JPS58111773A - Homing apparatus - Google Patents

Abstract

PURPOSE:To enable the homing of a target accurately and efficiently by steering a travelling body counting the number of waves which are received in continuous wave transmitting and receiving operations during the travelling. CONSTITUTION:A wave transmitter S arranged on the axis or in the perimeter thereof of a travelling body 1 and transmits waves continuously. Groups of receivers 2-1-1 and 2-1-2-2-4-1 and 2-4-2 are arranged on the axis of the body to receive reflected waves. The groups of the receivers are arranged at an interval D equivalent to an odd integral factor of 1/2 wavelength of respective transmitted signals and connected in sum together. The number of waves of output signals from the groups of receivers is measured and compared with a circuit 3 for measuring and comparing the number of waves and vertical and horizontal rudders 4-1-4-4 are operated in such a direction that the difference between measured values becomes zero. This is equivalent to installation of a very sharp receiver with a large radiant surface thereby enabling the homing of a target accurately and efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to an active sonar homing device that navigates underwater and tracks targets.

Conventionally, active sonar devices have equipped an underwater vehicle with a transmitter and a receiver (acoustic signal receiving sensor) or a transducer for both transmitting and receiving, and the transmitter transmits pulsed sound. After that, the echoes reflected from the target can be received by scanning the angular range of the transmitted wave using a receiver with narrow-angle beams, or by preparing a large number of narrow-angle beams in each direction in advance. Detects the direction of the target and determines the direction to steer. Alternatively, two receivers were installed at a fixed interval, and the output waveforms of the respective oscillators were compared to determine the "C phase difference" to determine the steering direction.

Therefore, in order to improve the accuracy of direction detection, the narrow 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, which inevitably reduces the accuracy of azimuth detection.

On the other hand, in the phase difference detection method, it is necessary to increase the distance between the two receivers relative to one wavelength. However, if the distance is longer than the wavelength, there is a problem in which 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.

If the spacing is narrower than one wavelength due to limitations in the shape and dimensions of the device, there is the problem that no improvement in accuracy can be expected. Furthermore, in the conventional active sonar type, pulse-modulated sound waves are transmitted and reception is performed using the pause time of the wave transmission. For this reason, the time spent transmitting waves was wasted as it was not possible to obtain information from the target.

In addition to this, if no echo is obtained with the first wave transmission, it means that until the reception time of this wave, information on whether or not to steer is not obtained, so waiting for the second wave transmission is a waste. There was a big drawback that it became.

The present invention continuously transmits and receives waves while cruising, and when the wave number of the received waves is measured, the result is 1, which is equivalent to having a very sharp receiver with a large radiation surface. The present invention provides a homing device that is highly accurate and time efficient even at low frequencies.

That is, the present invention continuously transmits ζ waves from transmitters arranged on or around the axis, and connects the receivers parallel to the axis at intervals of an odd integer multiple of one wavelength of the transmitted signal. A plurality of wave transmitter groups are arranged at intervals in a direction that has a directional component other than the traveling direction of the vehicle, and echoes are continuously received while the vehicle is traveling. This homing device measures the wave number of the output signal of each receiver group and tracks the target by steering the wave number difference in the direction of zero.

Next, embodiments of the present invention will be described with reference to the drawings.

A plan view of the first embodiment of the vehicle implementing the present invention, A-
Figures 1 (a) and (b) show the A' arrow diagram and the received wave directivity.
), (C), and (d), a mobile vehicle 1 and a first receiver group 2-1- installed at intervals d in the axial direction of this fuselage.
1, 2-1-2 and second receiver group 2-2-1.2-21
, and similar third and fourth receiver groups 2-3-1.2-
3-2.2-4-1.2-4-2 and the wave numbers of the output kaiber from each receiver were measured and compared, and the vertical and horizontal rudder 4-1.4
-2.4-3.4-4 includes a wave number measurement and comparison circuit 3 that transmits a steering signal and a wave transmitter S attached to the tip on the axis of the fuselage. 2-1.2-3 indicates the center position of the first and second receiver groups.

Next, the present invention will be explained in detail.
The spacing between the receivers corresponds to seven wavelengths of the sound wave transmitted from the transmitter S. First receiver group 2-1-1 and 2
-1-2 are electrically sum-connected, so if the output voltage obtained from this receiver group is E(θ), then 2-1 and 2-3 are connected as shown in Figure 1(C). On the Y' axis passing through E(9
0 degree) indicates the maximum value, and the x'-x" axis perpendicular to it (
E (Q degrees) on the vehicle axis) exhibits directivity of zero. The same applies to other receiver groups. However, θ is x
It is the azimuth angle based on the X' force direction of the '-x' axis.In other words, the sound waves transmitted from the transmitter S are diffused throughout the space, but
Sound waves that reach the two receivers directly do not appear as output. However, echoes arriving from a direction other than 0 degrees will appear as an output voltage.

Next, the principle of the method of steering using this output will be explained with reference to Fig. 5-2. 0 in FIG. 2 indicates the target, which is assumed to be at the origin of the X and Y axes. Zl p indicates the distribution of the minimum value of the sound wave emitted from the target O or the sound wave ■' reflected from the target at a certain frequency.

