Determination of distances and audibility of sounds on the ground and target designation
All benefits for travelers: tourists, hunters - always give a great place to the methods of determining the distances to any objects without the help of special tools. Of course, skill is not out of place. I think, however, that in preparation for crossing the river, you will lose a little if you determine its width of 75 meters, although in fact it is 120 meters. Well, you have to row a few minutes longer - what will change. It is much more important to be able to determine not the width of the crossing, but to find a place good for it, to find out the depth and nature of the ford (more on that below). It is important for the hunter to know exactly the distance, for example, to the moose lying in the snow in order to correctly take the excess of the fly and to get the beast with one shot. This is achieved not only with great practice, but also with the help of special techniques and devices, which in turn help this practice.
Very often it is required to determine the distances to various objects on the ground, as well as evaluate their size. The distances are most accurately and quickly determined by means of special devices (range finders) and range-finder scales of binoculars, stereo tubes, sights. But due to the lack of devices, distances are often determined using improvised means and by eye.
The simplest methods for determining the distance (distance) to objects on the ground include the following:
- according to the linear sizes of objects;
- by visibility (distinguishability) of objects;
- according to the angular size of known objects;
- by sound, etc.
Eyeballing is the easiest and fastest way. The main thing in it is the training of visual memory and the ability to mentally put off a well-represented permanent measure (50, 100, 200, 500 meters) on the ground. Having fixed these standards in memory, it is easy to compare with them and evaluate distances on the ground. By reference An example of using the eye method for determining distances in pictures .
When measuring distance by successively mentally putting aside a well-studied constant measure, it must be remembered that the terrain and local objects seem to be reduced in accordance with their removal, that is, when removed twice, the object will appear to be half as much.
Therefore, when measuring distances, mentally delayed segments (measures of terrain) will decrease according to distance.
In doing so, consider the following:
- the closer the distance, the clearer and sharper the visible object seems to us;
- the closer the subject, the more it seems;
- Larger objects appear closer to small objects at the same distance;
- a brighter object appears closer than a dark object;
- brightly lit objects appear closer to dimly lit, located at the same distance;
- during fog, rain, twilight, cloudy days, when the air is saturated with dust, the observed objects appear farther than on clear and sunny days;
- the sharper the difference in the color of the object and the background on which it is visible, the more reduced the distance; for example, in winter, a snow field seems to bring closer dark objects on it;
- objects on flat terrain seem closer than on hilly, distances that are defined through vast bodies of water seem especially reduced;
- folds of terrain (river valleys, hollows, ravines), invisible or not fully visible by the observer, conceal the distance;
- when observing lying objects appear closer than when standing;
- when viewed from the bottom up - from the bottom of the mountain to the top, objects seem closer, and when viewed from top to bottom - further;
- when the sun is behind us, the distance is hiding, shining in the eyes - it seems larger than in reality;
- the fewer objects in the area under consideration (when observing through a body of water, an even meadow, steppe, arable land), the less distances appear.
The accuracy of the eye depends on the person’s training.
For a distance of 1000 m, the usual error ranges from 10-20%.
By linear dimensions
Determination of distances by the linear dimensions of an object (object)
The determination of distances by the linear dimensions of objects is as follows (Fig. 9). Using a ruler located at a distance of 50 cm from the eye, the height (width) of the observed object is measured in millimeters. Then the actual height (width) of the object in centimeters is divided by the measured in a ruler in millimeters, the result is multiplied by a constant number 5 and the desired height of the object in meters is obtained .
For example, the distance between telegraph poles equal to 50 m (Fig. 8) is closed on a ruler with a segment of 10 mm. Therefore, the distance to the telegraph line is:
The accuracy of determining distances by angular and linear values is 5-10% of the length of the measured distance. To determine the distances by the angular and linear dimensions of objects, it is recommended to remember the values (width, height, length) of some of them, shown in the table below
|Medium tank||2-2.5||6-7||3-3 5|
|Armored personnel carrier||2||5-6||2-2,4|
|Four-axle passenger carriage||4||twenty||3|
|Four-axle railway tank||3||nine||2,8|
|Wooden pole of communication line||5-7||-||-|
To determine the distance in this way, you must:
- keep the ruler in front of you at arm's length (50-60 cm from the eye) and measure the apparent width or height of the object in millimeters to which you want to determine the distance;
- divide the actual height (width) of the object, expressed in centimeters, by the apparent height (width) in millimeters, and multiply the result by 6 (a constant number), we get the distance.
