JPH02287276A - Speed measuring apparatus - Google Patents

Abstract

PURPOSE:To eliminate the adverse effect of the noise of a movement propelling source and to stably measure a speed with high accuracy by emitting sonic wave beam in four directions of forward left, forward right, backward left and backward right to perform vector coordinates transformation. CONSTITUTION:Sonic wave beams 8a - 8d in four directions of forward left, forward right, backward left and backward right are arranged to a transmitter-receiver 6 at the same dip with respect to the moving direction of a moving body and driven by a transmitter 9. The reflection signals thereof are respectively received and amplified by receiving amplifiers 11a - 11d and the outputs of said amplifiers are respectively detected by Doppler transform detection means 12a - 12d. Next, the speed component in the forward left direction is detected on the basis of the difference of Doppler transform between the forward left direction and the backward right direction by a Y-axis speed detection means 13y and the speed component in the forward right direction is detected on the basis of the difference of Doppler transform between the forward right direction and the backward left direction by an X-axis speed detection means 13x. As a result, by transforming the obtained speed components in the forward left and forward right directions to a forward and backward speed and a left and right speed by a vector coordinates transformation means 14, the mixing of propeller noise is eliminated and stable measurement of high accuracy can be performed.

Description

[Detailed description of the invention] (Industrial application field) The present invention utilizes the Doppler effect of sound waves to create a mobile object.

For example, it relates to a device that determines the speed of a ship by 1 (III).

(Prior art) The speed constant device for ships, conventionally known by names such as Dotsupura sonar, works on the first-order principle, that is, a sound wave emitted diagonally downward from the bottom of the ship and a wave floating on the seabed or underwater. The ship's speed is measured using the principle that a Doppler shift proportional to the ship's speed occurs between the received signal that is scattered and reflected by objects and received again. Such a speed measuring device for a ship employs an error reduction method called the JANUS method for the purpose of reducing measurement errors caused by tilting or oscillation of the ship. This method emits sound beams in symmetrical directions, for example, forward and backward.

The error is reduced by the difference in Doppler shift of each sound beam.

In addition, as an example of the prior art, as shown in FIG. 4, a transducer 2 is attached to the hull 1, and from this transducer 2, a sound wave beam 3a in the forward direction and a sound wave beam in the rear direction with respect to the moving direction are emitted. 3b, a rightward sonic beam 3C and a leftward sonic beam 3d are emitted. Then, the longitudinal speed nj is determined from the reflected waves of the forward and backward sound beams 3a and 3b, and the left and right speed nj is determined from the reflected waves of the rightward and leftward sound beams 3C and 3d. Such a speed measuring device is called a two-axis speed measuring device, and is widely put into practical use.

(Problems to be Solved by the Invention) However, such a two-axis speed measuring device that simultaneously measures longitudinal speed or lateral speed has the following problem. In other words, the rotation noise of the propeller 4, which serves as a mobile propulsion source for ships, is the cause, commonly known as "propeller noise".
A backward beam 3b arranged to measure forward and backward movement of the noise 5 caused by multiple reflections between the ship's hull 1 and the seabed, etc.
be mixed into the For this reason, the 71111 constant value of 1 forward/backward degree tends to include an error.

Therefore, a technical problem of the present invention is to provide a speed determination device that can measure the speed without including noise caused by the moving propulsion source of a moving body.

(Means for Solving the Problems) The speed measuring device according to the present invention has a sound wave beam arrangement in four directions consisting of front, front cloth, rear left, and rear right with respect to the moving direction of a moving object at the same depression angle. a transducer, a transmitter for driving the transducer, a reception amplification means for amplifying the reflected signals of the sound wave beams in the four directions, and a Doppler shift frequency in the four directions from the output of the reception amplification means. Doppler shift detection means for detecting a Doppler shift; first velocity detection means for detecting a velocity component in the front left direction based on a difference between the Doppler shift in the front left direction and the rear right direction; a second velocity detection means for detecting a velocity component in the front right direction based on a difference in Doppler shift in the direction; and a velocity component in the front left direction obtained by the first velocity detection means and the second velocity detection means vector coordinate conversion means for converting these velocity components into longitudinal velocity and lateral velocity of the moving body based on the longitudinal velocity components obtained by It is characterized by containing.

(Function) The speed ρ1 constant device according to the present invention transmits four sound wave beams to the front, front cloth, rear left,
By emitting in the rear-right direction, these reflected waves do not include the sound waves of the mobile propulsion source, which is usually installed at the rear of the mobile object.

Furthermore, what is obtained by detecting the Doppler shift of the four reflected waves mentioned above are velocity components in the forward direction and front right direction, and these velocity components are transformed into velocity components in the longitudinal direction and left and right directions using vector coordinate conversion means. Convert to

(Example) Two embodiments of the present invention will be described below.

FIG. 1 is a diagram showing the arrangement of sound wave beams according to the present invention, in which the transducer 6 attached to the hull 1 has the same depression angle 2.
For example, at 60 degrees, with respect to the moving direction, a sonic beam 7a in the front left direction, a sonic beam 7c in the front right direction, a sonic beam 7d in the rear left direction, and a sonic beam 7b in the rear right direction are generated. By arranging the sound wave beam in this way, the directivity gain in the direction of the propeller 4 installed at the rear of the hull is reduced, so even if multiple reflections occur between the hull 1 and the seabed, the propeller noise 5 is reduced. There is almost no possibility that it will be mixed into the transducer 6.

