JPS5972074A - Measuring device of underwater position - Google Patents

Abstract

PURPOSE:To measure a position with a high precision even if various reflected echoes exist, by eliminating the signal of a part having a disturbed phase by a phase difference gate control circuit. CONSTITUTION:Receiving signals are received by receiving elements 16-18 and are amplified in preamplifiers 19-21 and are converted to pulses by pulse circuits 22-24. A direct distance measuring circuit 25 counts the period from the transmission reference of a sounding body to the reception time with clocks corresponding to the underwater acoustic velocity to attain the distance. A phase difference gate control circuit 29 generates a gate part of a time corresponding to the number of mountains in a part, where the waveform is not disturbed, set by a mountain number set counter 30 as shown in Fig. (c). The period from a time D to a time E in Fig. (c) is a gate used for measurement, and the succeeding part is eliminated by the counter 30 because the phase is distrubed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position measuring device that uses underwater ultrasound to three-dimensionally measure the relative position of an underwater target with respect to a mother ship on the sea or in the sea.

Conventionally, this type of position measuring device, as shown in FIG. A receiver 2 consisting of receiving elements receives the sound waves from the sounding body 4, and detects the phase difference of the sound waves from the sounding body 4 input to each receiving element to detect the direction of the target object 3. With,
The position of the target object is measured three-dimensionally by measuring the arrival time of the sound waves between the sound generator 4 and the receiver 2 to determine the direct distance.

The measurement of the position of this target object will be explained.

First, as shown in FIG. 2, the receiver 2 installed on the mother ship 1
Four receiving elements 11 to 14 are arranged, and the spacing between these elements is between elements 11.14, 12.13, and 11.12.
The distance between question and 13.14 is the distance. In addition, the position of the sounding body 4 mounted on the target object 3 is set to point P (X, Y, Z), as shown in FIG. Ll, L2. L3. Let it be L4. Let the angle between PO and the Y-axis be 02+the angle between PO and the Y-axis be θ. It's a waste. Assuming that the distance between the receivers is less than half the wavelength of the ultrasonic frequency used, and the direct distance between the mother ship 1 and the target 3"! is sufficiently large compared to the distance between the receivers, each received wave It is assumed that the sound waves enter the element in equilibrium, and the following equation holds.

L2-L1=Dcosθ2 L2-L3=Dcosθ! In these equations, since the interval is known, L2-L
By measuring l and L2-L3 as the phase difference of each channel? ), cos θ, , cos θ, are determined, and the direction θ1 . θ2 is found.

On the other hand, the direct distance can also be determined by measuring the time from the transmission reference time to the reception time and taking into account the underwater sound speed.

Therefore, the position (x, y, z) of the target object is determined by the following equation.

X=L-cos θ1 Y=L-cos θ2 This position measuring device needs to accurately measure the phase difference between the signals received by each of the wave receiving elements 11 to 14. Therefore, if a phase disturbance occurs when the sound wave emitted from the sound generating body 4 is received by the wave receiver 2, the phase difference between each wave receiving element from the sound generating body 4 to the wave receiving element An error occurs in
It becomes difficult to detect accurate orientation.

In addition, before the sound wave enters the receiver 2, as shown in Fig. 1(b), in addition to the direct wave 5, a propagation path is generated for a ship bottom reflected wave 6 and a sea bottom reflected wave 7, and these six waves The combined signal is received by the wave receiving element. These received waves are shown in Fig. 4(a)~
(shown in dJ. This direct wave 5 (Fig. 4(a)), !
:, reflected waves 6 and 7 (Fig. 4(b), (C)) are combined to form a composite wave shown in Fig. 4(d). When this combined wave reaches the receiving element 1, if there is a sufficient time difference, it is possible to separate them using a time gate, etc. However, the reflected wave 6 from the bottom of the ship depends on the transmission pulse width and the rise characteristics of the receiving element. It also depends on the direct wave 5, but if it is difficult to separate it from the direct wave 5, and if the sounding body 4 is close to a reflective object such as the seabed, the influence of the seabed reflected wave 7 on the direct wave 5 can also be ignored. I feel empowered. This composite wave, as shown in Figure 4 (dl),
The part is only the direct wave 5, but the B and C parts are the reflected waves 6.
This is the part where phase disturbance occurs due to the overlap of 7.

Conventional position measuring devices are equipped with a time gate or a receiver at the tip of the lifting device to eliminate these effects, but it is necessary to sufficiently eliminate the effects of reflected waves that overlap with direct waves. This caused errors in direction.

An object of the present invention is to provide an underwater position measuring device that can reduce the azimuth error and improve the measurement accuracy by eliminating the shadow caused by the reflected waves. three or more wave receiving elements that receive signals sent from a sounding body of an object; a pulsing circuit that amplifies each signal received by each of the wave receiving elements and converts each signal into a pulse signal; an underwater position including a phase difference detection circuit that detects a phase difference between each of the converted signals, and a distance measurement circuit that measures a direct distance from the time from the time of transmission of the sounding body to the reception of the wave by each of the reception elements. In the measuring device, a gate control circuit outputs from the output of the distance measuring circuit a gate having a wave number selected such that the signal is at a predetermined reception level or higher and has no phase disturbance, and the pulsed signal is controlled by the output gate of the gate control circuit. and a gate circuit that selects each of the two.

