JPS63256881A - Transmitter and receiver of acoustic position measuring instrument - Google Patents

Abstract

PURPOSE:To improve position measurement accuracy by measuring the constant level and peak level of a received ultrasonic wave and the necessary times of propagation to their detection points from the transmission of the ultrasonic wave. CONSTITUTION:A transmitter 1 sets FFs 14-16 and counters 20-22 and 38 begin to count a clock from an oscillator 23, so that a transmitter sends out an ultrasonic save. Transponders 3-5 send out ultrasonic waves of different frequency in response to said ultrasonic wave and the constant level and peak level of the received ultrasonic level are detected by constant level detectors 26-28 which cause a little misdetection and high-accuracy peak level detectors 27-29 through a receiver 6, a receiver 7, and filters 8-10 to controls the counting stop of the counters 20-28 and the writing of the counted value of the counter 28 to memories 39-41. Then the constant level and peak level, and the times of ultrasonic propagation to the respective detection points are measured and switched and outputted through a switch 43, an arithmetic circuit 42 makes corrections according to the delay times of the detectors 26-28 and 29-31, and the position measurement accuracy is improved by two kinds of level detection.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an acoustic positioning device.

(Prior Art) A conventional device of this type is disclosed in Japanese Patent Application Laid-open No. 18777/1983. This method uses ultrasonic signals to measure the distance from three or more reference transponders installed on the seabed to determine the position of a delivery device mounted on a ship.

FIG. 2 is a block diagram showing an example of the configuration of a conventional acoustic positioning device.

In the figure, 1 is a transmitter, 2 is an ultrasonic wave transmitter, 3 and 4.5 are transponders, and in response to the ultrasonic signal transmitted from the wave transmitter 2, each unique frequency fL, f2.
Sends f3 ultrasonic signal. 6 is a receiver (usually installed in the same position as transmitter 2), 7 is a receiver, 8
, 9.10 are each frequency fl, f2 . A filter that extracts the sound wave signal of f3, 11, 12, and 13 are level detectors, 1
4.15.16 is a flip-flop, 17°18.19
is an AND gate, 20, 21.22 is a counter for time measurement, 23 is an oscillator that generates a clock signal for time measurement, 24
25 is an arithmetic circuit that calculates the distance between each transponder 3°4.5 and the receiver 6, and 25 is a display device.

Next, the operation of the acoustic positioning device shown in FIG. 2 will be explained.

An interrogation signal is transmitted from the transmitter 1, and at the same time, flip-flops 14, 15, and 16 are set.

This interrogation signal is transmitted by the transmitter 2 into the water as an ultrasonic signal. Transponders 3 and 4 installed underwater
．． 5 receives the interrogation signal, and in response, transmits frequencies fl, f2 . Each ultrasonic signal of f3 is sent out. These response signals are received by the receiver 6 and converted into electrical signals. Then, it is amplified to a constant level by the receiver 7, and filters 8, 9 and 10 filter the frequencies fl, f2, . It is identified by f3. The signal that has passed through the filter 8.9.10 is passed through the level detector 11.12.13, and when it reaches a certain level, a detection signal is output, and the flip-flop 1
4, 15, and 16 respectively. The flip-flops 14, 15.16i;! It is set when the interrogation signal is sent from the transmitter 1, is responded to by the transponders 3, 4.5, and is set only for the time when the response signal reaches the receiver 7 again. For this purpose, the output Q of the flip-flops 14, 15.16 is inputted to the AND gate 17, 18, 19 together with the clock signal of the oscillator 23, counted by the counters 20, 21, 22, and output from each transponder 3, 4.5. Data proportional to the distance to the transmitter 2 and receiver 6 is obtained.

These data are corrected by the arithmetic circuit 24 for the delay time until the response in the transponder 3.4.5, the delay time required for level detection, the speed of sound, etc. Each distance between the transponders 3, 4.5 is determined accurately. Based on this determined distance, the position of the receiver 6 is determined geometrically and displayed on the display 25, assuming that the position of the transponder 3.4.5 is known.

(Problem to be Solved by the Invention) However, in the device having the above configuration, in order to widen the measurement position range and improve the S/N ratio, the band of each filter 8, 9, 10 must be made as narrow as possible. However, if the band is narrowed, the rise of the waveform will become slower and the delay time for level detection will increase. Therefore, the accuracy of distance measurement decreases. That is, since the slope of the level is low, there is a problem that the delay time changes greatly due to a slight level change. In order to eliminate this, there is a method of simply using the detection point of the peak value instead of level detection, but there is a risk of erroneous measurements due to multiple reflections from the seabed, etc.