FIG. 2 is a configuration diagram showing an embodiment of a speed measuring device for measuring longitudinal speed and lateral speed using a transducer having the sonic beam arrangement shown in FIG. 1. 6 is a transducer,
8a to 8d are vibrators, 9 is a transmitter, 10a to 10d are transmitting/receiving switching devices, 11a to 11d are receiving amplifying means, 123 to 1
2d is a Doppler shift detection means, 13x is an X-axis speed detection means, 13y is a Y-axis speed detection means, 14 is a vector coordinate conversion means, 15f is a longitudinal speed indicator, and 15s is a left-right speed indicator. The transducer 8a emits the sound wave beam 7a in the front left direction as shown in FIG.
The transducers 8d each generate a sound wave beam 7d in the rear left direction.

During wave transmission, the transmitter 9 generates a transmission pulse of frequency f, and drives the transducers 88 to 8d via the transmission/reception switching devices 10a to 10d.

At the time of wave reception, the sound waves in each direction are scattered and reflected by objects floating on the seabed or in the water 1'', and undergo a Doppler shift according to the relative speed between the ship and those reflecting objects, and are again transmitted to the transducers 8a to 8d.
The wave is received by These signals are sent to the transmitter/receiver switchers 10a to 10.
d, the signal is amplified to an appropriate magnitude by reception amplification means 11a to lid, and the Doppler shift frequency is detected by Doppler shift detection means 12a to 12d. Doppler shift detection means 12
g is the Doppler shift frequency Δf in the front left direction, and the Doppler shift detection means 12b is the Doppler shift frequency Δf in the rear right direction.
f5, the Doppler shift detection means 12c detects the Doppler shift frequency Δfc in the front right direction, and the Doppler shift detection means 12d
outputs the Doppler shift frequency Δf in the rear left direction, respectively.

Next, in the Y-axis speed detection means 13y, according to the following equation (1),
Find the speed in the forward left direction (Y-axis).

Here, C represents the speed of sound, and θ represents the angle of depression of the sound beam. In this formula, as mentioned above, the speed is calculated from the difference in Doppler deviation in order to reduce measurement errors caused by the ship's heel and oscillation. Similarly, the speed in the front right direction (X-axis) is determined using the following equation (2) using the X-axis speed detection means 13x.

For the forward left direction (Y-axis) speed V and the forward right direction (X-axis) speed V8 obtained in this way, ■ is the ship speed.

Let α be the angle at which the ship is actually traveling as seen from the bow.

These relationships are shown in Figure 3.

π V, 1-V-cos(--a) -(3)
Furrow saturation V, -V Φ5fn(--a) -(
4) vP-v @cos a
-(5)v5=V-sin a
-(6) The following relationship is derived from these four equations.

From these equations (7) and (8), based on the forward left direction (Y-axis) speed V and the forward right direction (X-axis) speed V8, the vector coordinate conversion means 14 calculates 2 forward and backward speeds vP and lateral speeds Vs.
is determined and outputted to and displayed on the 2 longitudinal speed indicator 15f and the left/right indicator 15s, respectively.

(Effect of the invention) As explained above, in the present invention, old friend, front cloth, back left,
In order to find the longitudinal velocity or lateral velocity using a transducer with a beam arrangement in the rear right direction and vector coordinate conversion means,
This method has the advantage of eliminating the influence of noise from mobile propulsion sources and allowing stable and highly accurate ship speed measurements.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the arrangement of sound wave beams according to the present invention, FIG. 2 is a block diagram showing an embodiment of the device of the present invention, and FIG.
The figure is a diagram for explaining vector coordinate transformation according to the present invention, and FIG. 4 is a diagram showing the arrangement of conventional sound wave beams. 1... Hull, 2... Transmitter/receiver, 3a to 3d... Sonic beam, 4... Propeller, 5... Propeller noise,
6... Transducer/receiver, 7a-7d... Sound wave beam, 8a
~8d... Vibrator, 9... Transmitter, 10a-10d
...Transmission/reception switching device, 11a to 11d...Reception amplification means, 12a to 12d...Doppler shift detection means 11
3y...Y-axis speed detection means, 13X...X-axis speed detection means, 14...Vector coordinate conversion means, 15f...
- Forward/rear speed indicator. 15s...Left and right speed indicators.

Claims (1)

[Claims] 1. A transducer that has a sonic beam arrangement in four directions, front left, front right, rear left, and rear right, with respect to the moving direction of the moving body at the same depression angle, and a transmitter that drives the transducer. a receiving amplifying means for amplifying reflected signals of the sound wave beams in the four directions, Doppler shift detecting means for detecting Doppler shift frequencies in the four directions from outputs of the receiving amplifying means; a first velocity detection means for detecting a velocity component in the front left direction based on a difference between Doppler shifts in the rear right direction; and a velocity component in the front right direction based on a difference between Doppler shifts in the front right direction and the rear left direction; a second speed detection means for detecting;
Based on the velocity component in the front left direction obtained by the first velocity detection means and the velocity component in the front right direction obtained by the second velocity detection means, these velocity components are calculated as the longitudinal velocity of the moving body and A speed measurement device comprising: vector coordinate conversion means for converting into lateral speed; and a speed indicator for displaying the longitudinal speed and lateral speed.