DE1523144B2 - ARRANGEMENT FOR COMPENSATION OF FLUCTUATIONS IN SOUND SPEED IN WATER IN WATER SOUND DEVICES USING THE DOPPLER PRINCIPLE - Google Patents

Description

3 4

Ship bottom and bottom or in any other suitable way a mean wavelength of λ depth is calculated. This provides mm especially at = 14.65 and receive for 2 λ a distance zwistarken temperature gradient the advantage that a see sender S and receiver E of 29.3 mm. The better compensation value than near the surface this distance is fixed. The in F i g. 1 not achieved and at different sound speeds 5 shown mechanical holder is made from a speed over the measurement section of the sound log of the sound material, which is used in the temperature range between speed mean value. see 0 and 30 ° C only an expansion of below in the drawing are exemplary embodiments of the orderly meaning.

Subject of the invention shown, namely shows the bandpass filter BP is designed so that a

F i g. 1 a constant 2 generator in a first io limitation of the exciting natural frequencies

Execution that results in a frequency range of / _s = 95 to 105 kHz.

F i g. 2 a constant-2 generator in another To avoid excessive flow velocities of the

Execution. To avoid water W in the measuring section M,

In the measurement section M of FIG. 1 becomes a Schwin- it is sufficient to arrange the latter in a bypass,

ger than transmitter S excited. In the distance 15 It is not absolutely necessary, as assumed in this numerical example, the distance of the measuring section M

. _ 2 3 _ 4 A. to choose four half wavelengths; man

2 can also be more or less - generally η -

choose half wavelengths, but at most so

a transducer is fixedly arranged as a receiver E , 20 many that the value 100 / λι is not smaller than that

to an amplifier V with the following band percentage of the change in the sound velocity

Your passport is connected to BP. The bandpass filter BP ensures keitc.

* for the fact that the transmission frequency / _{s is} only in such Instead of the receiver £ in F i g. 1 can be used as

Can excite natural frequencies that occur- limiting the measuring section M also a reflector

cover the range of the speed of sound c. 25 RE can be used, whereby the excitation of the

Behind the bandpass filter BP follows a tube R with another S in the manner known per se according to FIG. 2

closed transformer TR, via whose output takes place; here is a magnetostrictive one as an example

gang selected the transmission frequency / _s for exciting the echo converter MW .

signal transmitter on the one hand and for tracing back to the taking advantage of the impedance of the water W,

Transmitter S on the other hand are decoupled. 30 .. - _r . . j-mrfw 171 * 1- · λ

A numerical example explains the mode of operation of the dxe for eigenvalue excitation of the measuring section M at η · _y

Device closer. is marked by Z - => - 00, a return setpoint ζ. B. a transmission frequency / _s in the range of coupling circuit can be selected with the interposition of a 100 kHz and a range of the bandpass filter BP is built up, which works so that

Speed of sound c from 1400 to 1530 m / s in 35 _an integral number of standing A-wave trains

To expect water W , this means an assignment & β 2 ^b

Acceleration from 1465 m / s + 4.5% to 100 kHz + 4.5%. builds up as an eigenvalue.

1 sheet of drawings

Claims (3)

1 2 ■ Transmission frequency measurement error · νρη ± 4.5 Vo around a patent claim: mean value can occur. ,: ... ■■■ “· That is why facilities were built that with 1. Arrangement for the compensation of Schwan temperature sensors the influence of the temperature the speed of sound in water in 5 consider the speed of sound. These the Doppler principle, especially for measuring devices, however, are operating and circuitry Path and / or speed of technically complex and satisfying in practice Watercraft, not exploiting water-borne use. Devices that radiate into the open water There are already facilities known Gewor echo signal transmitter, one the reflected waves io that work without temperature sensor and with the receiving receiver and the difference instead of which with a sound propagation between the transmitting and receiving frequency determin- measuring system in the Outside water included as a reference variable for mendes measuring device, with a fixed measuring section flooded by a compensation circuit (USA patent specification water) or with an interference switch for the tendency arrangement for detecting the respective control circuit (German Auslegeschrift 1094 471) gear -Sound velocity and for correction which is used to introduce a correction variable into the Doppler measured values, characterized in that the correction order is changed to a known sound frequency. These Lo-way is formed as a constant-A-generator solutions, however, provide mainly because of erforderder the transmission frequency (/ _sec) of the echo signal transmitter 20 loan outlay on circuitry not bebestimmt, friedigenden way to bypass the existing 2. Arrangement according to claim 1, which poses technical measurement problems. indicates that between the constant-A genes- The present invention is based on the finding rator and the echo signal transmitter a frequency from that one multiplies circuit complexity or frequency scaler, if one uses the reciprocal of the double is tet. lermessungen critical quotient f _s / c, so the 3. Arrangement according to claim 1 or 2, because the wavelength λ of the Dppplermessung expressed by that the measurement section (M) is attached in radiated sound, as a constant reference variable of a towing device that can be lowered. Frequency control loop, in which 30 the transmission frequency as a function of the actual speed of sound in the transmission ; medium, d. H. in sea or river water. For this purpose, the technology used in aviation measurement technology is used to measure the air flow velocity The invention relates to an arrangement for grain, 35 known constant A generator for the compensation of fluctuations in the sound velocity - Doppler measurement by water as the transferability in the water in the Doppler principle, especially a medium for determining movement over the ground made serviceable for measuring the distance and / or the speed. ability of watercraft, exploiting water This is done according to the invention in that sound devices that emit an echo signal transmitter that radiates into the open water 40 the correction arrangement in a manner known per se, one of the reflected waves is designed as a constant A generator that determines the receiving receiver and the difference between the transmission frequency of the echo signal transmitter,
see transmit and receive frequency determining the fixed measuring section is from the one Measuring device included, with a one flooded with water, in which the Doppler principle is used for the flooded fixed measuring section containing the 45 measurement, while the constant A generation for recording the respective sound velocity from two temperature-independent fixed arrangement and for correction of the measured values. _ne t _en transducers as a resonance section with stand- It is known to use a so-called Doppler wave of one or more half-wave sound logs to measure the path and speed of a ship for a length of time and based on a known reason, with the path being the time integral of the 50 wise (cf. German patent 811 965) a speed is gained. The mathematical self-excitatory system works.
Analysis of the speed used to determine the transmission frequency obtained in this way can, however The frequency deviation of the received frequency used also initially on a constant-2 generator frequency from the transmit frequency shows that this downstream frequency multiplier or lower value of the frequency deviation Af is not only switched by the setter before the resulting speed ν des Watercraft itself, but frequency excited the echo signal transmitter. The acoustic part of the device is also preferred to the transmission frequency / _s and the reciprocal of this path, especially when the speed of sound c in water is proportional ; ■■ ^; · ·; ■ to compensate for fluctuations in the sound ^ j L. / ⁶ ° speed in the water, which changes after the entry c ^s ' must set up construction options on the watercraft, an acoustic influence on the receiver for the Now the value of the speed of sound fluctuates according to the Doppler principle. is known as a function of temperature and The device described can also be used in Salinity of the water. Thus, a measuring section, for example, 65 apply, the constant-A-Gene-sound velocities reasonable between c = 1400 m / s and not rator directly on the watercraft c - 1530 m / s occur, is introduced according to the season and salt, but in a lowerable drag level. This means that when the device is kept constant, it is roughly in the middle between