JPH063440A - Apparatus for measuring uneveness of ground surface or the like for missile - Google Patents

Abstract

PURPOSE:To enable simultaneous measurement of uneveness of the ground surface or the sea surface below a missile in flight and changes in absolute altitude of the body of a small missile. CONSTITUTION:Altimeters 2 and 3 which emit beams to determine a terrain clearance by measuring the reflection thereof are mounted on a missile 1 being shifted longitudinally so as to keep the beams from overlapping each other. Altitude outputs of the altimeters 2 and 3 undergo a signal processing with a signal processing device 5 to separate changes in absolute altitude of the flying object 1 and irregularities 6 of a ground surface or sea surface under the missile 1. In addition, a gyroscope 4 is mounted on the missile 1 and an output of a pitch angle is used to achieve higher accuracy of functions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is based on the altitude output of two altimeters attached to a projectile, and determines the terrain under the projectile, the ground structure,
Separation of waves or other irregularities on the ground or sea surface,
The present invention relates to an altitude measuring device that detects these and at the same time accurately measures a change in absolute altitude of a flying object.

[0002]

2. Description of the Related Art As a device for measuring the altitude of a flying object,
There are barometric altimeters and radio altimeters. The barometric altimeter is not affected by the unevenness of the ground or the sea surface (hereinafter referred to as "ground, etc.") below the flying object, but it is sensitive to changes in the air flow around the flying object, and is at the same altitude while the flying object is rising and falling. However, the altitude output may not exactly match. In addition, irregular airflow during turning may cause abnormal altitude output, which poses a problem in accurately measuring the change in absolute altitude of the flying object. Further, since the altitude measurement by the radio altimeter measures the distance between the flying body and the ground or the like below the flying body, it is impossible to separate the change in the absolute height of the flying body from the irregularity of the ground or the like below the flying body.

[0003]

[Problems to be Solved by the Invention] Attached to a flying object,
The altitude output of the altimeter (hereinafter referred to as "altimeter"), which emits a beam and measures the ground altitude using its reflection, includes not only the change in the absolute altitude of the projectile body, but also irregularities such as the ground below the projectile. Has been. As a method of separating these two pieces of information, it is conceivable to calculate the change in the motion and attitude of the flying body in the flight state from the outputs of the accelerometer and the gyro and correct the altimeter output by this method. The device is complicated and it is difficult to obtain reliable results due to the difference in characteristics of different kinds of equipment.

The present invention has been made in view of the above problems, and can be used to accurately measure unevenness of the ground or the like under a flying object and to accurately measure changes in absolute altitude of the flying object. It is an object of the present invention to provide an unevenness measuring device.

[0005]

In order to achieve the above object, an apparatus for measuring unevenness of a ground for a flying object according to the present invention is defined by claim 1.
Then, as shown in FIG. 1, two identical altimeters 2 and 3 which emit beams of radio waves, light waves, sound waves, etc. and measure the altitude with respect to the ground by using their reflection 8 is attached to the flying body 1 so that they do not overlap with each other, and the signal processor 5 that calculates using the altitude output of the two altimeters 2 and 3 makes the flying body 1 and the unevenness 6 of the ground or sea under the flying body 1 in flight. The feature is that the change in absolute height of one body can be separated.

In the second aspect, the signal processor 5 according to the first aspect may be configured such that the output of the gyro 4 for measuring the pitch angle of the flying object 1 is added to perform calculation.

[0007]

According to the above structure, the two altimeters 2 and 3 are emitted from the flying body 1 toward the unevenness 6 on the ground or the sea so that the beams 7 and 8 do not overlap with each other.
Therefore, by calculating the reflection state of the beams 7 and 8 by the signal processor 5, it is possible to separately obtain the unevenness 6 of the ground or sea surface under the flying body 1 and the change in the absolute height of the flying body 1.

Further, if the output of the pitch angle measuring gyro 4 is further obtained with respect to the signal processor 5, it is possible to cope with the change in the pitch angle of the flying object 1 and improve the accuracy of the above-mentioned function.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a configuration diagram showing an embodiment of the unevenness measuring apparatus for the ground for a flying object of the present invention. In the figure, 1 is a flying object, 2 and 3 are altimeters that measure the altitude of the ground by reflecting the beams, 4 is a gyro for pitch motion measurement of the flying object, 5 is a signal processor, and 6 is the ground below the flying object. Etc., 7 is the beam of altimeter 2 and 8 is the beam of altimeter 3.

As shown in FIG. 1, in addition to an altimeter 2 attached to a flying body 1 with a beam 7 directed directly below it, an altimeter 2
The second altimeter 3 is attached so that the beams 7 and 8 do not overlap in front of. The angle between the beams of the altimeter 2 and the altimeter 3 is θ.