FIG. 3 is a waveform diagram of each sound wave signal for explaining the problems of the conventional acoustic positioning device. (a) shows the ideal received signal. This received signal is filtered by narrow band filters 8.9.
When 10 is passed through, a waveform like that shown in (b) is obtained. Here, level detectors 11, 12 and 13 are used to detect a certain level, for example E1.
If a constant level detector is used that outputs a detection signal when the level exceeds E1, the detection output will appear when the level E1 is exceeded, and the required propagation time T1 from the time of transmission can be obtained. In reality, if the delay time τ1 from the rising edge of the waveform to this level detection is corrected, an accurate propagation time can be obtained. however,
In this case, there is a problem that the required propagation time Tl changes greatly due to the level fluctuation of the signal shown in (b). (C
) shows the case of using a peak level detector which outputs a detection signal at the peak of the signal passed through filter 8.9.10, and similarly obtains the required propagation time T2.

The peak value Em is usually obtained by correcting the delay time τ2 determined by the characteristics of the filter 8.9.10 to obtain an accurate propagation time. (d) shows the received waveform of the receiver 7 when a plurality of reflected waves from the seabed etc. overlap. The received wave in (d) is a superposition of two signals, and the level increases when the peaks overlap due to the phase relationship, and decreases when the peaks and troughs overlap. Now this (d) signal is filtered by narrowband filter 8, 9.1
When it passes through 0, the waveform becomes as shown in (e). Here, if constant level detectors are used as the level detectors 11, 12, 13, the required propagation time T3 is obtained, and if a peak level detector is used, the required propagation time T4 is obtained. When using a constant level detector, there are fewer erroneous measurements, but the measurement accuracy is low.
Furthermore, when using a peak level detector, the measurement accuracy is good, but there are many erroneous measurements M1.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device with excellent positioning accuracy that can eliminate the above-mentioned problems such as a decrease in distance accuracy due to an increase in the delay time of level detection, and erroneous measurements due to multiple reflections. shall be.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has provided that each acoustic response device installed at a plurality of predetermined positions responds to a sound wave signal transmitted from a transmitting/receiving device to The transmitting/receiving device transmits a sound wave signal having the characteristics, identifies and receives each of the responded sound wave signals, and calculates the distance between each acoustic response device and the transmitting/receiving device from the sound speed and propagation time of each sound wave signal. The transmitting/receiving device of the acoustic positioning device that measures the position of the acoustic positioning device includes a constant level detector that detects when the received sound wave signal has reached a predetermined level or higher, and a constant level detector that detects when the received sound wave signal has reached a peak level. a peak level detector; a first measuring means for measuring the time required for propagation from the point of transmitting the sound wave signal to the point of time when the constant level detector detects the constant level; a second measuring means for measuring the time required for propagation to reach the peak level detection point of the detector; and correcting the required time for propagation by calculating the delay time of detection by each level detector for the measurement data of each of the measuring means. A correction means and a switching means for mutually switching between the first measurement means and the second measurement means for the correction means are provided.

(Function) According to the present invention, when the correction means is switched to the first measurement means side by the switching means, the measurement data by the first measurement means is corrected by the correction means for the delay time by the constant level detector. When the second measuring means is switched to the second measuring means side, the delay time caused by the peak level detector is corrected by the correcting means for the measurement data obtained by the second measuring means.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an acoustic positioning device as an embodiment of the present invention.

In this figure, the same parts as in FIG. 2 are designated by the same reference numerals, and the explanation thereof will be omitted as appropriate.

Each transponder 3, 4.5 constitutes an acoustic response device, and the other parts constitute a transmitting/receiving device.

26, 27, 28 are constant level detectors, which are basically the same as the constant level detectors explained as level detectors 11, 12, 13 in FIG. 2, and each filter 8, 9, .
Ten sound wave signals are sequentially sampled, and when the level reaches a predetermined level E1 shown in FIG. 3(b), a detection signal is output for each sampling.

Reference numeral 29.30.31 is a peak level detector, which is basically the same as the peak level detector explained as level detector 11.12.13 in Fig. 2, and the sampling is based on the level of the sound wave signal. As shown in FIG. 3 (C), a detection signal is output at each sampling while the signal increases to the peak value Em, and after the peak value Em is detected, the signal is output until the next peak value Em is exceeded. do not.

FIG. 4 is a block diagram of one set of circuits of constant level detectors 26, 27.28 and peak level detectors 29, 30.31, 32 is a detector, 33 is an A/D converter, 3
4 is a comparator, 35 is a setter, the comparator 34 and the setter 35
constitutes a constant level detector 26. 36 is a comparator, 37 is a memory, and the comparator 36 and the memory 37 form the peak level detector 29.

