JPS644634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to an ultrasonic homing device that navigates underwater and tracks a target.

Although the present invention can be applied to flying objects as well as underwater vehicles using the same principle, the description will be given below using an underwater vehicle as an example.

This type of homing device includes active sonar devices and passive sonar devices. Conventionally, active sonar devices are equipped with a transmitter and receiver, or a transducer for both transmitting and receiving, on an underwater vehicle, and after the transmitter transmits pulsed sound, it is reflected from the target. The direction of the target can be detected by scanning the transmitted angular range using a receiver with a narrow-angle beam, or by preparing multiple narrow-angle beams in each direction. , determine the direction to steer. Alternatively, two receivers were installed at regular intervals, and the output waveforms of the respective oscillators were compared to determine the phase difference to determine the steering direction.

Passive sonar devices determine the direction of a target by receiving sound waves emitted by the target, and the method for detecting the direction is basically the same principle as that of active sonar devices.

Therefore, in order to improve the precision of orientation detection, the narrow-angle beam scanning method requires a sharper beam and a sufficiently large radiation surface relative to the wavelength. However, the homing device has dimensional limitations, and when using low-frequency waves with long wavelengths, the beam becomes wide-angle, making it unavoidable that the accuracy of azimuth detection is extremely reduced. On the other hand, in the phase difference detection method, the distance between the two receivers needs to be larger than the wavelength. However, if the interval is 1/2 wavelength or more, there is a problem that the same phase occurs in two or more directions within a range of 180 degrees forward, making it difficult to judge the true direction. There was a limit in principle. shape of the device,
Naturally, there was a problem in that if the spacing was narrower than 1/2 wavelength due to size limitations, no improvement in accuracy could be expected.

By measuring the number of waves received while cruising, the present invention provides an effect equivalent to that of being equipped with a very sharp receiver with a large radiation surface, and accurately detects waves even at low frequencies. To provide a homing device that can efficiently track a target.

That is, the present invention arranges at least two receivers for one set of rudders in a plane perpendicular to the rudder and parallel to the axis, and measures the wave number of the output signal of each receiver, This is a homing device that tracks a target by steering in a direction where the difference in wave numbers is zero.

Next, embodiments of the present invention will be described with reference to the drawings. 1 showing a plan view and a simplified A-A' cross-sectional view of a first embodiment of a mobile vehicle embodying the present invention;
Referring to Figures a and b, there is a vehicle 1 and four receivers 2-1, 2-2, 2-3,
2-4 and the wave numbers of the output signals from each receiver are measured and compared, and the vertical and horizontal rudders 4-1, 4-2, 4-3,
Wave number measurement comparison circuit 3 that transmits the steering signal to 4-4
including.

Next, the principle of the present invention will be explained with reference to FIG. 0 in FIG. 2 indicates the target, which is the origin of the X and Y axes. p indicates the sound pressure of a sound wave emitted from the target 0 or a sound wave reflected from the target at a certain frequency. Since the vehicle is located far from 0, p is regarded as a spherical wave. The _solid circular arc lines, .

Now, the position of the vehicle 1 at time t ₁ is P ₁ (t ₁ )
Let us consider the case where the vehicle moves in the direction of arrow 5. Assume that the vehicle P ₂ (t ₂ ) is reached at time t ₂ . Since the sound wave propagates over a certain distance in the time t ₂ - _{t 1} , the distribution of p also changes, but to simplify the explanation of the principle, if we fix the distribution at t ₁ for a while, the received During this period, wave device 2-1 (P ₁ ) is ′,
It can be seen that ,′,, ,′, have been crossed. On the other hand, the receiver 2-3 (P ₁ ) is ′,,′,
I know that I have crossed the Therefore, when the received wave output for the maximum and minimum sound pressure values is read by the wave number measurement and comparison circuit 3, the output of the receiver 2-1 is 6, and the output of the receiver 2-3 is 5. become individual. Then, it is detected that a difference of one wave number has occurred between the two wave receivers, and a steering signal is sent to the rudders 4-2 and 4-4 to rotate the mobile vehicle 1 to the right (in the direction of 0). Then time t ₃
If we consider the period from t ₃ to t ₄ in the same way, assuming that the position of P ₃ (t ₃ ) is in
Since there are 5 outputs for 3, it can be seen that at P ₄ (t ₄ ), the vehicle is still rotated to the right. In this way, it asymptotically approaches target 0 while rotating clockwise.

The above assumes that there is no propagation of sound waves (that is, time
t ₁ ) and the target was also fixed, but even if the propagation of the sound wave and the movement of the target occur, the above operating principle will not be affected, as only the frequency of the sound wave received by the Doppler result will change. I understand. Furthermore, while the target is on the right side of the vehicle, if it is on the left side, the magnitude of the output value is reversed to the right and left, so the steering is also reversed and asymptotic in a counterclockwise direction. Therefore, it can be seen that tracking is performed with less waste.

Although Fig. 2 is explained using the XY plane, the same principle can be applied to the XZ plane, etc., by installing three or more receivers considering the Z axis perpendicular to this, and selecting an appropriate combination of receivers to compare. It is made up of. That is, receivers 2-2 and 2-
By performing similar operations in parallel using 4, spatially efficient tracking can be achieved.

