JPS5925989B2 - How to measure moving speed and distance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of measuring the moving speed or moving distance of a moving object by fully utilizing ultrasonic waves and the like.

For example, when a capsule is lowered from a mother ship toward a signal source such as an ultrasound signal placed on the ocean floor, it would be possible to measure the speed or distance traveled by the capsule based on changes in the phase of the signals received by the capsule.

That is, by comparing the phases of the reference signal received at the reference point on the mother ship and the received signal received by the capsule at the current position, and detecting all changes in the phase difference, the above-mentioned moving speed or movement can be determined. Distances can be measured, but if the reference signal receiver is installed on the mother ship and the reference signal is constantly sent to the capsule, a long cable must be used to connect it to the capsule. .

The present invention is characterized by solving such problems and making it possible to perform phase comparison only on the capsule side by making it possible to reproduce the reference signal received by the capsule itself at the reference point in all the capsules. It is something to do.

Hereinafter, the method of the present invention will be explained in detail with reference to all the drawings.

In the present invention, as shown in FIG. 1, a signal source 1 such as an ultrasonic wave is installed on the seabed, and a capsule 3 is
The entire capsule 3 is lowered toward the signal source 1, and in this case, the capsule 3 is equipped with a receiver 4 for receiving the signal from the signal source 1 and a signal processing device 5.

This signal processing device 5 includes a reference signal reproduction circuit that reproduces the reference signal sampled by the capsule itself at the reference point before the start of descent with a constant delay time, and a reference signal reproduction circuit that reproduces the reference signal sampled by the capsule itself at the reference point before the start of descent, and the reproduced reference signal and the received signal at the current position. As shown in FIG. 2, the reference signal reproduction circuit includes n delay elements d1. d2. ..., dn
``!lrDelay circuit connected in series and each delay element d1
, d2 +..., a clock for setting the delay time Δt2 in do, and each delay element d1td2*...,
It is equipped with a multiplexer for extracting the output from dn as one output signal by time division, and the number n of delay elements, delay times Δt, and ff1nXΔ are set to be the total measurement time.

Therefore, when moving the capsule 3 mentioned above, first,
At the reference point, the receiver 4 receives the signal from the signal source 1, thereby sampling the reference signal shown in FIG. 3a.

When the sampled reference signal is input to the delay circuit, this reference signal is transmitted to each delay element d, connected in series.
9 d21...

dll, a delay of Δt is applied to each of them, and
11 b! ..., are outputted from each element with a time delay of 6x by Δt, as shown by bn.

Therefore, by sequentially switching the delayed outputs from each of these elements by a multiplexer every Δ and taking it out as one output signal, a reference signal sequence in which the reference signal is repeated at a time interval of Δt, as shown in FIG. is obtained.

On the other hand, the capsule 3 starts to descend at the 0 point (FIG. 3) where the sampling of the reference signal ends and the reference signal is output from the first stage delay element d1. The received signal received by (Fig. 3 d)
and the reproduced reference signal are sent to the phase comparator circuit,
The moving speed of the capsule is measured by detecting a change in the phase difference between both signals, and the moving distance of the capsule is measured by cumulatively detecting the change in the phase difference.

When time Δt has elapsed from the start of measurement, a new reference signal is output from the second stage delay element d2, and the reference signals are reproduced one after another at time intervals of Δt in the same manner, and these reference signals and the received signal are A phase comparison is performed between them to measure the moving speed or the total distance traveled by the moving object.

FIG. 4 shows all different embodiments of the reference signal reproduction circuit. In this embodiment, n delay elements d11 d2,...
, dn constitutes a delay circuit such that n×Δt−total measurement time.

When measuring the moving speed or moving distance, the reference signal '(rnΔt) shown in FIG. 5a is sampled at the reference point, and the reference signal shown in FIG. At the same time as the capsule starts descending, a phase comparison is made between the reference signal and the received signal shown in FIG.

In this method, the total number of delay elements is the same as in the case of Fig. 1, but since only the output signal from the final stage element is used, a multiplexer is not required.
The circuit is simplified.

Note that since the sampling time of the reference signal is a long time (n×Δt), it is necessary to suppress the movement of the mother ship as much as possible during that time.

Further, in FIG. 6, a time gate circuit Gk equal to the delay time Δt is provided before the first stage delay element d1, and all reference signals entering the delay circuit are limited to the time width of Δt as shown in FIG. 7a. Since each delay element outputs this reference signal with a delay time of Δt as shown in b1 to bn in the same figure, a multiplexer can be used by simply taking the chord of these outputs using an adder circuit. The reference signal sequence C in the same figure can be obtained with a sampling time of Δ without any problems.

Therefore, by comparing the reference signal with the received signal shown in d of the same figure, the moving speed or distance can be measured.

Note that the reference signal and the received signal described above may be converted into rectangular waves and their phases may be compared.

As described in detail above, according to the present invention, the reference signal sampled at the reference point can always be reproduced in the moving body by the total delay circuit, and therefore the reference signal receiving section is placed at a different position from the moving body. No need to install.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the case where a capsule is lowered using the method of the present invention, and FIGS. 2, 4, and 6 are configurations showing different embodiments of the reference signal reproduction circuit used in the method of the present invention. 3, 5, and 7 are waveform diagrams of signals at each part of the circuit, respectively. DESCRIPTION OF SYMBOLS 1... Signal source, 3... Capsule, d1-do... Delay element.

Claims (1)

[Claims] 1. The reference signal received by the mobile body at the reference point from the signal source is inputted into a delay circuit in which all the delay elements are connected in series, and the output is obtained at a certain delay time. A method for measuring moving speed and distance, characterized in that the entire signal is reproduced, and the moving speed or distance is measured from a change in the phase difference between the reproduced reference signal and the received signal at the current position of the moving body.