this transponder is present. The linear wave of the prip is displayed behind that distance is the response wave from this transponder. The azimuth width of the response wave is governed by the beam width (θ) of the radar antenna, that is, the azimuth resolution, and the blip interval (t) is approximately 5 μs (150 m / μs converted to the velocity of the radar radio wave, approximately 750).
m), the width of each prep (τe) is approximately expressed by the following equation, and this value is close to the pulse width (τ) of the radar wave of the waveform (a) in FIG. 7 or more than that. Larger should give better results.

(Τe) = (t) · B / (2F) (1) Equation ∴B is the reception passband of the target radar, and the unit is Hz with (dF), and the units of (τe) and (t) are both It is sand.

Here, the point (X) has a maximum range error of about 5 μs (maximum range of about 5 μs) depending on which frequency the radar transmits / receives.
(Equivalent to 750 m) will occur, but since it represents that the transponder is surely present in the direction of the blip row, the rescue side should proceed in the direction of the blip row.

When it approaches further, it responds not only to the main beam of the radar antenna but also to minor lobes such as side lobes and back lobes, so that an image close to a circular arc as shown in FIG. 9 is drawn.

Note that FIG. 9 shows a situation in which the observation radius is smaller than that in FIG. 8, and therefore (τe) and (t) are large.

The above transponder is always in the non-operating state because the power is cut off by the mercury switch of the power supply section (9), but in an emergency, it is dropped in the sea and floats, and the mercury switch automatically turns on the power. .

If there is no irradiation of radar radio waves (a),
The combination of the self-propelled timer and the lamp driver in (6) immediately starts operating, and the indicator lamp in (7) blinks with the repetition of the time ratio of lighting for about 0.5 seconds and resting for about 4.5 seconds. .

When the radar wave (a) is emitted, the waveform of logic "1" corresponding to the time (G) of the waveform (c) of FIG. 7 generated according to the number of the radar wave (a) emitted is Presence of radar radio waves by irregularly interrupting the combination of the self-propelled timer and the lamp driver in (6) above and changing the regular blinking of the indicator lamp.
That is, it is possible to inform the victim of the approach of a rescue ship or the like.

This pattern is similar to the arc-shaped radar PPI image in Fig. 9, and the lighting time becomes longer as the distance between them becomes smaller, and it automatically changes to a state of almost continuous lighting. It can help psychologically.

[Problems to be solved by the invention]

As described above, the conventional transponder system can report the fact of distress without modifying the existing radar device, and by using the symbol that is not confused with the symbol of the existing radio beacon device, and can approach the exact location. It is extremely useful, but it is thought that there are facts that contradict the context in various operational situations at sea. For example: (1) Is the transmission pulse emitted even if the radar antenna is rotated? That is, since the magnetron of the transmission signal source is expensive and its life is relatively short, the emission of the transmission pulse may be stopped when the radar image is not required.

(2) Do you constantly observe radar images even if the transmission pulse is emitted? Rather, it is mainly for maneuvering and watching, and it may be the normal situation to observe radar images from time to time. it is conceivable that.

Even if the transponder waits for activation or emits a response radio wave, it cannot be rescued unless it is observed by the radar side.

At the present time, IMO is using FGMDSS, which utilizes recent sanitary communication technology, to improve the safety of human life at sea.
(Future Global Maritime Distress and Safety Syste
m; Future global salvage safety system) 1990
Work is in progress to introduce it from the year.

Compared to the current communication system using a manually operated wireless telephone, this system automates communication, makes it global, and introduces EPIRB (emergency position indicating radio beacon) to search for marine accidents and improve the efficiency of rescue. It is an innovative system for the safety of navigation.

Actually, in this EPIRB, adoption of the transponder for the purpose of pinpoint rescue is considered in addition to the VHF or UHF band distress notification means.

However, it is difficult to apply the EPIRB device that can be considered in the field to accidents where an individual accidentally falls into the sea while operating on a ship and is lost.

The reason is that it is physically impossible for an individual to carry the device and configure it in a size that does not interfere with normal work.

Unfortunately, in spite of the large number of fishing accidents and shipping accidents occurring in the sea, the precious lives of people have been lost without obtaining accurate reporting methods and evidence.

Even if a ship is given a stop command during navigation, the ship is normally 10
It is said that it will move twice as long, and it will take a considerable time before it detours and rounds to the expected sea level. Furthermore, if the discovery of a fall is delayed for a while, and if the search takes more time, the probability of rescue will be extremely low.