A second embodiment is shown in FIG. 3 as an application example for a similar purpose. In FIG. 3, a is a side view of the vehicle, and b is a sectional view taken along line C-C'. Three receivers 6-1, 6-
Vertical rudders 4-1, 4 using the output signals of 2, 6-3
This is a homing device that performs spatial tracking similarly to the second embodiment by operating the horizontal rudders 4-2 and 4-4. Here, 7-1, 7-2, and 7-3 are output terminals of each receiver.

Next, the principle will be explained. Receiver 6-1 and 6-
The line connecting the vertical rudders 4-1 and 4-3 is located in a plane perpendicular to the plane containing the vertical rudders 4-1 and 4-3 and parallel to the axis. The line connecting the receivers 6-2 and 6-3 is the horizontal rudder 4-2 and 4.
-4 in a plane perpendicular to the plane containing the axis and parallel to the axis. By arranging the receivers in this way, the difference in wave numbers between the outputs of 7-1 and 7-2 is detected and the vertical rudders 4-1 and 4-3 are operated.
The same objective as described above can be achieved by detecting the wave number difference between the -3 outputs and operating the horizontal rudder.

By the way, when comparing the advantages and disadvantages of the first embodiment and the second embodiment, the former has a wider spacing between the receivers, so it has a shorter travel distance to read the difference in the wave number, and has better sensitivity. It turns out. In the latter case, the spacing between the receivers becomes a little narrower, so the sensitivity deteriorates accordingly, but one less receiver is needed.

The above explanation was based on the case of vertical rudders and horizontal rudders installed at 90-degree intervals, but as a more advanced application example, we could use a moving vehicle with multiple rudders installed at 45-degree or 30-degree intervals. A homing device can be considered that tracks a target over the shortest distance by making similar homing by placing two or more receivers in a plane perpendicular to each rudder and parallel to the axis.

Note that if it takes a long time to travel until a difference in wave number occurs, the movement of the vehicle may become a series of long broken lines, resulting in wasted tracking time. In such cases, use multiple wave number measurement comparison circuits,
By delaying the start point of measurement little by little and operating them in parallel, and switching and connecting the steering signal circuits in synchronization with their respective outputs, it is possible to move in a series of short broken lines.

Although the explanation has been made for the case where the wave number is read every 1/2 wavelength, it is also possible to read the wave number every 1 wavelength. However, in this case, it takes a little longer to detect the difference.

As described above, according to the present invention, when the direction of the steering body matches the propagation direction of the sound wave and is directed toward the target, there is no difference in wave number, so the steering vehicle moves straight toward the target. However, if you start steering from completely the opposite direction, you will end up going straight ahead without changing direction, which is inconvenient. Such a chance is extremely rare and poses almost no practical problem, but in order to obtain the steering signal as quickly as possible, the rudder may be set so that the first movement of the rudder vehicle is a slight rotation.

In addition, although the explanation has been given on the case where each of the above-mentioned receivers is one, it is also possible to use four receivers as shown in the third embodiment whose side view and simplified cross-sectional view are shown in FIGS. 4a and 4b. Wave device 2-1-1, 2-1-2, 2-1-3, 2
-1-4, 2-2-1, 2-2-2, 2-2-
3, 2-2-4..., and connect it electrically to 1.
The same principle holds true if you connect a set of blocks.
However, in this case, the position of each set of receivers may be considered in terms of the geometric center position of the radiation surface.

As explained above, the present invention measures the wave number, determines the direction of the target, and steers it, thereby making it possible to asymptotically track even low-frequency sound waves with almost no steering. In particular, since the receiver can be attached to the fuselage, the space of the steering body can be fully utilized and a high-performance homing device can be obtained.

[Brief explanation of drawings]

1A and 1B are a side view and a sectional view taken along line A-A' of the first embodiment of the present invention, and FIG. 2 is a diagram illustrating the principle of the present invention.
Figures 3a and b are a side view and a sectional view taken along line C-C' of the second embodiment of the present invention, and Figures 4a and b are the third embodiment of the present invention.
FIG. 2 is a side view and a sectional view taken along line B-B' of the embodiment. 1... Rudder running body, 2-1, 2-2, 2-3, 2-
4,2-1-1,2-1-2,2-1-3,2-
1-4, 2-2-1, 2-2-2, 2-2-3,
2-2-4, 6-1, 6-2, 6-3...Receiver, 3...Wave number measurement comparison circuit, 4-1, 4-2,
4-3, 4-4... Rudder.

Claims (1)

[Claims] 1 A set of rudders provided on a vehicle or a flying vehicle, at least two receivers arranged in a plane perpendicular to the rudder and parallel to the axis of the vehicle or flying vehicle; A wave number measuring means for measuring the number of peaks and troughs of the output voltage corresponding to the received signal from the target obtained by the wave receiver as a wave number, and corresponding to the two wave receivers combined in the steering direction. A homing device comprising: a comparing means for comparing wave numbers obtained by the wave number measuring means; and a steering means for steering the rudder in a direction in which the comparison difference becomes zero based on the output of the comparing means.