JPH0789400B2 - Emergency alert system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an emergency alert system, and more particularly to an emergency alert system capable of alerting a general vehicle to the approach of an emergency vehicle.

[Summary of the Invention] An electric wave and a sound wave such as a siren are transmitted from an emergency vehicle, and a general vehicle calculates the distance from the emergency vehicle from the phase difference (time difference) between the electric wave and the sound wave, and recognizes the approach of the emergency vehicle. It can be so.

[Prior Art] Conventionally, as a means for warning an approaching emergency vehicle to a running general vehicle, a method in which an emergency vehicle sounds a siren and travels is almost the most common.

However, with such a method using a siren, it is difficult to accurately determine the siren sound when listening to a car radio, a car stereo, or the like, or when the window is closed. Recent automobiles are particularly disadvantageous because they are designed to be quiet inside the vehicle.

Further, on highways and the like, noises such as road surface, engine, wind noise, etc. mask the siren noise.
Therefore, it has been developed for drivers of hearing-impaired vehicles by detecting siren sound from sound waves, but it is not at a practical level due to problems such as malfunctions and operational sensitivity that changes depending on the direction. Furthermore, with such a system, it is difficult to distinguish it from a siren in a factory, and it cannot be used when the siren sound changes.

As a solution to this inconvenience, a system using radio waves has been proposed. Such a system emits a radio wave that reaches a range of several hundred meters from an emergency vehicle, receives the radio wave on the general vehicle side, and issues a warning.

[Problems to be solved by the invention] However, in the conventional emergency alert system, the strength of the carrier depends on the surrounding conditions (influence of the building, etc.), and the shape of the car and the directivity due to the antenna are also added. There is a problem that it is difficult to give a proper instruction to the driver due to a large electric field change. Furthermore, since the approach of an emergency vehicle is detected depending on the reception strength, it cannot be determined whether the emergency vehicle is approaching or far away, and the original purpose of the emergency alert system is sufficiently achieved. I haven't.

It is an object of the present invention to provide an emergency alert system that allows the general vehicle side to know the distance between the general vehicle and the emergency vehicle, and further the direction.

[Means for Solving Problems] The above-described object is to mount a transmitter and a sound generator that send out a signal of a predetermined pattern on the emergency vehicle side, and to amplify the sound emitted by the emergency vehicle on the general vehicle side. This is achieved by including a processing system and a radio wave reception system, and calculating the distance by comparing the time difference between the envelope signal from the acoustic wave system and the detection envelope signal of the radio wave system.

[Operation] The phase difference between the sound wave system envelope signal and the radio wave system envelope signal is detected as a delay time. Thereby, the delay time is proportional to the distance, so that the position of the emergency vehicle can be accurately known.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 are block diagrams of a transmission system and a reception system showing an embodiment of the present invention. The transmission system is mounted on an emergency vehicle, and the reception system is mounted on a general vehicle. Further, as shown in FIG. 3, a trumpet speaker 61 that emits a siren sound as a sound wave is installed in the emergency vehicle 60, and microphones 71, 72 for capturing the siren sound are provided in the front and rear of the vehicle in the general vehicle 70. It is installed.

In FIG. 1, the transmission system is composed of a conventional siren generator / loudspeaker 1a and a radio wave generator 1b according to the present invention. The siren generation / loudspeaker 1a includes a siren sound generator 2 for generating a siren sound signal, a microphone amplifier 4 for amplifying the output of the microphone 3, and a power amplifier 5 for power-amplifying these outputs. The siren sound generator 2 is activated by turning on the siren switch S ₁ , and the siren sound is sent from the trumpet 61. When the press talk switch S ₂ attached to the microphone 3 is closed, the voice is amplified by the microphone amplifier 4 and the power amplifier 5 and output from the trumpet speaker 61.

On the other hand, in the radio wave generator 1b, a predetermined bit pattern is generated by the bit pattern switch 7 and the emergency signal generator 8 generates an emergency signal in response to this. Further, the data transmission unit 9 generates data such as vehicle speed and direction based on various sensors mounted on the vehicle. The outputs of the emergency signal generator 8 and the data transmitter 9 are transmitted via a modem 11 to a modulator 11
Sent to. Each output of the siren sound generator 2 and the microphone amplifier 4 is input to the modulator 11, and each output is subjected to a predetermined modulation and then output to the transmitter 12. The transmitter 12 radiates a radio wave based on the modulated signal from the antenna 62.

Next, the reception system, the reception signal captured by the reception antenna 21 provided on the roof of the general vehicle is amplified by the high frequency unit 22, after conversion, after intermediate frequency amplification in the intermediate frequency unit 23,
The wave is detected by the wave detector 24. The detected signal is separated into types of signals by the multiplex 25, the audio signal is output from the speaker 27 via the amplifier 26, and the siren sound is sent to the filter control circuit 29 and the frequency comparison unit 30 via the siren frequency detection unit 28. Sent out. Other signals are output via the modem 31, data signals are output to the data comparison signal decoding unit 33 via the data signal determination unit 32, and emergency signals are output to the switching unit 35 via the emergency signal determination unit 34. ,
Other control signals are switched via the control signal determination unit 37.
Output to 38.