For example, if a pillar with a height of 4 m (400 cm) is closed in a line of 8 mm, then the distance to it will be 400 x 6 = 2400; 2400: 8 = 300 m (actual distance).
To determine distances in this way, you need to know the linear dimensions of various objects well, or have this data at hand (on a tablet, in a notebook). The dimensions of the most frequently encountered objects must be remembered by a person, since they are also required for the method of measuring by angular magnitude, which is the main one for us.
By the visibility (visibility) of objects
With the naked eye, you can approximately determine the distance to targets (objects) by the degree of their visibility. For example, if someone saw a pipe on the roof of a house, this means that the house is no more than 3 km, and not exactly 3 km. A soldier with normal visual acuity can see and distinguish some objects from the following limit distances indicated in the table below:
|Objects and Features||
The distances from which they
|Separate small house, log hut||5 km|
|Chimney on the roof||3 km|
|Airplane on the ground tank in place||1 2 km|
|Tree trunks, kilometer poles and communication line poles||1.0 km|
|The movement of the legs and arms of a running or walking person||700 m|
|Easel machine gun, mortar, anti-tank gun, stakes of wire fences||500 m|
|Machine gun, rifle, color and parts of clothes on a person, oval of his face||250 - 300 m|
|Roof tiles, tree leaves, stakes wire||200 m|
|Buttons and buckles, details of the armament of a soldier||100 m|
|Human features, hands, small arms details||100 m|
It must be borne in mind that the table indicates the maximum distances from which certain objects begin to be visible. For example, if a soldier saw a pipe on the roof of the house, this means that the house is no more than 3 km, and not exactly 3 km. Using this table as a reference is not recommended. Each soldier must individually clarify these data for himself.
When eye distance determination is desirable to use landmarks, the distances to which are already accurately known.
By angular value
Determination of distances by the angular dimensions of an object (object)
The determination of distances by the angular dimensions of objects is based on the relationship between angular and linear values. The angular dimensions of objects are measured in thousandths using binoculars, observation and aiming devices, rulers, etc. To apply this method, you need to know the linear magnitude of the observed object (its height, length or width) and the angle (in thousandths) under which this object is visible.
For example, the height of the railway booth is 4 meters, the person sees it at an angle of 25 thousandths (the thickness of the little finger).
Then the distance to the booth will be 4 x 1000 = 4000 divided by 25, that is 160 meters.
To determine the angular value, you need to know that a segment of 1 mm, 50 cm from the eye, corresponds to an angle of two thousandths (recorded: 0-02).
From here it is easy to determine the angular value for any segments. For example, for a segment of 0.5 cm the angular value will be 10 thousandths (0-10), for a segment of 1 cm - 20 thousandths (0-20), etc.
The easiest way to memorize standard thousandths is by heart:
|Name of items||Size in thousandths|
|Middle finger thickness||35|
|Little finger thickness||25|
|Cartridge for the width of the barrel of the cartridge case (7.62 mm)||12|
|Sleeve 7.62 mm wide||eighteen|
|Match box length||60|
|Match box height||thirty|
The distance to objects in meters is determined by the formula: where B is the height (width) of the item in meters; Y is the angular value of the item in thousandths.
- the angular size of a landmark observed with binoculars (telegraph pole with a backup), whose height is 6 m, is equal to the small division of the binocular grid (0-05). Therefore, the distance to the landmark will be equal to:
- the angle in thousandths measured by a ruler located at a distance of 50 cm from the eye (1 mm is 0-02) between two telegraph poles 0-32 (telegraph poles are located at a distance of 50 m from each other). Therefore, the distance to the landmark will be equal to:
- tree height in thousandths, measured with a ruler 0-21 (true tree height 6 m). Therefore, the distance to the landmark will be equal to:
Determination of distance on the ground
To learn how to calculate distances, you first need to find out the length of your step, your height and the thickness of the finger with which you sight. In addition, it is necessary to get an idea of how far the horizon line lies from the observer. In other words, you need to know how far the hunter can view the surrounding area. For this purpose, one should use the formula: Horizon range = 113 √ h km , where h is the observer's height in km.