The present invention has been made to solve the above drawbacks, and at least the target radar device of the own ship is provided with a commanding device for receiving the underwater drop information and notifying the occurrence of an accident in the ship. In order to obtain a wristwatch or a sea-fall report device having a shape similar to that of a wrist watch equipped with means for automatically reporting a sea-fall in the same frequency band as the condition, using the basic part of the transponder system. With the goal.

[Means for solving problems]

The undersea fall notification device according to the present invention includes a base to which a belt of a wristwatch is attached, an antenna in which a half-wavelength slot is formed in a conductor plate arranged on the base, the base and the conductor plate. And a detector for detecting the microwave received by the antenna, a video amplifier for amplifying the output of the detector, and a frequency sweep in a predetermined frequency range, and a radio wave to be transmitted from the antenna. A conductive substrate having a microwave oscillator for radiating into space,
A pulse generation circuit that outputs a transmission gate signal by a system trigger pulse output from the video amplifier, and outputs a drive signal that is supplied with the transmission gate signal from the pulse generation circuit and that causes the microwave oscillator to start frequency sweeping. An electronic switch, a sawtooth wave voltage generator that receives the drive signal from the electronic switch to generate a sawtooth wave voltage, and outputs the sawtooth wave voltage to the microwave oscillator, and supplies an output to the electronic switch for a predetermined time in an emergency. Then, a timer for driving the sawtooth wave voltage generator and the microwave oscillator to radiate a high-speed frequency sweeping radio wave within the predetermined frequency range from the antenna to the space is mounted, the conductive substrate and the base. An insulating film substrate provided between the antenna, the conductive substrate, and the insulating film substrate. It is obtained by a water capable radome.

[Operation] Since the underwater fall reporting device according to the present invention is configured as a wristwatch type in which the timer is provided in the configuration of the conventional radar transponder, it is possible to report in the event of an underwater fall and the conductive substrate is an antenna. It is also possible to use it as a reflection plate of the above, and by using an insulating film substrate on which the above timer and the like are mounted, it is possible to attach it with a slight bend.

Example of Invention

In the following, first, a system diagram of one embodiment of the underwater fall notification device according to the present invention is shown in FIG. 1, and a waveform diagram for explaining the operation of a subordinate portion derived by adding an additional circuit is shown in FIG. Fig. 3 shows a system diagram of an embodiment of an additional device to be added to the radar device, and Fig. 4 shows waveform diagrams of the respective main parts to explain the mutual operation. Fig. 5 particularly shows the antenna system. The feasibility will be described with reference to a perspective view showing an embodiment of a wristwatch type of the underwater fall reporting device, focusing on the miniaturization of the above.

First, although (1) in FIG. 1 is still a receiving antenna, it is not obsessed with the above-mentioned omnidirectionality in the horizontal plane, and as shown in FIG. A unidirectional one using a reflector is used. The transmitting antenna of (12) is exactly the same. The reference numerals (2), (3), (4), (5), (8), (10) and (11) in FIG. 1 are the same as those in FIG. (9) is a power supply unit in which a battery and a voltage stabilizing circuit are combined, but it may be a good idea to change the above-mentioned mercury switch to a magnetically responsive reed switch (proximity switch) for miniaturization. In addition, a lithium battery or a seawater battery, which has good storage stability, is suitable as the battery.

Various types of seawater batteries are already on the market, and most are used as power sources for marker lights of inflatable liferafts.
A seawater battery is a primary battery, which is put into the sea at the time of use and uses seawater as an electrolytic solution, so that it has excellent storage stability at all times and is easy to reduce in weight. In this case, no switch is required.

(21) is a timer with a monostable multivibrator that opens the gate for about tens of seconds after power is applied.
As in the second waveform (H), the power source is activated from the ON time, and the logic "1" is maintained during the time (S).

Reference numeral (22) is an isolator in which two diodes are combined to pass the waveform (c) of FIG. 7 or the waveform (H) of FIG.

Therefore, a gate signal of logic "1" is introduced from the timer (21) to the electronic switch (8) for about tens of seconds after the power is applied (when the seawater battery is put into the sea), and the transponder described above is introduced. An electronic tuning microwave FM oscillator (10) and a sawtooth wave voltage generator (1
1) is excited at the same time and the waveform (f ') in FIG.
(G ') is derived.

This high-speed frequency sweep radio wave (g ') is not synchronized with the radar pulse, but the frequency sweep range is the same as in the transponder described above.