On the other hand, the output of the microphone 71 (72) having the waveform as shown in FIG. 4 is amplified by the amplifier 39 and applied to the variable filter 40 via the switching unit 35. The variable filter 40 is configured by using a digital filter, a switched capacitor or the like, and outputs an output waveform as shown in FIG. In the case of a switched capacitor, the f ₀ of the filter is determined by the external clock, so the frequency is 5 or 10 times the frequency of the siren from the radio system. In the case of a digital filter, data corresponding to the siren frequency is sent from the microcomputer.

The output of the variable filter 40 is detected by the sound pressure level detecting section 41 as a sound pressure level having a waveform as shown in FIG. 7, and the detected value is sent to the comparing section 42 and compared with the set value. Comparison section
The electric field strength detection value of the electric field strength detection unit 43 is also input to 42,
Similar comparison is performed, and using the respective comparison results, the approximate distance detection unit 44
Calculates the approximate distance. On the other hand, the output of the variable filter 40 is waveform-shaped by the waveform shaping unit 45 and then applied to the periodic signal detection unit 46 and the siren frequency detection unit 47. The detection unit 46 detects the periodic signal, and the detection signal is applied to the period comparison unit 48. Further, the detection section 47 detects the siren frequency, and the detection signal is applied to the frequency comparison section 30. The cycle comparison unit 48 compares the output of the siren cycle detection unit 49 connected to the siren frequency detection unit 28 with the output of the detection unit 46, and outputs the comparison result to the distance detection unit 50.

The period comparison unit 48 compares the envelope of the radio wave system (output of the siren period detection unit 49) with the envelope of the sound wave system (output of the siren period signal detection unit 46) and detects the period deviation. The envelope has a waveform as shown in FIG. On the other hand, the carrier level (signal strength S) of the emergency signal output from the modem 31 is inversely proportional to the distance 1 as shown in FIG. Therefore, only when the level is higher than the set level (broken line in the figure), the output signal is generated from the emergency signal discriminating unit 34, the switching unit 35 is opened to activate the sound wave system, and the influence of malfunction or interference is eliminated. Incidentally, FIG. 9 shows an output waveform (siren waveform) of the siren frequency detector 28.

In the period comparison unit 48, the envelopes of the sound wave system and the radio wave system are
Compare as shown in the figure (broken line is sound wave system, solid line is radio wave system),
Calculate the delay time t _d . Distance detection unit based on this result
50 calculates the distance from the delay time t _{d as} shown in FIG. Note that some sirens have a long cycle, so the distance is calculated by comparing the siren frequencies (frequency comparison unit
30). In this case, whether the siren frequency is rising or falling is discriminated from the periodic signal, and if the periodic signal is HIGH, the siren frequency of the radio wave system is always high due to the rising. Conversely, LOW
The frequency of the radio wave system becomes low if it becomes and becomes descent.

By the way, the sound wave travels about 340 m per second, so at a distance of 34 m it should be delayed by 0.1 seconds, but for a siren with a fast frequency change, the period of one cycle is short, so the distance is longer than that time. If this happens, the distance detection will malfunction. In other words, with a 0.5-second cycle siren, the time difference becomes one cycle at a distance of about 340 m / 2 = 170 m, and the difference disappears with the envelope signal.

Therefore, the siren sound pressure level of the sound wave system and the electric field strength of the radio wave system are checked to determine whether it is 0 m or 170 m. 170 m
There is a large level difference between the distance of 0 m and the distance of 0 m, so it is possible to reliably judge. (Approximately -44.6dB down) The circuit for this is the detector
The circuit includes 41, 43, a comparison unit 42, and a rough distance detection unit 44.

Although the distance can be detected by the distance detector 50, what is important is that the warning level becomes low when the distance change is moving away even if the distance to the emergency vehicle is short. On the contrary, the same is true when approaching, and the distance change per unit time and the perspective are important.

The warning signal judgment unit 51 makes this judgment, and the output of the data comparison and decoding unit 33 is used as the judgment data, and the warning level is decided by checking the following items. Note that RO
M54 stores vehicle inspection data (vehicle number, vehicle name, etc.) of a general vehicle, and a data section 55 holds data detected by each sensor. In addition, at least part of the warning content is displayed on the display unit 52.
Is displayed in.

Distance between emergency car and ordinary car Change in distance between emergency car and ordinary car per unit time Distance between emergency car and ordinary car Based on these criteria, the following warning is issued via warning port 53 .

When an emergency vehicle approaches, the warning lamp blinks as the first level, and the blinking time is changed according to the distance.

At the second level, a warning is given by sound, and a warning sound or a voice synthesis sound is given. In addition, muting of car radio and car stereo will be performed together.

At the third level, the system is designed so that the instruction voice from the emergency vehicle can be heard through the speaker inside the vehicle and, if necessary, the sound outside the vehicle can be heard. At this level, the volume of car stereo, car radio, etc. is muted.

If the safety is sufficiently confirmed, the above warning will be reset manually.
However, normal operation can also be performed.