In FIG. 4, the output of the filter 8 is detected by a wave detector 32, and then sampled at regular intervals and converted into a digital value by an A/D converter 33. This value is compared in a comparator 34 with a level E1 preset in a setter 35, and when a value equal to or higher than this set level E1 is input to the comparator 34, a constant level detection signal is output.

On the other hand, the memory 37 is reset by receiving a reset signal at the time of transmission from the transmitter 1, stores the value of the A/D converter 33 every time it receives the following set signal, and stores the value of the A/D converter 33, and the comparator 3
6, the value of the A/D converter 33 and the value of the memory 37 are compared, and if the value of the A/D converter 33 is larger, a peak level detection signal is output, and at the same time a set signal is sent to the memory 37. The value of the A/D converter 33 at that time is stored. In the next step, when there is a new input to the A/D converter 33, it is compared with the value in this memory 37,
If the value of the A/D converter 33 is larger, a peak level detection signal is output, and a set signal is given to the memory 37. This operation continues until the contents of the memory 37 reach the maximum value, that is, the peak level detection signal is output every time there is an input larger than the previous maximum value.

The counters 20, 21.22 constitute the first counting means, and as explained in FIG.
The clock signal of the oscillator 23 is counted over the period up to the time when each constant level detection signal is outputted, and the time required for propagation is counted.

A counter 38 is reset each time an interrogation signal is sent from the transmitter 1, and counts the clock signal of the oscillator 23. Reference numerals 39, 40, and 41 denote memories that respectively store the count values of the counter 38 each time a peak level detection signal is output from the peak level detectors 29, 30, and 31, respectively. The counter 38 and memories 39, 40.41 are
Each peak level detector 29, 30° 31 acts as a second counting means and starts from the time when the interrogation signal is selected from the transmitter 1.
The time required for propagation until each peak level detection signal is output is counted.

42 is an arithmetic circuit equipped with a correction means, which calculates the distance between each transponder 3.4.5 and the receiver 6 to determine the position of the receiver 6, similar to the arithmetic circuit 24 in FIG. However, as a correction means, counters 20, 2
When a value of 1.22 is received, use the result obtained by calculating the delay time τl in advance from the rise characteristics of the signal of filter 8.9.10 as shown in Fig. 3(b). Then, correction is performed using the delay time τl. and memory 39
, 40.41, the filter 8,
From the rise characteristics of the signal in 9.10, (c) in Figure 3 is obtained.
Correction is performed using the delay time τ2 shown in FIG.

43 is a switch as a switching means, and usually each memory 39
, 40.41 are connected to the arithmetic circuit 42, positioning is performed by each peak level detector 29, 30.31, and if there are many erroneous measurements due to the situation of the seabed, etc., each counter 20,
21 and 22 side to switch to positioning using each constant level detector, for example, the arithmetic circuit 42
calculates the standard deviation of the data for each 11th place result, tests the reliability of the data, and switches between them.

(Effects of the Invention) As explained above, according to the present invention, it is possible to selectively use a peak level detector with relatively high detection accuracy and a constant level detector with relatively few false positives. , it becomes possible to perform positioning that takes advantage of the strengths of each detector depending on the state of the measurement environment such as the ocean floor.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an acoustic positioning device as an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional acoustic positioning device, and FIG. 3 shows the problems of the conventional acoustic positioning device. FIG. 4 is a waveform diagram of each sound wave signal to be described, and is a block diagram of the circuit of the constant level detector and peak level detector of FIG. 1. 1... Transmitter 2... Transmitter 3.4.5... Transponder (acoustic response device) 6.
・Receiver

Claims (1)

[Claims] Each of the acoustic response devices installed at a plurality of predetermined positions sends out a sound wave signal having a unique characteristic in response to the sound wave signal transmitted from the transmitting/receiving device, and the transmitting/receiving device responds to each of the responded sound waves. The received sound wave is transmitted to the transmitting/receiving device of the acoustic positioning device, which identifies and receives the signal, calculates the distance between each acoustic response device and the transmitting/receiving device from the sound speed and propagation time of each sound wave signal, and measures the position of the transmitting/receiving device. a constant level detector that detects when the signal reaches a predetermined level; a peak level detector that detects that the received sound wave signal has reached a peak level; and a peak level detector that detects when the received sound wave signal reaches a peak level; a first measurement means for measuring the time required for propagation to reach a point at which the level detector detects a constant level; and a first measuring means for measuring the time required for propagation to reach the point at which the peak level detector detects the peak level from the point at which the sound wave signal is transmitted. a second measuring means; a correcting means for correcting the required propagation time by calculating a detection delay time by each level detector for the measurement data of each of the measuring means; and a first measuring means for the correcting means. 1. A transmitting/receiving device for an acoustic positioning device, comprising a switching device for mutually switching between the first measurement device and the second measurement device.