JPH0670634B2 - Supersonic velocity measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the flight speed of a projectile having a linear orbit at a supersonic speed such as a bullet or shell.

[0002]

2. Description of the Related Art A conventional sensor used for measuring the velocity of a flying object is linear or optical. The linear shape is a shape in which a conductive wire material is stretched around, and the wire material is broken at the moment when the flying object passes through the linear material, and this is electrically detected. Optically, it is a shape in which a light beam consisting of a light projecting and receiving light is stretched around, and intercepts the light beam at the moment when the flying object passes through this light beam, and electrically detects it.

These targets (linear or optical) are arranged at two points on the trajectory of the flying object, and the moment when the flying object passes each target is detected, and the time difference (T) between these detection timings is detected. From the distance L between the targets, the velocity of the flying object v = L / T
Was generally used.

[0004]

From the principle, linear or optical requires a target-like shape, and the flying object needs to pass through the inside of a region designated by the target shape.
However, apart from the case where the trajectory of the flying object can be controlled stably, there is a risk that bullets and shells will be displaced from the specified area, so there is an accident that the target structural part is shot and the sensor is destroyed. There is. In order to prevent such an accident, if an attempt is made to expand the measurable area, a large structure corresponding to the area is required, which is burdensome in terms of cost and inconvenient to handle.

The present invention uses a small sensor that detects a shock wave instead of the conventional linear or optical one, and there is no fear of being destroyed by a flying object with a deviated orbit. It is intended to realize a convenient measuring device of.

[0006]

The supersonic projectile velocity detection sensor of the present invention is arranged at a predetermined distance L on a straight line parallel to the standard trajectory of the supersonic projectile to be measured. First and second shock wave detection sensors, and
A time interval for measuring the time interval T between the first and second waveform shapers for respectively shaping the detection output of the second shock wave detection sensor and the respective outputs of the first and second waveform shapers. The measurement data of the measuring instrument and the time interval measuring instrument are input, and the velocity v of the flying object to be measured is calculated by using the preset interval L between the first and second shock wave detection sensors.
An arithmetic unit for calculating L / T is provided.

[0007]

[Example] In a state where a flying object has a linear trajectory at a constant supersonic velocity, a conical shock wave is generated with the trajectory as an axis and the current position of the flying object as an apex. Now, let us say that the speed of sound is c, the velocity of the flying object is v, and the cross section of the shock wave at the moment when the flying object is at the point P ₂ is illustrated in FIG. That is,
The cross section of the shock wave becomes straight lines L ₁ and L ₂ . Before from the moment there is a projectile in the position of the point P ₂ by a time t, it is assumed that there is flying object to the position of the point P _1, make a vertical line from the point P ₁ to the straight line L _2, the intersection between P ₃ To do. Waves projectile occurs when you present to the point P ₁ is present, that is when the projectile comes to the point P ₂ is the radius P ₁ P ₃ around the point P ₁
Spreads in a spherical shape. The circle 10 shown by the dotted line in FIG.
It is a cross section of the spherical surface. Therefore, the length of the straight line P ₁ P ₃ is ct. However, c is the speed of sound. In addition, straight line P ₁ P ₂
Is vt, the apex angle α of the shock wave cone is expressed by the following equation.

Α = sin ⁻¹ (P ₁ P ₃ / P ₁ P ₂ ) = sin ⁻¹ (ct / vt) = sin ⁻¹ (c / v) (1) Therefore, the velocity v of the flying object is constant. As long as the cone-shaped shock wave is present, it can be seen that the apex angle α moves on the trajectory 9 without changing at the time t. As shown in FIG. 1A, a small straight line 10 passing through the centers of small first and second shock wave detection sensors S _A and S _B such as an ultrasonic microphone and a pressure sensor is used.
Is arranged so as to be parallel to the standard trajectory 13 of the flying object, the time interval T between the shock waves detected by the first and second shock wave detecting sensors S _A and S _B is equal to the interval between these sensors. Equal to the moving time interval. This will be described with reference to the drawings.

The positions of the sensors S _A and S _B are set to A and B, respectively.
Assuming that the position of the flying object at the moment when the sensor S _A detects the shock wave is P _A and the position of the flying object at the moment when the sensor S _B detects the shock wave is P _B , the straight lines AP _A and BP _B are as shown in FIG. As described above, the angle between the standard trajectory 13 of the flying object and the straight lines AP _A and BP _B corresponds to the cross section of the shock wave, and the apex angle α of the shock wave
be equivalent to. Since the angle α is common and the straight line AB and the straight line P _A P _B are parallel, ABP _B P _A is a parallelogram.

Therefore, the length of the straight line AB is the straight line P _A P _B
Equal to the length of, and let this be L. First and second sensor S
Letting T be the time difference between the timings when _A and S _B detect the shock wave, the velocity v of the flying object is obtained by the following equation. v = L / T (2) The respective detection outputs of the first and second shock wave detection sensors S _A and S _B (a and c in FIG. 1B) are waveform-shaped through the waveform shapers D _A and D _B , respectively. , The pulse-shaped shaping outputs (B and B in FIG. 1B) are input to the time interval measuring device E, and the time difference T _A between the rising times t _A and t _B of the shaping outputs T =
t _B −t _A is measured, and the measured data is supplied to the calculator F.

The calculator F calculates the velocity v of the flying object by dividing the preset interval L between the first and second sensors S _A and S _B by the input data T, and displays the velocity data. It is supplied to G and is output to the outside through the output terminal OUT as needed. First and second shock wave detection sensors S _A , S _B
The straight line 10 parallel to the standard orbit 13 in which the sensor is placed is provided at a sufficient distance from the standard orbit 13 so that these sensors are not destroyed by a projectile with a deviated orbit.

[0012]

According to the present invention, the small first and second shock wave detection sensors are provided in place of the conventional linear and optical distances to a sufficiently safe place with respect to the standard trajectory 13 of the flying object to be measured. Moreover, since they can be arranged on the parallel straight lines 10, there is no risk of destruction by a flying object with a deviated orbit.

In the present invention, since it is easy to separate the first and second sensors from the standard orbit 13, it is possible to widen the speed measurable region as necessary as compared with the conventional linear or optical device. Its handling is extremely convenient. Moreover, this does not impose any financial burden.

[Brief description of drawings]

FIG. 1A is a block diagram of the present invention, and B is a waveform diagram of a main part of A.

FIG. 2 is a cross-sectional view for explaining the shape of a shock wave generated by a flying object.

Claims (1)

[Claims] 1. A first and a second shock wave detection sensors, which are arranged on a straight line parallel to and apart from a standard trajectory of a supersonic flying object to be measured, with a predetermined distance L, and the first and second shock wave detection sensors. First and second waveform shapers for respectively shaping the detection outputs of the shock wave detection sensor, and a time interval measuring device for inputting the respective outputs of the first and second waveform shapers and measuring the time interval T between them. And input the measurement data of the time interval measuring device, and using the preset interval L between the first and second shock wave detection sensors, the velocity v of the measured supersonic flying object.
= L / T, and a calculator for calculating L / T.