In the present invention, the rising edge portion of the received signal is detected in order to remove from the measurement the portion of the signal received by each receiving element in which the phase is disturbed due to waves reflected from the ocean floor or waves reflected from the bottom of the ship. , the signal from this detection point to the number of pulse peaks set by the peak number setting counter is detected, and the direction of the target is calculated from the phase difference information of each received signal within this detection range. Direction measurement accuracy can be improved.

−〇− Next, the present invention will be explained in detail with reference to the drawings.

Figure 5 (block diagram of an embodiment of Fushiki's invention), Figure 6 (al
~(C1 is the operating waveform diagram in FIG. 5. In the figure, 1
6 to 18 are three wave receiving elements, and each wave receiving element receives a reception signal as shown in FIG. 6 (81).

Here, since position measurement can be performed with at least three wave receiving elements, a case with three wave receiving elements will be explained. These received signals are amplified by preamplifiers 19 to 21, and then pulsed by a pulse generator 2.
Pulsed at 2-24. The situation is as shown in FIG. 6(b). Numerals 26-28 are inter-channel phase difference detection circuits and 25Fi direct distance measurement circuits, which count and calculate the time from the transmission reference of the sounding body 4 to the time of reception using a clock corresponding to the underwater reference speed of sound. The gate control circuit 29 is a part that creates a gate width corresponding to a time period corresponding to a waveform waveform failure set by the waveform number setting counter 30, and its state is shown in FIG. 6(C).

FIG. 6 shows that the gate between C1 and E is the gate used for measurement with this device, and the lower part is excluded by the peak number setting counter 30 because the phase is disordered.

That is, a gate (FIG. 6(C)) is created from the point at which the direct distance measurement circuit 25 detects a received wave of a predetermined threshold level or higher to the count point E where the number of peaks is set. Note that the number of peaks may be one or more and about 40. The number of peaks required to eliminate this phase disturbance will vary depending on the equipment condition of the receiver, so it should be determined by observing the waveform during initial settings, but once set, no adjustment is necessary. .

Further, when the transmission frequency is constant, the number of peaks can be automatically set by detecting the regularity of the phase. 3
Reference numerals 1 to 33 are gates for controlling the phase difference detection signal to output only the signal during which the phase between E and E is not disturbed, as shown in FIG. 6 (C1). This is an arithmetic circuit that calculates the formula, this arithmetic circuit 3
4, the position of the target object is calculated and displayed on the display 35. When displayed on this display 35, horizontal distance and azimuth are converted into the necessary final data.

The angle of depression, etc. can also be calculated using (x, y, z) data.

As explained above, the present invention allows the phase difference gate control circuit to remove the signal of the part where the multi-phase is disturbed, so that position measurement can be performed with high accuracy even when there are seabed reflection echoes, ship bottom reflection echoes, etc. It will be done. Furthermore, since the present invention is provided with a counter for setting the number of peaks, it is possible to average the phase differences by the set number of peaks, thereby improving the direction detection accuracy.

In this example, the peak number setting counter was explained as being manually set, but when using a single frequency pulse for transmission, the length of the received wave (peak) can be automatically detected from the regularity of the phase of the received wave. You can also set the number of ridges automatically.

[Brief explanation of the drawing]

Figures 1 (al and b) are configuration diagrams showing the relationship between the sounding body installed on the target and the wave receiver installed on the mother ship, and the sound wave path incident on the receiver, and Figure 2 shows the relationship between the sounding body installed on the target and the wave receiver installed on the mother ship. FIG. 3 is a coordinate diagram showing the relationship with the receiver, FIG. 3 is a coordinate diagram showing the relationship between the target object and the mother ship, FIGS. The figure is a block diagram showing one embodiment of the present invention, and FIGS. 6A to 6C are waveform diagrams in the embodiment of FIG. ...Receiver, 3...
...Target, 4...Sounding body, 5...
Direct wave, 6, 7...Reflected wave, 11-14, 1
．． 6-18... Receiving element, 19-21...
...Preamplifier, 22-24...Pulsing circuit, 25-28...Phase difference detection circuit, 29...
...Gate control circuit, 3o...Tap number setting counter, 31-33...Gate, 34.
... Arithmetic circuit, 35. Old... Display. 10- (fA) (6,)'. :: 1-N+++ to mother-in-law ('q
, .

Claims (1)

[Claims] three or more wave receiving elements that receive signals sent from a sounding body of an underwater target, a pulsing circuit that amplifies each signal received by each of these wave receiving elements and converts them into pulse signals, and pulsing these signals. underwater position measurement comprising: a phase difference detection circuit that detects a phase difference between each signal; and a distance measurement circuit that measures a direct distance from the time from the time of transmission of the sounding body to the time of reception of the wave by each of the reception elements. In the apparatus, a gate control circuit outputs a gate of a wave number selected such that the signal is at a predetermined reception level or higher and has no phase shift from the output of the distance measuring circuit, and the pulsed signal is controlled by the output gate of the gate control circuit. An underwater position measuring device characterized by having a gate circuit that selects each of the following.