Now, the position of the vehicle 1 at time t1 is Pl(tl)
Let us consider the case where the vehicle moves in the direction of arrow 5. Time t2
Suppose that the vehicle reaches Pg (t2) at . Since the sound wave propagates over a certain distance in a time of 12-11, the distribution of b also changes, but to simplify the explanation of the principle, if we fix the distribution at t for a while, we can see that the receiver It can be seen that 2-1 (P□) crossed 0', o, o, o, o, o during this time. On the other hand, it can be seen that the receiver 2-3 (Pl) crossed @, ■, [phase], [phase], and 0. 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 61 output of the receiver 2-1 is 6, and the output of the receiver 2-3 is 5. becomes.

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 rudder 4-2, 4-4 to rotate the vehicle 1 to the right (direction O).

Next, assuming that the position is Ps(ta) at time t3, t3
Considering the period from to t4 in the same way, the output of 2-1 is 6
Since the output of 2-3 is 5, it can be seen that the vehicle is still rotated to the right at P4 (t4). In this way, it asymptotically approaches target 0 while rotating clockwise.

The above is based on the assumption that there is no sound wave propagation (that is, fixed at time t It can be seen that simply changing the frequency does not affect the above operating principle. In addition, although the target is on the right side of the vehicle, if it is on the left side, the magnitude of the output value is also reversed between right and left, so the steering is also reversed and becomes counterclockwise ÷ asymptotic. Therefore, it can be seen that tracking is performed with less waste.

Although Fig. 2 was explained using the XY plane, the same principle can be applied to the XZ plane, etc., if three or more receivers are installed considering the Z axis perpendicular to this, and the combination of receivers to be compared is selected appropriately. It will be established. That is, by performing similar operations in parallel using the receivers 2-2 and 2-4, spatially efficient tracking can be achieved.

In addition, if it takes a long time to travel before a difference in wave number occurs, the movement of the vehicle may be forced by each long broken line, resulting in wasted tracking time. In such cases, multiple wave number measurement and comparison circuits are used, the start points of the measurements are delayed little by little, they are operated in parallel, and the steering signal circuits are switched and connected in synchronization with the respective outputs, thereby making it possible to measure short broken lines. You can exercise by connecting.

Although the wave number reading is performed for every 1/2 wavelength in the explanation, it may be read for 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 vehicle matches the propagation direction of the sound wave and the direction is in the direction of the willow, it is difficult to cause a difference in wave number, so the vehicle moves straight toward the target. In addition,
Even when the output becomes completely O due to the directivity of the receiver group, the wave number measurement and comparison circuit does not operate, so the vehicle moves straight without steering. However, if you start your front run completely in the opposite direction, you will end up running straight in the opposite direction without changing direction, which is inconvenient. Such opportunities are extremely rare and pose little practical problem, but in order to obtain the steering signal as quickly as possible, it is best to set the rudder so that the turning action of the vehicle is a slight rotation. . The receiver spacing is E (0 degree) even when the receiver spacing is 1/2 wavelength or an odd integer multiple of 1/2 wavelength.
is zero, so it is possible to transmit and receive waves continuously. FIG. 1(d) shows the directivity in the case of 3.5 wavelengths. Compared to FIG. 1(c), the range of poor sensitivity when θ is around 0 degrees is narrower, which is advantageous because sensitive steering can be performed even when the direction of the vehicle approaches the target direction. However, there are places where E(θ) becomes zero even in locations other than the 0 degree azimuth, which brings about a disadvantage, but when the vehicle is running forward at high speed, it is more advantageous because it escapes from this dead zone in a short time due to inertia. It is better to select the value of D according to the forward running speed, etc. Furthermore, the number of receivers in the receiver group does not necessarily have to be two. For example, even if an even number of beams are used and D is divided into a plurality of 1/2-wavelength beams and they are arranged in the axial direction, E (o degrees) becomes zero, so the same effect can be obtained.

The transmitted sound directly reaching the can receiver group is in phase.

Therefore, the sensitivity of the receiver is 2 when the value of 2-1-2 is 1.
When the values of -1-1 and 2-1-3 are made 1/2 and the sum is connected, E (Q degree) becomes zero.

As explained above, the present invention utilizes a system that measures wave numbers to determine the direction of a target and steers the target, and by continuously transmitting and receiving waves, it is possible to accurately and time-efficiently respond to low-frequency sound waves. This has the effect of providing a high performance homing device.

[Brief explanation of the drawing]

FIGS. 1(a), (b), (c), and (d) are a plan view of the first embodiment of the present invention, a view along arrow A-A', and a diagram showing directivity, and FIG. 10-2. are explanatory diagrams of the principles of the present invention, Figure 3 fa), (b)
, (c) is a plan view showing the second embodiment of the present invention, B-
They are a B' arrow view and a c-c' side view. 1...... Navigation vehicle, 2-1-1, 2-1-2.
2-1-3.2-2-1.2-2-2.2-2-3...
...Receiver, 3...Wave number measurement comparison circuit, 4
-1.4-2, 4-3, 4-4... Rudder. 11- Mine 1 Bibi

Claims (1)

[Claims] Transmitters are arranged on or around the axis of the vehicle, and a plurality of receiver groups are arranged parallel to the axis at intervals of an odd integer multiple of 100 wavelengths of the transmitted signal and are connected together. wave number measuring means arranged at intervals in a direction having a direction component other than the axial direction, and measuring the wave number of each output signal of the receiver group; and two predetermined wave receiver groups. Homing characterized by comprising a comparison means for comparing wave numbers obtained by wave number measurement means corresponding to the above, and a steering means for operating a rudder in a direction in which the comparison difference becomes zero based on the output of the comparison means. Device.