JPH0823920B2 - Aircraft detector - Google Patents

Description

TECHNICAL FIELD The present invention provides a plurality of sound-electric conversion transducers having sensitivity in a high frequency region and different sensitivity frequencies in the vicinity of a ground taxiway, and each high frequency of these transducers. By using the logical sum of the detection outputs as the detection output, it is possible to ensure the approach of the aircraft on the taxiway without being affected by the noise of other aircraft passing through taxiways other than the taxiway or the aircraft taking off and landing. It is designed so that it can be detected.

2. Description of the Related Art In a taxiway, an audible frequency noise type sound meter is used as a means for collecting information such as aircraft approaching, and means for judging aircraft approaching from the output level of this sound level meter is conceivable. For example, as shown in FIG. 6, a transducer 1 having sensitivity in the audible frequency range is installed near the guide path,
After the output signal of the transducer 1 is amplified by the amplifier 2, the envelope detector 3 performs envelope detection and the level determiner 4 determines the level.

Problems to be Solved by the Invention However, when trying to detect the approach of an aircraft on an actual taxiway using an audio frequency sound level meter, the noise of an aircraft passing through another taxiway or the noise of another aircraft taking off and landing The noise
Since there is not much difference from the noise when the aircraft passing through the taxiway approaches, it turns out that it is difficult to detect the approach of the aircraft passing through the taxiway separately from the noise emitted by other aircraft. Was.

Fig. 7 shows noise data when a transducer is placed on Runway A at Haneda Airport to detect the approach of a Boeing 747 passing through Runway A. The horizontal axis shows the time axis and the vertical axis shows the noise level ( dB). The Boeing 747 passing through the runway A gradually approaches the transducer from a position away from the transducer, and the noise level becomes higher as it approaches, and a certain noise level is maintained in front of the transducer in the order of head, wing, and tail. Go through.

However, when the Boeing 747 passing the A runway approached a distance of about 100 m to the transducer, DC9 started from the C runway, so the noise generated by the DC9 was received by the transducer, and the Boeing that originally passed the A runway. The noise detection level of the transducer equipped to detect the noise level of the 747 is rapidly increasing. Therefore, it is very difficult to detect the approach of the Boeing 747 passing through the A runway separately from the noise generated by DC9 passing through the C runway.

Means for Solving the Problems In order to solve the above-mentioned problems, the aircraft detector according to the present invention, as shown in FIG. 1, has sensitivity in the high frequency region near the ground taxiway 6 of the aircraft 5. Having a plurality of sound-electric conversion transducers 71, 72 having different sensitivity frequencies,
It is characterized in that the logical sum of the high frequency detection outputs of these transducers 71 and 72 is used as the detection output P ₀ .

Action When looking at the noise emitted by an aircraft in the frequency spectrum, it was found that components in the high frequency region of 20 KHz or higher, for example, were hardly received when the distance between the noise source and the transducer was large. 2 to 4 show the distance from the aircraft to the transducer and the frequency spectrum of the noise received by the transducer at that time. Fig. 2 shows the frequency spectrum when the distance from the aircraft to the transducer is 200m to 400m, Fig. 3 shows the frequency spectrum when the distance is also 50m, and Fig. 4 shows the frequency spectrum when the aircraft is in front of the transducer. Shows. The data in Figures 2-4 show the noise of the Boeing 747 passing through Runway A at Haneda Airport.
It was obtained by a transducer placed near the A runway.

As shown in Fig. 2, when the distance from the transducer to the aircraft is long, such as 200 to 400m, the reception level of the noise component in the low frequency range becomes relatively high, but the reception level of the noise component in the high frequency range becomes relatively high. Is significantly reduced. This means that the high-frequency component of noise emitted by an aircraft passing through another taxiway or an aircraft taking off and landing on a taxiway different from the taxiway is received by the transducer because the distance to the transducer is long. Means not to be done.

However, as is clear from FIGS. 3 and 4, as the aircraft approaches the transducer, the reception level in the high frequency range sharply increases. Therefore, when a transducer with sensitivity in the high frequency region is placed near the ground taxiway of an aircraft, the high frequency component of the noise emitted by the aircraft passing through the taxiway with a short distance to the transducer is detected and its approach is detected. I can know.

Eventually, the approach of the aircraft on the taxiway can be detected without being affected by the noise of other aircraft passing through taxiways other than the taxiway or the aircraft taking off and landing.

Next, aircraft noise is mainly generated from the engine, and its high-frequency component varies depending on the aircraft model. Further, when a sound-electric conversion element such as a general piezoelectric ceramic is used as the transducer, the pass band becomes narrow. Therefore, in the present invention, a plurality of high-frequency detecting transducers having different sensitivity frequencies are provided, and the logical sum of the high-frequency detection outputs of the plurality of transducers is used as the detection output to solve the above problem.