Also, the "integration of radar pulse" based on the number of pulse hits as described later cannot be obtained, and it is difficult to display it as a clear symbol on the radar indicator, but in the radar receiver, as in the case of the transponder described above. Should be received.

Here, a supplementary explanation will be added on the time setting of the timer.

The waveform (a) of FIG. 2 has a longer time axis than the waveform (a) of FIG. 7 and realizes a pulse train radio wave that the radar radio wave radiates from the beam width (θ) in the horizontal plane of the antenna and reaches it. Normally, the antenna receives signals every few seconds by continuously rotating and scanning the antenna in a horizontal plane by 360 degrees.

On the other hand, the pulse repetition frequency of the radar system is set in consideration of its maximum detection distance, and when trying to find the target with the radar, usually many pulses are reflected from the target each time the antenna scans, Ability is improved. When the radar antenna scans, the property of the pulse reflected from a single point target within the beam ... Usually called the number of pulse hits.

If ... is n The process of adding all of these radar reflection pulses to improve the detection ability is called “integration of radar pulse”, which usually depends on the radar indicator and the eyes and brain of the observer. There is.

 Here, θ = antenna beam width at half power point (degrees) fr = pulse repetition frequency (Hz) ω = antenna rotation speed (rpm).

Most of the ship radars have a horizontal plane θ of 1-2 degrees, fr
= 500 to 3000 Hz, ω = 10 to 30 rpm, and assuming that the minimum value of the radar antenna rotation speed is 10 rpm, the value of "about several tens of seconds" is 6 seconds + radar antenna vertical plane orientation. Choose a time that takes ship speed into consideration to reach the coverage area. That is, it is only necessary to select the high-speed frequency sweeping radio wave (g ') to be received by the radar even if the timer (21) is activated under any circumstances.

For example, ship side 10 kt, captain 50 m, radar antenna height 20
m, assuming that the antenna's vertical in-plane directivity is 20 degrees, approximately 160
It takes about 40 seconds to enter the coverage area at a distance of m.

If this radio wave is received on the radar side, as will be described later, it will be detected and an alarm sound will be issued to inform the ship of the fact that it has fallen into the sea, and if radar transmission is stopped, this will be automatically transmitted at the same time. I should let them do it. Immediately after entering radar observation, at this time, since the underwater fall reporting device has already been automatically switched to the conventional transponder function, it is possible to quickly approach the fallen person.

Next, an example of the radar addition device will be described.

Fig. 3 is a "figure" described on page 5 of Radar Technology [Part 1] published by The Institute of Electronics and Communication Engineers of Japan (first edition issued April 20, 1968).
1.2 System diagram of a typical pulse radar ”, and the radar video signal is branched from the point Y added in this figure.
Further, the additional device using means for branching the system trigger signal from the Z point will be described.

Although the operation surface of the radar device is omitted in this figure, in the actual radar device, mainly on the panel surface of the indicator, in addition to the main power switch, transmission switch, antenna rotation switch, observation distance changeover switch, etc. Equipped with various adjustment knobs.

In addition, the A scope is rarely used in marine radar.

In FIG. 3, (31) and (32) are respective input buffer circuits, which are intended to be converted into a circuit having a high input impedance so that the video signal of the radar device and the system trigger signal are not distorted. In particular, the input buffer circuit of (31) should be able to obtain good results with a voltage comparator in the video frequency range that allows waveform shaping while eliminating noise contained in the video signal, or a gate IC with a Schmitt function. .

(33) is a monostable multivibrator for deriving a delay trigger, and obtains the waveform (h) in FIG. If this time (D) is selected in the vicinity of the time corresponding to the maximum detection distance of the radar indicator, it will not be confused with the reflected video signal even during radar transmission, and as will be described later, the high-speed frequency sweeping radio wave ( The pulse counting of g ') becomes easy.

Similarly, (34) is also a monostable multivibrator, which is activated from the falling time of the waveform (h) in FIG. 4 and creates the gate (j) for pulse counting. This time (k) is
The time constant may be set so that it is stopped before the next system trigger rises, or it may be reset by this system trigger or pre-trigger (not shown).

(35) is a 2-input AND gate and the waveform (m) in FIG.
Derive. That is, the high-speed frequency sweeping radio wave (g ')
Takes out what is input as a video signal (Y) through the receiving section of the radar within the section of time (k). (36) is a first pulse counter, which measures the number of pulses during the time (k) and derives the waveform (n) in FIG. The frequency division ratio in this case is such that the pulse interval (t) of the waveform (Y) in FIG.
Since it is s, it may be set in consideration of the time (k).