Standing on a plain, a person with a height of 1.6 m sees the surrounding area at 131 √ 0.0016 = 4.52 km. Sitting in a boat and rising above the water by only 1 m, a person can view the surrounding area only 113 √ 0.001 = 3.58 km. Of course, in reality, the horizon’s range increases, since the Earth’s atmosphere, bending the path of light rays (refraction), as it were, moves the horizon by about 6% compared with the figures obtained from the formula. Due to this, a person with a height of 1.6 m sees the surrounding area for 4.8 km. Horizon visibility also increases when atmospheric pressure rises, in cold weather, and also in the morning and evening.
But from what height and at what distance the horizon is seen:
For eye estimation of distance, the following table can be used:
Features of the vision on the route of various objects. Depend on many factors, and primarily on the distance to objects.
The farther the item is located, the lower it looks and narrower than in reality.
Therefore, large objects seem closer than small ones. Lying objects (such as a fallen tree) appear longer than standing objects of the same size:
When orienting and estimating the distance along the route, it must be remembered that the steepness of the exposed slopes seems usually greater than the forested ones; the distance to the distant forest, river, mountain is shorter than the real one; flat road - shorter than the same road on the road.
The kilometers covered under a heavy backpack, in bad weather or in conditions of poor visibility, are “lengthening”:
The distance on the water, in the gorge, on the snow seems shorter than the actual one. The width of the river from a gentle bank appears to be greater than when observed from a steep bank.
When viewed from top to top, from the foot of the mountain to its top, the slope seems less steep, and objects on the mountain are closer than when viewed from top to bottom, from the mountain. At night, all light sources and brightly lit objects appear much closer to their actual position.
In the afternoon, objects that are light or painted in bright colors appear closer than objects that are dark or have little contrast with the natural background:
Table of the distance of the beginning of the visibility of objects:
Distance determination using the AK-47/74 front sight:
Naturally, these data are rounded, but this is an order of magnitude more accurate than determining the distance to the eye: Average height - 1.75 m., Running -1.5 m., Shoulders -0.5 m, in winter clothes shoulders -0.6 m.
Item names and distance to them
- Settlements 10-12 km
- Large buildings 8 km
- Separate small houses 5 km
- Windows in houses (without binding) 4 km
- Roof pipes 3 km
- Separate trees 2 km
- People (in the form of dots) 1.5—2 km
- Movement of the legs, arms of a person 700 m
- Bindings of window frames 500 m
- Human head 400 m
- Color and parts of clothing 250-300 m
- Leaves on the trees 200 m
- Facial features, hands 100 m
- Eyes (in the form of dots) 60-70 m
- Belfries and large towers 15000-20000 m
- Windmills 10,000 m
- Villages and large houses 8000 m
- Windows in houses 4000 m
- Roof pipes 3000 m
- Separate trees 2000 m
- People like points 2000 m
- Distinguish a rider from a pedestrian 1000 m
- Tree trunks 900 m
- Distinguish pedestrian from equestrian 700 m
- Horse leg movement 600 m
- Window bindings 500 m
- Hand movement 400 m
- Colors and parts of clothing 250 m
- Human face 200 m
- Roof tiles and roof boards 200 m
- Buttons and metal clothing decorations 150 m
- Facial expression 100 m
- Eyes (appear to be separate points) 70 m
- Eyes and mouth (clearly distinguishable) 35 m
- Eye whites 20 m
- Burning bonfire 6-8 km
- Light of a flashlight 1,5-2 km
- Burning match 1-1.5 km
- Fire cigarettes 400-500 m
Of course, when eye-measuring distances, one must take into account the fact that people's vision is different. Therefore, when using the table, you need to check the data presented in practice and make the necessary correction for yourself.
In addition, you should always remember:
- Brightly lit objects seem closer. For example, a bonfire or fire always seems closer than the true distance.