If you want to determine the direction in addition to the distance of the emergency vehicle, compare the vehicle speed with the general vehicle and the traveling direction from the data such as the vehicle speed and traveling direction of the emergency vehicle included in the data signal, and determine the approximate direction. I can confirm. Further, the Doppler effect can be used for correction, and the accuracy is improved.

In the above embodiments, the emergency vehicle warning system has been described as an example, but it is also effective for systematization in the following fields.

(1) By installing a transmitter at the entrance of a tunnel or at a dangerous place, warning by radio waves is possible (operation by radio waves only).

For example, even if an accident or the like occurs in the tunnel, a vehicle outside the tunnel may be warned in advance of the accident or the like.

(2) Since a regular car is always ready to receive radio waves, it is possible to build a traffic system for cautioning, slowing down, stopping, and instructing general drivers. Also, since it has a ROM inside, it can be specified individually from the license plate (variable bit pattern).

(3) Application to earthquake warning system. By transmitting a warning to a general vehicle using satellite communication or the like, it is possible to automatically issue a warning without providing an emergency broadcast receiver.

(4) Since this system can also give a stop instruction only by radio waves, it automatically checks the speeding vehicle from the license plate and causes the compatible vehicle to blink 4 lights of the direction indicator. A system for issuing a stop instruction can also be configured. Currently, to stop a speeding vehicle, a red light or red flag is waving to give instructions, but it is very dangerous. However, by applying this system and instructing compatible vehicles, it is possible to reliably give a stop instruction. Direction indicator 4
Since the light blinks, it can be discriminated from other vehicles at a glance, which is effective in preventing escape.

[Effects of the Invention] As described above, according to the present invention, the distance can be calculated from the time difference between the acoustic signals of the sound waves and the radio waves, so that the general vehicle can accurately establish the relationship with the emergency vehicle. It is possible to grasp and contribute to safe driving.

The emergency signal is performed by matching the bit pattern,
Since the electric field strength, sound pressure level, etc. are checked, malfunctions and interference can be prevented and reliability can be improved. Furthermore, since the direction of the emergency vehicle can be known by using the data signal, it is possible to provide effective information particularly to a general vehicle located at an intersection or the like and improve safety.

Moreover, since sound waves are used in addition to sound waves, the sound pressure level of the siren can be lowered in accordance with noise regulations and the like, which also contributes to noise pollution countermeasures.

Further, since the warning can be given by the lamp, it is possible to surely warn the driver of the hearing loss that the emergency vehicle is approaching.

[Brief description of drawings]

1 and 2 are block diagrams of a transmission system and a reception system showing an embodiment of the present invention, FIG. 3 is an explanatory diagram showing a relationship between a vehicle and the system, FIG. 4 is an output waveform diagram of a microphone, and FIG. 5
6 is an output waveform diagram of the variable filter 40, FIG. 6 is an envelope waveform diagram, FIG. 7 is a sound pressure level characteristic diagram of a siren sound, FIG. 8 is a carrier waveform diagram of an emergency signal, and FIG. 9 is a siren frequency detection unit. 28 is an output waveform diagram, FIG. 10 is an envelope comparison waveform diagram, and FIG. 11 is a phase difference signal characteristic diagram. 1a …… Siren generator / loudspeaker, 1b …… Radio wave generator, 2 …… Siren sound generator, 7 …… Bit pattern switcher, 8 …… Emergency signal generator, 9 …… Data transmitter, 12 …… Transmitter, 21 ... Antenna, 22 ... High frequency section, 23 ... Intermediate frequency section, 24 ... Detection section, 25 ... Multiplex, 28 ... Siren frequency detection section, 29 ... Filter control circuit, 30 ... … Frequency comparison section, 31 …… Modem, 32 …… Data signal discrimination section, 33 …… Data comparison signal decoding section, 34 …… Emergency signal discrimination section, 40 …… Variable filter, 41 …… Sound pressure level detection section, 42 …… Comparison section, 43 …… Field strength detection section, 44 …… Approximate distance detection section, 46 …… Period signal detection section, 47 …… Siren frequency detection section, 48 …… Cycle comparison section, 49 …… Siren cycle Detection unit, 50 ... Distance detection unit, 51 ... Warning signal determination unit, 52 ... Display unit, 53 ... Warning Over door.

Claims (3)

[Claims] 1. An emergency vehicle is equipped with a transmission system for emitting sound waves and a predetermined pattern of radio waves, and a reception system for receiving the sound waves and the radio waves is mounted on a general vehicle, and an envelope of received sound waves and an envelope of received waves are provided. An emergency alert system, wherein the distance to the emergency vehicle is calculated based on the phase difference of the above. 2. A time difference between the electric field strength change of the radio wave, the sound pressure level change of the sound wave, and the change of the sound wave frequency is detected to prevent malfunction of the distance calculation. The emergency alert system according to claim 1. 3. The direction and relative distance of the emergency vehicle are calculated by transmitting data such as vehicle speed and traveling direction from the emergency vehicle and comparing the data with the data held in the own vehicle in the general vehicle. The emergency alert system according to claim 1.