Next, as shown in the principle explanatory view of FIG. 2, the flight direction of the flying object 1 is taken as the x-axis, and the altitude output of the altimeter 2 at the position x0 on the x-axis of the flying object 1 is f1, the altimeter. The altitude output of 3 is f2. When the flying object 1 flies over a surface having irregularities, the absolute height of the flying object, the irregularities 6 such as the ground, etc. are each expressed as a function of the position x on the x-axis with respect to the virtual level surface.
(X) and g (x), the altitude output f1 of the altimeter 2
Is expressed by the following equation.

[0012]

[Equation 1]

On the other hand, the beam 8 of the altimeter 3 is reflected from the point of position x1 on the x-axis expressed by the following equation.

[0014]

[Equation 2]

Further, f2 is expressed by the following equation using the unevenness g (x1) of the ground or the like at this point.

[0016]

[Equation 3]

When h (x0) is deleted from the equations 1 and 3, the following equation is obtained.

[0018]

[Equation 4]

The left side of the equation 4 is obtained by Taylor-expanding g (x1) with the second term on the right side of the equation 2 as a minute amount, and taking the first-order expansion of a minute amount, the derivative of g (x) at the position x at x0. Is expressed as follows.

[0020]

[Equation 5]

Rewriting equation 4 using equation 5 yields the following.

[0022]

[Equation 6]

That is, the differential of the unevenness g (x) of the ground or the like with respect to the position x is represented by two altitude outputs f1 and f2 and a known amount θ. Then, the product of the right side of Equation 6 is g (x), which is the unevenness of the ground itself.

Therefore, as shown in FIG. 3, the signal processor 5 obtains the unevenness of the ground or the like by using g (x) obtained based on the above equation (6). Further, the signal processor 5 uses this g (x)
The absolute height h (x) of the flying object 1 can be obtained by performing a calculation to obtain h (x) by using Equation 1 and

Next, FIG. 4 is a principle explanatory view showing a second embodiment of the present invention. As shown in FIG. 4, in this embodiment, a gyro 4 is used in addition to the structure of the first embodiment. The gyro 4 obtains the pitch angle output p for correcting the change in the attitude of the flying object 1, especially the change in the beam direction due to the pitch movement. As shown in FIG. 4, when the pitch angle of the flying object 1 is p, the position on the x axis of the flying object 1 is x0, and the position on the x axis of the point where the beam 7 of the altimeter 2 hits the ground or the like is x.
1. If x2 is the position on the x-axis of the point where the beam 8 of the altimeter 3 hits the ground or the like, x1 is expressed by the following equation.

[0026]

[Equation 7]

Further, x2 is expressed by the following equation.

[0028]

[Equation 8]

Eliminating x0 from the equations 7 and 8 gives the following equation.

[0030]

[Equation 9]

Altimeter outputs f1 and f2 of altimeter 2 and altimeter 3
The following relational expression 10 holds.

[0032]

[Equation 10]

In the latter means, the second term and the third term on the right side of the equation 9 are used as minute amounts and the position differential of g (x) with respect to x1 is used to obtain the equation 11 in the same manner as in the case where p is not included. , G (x) can be obtained by integrating this. The signal processor 5 obtains the unevenness of the ground or the like from g (x) obtained by the calculation shown in FIG.

[0034]

[Equation 11]

As described above, the signal processor 5 calculates the altitude output of the two altimeters 2 and 3 and the pitch angle output of the gyro 4 to calculate the absolute altitude of the flying object 1. At the same time as measuring the change, it is possible to measure the unevenness of the ground or the like under the flying body 1.

[0036]

As described above, according to the apparatus for measuring unevenness of the ground for a flying object of the present invention, it is possible to precisely measure the unevenness of the ground under the flying object from the flying object which is difficult in the past. It also enables precise measurement of changes in absolute altitude of a flying object.
Further, since this method has a simple equipment structure, it can be mounted on a small flying object to fulfill the above-mentioned functions.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of an unevenness measuring device for a ground for a flying object of the present invention.

FIG. 2 is an explanatory diagram showing the principle of the device.

FIG. 3 is a diagram showing the contents of calculation of the device.

FIG. 4 is an explanatory diagram showing the principle of another embodiment of the present invention.

FIG. 5 is a diagram showing calculation contents of the apparatus.

[Explanation of symbols]

1 ... Flying object, 2 ... Altimeter, 3 ... Altimeter, 4 ... Gyro,
5 ... Signal processor, 6 ... Ground or sea surface, 7 ... Beam of altimeter 2, 8 ... Beam of altimeter 3.

Claims (2)

[Claims] 1. Two altimeters (2) and (3) which emit the beam of radio waves, light waves, sound waves and the like and measure the altitude to the ground by using the reflection of the beams (2) and (3) respectively in the front and rear directions. ) (8) is attached to the projectile (1) so that they do not overlap, and a signal processor (5) that calculates using the altitude output of two altimeters (2) and (3) is used to A device for measuring unevenness of a ground such as a flying body, which is capable of separating changes in absolute height of the flying body (1) from unevenness (6) of the ground or sea surface. 2. The signal processor (5) according to claim 1, wherein
An unevenness measuring device for the ground for a flying object, which is calculated by adding the output of a gyro (4) for measuring the pitch angle of the flying object (1).