- Items painted in bright colors - white, yellow and red - seem closer.
- In the fog, distances seem longer, and after rain, when there is no dust, closer. At dusk all objects seem farther.
- When the sun is ahead of the observer, then the estimated distances are less, and when, the sun from behind is more than true.
- Large objects seem closer than small ones.
- Items located on level ground seem closer than the same items located on hilly terrain or behind any screening. That is why the opposite side of a river or lake always seems closer than it really is.
- When viewed from bottom to top, objects appear closer than when viewed from top to bottom. For this reason, to a person at the bottom of a mountain, the mountain always seems cooler.
- The darker the background the subject is on, the farther it appears. Because of this, a house against the sky always seems closer than the same house against a dark background of a forest or mountain.
The accuracy of eye measurement of distance depends on the skill, as well as on the size of the measured distances. When determining distances over 1 km, the error can reach 50%. At small distances from experienced observers, the error does not exceed 10%.
Determining distance using angle measurement
This method is more difficult requires training. The starting position for measuring distances in this way is the following rule: each object visible at an angle of 1 ° is removed at a distance of 57 times its diameter. An object visible at an angle of 2 ° is removed by 28 diameters; at an angle of 5 ° - 11 diameters; at an angle of 7 ° - by 8 diameters, and so on. If you know the angle at which the object is visible, you can approximately determine the distance to it. The easiest way to measure is with the index finger. It is necessary to extend the hand and raise the index finger (the distance from the finger to the eyes is taken at 60 cm). The subject, which is covered with the fingernail of the index finger (nail width 1 cm), is usually visible at an angle of 1 ° and is at a distance of 57 times its diameter. If the nail covers only half of the object, then its angular value is 2 °, and the distance to it is equal to 28 of its diameters. For measurements, you can use the nail joint of the thumb. Its length is usually 3.5 cm. The subject, which is covered by this joint with an outstretched arm, is visible at an angle of about 3 ° and is removed 18 times more than its diameter.
Determining the height of objects
There are several simple ways to determine the height of objects. Hunters should be familiar with some of them.
By the shadow. On a sunny day, it is not difficult to measure the height of an object, suppose a tree by its shadow. It is only necessary to be guided by the following rule: the height of the measured tree is so many times greater than the height of an object you know (for example, a stick or a gun), how many times the shadow of a tree is greater than the shadow of a stick. If, in our measurement, the shadow from the gun or stick is two times the length of the gun or stick, then the height of the tree will be half the length of its shadow. In the same case, when the shadow from the gun or stick is equal to their length, the height of the tree is also equal to its shadow.
On a pole. This method can be used when there is no sun and no shadow from objects. To measure, you need to take a pole, equal in length to your height. This pole should be installed at a distance from the tree so that lying you can see the top of the tree in one straight line with the top point of the pole. Then the height of the tree will be equal to the line drawn from your head to the base of the tree.
In a puddle. This method can be successfully applied after rain, when many puddles appear on the ground. The measurement is carried out in this way: they find a puddle not far from the measured object and stand near it so that it fits between you and the object. After that, find the point from which the vertex of the object reflected in the water is visible. A measured object, such as a tree, will be so many times taller than you, how much distance from it to the puddle is greater than the distance from the puddle to you. Instead of a puddle, you can use the horizontally laid mirror.
Determination of the width of water bodies
The first way. It is necessary to approach as close as possible to the water and notice on the opposite shore two any objects located at the very edge of the water. Then you need to take a blade of grass (stick, twine) and, holding it horizontally at the ends with both outstretched arms, close one eye. Looking over a blade of grass, it is necessary to close the gap between the observed landmarks. After this, you should note the point where you are, fold the blade of grass in half and move away from the reservoir at right angles to another point from which the distance between the landmarks will be closed by a shortened blade of grass. The distance from this point to the river where you measured for the first time will be equal to the width of the reservoir.