Embodiment FIG. 1 is a diagram showing a configuration of an aircraft detector according to the present invention. Reference numeral 5 is an aircraft, 6 is a ground taxiway, 71 and 72 are transducers, 81 and 82 are amplifiers, 91 and 92 are detectors, and 10 is an OR circuit.

The transducers 71, 72 are sound-electricity conversion elements made of piezoelectric ceramic or the like having a sensitivity in a frequency region of 15 KHz or higher, for example. Transducers 71 and 72 have different sensitivity frequencies. For example, the transducer 71 is 15KHz
If it is sensitive to
The 72 are different from each other, for example, they have a sensitivity of 21 KHz. These transducers 71, 72
Are arranged on both sides of the taxiway 6.

The aircraft 5 passes through the taxiway 6, and the transducer 71,
The closer to 72, the higher the reception level of the transducers 71, 72 in the high frequency range. Transducers 71, 72
The respective high frequency detection signals of are amplified by the amplification circuits 81 and 82, detected by the detection circuits 91 and 92, and input to the logical sum circuit 10.
Then, the logical sum circuit 10 outputs the logical sum output P ₀ of the high frequency detection outputs of the transducers 71 and 72. As a result, the approach of the aircraft 5 passing through the taxiway 6 is detected.

Moreover, since the logical sum of the high frequency detection outputs of the plurality of transducers 71 and 72 is used as the detection output P ₀ , the aircraft 5
Even when the model changes like the YS-11 or Boeing 747 and the high frequency components included in the noise differ, the transducers 71 and 72 can also be used for sound-electric conversion of general piezoelectric ceramics with a narrow pass band. Even if an element is used, it can be detected reliably.

High-frequency components of noise emitted by an aircraft passing through another taxiway or an aircraft taking off and landing on a taxiway different from the taxiway are increased by the transducers 71, 72 because the distance to the transducers 71, 72 becomes long. Is rarely received.

By the way, the propagation direction of sound depends on the direction of the wind. When the noise generated from the aircraft 5 is received by the transducers 71 and 72 in the vicinity of the taxiway 6,
As shown in FIG. 5, the direction of the wind is changed by the transducer 71,
When the wind blows in the direction V ₁ which is perpendicular to the receiving direction R when it is decomposed into the component R in the receiving direction of 72 and the component T which is perpendicular to it, the position where the sound received by the transducers 71 and 72 is generated. It only changes with wind speed.

On the other hand, receive direction R in the same direction of wind and the direction V ₂ serving as a headwind to the propagation direction R of the sound with respect to the direction V _2, for example, the transducer 72 serving as a headwind particular to the propagation direction of the sound
Then, the sound reaching the transducer 72 is extremely lowered.

In this embodiment, transducers are provided on both sides of the taxiway 6.
Since 71 and 72 are arranged, one transducer 71
On the other hand, in the case of a headwind, it becomes a tailwind for the other transducer 72, and it is possible to prevent an extreme decrease in the reception level due to the wind direction.

Although the two transducers 71 and 72 having different sensitivity frequencies are used here, it is obvious that a larger number of transducers may be used and the detection outputs thereof may be ORed.

As described above, the aircraft detector according to the present invention is provided with a plurality of sound-electric conversion transducers having sensitivity in a high frequency region and different sensitivity frequencies in the vicinity of the ground taxiway of the aircraft. The detection output is the logical sum of the high-frequency detection outputs of each of the above.Therefore, in the taxiway without being affected by the noise of other aircraft passing through taxiways other than the taxiway or the aircraft taking off and landing, It is possible to provide an aircraft detector capable of surely detecting the approach of an aircraft.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an aircraft detector according to the present invention, and FIGS. 2 to 4 are diagrams showing a distance from an aircraft to a transducer and a frequency spectrum of noise received by the transducer at that time, and FIG. Is a diagram for explaining the influence of the wind direction on the reception of the transducer, FIG. 6 is a diagram showing the configuration of an aircraft detector using an audio frequency sound level meter,
FIG. 7 shows noise data when a transducer is placed on the runway A at Haneda Airport and the approach of a Boeing 747 passing through the runway A is detected. 5 ... Aircraft, 6 ... Taxiway 71, 72 ... Transducer 81, 82 ... Amplification circuit 91, 92 ... Detection circuit 10 ... Logical sum circuit

Claims (2)

[Claims] 1. A plurality of sound-electric conversion transducers having sensitivity in a high frequency region and different sensitivity frequencies are provided in the vicinity of a ground taxiway of an aircraft, and a logical sum of high frequency detection outputs of the transducers is used as a detection output. An aircraft detector characterized in that 2. The aircraft detector according to claim 1, wherein the transducers are arranged on both sides of the taxiway.