The waveform (n) in FIG. 4 corresponds to the second AND gate (3
7), which is regulated by the output waveform (q) of the monostable multivibrator (38) and confirms with a hit number equivalent to or slightly smaller than the pulse hit number, that is, a second pulse counter (39). ), The waveform (u) of the divided pulse is extracted.

This means does not judge the fact that the high-speed frequency sweeping radio wave (g ') is emitted based on the presence or absence of only a series of pulse train signals / waveforms (m) or waveforms (n), but determines the number of pulse hits. Obtain a close count and try to recognize this.

The reason for this is to avoid interference from various communication measuring instruments mounted on the ship, or to prevent malfunction due to reception of radar waves from other ships.

(40) is a driver for obtaining a contact signal of a relay or the like after the waveform (u) of FIG. 4 is derived, (41) is a relay, (2) is an alarm sound generator, and (43) is onboard a ship. A confirmation device for notifying an alarm sound to the alarm sound generator (42) may be connected from the alarm sound generator (42) if the same kind is already installed in the ship.

Also, if another contact signal (w) of the relay (41) is connected in parallel with the transmission switch of the radar, automatic transmission becomes possible.

As described above, it is possible to obtain information on the underwater fall by branching and connecting an additional device of a relatively simple scale to the conventional radar device.

It should be noted that the reset pulse and the latch pulse, which are naturally necessary for the counting process, and the illustration of the power supply connection to each circuit, etc., are not necessary as the essence of the present description in FIGS. Omitted.

Next, a perspective view of the embodiment shown in FIG. 5 will be described with respect to the possibility of realizing the above-mentioned underwater fall reporting device as a wristwatch.

Since an ordinary person wears a watch on his left arm, the apparatus shown in FIG. 5 is shown with all the devices worn on the right arm side.

In FIG. 5, (1) and (12) are antennas having a Bat wing type conductor surface provided with thin slots of about wavelength, and the slot length in this frequency band is about 16 mm.

As the power is fed to the center, the impedance at the feeding point is about 400Ω including the imaginary part in the free space, but if a reflector is provided and the slot length is adjusted slightly, the 50Ω microwave Can be directly connected to the IC circuit (MIC).

Further, the directivity can be changed from the original 8-shape to a unidirectional directivity, and it can be avoided due to the influence of the arm. (2), (3),
(10) is a circuit of the same type as described in Fig. 6 at the beginning, with a thickness of about
It is mounted on a strip line provided on an alumina base material of about 0.5 mm.

Since the back surface of this alumina base material is a thin conductor film, keep the distance from the slot antenna in (1) and (12) above.
It can be used as a reflector if it is separated by about 0.15 to 0.25 wavelength.

(51) is a radome made of thin hard resin, (52) is a case where a conductive film is plated on the back surface of the same hard resin, (53)
Is a shield for reducing the interference between the slot antennas (1) and (12), (54) is the NAND gate (4), monostable multivibrator (5), electronic switch (8), sawtooth wave of FIG. It is a film substrate made of a polymer resin in which a voltage generator (11), a timer (21), an isolator (22), a power supply voltage stabilizing circuit, etc. are integrated and attached, and the film substrate can be attached with a slight bend.

(55) is a base made of hard resin.
8) is included. (56) is the above-mentioned proximity switch for connecting / disconnecting the battery power supply. (56) is a magnet unit, and in the structure of this figure, slides back and forth to connect / disconnect the battery power supply.

(59) is a belt for the waterproof battery unit (60), which is integrally attached to the battery unit. The case of the battery unit (60) is slightly curved to fit under the arm of the body.

When this belt (59) is worn from the left shape (lower left of neck) to the armpit under the right arm, the battery unit (60) fits under the armpit of the right arm, and the workability is minimized. (62)
Is a two-core cable for the battery power supply and has a two-pole connector (61) with a waterproof rubber plug attached to the end on the battery side.

The size of an ordinary men's watch is about the diameter of the watch itself.
36mm, the length of the belt mounting part is about 40mm, and the thickness is around 10mm, but the design size of the "watch" part of this device is slightly larger than this, and its approximate size is 35mm x 45mm, thickness 14
It is expected to be about mm.

Also, the battery unit (60) where size and weight are most concerned.
Assuming that 3 AA size manganese dioxide lithium batteries with an elementary voltage of 3V are used, the weight is about 70g excluding 48mm x 60mm, thickness 20mm and belt (59), and the water temperature is 0 ° C in the sea. Even if it falls, the notification can be transmitted for about 3 hours, and it is expected to have sufficient practicality.