The second way. You need to go up to the water, spot on the opposite shore any clearly visible object A, located at the very edge of the water, and mark your standing point with a stone or peg B. Then you need to walk along the shore along a line perpendicular to the direction between A and B, exactly 30 steps, stick stick B, count down another 30 steps and make a new note G. After that, turning your back to the shore, you need to go from note G to point D until the stick is in line with the object beyond the river A. will be equal to the width of the pond
The third way. You need to put a cap or a cap on your head, go up to the very shore and look at it so that the visor covers the shore. After that, without changing the tilt of the head, you need to turn half-turn and notice a place on the shore, which is covered by a visor. The number of steps to this point on your shore will indicate the width of the reservoir. ”
The table shows the range of the onset of audibility of sounds in an open area under conditions of silence and at normal humidity.
At night and in fog, when observation is limited or impossible at all (and on very rough terrain and in the forest, both at night and during the day), hearing comes to the aid of vision.
We must learn to determine the nature of sounds (that is, what they mean), the distance to the sources of sounds, and the direction from which they come.
If various sounds are heard, a person should be able to distinguish them from one another. The development of this ability is achieved by long training (in the same way, a professional musician distinguishes the voices of instruments in an orchestra).
Almost all sounds that indicate danger are made by humans.
Therefore, if a person hears even the slightest suspicious noise, he should freeze in place and listen.
It is possible that an enemy lurked near him.
If the enemy begins to move first, thereby giving out his location, then he will die first.
In the same way, an inexperienced or impatient hunter gives out his presence to the beast he is hunting for.
A skilled hunter is superior to animals in his endurance.
On a quiet summer night, even an ordinary human voice in an open space is heard far, sometimes for half a kilometer.
On a frosty autumn or winter night, all kinds of sounds and noises are heard very far.
This applies to speech, and steps, and tinkling utensils or weapons.
In foggy weather, sounds are also heard far, but their direction is difficult to determine.
On the surface of calm water and in the forest, when there is no wind, sounds are carried over a very long distance.
But the rain greatly drowns out the sounds.
The wind blowing towards a person brings sounds closer, and o removes from him.
He also sets the sound aside, creating a distorted idea of the location of its source.
Mountains, forests, buildings, ravines, ravines and deep hollows change the direction of sound, creating an echo.
Generate echoes and water spaces, contributing to its spread over long distances.
The sound changes when its source moves along soft, wet or hard soil, along the street, along a country or field road, along a pavement or leafy soil.
Keep in mind that dry earth conveys sounds better than air.
Therefore, they listen, putting their ears to the ground or to the trunks of trees.
At night, sounds are well transmitted through the earth.
There are certain ways to help listen at night, namely:
- lying: put your ear to the ground;
- standing: lean one end of the stick against the ear, rest the other end against the ground;
- leaning: standing, leaning slightly forward, shifting the center of gravity of the body to one leg, with a half-open mouth - the teeth are a conductor of sound.
A trained person during sneaking, if only he cherishes life, lies on his stomach and listens lying, trying to determine the direction of sounds.
This is easier to do by turning one ear in the direction where the suspicious noise is coming from.
In order to improve audibility, it is recommended that bent palms, a bowler hat, a pipe section be attached to the auricle.
To better listen to sounds, a person can put his ear to a dry board laid on the ground, which acts as a sound collector, or to a dry log dug into the ground.
If necessary, you can make a homemade water stethoscope.
To do this, use a glass bottle (or a metal flask) filled with water to the neck, which is buried in the ground to the water level in it. A tube (plastic) is tightly inserted into the cork, on which a rubber tube is put on. The other end of the rubber tube, equipped with a tip, is inserted into the ear.
To test the sensitivity of the device, hit the ground with your finger at a distance of 4 m from it (the sound from the impact is clearly heard through the rubber tube).
Sources of sound (Average range of the beginning of audibility):
- The noise of a running train 5-10 km
- Hunting rifle shooting 2—4 km
- The sharp noise of the tractor’s engine, tractor, car honking 2—3 km
- Barking of dogs, neighing of horses 1-2 km
- The movement of cars on the highway 1-2 km
- Loud scream (inaudible) 1–1.5 km
- The movement of cars on a dirt road 0.5-1 km
- Fall, crackling of a felled tree 800 m
- Knocking of an ax, screeching of a saw, tinkling of bowlers 300-500 m
- People Talk (Inaudible) 200 m
- Silent speech, coughing 50-100 m