Here, a supplementary explanation will be added on the correspondence between the directivity of the slot antennas (1) and (12) and the polarization plane of the target radar antenna.

As already mentioned, the slot antenna (1),
(12) is unidirectional, but when a person who falls into the sea desperately starts swimming, his or her arms move in and out of the surface of the sea, and the directivity cannot be determined. However, there is always a case where the main directivity is directed to the radar antenna during the movement of the arm, and its speed is considerably slower than the transmission time of the information, so it is not necessary to pay attention to directivity and polarization plane. Become.

However, it is unavoidable that the contact rate with the radar antenna will decrease, but it is not considered necessary to discuss the reduction of the reach distance due to the inclination of the polarization plane and the deviation from the directivity at the shortest distance.

Rather, if the direction and distance of a person who has fallen into the sea can be found even once during the search, it becomes possible to approach the person quickly and accurately as in the case of the transponder.

Although the fixing tool between the elements is omitted in the embodiment shown in FIG. 5, it goes without saying that the fixing tool is provided if necessary. Although not shown in the figure, it is desirable to provide a yellow or orange indicator lamp that emits light at the same time when the power is turned on for the final confirmation of the search side at night or in the thick fog (also for confirmation of a person who has fallen into the sea).

Although the above-mentioned embodiments have consistently described means for coping with an underwater accident, it is needless to say that if a similar means is adopted for a conventional transponder, a more effective one can be developed.

〔The invention's effect〕

As described above, according to the present invention, a timer is provided in which an output is supplied to the electronic switch for a predetermined time in an emergency and a high-speed frequency sweeping radio wave within a predetermined frequency range is radiated from the antenna to the space, and the wristwatch type. Therefore, it can be carried at all times, and by using the above timer in an emergency such as a fall in the sea, it is possible to save lives more quickly, and the conductive substrate can be used as the reflector of the antenna to provide unidirectionality. When falling into the sea, moving the arm can radiate radio waves in all directions, and the use of an insulating film plate has the effect of facilitating assembly.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the underwater fall reporting device according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the main extraction unit of FIG. FIG. 7 is a description of the search / rescue radar / transponder of FIG. 7 with the equivalent portions deleted from the waveform diagrams of the respective portions of FIG. 7 for explaining the operation of the system diagram of one embodiment. FIG. 3 is a system diagram showing an embodiment of a radar-added device for receiving and processing a sea-fall report sent from the sea-fall report device of FIG. 1, and FIG. 4 is each part of FIG. FIG. 5 is a perspective view showing one embodiment for explaining that the wristwatch can be actually realized from the system diagram of one embodiment of the underwater fall reporting device shown in FIG. 1. Fig. 6 and Fig. 6 show the search and
Fig. 7 is a system diagram showing a rescue radar transponder, Fig. 7 is a waveform diagram showing the operating condition of each part of Fig. 6, and 8
Figures and 9 are examples of images of the above-mentioned search / rescue radar / transponder displayed on the radar PPI. In particular, Figure 9 shows the relative distance between the radar and the search / rescue radar / transponder. This is an example of an image that is likely to occur at a close range. In FIG. 1, (21) is a timer that operates for a short period of time after power is applied, and (22) is an isolator that combines two diodes. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A base to which a wristwatch-shaped belt is attached,
An antenna in which a half-wavelength slot is formed in a conductor plate arranged on the base, a detector provided between the base and the conductor plate, for detecting a microwave received by the antenna, A video amplifier for amplifying the output of the detector and a conductive substrate having a microwave oscillator for performing frequency sweep in a predetermined frequency range to radiate a radio wave to be transmitted from the antenna into space, and a system trigger from the video amplifier. A pulse generation circuit that outputs a transmission gate signal by pulse output, an electronic switch that is supplied with the transmission gate signal from the pulse generation circuit and outputs a drive signal that causes the microwave oscillator to start frequency sweep,
The sawtooth wave voltage generator which is supplied with the drive signal from the electronic switch to generate a sawtooth wave voltage and outputs the sawtooth wave voltage to the microwave oscillator, and supplies the output to the electronic switch for a predetermined time in an emergency. A timer for driving the linear wave voltage generator and the microwave oscillator to radiate a high-speed frequency sweep radio wave within the predetermined frequency range from the antenna to the space is provided, and between the conductive substrate and the base. An underwater fall reporting device comprising: an insulating film substrate provided; and a waterproof radome that surrounds the antenna, the conductive substrate, and the insulating film substrate.